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O'Bryan SJ, Hiam D, Lamon S. Single-session measures of quadriceps neuromuscular function are reliable in healthy females and unaffected by age. Eur J Appl Physiol 2024; 124:1719-1732. [PMID: 38189826 PMCID: PMC11130065 DOI: 10.1007/s00421-023-05395-x] [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: 08/13/2023] [Accepted: 12/07/2023] [Indexed: 01/09/2024]
Abstract
PURPOSE This study aimed to determine the inter-session reliability of quadriceps neuromuscular function measurements in healthy young and older females. METHODS Twenty-six females aged 19-74 years completed two identical experimental sessions on different days. Quadriceps neuromuscular function measurements included isometric maximal voluntary force, high- and low-frequency twitch force, voluntary and evoked (H-reflex, M-wave) electromyography (EMG), and estimated maximal torque, velocity and power derived from torque-velocity relationships. Intra-class correlation coefficients (ICCs), coefficients of variation (CoV) and Bland-Altman plots assessed inter-session reliability. The effect of age on reliability was assessed by linear regression. RESULTS Excellent reliability (ICC > 0.8) was shown for all voluntary and evoked mechanical outcomes. Vastus lateralis EMG outcomes showed excellent reliability (ICC > 0.8) with CoVs < 12%, which were better than those of vastus medialis and rectus femoris. Age was not associated with reliability for 27/28 outcomes (P > 0.05). CONCLUSION Excellent reliability of voluntary and evoked force and vastus lateralis EMG outcomes measured in healthy females can be attained in one experimental session, irrespective of age. Female neuromuscular function can be accurately assessed across the lifespan with minimal inconvenience, increasing feasibility for future research. The random error should however be considered when quantifying age-related differences in neuromuscular function.
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Affiliation(s)
- Steven J O'Bryan
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, 221 Burwood Highway, Burwood, Geelong, VIC, 3125, Australia.
- Institute for Health and Sport, Victoria University, Melbourne, Australia.
| | - Danielle Hiam
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, 221 Burwood Highway, Burwood, Geelong, VIC, 3125, Australia
| | - Séverine Lamon
- Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, 221 Burwood Highway, Burwood, Geelong, VIC, 3125, Australia
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Mendonca GV, Alves DL, Fitas A, Pezarat-Correia P. Minimum velocity threshold in response to the free-weight back squat: reliability and validity of different submaximal loading schemes. Eur J Appl Physiol 2024:10.1007/s00421-024-05494-3. [PMID: 38730035 DOI: 10.1007/s00421-024-05494-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 04/20/2024] [Indexed: 05/12/2024]
Abstract
PURPOSE To explore if mean concentric velocity (MCV) of the last repetition before set failure differs between free-weight back squat protocols with greater emphasis on metabolic accumulation vs. mechanical loading. The between-set and between-day reliability of terminal MCV obtained with these different loading schemes was also determined. METHODS Fifteen healthy male participants (18-30 years) were included. They all were required to exhibit a relative strength ≥ 1.5 times their body mass. MCVs were obtained at one-repetition maximum (1RM) and with two submaximal protocols (metabolic emphasis: three sets of 40%1RM with blood-flow restriction vs. mechanical emphasis: three sets 80%1RM without blood-flow restriction). Participants were instructed to reach maximal intended concentric velocity in each repetition up to failure. RESULTS Set failure was achieved at a faster MCV with the metabolic protocol (p < 0.05). The reliability of MCV at failure reached higher values for the metabolic loading scheme. However, while the MCV achieved at failure during the metabolic protocol was systematically higher than the MCV at 1RM (p < 0.05), this was not entirely the case for the mechanical protocol (similar to 1RM MCV during the last sets in both testing days). Finally, the absolute error derived from estimating the MCV at 1RM based on the MCV obtained at set failure with the mechanical protocol was considerably high (≥ 0.05 m/s). CONCLUSION This study indicates that MCV obtained at set failure is dependent on the specificity of the physiological demands of exercise. Thus, MCVs obtained at failure with submaximal loads should not be used to estimate 1RM MCV.
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Affiliation(s)
- Goncalo V Mendonca
- Neuromuscular Research Lab, Faculdade de Motricidade Humana, Universidade de Lisboa, Estrada da Costa, Cruz Quebrada, 1499-002, Dafundo, Portugal.
- CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa, Estrada da Costa, Cruz Quebrada, 1499-002, Dafundo, Portugal.
| | - Diogo L Alves
- Neuromuscular Research Lab, Faculdade de Motricidade Humana, Universidade de Lisboa, Estrada da Costa, Cruz Quebrada, 1499-002, Dafundo, Portugal
| | - Afonso Fitas
- Neuromuscular Research Lab, Faculdade de Motricidade Humana, Universidade de Lisboa, Estrada da Costa, Cruz Quebrada, 1499-002, Dafundo, Portugal
- CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa, Estrada da Costa, Cruz Quebrada, 1499-002, Dafundo, Portugal
| | - Pedro Pezarat-Correia
- Neuromuscular Research Lab, Faculdade de Motricidade Humana, Universidade de Lisboa, Estrada da Costa, Cruz Quebrada, 1499-002, Dafundo, Portugal
- CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa, Estrada da Costa, Cruz Quebrada, 1499-002, Dafundo, Portugal
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Nuzzo JL, Pinto MD, Kirk BJC, Nosaka K. Resistance Exercise Minimal Dose Strategies for Increasing Muscle Strength in the General Population: an Overview. Sports Med 2024; 54:1139-1162. [PMID: 38509414 PMCID: PMC11127831 DOI: 10.1007/s40279-024-02009-0] [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] [Accepted: 02/23/2024] [Indexed: 03/22/2024]
Abstract
Many individuals do not participate in resistance exercise, with perceived lack of time being a key barrier. Minimal dose strategies, which generally reduce weekly exercise volumes to less than recommended guidelines, might improve muscle strength with minimal time investment. However, minimal dose strategies and their effects on muscle strength are still unclear. Here our aims are to define and characterize minimal dose resistance exercise strategies and summarize their effects on muscle strength in individuals who are not currently engaged in resistance exercise. The minimal dose strategies overviewed were: "Weekend Warrior," single-set resistance exercise, resistance exercise "snacking," practicing the strength test, and eccentric minimal doses. "Weekend Warrior," which minimizes training frequency, is resistance exercise performed in one weekly session. Single-set resistance exercise, which minimizes set number and session duration, is one set of multiple exercises performed multiple times per week. "Snacks," which minimize exercise number and session duration, are brief bouts (few minutes) of resistance exercise performed once or more daily. Practicing the strength test, which minimizes repetition number and session duration, is one maximal repetition performed in one or more sets, multiple days per week. Eccentric minimal doses, which eliminate or minimize concentric phase muscle actions, are low weekly volumes of submaximal or maximal eccentric-only repetitions. All approaches increase muscle strength, and some approaches improve other outcomes of health and fitness. "Weekend Warrior" and single-set resistance exercise are the approaches most strongly supported by current research, while snacking and eccentric minimal doses are emerging concepts with promising results. Public health programs can promote small volumes of resistance exercise as being better for muscle strength than no resistance exercise at all.
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Affiliation(s)
- James L Nuzzo
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, 270 Joondalup Drive, Joondalup, WA, 6027, Australia.
| | - Matheus D Pinto
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, 270 Joondalup Drive, Joondalup, WA, 6027, Australia
| | - Benjamin J C Kirk
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, 270 Joondalup Drive, Joondalup, WA, 6027, Australia
| | - Kazunori Nosaka
- Centre for Human Performance, School of Medical and Health Sciences, Edith Cowan University, 270 Joondalup Drive, Joondalup, WA, 6027, Australia
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Chander DS, Tomezzoli A, Cavatorta MP, Gréau M, Marie S, Pontonnier C. Biomechanical requirements of meat cutting tasks: A pilot study quantifying tasks sustainability and assistance required at the wrist. APPLIED ERGONOMICS 2024; 116:104186. [PMID: 38052153 DOI: 10.1016/j.apergo.2023.104186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 11/14/2023] [Accepted: 11/27/2023] [Indexed: 12/07/2023]
Abstract
The meat processing industry is particularly affected by distal upper limb musculoskeletal disorders. This pilot study aims at proposing a methodology able to quantify biomechanical requirements of meat cutting tasks at butchers' dominant wrist and, when necessary, at estimating the assistance needed to reach sustainability. Six professional butchers repeatedly cut pieces of pork. Joint angles were recorded using a motion capture system, cutting forces using an instrumented knife. Sustainability was computed by the maximal acceptable effort method. Assistance requirements were computed for isolated stressful exertions and for overall work cycle sustainability. Five butchers exceeded the sustainability threshold for wrist flexion. Ulnar or radial deviation torques were excessive for 2 and 3 of them, respectively. Extension torques were sustainable. The peak assistive torque for isolated exertions was at most 1.1Nm, 1.6Nm and 1.1Nm, and the percentage of assistance for overall sustainability was at most 60%, 56% and 56% for wrist flexion, ulnar and radial deviation, respectively.
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Sašek M, Šarabon N, Smajla D. Exploring the relationship between lower limb strength, strength asymmetries, and curvilinear sprint performance: Findings from a pilot study. Sci Prog 2024; 107:368504241247998. [PMID: 38651328 PMCID: PMC11036933 DOI: 10.1177/00368504241247998] [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] [Indexed: 04/25/2024]
Abstract
Team sports involve various sprinting actions, including curvilinear sprints, yet their neuromuscular factors have been understudied. The aim of this cross-sectional study was to investigate the relationship between lower limb muscle strength, strength asymmetries, linear sprint and curvilinear sprint performance. At two visits 12 male (age: 24.8 ± 4.7 years, height: 1.82 ± 0.06 m, body mass: 80 ± 6.58 kg) and 6 female (age: 20.8 ± 1.33 years, body height: 1.60 ± 0.02 m, body mass: 55.3 ± 2.88 kg) student-athletes completed isometric strength measurements of the knee flexors (KF), knee extensors (KE), hip abductors (HABD), hip adductors (HADD), as well as linear sprint and curvilinear sprint to the right and left. Sprint split times over 30 m (t30) were measured and curvilinear sprint split time deficits (t30deficit) and inter-limb strength asymmetries were calculated. Very large negative correlations were observed between HADD and HABD strength on one side and t30 of curvilinear sprint to the left (r = -0.75 and -0.71; p < 0.001) and right (ρ = -0.81 and -0.70; p < 0.001) on the other. The regression model consisting of HADD, HABD, and KF explained 76% and 67% of the variance in left and right curvilinear sprint t30, respectively. Similarly, 59% of the left curvilinear sprint t30deficit variance was explained by the HABD and KF strength. High inter-limb HABD strength symmetry was related to better left and right curvilinear sprint t30 (r = 0.71 and ρ = 0.75, p < 0.001). These results highlight the pivotal role of hip strength for curvilinear sprint speed, and emphasize the need of symmetrical HABD muscle strength to optimize neuromuscular function during curvilinear sprint.
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Affiliation(s)
- Matic Sašek
- Faculty of Health Sciences, University of Primorska, Izola, Slovenia
| | - Nejc Šarabon
- Faculty of Health Sciences, University of Primorska, Izola, Slovenia
- Andrej Marušič Institute, University of Primorska, Koper, Slovenia
- Laboratory for Motor Control and Motor Behavior, S2P, Science To Practice, Ltd, Ljubljana, Slovenia
- Ludwig Boltzmann Institute for Rehabilitation Research, Vienna, Austria
| | - Darjan Smajla
- Faculty of Health Sciences, University of Primorska, Izola, Slovenia
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Althobaiti S, Falla D. Reliability and criterion validity of handheld dynamometry for measuring trunk muscle strength in people with and without chronic non-specific low back pain. Musculoskelet Sci Pract 2023; 66:102799. [PMID: 37343403 DOI: 10.1016/j.msksp.2023.102799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 05/04/2023] [Accepted: 06/09/2023] [Indexed: 06/23/2023]
Abstract
BACKGROUND Evaluating trunk strength is an important aspect of the physical examination of people with low back pain (LBP). Thus, reliable, valid, and easily applied measurement tools are needed to quantify trunk muscle strength and monitor changes in response to interventions. OBJECTIVES To determine within-day and between-day test re-test reliability and criterion validity of a handheld dynamometer (HHD) to evaluate maximum isometric trunk strength in people with chronic LBP and asymptomatic individuals. DESIGN Reliability and criterion validity study. METHODS Twenty adult participants with chronic, non-specific LBP and 35 asymptomatic individuals participated. Isometric trunk flexion, extension, and rotation strength were evaluated with the HHD (Active force 2) and the within-day and between-day reliability were determined with intraclass correlation coefficients (ICC2,1) and the standard error of the measurements (SEM), minimal detectable change (MDC), and the limits of agreement (LOA) using Bland-Altman plots. Criterion validity was evaluated using Pearson correlation coefficients to compare HHD measurements to isokinetic dynamometry for both isometric trunk flexion and extension strength. RESULTS Good to excellent within-day and between-day reliability was observed for people with LBP and asymptomatic individuals with (ICC2,1) of 0.73-0.93 and 0.62-0.92 respectively. A moderate to strong correlation was found between measurements with the HHD and the isokinetic dynamometer with a correlation of r = 0.68-0.78 and r = 0.56-0.59 for people with LBP and asymptomatic participants respectively. CONCLUSION A HHD is a reliable, valid, and clinically applicable tool for the measurement of trunk strength in adults with and without chronic LBP.
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Affiliation(s)
- Shouq Althobaiti
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, UK; Physical Therapy Department, College of Applied Medical Science, Taif University, Taif, Saudi Arabia.
| | - Deborah Falla
- Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, UK
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Rosa A, Coleman M, Haun C, Grgic J, Schoenfeld BJ. Repetition Performance, Rating of Perceived Discomfort, and Blood Lactate Responses to Different Rest Interval Lengths in Single-Joint and Multijoint Lower-Body Exercise. J Strength Cond Res 2023; 37:1350-1357. [PMID: 37347940 DOI: 10.1519/jsc.0000000000004508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/24/2023]
Abstract
ABSTRACT Rosa, A, Coleman, M, Haun, C, Grgic, J, and Schoenfeld, BJ. Repetition performance, rating of perceived discomfort, and blood lactate responses to different rest interval lengths in single-joint and multijoint lower-body exercise. J Strength Cond Res 37(7): 1350-1357, 2023-The purpose of this study was to examine the effects of different rest interval lengths (RILs) on repetition performance, rating of discomfort, and blood lactate responses during lower-body single-joint and multijoint exercises. This study used a counterbalanced design where each subject performed the Smith machine back squat (BS) and leg extension (LE) using 3 different RIL configurations (1, 2, and 3 minutes) in a randomized fashion. Data collection occurred over the span of 3 separate days. Volunteers were randomly allocated to perform the independent variables (RILs and exercises) in 1 of 12 potential configurations. The initial session was allotted for familiarization with the rating of discomfort scale and 10 repetition maximum testing. The other 2 sessions involved training with the different configurations of RIL length using both the BS and LE. Randomization ensured that the BS was performed first in one of the training sessions and the LE was performed first in the other session. Results indicated that longer RILs had a small positive effect on repetition performance, with longer rest durations allowing for more repetitions compared with shorter durations. The largest difference in repetition performance between RILs was observed between 1 minute and 2-3 minutes rest; there were trivial differences in repetition performance between 2 and 3 minutes rest for both the BS and LE. Blood lactate levels were slightly higher with longer RILs. Overall, BS showed greater increases in blood lactate compared with LE, and these differences were magnified over time. Exercise selection and RIL both influenced rating of discomfort, with LE producing less discomfort than BS and longer RILs reducing perceived discomfort. Our findings suggest that RIL influences the repetition performance, blood lactate, and rating of discomfort responses between single-joint and multijoint exercises.
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Affiliation(s)
- Avery Rosa
- Department of Exercise Science and Recreation, CUNY Lehman College, Bronx, New York
| | - Max Coleman
- Department of Exercise Science and Recreation, CUNY Lehman College, Bronx, New York
| | - Cody Haun
- Fitomics LLC, Alabaster, Alabama; and
| | - Jozo Grgic
- Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia
| | - Brad J Schoenfeld
- Department of Exercise Science and Recreation, CUNY Lehman College, Bronx, New York
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Hucteau E, Mallard J, Pivot X, Schott R, Pflumio C, Trensz P, Favret F, Pagano AF, Hureau TJ. Exacerbated central fatigue and reduced exercise capacity in early-stage breast cancer patients treated with chemotherapy. Eur J Appl Physiol 2023:10.1007/s00421-023-05177-5. [PMID: 36939876 DOI: 10.1007/s00421-023-05177-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 03/07/2023] [Indexed: 03/21/2023]
Abstract
PURPOSE The present study aimed to characterize the etiology of exercise-induced neuromuscular fatigue and its consequences on the force-duration relationship to provide mechanistic insights into the reduced exercise capacity characterizing early-stage breast cancer patients. METHODS Fifteen early-stage breast cancer patients and fifteen healthy women performed 60 maximal voluntary isometric quadriceps contractions (MVCs, 3 s of contraction, 2 s of relaxation). The critical force was determined as the mean force of the last six contractions, while W' was calculated as the force impulse generated above the critical force. Quadriceps muscle activation during exercise was estimated from vastus lateralis, vastus medialis and rectus femoris EMG. Central and peripheral fatigue were quantified via changes in pre- to postexercise quadriceps voluntary activation (ΔVA) and quadriceps twitch force (ΔQTw) evoked by supramaximal electrical stimulation, respectively. RESULTS Early-stage breast cancer patients demonstrated lower MVC than controls preexercise (- 15%, P = 0.022), and this reduction persisted throughout the 60-MVC exercise (- 21%, P = 0.002). The absolute critical force was lower in patients than in controls (144 ± 29N vs. 201 ± 47N, respectively, P < 0.001), while W' was similar (P = 0.546), resulting in lower total work done (- 23%, P = 0.001). This was associated with lower muscle activation in the vastus lateralis (P < 0.001), vastus medialis (P = 0.003) and rectus femoris (P = 0.003) in patients. Immediately following exercise, ΔVA showed a greater reduction in patients compared to controls (- 21.6 ± 13.3% vs. - 12.6 ± 7.7%, P = 0.040), while ΔQTw was similar (- 60.2 ± 13.2% vs. - 52.8 ± 19.4%, P = 0.196). CONCLUSION These findings support central fatigue as a primary cause of the reduction in exercise capacity characterizing early-stage breast cancer patients treated with chemotherapy. CLINICAL TRIALS REGISTRATION No. NCT04639609-November 20, 2020.
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Affiliation(s)
- Elyse Hucteau
- Biomedicine Research Centre of Strasbourg (CRBS), Mitochondria, Oxidative Stress, and Muscular Protection Laboratory (UR 3072), Strasbourg, France
- Faculty of Sport Sciences, European Centre for Education, Research and Innovation in Exercise Physiology (CEERIPE), University of Strasbourg, 4 rue Blaise Pascal, CS 90032, 67081, Strasbourg Cedex, France
- Institute of Cancerology Strasbourg Europe (ICANS), Strasbourg, France
| | - Joris Mallard
- Biomedicine Research Centre of Strasbourg (CRBS), Mitochondria, Oxidative Stress, and Muscular Protection Laboratory (UR 3072), Strasbourg, France
- Faculty of Sport Sciences, European Centre for Education, Research and Innovation in Exercise Physiology (CEERIPE), University of Strasbourg, 4 rue Blaise Pascal, CS 90032, 67081, Strasbourg Cedex, France
- Institute of Cancerology Strasbourg Europe (ICANS), Strasbourg, France
| | - Xavier Pivot
- Institute of Cancerology Strasbourg Europe (ICANS), Strasbourg, France
| | - Roland Schott
- Institute of Cancerology Strasbourg Europe (ICANS), Strasbourg, France
| | - Carole Pflumio
- Institute of Cancerology Strasbourg Europe (ICANS), Strasbourg, France
| | - Philippe Trensz
- Institute of Cancerology Strasbourg Europe (ICANS), Strasbourg, France
| | - Fabrice Favret
- Biomedicine Research Centre of Strasbourg (CRBS), Mitochondria, Oxidative Stress, and Muscular Protection Laboratory (UR 3072), Strasbourg, France
- Faculty of Sport Sciences, European Centre for Education, Research and Innovation in Exercise Physiology (CEERIPE), University of Strasbourg, 4 rue Blaise Pascal, CS 90032, 67081, Strasbourg Cedex, France
| | - Allan F Pagano
- Biomedicine Research Centre of Strasbourg (CRBS), Mitochondria, Oxidative Stress, and Muscular Protection Laboratory (UR 3072), Strasbourg, France
- Faculty of Sport Sciences, European Centre for Education, Research and Innovation in Exercise Physiology (CEERIPE), University of Strasbourg, 4 rue Blaise Pascal, CS 90032, 67081, Strasbourg Cedex, France
| | - Thomas J Hureau
- Biomedicine Research Centre of Strasbourg (CRBS), Mitochondria, Oxidative Stress, and Muscular Protection Laboratory (UR 3072), Strasbourg, France.
- Faculty of Sport Sciences, European Centre for Education, Research and Innovation in Exercise Physiology (CEERIPE), University of Strasbourg, 4 rue Blaise Pascal, CS 90032, 67081, Strasbourg Cedex, France.
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Nuzzo JL. Narrative Review of Sex Differences in Muscle Strength, Endurance, Activation, Size, Fiber Type, and Strength Training Participation Rates, Preferences, Motivations, Injuries, and Neuromuscular Adaptations. J Strength Cond Res 2023; 37:494-536. [PMID: 36696264 DOI: 10.1519/jsc.0000000000004329] [Citation(s) in RCA: 39] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
ABSTRACT Nuzzo, JL. Narrative review of sex differences in muscle strength, endurance, activation, size, fiber type, and strength training participation rates, preferences, motivations, injuries, and neuromuscular adaptations. J Strength Cond Res 37(2): 494-536, 2023-Biological sex and its relation with exercise participation and sports performance continue to be discussed. Here, the purpose was to inform such discussions by summarizing the literature on sex differences in numerous strength training-related variables and outcomes-muscle strength and endurance, muscle mass and size, muscle fiber type, muscle twitch forces, and voluntary activation; strength training participation rates, motivations, preferences, and practices; and injuries and changes in muscle size and strength with strength training. Male subjects become notably stronger than female subjects around age 15 years. In adults, sex differences in strength are more pronounced in upper-body than lower-body muscles and in concentric than eccentric contractions. Greater male than female strength is not because of higher voluntary activation but to greater muscle mass and type II fiber areas. Men participate in strength training more frequently than women. Men are motivated more by challenge, competition, social recognition, and a desire to increase muscle size and strength. Men also have greater preference for competitive, high-intensity, and upper-body exercise. Women are motivated more by improved attractiveness, muscle "toning," and body mass management. Women have greater preference for supervised and lower-body exercise. Intrasexual competition, mate selection, and the drive for muscularity are likely fundamental causes of exercise behaviors in men and women. Men and women increase muscle size and strength after weeks of strength training, but women experience greater relative strength improvements depending on age and muscle group. Men exhibit higher strength training injury rates. No sex difference exists in strength loss and muscle soreness after muscle-damaging exercise.
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Affiliation(s)
- James L Nuzzo
- School of Medical and Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia
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Millet GY, Bertrand MF, Lapole T, Féasson L, Rozand V, Hupin D. Measuring objective fatigability and autonomic dysfunction in clinical populations: How and why? Front Sports Act Living 2023; 5:1140833. [PMID: 37065809 PMCID: PMC10101442 DOI: 10.3389/fspor.2023.1140833] [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: 01/09/2023] [Accepted: 03/13/2023] [Indexed: 04/18/2023] Open
Abstract
Fatigue is a major symptom in many diseases, often among the most common and severe ones and may last for an extremely long period. Chronic fatigue impacts quality of life, reduces the capacity to perform activities of daily living, and has socioeconomical consequences such as impairing return to work. Despite the high prevalence and deleterious consequences of fatigue, little is known about its etiology. Numerous causes have been proposed to explain chronic fatigue. They encompass psychosocial and behavioral aspects (e.g., sleep disorders) and biological (e.g., inflammation), hematological (e.g., anemia) as well as physiological origins. Among the potential causes of chronic fatigue is the role of altered acute fatigue resistance, i.e. an increased fatigability for a given exercise, that is related to physical deconditioning. For instance, we and others have recently evidenced that relationships between chronic fatigue and increased objective fatigability, defined as an abnormal deterioration of functional capacity (maximal force or power), provided objective fatigability is appropriately measured. Indeed, in most studies in the field of chronic diseases, objective fatigability is measured during single-joint, isometric exercises. While those studies are valuable from a fundamental science point of view, they do not allow to test the patients in ecological situations when the purpose is to search for a link with chronic fatigue. As a complementary measure to the evaluation of neuromuscular function (i.e., fatigability), studying the dysfunction of the autonomic nervous system (ANS) is also of great interest in the context of fatigue. The challenge of evaluating objective fatigability and ANS dysfunction appropriately (i.e.,. how?) will be discussed in the first part of the present article. New tools recently developed to measure objective fatigability and muscle function will be presented. In the second part of the paper, we will discuss the interest of measuring objective fatigability and ANS (i.e. why?). Despite the beneficial effects of physical activity in attenuating chronic fatigue have been demonstrated, a better evaluation of fatigue etiology will allow to personalize the training intervention. We believe this is key in order to account for the complex, multifactorial nature of chronic fatigue.
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Affiliation(s)
- Guillaume Y. Millet
- Université Jean Monnet Saint-Etienne, Université Savoie Mont-Blanc, Inter-university Laboratory of Human Movement Biology, F-42023, Saint-Etienne, Lyon, France
- Institut Universitaire de France (IUF), Paris, France
- Correspondence: Guillaume Y. Millet
| | - Mathilde F. Bertrand
- Université Jean Monnet Saint-Etienne, Université Savoie Mont-Blanc, Inter-university Laboratory of Human Movement Biology, F-42023, Saint-Etienne, Lyon, France
| | - Thomas Lapole
- Université Jean Monnet Saint-Etienne, Université Savoie Mont-Blanc, Inter-university Laboratory of Human Movement Biology, F-42023, Saint-Etienne, Lyon, France
| | - Léonard Féasson
- Université Jean Monnet Saint-Etienne, Université Savoie Mont-Blanc, Inter-university Laboratory of Human Movement Biology, F-42023, Saint-Etienne, Lyon, France
- Service de physiologie clinique et de l'exercice, CHU de Saint-Étienne, Saint-Étienne, France
- Centre Référent Maladies Neuromusculaires rares - Euro-NmD, CHU de Saint-Étienne, Saint-Étienne, France
| | - Vianney Rozand
- Université Jean Monnet Saint-Etienne, Université Savoie Mont-Blanc, Inter-university Laboratory of Human Movement Biology, F-42023, Saint-Etienne, Lyon, France
| | - David Hupin
- Service de physiologie clinique et de l'exercice, CHU de Saint-Étienne, Saint-Étienne, France
- Jean Monnet University Saint-Etienne, Mines Saint-Etienne, University hospital of Saint-Etienne, INSERM, SAINBIOSE, U1059, DVH team, Saint-Etienne, France
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Diong J, Kishimoto KC, Butler JE, Héroux ME. Muscle electromyographic activity normalized to maximal muscle activity, not to Mmax, better represents voluntary activation. PLoS One 2022; 17:e0277947. [PMID: 36409688 PMCID: PMC9678282 DOI: 10.1371/journal.pone.0277947] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 11/07/2022] [Indexed: 11/22/2022] Open
Abstract
In human applied physiology studies, the amplitude of recorded muscle electromyographic activity (EMG) is often normalized to maximal EMG recorded during a maximal voluntary contraction. When maximal contractions cannot be reliably obtained (e.g. in people with muscle paralysis, anterior cruciate ligament injury, or arthritis), EMG is sometimes normalized to the maximal compound muscle action potiential evoked by stimulation, the Mmax. However, it is not known how these two methods of normalization affect the conclusions and comparability of studies. To address this limitation, we investigated the relationship between voluntary muscle activation and EMG normalized either to maximal EMG or to Mmax. Twenty-five able-bodied adults performed voluntary isometric ankle plantarflexion contractions to a range of percentages of maximal voluntary torque. Ankle torque, plantarflexor muscle EMG, and voluntary muscle activation measured by twitch interpolation were recorded. EMG recorded at each contraction intensity was normalized to maximal EMG or to Mmax for each plantarflexor muscle, and the relationship between the two normalization approaches quantified. A slope >1 indicated EMG amplitude normalized to maximal EMG (vertical axis) was greater than EMG normalized to Mmax (horizontal axis). Mean estimates of the slopes were large and had moderate precision: soleus 8.7 (95% CI 6.9 to 11.0), medial gastrocnemius 13.4 (10.5 to 17.0), lateral gastrocnemius 11.4 (9.4 to 14.0). This indicates EMG normalized to Mmax is approximately eleven times smaller than EMG normalized to maximal EMG. Normalization to maximal EMG gave closer approximations to the level of voluntary muscle activation assessed by twitch interpolation.
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Affiliation(s)
- Joanna Diong
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, New South Wales, Australia
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia
- * E-mail:
| | - Kenzo C. Kishimoto
- School of Health Sciences, Faculty of Medicine and Health, The University of Sydney, Camperdown, New South Wales, Australia
| | - Jane E. Butler
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, Kensington, New South Wales, Australia
| | - Martin E. Héroux
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, Kensington, New South Wales, Australia
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12
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Shouting strengthens voluntary force during sustained maximal effort through enhancement of motor system state via motor commands. Sci Rep 2022; 12:16182. [PMID: 36171262 PMCID: PMC9519961 DOI: 10.1038/s41598-022-20643-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 09/16/2022] [Indexed: 11/08/2022] Open
Abstract
Previous research indicates that shouting during momentary maximal exertion effort potentiates the maximal voluntary force through the potentiation of motor cortical excitability. However, the muscular force-enhancing effects of shouting on sustained maximal force production remain unclear. We investigated the effect of shouting on the motor system state by examining motor evoked potentials in response to transcranial magnetic stimulation applied over the hand area of the contralateral primary motor cortex (M1) during sustained maximal voluntary contraction, and by assessing handgrip maximal voluntary force. We observed that shouting significantly increased handgrip maximal voluntary force and reduced the silent period. Our results indicate that shouting increased handgrip voluntary force during sustained maximal exertion effort through the reduced silent period. This is the first objective evidence that the muscular force of shouting during maximal force exertion is associated with the potentiation of motor system activity produced by the additional drive of shouting operating on the motor system (i.e., shouting-induced excitatory input to M1).
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13
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Tan R, Pennell A, Price KM, Karl ST, Seekamp-Hicks NG, Paniagua KK, Weiderman GD, Powell JP, Sharabidze LK, Lincoln IG, Kim JM, Espinoza MF, Hammer MA, Goulding RP, Bailey SJ. Effects of Dietary Nitrate Supplementation on Performance and Muscle Oxygenation during Resistance Exercise in Men. Nutrients 2022; 14:nu14183703. [PMID: 36145080 PMCID: PMC9504620 DOI: 10.3390/nu14183703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 08/31/2022] [Accepted: 09/05/2022] [Indexed: 11/16/2022] Open
Abstract
The purpose of the current study was to assess the effects of acute and short-term nitrate (NO3−)-rich beetroot juice (BR) supplementation on performance outcomes and muscle oxygenation during bench press and back squat exercise. Fourteen recreationally active males were assigned in a randomized, double-blind, crossover design to supplement for 4 days in two conditions: (1) NO3−-depleted beetroot juice (PL; 0.10 mmol NO3− per day) and (2) BR (11.8 mmol NO3− per day). On days 1 and 4 of the supplementation periods, participants completed 2 sets of 2 × 70%1RM interspersed by 2 min of recovery, followed by one set of repetitions-to-failure (RTF) at 60%1RM for the determination of muscular power, velocity, and endurance. Quadriceps and pectoralis major tissue saturation index (TSI) were measured throughout exercise. Plasma [NO3−] and nitrite ([NO2−]) were higher after 1 and 4 days of supplementation with BR compared to PL (p < 0.05). Quadriceps and pectoralis major TSI were not different between conditions (p > 0.05). The number of RTF in bench press was 5% greater after acute BR ingestion compared to PL (PL: 23 ± 4 vs. BR: 24 ± 5, p < 0.05). There were no differences between BR and PL for RTF for back squat or power and velocity for back squat or bench press (p > 0.05). These data improve understanding on the ergogenic potential of BR supplementation during resistance exercise.
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Affiliation(s)
- Rachel Tan
- Department of Sports Medicine, Pepperdine University, Malibu, CA 90263, USA
- Correspondence: ; Tel.: +1-3105067041
| | - Adam Pennell
- Department of Sports Medicine, Pepperdine University, Malibu, CA 90263, USA
| | - Katherine M. Price
- Department of Sports Medicine, Pepperdine University, Malibu, CA 90263, USA
| | - Sean T. Karl
- Department of Sports Medicine, Pepperdine University, Malibu, CA 90263, USA
| | | | | | - Grant D. Weiderman
- Department of Sports Medicine, Pepperdine University, Malibu, CA 90263, USA
| | - Joanna P. Powell
- Department of Sports Medicine, Pepperdine University, Malibu, CA 90263, USA
| | - Luka K. Sharabidze
- Department of Sports Medicine, Pepperdine University, Malibu, CA 90263, USA
| | | | - Justin M. Kim
- Department of Sports Medicine, Pepperdine University, Malibu, CA 90263, USA
| | | | - Maya A. Hammer
- Department of Sports Medicine, Pepperdine University, Malibu, CA 90263, USA
| | - Richie P. Goulding
- Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, 1081 HZ Amsterdam, The Netherlands
| | - Stephen J. Bailey
- School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough LE11 3TU, UK
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14
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Tomezzoli A, Fréchède B, Duprey S. Slouched and erect sitting postures affect upper limb maximum voluntary force levels and fatiguability: a randomized experimental study. IISE Trans Occup Ergon Hum Factors 2022; 10:142-150. [PMID: 35930291 DOI: 10.1080/24725838.2022.2110544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Occupational ApplicationsModifying the spinal curvature is an empirical approach to treating upper limb musculoskeletal disorders, often attributed to the balance between physical stress and individual functional capacities. We completed an experimental biomechanical study to quantify the effect of seated spinal posture on upper limb functional capacities. Isometric maximum muscle voluntary forces (MVFs) were measured at participants' shoulder, elbow, and wrist. Fatiguability was also assessed during a repetitive painting task. Participants were asked to assume both slouched and erect spinal postures, in a random order. In the erect posture, participants achieved higher shoulder and elbow isometric MVF levels and took longer to reach a fatigue threshold. Thus, spinal posture tends to remotely influence upper limb functional capacities, especially at the shoulder and elbow. Ergonomists should consider spinal posture even when focusing on musculoskeletal disorders of the upper limb.Technical AbstractBackground: Musculoskeletal disorders are a major public health issue, and current treatments often remain unsatisfactory. Treatments based on spinal curvature modifications are empirically used for upper limb musculoskeletal disorders. PURPOSE To determine whether a slouched or erect sitting posture has an effect on upper limb functional capacities, with tests and outcomes focused on the risk of upper limb musculoskeletal disorders. METHODS Randomized experimental study, crossover design. Twenty-two right-handed healthy participants from the local area were assessed in a research laboratory. Participants' spinal curvatures were increased or decreased, through verbal instructions and light touch, to place them in a slouched or an erect posture that was stable and easily maintained, in a random order. Isometric maximum muscle voluntary forces (MVFs) were measured. Participants also performed a repetitive task that simulated painting, with fatigue level assessed using the CR10 Borg scale. Upper limb positioning, task setting, and instructions to participants were standardized., and the investigator was blind to the results of MVF measurements. The main outcomes were normalized differences in MVF values and time-to-reach "7" on the CR10 scale. RESULTS There were significantly higher MVF values in the erect posture for the shoulder and elbow, with respective mean (SD) normalized differences of 11.4 (18.2) and 11.8 (19.2)%; differences approached significance at the wrist [7.7 (18.5)%]. The normalized difference in time-to-reach "7" on the CR10 scale was significantly higher in the erect posture (by 11.4%). CONCLUSIONS Spinal posture modified individual upper limb functional capacities and could thus influence the risk of upper limb musculoskeletal disorders.
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Affiliation(s)
- Aurélie Tomezzoli
- Laboratoire de Biomécanique et Mécanique des Chocs, Univ Lyon, Univ Gustave Eiffel, Univ Claude Bernard Lyon 1, LBMC UMR T_ 9406, F-69622 Lyon, France
| | - Bertrand Fréchède
- Laboratoire de Biomécanique et Mécanique des Chocs, Univ Lyon, Univ Gustave Eiffel, Univ Claude Bernard Lyon 1, LBMC UMR T_ 9406, F-69622 Lyon, France
| | - Sonia Duprey
- Laboratoire de Biomécanique et Mécanique des Chocs, Univ Lyon, Univ Gustave Eiffel, Univ Claude Bernard Lyon 1, LBMC UMR T_ 9406, F-69622 Lyon, France
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15
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Boccia G, D’Emanuele S, Brustio PR, Beratto L, Tarperi C, Casale R, Sciarra T, Rainoldi A. Strength Asymmetries Are Muscle-Specific and Metric-Dependent. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19148495. [PMID: 35886350 PMCID: PMC9319678 DOI: 10.3390/ijerph19148495] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/06/2022] [Accepted: 07/08/2022] [Indexed: 12/10/2022]
Abstract
We investigated if dominance affected upper limbs muscle function, and we calculated the level of agreement in asymmetry direction across various muscle-function metrics of two heterologous muscle groups. We recorded elbow flexors and extensors isometric strength of the dominant and non-dominant limb of 55 healthy adults. Participants performed a series of explosive contractions of maximal and submaximal amplitudes to record three metrics of muscle performance: maximal voluntary force (MVF), rate of force development (RFDpeak), and RFD-Scaling Factor (RFD-SF). At the population level, the MVF was the only muscle function that showed a difference between the dominant and non-dominant sides, being on average slightly (3–6%) higher on the non-dominant side. At the individual level, the direction agreement among heterologous muscles was poor for all metrics (Kappa values ≤ 0.15). When considering the homologous muscles, the direction agreement was moderate between MVF and RFDpeak (Kappa = 0.37) and low between MVF and RFD-SF (Kappa = 0.01). The asymmetries are muscle-specific and rarely favour the same side across different muscle-performance metrics. At the individual level, no one side is more performative than the other: each limb is favoured depending on muscle group and performance metric. The present findings can be used by practitioners that want to decrease the asymmetry levels as they should prescribe specific exercise training for each muscle.
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Affiliation(s)
- Gennaro Boccia
- Department of Clinical and Biological Sciences, University of Turin, 10126 Turin, Italy; (G.B.); (P.R.B.); (C.T.)
- NeuroMuscularFunction Research Group, School of Exercise and Sport Science, SUISM, University of Turin, 10126 Turin, Italy;
| | - Samuel D’Emanuele
- Department of Neuroscience, Biomedicine and Movement, University of Verona, 37129 Verona, Italy;
| | - Paolo Riccardo Brustio
- Department of Clinical and Biological Sciences, University of Turin, 10126 Turin, Italy; (G.B.); (P.R.B.); (C.T.)
- NeuroMuscularFunction Research Group, School of Exercise and Sport Science, SUISM, University of Turin, 10126 Turin, Italy;
- Department of Neuroscience, Biomedicine and Movement, University of Verona, 37129 Verona, Italy;
| | - Luca Beratto
- NeuroMuscularFunction Research Group, School of Exercise and Sport Science, SUISM, University of Turin, 10126 Turin, Italy;
| | - Cantor Tarperi
- Department of Clinical and Biological Sciences, University of Turin, 10126 Turin, Italy; (G.B.); (P.R.B.); (C.T.)
- Department of Neuroscience, Biomedicine and Movement, University of Verona, 37129 Verona, Italy;
| | - Roberto Casale
- Opusmedica Persons Care & Research, NPO, 29121 Piacenza, Italy;
| | - Tommaso Sciarra
- Joint Veterans Defence Center, Scientific Department, Army Medical Center, 00184 Rome, Italy;
| | - Alberto Rainoldi
- NeuroMuscularFunction Research Group, School of Exercise and Sport Science, SUISM, University of Turin, 10126 Turin, Italy;
- Department of Medical Sciences, University of Turin, 10126 Turin, Italy
- Correspondence:
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16
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Vernillo G, Barbi C, Temesi J, Giuriato G, Giuseppe Laginestra F, Martignon C, Schena F, Venturelli M. Reliability of relaxation properties of knee-extensor muscles induced by transcranial magnetic stimulation. Neurosci Lett 2022; 782:136694. [DOI: 10.1016/j.neulet.2022.136694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 05/18/2022] [Accepted: 05/19/2022] [Indexed: 10/18/2022]
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17
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Augsburger GR, Soloveva A, Carr JC. Sex and limb comparisons of neuromuscular function in the morning versus the evening. Physiol Rep 2022; 10:e15260. [PMID: 35581749 PMCID: PMC9114651 DOI: 10.14814/phy2.15260] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 03/20/2022] [Accepted: 03/23/2022] [Indexed: 06/04/2023] Open
Abstract
The time-of-day influence on neuromuscular function is well-documented, but important details remain elusive. It is currently unknown whether males and females differ in their diurnal variation for optimal neuromuscular performance. The purpose of this study is to identify the time-of-day influence on neuromuscular function between sexes and determine whether these responses differ for the upper versus lower limbs. A group of males (n = 12) and females (n = 15) completed neuromuscular performance testing in the morning (07:00-09:00) and evening (17:00-19:00) on separate days in a randomized order. Maximal force, the normalized rate of force development, EMG, normalized EMG rise, and submaximal force steadiness were compared between morning and evening hours. The main findings show that maximal force was greater in the evening for the knee extensors (d = 0.570, p < 0.01) but not the elbow flexors (d = 0.212, p = 0.281), whereas maximal muscle excitation was greater in the evening for the biceps brachii (d = 0.348, p < 0.01) but not the vastus lateralis (d = 0.075, p = 0.526) with no influence of sex. However, force steadiness during knee extension was superior in the evening versus the morning for males (d = 0.734, p = 0.025) and compared to evening values for females (g = 1.19, p = 0.032). Overall, these findings show that time-of-day affects the knee extensors more than the elbow flexors and that diurnal variability between sexes appears to be task-dependent.
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Affiliation(s)
| | - Alisa Soloveva
- Kinesiology DepartmentTexas Christian UniversityFort WorthTexasUSA
| | - Joshua C. Carr
- Kinesiology DepartmentTexas Christian UniversityFort WorthTexasUSA
- Department of Medical EducationTexas Christian University School of MedicineFort WorthTexasUSA
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18
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Carson RG. The multifinger force deficit: A protocol to detect incipient cognitive decline. J Am Geriatr Soc 2022; 70:1605-1608. [PMID: 35243612 PMCID: PMC9314021 DOI: 10.1111/jgs.17734] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 02/09/2022] [Accepted: 02/17/2022] [Indexed: 01/16/2023]
Affiliation(s)
- Richard G Carson
- Trinity College Institute of Neuroscience and School of Psychology, Trinity College Dublin, Dublin, Ireland.,School of Psychology, Queen's University Belfast, Belfast, UK.,School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Australia
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19
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SAWAI A, ENDO M, SUZUKI Y, WATANABE K, SAWAI S, YAMASUE K, BANNAI Y, TAKEDA Y, FUJIKAWA T, OHNO M, FUJII H, TOCHIKUBO O. Relationship between the evaluation of lifestyle factors of elderly people as measured by the Health Wrist Watch and the health index. GAZZETTA MEDICA ITALIANA ARCHIVIO PER LE SCIENZE MEDICHE 2022. [DOI: 10.23736/s0393-3660.19.04246-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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20
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Naughton M, McLean S, Scott TJ, Weaving D, Solomon C. Quantifying Fatigue in the Rugby Codes: The Interplay Between Collision Characteristics and Neuromuscular Performance, Biochemical Measures, and Self-Reported Assessments of Fatigue. Front Physiol 2021; 12:711634. [PMID: 34776996 PMCID: PMC8586499 DOI: 10.3389/fphys.2021.711634] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 09/30/2021] [Indexed: 11/25/2022] Open
Abstract
Locomotor and collision actions that rugby players complete during match-play often lead to substantial fatigue, and in turn, delays in recovery. The methods used to quantify post-match fatigue and recovery can be categorised as subjective and objective, with match-related collision characteristics thought to have a primary role in modulating these recovery measures. The aim of this review was to (1) evaluate how post-match recovery has been quantified in the rugby football codes (i.e., rugby league, rugby union, and rugby sevens), (2) to explore the time-course of commonly used measures of fatigue post-match, and (3) to investigate the relationships between game-related collisions and fatigue metrics. The available evidence suggests that upper-, and lower-body neuromuscular performance are negatively affected, and biomarkers of muscular damage and inflammation increase in the hours and days following match-play, with the largest differences being at 12–36 h post-match. The magnitude of such responses varies within and between neuromuscular performance (Δ ≤ 36%, n = 13 studies) and tissue biomarker (Δ ≤ 585%, n = 18 studies) measures, but nevertheless appears strongly related to collision frequency and intensity. Likewise, the increase in perceived soreness in the hours and days post-match strongly correlate to collision characteristics across the rugby football codes. Within these findings, there are specific differences in positional groups and recovery trajectories between the codes which relate to athlete characteristics, and/or locomotor and collision characteristics. Finally, based on these findings, we offer a conceptual model of fatigue which details the multidimensional latent structure of the load to fatigue relationship contextualised to rugby. Research to date has been limited to univariate associations to explore relationships between collision characteristics and recovery, and multivariate methods are necessary and recommended to account for the latent structures of match-play external load and post-match fatigue constructs. Practitioners should be aware of the typical time windows of fatigue recovery and utilise both subjective and objective metrics to holistically quantify post-match recovery in rugby.
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Affiliation(s)
- Mitchell Naughton
- School of Health and Behavioural Sciences, University of the Sunshine Coast, Sippy Downs, QLD, Australia.,Centre for Human Factors and Sociotechnical Systems, University of the Sunshine Coast, Sippy Downs, QLD, Australia
| | - Scott McLean
- Centre for Human Factors and Sociotechnical Systems, University of the Sunshine Coast, Sippy Downs, QLD, Australia
| | - Tannath J Scott
- New South Wales Rugby League, Sydney Olympic Park, NSW, Australia.,Carnegie Applied Rugby Research Centre, Leeds Beckett University, Leeds, United Kingdom
| | - Dan Weaving
- Carnegie Applied Rugby Research Centre, Leeds Beckett University, Leeds, United Kingdom.,Leeds Rhinos Rugby League Club, Leeds, United Kingdom
| | - Colin Solomon
- School of Health and Behavioural Sciences, University of the Sunshine Coast, Sippy Downs, QLD, Australia.,Centre for Human Factors and Sociotechnical Systems, University of the Sunshine Coast, Sippy Downs, QLD, Australia
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21
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Lynch AE, Davies RW, Jakeman PM, Locke T, Allardyce JM, Carson BP. The Influence of Maximal Strength and Knee Angle on the Reliability of Peak Force in the Isometric Squat. Sports (Basel) 2021; 9:sports9100140. [PMID: 34678921 PMCID: PMC8539608 DOI: 10.3390/sports9100140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/17/2021] [Accepted: 10/02/2021] [Indexed: 11/16/2022] Open
Abstract
This study aimed to investigate the test-retest reliability of peak force in the isometric squat across the strength spectrum using coefficient of variation (CV) and intra-class correlation coefficient (ICC). On two separate days, 59 healthy men (mean (SD) age 23.0 (4.1) years; height 1.79 (0.7) m; body mass 84.0 (15.2) kg) performed three maximal effort isometric squats in two positions (at a 120° and a 90° knee angle). Acceptable reliability was observed at both the 120° (CV = 7.5 (6.7), ICC = 0.960 [0.933, 0.977]) and 90° positions (CV = 9.2 (8.8), ICC = 0.920 [0.865, 0.953]). There was no relationship between peak force in the isometric squat and the test-retest reliability at either the 120° (r = 0.052, p = 0.327) or 90° (r = 0.014, p = 0.613) positions. A subgroup of subjects (n = 17) also completed the isometric squat test at a 65° knee angle. Acceptable reliability was observed in this position (CV = 9.6 (9.3), ICC = 0.916 [0.766, 0.970]) and reliability was comparable to the 120° and 90° positions. Therefore, we deem isometric squat peak force output to be a valid and reliable measure across the strength spectrum and in different isometric squat positions.
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Affiliation(s)
- Arthur E. Lynch
- Department of Physical Education and Sport Sciences, Faculty of Education and Health Sciences, University of Limerick, V94 T9PX Limerick, Ireland; (A.E.L.); (R.W.D.); (P.M.J.); (T.L.); (J.M.A.)
| | - Robert W. Davies
- Department of Physical Education and Sport Sciences, Faculty of Education and Health Sciences, University of Limerick, V94 T9PX Limerick, Ireland; (A.E.L.); (R.W.D.); (P.M.J.); (T.L.); (J.M.A.)
| | - Philip M. Jakeman
- Department of Physical Education and Sport Sciences, Faculty of Education and Health Sciences, University of Limerick, V94 T9PX Limerick, Ireland; (A.E.L.); (R.W.D.); (P.M.J.); (T.L.); (J.M.A.)
| | - Tim Locke
- Department of Physical Education and Sport Sciences, Faculty of Education and Health Sciences, University of Limerick, V94 T9PX Limerick, Ireland; (A.E.L.); (R.W.D.); (P.M.J.); (T.L.); (J.M.A.)
| | - Joanna M. Allardyce
- Department of Physical Education and Sport Sciences, Faculty of Education and Health Sciences, University of Limerick, V94 T9PX Limerick, Ireland; (A.E.L.); (R.W.D.); (P.M.J.); (T.L.); (J.M.A.)
- Health Research Institute, University of Limerick, V94 T9PX Limerick, Ireland
| | - Brian P. Carson
- Department of Physical Education and Sport Sciences, Faculty of Education and Health Sciences, University of Limerick, V94 T9PX Limerick, Ireland; (A.E.L.); (R.W.D.); (P.M.J.); (T.L.); (J.M.A.)
- Health Research Institute, University of Limerick, V94 T9PX Limerick, Ireland
- Correspondence: ; Tel.: +353-(0)61-234943
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22
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Shouting strengthens maximal voluntary force and is associated with augmented pupillary dilation. Sci Rep 2021; 11:18419. [PMID: 34531493 PMCID: PMC8445920 DOI: 10.1038/s41598-021-97949-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 09/01/2021] [Indexed: 11/11/2022] Open
Abstract
Previous research has demonstrated that human maximal voluntary force is generally limited by neural inhibition. Producing a shout during maximal exertion effort enhances the force levels of maximal voluntary contraction. However, the mechanisms underlying this enhancement effect on force production remain unclear. We investigated the influence of producing a shout on the pupil-linked neuromodulatory system state by examining pupil size. We also examined its effects on the motor system state by examining motor evoked potentials in response to transcranial magnetic stimulation applied over the contralateral primary motor cortex, and by evaluating handgrip maximal voluntary force. Analysis revealed that producing a shout significantly increased handgrip maximal voluntary force, followed by an increase in pupil size and a reduction of the cortical silent period. Our results indicate that producing a shout increased handgrip maximal voluntary force through the enhancement of motor cortical excitability, possibly via the enhancement of noradrenergic system activity. This study provides evidence that the muscular force-enhancing effect of shouting during maximal force exertion is related to both the motor system state and the pupil-linked neuromodulatory system state.
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23
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Takarada Y, Nozaki D. The unconscious mental inhibiting process of human maximal voluntary contraction. PSYCHOLOGICAL RESEARCH 2021; 86:1458-1466. [PMID: 34398275 DOI: 10.1007/s00426-021-01578-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 08/05/2021] [Indexed: 10/20/2022]
Abstract
Human maximal voluntary contraction (MVC) is believed to be limited by neural inhibition. Motivational goal priming alters background states of the motor system, leading to enhanced MVC. However, the mechanisms that determine the constant inhibition of force exertion in the motor system remain unclear. The primary behavioural goal of MVC is maximal voluntary force exertion. The final expected or desired state of this behavioural goal is explicitly demonstrated with words related to physical exertion, such as 'maximal', irrespective of the possibility of demand-like properties in participants' minds, such as attainability and/or desirability of the goal. For the primed maximal goal state, most trial results fail to meet expectations, demonstrating negative affect that, without awareness, contributes to the mentioned inhibitory mechanism underlying MVC. We therefore speculated that the behavioural goal of MVC contributes to neural inhibitory mechanisms underlying MVC. In our study, we used a previously developed paradigm (Takarada and Nozaki in Scientific Reports 8: 10135, 2018) in which subliminal visual priming stimuli such as the physical exertion-related words "perform" and "exert" were presented to 12 healthy participants and were followed by supraliminal words that were the word "maximal" or neutral.We found that when combined with the term 'maximal' in the consciously visible form, the effect of this subliminal motor-goal priming in inducing pupil dilation and stronger action preparation/execution was abolished without conscious awareness. This is the first objective evidence of motor inhibitory effect-predicting patterns of pupil-linked noradrenergic activity as a signature of a type of mental inhibition underlying the MVC behavioural goal.
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Affiliation(s)
- Yudai Takarada
- Faculty of Sports Sciences, Waseda University, 2-579-15, Mikajima, Tokorozawa, Saitama, 359-1192, Japan.
| | - Daichi Nozaki
- Graduate School of Education, The University of Tokyo, Tokyo, 113-0033, Japan
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Mølmen KS, Hammarström D, Pedersen K, Lian Lie AC, Steile RB, Nygaard H, Khan Y, Hamarsland H, Koll L, Hanestadhaugen M, Eriksen AL, Grindaker E, Whist JE, Buck D, Ahmad R, Strand TA, Rønnestad BR, Ellefsen S. Vitamin D 3 supplementation does not enhance the effects of resistance training in older adults. J Cachexia Sarcopenia Muscle 2021; 12:599-628. [PMID: 33788419 PMCID: PMC8200443 DOI: 10.1002/jcsm.12688] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 12/30/2020] [Accepted: 01/26/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Lifestyle therapy with resistance training is a potent measure to counteract age-related loss in muscle strength and mass. Unfortunately, many individuals fail to respond in the expected manner. This phenomenon is particularly common among older adults and those with chronic diseases (e.g. chronic obstructive pulmonary disease, COPD) and may involve endocrine variables such as vitamin D. At present, the effects of vitamin D supplementation on responses to resistance training remain largely unexplored. METHODS Ninety-five male and female participants (healthy, n = 71; COPD, n = 24; age 68 ± 5 years) were randomly assigned to receive either vitamin D3 or placebo supplementation for 28 weeks in a double-blinded manner (latitude 61°N, September-May). Seventy-eight participants completed the RCT, which was initiated by 12 weeks of supplementation-only (two weeks with 10 000 IU/day, followed by 2000 IU/day), followed by 13 weeks of combined supplementation (2000 IU/day) and supervised whole-body resistance training (twice weekly), interspersed with testing and measurements. Outcome measures included multiple assessments of muscle strength (nvariables = 7), endurance performance (n = 6), and muscle mass (n = 3, legs, primary), as well as muscle quality (legs), muscle biology (m. vastus lateralis; muscle fibre characteristics, transcriptome), and health-related variables (e.g. visceral fat mass and blood lipid profile). For main outcome domains such as muscle strength and muscle mass, weighted combined factors were calculated from the range of singular assessments. RESULTS Overall, 13 weeks of resistance training increased muscle strength (13% ± 8%), muscle mass (9% ± 8%), and endurance performance (one-legged, 23% ± 15%; whole-body, 8% ± 7%), assessed as weighted combined factors, and were associated with changes in health variables (e.g. visceral fat, -6% ± 21%; [LDL]serum , -4% ± 14%) and muscle tissue characteristics such as fibre type proportions (e.g. IIX, -3% points), myonuclei per fibre (30% ± 65%), total RNA/rRNA abundances (15%/6-19%), and transcriptome profiles (e.g. 312 differentially expressed genes). Vitamin D3 supplementation did not affect training-associated changes for any of the main outcome domains, despite robust increases in [25(OH)D]serum (∆49% vs. placebo). No conditional effects were observed for COPD vs. healthy or pre-RCT [25(OH)D]serum . In secondary analyses, vitamin D3 affected expression of gene sets involved in vascular functions in muscle tissue and strength gains in participants with high fat mass, which advocates further study. CONCLUSIONS Vitamin D3 supplementation did not affect muscular responses to resistance training in older adults with or without COPD.
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Affiliation(s)
- Knut Sindre Mølmen
- Section for Health and Exercise PhysiologyInland Norway University of Applied SciencesLillehammerNorway
| | - Daniel Hammarström
- Section for Health and Exercise PhysiologyInland Norway University of Applied SciencesLillehammerNorway
| | - Karianne Pedersen
- Section for Health and Exercise PhysiologyInland Norway University of Applied SciencesLillehammerNorway
| | - Anne Cecilie Lian Lie
- Section for Health and Exercise PhysiologyInland Norway University of Applied SciencesLillehammerNorway
| | - Ragnvald B. Steile
- Section for Health and Exercise PhysiologyInland Norway University of Applied SciencesLillehammerNorway
| | - Håvard Nygaard
- Section for Health and Exercise PhysiologyInland Norway University of Applied SciencesLillehammerNorway
| | - Yusuf Khan
- Section for Health and Exercise PhysiologyInland Norway University of Applied SciencesLillehammerNorway
- Department of BiotechnologyInland Norway University of Applied SciencesHamarNorway
| | - Håvard Hamarsland
- Section for Health and Exercise PhysiologyInland Norway University of Applied SciencesLillehammerNorway
| | - Lise Koll
- Innlandet Hospital TrustLillehammerNorway
| | | | | | - Eirik Grindaker
- Section for Health and Exercise PhysiologyInland Norway University of Applied SciencesLillehammerNorway
| | | | - Daniel Buck
- Section for Health and Exercise PhysiologyInland Norway University of Applied SciencesLillehammerNorway
| | - Rafi Ahmad
- Department of BiotechnologyInland Norway University of Applied SciencesHamarNorway
- Institute of Clinical Medicine, Faculty of Health SciencesUiT – The Arctic University of NorwayTromsøNorway
| | - Tor A. Strand
- Innlandet Hospital TrustLillehammerNorway
- Centre for International HealthUniversity of BergenBergenNorway
| | - Bent R. Rønnestad
- Section for Health and Exercise PhysiologyInland Norway University of Applied SciencesLillehammerNorway
| | - Stian Ellefsen
- Section for Health and Exercise PhysiologyInland Norway University of Applied SciencesLillehammerNorway
- Innlandet Hospital TrustLillehammerNorway
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25
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Kishimoto KC, Héroux ME, Gandevia SC, Butler JE, Diong J. Estimation of maximal muscle electromyographic activity from the relationship between muscle activity and voluntary activation. J Appl Physiol (1985) 2021; 130:1352-1361. [PMID: 33600280 DOI: 10.1152/japplphysiol.00557.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Maximal muscle activity recorded with surface electromyography (EMG) is an important neurophysiological measure. It is frequently used to normalize EMG activity recorded during passive or active movement. However, the true maximal muscle activity cannot be determined in people with impaired capacity to voluntarily activate their muscles. Here, we determined whether maximal muscle activity can be estimated from muscle activity produced during submaximal voluntary activation. Twenty-five able-bodied adults (18 males, mean age 29 yr, range 19-64 yr) participated in the study. Participants were seated with the knee flexed 90° and the ankle in 5° of dorsiflexion from neutral. Participants performed isometric voluntary ankle plantarflexion contractions at target torques, in random order: 1, 5, 10, 15, 25, 50, 75, 90, 95, and 100% of maximal voluntary torque. Ankle torque, muscle activity in soleus, medial and lateral gastrocnemius muscles, and voluntary muscle activation determined using twitch interpolation were recorded. There was a strong loge-linear relationship between measures of muscle activation and muscle activity in all three muscles tested. Linear mixed models were fitted to muscle activation and loge-transformed EMG data. Each 1% increase in muscle activation increased muscle activity by a mean of 0.027 ln(mV) [95% confidence interval (CI) 0.025 to 0.029 ln(mV)] in soleus, 0.025 ln(mV) [0.022 to 0.028 ln(mV)] in medial gastrocnemius, and 0.028 ln(mV) [0.026 to 0.030 ln(mV)] in lateral gastrocnemius. The relationship between voluntary muscle activation and muscle activity can be described with simple mathematical functions. In future, it should be possible to normalize recorded muscle activity using these types of functions.NEW & NOTEWORTHY Muscle activity is often normalized to maximal muscle activity; however, it is difficult to obtain accurate measures of maximal muscle activity in people with impaired voluntary neural drive. We determined the relationship between voluntary muscle activation and plantarflexor muscle activity across a broad range of muscle activation values in able-bodied people. The relationship between voluntary muscle activation and muscle activity can be described with simple mathematical functions capable of estimating maximal muscle activity.
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Affiliation(s)
- Kenzo C Kishimoto
- Discipline of Physiotherapy, Faculty of Health Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Martin E Héroux
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia.,School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Simon C Gandevia
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia.,Prince of Wales Clinical School, University of New South Wales, Sydney, New South Wales, Australia
| | - Jane E Butler
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia.,School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Joanna Diong
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia.,Discipline of Anatomy and Histology, Faculty of Medicine and Health, School of Medical Sciences, The University of Sydney, Sydney, New South Wales, Australia
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26
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Nuzzo JL. History of Strength Training Research in Man: An Inventory and Quantitative Overview of Studies Published in English Between 1894 and 1979. J Strength Cond Res 2021; 35:1425-1448. [PMID: 33629976 DOI: 10.1519/jsc.0000000000003959] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Nuzzo, JL. History of strength training research in man: an inventory and quantitative overview of studies published in English between 1894 and 1979. J Strength Cond Res 35(5): 1425-1448, 2021-Limited scholarship exists on the history of strength training research. The current review advances existing qualitative and biographical work by inventorying all experimental studies and case reports published before 1980 on the effects of ≥1 week of strength training on human health and function. Data on authors, journals, citations, study samples, training interventions, study outcomes, and study themes were extracted and summarized. Three hundred thirty-nine strength training studies were published between 1894 and 1979. Studies included 14,575 subjects, with 10,350 undergoing strength training. Subjects were usually healthy (81.1% of articles), university students (51.0%), or aged 18-65 years (86.7%). Men comprised 70.0% of subjects. Interventions typically involved isoinertial only (64.6%) or isometric only (35.4%) training. Upper-body interventions were more common (35.4%) than lower-body interventions (27.4%). Duration and frequency of training were typically 4-8 weeks (55.3%) and 3 days per week (39.2%), respectively. Isometric maximal voluntary contractions (54.0%) and one repetition maximum (20.4%) were the most common muscle strength tests. Other common outcomes included limb girths (20.9%) and muscle endurance (19.5%). Common research themes were physiology (54.3%), physical fitness (28.9%), and injury/rehabilitation (20.4%). The 339 studies have been cited 21,996 times. Moritani and deVries' 1979 article on time course of neuromuscular adaptations is the most highly cited (1,815 citations). DeLorme (5 articles and 772 citations), Hellebrandt (4 articles and 402 citations), Rasch (9 articles and 318 citations), and Berger (12 articles and 1,293 citations) made the largest contributions. Research Quarterly published the most articles (27.4%). The history of strength training research is discussed in the context of the results.
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Affiliation(s)
- James L Nuzzo
- Independent researcher, West Leederville, Western Australia
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27
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Nuzzo JL, Kennedy DS, Finn HT, Taylor JL. Voluntary activation of knee extensor muscles with transcranial magnetic stimulation. J Appl Physiol (1985) 2021; 130:589-604. [PMID: 33270515 DOI: 10.1152/japplphysiol.00717.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We examined if transcranial magnetic stimulation (TMS) is a valid tool for assessment of voluntary activation of the knee extensors in healthy individuals. Maximal M-waves (Mmax) of vastus lateralis (VL) were evoked with electrical stimulation of femoral nerve (FNS); Mmax of medial hamstrings (HS) was evoked with electrical stimulation of sciatic nerve branches; motor evoked potentials (MEPs) of VL and HS were evoked with TMS; superimposed twitches (SIT) of knee extensors were evoked with FNS and TMS. In study 1, TMS intensity [69% output (SD: 5)] was optimized for MEP sizes, but guidelines for test validity could not be met. Agonist VL MEPs were too small [51.4% Mmax (SD: 11.9); guideline ≥70% Mmax] and antagonist HS MEPs were too big [16.5% Mmax (SD: 10.3); guideline <10% Mmax]. Consequently, the TMS estimated resting twitch [99.1 N (SD: 37.2)] and FNS resting twitch [142.4 N (SD: 41.8)] were different. In study 2, SITs at 90% maximal voluntary contraction (MVC) were similar between TMS [16.1 N (SD: 10.3)] and FNS [20.9 N (SD: 16.7)], when TMS intensity was optimized for this purpose, suggesting a procedure that combines TMS SITs with FNS resting twitches could be valid. In study 3, which tested the TMS intensity [56% output (SD: 18)] that evoked the largest SIT at 90% MVC, voluntary activation from TMS [87.3% (SD: 7.1)] and FNS [84.5% (SD: 7.6)] was different. In sum, the contemporary procedure for TMS-based voluntary activation of the knee extensors is invalid. A modified procedure improves validity but only in individuals who meet rigorous inclusion criteria for SITs and MEPs.NEW & NOTEWORTHY We discovered that the contemporary procedure for assessing voluntary activation of the knee extensor muscles with transcranial magnetic stimulation (TMS) is invalid. TMS activates too few agonist quadriceps motoneurons and too many antagonist hamstrings motoneurons to estimate the resting twitch accurately. A modified procedure, in which TMS-evoked superimposed twitches are considered together with the resting twitch from femoral nerve stimulation, is valid but only in select individuals who meet rigorous eligibility criteria.
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Affiliation(s)
- James L Nuzzo
- Neuroscience Research Australia, Randwick, Australia
| | - David S Kennedy
- Graduate School of Health, University of Technology Sydney, Sydney, Australia
| | | | - Janet L Taylor
- Neuroscience Research Australia, Randwick, Australia.,School of Medical and Health Sciences, Edith Cowan University, Perth, Australia
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Girts RM, MacLennan RJ, Harmon KK, Stock MS. Is skeletal muscle echo intensity more indicative of voluntary or involuntary strength in young women? TRANSLATIONAL SPORTS MEDICINE 2021. [DOI: 10.1002/tsm2.234] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Ryan M. Girts
- Neuromuscular Plasticity Laboratory School of Kinesiology and Physical Therapy University of Central Florida Orlando FL USA
- Institute of Exercise Physiology and Rehabilitation Science University of Central Florida Orlando FL USA
| | - Rob J. MacLennan
- Applied Neuromuscular Physiology Laboratory Oklahoma State University Stillwater OK USA
| | - Kylie K. Harmon
- Neuromuscular Plasticity Laboratory School of Kinesiology and Physical Therapy University of Central Florida Orlando FL USA
- Institute of Exercise Physiology and Rehabilitation Science University of Central Florida Orlando FL USA
| | - Matt S. Stock
- Neuromuscular Plasticity Laboratory School of Kinesiology and Physical Therapy University of Central Florida Orlando FL USA
- Institute of Exercise Physiology and Rehabilitation Science University of Central Florida Orlando FL USA
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29
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Reliability of Tibialis Anterior Muscle Voluntary Activation Using the Interpolated Twitch Technique and the Central Activation Ratio in People with Stroke. Brain Sci 2021; 11:brainsci11020176. [PMID: 33535411 PMCID: PMC7912757 DOI: 10.3390/brainsci11020176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 01/24/2021] [Accepted: 01/26/2021] [Indexed: 12/04/2022] Open
Abstract
Voluntary activation (VA) is measured by applying supramaximal electrical stimulation to a muscle during a maximal voluntary contraction (MVC). The amplitude of the evoked muscle twitch is used to determine any VA deficit, and indicates incomplete central neural drive to the motor units. People with stroke experience VA deficits and greater levels of central fatigue, which is the decrease in VA that occurs following exercise. This study investigated the between-session reliability of VA and central fatigue of the tibialis anterior muscle (TA) in people with chronic stroke (n = 12), using the interpolated twitch technique (ITT), adjusted-ITT, and central activation ratio (CAR) methods. On two separate sessions, supramaximal electrical stimulation was applied to the TA when it was at rest and maximally activated, at the start and end of a 30-s isometric dorsiflexor MVC. The most reliable measures of VA were obtained using the CAR calculation on transformed data, which produced an ICC of 0.92, and a lower bound confidence interval in the good range (95% CI 0.77 to 0.98). Reliability was lower for the CAR calculation on non-transformed data (ICC 0.82, 95% CI 0.63 to 0.91) and the ITT and adjusted-ITT calculations on transformed data (ICCs 0.82, 95% CIs 0.51 to 0.94), which had lower bound confidence intervals in the moderate range. The two ITT calculations on non-transformed data demonstrated the poorest reliability (ICCs 0.62, 95% CI 0.25 to 0.74). Central fatigue measures demonstrated very poor reliability. Thus, the reliability for VA in people with chronic stroke ranged from good to poor, depending on the calculation method and statistical analysis method, whereas the reliability for central fatigue was very poor.
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30
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Hortobágyi T, Granacher U, Fernandez-Del-Olmo M, Howatson G, Manca A, Deriu F, Taube W, Gruber M, Márquez G, Lundbye-Jensen J, Colomer-Poveda D. Functional relevance of resistance training-induced neuroplasticity in health and disease. Neurosci Biobehav Rev 2020; 122:79-91. [PMID: 33383071 DOI: 10.1016/j.neubiorev.2020.12.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 12/18/2020] [Accepted: 12/19/2020] [Indexed: 01/13/2023]
Abstract
Repetitive, monotonic, and effortful voluntary muscle contractions performed for just a few weeks, i.e., resistance training, can substantially increase maximal voluntary force in the practiced task and can also increase gross motor performance. The increase in motor performance is often accompanied by neuroplastic adaptations in the central nervous system. While historical data assigned functional relevance to such adaptations induced by resistance training, this claim has not yet been systematically and critically examined in the context of motor performance across the lifespan in health and disease. A review of muscle activation, brain and peripheral nerve stimulation, and imaging data revealed that increases in motor performance and neuroplasticity tend to be uncoupled, making a mechanistic link between neuroplasticity and motor performance inconclusive. We recommend new approaches, including causal mediation analytical and hypothesis-driven models to substantiate the functional relevance of resistance training-induced neuroplasticity in the improvements of gross motor function across the lifespan in health and disease.
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Affiliation(s)
- Tibor Hortobágyi
- Center for Human Movement Sciences, University of Groningen, University Medical CenterGroningen, Groningen, Netherlands.
| | - Urs Granacher
- Division of Training and Movement Sciences, Research Focus Cognition Sciences, University of Potsdam, Potsdam, Germany
| | - Miguel Fernandez-Del-Olmo
- Area of Sport Sciences, Faculty of Sports Sciences and Physical Education, Center for Sport Studies, King Juan Carlos University, Madrid, Spain
| | - Glyn Howatson
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle, UK; Water Research Group, North West University, Potchefstroom, South Africa
| | - Andrea Manca
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Franca Deriu
- Department of Biomedical Sciences, University of Sassari, Sassari, Italy
| | - Wolfgang Taube
- Department of Neurosciences and Movement Sciences, University of Fribourg, Fribourg, Switzerland
| | - Markus Gruber
- Human Performance Research Centre, Department of Sport Science, University of Konstanz, Konstanz, Germany
| | - Gonzalo Márquez
- Department of Physical Education and Sport, Faculty of Sports Sciences and Physical Education, University of A Coruña, A Coruña, Spain
| | - Jesper Lundbye-Jensen
- Movement & Neuroscience, Department of Nutrition, Exercise & Sports Department of Neuroscience, University of Copenhagenk, Faculty of Health Science, Universidad Isabel I, Burgos, Spain
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31
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Mota JA, Kwon DP, Kennedy M, Sobolewski EJ, Kim Y, Gonzales JU, Stock MS. Compensatory adjustments in motor unit behavior during fatigue differ for younger versus older men. Aging Clin Exp Res 2020; 32:2259-2269. [PMID: 31898169 DOI: 10.1007/s40520-019-01438-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 12/03/2019] [Indexed: 10/25/2022]
Abstract
BACKGROUND The ability to maintain a submaximal force as a muscle fatigues is supplemented by compensatory adjustments in the nervous system's control of motor units. AIM We sought to compare vastus lateralis motor unit recruitment and firing rate data for younger versus older men during isometric fatigue. METHODS Twelve younger (age = 25 ± 3 years) and 12 older (75 ± 8 years) men performed contractions of the knee extensors at 50% of maximal voluntary contraction force until exhaustion. Surface electromyographic (sEMG) signals were detected from the vastus lateralis. A sEMG signal decomposition algorithm was used to quantify the motor unit action potential (MUAP) amplitude, mean firing rates, and recruitment threshold of each motor unit. For the latter two variables, our analyses only included motor units that featured similar action potential amplitude throughout the protocol. RESULTS There was no group difference for time to task failure (p = 0.362, d = 0.381). Both groups showed increases in MUAP amplitude [younger and older slopes = 0.0174 ± 0.0123 and 0.0073 ± 0.0123 mV/contraction, respectively (p = 0.082, d = 0.710)], but the change was more linear for the younger men (mean r2 values = 0.565 and 0.455). Mean firing rates increased over time for the younger (p < 0.001), but not the older (p = 0.579), men. Similarly, recruitment thresholds decreased for younger men (p = 0.001). CONCLUSION We propose that aging results in neuromuscular impairments that hinder older adults' ability to make compensatory adjustments in motor unit control during fatigue.
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Ramsook AH, Molgat-Seon Y, Boyle KG, Mitchell RA, Puyat JH, Koehle MS, Sheel AW, Guenette JA. Reliability of diaphragm voluntary activation measurements in healthy adults. Appl Physiol Nutr Metab 2020; 46:247-256. [PMID: 32910865 DOI: 10.1139/apnm-2020-0221] [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] [Indexed: 11/22/2022]
Abstract
Voluntary activation can be used to assess central fatigue of the diaphragm after tasks such as exercise or inspiratory muscle loading. Cervical magnetic stimulation (CMS) of the phrenic nerves elicits an involuntary contraction, or twitch, of the diaphragm. This twitch is quantified based on a measure of transdiaphragmatic pressure and can be used to evaluate diaphragm contractile function and diaphragm voluntary activation (diaphragm-VA). The test-retest reliability of diaphragm-VA using CMS is currently unknown. Thirteen participants (4 male, 9 female; aged 25 ± 3 years) performed a series of interpolated twitch manoeuvres, which included a maximal inspiratory effort against a semi-occluded mouthpiece and 2 CMS-stimuli, 1 during the inspiratory manoeuvre and 1 after when the participant returned to functional residual capacity to quantify diaphragm-VA. Intraclass correlation coefficients (ICCs) and standard error of measurement (SEM) measured between-day and within-session reliability of diaphragm-VA, respectively. Maximal diaphragm-VA values were 91% (SD: 6; SEM: 3.9) and 92% (SD: 5; SEM: 2.2) during visits 1 and 2 (p = 0.68), respectively, and displayed "good" between-day reliability (ICC: 0.88; 95% confidence interval: 0.67-0.95; SEM: 2.7). Our results suggest that assessing diaphragm-VA using CMS is reliable in young healthy adults. Measuring diaphragm-VA may provide additional insight into the consequences and mechanisms of diaphragm fatigue. Novelty: Magnetic stimulation of the phrenic nerves can reliably measure voluntary activation of the diaphragm. Diaphragm voluntary activation can be used to provide additional insight into fatigability of the diaphragm.
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Affiliation(s)
- Andrew H Ramsook
- Department of Physical Therapy, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart Lung Innovation, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Yannick Molgat-Seon
- Department of Physical Therapy, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart Lung Innovation, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada.,Department of Kinesiology and Applied Health, Faculty of Kinesiology and Applied Health, The University of Winnipeg, Winnipeg, Manitoba, Canada
| | - Kyle G Boyle
- Department of Physical Therapy, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart Lung Innovation, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Reid A Mitchell
- Department of Physical Therapy, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart Lung Innovation, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Joseph H Puyat
- Centre for Health Evaluation and Outcome Services, Providence Health Care Research Institute, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada
| | - Michael S Koehle
- School of Kinesiology, Faculty of Education, The University of British Columbia, Vancouver, British Columbia, Canada.,Department of Family Practice, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada
| | - A William Sheel
- Centre for Heart Lung Innovation, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada.,School of Kinesiology, Faculty of Education, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Jordan A Guenette
- Department of Physical Therapy, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart Lung Innovation, The University of British Columbia and St. Paul's Hospital, Vancouver, British Columbia, Canada.,School of Kinesiology, Faculty of Education, The University of British Columbia, Vancouver, British Columbia, Canada
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33
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Tracking the corticospinal responses to strength training. Eur J Appl Physiol 2020; 120:783-798. [DOI: 10.1007/s00421-020-04316-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 02/03/2020] [Indexed: 01/07/2023]
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Hogrel JY, Benveniste O, Bachasson D. Routine monitoring of isometric knee extension strength in patients with muscle impairments using a new portable device: cross-validation against a standard isokinetic dynamometer. Physiol Meas 2020; 41:015003. [PMID: 31935703 DOI: 10.1088/1361-6579/ab6b49] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Muscle strength is a critical clinical hallmark in both health and disease. The current study introduces a novel portable device prototype (MyoQuad) for assessing and monitoring maximal voluntary isometric knee extension torque (MVIT). APPROACH Fifty-six patients with inclusion body myositis were studied. Knee extension weakness is a key feature in this inflammatory muscle disease. Cross-validation with an isokinetic dynamometer (Biodex System 3 Pro) was performed. Between-day reproducibility and ability to monitor changes in muscle strength over time compared to the gold standard method as a reference, were also investigated. MAIN RESULTS The measurement was feasible even in the weakest patients. Agreement between methods was excellent (standard error of measurement (SEM) was 3.8 Nm and intra-class correlation coefficient (ICC) was 0.973). Least significant difference (LSD) was 4.9 and 5.3 Nm for the MyoQuad and the Biodex, respectively Measurements using the MyoQuad exhibited excellent between-day reproducibility (SEM was 2.4 Nm and ICC was 0.989 versus 2.6 Nm and 0.988 using the Biodex). Changes in MVIT at 6 and 12 months were similar between methods (timepoint × method interaction was not significant; all p > 0.19); strength changes classified according to LSD at 6 and 12 months were consistent between methods (>70% consistent classification)). SIGNIFICANCE The measurement of MVIT using the MyoQuad offers a cost-effective, portable and immediate alternative for the routine measurement of maximal voluntary isometric strength of the quadriceps. The MyoQuad offers a comfort and stability that cannot be provided by standard hand-held dynamometers. These results support quantitative muscle strength assessment using fixed yet flexible dynamometry within clinical routine and multicenter trials.
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Affiliation(s)
- Jean-Yves Hogrel
- Institute of Myology, Neuromuscular Investigation Center, Pitié-Salpêtrière University Hospital, Paris, France. Author to whom any correspondence should be addressed
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Dos Santos WDN, Siqueira GDDJ, Martins WR, Vieira A, Schincaglia RM, Gentil P, Vieira CA. Reliability and Agreement of the 10-Repetition Maximum Test in Breast Cancer Survivors. Front Oncol 2019; 9:918. [PMID: 31616633 PMCID: PMC6775190 DOI: 10.3389/fonc.2019.00918] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 09/03/2019] [Indexed: 01/28/2023] Open
Abstract
The aim of this study was to evaluate the reliability and agreement between the test and retest of the 10-repetition maximum (10-RM) test for leg press and bench press in breast cancer survivors (BCS). Thirty-one BCS participated in this study, age 54.87 ± 5.7 years. All performed 10-RM tests and retests for the leg press 45° and the bench press. For reliability analyses, an intraclass coefficient correlation (ICC) and coefficient of variation (CV) were performed. The limits of agreement were calculated using a Bland-Altman plot with 95% CIs. For absolute and relative error of measurement, we used standard error of measurement and minimally detectable change. The result showed a high reliability for the bench press and leg press; ICC of 0.94 and 0.98, respectively. CV was <10% for both exercises. The systematic error were 1.5 kg (10%) and 6.1 (8%) for the bench press and leg press, respectively. The standard errors of measurements were 0.96 kg (6.08%) and 4.11 kg (5.27%) for the bench press and leg press, respectively. The minimally detectable changes were 2.72 kg (17.20%) and 5.62 kg (7.21%) for the bench press and leg press, respectively. In breast cancer survivors, the muscular strength measurement for the 10-RM test showed a high to very high rate of reliability and agreement, with acceptable error of measurement.
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Affiliation(s)
| | | | | | - Amilton Vieira
- College of Physical Education, University of Brasilia - UnB, Brasilia, Brazil
| | | | - Paulo Gentil
- College of Physical Education and Dance, Federal University of Goias - UFG, Goiânia, Brazil
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Swafford AP, Kwon DP, MacLennan RJ, Fukuda DH, Stout JR, Stock MS. No acute effects of placebo or open-label placebo treatments on strength, voluntary activation, and neuromuscular fatigue. Eur J Appl Physiol 2019; 119:2327-2338. [PMID: 31468171 DOI: 10.1007/s00421-019-04219-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 08/25/2019] [Indexed: 12/17/2022]
Abstract
PURPOSE Recent evidence suggests that deception may not be necessary for placebos to improve clinical outcomes. We tested the hypothesis that placebo and open-label placebo (OLP) treatments would acutely improve strength and voluntary activation, as well as minimize neuromuscular fatigue, in untrained participants. METHODS Twenty-one males (n = 11) and females (n = 10) visited the laboratory on three occasions (placebo, OLP, control) to receive each treatment in a randomized, counter-balanced manner. Trials involved a pretest, a 15-min intervention, and posttests. For the placebo trial, participants were informed that they would be ingesting a capsule that would improve their performance and make them feel more energetic. For the OLP intervention, participants were told that the capsules would have no effects. In "Experiment #1", knee extensor maximal voluntary contraction (MVC) peak torque and percent voluntary activation were evaluated. In "Experiment #2", participants performed 20 consecutive MVCs while surface electromyographic signals were detected from the vastus lateralis. Subjective assessments of energy and perceived exertion were examined. RESULTS The interventions had no effect on strength or voluntary activation, but energy levels increased following treatments (p = 0.016, η2 = 0.257). Neither treatment influenced neuromuscular fatigue. Though some variables showed moderate-to-large effect sizes, these results were consistent for individuals with lower voluntary activation. CONCLUSION Placebo and OLP treatments had minimal influence on strength, voluntary activation, and fatigue resistance. As these findings differ from recent reports, we speculate that placebos and OLPs are more likely to enhance muscle function in patient populations seeking medical care.
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Affiliation(s)
- Alina P Swafford
- School of Kinesiology and Physical Therapy, College of Health Professions and Sciences, University of Central Florida, 12805 Pegasus Drive, HPA 1, Room 258, Orlando, FL, 32816-2205, USA
| | - Dennis P Kwon
- School of Kinesiology and Physical Therapy, College of Health Professions and Sciences, University of Central Florida, 12805 Pegasus Drive, HPA 1, Room 258, Orlando, FL, 32816-2205, USA
| | - Rob J MacLennan
- School of Kinesiology and Physical Therapy, College of Health Professions and Sciences, University of Central Florida, 12805 Pegasus Drive, HPA 1, Room 258, Orlando, FL, 32816-2205, USA
| | - David H Fukuda
- School of Kinesiology and Physical Therapy, College of Health Professions and Sciences, University of Central Florida, 12805 Pegasus Drive, HPA 1, Room 258, Orlando, FL, 32816-2205, USA
| | - Jeffrey R Stout
- School of Kinesiology and Physical Therapy, College of Health Professions and Sciences, University of Central Florida, 12805 Pegasus Drive, HPA 1, Room 258, Orlando, FL, 32816-2205, USA
| | - Matt S Stock
- School of Kinesiology and Physical Therapy, College of Health Professions and Sciences, University of Central Florida, 12805 Pegasus Drive, HPA 1, Room 258, Orlando, FL, 32816-2205, USA.
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Hammond A, Perrin C, Steele J, Giessing J, Gentil P, Fisher JP. The effects of a 4-week mesocycle of barbell back squat or barbell hip thrust strength training upon isolated lumbar extension strength. PeerJ 2019; 7:e7337. [PMID: 31388473 PMCID: PMC6662562 DOI: 10.7717/peerj.7337] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 06/21/2019] [Indexed: 01/12/2023] Open
Abstract
Objectives Common exercises such as the barbell back squat (BBS) and barbell hip thrust (BHT) are perceived to provide a training stimulus to the lumbar extensors. However, to date there have been no empirical studies considering changes in lumbar extension strength as a result of BBS or BHT resistance training (RT) interventions. Purpose To consider the effects of BBS and BHT RT programmes upon isolated lumbar extension (ILEX) strength. Methods Trained male subjects (n = 14; 22.07 ± 0.62 years; 179.31 ± 6.96 cm; 79.77 ± 13.81 kg) were randomised in to either BBS (n = 7) or BHT (n = 7) groups and performed two training sessions per week during a 4-week mesocycle using 80% of their 1RM. All subjects were tested pre- and post-intervention for BBS and BHT 1RM as well as isometric ILEX strength. Results Analyses revealed that both BBS and BHT groups significantly improved both their BBS and BHT 1RM, suggesting a degree of transferability. However, the BBS group improved their BBS 1RM to a greater degree than the BHT group (p = 0.050; ∼11.8 kg/10.2% vs. ∼8.6 kg/7.7%, respectively). And the BHT group improved their BHT 1RM to a greater degree than the BBS group (p = 0.034; ∼27.5 kg/24.8% vs. ∼20.3 kg/13.3%, respectively). Neither BBS nor BHT groups significantly improved their isometric ILEX strength. Conclusions The present study supports the concept of specificity, particularly in relation to the movement mechanics between trunk extension (including pelvic rotation) and ILEX. Our data suggest that strength coaches, personal trainers, and trainees can self-select multi-joint lower-body trunk extension exercises based on preference or variety. However, evidence suggests that neither the BBS nor BHT exercises can meaningfully increase ILEX strength. Since strengthening these muscles might enhance physical and sporting performance we encourage strength coaches and personal trainers to prescribe ILEX exercise.
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Affiliation(s)
- Alexander Hammond
- School of Sport, Health and Social Sciences, Southampton Solent University, Southampton, UK
| | - Craig Perrin
- School of Sport, Health and Social Sciences, Southampton Solent University, Southampton, UK
| | - James Steele
- School of Sport, Health and Social Sciences, Southampton Solent University, Southampton, UK
| | - Jürgen Giessing
- Institute of Sport Science, Universität Koblenz-Landau, Landau, Germany
| | - Paulo Gentil
- Faculty of Physical Education and Dance, Universidade Federal de Goiás, Goiania, Brazil
| | - James P Fisher
- School of Sport, Health and Social Sciences, Southampton Solent University, Southampton, UK
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Diong J, Gandevia SC, Nguyen D, Foo Y, Kastre C, Andersson K, Butler JE, Héroux ME. Small amounts of involuntary muscle activity reduce passive joint range of motion. J Appl Physiol (1985) 2019; 127:229-234. [DOI: 10.1152/japplphysiol.00168.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
When assessing passive joint range of motion in neurological conditions, concomitant involuntary muscle activity is generally regarded small enough to ignore. This assumption is untested. If false, many clinical and laboratory studies that rely on these assessments may be in error. We determined to what extent small amounts of involuntary muscle activity limit passive range of motion in 30 able-bodied adults. Subjects were seated with the knee flexed 90° and the ankle in neutral, and predicted maximal plantarflexion torque was determined using twitch interpolation. Next, with the knee flexed 90° or fully extended, the soleus muscle was continuously electrically stimulated to generate 1, 2.5, 5, 7.5, and 10% of predicted maximal torque, in random order, while the ankle was passively dorsiflexed to a torque of 9 N·m by a blinded investigator. A trial without stimulation was also performed. Ankle dorsiflexion torque-angle curves were obtained at each percent of predicted maximal torque. On average (mean, 95% confidence interval), each 1% increase in plantarflexion torque decreases ankle range of motion by 2.4° (2.0 to 2.7°; knee flexed 90°) and 2.3° (2.0 to 2.5°; knee fully extended). Thus 5% of involuntary plantarflexion torque, the amount usually considered small enough to ignore, decreases dorsiflexion range of motion by ~12°. Our results indicate that even small amounts of involuntary muscle activity will bias measures of passive range and hinder the differential diagnosis and treatment of neural and nonneural mechanisms of contracture. NEW & NOTEWORTHY The soleus muscle in able-bodied adults was tetanically stimulated while the ankle was passively dorsiflexed. Each 1% increase in involuntary plantarflexion torque at the ankle decreases the range of passive movement into dorsiflexion by >2°. Thus the range of ankle dorsiflexion decreases by ~12° when involuntary plantarflexion torque is 5% of maximum, a torque that is usually ignored. Thus very small amounts of involuntary muscle activity substantially limit passive joint range of motion.
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Affiliation(s)
- Joanna Diong
- School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, New South Wales, Australia
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia
| | - Simon C. Gandevia
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia
- Prince of Wales Clinical School, University of New South Wales, New South Wales, Australia
| | - David Nguyen
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia
| | - Yanni Foo
- Faculty of Health Sciences, The University of Sydney, New South Wales, Australia
| | | | | | - Jane E. Butler
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, New South Wales, Australia
| | - Martin E. Héroux
- Neuroscience Research Australia (NeuRA), Sydney, New South Wales, Australia
- School of Medical Sciences, University of New South Wales, New South Wales, Australia
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Nuzzo JL, Finn HT, Herbert RD. Causal Mediation Analysis Could Resolve Whether Training-Induced Increases in Muscle Strength are Mediated by Muscle Hypertrophy. Sports Med 2019; 49:1309-1315. [DOI: 10.1007/s40279-019-01131-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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