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Jiří B, Jan G, Tomáš J, Patrik B, Andri F. Measuring critical force in sport climbers: a validation study of the 4 min all-out test on finger flexors. Eur J Appl Physiol 2024; 124:2787-2798. [PMID: 38668851 PMCID: PMC11365833 DOI: 10.1007/s00421-024-05490-7] [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: 02/09/2024] [Accepted: 04/15/2024] [Indexed: 09/02/2024]
Abstract
PURPOSE The critical force (CF) concept, differentiating steady and non-steady state conditions, extends the critical power paradigm for sport climbing. This study aimed to validate CF for finger flexors derived from the 4 min all-out test as a boundary for the highest sustainable work intensity in sport climbers. METHODS Twelve participants underwent multiple laboratory visits. Initially, they performed the 4 min intermittent contraction all-out test for CF determination. Subsequent verification visits involved finger-flexor contractions at various intensities, including CF, CF -2 kg, CF -4 kg, and CF -6 kg, lasting for 720 s or until failure, while monitoring muscle-oxygen dynamics of forearm muscles. RESULTS CF, determined from the mean force of last three contractions, was measured at 20.1 ± 5.7 kg, while the end-force at 16.8 ± 5.2 kg. In the verification trials, the mean time to failure at CF was 440 ± 140 s, with only one participant completing the 720 s task. When the load was continuously lowered (-2 kg, -4 kg, and -6 kg), a greater number of participants (38%, 69%, and 92%, respectively) successfully completed the 720 s task. Changes of muscle-oxygen dynamics showed a high variability and could not clearly distinguish between exhaustive and non-exhaustive trials. CONCLUSIONS CF, based on the mean force of the last three contractions, failed to reliably predict the highest sustainable work rate. In contrast, determining CF as the end-force of the last three contractions exhibited a stronger link to sustainable work. Caution is advised in interpreting forearm muscle-oxygen dynamics, lacking sensitivity for nuanced metabolic responses during climbing-related tasks.
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Affiliation(s)
- Baláš Jiří
- Faculty of Physical Education and Sport, Charles University, José Martího 31, 16252, Prague 6, Czech Republic.
| | - Gajdošík Jan
- Faculty of Physical Education and Sport, Charles University, José Martího 31, 16252, Prague 6, Czech Republic
| | - Javorský Tomáš
- Faculty of Physical Education and Sport, Charles University, José Martího 31, 16252, Prague 6, Czech Republic
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Berta Patrik
- Faculty of Physical Education and Sport, Charles University, José Martího 31, 16252, Prague 6, Czech Republic
| | - Feldmann Andri
- Institute of Sport Science, University of Bern, Bern, Switzerland
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Langer K, Simon C, Wiemeyer J. Physical performance testing in climbing-A systematic review. Front Sports Act Living 2023; 5:1130812. [PMID: 37229362 PMCID: PMC10203485 DOI: 10.3389/fspor.2023.1130812] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 04/17/2023] [Indexed: 05/27/2023] Open
Abstract
Due to the increasing popularity of climbing, the corresponding diagnostics are gaining in importance for both science and practice. This review aims to give an overview of the quality of different diagnostic testing- and measurement methods for performance, strength, endurance, and flexibility in climbing. A systematic literature search for studies including quantitative methods and tests for measuring different forms of strength, endurance, flexibility, or performance in climbing and bouldering was conducted on PubMed and SPORT Discus. Studies and abstracts were included if they a) worked with a representative sample of human boulderers and/or climbers, b) included detailed information on at least one test, and c) were randomized-controlled-, cohort-, cross-over-, intervention-, or case studies. 156 studies were included into the review. Data regarding subject characteristics, as well as the implementation and quality of all relevant tests were extracted from the studies. Tests with similar exercises were grouped and the information on a) measured value, b) unit, c) subject characteristics (sex and ability level), and d) quality criteria (objectivity, reliability, validity) were bundled and displayed in standardized tables. In total, 63 different tests were identified, of which some comprised different ways of implementation. This clearly shows that there are no uniform or standard procedures in climbing diagnostics, for tests on strength, endurance or flexibility. Furthermore, only few studies report data on test quality and detailed information on sample characteristics. This not only makes it difficult to compare test results, but at the same time makes it impossible to give precise test recommendations. Nevertheless, this overview of the current state of research contributes to the creation of more uniform test batteries in the future.
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Ginszt M, Saito M, Zięba E, Majcher P, Kikuchi N. Body Composition, Anthropometric Parameters, and Strength-Endurance Characteristics of Sport Climbers: A Systematic Review. J Strength Cond Res 2023; 37:1339-1348. [PMID: 36930882 DOI: 10.1519/jsc.0000000000004464] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
Abstract
ABSTRACT Ginszt, M, Saito, M, Zięba, E, Majcher, P, and Kikuchi, N. Body composition, anthropometric parameters, and strength-endurance characteristics of sport climbers: a systematic review. J Strength Cond Res XX(X): 000-000, 2023-Sport climbing was selected to be part of the Summer Olympic Games in Tokyo 2021 with 3 subdisciplines: lead climbing, speed climbing, and bouldering. The nature of physical effort while speed climbing, lead climbing, and bouldering performance is different. This literature review aimed to describe differences between body composition, anthropometric parameters, and upper-limb strength-endurance variables between sport climbers with different ability levels and nonclimbers. The following databases were searched: PubMed and Scopus. The following keywords were used: "sport climbing," "rock climbing," "lead climbing," and "bouldering." Articles were considered from January 2000 to October 2021 if they concerned at least one of the following parameters: body composition (mass, body mass index, body fat, lean muscle mass, bone mineral density), anthropometric parameters (height, ape index), muscle strength (MVC finger strength in half-crimp grip, MVC finger strength to body mass, handgrip strength), and muscle endurance (force time integral, pull-ups). A review shows that body mass and body fat content were lower in the sport climbers compared with controls and in elite sport climbers compared with those less advanced. Sport climbers presented higher values of MVC finger strength in half-crimp grip, MVC finger strength to body mass, handgrip strength, and force time integral parameter than control subjects. Significantly higher MVC values in half-crimp grip were observed in elite sport climbers than in advanced athletes. None of the analyzed work showed differences between sport climber groups in the ape index. The abovementioned parameters may be a key factor in elite sport climbing performance.
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Affiliation(s)
- Michał Ginszt
- Department of Rehabilitation and Physiotherapy, Medical University of Lublin, Lublin, Poland; and
| | - Mika Saito
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Estera Zięba
- Department of Rehabilitation and Physiotherapy, Medical University of Lublin, Lublin, Poland; and
| | - Piotr Majcher
- Department of Rehabilitation and Physiotherapy, Medical University of Lublin, Lublin, Poland; and
| | - Naoki Kikuchi
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
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Stien N, Saeterbakken AH, Andersen V. Tests and Procedures for Measuring Endurance, Strength, and Power in Climbing—A Mini-Review. Front Sports Act Living 2022; 4:847447. [PMID: 35308594 PMCID: PMC8931302 DOI: 10.3389/fspor.2022.847447] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Accepted: 01/27/2022] [Indexed: 12/04/2022] Open
Abstract
The interest in climbing is rapidly growing among professional and recreational athletes and will for the first time be included in the 2021 Tokyo Olympics. The sport has also gained increased scientific attention in the past decades. Still, recommendations for testing procedures to predict climbing performance and measure training effects are limited. Therefore, the aim of this mini-review is to provide an overview of the climbing-specific tests, procedures and outcomes used to examine climbing performance. The available literature presents a variety of tests and procedures. While the reliability of some tests has been examined, measures of validity are scarce, especially for climbing-specific endurance tests. Moreover, considering the possible combinations of climbing performance levels, disciplines, and tests, substantial gaps in the literature exist. Vague descriptions of the participants in many studies (e.g., not specifying preferred discipline, performance level, experience, and regular climbing and training volume) further limit the current knowledge and challenge comparisons across studies. Regarding contraction types, dynamic strength- and power-tests are underrepresented in the literature compared to isometric tests. Studies exploring and reporting the validity and reliability of climbing-specific tests are warranted, and researchers should strive to provide a detailed description of the study populations in future research.
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Honorato RDC, Franchini E, Lara JPR, Fonteles AI, Pinto JCBDL, Mortatti AL. Differences in Handgrip Strength-Endurance and Muscle Activation Between Young Male Judo Athletes and Untrained Individuals. RESEARCH QUARTERLY FOR EXERCISE AND SPORT 2021; 92:1-10. [PMID: 32023202 DOI: 10.1080/02701367.2019.1699233] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Accepted: 11/22/2019] [Indexed: 06/10/2023]
Abstract
Purpose: The aim of this study was to compare strength-endurance handgrip performance and muscle coactivation between judo athletes and untrained young males. Method: The sample was 38 judo athletes and 38 untrained young males, between 12 and 15 years-old. Maturational status was evaluated by age at peak height velocity. A maximal isometric handgrip test (three 5-s repetitions, with 90-s intervals) and an isometric strength-endurance handgrip test (ten 10-s all-out isometric handgrip repetitions, 20-s intervals) was conducted in dominant (D) and nondominant (ND) hands, using a dynamometer with EMG monitor to detect muscle activation. Results: ANCOVA analysis, controlling for maturational status, showed that judo athletes had higher values of maximal absolute (D = 33.6 ± 8.9 kgf vs 29.1 ± 9.0 kgf; ND = 33.8 ± 9.9 kgf vs 28.1 ± 8.1 kgf) and relative strength to body mass (D = 0.64 ± 0.12 kg/kgf vs 0.57 ± 0.13 kg/kgf; ND = 0.64 ± 0.16 kg/kgf vs 0.56 ± 0.14 kg/kgf). Moreover, judo athletes presented lower strength mean fatigue index (33.2 ± 6.9 % vs 37.9 ± 8.7 %) and muscle coactivation (48 ± 19.8 % vs 57.5 ± 22 %), only in the dominant hand, during the isometric strength-endurance handgrip test. During all repetitions of isometric endurance test there were no group or interaction between factors effects for absolute strength, relative strength and muscle coactivation. Conclusion: In summary, judo athletes present higher maximal absolute and relative strength and strength-endurance performance, concomitantly with decreased muscles co-activation (primary in dominant hand) during handgrip tests.
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Assmann M, Steinmetz G, Schilling AF, Saul D. Comparison of Grip Strength in Recreational Climbers and Non-Climbing Athletes-A Cross-Sectional Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 18:ijerph18010129. [PMID: 33375452 PMCID: PMC7796164 DOI: 10.3390/ijerph18010129] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/23/2020] [Accepted: 12/24/2020] [Indexed: 01/17/2023]
Abstract
In recent years, climbing sports is on the rise making its Olympic debut in 2021. Physiological traits of professional rock climbers have been intensively studied, while recreational indoor climbers are less investigated, especially regarding grip strength and upper extremity proportions. In this cross-sectional study, we aimed to understand what discerns the recreational climber from disparate recreational athletes. Therefore, we analyzed 50 recreational climbing (30.3 ± 12.7 years, 1.76 ± 0.09 m and 67.0 ± 14.0 kg) and 50 non-climbing athletes (26.4 ± 9.1 years, 1.78 ± 0.09 m and 73.2 ± 12.6 kg) to detect differences in their finger grip strength of seven different pinches. In addition, the upper extremity proportions were measured. Even in recreational climbers, almost all analyzed grips were stronger compared to other athletes (p < 0.05 in all but non-dominant fist, small to moderate effect sizes). Only the grip strength of the whole non-dominant hand was not significantly different (p = 0.17). Interestingly, differences between the dominant and non-dominant hand appeared to be larger in the non-climbing (all p < 0.05, all but one with small effect size) compared to the climbing cohort (pinch I/IV and pinch I/II+III+IV not different and mostly trivial). Circumference measurements showed that 10 cm below the lateral epicondyle, climbers exhibited significantly greater perimeter compared to non-climbing athletes (p < 0.05, small effect size). Our results show that recreational climbers have higher measured grip strength, but less profound differences between the dominant and non-dominant hand.
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Affiliation(s)
- Mara Assmann
- Department of Trauma, Orthopedics and Reconstructive Surgery, Georg-August-University of Goettingen, 37075 Goettingen, Germany; (M.A.); (G.S.); (A.F.S.)
| | - Gino Steinmetz
- Department of Trauma, Orthopedics and Reconstructive Surgery, Georg-August-University of Goettingen, 37075 Goettingen, Germany; (M.A.); (G.S.); (A.F.S.)
| | - Arndt Friedrich Schilling
- Department of Trauma, Orthopedics and Reconstructive Surgery, Georg-August-University of Goettingen, 37075 Goettingen, Germany; (M.A.); (G.S.); (A.F.S.)
| | - Dominik Saul
- Department of Trauma, Orthopedics and Reconstructive Surgery, Georg-August-University of Goettingen, 37075 Goettingen, Germany; (M.A.); (G.S.); (A.F.S.)
- Kogod Center on Aging and Division of Endocrinology, Mayo Clinic, Rochester, MN 55905, USA
- Correspondence:
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Nolan J, Mclennan PL, Peoples GE. Forearm isometric fatigue-resistance is enhanced in rock climbers compared to power lifters and aerobically-trained athletes. J Sports Med Phys Fitness 2020; 60:1057-1064. [PMID: 32955831 DOI: 10.23736/s0022-4707.20.10542-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Rock climbers are characterized by enhanced forearm fatigue resistance. This study compared the forearm isometric force of rock climbers (RC), strength-matched power lifters (PL) and aerobically trained (AT) athletes to determine the contribution of muscle oxygen desaturation during ischemia. METHODS Aerobically trained athletes (N.=6, 23±1 years, 77±1 kg), power lifters (N.=7, 24±1 years, 80±3 kg) and rock climbers (N.=8, 25±2 years, 74±2 kg) took part in a controlled forearm ischemic occlusion (5 min) assessment using near infrared spectroscopy. In addition, three fatigue protocols were completed: protocol 1, sustained maximal voluntary contraction (MVC) until exhaustion; protocol 2, sustained 40% MVC for 3 mins duration; protocol 3, an intermittent 40% MVC (5-s contraction, 5-s recovery) for a duration of 3 mins. Forearm contractile fatigue was quantified as the reduction in MVC. RESULTS MVC was equivalent between groups (P>0.05). Sustained MVC force (time to decline 50% MVC) was longer in the RC versus AT (AT: 35±5, PL: 46±6, RC: 54±4 s, P<0.05) and both AT and PL for sustained 40% MVC (AT: 56±9, RT: 62±8, RC: 87±7 s, P<0.05). Reduction in MVC was less in RC post intermittent 40% contractions (P<0.05). Oxygen desaturation half-time was longer in the RC versus AT (AT: 65±9, RT: 86±7, RC: 99±7 s, P<0.05) and this was associated with time to 50% MVC (P<0.05, r<sup>2</sup>=0.53) and time to 40% MVC task failure (P<0.05, r<sup>2</sup>=0.32). CONCLUSIONS Rock climbers' enhanced isometric fatigue-resistance and ability to maintain MVC was associated with a lower oxygen consumption of the forearm flexors during the ischemic state. This suggests a training adaptation involving intracellular oxygen consumption.
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Affiliation(s)
- Jordan Nolan
- Center for Medical and Exercise Physiology, School of Medicine, University of Wollongong, Wollongong, Australia
| | - Peter L Mclennan
- Center for Medical and Exercise Physiology, School of Medicine, University of Wollongong, Wollongong, Australia
| | - Gregory E Peoples
- Center for Medical and Exercise Physiology, School of Medicine, University of Wollongong, Wollongong, Australia -
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Keller JL, Housh TJ, Hill EC, Smith CM, Schmidt RJ, Johnson GO. Sex-Related Differences in Performance Fatigability Independent of Blood Flow Following a Sustained Muscle Action at a Low Perceptual Intensity. ACTA ACUST UNITED AC 2020. [DOI: 10.1007/s42978-020-00052-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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9
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Cè E, Longo S, Limonta E, Coratella G, Rampichini S, Esposito F. Peripheral fatigue: new mechanistic insights from recent technologies. Eur J Appl Physiol 2019; 120:17-39. [DOI: 10.1007/s00421-019-04264-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 11/12/2019] [Indexed: 12/12/2022]
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Comparison of climbing-specific strength and endurance between lead and boulder climbers. PLoS One 2019; 14:e0222529. [PMID: 31536569 PMCID: PMC6752829 DOI: 10.1371/journal.pone.0222529] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 09/01/2019] [Indexed: 11/19/2022] Open
Abstract
Albeit differences in climbing-specific strength of the forearms have been demonstrated between lead and boulder climbers, little is known about the potential differences in force and power output of the upper body pulling-apparatus between disciplines. The aim of this study was to compare the climbing-specific upper-body strength and finger flexor endurance between lead and boulder climbers, as well as to examine the relative utilization of force when testing on a ledge hold compared to a jug hold. Sixteen boulder climbers (red-point climbing grade 17.9 ± 3.3) and fifteen lead climbers (red-point climbing grade 20.5 ± 3.5) performing on an advanced level volunteered for the study. Peak force, average force and rate of force development (RFD) were measured during an isometric pull-up, average velocity in dynamic pull-up, and finger flexor endurance in an intermittent test to fatigue. The isometric pull-up was performed on a ledge hold (high finger strength requirements) and on a jug hold (very low finger strength requirements). Boulder climbers demonstrated a higher maximal and explosive strength in all strength and power measurements (26.2–52.9%, ES = 0.90–1.12, p = 0.006–0.023), whereas the finger flexor endurance test showed no significant difference between the groups (p = 0.088). Both groups were able to utilize 57–69% of peak force, average force and RFD in the ledge condition compared to the jug condition, but the relative utilization was not different between the groups (p = 0.290–0.996). In conclusion, boulder climbers were stronger and more explosive compared to lead climbers, whereas no differences in finger flexor endurance were observed. Performing climbing-specific tests on a smaller hold appears to limit the force and power output equally between the two groups.
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Muazu Musa R, Abdul Majeed A, Taha Z, Abdullah M, Husin Musawi Maliki A, Azura Kosni N. The application of Artificial Neural Network and k-Nearest Neighbour classification models in the scouting of high-performance archers from a selected fitness and motor skill performance parameters. Sci Sports 2019. [DOI: 10.1016/j.scispo.2019.02.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Bergua P, Montero-Marin J, Gomez-Bruton A, Casajús JA. Hanging ability in climbing: an approach by finger hangs on adjusted depth edges in advanced and elite sport climbers. INT J PERF ANAL SPOR 2018. [DOI: 10.1080/24748668.2018.1486115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Pedro Bergua
- Post-doctoral researcher in Sport Sciences, University of Zaragoza, Zaragoza, Spain
| | - Jesús Montero-Marin
- Primary Care Prevention and Health Promotion Research Network (RedIAPP), Zaragoza, Spain
| | - Alejandro Gomez-Bruton
- GENUD (Growth, Exercise, Nutrition and Development) Research group, Zaragoza, Spain
- Universidad Isabel I, Burgos, Spain
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición (CIBERobn)
- Instituto de Salud Carlos III, EXERNET (Exercise and health research network), Madrid, Spain
| | - José Antonio Casajús
- GENUD (Growth, Exercise, Nutrition and Development) Research group, Zaragoza, Spain
- Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición (CIBERobn)
- Instituto de Salud Carlos III, EXERNET (Exercise and health research network), Madrid, Spain
- Faculty of Health Sciences, Department of Physiatry and Nursing, University of Zaragoza, Zaragoza, Spain
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Papcke C, Krueger E, Olandoski M, Nogueira-Neto GN, Nohama P, Scheeren EM. Investigation of the Relationship Between Electrical Stimulation Frequency and Muscle Frequency Response Under Submaximal Contractions. Artif Organs 2018; 42:655-663. [PMID: 29574805 DOI: 10.1111/aor.13083] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 10/16/2017] [Accepted: 10/26/2017] [Indexed: 11/30/2022]
Abstract
Neuromuscular electrical stimulation (NMES) is a common tool that is used in clinical and laboratory experiments and can be combined with mechanomyography (MMG) for biofeedback in neuroprostheses. However, it is not clear if the electrical current applied to neuromuscular tissues influences the MMG signal in submaximal contractions. The objective of this study is to investigate whether the electrical stimulation frequency influences the mechanomyographic frequency response of the rectus femoris muscle during submaximal contractions. Thirteen male participants performed three maximal voluntary isometric contractions (MVIC) recorded in isometric conditions to determine the maximal force of knee extensors. This was followed by the application of nine modulated NMES frequencies (20, 25, 30, 35, 40, 45, 50, 75, and 100 Hz) to evoke 5% MVIC. Muscle behavior was monitored by the analysis of MMG signals, which were decomposed into frequency bands by using a Cauchy wavelet transform. For each applied electrical stimulus frequency, the mean MMG spectral/frequency response was estimated for each axis (X, Y, and Z axes) of the MMG sensor with the values of the frequency bands used as weights (weighted mean). Only with respect to the Z (perpendicular) axis of the MMG signal, the stimulus frequency of 20 Hz did not exhibit any difference with the weighted mean (P = 0.666). For the frequencies of 20 and 25 Hz, the MMG signal displayed the bands between 12 and 16 Hz in the three axes (P < 0.050). In the frequencies from 30 to 100 Hz, the muscle presented a higher concentration of the MMG signal between the 22 and 29 Hz bands for the X and Z axes, and between 16 and 34 Hz bands for the Y axis (P < 0.050 for all cases). We observed that MMG signals are not dependent on the applied NMES frequency, because their frequency contents tend to mainly remain between the 20- and 25-Hz bands. Hence, NMES does not interfere with the use of MMG in neuroprosthesis.
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Affiliation(s)
- Caluê Papcke
- Graduate Program in Health Technology, Pontifícia Universidade Católica do Paraná, Curitiba, Brazil
| | - Eddy Krueger
- Graduate Program in Rehabilitation Sciences, Anatomy Department, Universidade Estadual de Londrina, Londrina, Brazil.,Graduate Program in Biomedical Engineering, Universidade Tecnológica Federal do Paraná, Curitiba, Brazil
| | - Marcia Olandoski
- Medical School, Pontifícia Universidade Católica do Paraná, Curitiba, Brazil
| | | | - Percy Nohama
- Graduate Program in Health Technology, Pontifícia Universidade Católica do Paraná, Curitiba, Brazil
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Correlation between stiffness and electromechanical delay components during muscle contraction and relaxation before and after static stretching. J Electromyogr Kinesiol 2017; 33:83-93. [PMID: 28232285 DOI: 10.1016/j.jelekin.2017.02.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 12/23/2016] [Accepted: 02/06/2017] [Indexed: 12/22/2022] Open
Abstract
The study was aimed at assessing possible correlations of the electromechanical delay components during muscle contraction (DelayTOT) and relaxation (R-DelayTOT), with muscle-tendon unit (MTU), muscle, and tendon stiffness before and after static stretching (SS). Plantarflexor muscles' maximum voluntary torque (Tmax) was measured in 18 male participants (age 24±3yrs; body mass 76.4±8.9kg; stature 1.78±0.09m; mean±SD). During Tmax, surface electromyogram (EMG), mechanomyogram, and force signals were detected. DelayTOT and R-DelayTOT with their electrochemical and mechanical components were calculated. Passive torque and myotendinous junction displacement were assessed at 0°, 10° and 20° of dorsiflexion to determine MTU, muscle and tendon stiffness. The same protocol was repeated after SS. DelayTOT, R-DelayTOT and their mainly mechanical components correlated with MTU, muscle and tendon stiffness, both before (R2 from 0.562 to 0.894; p<0.001) and after SS (R2 from 0.726 to 0.955; p<0.001). SS decreased Tmax (-14%; p<0.001) and lengthened almost all the DelayTOT and R-DelayTOT components (from +5.9% to +30.5%; p<0.05). Correlations were found only between stiffness and the mechanical components of DelayTOT and R-DelayTOT. Correlations persisted after SS but delays increased to a higher extent than stiffness, indicating a complexity of the relationship between stiffness and delays that will be discussed in the manuscript.
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