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Gürbüz AK, Demirel A. The effect of single-limb exercises on functional exercise capacity, pulmonary function and dyspnea in patients with COPD. Heart Lung 2024; 68:98-106. [PMID: 38941773 DOI: 10.1016/j.hrtlng.2024.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Revised: 05/14/2024] [Accepted: 06/10/2024] [Indexed: 06/30/2024]
Abstract
BACKGROUND Aeorobic exercise is an essential component of the pulmonary rehabilitation program for patients with chronic obstructive pulmonary disease (COPD). Single-limb exercises are a type of aeorobic exercise that aims to increase patient tolerance by reducing the workload of the respiratory system. OBJEKTIVES The aim of our systematic review was to determine the effects of single-limb exercises on pulmonary function, dyspnea, fatigue, and muscle dysfunction in patients with COPD. METHODS Searches were performed using PubMed, Pedro, Google Scholar, MEDLINE, EMBASE, Scopus, Cochrane Library, Web of Science databases. Publications from the beginning to 2023 searched. Studies were selected by two authors by scanning the title, Mesh terms abstract in Rayyan QCRI software. Selected studies were subjected to full-text screening by applying selection criteria. Randomized controlled, case-control, cohort studies were included. RESULTS In the first screening according to mesh terms, 1011 articles were identified. After the screening criteria and duplicate articles were evaluated, 10 articles were included. This systematic review includes seven case-control, one randomized control trial (RCT), one cross-sectional, and one non-randomized study. A total of 157 patients with COPD received treatment in these studies. According to the Bakker scale, single-limb exercises have been shown to improve pulmonary function with strong evidence. There is strong evidence that single-limb exercises have no effect on dyspnea and fatigue in COPD patients. There is limited evidence that single-limb exercises have an effect on functional exercise capacity. CONCLUSION Single-limb exercise can advised in terms of improving pulmonary function in patients with COPD. Current systematic review has found single limb exercise has no effect on dyspnea and fatigue perception. No side effects were reported in the studies and these exercises can be considered safe.
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Affiliation(s)
- Alper Kemal Gürbüz
- Kırıkkale University, Health Science Faculty, Physical Therapy and Rehabilitation Departmant, Turkey.
| | - Aynur Demirel
- Hacettepe University, Faculty Physical Therapy and Rehabilitation, 06100, Samanpazari, Ankara, Turkey.
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2
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Asmussen MJ, Casto E. E, MacInnis MJ, Nigg BM. Counterweight mass influences single-leg cycling biomechanics. PLoS One 2024; 19:e0304136. [PMID: 38848389 PMCID: PMC11161077 DOI: 10.1371/journal.pone.0304136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 05/07/2024] [Indexed: 06/09/2024] Open
Abstract
INTRODUCTION Single-leg cycling is a commonly used intervention in exercise physiology that has applications in exercise training and rehabilitation. The addition of a counterweight to the contralateral pedal helps single-leg cycling mimic cycling patterns of double-leg cycling. To date, no research has tested (a) the influence of a wide range of counterweight masses on a person's cycling biomechanics and (b) the optimal counterweight mass to emulate double-leg cycling. OBJECTIVES The purpose of this study was to determine the effects of varying counterweights on the kinematics (joint angles) and kinetics (joint moments, work) of cycling using a 3D analysis. METHODS Twelve participants cycled at 50W or 100W with different counterweight masses (0 to 30 lbs, 2.5 lbs increments), while we analyzed the pedal force data, joint angles, joint moments, and joint power of the lower limb using 3D motion capture and 3D instrumented pedals to create participant-specific musculoskeletal models. RESULTS The results showed that no single-leg cycling condition truly emulated double-leg cycling with respect to all measured variables, namely pedal forces (p ≤ 0.05), joint angles (p ≤ 0.05), joint moments(p ≤ 0.05), and joint powers (p ≤ 0.05), but higher counterweights resulted in single-leg cycling that was statistically similar (p > 0.05), but descriptively, asymptotically approached the biomechanics of double-leg cycling. CONCLUSION We suggest that a 20-lb counterweight is a conservative estimate of the counterweight required for using single-leg cycling in exercise physiology studies, but further modifications are needed to the cycle ergometer for the biomechanics of single-leg cycling to match those of double-leg cycling.
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Affiliation(s)
- Michael J. Asmussen
- Department of Kinesiology, Faculty of Education, Vancouver Island University, Nanaimo, BC, Canada
- Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Erica Casto E.
- Department of Kinesiology, University of Massachusetts-Amherst, Amherst, MA, United States of America
| | - Martin J. MacInnis
- Department of Kinesiology, Faculty of Education, Vancouver Island University, Nanaimo, BC, Canada
| | - Benno M. Nigg
- Department of Kinesiology, Faculty of Education, Vancouver Island University, Nanaimo, BC, Canada
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3
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Haddad T, Spence AL, Peiffer JJ, Blain GM, Brisswalter J, Abbiss CR. Single- Versus Double-Leg Cycling: Small Muscle Mass Exercise Improves Exercise Capacity to a Greater Extent in Older Compared With Younger Population. J Aging Phys Act 2024; 32:408-415. [PMID: 38350440 DOI: 10.1123/japa.2023-0234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 10/12/2023] [Accepted: 11/27/2023] [Indexed: 02/15/2024]
Abstract
Manipulating the amount of muscle mass engaged during exercise can noninvasively inform the contribution of central cardiovascular and peripheral vascular-oxidative functions to endurance performance. To better understand the factors contributing to exercise limitation in older and younger individuals, exercise performance was assessed during single-leg and double-leg cycling. 16 older (67 ± 5 years) and 14 younger (35 ± 5 years) individuals performed a maximal exercise using single-leg and double-leg cycling. The ratio of single-leg to double-leg cycling power (RatioPower SL/DL) was compared between age groups. The association between fitness (peak oxygen consumption, peak power output, and physical activity levels) and RatioPower SL/DL was explored. The RatioPower SL/DL was greater in older compared with younger individuals (1.14 ± 0.11 vs. 1.06 ± 0.08, p = .041). The RatioPower SL/DL was correlated with peak oxygen consumption (r = .886, p < .001), peak power output relative to body mass (r = .854, p < .001), and levels of physical activity (r = .728, p = .003) in the younger but not older subgroup. Reducing the amount of muscle mass engaged during exercise improved exercise capacity to a greater extent in older versus younger population and may reflect a greater reduction in central cardiovascular function compared with peripheral vascular-oxidative function with aging.
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Affiliation(s)
- Toni Haddad
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
- Université Côte d'Azur, LAMHESS, Nice, France
| | - Angela L Spence
- Curtin School of Allied Health, Exercise and Sport Science Discipline, Curtin University, Perth, WA, Australia
- Curtin Health Innovation Research Institute, Curtin University, Perth, WA, Australia
| | | | | | | | - Chris R Abbiss
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, Joondalup, WA, Australia
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4
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Zhang J, Murias JM, MacInnis MJ, Aboodarda SJ, Iannetta D. Performance and perceived fatigability across the intensity spectrum: role of muscle mass during cycling. Am J Physiol Regul Integr Comp Physiol 2024; 326:R472-R483. [PMID: 38557152 DOI: 10.1152/ajpregu.00272.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Revised: 03/19/2024] [Accepted: 03/28/2024] [Indexed: 04/04/2024]
Abstract
The role of muscle mass in modulating performance and perceived fatigability across the entire intensity spectrum during cycling remains unexplored. We hypothesized that at task failure (Tlim), muscle contractile function would decline more following single- (SL) versus double-leg (DL) cycling within severe and extreme intensities, but not moderate and heavy intensities. After DL and SL ramp-incremental tests, on separate days, 11 recreationally active males (V̇o2max: 49.5 ± 7.7 mL·kg-1·min-1) completed SL and DL cycling until Tlim within each intensity domain. Power output for SL trials was set at 60% of the corresponding DL trial. Before and immediately after Tlim, participants performed an isometric maximal voluntary contraction (MVC) coupled with one superimposed and three resting femoral nerve stimulations [100 Hz; 10 Hz; single twitch (Qtw)] to measure performance fatigability. Perceived fatigue, leg pain, dyspnea, and effort were collected during trials. Tlim within each intensity domain was not different between SL and DL (all P > 0.05). MVC declined more for SL versus DL following heavy- (-42 ± 16% vs. -30 ± 18%; P = 0.011) and severe-intensity cycling (-41 ± 12% vs. -31 ± 15%; P = 0.036). Similarly, peak Qtw force declined more for SL following heavy- (-31 ± 12% vs. -22 ± 10%; P = 0.007) and severe-intensity cycling (-49 ± 13% vs. -40 ± 7%; P = 0.048). Except for heavy intensity, voluntary activation reductions were similar between modes. Similarly, except for dyspnea, which was lower for SL versus DL across all domains, ratings of fatigue, pain, and effort were similar at Tlim between exercise modes. Thus, the amount of muscle mass modulates the extent of contractile function impairment in an intensity-dependent manner.NEW & NOTEWORTHY We investigated the modulatory role of muscle mass on performance and perceived fatigability across the entire intensity spectrum. Despite similar time-to-task failure, single-leg cycling resulted in greater impairments in muscle contractile function within the heavy- and severe-intensity domains, but not the moderate- and extreme-intensity domains. Perceived fatigue, pain, and effort were similar between cycling modes. This indicates that the modulatory role of muscle mass on the extent of performance fatigability is intensity domain-dependent.
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Affiliation(s)
- Jenny Zhang
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Juan M Murias
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
- College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Martin J MacInnis
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Saied J Aboodarda
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Danilo Iannetta
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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5
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Brown A, Parise G, Thomas ACQ, Ng SY, McGlory C, Phillips SM, Kumbhare D, Joanisse S. Low baseline ribosome-related gene expression and resistance training-induced declines in ribosome-related gene expression are associated with skeletal muscle hypertrophy in young men and women. J Cell Physiol 2024; 239:e31182. [PMID: 38214457 DOI: 10.1002/jcp.31182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 12/04/2023] [Accepted: 12/12/2023] [Indexed: 01/13/2024]
Abstract
Ribosomes are essential cellular machinery for protein synthesis. It is hypothesised that ribosome content supports muscle growth and that individuals with more ribosomes have greater increases in muscle size following resistance training (RT). Aerobic conditioning (AC) also elicits distinct physiological adaptations; however, no measures of ribosome content following AC have been conducted. We used ribosome-related gene expression as a proxy measure for ribosome content and hypothesised that AC and RT would increase ribosome-related gene expression. Fourteen young men and women performed 6 weeks of single-legged AC followed by 10 weeks of double-legged RT. Muscle biopsies were taken following AC and following RT in the aerobically conditioned (AC+RT) and unconditioned (RT) legs. No differences in regulatory genes (Ubf, Cyclin D1, Tif-1a and Polr-1b) involved in ribosomal biogenesis or ribosomal RNA (45S, 5.8S, 18S and 28S rRNAs) expression were observed following AC and RT, except for c-Myc (RT > AC+RT) and 5S rRNA (RT < AC+RT at pre-RT) with 18S external transcribed spacer and 5.8S internal transcribed spacer expression decreasing from pre-RT to post-RT in the RT leg only. When divided for change in leg-lean soft tissue mass (ΔLLSTM) following RT, legs with the greatest ΔLLSTM had lower expression in 11/13 measured ribosome-related genes before RT and decreased expression in 9/13 genes following RT. These results indicate that AC and RT did not increase ribosome-related gene expression. Contrary to previous research, the greatest increase in muscle mass was associated with lower changes in ribosome-related gene expression over the course of the 10-week training programme. This may point to the importance of translational efficiency rather than translational capacity (i.e. ribosome content) in mediating long-term exercise-induced adaptations in skeletal muscle.
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Affiliation(s)
- Alex Brown
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Gianni Parise
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Aaron C Q Thomas
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Sean Y Ng
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Chris McGlory
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Stuart M Phillips
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Dinesh Kumbhare
- Toronto Rehabilitation Institute, University of Toronto, Toronto, Ontario, Canada
| | - Sophie Joanisse
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
- Institute of Sport, Manchester Metropolitan University, Manchester, UK
- MRC Versus Arthritis Centre for Musculoskeletal Ageing Research, Nottingha, UK
- School of Life Sciences, University of Nottingham, Nottingham, UK
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6
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Haddad T, Spence AL, Peiffer J, Blain GM, Brisswalter J, Abbiss CR. The Improvement in Exercise Performance during Reduced Muscle Mass Exercise is Associated with an Increase in Femoral Blood Flow in Older and Younger Endurance-Trained Athletes. J Sports Sci Med 2024; 23:46-55. [PMID: 38455445 PMCID: PMC10915611 DOI: 10.52082/jssm.2024.46] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 12/01/2023] [Indexed: 03/09/2024]
Abstract
This study investigated whether the improved performance observed with maximal self-paced single-leg (SL), compared with double-leg (DL) cycling, is associated with enhanced femoral blood flow and/or altered tissue oxygenation. The hyperaemic response to exercise was assessed in younger and older athletes. Power output was measured in 12 older (65 ± 4 y) and 12 younger (35 ± 5 y) endurance-trained individuals performing 2 x 3 min maximal self-paced exercise using SL and DL cycling. Blood flow (BF) in the femoral artery was assessed using Doppler ultrasound and muscle oxygenation was measured using near-infrared spectroscopy on the vastus lateralis. SL cycling elicited a greater power output (295 ± 83 vs 265 ± 70 W, P < 0.001) and peak femoral BF (1749.1 ± 533.3 vs 1329.7 ± 391.7 ml/min, P < 0.001) compared with DL cycling. Older individuals had a lower peak BF in response to exercise (1355.4 ± 385.8 vs 1765.2 ± 559.6 ml/min, P = 0.019) compared with younger individuals. Peak BF in response to exercise was correlated with power output during SL (r = 0.655, P = 0.002) and DL (r = 0.666, P = 0.001) cycling. The greater exercise performance during SL compared with DL cycling may be partly explained by a greater hyperaemic response when reducing active muscle mass. Despite regular endurance training, older athletes had a lower femoral BF in response to maximal self-paced exercise compared with younger athletes.
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Affiliation(s)
- Toni Haddad
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
- Université Côte d'Azur, LAMHESS, France
| | - Angela L Spence
- Curtin School of Allied Health, Exercise and Sport Science Discipline, Curtin University, WA, Australia
- Curtin Health Innovation Research Institute, Curtin University, WA, Australia
| | - Jeremiah Peiffer
- Centre for Healthy Ageing, Murdoch University, Murdoch, WA, Australia
| | | | | | - Chris R Abbiss
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
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7
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Cayot TE, Herbert B, Klika RJ. Treatment side affects exercising microvascular oxygenation response in active breast cancer survivors: A pilot study. Clin Physiol Funct Imaging 2023; 43:96-102. [PMID: 36376074 DOI: 10.1111/cpf.12796] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/19/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022]
Abstract
Cancer treatment is associated with cardiovascular toxicity, skeletal muscle dysfunction and interruptions in mitochondrial respiration. Microvascular oxygenation responses, measured via near-infrared spectroscopy (NIRS), at peak exercise intensity has previously been associated with aerobic capacity. Specifically, the greater magnitude of microvascular deoxygenation observed at peak exercise intensity has been associated with higher aerobic capacity. Therefore, a pilot study investigated if diagnosis side (uninvolved side, treatment side) and/or exercise side (paddle side, non-paddle side) affected microvascular oxygenation responses at peak intensity during paddle exercise. Thirty-three breast cancer survivors (age = 57 ± 9 years, height = 1.64 ± 0.05 m, weight = 76.5 ± 15.6 kg, 7 ± 7 years since treatment) who also competed as dragon boat racers performed a unilateral (paddle), discontinuous graded exercise test (2-min exercise, 1-min rest) on a rowing ergometer to volitional fatigue. Tissue oxygenation saturation (StO2DIFF ) and total haemoglobin concentration (total[heme]DIFF ) responses at peak exercise intensity were measured bilaterally from the posterior deltoids using NIRS. Two-way analysis of variance determined if diagnosis side and/or exercise side effected StO2DIFF or total[heme]DIFF . Diagnosis side elicited a moderate effect (effect size = 0.66) on StO2DIFF , as the treatment side deoxygenated less (-6.0 ± 14.7 ∆BSL) compared to the uninvolved side (-16.9 ± 16.9 ∆BSL) at peak exercise intensity. No other significant main effects or interactions were observed for StO2DIFF or total[heme]DIFF . The pilot findings suggest that the ability of the exercising muscle to use oxygen for the purpose of mitochondrial oxidative respiration may be impaired on the treatment side.
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Affiliation(s)
- Trent E Cayot
- Department of Kinesiology, Health, and Sport Sciences, University of Indianapolis, Indianapolis, Indiana, USA
| | - Brooklyn Herbert
- Department of Kinesiology, Health, and Sport Sciences, University of Indianapolis, Indianapolis, Indiana, USA
| | - Riggs J Klika
- Department of Kinesiology, Health, and Sport Sciences, University of Indianapolis, Indianapolis, Indiana, USA.,Aspen Cancer Survivor Center, Aspen, Colorado, USA
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8
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Skelly LE, MacInnis MJ, Bostad W, McCarthy DG, Jenkins EM, Archila LR, Tarnopolsky MA, Gibala MJ. Human skeletal muscle mitochondrial responses to single-leg intermittent or continuous cycle exercise training matched for absolute intensity and total work. Scand J Med Sci Sports 2023; 33:872-881. [PMID: 36779702 DOI: 10.1111/sms.14332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 01/28/2023] [Accepted: 02/02/2023] [Indexed: 02/14/2023]
Abstract
There is renewed interest in the potential for interval (INT) training to increase skeletal muscle mitochondrial content including whether the response differs from continuous (CONT) training. Comparisons of INT and CONT exercise are impacted by the manner in which protocols are "matched", particularly with respect to exercise intensity, as well as inter-individual differences in training responses. We employed single-leg cycling to facilitate a within-participant design and test the hypothesis that short-term INT training would elicit a greater increase in mitochondrial content than work- and intensity-matched CONT training. Ten young healthy adults (five males and five females) completed 12 training sessions over 4 weeks with each leg. Legs were randomly assigned to complete either 30 min of CONT exercise at a challenging sustainable workload (~50% single-leg peak power output; Wpeak) or INT exercise that involved 10 × 3-min bouts at the same absolute workload. INT bouts were interspersed with 1 min of recovery at 10% Wpeak and each CONT session ended with 10 min at 10% Wpeak. Absolute and mean intensity, total training time, and volume were thus matched between legs but the pattern of exercise differed. Contrary to our hypothesis, biomarkers of mitochondrial content including citrate synthase maximal activity, mitochondrial protein content and subsarcolemmal mitochondrial volume increased after CONT (p < 0.05) but not INT training. Both training modes increased single-leg Wpeak (p < 0.01) and time to exhaustion at 70% of single-leg Wpeak (p < 0.01). In a work- and intensity-matched comparison, short-term CONT training increased skeletal muscle mitochondrial content whereas INT training did not.
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Affiliation(s)
- Lauren E Skelly
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Martin J MacInnis
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - William Bostad
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Devin G McCarthy
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | | | - Linda R Archila
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Mark A Tarnopolsky
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada.,Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
| | - Martin J Gibala
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
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9
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Heidorn CE, Elmer SJ, Wehmanen KW, Martin JC, McDaniel J. Single-leg cycling to maintain and improve function in healthy and clinical populations. Front Physiol 2023; 14:1105772. [PMID: 37187959 PMCID: PMC10175616 DOI: 10.3389/fphys.2023.1105772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 04/11/2023] [Indexed: 05/17/2023] Open
Abstract
Exercise with reduced muscle mass facilitates greater muscle-specific adaptations than training with larger muscle mass. The smaller active muscle mass can demand a greater portion of cardiac output which allows muscle(s) to perform greater work and subsequently elicit robust physiological adaptations that improve health and fitness. One reduced active muscle mass exercise that can promote greater positive physiological adaptations is single-leg cycling (SLC). Specifically, SLC confines the cycling exercise to a smaller muscle mass resulting in greater limb specific blood flow (i.e., blood flow is no longer "shared" by both legs) which allows the individual to exercise at a greater limb specific intensity or for a longer duration. Numerous reports describing the use of SLC have established cardiovascular and/or metabolic benefits of this exercise modality for healthy adults, athletes, and individuals living with chronic diseases. SLC has served as a valuable research tool for understanding central and peripheral factors to phenomena such as oxygen uptake and exercise tolerance (i.e., V̇O2peak and V̇O2 slow component). Together, these examples highlight the breadth of applications of SLC to promote, maintain, and study health. Accordingly, the purpose of this review was to describe: 1) acute physiological responses to SLC, 2) long-term adaptations to SLC in populations ranging from endurance athletes to middle aged adults, to individuals living with chronic disease (COPD, heart failure, organ transplant), and 3) various methods utilized to safely perform SLC. A discussion is also included on clinical application and exercise prescription of SLC for the maintenance and/or improvement of health.
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Affiliation(s)
- C. Eric Heidorn
- Vascular Health Lab, Exercise Physiology, Kent State University, Kent, OH, United States
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States
- *Correspondence: C. Eric Heidorn,
| | - Steven J. Elmer
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States
- Health Research Institute, Michigan Technological University, Houghton, MI, United States
| | - Kyle W. Wehmanen
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States
- Health Research Institute, Michigan Technological University, Houghton, MI, United States
| | - James C. Martin
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, United States
| | - John McDaniel
- Vascular Health Lab, Exercise Physiology, Kent State University, Kent, OH, United States
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States
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10
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Thomas ACQ, Brown A, Hatt AA, Manta K, Costa-Parke A, Kamal M, Joanisse S, McGlory C, Phillips SM, Kumbhare D, Parise G. Short-term aerobic conditioning prior to resistance training augments muscle hypertrophy and satellite cell content in healthy young men and women. FASEB J 2022; 36:e22500. [PMID: 35971745 DOI: 10.1096/fj.202200398rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 07/22/2022] [Accepted: 08/02/2022] [Indexed: 11/11/2022]
Abstract
Factors influencing inter-individual variability of responses to resistance training (RT) remain to be fully elucidated. We have proposed the importance of capillarization in skeletal muscle for the satellite cell (SC) response to RT-induced muscle hypertrophy, and hypothesized that aerobic conditioning (AC) would augment RT-induced adaptations. Fourteen healthy young (22 ± 2 years) men and women underwent AC via 6 weeks of unilateral cycling followed by 10 weeks of bilateral RT to investigate how AC alters SC content, activity, and muscle hypertrophy following RT. Muscle biopsies were taken at baseline (unilateral), post AC (bilateral), and post RT (bilateral) in the aerobically conditioned (AC + RT) and unconditioned (RT) legs. Immunofluorescence was used to determine muscle capillarization, fiber size, SC content, and activity. Type I and type II fiber cross-sectional area (CSA) increased following RT, and when legs were analyzed independently, AC + RT increased type I, type II, and mixed-fiber CSA, where the RT leg tended to increase type II (p = .05), but not type I or mixed-fiber CSA. SC content, activation, and differentiation increased with RT, where type I total and quiescent SC content was greater in AC + RT compared to the RT leg. Those with the greatest capillary-to-fiber perimeter exchange index before RT had the greatest change in CSA following RT and a significant relationship was observed between type II fiber capillarization and the change in type II-fiber CSA with RT (r = 0.35). This study demonstrates that AC prior to RT can augment RT-induced muscle adaptions and that these differences are associated with increases in capillarization.
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Affiliation(s)
- Aaron C Q Thomas
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Alex Brown
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Aidan A Hatt
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Katherine Manta
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Anamaria Costa-Parke
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Michael Kamal
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Sophie Joanisse
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada.,Musculoskeletal Sciences and Sport Medicine Research Centre, Department of Sport and Exercise Sciences, Faculty of Science and Engineering, Manchester Metropolitan University, Manchester, UK.,Manchester Metropolitan University Institute of Sport, Manchester, UK
| | - Chris McGlory
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada.,Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Stuart M Phillips
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | | | - Gianni Parise
- Exercise Metabolism Research Group, Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
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11
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The Effect of Endurance Training on Pulmonary V˙O 2 Kinetics in Solid Organs Transplanted Recipients. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19159097. [PMID: 35897466 PMCID: PMC9331393 DOI: 10.3390/ijerph19159097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/16/2022] [Accepted: 07/22/2022] [Indexed: 11/29/2022]
Abstract
Background: We investigated the effects of single (SL-ET) and double leg (DL-ET) high-intensity interval training on O2 deficit (O2Def) and mean response time (MRT) during square-wave moderate-intensity exercise (DL-MOD), and on the amplitude of V˙O2p slow component (SCamp), during heavy intensity exercise (DL-HVY), on 33 patients (heart transplant = 13, kidney transplanted = 11 and liver transplanted = 9). Methods: Patients performed DL incremental step exercise to exhaustion, two DL-MOD tests, and a DL-HVY trial before and after 24 sessions of SL-ET (n = 17) or DL-ET (n = 16). Results: After SL-ET, O2Def, MRT and SCamp decreased by 16.4% ± 13.7 (p = 0.008), by 15.6% ± 13.7 (p = 0.004) and by 35% ± 31 (p = 0.002), respectively. After DL-ET, they dropped by 24.9% ± 16.2 (p < 0.0001), by 25.9% ± 13.6 (p < 0.0001) and by 38% ± 52 (p = 0.0003), respectively. The magnitude of improvement of O2Def, MRT, and SCamp was not significantly different between SL-ET and DL-ET after training. Conclusions: We conclude that SL-ET is as effective as DL-ET if we aim to improve V˙O2p kinetics in transplanted patients and suggest that the slower, V˙O2p kinetics is mainly caused by the impairment of peripherals exchanges likely due to the immunosuppressive medications and disuse.
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12
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Draper S, Singer T, Dulaney C, McDaniel J. Single Leg Cycling Offsets Reduced Muscle Oxygenation in Hypoxic Environments. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19159139. [PMID: 35897502 PMCID: PMC9331301 DOI: 10.3390/ijerph19159139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/19/2022] [Accepted: 07/21/2022] [Indexed: 12/04/2022]
Abstract
The intensity of large muscle mass exercise declines at altitude due to reduced oxygen delivery to active muscles. The purpose of this investigation was to determine if the greater limb blood flow during single-leg cycling prevents the reduction in tissue oxygenation observed during traditional double-leg cycling in hypoxic conditions. Ten healthy individuals performed bouts of double and single-leg cycling (4, four-minute stages at 50−80% of their peak oxygen consumption) in hypoxic (15% inspired O2) and normoxic conditions. Heart rate, mean arterial pressure, femoral blood flow, lactate, oxygenated hemoglobin, total hemoglobin, and tissue saturation index in the vastus lateralis were recorded during cycling tests. Femoral blood flow (2846 ± 912 mL/min) and oxygenated hemoglobin (−2.98 ± 3.56 au) during single-leg cycling in hypoxia were greater than double-leg cycling in hypoxia (2429 ± 835 mL/min and −6.78 ± 3.22 au respectively, p ≤ 0.01). In addition, tissue saturation index was also reduced in the double-leg hypoxic condition (60.2 ± 3.1%) compared to double-leg normoxic (66.0 ± 2.4%, p = 0.008) and single-leg hypoxic (63.3 ± 3.2, p < 0.001) conditions. These data indicate that while at altitude, use of reduced muscle mass exercise can help offset the reduction in tissue oxygenation observed during larger muscle mass activities allowing athletes to exercise at greater limb/muscle specific intensities.
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Affiliation(s)
- Shane Draper
- Department of Exercise Science and Outdoor Recreation, Utah Valley University, Orem, UT 84058, USA;
| | - Tyler Singer
- Department of Exercise Science, Fairmont State University, Fairmont, WV 26554, USA;
| | - Cody Dulaney
- Department of Fitness and Wellness Leadership, State University of New York Plattsburgh, Plattsburgh, NY 12901, USA;
| | - John McDaniel
- Department of Exercise Science, Kent State University, Kent, OH 44242, USA
- Advanced Platform Technology Center, VA Northeast Ohio Healthcare System, Cleveland, OH 44106, USA
- Correspondence:
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13
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Del Torto A, Capelli C, Peressutti R, di Silvestre A, Livi U, Nalli C, Sponga S, Amici G, Baccarani U, Lazzer S. Effect of small vs large muscle mass endurance training on maximal oxygen uptake in organ transplanted recipients. Appl Physiol Nutr Metab 2021; 46:994-1003. [PMID: 34315281 DOI: 10.1139/apnm-2020-0987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Maximal oxygen consumption (V̇O2max) is impaired in heart (HTx), kidney (KTx), and liver (LTx) transplanted recipients and the contribution of the cardiovascular, central, and peripheral (muscular) factors in affecting V̇O2max improvement after endurance training (ET) has never been quantified in these patients. ET protocols involving single leg cycling (SL) elicit larger improvements of the peripheral factors affecting O2 diffusion and utilization than the double leg (DL) cycling ET. Therefore, this study aimed to compare the effects of SL-ET vs DL-ET on V̇O2max. We determined the DL-V̇O2max and maximal cardiac output before and after 24 SL-ET vs DL-ET sessions on 33 patients (HTx = 13, KTx = 11 and LTx = 9). The DL-V̇O2max increased by 13.8% ± 8.7 (p < 0.001) following the SL-ET, due to a larger maximal O2 systemic extraction; meanwhile, V̇O2max in DL-ET increased by 18.6% ± 12.7 (p < 0.001) because of concomitant central and peripheral adaptations. We speculate that in transplanted recipients, SL-ET is as effective as DL-ET to improve V̇O2max and that the impaired peripheral O2 extraction and/or utilization play an important role in limiting V̇O2max in these types of patients. Novelty: SL-ET increases V̇O2max in transplanted recipients because of improved peripheral O2 extraction and/or utilization. SL-ET is as successful as DL-ET to improve the cardiorespiratory fitness in transplanted recipients. The model of V̇O2max limitation indicates the peripheral factors as a remarkable limitation to the V̇O2max in these patients.
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Affiliation(s)
- Alessio Del Torto
- Department of Medicine, University of Udine, Udine, Italy.,School of Sport Sciences, University of Udine, Udine, Italy
| | - Carlo Capelli
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Italy
| | - Roberto Peressutti
- Regional Transplantation Centre, Friuli Venezia Giulia Region, Udine, Italy
| | | | - Ugolino Livi
- Department of Medicine, University of Udine, Udine, Italy.,Cardiac Surgery Unit, University Hospital of Udine, Udine, Italy
| | - Chiara Nalli
- Department of Medicine, University of Udine, Udine, Italy.,Cardiac Surgery Unit, University Hospital of Udine, Udine, Italy
| | - Sandro Sponga
- Department of Medicine, University of Udine, Udine, Italy.,Cardiac Surgery Unit, University Hospital of Udine, Udine, Italy
| | - Gianpaolo Amici
- Nephrology and Dialysis Unit, San Daniele del Friuli Hospital, Udine, Italy
| | - Umberto Baccarani
- Department of Medicine, University of Udine, Udine, Italy.,Liver-Kidney Transplant Unit, University Hospital of Udine, Udine, Italy
| | - Stefano Lazzer
- Department of Medicine, University of Udine, Udine, Italy.,School of Sport Sciences, University of Udine, Udine, Italy
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Maximal muscular power: lessons from sprint cycling. SPORTS MEDICINE-OPEN 2021; 7:48. [PMID: 34268627 PMCID: PMC8282832 DOI: 10.1186/s40798-021-00341-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 06/29/2021] [Indexed: 02/07/2023]
Abstract
Maximal muscular power production is of fundamental importance to human functional capacity and feats of performance. Here, we present a synthesis of literature pertaining to physiological systems that limit maximal muscular power during cyclic actions characteristic of locomotor behaviours, and how they adapt to training. Maximal, cyclic muscular power is known to be the main determinant of sprint cycling performance, and therefore we present this synthesis in the context of sprint cycling. Cyclical power is interactively constrained by force-velocity properties (i.e. maximum force and maximum shortening velocity), activation-relaxation kinetics and muscle coordination across the continuum of cycle frequencies, with the relative influence of each factor being frequency dependent. Muscle cross-sectional area and fibre composition appear to be the most prominent properties influencing maximal muscular power and the power-frequency relationship. Due to the role of muscle fibre composition in determining maximum shortening velocity and activation-relaxation kinetics, it remains unclear how improvable these properties are with training. Increases in maximal muscular power may therefore arise primarily from improvements in maximum force production and neuromuscular coordination via appropriate training. Because maximal efforts may need to be sustained for ~15-60 s within sprint cycling competition, the ability to attenuate fatigue-related power loss is also critical to performance. Within this context, the fatigued state is characterised by impairments in force-velocity properties and activation-relaxation kinetics. A suppression and leftward shift of the power-frequency relationship is subsequently observed. It is not clear if rates of power loss can be improved with training, even in the presence adaptations associated with fatigue-resistance. Increasing maximum power may be most efficacious for improving sustained power during brief maximal efforts, although the inclusion of sprint interval training likely remains beneficial. Therefore, evidence from sprint cycling indicates that brief maximal muscular power production under cyclical conditions can be readily improved via appropriate training, with direct implications for sprint cycling as well as other athletic and health-related pursuits.
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15
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Zhang J, Iannetta D, Alzeeby M, MacInnis MJ, Aboodarda SJ. Exercising muscle mass influences neuromuscular, cardiorespiratory, and perceptual responses during and following ramp-incremental cycling to task failure. Am J Physiol Regul Integr Comp Physiol 2021; 321:R238-R249. [PMID: 34189949 DOI: 10.1152/ajpregu.00286.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Neuromuscular (NM), cardiorespiratory, and perceptual responses to maximal-graded exercise using different amounts of active muscle mass remain unclear. We hypothesized that during dynamic exercise, peripheral NM fatigue (declined twitch force) and muscle pain would be greater using smaller muscle mass, whereas central fatigue (declined voluntary activation) and ventilatory variables would be greater using larger muscle mass. Twelve males (29.8 ± 4.7 years) performed two ramp-incremental cycling tests until task failure: 1) single-leg (SL) with 10 W·min-1 ramp and 2) double-leg (DL) with 20 W·min-1 ramp. NM fatigue was assessed at baseline, task failure (post), and after 1, 4, and 8 min of recovery. Cardiorespiratory and perceptual variables [i.e., ratings of perceived exertion (RPE), pain, and dyspnea] were measured throughout cycling. Exercise duration was similar between sessions (SL: 857.7 ± 263.6 s; DL: 855.0 ± 218.8 s; P = 0.923), and higher absolute peak power output was attained in DL (SL: 163.2 ± 43.8 W; DL: 307.0 ± 72.0 W; P < 0.001). Although central fatigue did not differ between conditions (SL: -6.6 ± 6.5%; DL: -3.5 ± 4.8%; P = 0.091), maximal voluntary contraction (SL: -41.6 ± 10.9%; DL: -33.7 ± 8.5%; P = 0.032) and single twitch forces (SL: -59.4 ± 18.8%; DL: -46.2 ± 16.2%; P = 0.003) declined more following SL. DL elicited higher peak oxygen uptake (SL: 42.1 ± 10.0 mL·kg-1·min-1; DL: 50.3 ± 9.3 mL·kg-1·min-1; P < 0.001), ventilation (SL: 137.1 ± 38.1 L·min-1; DL: 171.5 ± 33.2 L·min-1; P < 0.001), and heart rate (SL: 167 ± 21 bpm; DL: 187 ± 8 bpm; P = 0.005). Dyspnea (P = 0.025) was higher in DL; however, RPE (P = 0.005) and pain (P < 0.001) were higher in SL. These results suggest that interplay between NM, cardiorespiratory, and perceptual determinants of exercise performance during ramp-incremental cycling to task failure is muscle mass dependent.
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Affiliation(s)
- Jenny Zhang
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Danilo Iannetta
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Mohammed Alzeeby
- Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Martin J MacInnis
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Saied J Aboodarda
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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16
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Gatterer H, Menz V, Burtscher M. Acute Moderate Hypoxia Reduces One-Legged Cycling Performance Despite Compensatory Increase in Peak Cardiac Output: A Pilot Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18073732. [PMID: 33918381 PMCID: PMC8038296 DOI: 10.3390/ijerph18073732] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/25/2021] [Accepted: 03/30/2021] [Indexed: 01/23/2023]
Abstract
In severe hypoxia, single-leg peak oxygen uptake (VO2peak) is reduced mainly due to the inability to increase cardiac output (CO). Whether moderate altitude allows CO to increase during single-leg cycling, thereby restoring VO2peak, has not been extensively investigated. Five healthy subjects performed an incremental, maximal, two-legged cycle ergometer test, and on separate days a maximal incremental one-leg cycling test in normoxia and in moderate hypoxia (fraction of inspired oxygen (FiO2) = 15%). Oxygen uptake, heart rate, blood pressure responses, power output, and CO (PhysioFlow) were measured during all tests. Moderate hypoxia lowered single-leg peak power output (154 ± 31 vs. 128 ± 26 watts, p = 0.03) and oxygen uptake (VO2) (36.8 ± 6.6 vs. 33.9 ± 6.9 mL/min/kg, p = 0.04), despite higher peak CO (16.83 ± 3.10 vs. 18.96 ± 3.59 L/min, p = 0.04) and systemic oxygen (O2) delivery (3.37 ± 0.84 vs. 3.47 ± 0.89 L/min, p = 0.04) in hypoxia compared to normoxia. Arterial–venous O2 difference (a–vDO2) was lower in hypoxia (137 ± 21 vs. 112 ± 19 mL/l, p = 0.03). The increases in peak CO from normoxia to hypoxia were negatively correlated with changes in mean arterial pressure (MABP) (p < 0.05). These preliminary data indicate that the rise in CO was not sufficient to prevent single-leg performance loss at moderate altitude and that enhanced baroreceptor activity might limit CO increases in acute hypoxia, likely by reducing sympathetic activation. Since the systemic O2 delivery was enhanced and the calculated a–vDO2 reduced in moderate hypoxia, a potential diffusion limitation cannot be excluded.
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Affiliation(s)
- Hannes Gatterer
- Institute of Mountain Emergency Medicine, Eurac Research, 39100 Bolzano, Italy
- Correspondence:
| | - Verena Menz
- Department of Sport Science, University of Innsbruck, 6020 Innsbruck, Austria; (V.M.); (M.B.)
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, 6020 Innsbruck, Austria; (V.M.); (M.B.)
- Austrian Society for High Altitude and Mountain Medicine, 6020 Innsbruck, Austria
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17
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Kilroe SP, Fulford J, Jackman S, Holwerda A, Gijsen A, van Loon L, Wall BT. Dietary protein intake does not modulate daily myofibrillar protein synthesis rates or loss of muscle mass and function during short-term immobilization in young men: a randomized controlled trial. Am J Clin Nutr 2021; 113:548-561. [PMID: 32469388 DOI: 10.1093/ajcn/nqaa136] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 05/12/2020] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Short-term (<1 wk) muscle disuse lowers daily myofibrillar protein synthesis (MyoPS) rates resulting in muscle mass loss. The understanding of how daily dietary protein intake influences such muscle deconditioning requires further investigation. OBJECTIVES To assess the influence of graded dietary protein intakes on daily MyoPS rates and the loss of muscle mass during 3 d of disuse. METHODS Thirty-three healthy young men (aged 22 ± 1 y; BMI = 23 ± 1 kg/m2) initially consumed the same standardized diet for 5 d, providing 1.6 g protein/kg body mass/d. Thereafter, participants underwent a 3-d period of unilateral leg immobilization during which they were randomly assigned to 1 of 3 eucaloric diets containing relatively high, low, or no protein (HIGH: 1.6, LOW: 0.5, NO: 0.15 g protein/kg/d; n = 11 per group). One day prior to immobilization participants ingested 400 mL deuterated water (D2O) with 50-mL doses consumed daily thereafter. Prior to and immediately after immobilization upper leg bilateral MRI scans and vastus lateralis muscle biopsies were performed to measure quadriceps muscle volume and daily MyoPS rates, respectively. RESULTS Quadriceps muscle volume of the control legs remained unchanged throughout the experiment (P > 0.05). Immobilization led to 2.3 ± 0.4%, 2.7 ± 0.2%, and 2.0 ± 0.4% decreases in quadriceps muscle volume (P < 0.05) of the immobilized leg in the HIGH, LOW, and NO groups (P < 0.05), respectively, with no significant differences between groups (P > 0.05). D2O ingestion resulted in comparable plasma free [2H]-alanine enrichments during immobilization (∼2.5 mole percentage excess) across groups (P > 0.05). Daily MyoPS rates during immobilization were 30 ± 2% (HIGH), 26 ± 3% (LOW), and 27 ± 2% (NO) lower in the immobilized compared with the control leg, with no significant differences between groups (P > 0.05). CONCLUSIONS Three days of muscle disuse induces considerable declines in muscle mass and daily MyoPS rates. However, daily protein intake does not modulate any of these muscle deconditioning responses.Clinical trial registry number: NCT03797781.
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Affiliation(s)
- Sean Paul Kilroe
- Department of Sport and Health Sciences, College of Life and Environmental Science, University of Exeter, Exeter, UK
| | - Jonathan Fulford
- University of Exeter Medical School, University of Exeter, Exeter, UK
| | - Sarah Jackman
- Department of Sport and Health Sciences, College of Life and Environmental Science, University of Exeter, Exeter, UK
| | - Andrew Holwerda
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Annemie Gijsen
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Luc van Loon
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Benjamin Toby Wall
- Department of Sport and Health Sciences, College of Life and Environmental Science, University of Exeter, Exeter, UK
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18
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Elmer SJ, Martin JC. Metabolic power and efficiency for an amputee cyclist: implications for cycling technique. J Appl Physiol (1985) 2021; 130:479-484. [PMID: 33356981 DOI: 10.1152/japplphysiol.00661.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cycling technique is steeped in cultural lore. One deeply held belief is that "pulling up" to lift the leg (increased muscular leg flexion) will optimize technique and improve efficiency. In contrast, scientific evidence suggests that when cyclists are instructed to pull-up efficiency decreases. However, such interventions may not have allowed sufficient time for cyclists to adapt and refine their technique. This case study documented how a cyclist with a complete unilateral limb amputation consumed metabolic power to produce mechanical power during single-leg cycling. The cyclist was a four time US National Paralympic Champion who performed single-leg cycling for 7 yr and thus was fully adapted to pull up. We hypothesized that a counterweight system, which reduced the requirement to pull up, would decrease metabolic power and increase efficiency for this cyclist. The cyclist performed submaximal cycling (100, 135, 170, 205 W, 80 rpm, 5 min) with and without a counterweight (10 kg) on the unused crank. Expired gases were measured, and metabolic power and gross efficiency were calculated. Metabolic power decreased on average by 87 ± 7 W (P < 0.001) and gross efficiency increased from 16.3 ± 1.9 to 18.0 ± 1.8% (P < 0.001) when cycling with the counterweight. During counterweighted single-leg cycling, the metabolic power of unloaded cycling decreased (317 vs. 238 W) and delta efficiency was similar (25.2 vs. 25.5%). Results demonstrated that significant metabolic power was associated with pulling up to produce muscular leg flexion power even in a cyclist who pulled up substantially during cycling. Our findings confirm observations from previous studies that altered pedaling technique acutely and indicate that pulling up during cycling is less efficient.NEW & NOTEWORTHY This study offers unique insight into pedaling technique and provides the "final nail in the coffin" to the notion that pulling up improves cycling efficiency. When the requirement for pulling up was reduced with the counterweight, the cyclist immediately benefited as the cost to move the limb decreased and gross efficiency increased. These case study results along with previous research suggest that, in general, cyclists should not adopt pedaling techniques, which increase the action of pulling up.
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Affiliation(s)
- Steven J Elmer
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, Michigan
| | - James C Martin
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
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Single leg aerobic capacity and strength in individuals with surgically repaired anterior cruciate ligaments. Phys Ther Sport 2020; 46:131-136. [PMID: 32932122 PMCID: PMC8108269 DOI: 10.1016/j.ptsp.2020.08.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 08/20/2020] [Accepted: 08/21/2020] [Indexed: 11/22/2022]
Abstract
OBJECTIVES Compare single-leg aerobic capacity and strength differences between the surgically repaired ACL leg (injured) and the uninjured leg. DESIGN Cross-sectional study. SETTING Laboratory. PARTICIPANTS Eight participants (5 female, 3 male, age = 23 ± 3.5 y, mass = 72.3 ± 17.3 kg, height = 169.7 ± 9.4 cm) that returned to play from ACL surgery between six and 18 months. MAIN OUTCOME MEASURES Participants performed an aerobically-based, single-leg cycling protocol to determine maximum oxygen consumption, ventilatory threshold, heart rate, rating of perceived exertion, and maximal watts cycled. Participants also performed isokinetic knee flexion and extension on a dynamometer to assess peak torque, total work, work fatigue, and power. RESULTS There were no statistical differences in single-leg aerobic capacity or strength outcomes between the injured and uninjured legs. CONCLUSIONS Individuals who have had an ACL surgically repaired six to 18 months after return to play do not appear to have aerobic capacity or strength deficits between the injured leg and uninjured leg.
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20
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Staples TJ, Do-Duc AA, Link JE, Martin JC. Emphasizing one leg facilitates single-leg training using standard cycling equipment. Scand J Med Sci Sports 2020; 30:1017-1023. [PMID: 32077131 DOI: 10.1111/sms.13638] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 01/06/2020] [Accepted: 02/17/2020] [Indexed: 11/30/2022]
Abstract
PURPOSE Single-leg cycling exercise is one of the most potent, but underutilized, stimuli for promoting peripheral muscle respiratory capacity. Special ergometers used to facilitate single-leg cycling, while maintaining biomechanics similar to double-leg cycling, are not widely available. This lack of availability of specialized ergometers may explain why single-leg cycling has not been widely implemented as standard clinical practice. Therefore, we explored the extent to which participants could emphasize one leg and de-emphasize the other to perform "single-leg emphasis cycling" using standard cycle ergometers. METHODS Sixteen athletic participants performed single-leg emphasis cycling, emphasizing each leg in separate trials, and double-leg cycling. Pedal forces and limb kinematics were collected and used to calculate joint-specific work and power at the ankle, knee, and hip. RESULTS Study participants were able to produce approximately three times as much power with their emphasized leg compared to the de-emphasized leg during single-leg emphasis cycling. Ankle plantar flexion, dorsiflexion, knee extension, and hip extension work produced during single-leg emphasis cycling did not differ from those during double-leg cycling (all P > .60). Hip and knee flexion work during single-leg emphasis cycling exhibited small but significant differences (both P < .05) from double-leg cycling. CONCLUSIONS These results demonstrate that single-leg emphasis cycling provides a convenient alternative to single-leg cycling requiring specialized ergometers, therefore, facilitating improved training in clinical and athletic populations using commonly available equipment. Further, biomechanics during single-leg emphasis cycling closely approximated double-leg cycling ensuring that training adaptations are highly applicable to double-leg cycling.
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Marillier M, Bernard AC, Vergès S, Neder JA. Locomotor Muscles in COPD: The Rationale for Rehabilitative Exercise Training. Front Physiol 2020; 10:1590. [PMID: 31992992 PMCID: PMC6971045 DOI: 10.3389/fphys.2019.01590] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 12/19/2019] [Indexed: 12/28/2022] Open
Abstract
Exercise training as part of pulmonary rehabilitation is arguably the most effective intervention to improve tolerance to physical exertion in patients with chronic obstructive pulmonary disease (COPD). Owing to the fact that exercise training has modest effects on exertional ventilation, operating lung volumes and respiratory muscle performance, improving locomotor muscle structure and function are key targets for pulmonary rehabilitation in COPD. In the current concise review, we initially discuss whether patients’ muscles are exposed to deleterious factors. After presenting corroboratory evidence on this regard (e.g., oxidative stress, inflammation, hypoxemia, inactivity, and medications), we outline their effects on muscle macro- and micro-structure and related functional properties. We then finalize by addressing the potential beneficial consequences of different training strategies on these muscle-centered outcomes. This review provides, therefore, an up-to-date outline of the rationale for rehabilitative exercise training approaches focusing on the locomotor muscles in this patient population.
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Affiliation(s)
- Mathieu Marillier
- Laboratory of Clinical Exercise Physiology, Kingston General Hospital, Queen's University, Kingston, ON, Canada
| | - Anne-Catherine Bernard
- Laboratory of Clinical Exercise Physiology, Kingston General Hospital, Queen's University, Kingston, ON, Canada
| | - Samuel Vergès
- HP2 Laboratory, INSERM, CHU Grenoble Alpes, Grenoble Alpes University, Grenoble, France
| | - J Alberto Neder
- Laboratory of Clinical Exercise Physiology, Kingston General Hospital, Queen's University, Kingston, ON, Canada
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22
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Fiorentino G, Esquinas AM, Annunziata A. Exercise and Chronic Obstructive Pulmonary Disease (COPD). ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1228:355-368. [PMID: 32342470 DOI: 10.1007/978-981-15-1792-1_24] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Systemic effects of COPD lead to cardiovascular co-morbidities, muscle wasting and osteoporosis that, in turn, lead to inactivity and physical deconditioning. This evolution has a direct influence on the health-related quality of life (HRQoL) of patients suffering from this respiratory disease. Pharmacological therapy leads to improvement in shortness of breath, but it has a limited effect on the physical deconditioning. Pulmonary rehabilitation relieves dyspnoea and fatigue, improves emotional function and enhances the sense of control that individuals have over their condition. These improvements are moderately substantial and clinically significant. Rehabilitation serves as an essential component of the management of COPD and is beneficial in improving health-related quality of life and exercise capacity.
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Affiliation(s)
- Giuseppe Fiorentino
- Division of Respiratory Physiopathology and Rehabilitation, A.O.R.N. "Dei Colli" - Monaldi Hospital, Naples, Italy
- , Salerno, Italy
| | - Antonio M Esquinas
- Intensive Care Unit, Hospital Morales Meseguer, Murcia, Spain
- Non Invasive Ventilatory Unit, Hospital Morales Meseguer, Murcia, Spain
| | - Anna Annunziata
- Division of Respiratory Physiopathology and Rehabilitation, A.O.R.N. "Dei Colli" - Monaldi Hospital, Naples, Italy
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MacInnis MJ, Skelly LE, Godkin FE, Martin BJ, Tripp TR, Tarnopolsky MA, Gibala MJ. Effect of short-term, high-intensity exercise training on human skeletal muscle citrate synthase maximal activity: single versus multiple bouts per session. Appl Physiol Nutr Metab 2019; 44:1391-1394. [PMID: 31618598 DOI: 10.1139/apnm-2019-0403] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The legs of 9 men (age 21 ± 2 years, 45 ± 4 mL/(kg·min)) were randomly assigned to complete 6 sessions of high-intensity exercise training, involving either one or four 5-min bouts of counterweighted, single-leg cycling. Needle biopsies from vastus lateralis revealed that citrate synthase maximal activity increased after training in the 4-bout group (p = 0.035) but not the 1-bout group (p = 0.10), with a significant difference between groups post-training (13%, p = 0.021). Novelty Short-term training using brief intense exercise requires multiple bouts per session to increase mitochondrial content in human skeletal muscle.
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Affiliation(s)
- Martin J MacInnis
- Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada.,Faculty of Kinesiology, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Lauren E Skelly
- Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - F Elizabeth Godkin
- Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Brian J Martin
- Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Thomas R Tripp
- Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Mark A Tarnopolsky
- Department of Pediatrics and Medicine, McMaster University, Hamilton, ON L8P 1H1, Canada
| | - Martin J Gibala
- Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1, Canada
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24
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Iannetta D, Passfield L, Qahtani A, MacInnis MJ, Murias JM. Interlimb differences in parameters of aerobic function and local profiles of deoxygenation during double-leg and counterweighted single-leg cycling. Am J Physiol Regul Integr Comp Physiol 2019; 317:R840-R851. [PMID: 31617749 DOI: 10.1152/ajpregu.00164.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
It is typically assumed that in the context of double-leg cycling, dominant (DOMLEG) and nondominant legs (NDOMLEG) have similar aerobic capacity and both contribute equally to the whole body physiological responses. However, there is a paucity of studies that have systematically investigated maximal and submaximal aerobic performance and characterized the profiles of local muscle deoxygenation in relation to leg dominance. Using counterweighted single-leg cycling, this study explored whether peak O2 consumption (V̇o2peak), maximal lactate steady-state (MLSSp), and profiles of local deoxygenation [HHb] would be different in the DOMLEG compared with the NDOMLEG. Twelve participants performed a series of double-leg and counterweighted single-leg DOMLEG and NDOMLEG ramp-exercise tests and 30-min constant-load trials. V̇o2peak was greater in the DOMLEG than in the NDOMLEG (2.87 ± 0.42 vs. 2.70 ± 0.39 L/min, P < 0.05). The difference in V̇o2peak persisted even after accounting for lean mass (P < 0.05). Similarly, MLSSp was greater in the DOMLEG than in the NDOMLEG (118 ± 31 vs. 109 ± 31 W; P < 0.05). Furthermore, the amplitude of the [HHb] signal during ramp exercise was larger in the DOMLEG than in the NDOMLEG during both double-leg (26.0 ± 8.4 vs. 20.2 ± 8.8 µM, P < 0.05) and counterweighted single-leg cycling (18.5 ± 7.9 vs. 14.9 ± 7.5 µM, P < 0.05). Additionally, the amplitudes of the [HHb] signal were highly to moderately correlated with the mode-specific V̇o2peak values (ranging from 0.91 to 0.54). These findings showed in a group of young men that maximal and submaximal aerobic capacities were greater in the DOMLEG than in the NDOMLEG and that superior peripheral adaptations of the DOMLEG may underpin these differences.NEW & NOTEWORTHY It is typically assumed that the dominant and nondominant legs contribute equally to the whole physiological responses. In this study, we found that the dominant leg achieved greater peak O2 uptake values, sustained greater power output while preserving whole body metabolic stability, and showed larger amplitudes of deoxygenation responses. These findings highlight heterogeneous aerobic capacities of the lower limbs, which have important implications when whole body physiological responses are examined.
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Affiliation(s)
- Danilo Iannetta
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Louis Passfield
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,School of Sport and Exercise Sciences, University of Kent, Canterbury, United Kingdom
| | - Ahmad Qahtani
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Martin J MacInnis
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
| | - Juan M Murias
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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25
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Cardinale DA, Larsen FJ, Lännerström J, Manselin T, Södergård O, Mijwel S, Lindholm P, Ekblom B, Boushel R. Influence of Hyperoxic-Supplemented High-Intensity Interval Training on Hemotological and Muscle Mitochondrial Adaptations in Trained Cyclists. Front Physiol 2019; 10:730. [PMID: 31258485 PMCID: PMC6587061 DOI: 10.3389/fphys.2019.00730] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 05/27/2019] [Indexed: 11/13/2022] Open
Abstract
Background: Hyperoxia (HYPER) increases O2 carrying capacity resulting in a higher O2 delivery to the working muscles during exercise. Several lines of evidence indicate that lactate metabolism, power output, and endurance are improved by HYPER compared to normoxia (NORM). Since HYPER enables a higher exercise power output compared to NORM and considering the O2 delivery limitation at exercise intensities near to maximum, we hypothesized that hyperoxic-supplemented high-intensity interval training (HIIT) would upregulate muscle mitochondrial oxidative capacity and enhance endurance cycling performance compared to training in normoxia. Methods: 23 trained cyclists, age 35.3 ± 6.4 years, body mass 75.2 ± 9.6 kg, height 179.8 ± 7.9 m, and VO2max 4.5 ± 0.7 L min-1 performed 6 weeks polarized and periodized endurance training on a cycle ergometer consisting of supervised HIIT sessions 3 days/week and additional low-intensity training 2 days/week. Participants were randomly assigned to either HYPER (FIO2 0.30; n = 12) or NORM (FIO2 0.21; n = 11) breathing condition during HIIT. Mitochondrial respiration in permeabilized fibers and isolated mitochondria together with maximal and submaximal VO2, hematological parameters, and self-paced endurance cycling performance were tested pre- and posttraining intervention. Results: Hyperoxic training led to a small, non-significant change in performance compared to normoxic training (HYPER 6.0 ± 3.7%, NORM 2.4 ± 5.0%; p = 0.073, ES = 0.32). This small, beneficial effect on the self-paced endurance cycling performance was not explained by the change in VO2max (HYPER 1.1 ± 3.8%, NORM 0.0 ± 3.7%; p = 0.55, ES = 0.08), blood volume and hemoglobin mass, mitochondrial oxidative phosphorylation capacity (permeabilized fibers: HYPER 27.3 ± 46.0%, NORM 16.5 ± 49.1%; p = 0.37, ES = 3.24 and in isolated mitochondria: HYPER 26.1 ± 80.1%, NORM 15.9 ± 73.3%; p = 0.66, ES = 0.51), or markers of mitochondrial content which were similar between groups post intervention. Conclusions: This study showed that 6 weeks hyperoxic-supplemented HIIT led to marginal gain in cycle performance in already trained cyclists without change in VO2max, blood volume, hemoglobin mass, mitochondrial oxidative phosphorylation capacity, or exercise efficiency. The underlying mechanisms for the potentially meaningful performance effects of hyperoxia training remain unexplained and may raise ethical questions for elite sport.
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Affiliation(s)
- D A Cardinale
- Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - F J Larsen
- Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - J Lännerström
- Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - T Manselin
- Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - O Södergård
- Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - S Mijwel
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - P Lindholm
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - B Ekblom
- Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - R Boushel
- School of Kinesiology, Faculty of Education, University of British Columbia, Vancouver, BC, Canada
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26
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Mølmen KS, Hallén J, Rud B. Peripheral adaptations to endurance training—Effect of active muscle mass. TRANSLATIONAL SPORTS MEDICINE 2019. [DOI: 10.1002/tsm2.87] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Knut Sindre Mølmen
- Department of Physical Performance Norwegian School of Sport Sciences Oslo Norway
- Section for Health and Exercise Physiology Inland Norway University of Applied Sciences Lillehammer Norway
| | - Jostein Hallén
- Department of Physical Performance Norwegian School of Sport Sciences Oslo Norway
| | - Bjarne Rud
- Department of Physical Performance Norwegian School of Sport Sciences Oslo Norway
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27
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GORDON NICOLE, ABBISS CHRISR, MAIORANA ANDREWJ, JAMES ANTHONYP, CLARK KARIN, MARSTON KIERANJ, PEIFFER JEREMIAHJ. High-Intensity Single-Leg Cycling Improves Cardiovascular Disease Risk Factor Profile. Med Sci Sports Exerc 2019; 51:2234-2242. [DOI: 10.1249/mss.0000000000002053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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28
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Gordon N, Abbiss CR, Maiorana AJ, Peiffer JJ. Single-leg cycling increases limb-specific blood flow without concurrent increases in normalised power output when compared with double-leg cycling in healthy middle-aged adults. Eur J Sport Sci 2019; 20:202-210. [PMID: 31072224 DOI: 10.1080/17461391.2019.1617789] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
This study examined the acute performance, cardiovascular and local muscular responses to perceived exertion-based high-intensity interval exercise using either double- or single-leg cycling. Fifteen healthy middle-aged adults completed, on separate occasions, ten 30-s double-leg intervals interspersed with 60 s passive recovery and twenty (ten with each leg) 30-s single-leg intervals interspersed with 60 s passive recovery. Impedance cardiography, blood pressure, muscle oxygenation and total haemoglobin content (near-infrared spectroscopy), oxygen consumption and power output were measured throughout each session. Normalised to the lean mass used during each trial, single-leg cycling resulted in lower power output (single-leg: 8.92 ± 1.74 W kg-1 and double-leg: 10.41 ± 3.22 W kg-1; p < 0.05) but greater oxygen consumption (single-leg: 103 ± 11 mL kg-1 min-1 and double-leg: 84 ± 21 mL kg-1 min-1; p < 0.01) and cardiac output (single-leg: 1407 ± 334 mL kg-1 min-1 and double-leg: 850 ± 222 mL kg-1 min-1; p < 0.01), compared with double-leg cycling. Mean arterial pressure (double-leg: 108 ± 11 mmHg and single-leg: 102 ± 10 mmHg), change in total haemoglobin content (double-leg: 8.76 ± 10.65 µM cm s-1 and single-leg: 13.42 ± 4.10 µM cm s-1) and change in tissue oxygenation index (double-leg: -4.51 ± 3.56% and single-leg: -3.97 ± 3.91%) were not different between double-leg and single-leg cycling. When compared to double-leg cycling, single-leg cycling elicited a higher cardiac output relative to the lean mass, but this did not result in greater power output. The dissociation between blood availability and power output is consistent with an ageing model characterised by a decrease in local oxygen delivery and distribution capability.
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Affiliation(s)
- Nicole Gordon
- Discipline of Exercise Science, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, Australia
| | - Chris R Abbiss
- Centre for Exercise and Sport Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia
| | - Andrew J Maiorana
- School of Physiotherapy and Exercise Science, Curtin University, Bentley, Australia.,Allied Health Department, Fiona Stanley Hospital, Murdoch, Australia
| | - Jeremiah J Peiffer
- Discipline of Exercise Science, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, Australia
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29
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Pickett CW, Nosaka K, Zois J, Hopkins WG, Blazevich AJ. Maximal Upper-Body Strength and Oxygen Uptake Are Associated With Performance in High-Level 200-m Sprint Kayakers. J Strength Cond Res 2019; 32:3186-3192. [PMID: 29283928 DOI: 10.1519/jsc.0000000000002398] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Pickett, CW, Nosaka, K, Zois, J, Hopkins, WG, and Blazevich, AJ. Maximal upper-body strength and oxygen uptake are associated with performance in high-level 200-m sprint kayakers. J Strength Cond Res 32(11): 3186-3192, 2018-Current training and monitoring methods in sprint kayaking are based on the premise that upper-body muscular strength and aerobic power are both important for performance, but limited evidence exists to support this premise in high-level athletes. Relationships between measures of strength, maximal oxygen uptake (V[Combining Dot Above]O2max), and 200-m race times in kayakers competing at national-to-international levels were examined. Data collected from Australian Canoeing training camps and competitions for 7 elite, 7 national, and 8 club-level male sprint kayakers were analyzed for relationships between maximal isoinertial strength (3 repetition maximum bench press, bench row, chin-up, and deadlift), V[Combining Dot Above]O2max on a kayak ergometer, and 200-m race time. Correlations between race time and bench press, bench row, chin-up, and V[Combining Dot Above]O2max were -0.80, -0.76, -0.73, -0.02, and 0.71, respectively (90% confidence limits ∼±0.17). The multiple correlation coefficient for 200-m race time with bench press and V[Combining Dot Above]O2max was 0.84. Errors in prediction of 200-m race time in regression analyses were extremely large (∼4%) in relation to the smallest important change of 0.3%. However, from the slopes of the regressions, the smallest important change could be achieved with a 1.4% (±0.5%) change in bench-press strength and a 0.9% (±0.5%) change in V[Combining Dot Above]O2max. Substantial relationships were found between upper-body strength or aerobic power and 200-m performances. These measures may not accurately predict individual performance times, but would be practicable for talent identification purposes. Training aimed at improving upper-body strength or aerobic power in lower performing athletes could also enhance the performance in 200-m kayak sprints.
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Affiliation(s)
- Craig W Pickett
- Center for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
| | - Kazunori Nosaka
- Center for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
| | - James Zois
- ISEAL College of Sport and Exercise Science, Victoria University, Footscray Park, Australia
| | - Will G Hopkins
- ISEAL College of Sport and Exercise Science, Victoria University, Footscray Park, Australia
| | - Anthony J Blazevich
- Center for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
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30
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Training-Induced Changes in Mitochondrial Content and Respiratory Function in Human Skeletal Muscle. Sports Med 2018; 48:1809-1828. [PMID: 29934848 DOI: 10.1007/s40279-018-0936-y] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A sedentary lifestyle has been linked to a number of metabolic disorders that have been associated with sub-optimal mitochondrial characteristics and an increased risk of premature death. Endurance training can induce an increase in mitochondrial content and/or mitochondrial functional qualities, which are associated with improved health and well-being and longer life expectancy. It is therefore important to better define how manipulating key parameters of an endurance training intervention can influence the content and functionality of the mitochondrial pool. This review focuses on mitochondrial changes taking place following a series of exercise sessions (training-induced mitochondrial adaptations), providing an in-depth analysis of the effects of exercise intensity and training volume on changes in mitochondrial protein synthesis, mitochondrial content and mitochondrial respiratory function. We provide evidence that manipulation of different exercise training variables promotes specific and diverse mitochondrial adaptations. Specifically, we report that training volume may be a critical factor affecting changes in mitochondrial content, whereas relative exercise intensity is an important determinant of changes in mitochondrial respiratory function. As a consequence, a dissociation between training-induced changes in mitochondrial content and mitochondrial respiratory function is often observed. We also provide evidence that exercise-induced changes are not necessarily predictive of training-induced adaptations, we propose possible explanations for the above discrepancies and suggestions for future research.
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31
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Cardinale DA, Larsen FJ, Schiffer TA, Morales-Alamo D, Ekblom B, Calbet JAL, Holmberg HC, Boushel R. Superior Intrinsic Mitochondrial Respiration in Women Than in Men. Front Physiol 2018; 9:1133. [PMID: 30174617 PMCID: PMC6108574 DOI: 10.3389/fphys.2018.01133] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Accepted: 07/30/2018] [Indexed: 11/25/2022] Open
Abstract
Sexual dimorphism is apparent in humans, however, to date no studies have investigated mitochondrial function focusing on intrinsic mitochondrial respiration (i.e., mitochondrial respiration for a given amount of mitochondrial protein) and mitochondrial oxygen affinity (p50mito) in relation to biological sex in human. A skeletal muscle biopsy was donated by nine active women, and ten men matched for maximal oxygen consumption (VO2max) and by nine endurance trained men. Intrinsic mitochondrial respiration, assessed in isolated mitochondria, was higher in women compared to men when activating complex I (CIP) and complex I+II (CI+IIP) (p < 0.05), and was similar to trained men (CIP, p = 0.053; CI+IIP, p = 0.066). Proton leak and p50mito were higher in women compared to men independent of VO2max. In conclusion, significant novel differences in mitochondrial oxidative function, intrinsic mitochondrial respiration and p50mito exist between women and men. These findings may represent an adaptation in the oxygen cascade in women to optimize muscle oxygen uptake to compensate for a lower oxygen delivery during exercise.
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Affiliation(s)
- Daniele A Cardinale
- Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Filip J Larsen
- Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Tomas A Schiffer
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - David Morales-Alamo
- Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas, Spain.,Research Institute of Biomedical and Health Sciences (IUIBS), Las Palmas de Gran Canaria, Gran Canaria, Spain
| | - Björn Ekblom
- Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Jose A L Calbet
- Department of Physical Education, University of Las Palmas de Gran Canaria, Las Palmas, Spain.,Research Institute of Biomedical and Health Sciences (IUIBS), Las Palmas de Gran Canaria, Gran Canaria, Spain.,School of Kinesiology, Faculty of Education, The University of British Columbia, Vancouver, BC, Canada
| | - Hans-Christer Holmberg
- School of Kinesiology, Faculty of Education, The University of British Columbia, Vancouver, BC, Canada.,Swedish Winter Sports Research Centre, Department of Health Sciences, Mid Sweden University, Östersund, Sweden
| | - Robert Boushel
- School of Kinesiology, Faculty of Education, The University of British Columbia, Vancouver, BC, Canada
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32
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Lipski M, Abbiss CR, Nosaka K. Oxygen consumption, rate of perceived exertion and enjoyment in high-intensity interval eccentric cycling. Eur J Sport Sci 2018; 18:1390-1397. [PMID: 30041569 DOI: 10.1080/17461391.2018.1498131] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The objectives of this article are to compare oxygen consumption (VO2) and perceptual responses between continuous and interval eccentric cycling protocols in order to test the hypothesis that metabolic demand and enjoyment would be greater for interval than continuous eccentric cycling protocols. Eleven recreationally active men (n = 9) and women (32.6 ± 9.4 years) performed a concentric cycling test to determine peak power output (PPO) followed by five eccentric cycling protocols on separate occasions: continuous eccentric cycling at 60% of PPO for 20 min at 60 rpm (CONT20@60%) and 13.2 min at 90 rpm (CONT13@60%), 4 × 4 min at 75% of PPO with 2-min rest (INT4×4@75%), 12 × 1 min at 100% of PPO with 1-min rest (INT1×12@100%) and 10 × 1 min at 150% of PPO with 1-min rest (INT1×10@150%). Gas exchange and power output were recorded continuously, and rate of perceived exertion (RPE) and enjoyment were assessed after each exercise. Total VO2 including the rest periods was the greatest (p < 0.0001) during INT1×10@150% (382 ± 73 ml kg-1) and lowest (p < 0.0001) during CONT13@60% (146 ± 27 ml kg-1). Total VO2 during INT1×12@100% (312 ± 59 ml kg-1) was greater (p < 0.0001) than CONT20@60% (246 ± 63 ml kg-1) and INT4×4@75% (257 ± 42 ml kg-1). RPE was greater (p < 0.0001) after INT1×10@150% (17 ± 2) than other conditions, but perceived enjoyment was not significantly different between protocols. It was concluded that the interval protocols increased metabolic demand without increasing RPE and enjoyment. It appears that high-intensity interval protocols can be used in eccentric cycling prescription.
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Affiliation(s)
- Marcin Lipski
- a Centre for Exercise and Sport Science Research, School of Medical and Health Science, Edith Cowan University , Joondalup , Australia
| | - Chris R Abbiss
- a Centre for Exercise and Sport Science Research, School of Medical and Health Science, Edith Cowan University , Joondalup , Australia
| | - Kazunori Nosaka
- a Centre for Exercise and Sport Science Research, School of Medical and Health Science, Edith Cowan University , Joondalup , Australia
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33
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Gordon N, Abbiss CR, Ihsan M, Maiorana AJ, Peiffer JJ. Active and Inactive Leg Hemodynamics during Sequential Single-Leg Interval Cycling. Med Sci Sports Exerc 2018; 50:1297-1304. [PMID: 29324474 DOI: 10.1249/mss.0000000000001553] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Leg order during sequential single-leg cycling (i.e., exercising both legs independently within a single session) may affect local muscular responses potentially influencing adaptations. This study examined the cardiovascular and skeletal muscle hemodynamic responses during double-leg and sequential single-leg cycling. METHODS Ten young healthy adults (28 ± 6 yr) completed six 1-min double-leg intervals interspersed with 1 min of passive recovery and, on a separate occasion, 12 (six with one leg followed by six with the other leg) 1-min single-leg intervals interspersed with 1 min of passive recovery. Oxygen consumption, heart rate, blood pressure, muscle oxygenation, muscle blood volume, and power output were measured throughout each session. RESULTS Oxygen consumption, heart rate, and power output were not different between sets of single-leg intervals, but the average of both sets was lower than the double-leg intervals. Mean arterial pressure was higher during double-leg compared with sequential single-leg intervals (115 ± 9 vs 104 ± 9 mm Hg, P < 0.05) and higher during the initial compared with second set of single-leg intervals (108 ± 10 vs 101 ± 10 mm Hg, P < 0.05). The increase in muscle blood volume from baseline was similar between the active single leg and the double leg (267 ± 150 vs 214 ± 169 μM·cm, P = 0.26). The pattern of change in muscle blood volume from the initial to second set of intervals was significantly different (P < 0.05) when the leg was active in the initial (-52.3% ± 111.6%) compared with second set (65.1% ± 152.9%). CONCLUSIONS These data indicate that the order in which each leg performs sequential single-leg cycling influences the local hemodynamic responses, with the inactive muscle influencing the stimulus experienced by the contralateral leg.
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Affiliation(s)
- Nicole Gordon
- School of Psychology and Exercise Science, Murdoch University, Murdoch, AUSTRALIA
| | - Chris R Abbiss
- Centre for Exercise and Sport Science Research, School of Exercise and Health Science, Edith Cowan University, Joondalup, AUSTRALIA
| | - Mohammed Ihsan
- Centre for Exercise and Sport Science Research, School of Exercise and Health Science, Edith Cowan University, Joondalup, AUSTRALIA.,Athlete Health and Performance Research Centre, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, QATAR
| | - Andrew J Maiorana
- School of Physiotherapy and Exercise Science, Curtin University, Bentley, AUSTRALIA.,Allied Health Department, Fiona Stanley Hospital, Murdoch, AUSTRALIA
| | - Jeremiah J Peiffer
- School of Psychology and Exercise Science, Murdoch University, Murdoch, AUSTRALIA
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Physiological responses to incremental, interval, and continuous counterweighted single-leg and double-leg cycling at the same relative intensities. Eur J Appl Physiol 2017; 117:1423-1435. [DOI: 10.1007/s00421-017-3635-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 05/05/2017] [Indexed: 12/20/2022]
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35
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The Impact of Heat Exposure and Sleep Restriction on Firefighters' Work Performance and Physiology during Simulated Wildfire Suppression. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14020180. [PMID: 28208688 PMCID: PMC5334734 DOI: 10.3390/ijerph14020180] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 02/05/2017] [Accepted: 02/06/2017] [Indexed: 11/16/2022]
Abstract
This study was designed to examine the effects of ambient heat on firefighters' physical task performance, and physiological and perceptual responses when sleep restricted during simulated wildfire conditions. Thirty firefighters were randomly allocated to the sleep restricted (n = 17, SR; 19 °C, 4-h sleep opportunity) or hot and sleep restricted (n = 13, HOT + SR; 33 °C, 4-h sleep opportunity) condition. Firefighters performed two days of simulated, intermittent, self-paced work circuits comprising six firefighting tasks. Heart rate, and core temperature were measured continuously. After each task, firefighters reported their rating of perceived exertion and thermal sensation. Effort sensation was also reported after each work circuit. Fluids were consumed ad libitum. Urine volume and urine specific gravity were analysed. Sleep was monitored using polysomnography. There were no differences between the SR and HOT + SR groups in firefighters' physiological responses, hydration status, ratings of perceived exertion, motivation, and four of the six firefighting tasks (charged hose advance, rake, hose rolling, static hose hold). Black out hose and lateral repositioning were adversely affected in the HOT + SR group. Working in hot conditions did not appear to consistently impair firefighters work performance, physiology, and perceptual responses. Future research should determine whether such findings remain true when individual tasks are performed over longer durations.
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36
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MacInnis MJ, McGlory C, Gibala MJ, Phillips SM. Investigating human skeletal muscle physiology with unilateral exercise models: when one limb is more powerful than two. Appl Physiol Nutr Metab 2017; 42:563-570. [PMID: 28177712 DOI: 10.1139/apnm-2016-0645] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Direct sampling of human skeletal muscle using the needle biopsy technique can facilitate insight into the biochemical and histological responses resulting from changes in exercise or feeding. However, the muscle biopsy procedure is invasive, and analyses are often expensive, which places pragmatic restraints on sample sizes. The unilateral exercise model can serve to increase statistical power and reduce the time and cost of a study. With this approach, 2 limbs of a participant are randomized to 1 of 2 treatments that can be applied almost concurrently or sequentially depending on the nature of the intervention. Similar to a typical repeated measures design, comparisons are made within participants, which increases statistical power by reducing the amount of between-person variability. A washout period is often unnecessary, reducing the time needed to complete the experiment and the influence of potential confounding variables such as habitual diet, activity, and sleep. Variations of the unilateral exercise model have been employed to investigate the influence of exercise, diet, and the interaction between the 2, on a wide range of variables including mitochondrial content, capillary density, and skeletal muscle hypertrophy. Like any model, unilateral exercise has some limitations: it cannot be used to study variables that potentially transfer across limbs, and it is generally limited to exercises that can be performed in pairs of treatments. Where appropriate, however, the unilateral exercise model can yield robust, well-controlled investigations of skeletal muscle responses to a wide range of interventions and conditions including exercise, dietary manipulation, and disuse or immobilization.
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Affiliation(s)
- Martin J MacInnis
- Department of Kinesiology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada.,Department of Kinesiology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Chris McGlory
- Department of Kinesiology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada.,Department of Kinesiology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Martin J Gibala
- Department of Kinesiology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada.,Department of Kinesiology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
| | - Stuart M Phillips
- Department of Kinesiology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada.,Department of Kinesiology, McMaster University, 1280 Main Street West, Hamilton, ON L8S 4K1, Canada
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MacInnis MJ, Gibala MJ. Physiological adaptations to interval training and the role of exercise intensity. J Physiol 2016; 595:2915-2930. [PMID: 27748956 DOI: 10.1113/jp273196] [Citation(s) in RCA: 539] [Impact Index Per Article: 67.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 10/11/2016] [Indexed: 12/18/2022] Open
Abstract
Interval exercise typically involves repeated bouts of relatively intense exercise interspersed by short periods of recovery. A common classification scheme subdivides this method into high-intensity interval training (HIIT; 'near maximal' efforts) and sprint interval training (SIT; 'supramaximal' efforts). Both forms of interval training induce the classic physiological adaptations characteristic of moderate-intensity continuous training (MICT) such as increased aerobic capacity (V̇O2 max ) and mitochondrial content. This brief review considers the role of exercise intensity in mediating physiological adaptations to training, with a focus on the capacity for aerobic energy metabolism. With respect to skeletal muscle adaptations, cellular stress and the resultant metabolic signals for mitochondrial biogenesis depend largely on exercise intensity, with limited work suggesting that increases in mitochondrial content are superior after HIIT compared to MICT, at least when matched-work comparisons are made within the same individual. It is well established that SIT increases mitochondrial content to a similar extent to MICT despite a reduced exercise volume. At the whole-body level, V̇O2 max is generally increased more by HIIT than MICT for a given training volume, whereas SIT and MICT similarly improve V̇O2 max despite differences in training volume. There is less evidence available regarding the role of exercise intensity in mediating changes in skeletal muscle capillary density, maximum stroke volume and cardiac output, and blood volume. Furthermore, the interactions between intensity and duration and frequency have not been thoroughly explored. While interval training is clearly a potent stimulus for physiological remodelling in humans, the integrative response to this type of exercise warrants further attention, especially in comparison to traditional endurance training.
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Affiliation(s)
- Martin J MacInnis
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Martin J Gibala
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
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MacInnis MJ, Zacharewicz E, Martin BJ, Haikalis ME, Skelly LE, Tarnopolsky MA, Murphy RM, Gibala MJ. Superior mitochondrial adaptations in human skeletal muscle after interval compared to continuous single-leg cycling matched for total work. J Physiol 2016; 595:2955-2968. [PMID: 27396440 DOI: 10.1113/jp272570] [Citation(s) in RCA: 141] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 07/01/2016] [Indexed: 12/22/2022] Open
Abstract
KEY POINTS A classic unresolved issue in human integrative physiology involves the role of exercise intensity, duration and volume in regulating skeletal muscle adaptations to training. We employed counterweighted single-leg cycling as a unique within-subject model to investigate the role of exercise intensity in promoting training-induced increases in skeletal muscle mitochondrial content. Six sessions of high-intensity interval training performed over 2 weeks elicited greater increases in citrate synthase maximal activity and mitochondrial respiration compared to moderate-intensity continuous training matched for total work and session duration. These data suggest that exercise intensity, and/or the pattern of contraction, is an important determinant of exercise-induced skeletal muscle remodelling in humans. ABSTRACT We employed counterweighted single-leg cycling as a unique model to investigate the role of exercise intensity in human skeletal muscle remodelling. Ten young active men performed unilateral graded-exercise tests to measure single-leg V̇O2, peak and peak power (Wpeak ). Each leg was randomly assigned to complete six sessions of high-intensity interval training (HIIT) [4 × (5 min at 65% Wpeak and 2.5 min at 20% Wpeak )] or moderate-intensity continuous training (MICT) (30 min at 50% Wpeak ), which were performed 10 min apart on each day, in an alternating order. The work performed per session was matched for MICT (143 ± 8.4 kJ) and HIIT (144 ± 8.5 kJ, P > 0.05). Post-training, citrate synthase (CS) maximal activity (10.2 ± 0.8 vs. 8.4 ± 0.9 mmol kg protein-1 min-1 ) and mass-specific [pmol O2 •(s•mg wet weight)-1 ] oxidative phosphorylation capacities (complex I: 23.4 ± 3.2 vs. 17.1 ± 2.8; complexes I and II: 58.2 ± 7.5 vs. 42.2 ± 5.3) were greater in HIIT relative to MICT (interaction effects, P < 0.05); however, mitochondrial function [i.e. pmol O2 •(s•CS maximal activity)-1 ] measured under various conditions was unaffected by training (P > 0.05). In whole muscle, the protein content of COXIV (24%), NDUFA9 (11%) and mitofusin 2 (MFN2) (16%) increased similarly across groups (training effects, P < 0.05). Cytochrome c oxidase subunit IV (COXIV) and NADH:ubiquinone oxidoreductase subunit A9 (NDUFA9) were more abundant in type I than type II fibres (P < 0.05) but training did not increase the content of COXIV, NDUFA9 or MFN2 in either fibre type (P > 0.05). Single-leg V̇O2, peak was also unaffected by training (P > 0.05). In summary, single-leg cycling performed in an interval compared to a continuous manner elicited superior mitochondrial adaptations in human skeletal muscle despite equal total work.
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Affiliation(s)
- Martin J MacInnis
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Evelyn Zacharewicz
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Brian J Martin
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Maria E Haikalis
- Department of Pediatrics and Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Lauren E Skelly
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
| | - Mark A Tarnopolsky
- Department of Pediatrics and Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Robyn M Murphy
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Martin J Gibala
- Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada
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Bini RR, Jacques TC, Carpes FP, Vaz MA. Effectiveness of pedalling retraining in reducing bilateral pedal force asymmetries. J Sports Sci 2016; 35:1336-1341. [PMID: 27476549 DOI: 10.1080/02640414.2016.1215505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Previous studies have been limited to describe asymmetries during pedalling and suggest possible repercussion on performance and/or injury risks. However, few studies have presented strategies to mitigate asymmetries. The purpose of this study was to assess the effectiveness of a pedalling retraining intervention to reduce bilateral pedal force asymmetries. Twenty cyclists were assessed and 10 enrolled in a pedalling retraining method receiving visual and verbal feedback of pedal forces. The asymmetry index was computed for comparison of bilateral peak pedal forces and used during retraining (12 trials at 70% of peak power). Significantly larger asymmetry was observed for asymmetrical cyclists at the first three trials (P < 0.01 and ES = 1.39), which was reduced when post-retraining was compared to measures from symmetrical cyclists (P = 0.69 and ES = 0.18). Cyclists with larger asymmetry (>20%) in bilateral pedal forces reduce their asymmetries using sessions of pedalling retraining and achieve asymmetry indices similar to symmetrical cyclists.
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Affiliation(s)
- Rodrigo R Bini
- a School of Physical Education of the Army , Centre of Physical Training of the Army , Rio de Janeiro , Brazil
| | - Tiago C Jacques
- b Exercise Research Laboratory , Federal University of Rio Grande do Sul , Porto Alegre , Brazil
| | - Felipe P Carpes
- c Laboratory of Neuromechanics , Federal University of Pampa , Uruguaiana , Brazil
| | - Marco A Vaz
- b Exercise Research Laboratory , Federal University of Rio Grande do Sul , Porto Alegre , Brazil
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Role of Ratings of Perceived Exertion during Self-Paced Exercise: What are We Actually Measuring? Sports Med 2016; 45:1235-1243. [PMID: 26054383 DOI: 10.1007/s40279-015-0344-5] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Ratings of perceived exertion (RPE) and effort are considered extremely important in the regulation of intensity during self-paced physical activity. While effort and exertion are slightly different constructs, these terms are often used interchangeably within the literature. The development of perceptions of both effort and exertion is a complicated process involving numerous neural processes occurring in various regions within the brain. It is widely accepted that perceptions of effort are highly dependent on efferent copies of central drive which are sent from motor to sensory regions of the brain. Additionally, it has been suggested that perceptions of effort and exertion are integrated based on the balance between corollary discharge and actual afferent feedback; however, the involvement of peripheral afferent sensory feedback in the development of such perceptions has been debated. As such, this review examines the possible difference between effort and exertion, and the implications of such differences in understanding the role of such perceptions in the regulation of pace during exercise.
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Handcycling: training effects of a specific dose of upper body endurance training in females. Eur J Appl Physiol 2016; 116:1387-94. [PMID: 27222003 DOI: 10.1007/s00421-016-3395-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 05/14/2016] [Indexed: 10/21/2022]
Abstract
PURPOSE This study aims to evaluate a handcycling training protocol based on ACSM guidelines in a well-controlled laboratory setting. Training responses of a specific dose of handcycling training were quantified in a homogeneous female subject population to obtain a more in depth understanding of physiological mechanisms underlying adaptations in upper body training. METHODS 22 female able-bodied participants were randomly divided in a training (T) and control group (C). T received 7-weeks of handcycling training, 3 × 30 min/week at 65 % heart rate reserve (HRR). An incremental handcycling test was used to determine local, exercise-specific adaptations. An incremental cycling test was performed to determine non-exercise-specific central/cardiovascular adaptations. Peak oxygen uptake (peakVO2), heart rate (peakHR) and power output (peakPO) were compared between T and C before and after training. RESULTS T completed the training sessions at 65 ± 3 % HRR, at increasing power output (59.4 ± 8.2 to 69.5 ± 8.9 W) over the training program. T improved on handcycling peakVO2 (+18.1 %), peakPO (+31.9 %), and peakHR (+4.0 %). No improvements were found in cycling parameters. CONCLUSION Handcycling training led to local, exercise-specific improvements in upper body parameters. Results could provide input for the design of effective evidence-based training programs specifically aimed at upper body endurance exercise in females.
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Wright RL. Positive Pacing Strategies Are Utilized by Elite Male and Female Para-cyclists in Short Time Trials in the Velodrome. Front Physiol 2016; 6:425. [PMID: 26834643 PMCID: PMC4716664 DOI: 10.3389/fphys.2015.00425] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 12/24/2015] [Indexed: 11/22/2022] Open
Abstract
In para-cycling, competitors are classed based on functional impairment resulting in cyclists with neurological and locomotor impairments competing against each other. In Paralympic competition, classes are combined by using a factoring adjustment to race times to produce the overall medallists. Pacing in short-duration track cycling events is proposed to utilize an “all-out” strategy in able-bodied competition. However, pacing in para-cycling may vary depending on the level of impairment. Analysis of the pacing strategies employed by different classification groups may offer scope for optimal performance; therefore, this study investigated the pacing strategy adopted during the 1-km time trial (TT) and 500-m TT in elite C1 to C3 para-cyclists and able-bodied cyclists. Total times and intermediate split times (125-m intervals; measured to 0.001 s) were obtained from the C1-C3 men's 1-km TT (n = 28) and women's 500-m TT (n = 9) from the 2012 Paralympic Games and the men's 1-km TT (n = 19) and women's 500-m TT (n = 12) from the 2013 UCI World Track Championships from publically available video. Split times were expressed as actual time, factored time (for the para-cyclists) and as a percentage of total time. A two-way analysis of variance was used to investigate differences in split times between the different classifications and the able-bodied cyclists in the men's 1-km TT and between the para-cyclists and able-bodied cyclists in the women's 500-m TT. The importance of position at the first split was investigated with Kendall's Tau-b correlation. The first 125-m split time was the slowest for all cyclists, representing the acceleration phase from a standing start. C2 cyclists were slowest at this 125-m split, probably due to a combination of remaining seated in this acceleration phase and a high proportion of cyclists in this group being trans-femoral amputees. Not all cyclists used aero-bars, preferring to use drop, flat or bullhorn handlebars. Split times increased in the later stages of the race, demonstrating a positive pacing strategy. In the shorter women's 500-m TT, rank at the first split was more strongly correlated with final position than in the longer men's 1-km TT. In conclusion, a positive pacing strategy was adopted by the different para-cycling classes.
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Affiliation(s)
- Rachel L Wright
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham Birmingham, UK
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Bini RR, Jacques TC, Lanferdini FJ, Vaz MA. Comparison of kinetics, kinematics, and electromyography during single-leg assisted and unassisted cycling. J Strength Cond Res 2016; 29:1534-41. [PMID: 25872025 DOI: 10.1519/jsc.0000000000000905] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
To use single-leg cycling training for varying populations, it is important to understand whether a counterweight attached to the contralateral crank during single-leg cycling drills replicates the effects of the opposite leg in the ipsilateral leg. Therefore, we compared single-leg assisted cycling using a counterweight on the contralateral crank for joint kinetics, kinematics, and lower-limb muscle activation. Fourteen healthy nonathletes performed 2 bilateral cycling trials (240 ± 23 W and 90 ± 2 rpm) and 2 single-leg trials (120 ± 11 W and 90 ± 2 rpm) for measurements of pedal force, joint kinematics, and muscle activation of their right lower limb. For 1 single-leg trial, a custom-made adaptor was used to attach 10 kg of weight to the contralateral leg. Total force applied on the pedal, pedal force effectiveness, the mean joint angles and range of motion, mechanical work at the crank, hip, knee, and ankle joints, electromyography, pedaling cadence, and right crank mechanical work were assessed. Biceps femoris (87%), vastus lateralis (15%), rectus femoris (57%), tibialis anterior (57%), and gastrocnemius medialis (12%) activations were larger in the single-leg assisted trial compared with the bilateral trial. Lower total pedal force (17%) and increased index of effectiveness (16%) also indicate mechanical differences in single-leg cycling using a counterweight on the contralateral crank than conventional bilateral cycling. Single-leg assisted training should be used with caution because of potential differences in muscle recruitment and pedaling kinetics compared with bilateral cycling.
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Affiliation(s)
- Rodrigo R Bini
- 1School of Physical Education of the Army, Center of Physical Training of the Army, Rio de Janeiro, Brazil; and 2Exercise Research Laboratory, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
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Pageaux B, Angius L, Hopker JG, Lepers R, Marcora SM. Central alterations of neuromuscular function and feedback from group III-IV muscle afferents following exhaustive high-intensity one-leg dynamic exercise. Am J Physiol Regul Integr Comp Physiol 2015; 308:R1008-20. [PMID: 25855308 DOI: 10.1152/ajpregu.00280.2014] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 04/07/2015] [Indexed: 11/22/2022]
Abstract
The aims of this investigation were to describe the central alterations of neuromuscular function induced by exhaustive high-intensity one-leg dynamic exercise (OLDE, study 1) and to indirectly quantify feedback from group III-IV muscle afferents via muscle occlusion (MO, study 2) in healthy adult male humans. We hypothesized that these central alterations and their recovery are associated with changes in afferent feedback. Both studies consisted of two time-to-exhaustion tests at 85% peak power output. In study 1, voluntary activation level (VAL), M-wave, cervicomedullary motor evoked potential (CMEP), motor evoked potential (MEP), and MEP cortical silent period (CSP) of the knee extensor muscles were measured. In study 2, mean arterial pressure (MAP) and leg muscle pain were measured during MO. Measurements were performed preexercise, at exhaustion, and after 3 min recovery. Compared with preexercise values, VAL was lower at exhaustion (-13 ± 13%, P < 0.05) and after 3 min of recovery (-6 ± 6%, P = 0.05). CMEP area/M area was lower at exhaustion (-38 ± 13%, P < 0.01) and recovered after 3 min. MEP area/M area was higher at exhaustion (+25 ± 27%, P < 0.01) and after 3 min of recovery (+17 ± 20%, P < 0.01). CSP was higher (+19 ± 9%, P < 0.01) only at exhaustion and recovered after 3 min. Markers of afferent feedback (MAP and leg muscle pain during MO) were significantly higher only at exhaustion. These findings suggest that the alterations in spinal excitability and CSP induced by high-intensity OLDE are associated with an increase in afferent feedback at exhaustion, whereas central fatigue does not fully recover even when significant afferent feedback is no longer present.
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Affiliation(s)
- Benjamin Pageaux
- Endurance Research Group, School of Sport & Exercise Sciences, University of Kent, Chatham, United Kingdom; and
| | - Luca Angius
- Endurance Research Group, School of Sport & Exercise Sciences, University of Kent, Chatham, United Kingdom; and
| | - James G Hopker
- Endurance Research Group, School of Sport & Exercise Sciences, University of Kent, Chatham, United Kingdom; and
| | - Romuald Lepers
- Laboratoire Institut national de la santé et de la recherche médical U1093, Université de Bourgogne, Faculté des Sciences du Sports, UFR STAPS, Dijon, France
| | - Samuele M Marcora
- Endurance Research Group, School of Sport & Exercise Sciences, University of Kent, Chatham, United Kingdom; and
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Vincent G, Ferguson SA, Tran J, Larsen B, Wolkow A, Aisbett B. Sleep restriction during simulated wildfire suppression: effect on physical task performance. PLoS One 2015; 10:e0115329. [PMID: 25615988 PMCID: PMC4304821 DOI: 10.1371/journal.pone.0115329] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 11/21/2014] [Indexed: 11/26/2022] Open
Abstract
Objectives To examine the effects of sleep restriction on firefighters’ physical task performance during simulated wildfire suppression. Methods Thirty-five firefighters were matched and randomly allocated to either a control condition (8-hour sleep opportunity, n = 18) or a sleep restricted condition (4-hour sleep opportunity, n = 17). Performance on physical work tasks was evaluated across three days. In addition, heart rate, core temperature, and worker activity were measured continuously. Rate of perceived and exertion and effort sensation were evaluated during the physical work periods. Results There were no differences between the sleep-restricted and control groups in firefighters’ task performance, heart rate, core temperature, or perceptual responses during self-paced simulated firefighting work tasks. However, the sleep-restricted group were less active during periods of non-physical work compared to the control group. Conclusions Under self-paced work conditions, 4 h of sleep restriction did not adversely affect firefighters’ performance on physical work tasks. However, the sleep-restricted group were less physically active throughout the simulation. This may indicate that sleep-restricted participants adapted their behaviour to conserve effort during rest periods, to subsequently ensure they were able to maintain performance during the firefighter work tasks. This work contributes new knowledge to inform fire agencies of firefighters’ operational capabilities when their sleep is restricted during multi-day wildfire events. The work also highlights the need for further research to explore how sleep restriction affects physical performance during tasks of varying duration, intensity, and complexity.
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Affiliation(s)
- Grace Vincent
- Centre for Physical Activity and Nutrition Research, Deakin University, Burwood, 3125, Australia
- Bushfire Co-Operative Research Centre, East Melbourne, 3002, Australia
- * E-mail:
| | - Sally A. Ferguson
- Bushfire Co-Operative Research Centre, East Melbourne, 3002, Australia
- Central Queensland University, Appleton Institute, Wayville, 5034, Australia
| | - Jacqueline Tran
- Centre for Exercise and Sport Science, Deakin University, Burwood, 3125, Australia
| | - Brianna Larsen
- Centre for Physical Activity and Nutrition Research, Deakin University, Burwood, 3125, Australia
- Bushfire Co-Operative Research Centre, East Melbourne, 3002, Australia
| | - Alexander Wolkow
- Centre for Physical Activity and Nutrition Research, Deakin University, Burwood, 3125, Australia
- Bushfire Co-Operative Research Centre, East Melbourne, 3002, Australia
| | - Brad Aisbett
- Centre for Physical Activity and Nutrition Research, Deakin University, Burwood, 3125, Australia
- Bushfire Co-Operative Research Centre, East Melbourne, 3002, Australia
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Puype J, Van Proeyen K, Raymackers JM, Deldicque L, Hespel P. Sprint interval training in hypoxia stimulates glycolytic enzyme activity. Med Sci Sports Exerc 2014; 45:2166-74. [PMID: 23604068 DOI: 10.1249/mss.0b013e31829734ae] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE In this study, we compared the effect of sprint interval training (SIT) in normoxia versus hypoxia on muscle glycolytic and oxidative capacity, monocarboxylate transporter content, and endurance exercise performance. METHODS Healthy male volunteers (18-30 yr) performed 6 wk of SIT on a cycling ergometer (30-s sprints vs 4.5-min rest intervals; 3 d · wk(-1)) in either normobaric hypoxia (HYP, FiO2 = 14.4%, n = 10) or normoxia (NOR, FiO2 = 20.9%, n = 9). The control group did not train (CON, n = 10). Training load was increased from four sprints per session in week 1 to nine sprints in week 6. Before and after SIT, subjects performed a maximal incremental exercise test plus a 10-min simulated time trial on a cycle ergometer in both normoxia (MAX nor and TT nor) and hypoxia (MAX hyp and TT hyp). A needle biopsy was taken from musculus vastus lateralis at rest 5-6 d after the last exercise session. RESULTS SIT increased muscle phosphofructokinase activity more in HYP (+59%, P < 0.05) than that in NOR (+17%), whereas citrate synthase activity was similar between groups. Compared with the pretest, power outputs corresponding to 4 mmol blood lactate in HYP during MAX nor (+7%) and MAX hyp (+9%) were slightly increased (P < 0.05), whereas values were constant in NOR. V·O 2max in MAX nor and TT performance in TT nor and TT hyp were increased by ≈ 6%-8% (P < 0.05) in either group. The training elevated monocarboxylate transporter 1 protein content by ≈ 70% (P < 0.05). In CON, all measurements were constant throughout the study. CONCLUSION SIT in hypoxia up-regulated muscle phosphofructokinase activity and the anaerobic threshold more than SIT in normoxia but did not enhance endurance exercise performance.
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Affiliation(s)
- Joke Puype
- 1Exercise Physiology Research Group, Department of Kinesiology, KU Leuven, Leuven, BELGIUM; and 2Institute of Neuroscience, Université catholique de Louvain, Brussels, BELGIUM
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Buchheit M, Laursen PB. High-intensity interval training, solutions to the programming puzzle. Part II: anaerobic energy, neuromuscular load and practical applications. Sports Med 2014; 43:927-54. [PMID: 23832851 DOI: 10.1007/s40279-013-0066-5] [Citation(s) in RCA: 362] [Impact Index Per Article: 36.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
High-intensity interval training (HIT) is a well-known, time-efficient training method for improving cardiorespiratory and metabolic function and, in turn, physical performance in athletes. HIT involves repeated short (<45 s) to long (2-4 min) bouts of rather high-intensity exercise interspersed with recovery periods (refer to the previously published first part of this review). While athletes have used 'classical' HIT formats for nearly a century (e.g. repetitions of 30 s of exercise interspersed with 30 s of rest, or 2-4-min interval repetitions ran at high but still submaximal intensities), there is today a surge of research interest focused on examining the effects of short sprints and all-out efforts, both in the field and in the laboratory. Prescription of HIT consists of the manipulation of at least nine variables (e.g. work interval intensity and duration, relief interval intensity and duration, exercise modality, number of repetitions, number of series, between-series recovery duration and intensity); any of which has a likely effect on the acute physiological response. Manipulating HIT appropriately is important, not only with respect to the expected middle- to long-term physiological and performance adaptations, but also to maximize daily and/or weekly training periodization. Cardiopulmonary responses are typically the first variables to consider when programming HIT (refer to Part I). However, anaerobic glycolytic energy contribution and neuromuscular load should also be considered to maximize the training outcome. Contrasting HIT formats that elicit similar (and maximal) cardiorespiratory responses have been associated with distinctly different anaerobic energy contributions. The high locomotor speed/power requirements of HIT (i.e. ≥95 % of the minimal velocity/power that elicits maximal oxygen uptake [v/p(·)VO(2max)] to 100 % of maximal sprinting speed or power) and the accumulation of high-training volumes at high-exercise intensity (runners can cover up to 6-8 km at v(·)VO(2max) per session) can cause significant strain on the neuromuscular/musculoskeletal system. For athletes training twice a day, and/or in team sport players training a number of metabolic and neuromuscular systems within a weekly microcycle, this added physiological strain should be considered in light of the other physical and technical/tactical sessions, so as to avoid overload and optimize adaptation (i.e. maximize a given training stimulus and minimize musculoskeletal pain and/or injury risk). In this part of the review, the different aspects of HIT programming are discussed, from work/relief interval manipulation to HIT periodization, using different examples of training cycles from different sports, with continued reference to the cardiorespiratory adaptations outlined in Part I, as well as to anaerobic glycolytic contribution and neuromuscular/musculoskeletal load.
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Affiliation(s)
- Martin Buchheit
- Physiology Unit, Football Performance and Science Department, ASPIRE, Academy for Sports Excellence, P.O. Box 22287, Doha, Qatar,
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Rossman MJ, Garten RS, Venturelli M, Amann M, Richardson RS. The role of active muscle mass in determining the magnitude of peripheral fatigue during dynamic exercise. Am J Physiol Regul Integr Comp Physiol 2014; 306:R934-40. [PMID: 24740653 DOI: 10.1152/ajpregu.00043.2014] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Greater peripheral quadriceps fatigue at the voluntary termination of single-leg knee-extensor exercise (KE), compared with whole-body cycling, has been attributed to confining group III and IV skeletal muscle afferent feedback to a small muscle mass, enabling the central nervous system (CNS) to tolerate greater peripheral fatigue. However, as task specificity and vastly differing systemic challenges may have complicated this interpretation, eight males were studied during constant workload trials to exhaustion at 85% of peak workload during single-leg and double-leg KE. It was hypothesized that because of the smaller muscle mass engaged during single-leg KE, a greater magnitude of peripheral quadriceps fatigue would be present at exhaustion. Vastus lateralis integrated electromyogram (iEMG) signal relative to the first minute of exercise, preexercise to postexercise maximal voluntary contractions (MVCs) of the quadriceps, and twitch-force evoked by supramaximal magnetic femoral nerve stimulation (Qtw,pot) quantified peripheral quadriceps fatigue. Trials performed with single-leg KE (8.1 ± 1.2 min; 45 ± 4 W) resulted in significantly greater peripheral quadriceps fatigue than double-leg KE (10 ± 1.3 min; 83 ± 7 W), as documented by changes in the iEMG signal (147 ± 24 vs. 85 ± 13%), MVC (-25 ± 3 vs. -12 ± 3%), and Qtw,pot (-44 ± 6 vs. -33 ± 7%), for single-leg and double-leg KE, respectively. Therefore, avoiding concerns over task specificity and cardiorespiratory limitations, this study reveals that a reduction in muscle mass permits the development of greater peripheral muscle fatigue and supports the concept that the CNS tolerates a greater magnitude of peripheral fatigue when the source of group III/IV afferent feedback is limited to a small muscle mass.
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Affiliation(s)
- Matthew J Rossman
- Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, Utah; Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah
| | - Ryan S Garten
- Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, Utah; Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah; and
| | - Massimo Venturelli
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah; and Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Markus Amann
- Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, Utah; Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah; Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah; and
| | - Russell S Richardson
- Geriatric Research, Education, and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, Utah; Department of Exercise and Sport Science, University of Utah, Salt Lake City, Utah; Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah; and
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Cardiovascular responses to counterweighted single-leg cycling: implications for rehabilitation. Eur J Appl Physiol 2014; 114:961-8. [PMID: 24492992 DOI: 10.1007/s00421-014-2830-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 01/20/2014] [Indexed: 12/11/2022]
Abstract
PURPOSE Although difficult to coordinate, single-leg cycling allows for greater muscle-specific exercise capacity and subsequently greater stimulus for metabolic and vascular adaptations compared to typical double-leg cycling. The purpose of this investigation was to compare metabolic, cardiovascular and perceptual responses of double-leg cycling to single-leg cycling with and without the use of a counterweight. METHODS Ten healthy individuals (age 22 ± 2 years; body mass 78.0 ± 11.2 kg; height 1.8 ± 0.1 m) performed three cycling conditions consisting of double-leg cycling (DL), non-counterweighted single-leg cycling (SLNCW) and single-leg cycling with a 97 N counterweight attached to the unoccupied crank arm (SLCW). For each condition, participants performed cycling trials (80 rpm) at three different work rates (40, 80 and 120 W). Oxygen consumption (VO2), respiratory exchange ratio (RER), heart rate (HR), femoral blood flow, rating of perceived exertion (RPE) and liking score were measured. RESULTS VO2 and HR were similar for DL and SLCW conditions. However, during SLNCW, VO2 was at least 23 ± 13 % greater and HR was at least 15 ± 11 % greater compared to SLCW across all three intensities. Femoral blood flow was at least 65.5 ± 43.8 % greater during SLCW compared to DL cycling across all three intensities. RPE was lower and liking scores were greater for SLCW compared to SLNCW condition. CONCLUSION Counterweighted single-leg cycling provides an exercise modality that is more tolerable than typical single-leg cycling while inducing greater peripheral stress for the same cardiovascular demand as double-leg cycling.
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Ribeiro F, Thériault ME, Debigaré R, Maltais F. Should all patients with COPD be exercise trained? J Appl Physiol (1985) 2013; 114:1300-8. [PMID: 23412902 DOI: 10.1152/japplphysiol.01124.2012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Exercise training is one of the most powerful interventions to provide symptomatic relief in patients with chronic obstructive pulmonary disease (COPD). The purpose of this minireview is to discuss how exercise training can improve limb muscle dysfunction in this disease. Various exercise training strategies will be outlined, along with their beneficial effects and potential limitations. Strategies to optimize the gains achievable with exercise training will be presented. Whether exercise training may exert deleterious effects in some patients will also be discussed.
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Affiliation(s)
- Fernanda Ribeiro
- Centre de Recherche, Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, Canada
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