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Giustino V, Vicari DSS, Patti A, Figlioli F, Thomas E, Schifaudo N, Tedesco M, Drid P, Paoli A, Palma A, Messina G, Bianco A. Postural control during the back squat at different load intensities in powerlifters and weightlifters. Ann Med 2024; 56:2383965. [PMID: 39078324 PMCID: PMC11290288 DOI: 10.1080/07853890.2024.2383965] [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: 12/04/2023] [Revised: 01/23/2024] [Accepted: 03/02/2024] [Indexed: 07/31/2024] Open
Abstract
BACKGROUND The movement of the barbell has been detected as success factor for the snatch and the clean and jerk events. As the barbell's movement has been shown to be related to the athlete's body movement, we hypothesized that the latter could be a success factor also for the back squat (BS) event. Hence, this study aimed to investigate postural control during the execution of the BS at different load intensities in powerlifters and weightlifters. METHODS Seventeen powerlifters and weightlifters were enrolled and the one-repetition maximum (1-RM) of the BS of each participant was measured. Afterwards, the assessment of postural control during the execution of the BS at different load intensities (i.e. 60%, 70%, 80%, 90%, 100%) of the 1-RM of each participant was carried out through a posturographic platform to measure the displacement of the centre of pressure (CoP). The following parameters were considered: sway path length (SPL), sway ellipse surface (SES), length/surface (LFS ratio), sway mean speed (SMS), CoP coordinates along X and Y planes. RESULTS We found a significant increase in SPL and LFS ratio, and a significant decrease in SMS as the load intensity increased. In detail, we detected a significant difference in: (a) SPL between the BS at 60% and 80%, 60% and 90%, 60% and 100%; between the BS at 70% and 90%, 70% and 100%; between the BS at 80% and 100%; and between the BS at 90% and 100%; (b) SMS between the BS at 60% and 80%, 60% and 90%; (c) LFS ratio between the BS at 60% and 90%, 60% and 100%. CONCLUSIONS These results suggest that powerlifters and weightlifters adopt different postural control strategies depending on the load intensity when performing the BS. Our findings showed that higher effort could affect postural control during the BS. Thus, postural control could be considered a success factor for the BS.
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Affiliation(s)
- Valerio Giustino
- Sport and Exercise Sciences Research Unit, Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy
| | - Domenico Savio Salvatore Vicari
- Sport and Exercise Sciences Research Unit, Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Antonino Patti
- Sport and Exercise Sciences Research Unit, Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy
| | - Flavia Figlioli
- Sport and Exercise Sciences Research Unit, Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy
- PhD Program in Health Promotion and Cognitive Sciences, University of Palermo, Palermo, Italy
| | - Ewan Thomas
- Sport and Exercise Sciences Research Unit, Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy
| | - Naima Schifaudo
- Sport and Exercise Sciences Research Unit, Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy
| | | | - Patrik Drid
- Faculty of Sport and Physical Education, University of Novi Sad, Novi Sad, Serbia
| | - Antonio Paoli
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Antonio Palma
- Sport and Exercise Sciences Research Unit, Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy
- Regional Sports School, Italian National Olympic Committee (CONI) Sicilia, Palermo, Italy
| | - Giuseppe Messina
- Department of Human Sciences and Promotion of the Quality of Life, San Raffaele University, Rome, Italy
| | - Antonino Bianco
- Sport and Exercise Sciences Research Unit, Department of Psychology, Educational Science and Human Movement, University of Palermo, Palermo, Italy
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Cornejo-Daza PJ, Sánchez-Valdepeñas J, Páez-Maldonado J, Rodiles-Guerrero L, Boullosa D, León-Prados JA, Wernbom M, Pareja-Blanco F. Acute Responses to Traditional and Cluster-Set Squat Training With and Without Blood Flow Restriction. J Strength Cond Res 2024; 38:1401-1412. [PMID: 38780903 PMCID: PMC11286160 DOI: 10.1519/jsc.0000000000004820] [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: 05/25/2024]
Abstract
ABSTRACT Cornejo-Daza, PJ, Sánchez-Valdepeñas, J, Páez-Maldonado, J, Rodiles-Guerrero, L, Boullosa, D, León-Prados, JA, Wernbom, M, and Pareja-Blanco, F. Acute responses to traditional and cluster-set squat training with and without blood flow restriction. J Strength Cond Res 38(8): 1401-1412, 2024-To compare the acute responses to different set configurations (cluster [CLU] vs. traditional [TRA]) under distinct blood flow conditions (free vs. restricted) in full-squat (SQ). Twenty resistance-trained males performed 4 protocols that differed in the set configuration (TRA: continuous repetitions; vs. CLU: 30 seconds of rest every 2 repetitions) and in the blood flow condition (FF: free-flow; vs. blood flow restriction [BFR]: 50% of arterial occlusion pressure). The relative intensity (60% 1RM), volume (3 sets of 8 repetitions), and resting time (2 minutes) were equated. Mean propulsive force (MPF), velocity (MPV) and power (MPP), and electromyography (EMG) parameters were recorded during each repetition. Tensiomyography (TMG), blood lactate, countermovement jump (CMJ) height, maximal voluntary isometric contraction, in SQ, and movement velocity against the load that elicited a 1 m·s -1 velocity at baseline (V1-load) in SQ were assessed at pre- and post-exercise. The CLU protocols allowed a better maintenance of MPF, MPV, MPP, and EMG median frequency during the exercise compared to TRA (clu-time interaction, p < 0.05). The TRA protocols experienced greater impairments post-exercise in TMG- and EMG-derived variables (clu-time interaction, p < 0.05) and SQ and CMJ performance (clu-time interaction, p = 0.08 and p < 0.05, respectively), as well as higher blood lactate concentrations (clu-time interaction, p < 0.001) than CLU. Moreover, BFR displayed decreases in TMG variables (bfr-time interaction, p < 0.01), but BFR-CLU resulted in the greatest reduction in twitch contraction time ( p < 0.001). Cluster sets reduced fatigue during and after the training session and BFR exacerbated impairments in muscle mechanical properties; however, the combination of both could improve contraction speed after exercise.
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Affiliation(s)
- Pedro J. Cornejo-Daza
- Science Based Training Research Group. Department of Sports and Computers Sciences. Universidad Pablo de Olavide, Seville, Spain
- Faculty of Sport Sciences, Department of Sports and Computers Sciences, Universidad Pablo de Olavide, Seville, Spain
- Department of Human Motor and Sports Performance, University of Seville, Seville, Spain
| | - Juan Sánchez-Valdepeñas
- Science Based Training Research Group. Department of Sports and Computers Sciences. Universidad Pablo de Olavide, Seville, Spain
- Faculty of Sport Sciences, Department of Sports and Computers Sciences, Universidad Pablo de Olavide, Seville, Spain
| | - Jose Páez-Maldonado
- Science Based Training Research Group. Department of Sports and Computers Sciences. Universidad Pablo de Olavide, Seville, Spain
- Faculty of Sport Sciences, University of Seville, Osuna, Spain
| | - Luis Rodiles-Guerrero
- Science Based Training Research Group. Department of Sports and Computers Sciences. Universidad Pablo de Olavide, Seville, Spain
- Department of Human Motor and Sports Performance, University of Seville, Seville, Spain
| | - Daniel Boullosa
- Faculty of Physical Activity and Sports Sciences, Universidad de León, León, Spain
- Integrated Institute of Health, Federal University of Mato Grosso do Sul, Campo Grande, Brazil
- College of Healthcare Sciences, James Cook University, Townsville, Australia; and
| | - Juan A. León-Prados
- Science Based Training Research Group. Department of Sports and Computers Sciences. Universidad Pablo de Olavide, Seville, Spain
- Faculty of Sport Sciences, Department of Sports and Computers Sciences, Universidad Pablo de Olavide, Seville, Spain
| | - Mathias Wernbom
- Integrated Institute of Health, Federal University of Mato Grosso do Sul, Campo Grande, Brazil
| | - Fernando Pareja-Blanco
- Science Based Training Research Group. Department of Sports and Computers Sciences. Universidad Pablo de Olavide, Seville, Spain
- Faculty of Sport Sciences, Department of Sports and Computers Sciences, Universidad Pablo de Olavide, Seville, Spain
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Cabral HV, Inglis JG, Cudicio A, Cogliati M, Orizio C, Yavuz US, Negro F. Muscle contractile properties directly influence shared synaptic inputs to spinal motor neurons. J Physiol 2024; 602:2855-2872. [PMID: 38709959 DOI: 10.1113/jp286078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 04/18/2024] [Indexed: 05/08/2024] Open
Abstract
Alpha band oscillations in shared synaptic inputs to the alpha motor neuron pool can be considered an involuntary source of noise that hinders precise voluntary force production. This study investigated the impact of changing muscle length on the shared synaptic oscillations to spinal motor neurons, particularly in the physiological tremor band. Fourteen healthy individuals performed low-level dorsiflexion contractions at ankle joint angles of 90° and 130°, while high-density surface electromyography (HDsEMG) was recorded from the tibialis anterior (TA). We decomposed the HDsEMG into motor units spike trains and calculated the motor units' coherence within the delta (1-5 Hz), alpha (5-15 Hz), and beta (15-35 Hz) bands. Additionally, force steadiness and force spectral power within the tremor band were quantified. Results showed no significant differences in force steadiness between 90° and 130°. In contrast, alpha band oscillations in both synaptic inputs and force output decreased as the length of the TA was moved from shorter (90°) to longer (130°), with no changes in delta and beta bands. In a second set of experiments (10 participants), evoked twitches were recorded with the ankle joint at 90° and 130°, revealing longer twitch durations in the longer TA muscle length condition compared to the shorter. These experimental results, supported by a simple computational simulation, suggest that increasing muscle length enhances the muscle's low-pass filtering properties, influencing the oscillations generated by the Ia afferent feedback loop. Therefore, this study provides valuable insights into the interplay between muscle biomechanics and neural oscillations. KEY POINTS: We investigated whether changes in muscle length, achieved by changing joint position, could influence common synaptic oscillations to spinal motor neurons, particularly in the tremor band (5-15 Hz). Our results demonstrate that changing muscle length from shorter to longer induces reductions in the magnitude of alpha band oscillations in common synaptic inputs. Importantly, these reductions were reflected in the oscillations of muscle force output within the alpha band. Longer twitch durations were observed in the longer muscle length condition compared to the shorter, suggesting that increasing muscle length enhances the muscle's low-pass filtering properties. Changes in the peripheral contractile properties of motor units due to changes in muscle length significantly influence the transmission of shared synaptic inputs into muscle force output. These findings prove the interplay between muscle mechanics and neural adaptations.
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Affiliation(s)
- Hélio V Cabral
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia, Italy
| | - J Greig Inglis
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia, Italy
| | - Alessandro Cudicio
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia, Italy
| | - Marta Cogliati
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia, Italy
| | - Claudio Orizio
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia, Italy
| | - Utku S Yavuz
- Biomedical Signals and Systems, University of Twente, Enschede, Netherlands
| | - Francesco Negro
- Department of Clinical and Experimental Sciences, Università degli Studi di Brescia, Brescia, Italy
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Yuan R, Peng Y, Ji R, Zheng Y. Comparison of the activation level in the sensorimotor cortex between motor point and proximal nerve bundle electrical stimulation. J Neural Eng 2024; 21:026029. [PMID: 38537271 DOI: 10.1088/1741-2552/ad3850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 03/27/2024] [Indexed: 04/06/2024]
Abstract
Objective.Neuromuscular electrical stimulation (NMES) is widely used for motor function rehabilitation in stroke survivors. Compared with the conventional motor point (MP) stimulation, the stimulation at the proximal segment of the peripheral nerve (PN) bundles has been demonstrated to have multiple advantages. However, it is not known yet whether the PN stimulation can increase the cortical activation level, which is crucial for motor function rehabilitation.Approach.The current stimuli were delivered transcutaneously at the muscle belly of the finger flexors and the proximal segment of the median and ulnar nerves, respectively for the MP and PN stimulation. The stimulation intensity was determined to elicit the same contraction levels between the two stimulation methods in 18 healthy individuals and a stroke patient. The functional near-infrared spectroscopy and the electromyogram were recorded to compare the activation pattern of the sensorimotor regions and the target muscles.Main Results.For the healthy subjects, the PN stimulation induced significantly increased concentration of the oxygenated hemoglobin in the contralateral sensorimotor areas, and enhanced the functional connectivity between brain regions compared with the MP stimulation. Meanwhile, the compound action potentials had a smaller amplitude and the H-reflex became stronger under the PN stimulation, indicating that more sensory axons were activated in the PN stimulation. For the stroke patient, the PN stimulation can elicit finger forces and induce activation of both the contralateral and ipsilateral motor cortex.Conclusions. Compared with the MP stimulation, the PN stimulation can induce more cortical activation in the contralateral sensorimotor areas possibly via involving more activities in the central pathway.Significance.This study demonstrated the potential of the PN stimulation to facilitate functional recovery via increasing the cortical activation level, which may help to improve the outcome of the NMES-based rehabilitation for motor function recovery after stroke.
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Affiliation(s)
- Rui Yuan
- Institute of Engineering and Medicine Interdisciplinary Studies and the State Key Laboratory for Manufacturing Systems Engineering, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Yu Peng
- Department of Rehabilitation, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Run Ji
- National Research Center for Rehabilitation Technical Aids and the Key Laboratory of Human Motion Analysis and Rehabilitation Technology of the Ministry of Civil Affairs, Beijing, People's Republic of China
| | - Yang Zheng
- Institute of Engineering and Medicine Interdisciplinary Studies and the State Key Laboratory for Manufacturing Systems Engineering, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an, People's Republic of China
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Jacquet T, Poulin-Charronnat B, Bard P, Lepers R. Effect of mental fatigue on hand force production capacities. PLoS One 2024; 19:e0298958. [PMID: 38564497 PMCID: PMC10986955 DOI: 10.1371/journal.pone.0298958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 02/01/2024] [Indexed: 04/04/2024] Open
Abstract
Mental fatigue is common in society, but its effects on force production capacities remain unclear. This study aimed to investigate the impact of mental fatigue on maximal force production, rate of force development-scaling factor (RFD-SF), and force steadiness during handgrip contractions. Fourteen participants performed two randomized sessions, during which they either carried out a cognitively demanding task (i.e., a visual attention task) or a cognitively nondemanding task (i.e., documentary watching for 62 min). The mental fatigue was evaluated subjectively and objectively (performances and electroencephalography). Maximal voluntary contraction (MVC) force, RFD-SF, and force steadiness (i.e., force coefficient of variation at submaximal intensities; 25, 50, and 75% of MVC) were recorded before and after both tasks. The feeling of mental fatigue was much higher after completing the cognitively demanding task than after documentary watching (p < .001). During the cognitively demanding task, mental fatigue was evidenced by increased errors, missed trials, and decreased N100 amplitude over time. While no effect was reported on force steadiness, both tasks induced a decrease in MVC (p = .040), a force RFD-SF lower slope (p = .011), and a reduction in the coefficient of determination (p = .011). Nevertheless, these effects were not explicitly linked to mental fatigue since they appeared both after the mentally fatiguing task and after watching the documentary. The study highlights the importance of considering cognitive engagement and mental load when optimizing motor performance to mitigate adverse effects and improve force production capacities.
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Affiliation(s)
- Thomas Jacquet
- Faculté des Sciences du Sport, CAPS, Inserm U1093, BP 27877 UFR STAPS, Université de Bourgogne, Dijon, France
| | | | - Patrick Bard
- LEAD – CNRS UMR5022, Université de Bourgogne, Dijon, France
| | - Romuald Lepers
- Faculté des Sciences du Sport, CAPS, Inserm U1093, BP 27877 UFR STAPS, Université de Bourgogne, Dijon, France
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Vieira TM, Cerone GL, Bruno M, Bachero-Mena B. Myoelectric manifestations of fatigue of the finger flexor muscles and endurance capacity in experienced versus intermediate climbers during suspension tasks. J Sports Sci 2024; 42:655-664. [PMID: 38794799 DOI: 10.1080/02640414.2024.2357470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 05/13/2024] [Indexed: 05/26/2024]
Abstract
Climbing is a physically demanding discipline, placing significant loads on the finger flexors. Notwithstanding the documented greater endurance capacity of experienced climbers, the mechanisms explaining these training-induced adaptations remain unknown. We therefore investigate whether two non-competing strategies - muscle adaptation and alternate muscle recruitment - may explain the disparity in endurance capacity in participants with different climbing experience. We analysed high-density surface electromyograms (EMGs) from 38 Advanced and Intermediate climbers, during suspension exercises over three different depths (15, 20, 30 mm) using a half-crimp grip position. From the spatial distribution of changes in MeDian Frequency and Root Mean Square values until failure, we assessed how much and how diffusely the myoelectric manifestations of fatigue took place. Advanced climbers exhibited greater endurance, as evidenced by significantly longer failure time (p < 0.009) and lower changes in MDF values (p < 0.013) for the three grip depths. These changes were confined to a small skin region (nearly 25% of the grid size), centred at variable locations across participants. Moreover, lower MDF changes were significantly associated with longer suspension times. Collectively, our results suggest that muscle adaptation rather than load sharing between and within muscles is more likely to explain the improved endurance in experienced climbers.
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Affiliation(s)
- Taian Martins Vieira
- Laboratory for Engineering of the Neuromuscular System, Department of Electronics and Telecommunications, Politecnico di Torino, Turin, Italy
- PoliToBIOMed Lab, Politecnico di Torino, Torino, Italy
| | - Giacinto Luigi Cerone
- Laboratory for Engineering of the Neuromuscular System, Department of Electronics and Telecommunications, Politecnico di Torino, Turin, Italy
- PoliToBIOMed Lab, Politecnico di Torino, Torino, Italy
| | - Martina Bruno
- Laboratory for Engineering of the Neuromuscular System, Department of Electronics and Telecommunications, Politecnico di Torino, Turin, Italy
| | - Beatriz Bachero-Mena
- Department of Human Movement and Sport Performance, University of Seville, Seville, Spain
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García-Arrabé M, de la Plaza San Frutos M, Bermejo-Franco A, del Prado-Álvarez R, López-Ruiz J, del-Blanco-Muñiz JA, Giménez MJ. Effects of Minimalist vs. Traditional Running Shoes on Abdominal Lumbopelvic Muscle Activity in Women Running at Different Speeds: A Randomized Cross-Over Clinical Trial. SENSORS (BASEL, SWITZERLAND) 2024; 24:310. [PMID: 38257403 PMCID: PMC10818597 DOI: 10.3390/s24020310] [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: 11/23/2023] [Revised: 12/20/2023] [Accepted: 01/03/2024] [Indexed: 01/24/2024]
Abstract
This study aimed to investigate if the characteristics of different running shoes could influence intra-abdominal pressure during running. A single-centre, randomized, prospective cross-over clinical trial was performed measuring activity patterns of internal oblique (IO), lumbar erector (LE), and gluteus maximus (GM) muscles in healthy women when running with minimalist shoes (MS). Participants were randomly allocated into two-sequence (MS/TS or TS/MS) treadmill running at six, nine, and eleven km/h. The surface electromyographic activity of IO, LE, and GM muscles were recorded while running. A repeated measures ANOVA explored the interaction effects of three-muscle x three speeds x two shoes. Significance was set at p ≤ 0.05. Fifty-one healthy nulliparous women (mean age: 26.55 ± 5.11 years; body mass index: 21.29 ± 2.07 Kg/m2) were included. Our findings revealed lower activations of the LE compared to the internal oblique IO and GM, irrespective of running speed and footwear used. Electromyographic activation significantly increased with higher running speeds (p < 0.001) for all muscles, regardless of the type of footwear. Although electromyographic records with MS consistently showed higher values than those with TS, the differences were not statistically significant for all muscles at all speeds. Our results indicate that electromyographic activation patterns vary according to the muscle group, exhibiting higher values with increased running speed. No significant differences were observed between MS and TS.
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Affiliation(s)
- María García-Arrabé
- Faculty of Sport Sciences, Universidad Europea de Madrid, Tajo s/n, 28670 Villaviciosa de Odón, Spain; (M.G.-A.); (M.d.l.P.S.F.); (A.B.-F.); (R.d.P.-Á.); (J.L.-R.); (J.A.d.-B.-M.)
- Department of Radiology, Rehabilitation and Physiotherapy, Complutense University of Madrid, Avda. Complutense s/n, 28040 Madrid, Spain
| | - Marta de la Plaza San Frutos
- Faculty of Sport Sciences, Universidad Europea de Madrid, Tajo s/n, 28670 Villaviciosa de Odón, Spain; (M.G.-A.); (M.d.l.P.S.F.); (A.B.-F.); (R.d.P.-Á.); (J.L.-R.); (J.A.d.-B.-M.)
| | - Alberto Bermejo-Franco
- Faculty of Sport Sciences, Universidad Europea de Madrid, Tajo s/n, 28670 Villaviciosa de Odón, Spain; (M.G.-A.); (M.d.l.P.S.F.); (A.B.-F.); (R.d.P.-Á.); (J.L.-R.); (J.A.d.-B.-M.)
| | - Rebeca del Prado-Álvarez
- Faculty of Sport Sciences, Universidad Europea de Madrid, Tajo s/n, 28670 Villaviciosa de Odón, Spain; (M.G.-A.); (M.d.l.P.S.F.); (A.B.-F.); (R.d.P.-Á.); (J.L.-R.); (J.A.d.-B.-M.)
| | - Javier López-Ruiz
- Faculty of Sport Sciences, Universidad Europea de Madrid, Tajo s/n, 28670 Villaviciosa de Odón, Spain; (M.G.-A.); (M.d.l.P.S.F.); (A.B.-F.); (R.d.P.-Á.); (J.L.-R.); (J.A.d.-B.-M.)
| | - José Angel del-Blanco-Muñiz
- Faculty of Sport Sciences, Universidad Europea de Madrid, Tajo s/n, 28670 Villaviciosa de Odón, Spain; (M.G.-A.); (M.d.l.P.S.F.); (A.B.-F.); (R.d.P.-Á.); (J.L.-R.); (J.A.d.-B.-M.)
| | - María-José Giménez
- Faculty of Sport Sciences, Universidad Europea de Madrid, Tajo s/n, 28670 Villaviciosa de Odón, Spain; (M.G.-A.); (M.d.l.P.S.F.); (A.B.-F.); (R.d.P.-Á.); (J.L.-R.); (J.A.d.-B.-M.)
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Ogawa A, Sakamoto M, Matsumoto A, Okusaki T, Sasaya R, Irie K, Liang N. Accuracy of Force Generation and Preparatory Prefrontal Oxygenation in Ballistic Hand Power and Precision Grips. J Mot Behav 2023; 56:226-240. [PMID: 37997191 DOI: 10.1080/00222895.2023.2283541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 11/03/2023] [Indexed: 11/25/2023]
Abstract
It remains unclear whether accurate motor performance and cortical activation differ among grasping forms across several force levels. In the present study, a ballistic target force matching task (20%, 40%, 60%, and 80% of maximum voluntary force) with power grip, side pinch, and pulp pinch was utilized to explore the accuracy of the forces generated as well as the muscular activity of intrinsic and extrinsic hand muscles. By using near-infrared spectroscopy, we also examined bilateral dorsolateral prefrontal cortex (DLPFC) activation during the preparatory phase (initial 10 s) of the task. The accuracy of the power grip and pulp pinch was relatively higher than that of the side pinch, and the electromyographic activity of intrinsic hand muscles exhibited a similar trend for power grip and side pinch, while the opposite muscle recruitment pattern was observed for pulp pinch. The increment of DLPFC oxygenation across force levels differed among grasping forms, with greater activity at relatively higher levels in the power grip and side pinch, and at relatively lower levels in the pulp pinch. Taken together, the differential contribution of the DLPFC may be responsible for force generation depending on different grasping forms and force levels.
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Affiliation(s)
- Akari Ogawa
- Cognitive Motor Neuroscience, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Mizuki Sakamoto
- Cognitive Motor Neuroscience, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Amiri Matsumoto
- Cognitive Motor Neuroscience, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Tetsuei Okusaki
- Cognitive Motor Neuroscience, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Ren Sasaya
- Cognitive Motor Neuroscience, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Keisuke Irie
- Cognitive Motor Neuroscience, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Nan Liang
- Cognitive Motor Neuroscience, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, Japan
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Benitez B, Dinyer-McNeely TK, McCallum L, Kwak M, Succi PJ, Bergstrom HC. Electromyographic and mechanomyographic responses of the biceps brachii during concentric and eccentric muscle actions to failure at high and low relative loads. Eur J Appl Physiol 2023; 123:2145-2156. [PMID: 37219738 DOI: 10.1007/s00421-023-05199-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 04/06/2023] [Indexed: 05/24/2023]
Abstract
PURPOSE This study examined neuromuscular responses of the biceps brachii (BB) for concentric and eccentric muscle actions during bilateral, dynamic constant external resistance (DCER), reciprocal forearm flexions and extensions to failure at high (80% 1 repetition maximum [1RM]) and low (30% 1RM) relative loads. METHODS Nine women completed 1RM testing and repetitions to failure (RTF) at 30 and 80% 1RM. Electromyographic (EMG) and mechanomyographic (MMG) amplitude (AMP) and mean power frequency (MPF) signals were measured from the BB. Analyses included repeated measures ANOVAs (p < 0.05) and post-hoc pairwise comparisons with Bonferroni corrected alpha of p < 0.008 and p < 0.01 for between and within factor pairwise comparisons, respectively. RESULTS EMG AMP and MPF were significantly greater for concentric than eccentric muscle actions, regardless of load or time. However, time course of change analysis revealed parallel increases in EMG AMP for concentric and eccentric muscle actions during the RTF trials at 30% 1RM, but no change at 80% 1RM. There were significant increases in MMG AMP during concentric muscle actions, but decreases or no change during eccentric muscle actions. EMG and MMG MPF decreased over time, regardless of muscle action type and loading condition. CONCLUSION The greater EMG AMP and MPF values during concentric compared to eccentric muscle actions may reflect the difference in the efficiency characteristic of these muscle actions. The neuromuscular responses suggested that fatigue may be mediated by recruitment of additional motor units with lower firing rates during concentric muscle actions, and changes in motor unit synchronization during eccentric muscle actions.
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Affiliation(s)
- Brian Benitez
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY, USA.
| | - Taylor K Dinyer-McNeely
- School of Kinesiology, Applied Health and Recreation, Oklahoma State University, Stillwater, OK, USA
| | - Lindsay McCallum
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY, USA
| | - Minyoung Kwak
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY, USA
| | - Pasquale J Succi
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY, USA
| | - Haley C Bergstrom
- Department of Kinesiology and Health Promotion, University of Kentucky, Lexington, KY, USA
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10
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VanHaitsma TA, Gonzalez SP, Kajitani S, Gabriano E, Hoiosen GE, Oldach MC, Kingsley KL. Three weeks of mental training changes physiological outcomes during a time trial to exhaustion. Eur J Appl Physiol 2023; 123:1977-1989. [PMID: 37129629 PMCID: PMC10460752 DOI: 10.1007/s00421-023-05206-3] [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: 06/06/2022] [Accepted: 04/17/2023] [Indexed: 05/03/2023]
Abstract
Mental training (MT) can increase endurance performance. The purpose of this study was to examine the minimum dose of mental training needed to increase performance and elucidate the physiological mechanisms underlying this improvement. In a randomized between groups pre-test-post-test design, 33 participants visited the lab on 6 separate days. A VO2peak with ventilatory threshold (VT) was performed on day 1. The subsequent visits consisted of time trials to exhaustion (TTE) performed at 10% above VT. Between visit 3 and 6, the MT group (n = 16) watched a video for 10-15 min each day for 3 weeks, while the control group (CON; n = 17) did no mental training. Heart rate (HR), rate of perceived exertion (RPE), VAS scores for pain and fatigue, electromyography, and metabolic and neuromuscular data were collected and recorded during the time trials. The GRIT-S and CD-RISC 10 surveys were completed before study days 3 and 6. TTE increased significantly for MT beginning after 2 weeks (10.0 ± 13.1%) with no further change after 3 weeks (10.4 ± 13.2). TTE also significantly decreased during the last TTE for CON (-10.3 ± 12.7). VO2, ventilation, and frequency of breathing were significantly reduced in the latter stages of the TTE for MT. EMG was also significantly decreased for MT as compared for CON throughout the trial. Three weeks of mental training improves performance by reducing EMG, decreasing activation of the muscle and reducing metabolic factors during the latter stages of exercise.
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Affiliation(s)
| | - Stephen P Gonzalez
- Department of Kinesiology, Sport Studies, and Physical Education, Dartmouth College, Hanover, NH, USA
| | - Sten Kajitani
- Department of Kinesiology, Westmont College, Santa Barbara, CA, USA
| | - Emma Gabriano
- Department of Kinesiology, Westmont College, Santa Barbara, CA, USA
| | - Gavin E Hoiosen
- Department of Kinesiology, Westmont College, Santa Barbara, CA, USA
| | - Michael C Oldach
- Department of Kinesiology, Westmont College, Santa Barbara, CA, USA
| | - Karly L Kingsley
- Department of Kinesiology, Westmont College, Santa Barbara, CA, USA
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11
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Raikova R, Krutki P, Celichowski J. Skeletal muscle models composed of motor units: A review. J Electromyogr Kinesiol 2023; 70:102774. [PMID: 37099899 DOI: 10.1016/j.jelekin.2023.102774] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 04/06/2023] [Accepted: 04/09/2023] [Indexed: 04/28/2023] Open
Abstract
The mathematical muscle models should include several aspects of muscle structure and physiology. First, muscle force is the sum of forces of multiple motor units (MUs), which have different contractile properties and play different roles in generating muscle force. Second, whole muscle activity is an effect of net excitatory inputs to a pool of motoneurons innervating the muscle, which have different excitability, influencing MU recruitment. In this review, we compare various methods for modeling MU twitch and tetanic forces and then discuss muscle models composed of different MU types and number. We first present four different analytical functions used for twitch modeling and show limitations related to the number of twitch describing parameters. We also show that a nonlinear summation of twitches should be considered in modeling tetanic contractions. We then compare different muscle models, most of which are variations of Fuglevand's model, adopting a common drive hypothesis and the size principle. We pay attention to integrating previously developed models into a consensus model based on physiological data from in vivo experiments on the rat medial gastrocnemius muscle and its respective motoneurons. Finally, we discuss the shortcomings of existing models and potential applications for studying MU synchronization, potentiation, and fatigue.
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Affiliation(s)
- Rositsa Raikova
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Bulgaria.
| | - Piotr Krutki
- Department of Neurobiology, Poznan University of Physical Education, Poland
| | - Jan Celichowski
- Department of Neurobiology, Poznan University of Physical Education, Poland
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12
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Liu XJ, Ge S, Cordova A, Yaghi Z, Jiang BY, Yue GH, Yao WX. Elderly may benefit more from motor imagery training in gaining muscle strength than young adults: A systematic review and meta-analysis. Front Psychol 2023; 13:1052826. [PMID: 36687842 PMCID: PMC9845905 DOI: 10.3389/fpsyg.2022.1052826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 12/05/2022] [Indexed: 01/05/2023] Open
Abstract
Objective The current review was aimed to determine the effectiveness of mental imagery training (MIT) on the enhancement of maximum voluntary muscle contraction (MVC) force for healthy young and old adults. Data sources Six electronic databases were searched from July 2021 to March 2022. Search terms included: "motor imagery training," "motor imagery practice," "mental practice," "mental training," "movement imagery," "cognitive training," "strength," "force," "muscle strength," "performance," "enhancement," "improvement," "development," and "healthy adults." Study selection and data extraction Randomized controlled trials of MIT in enhancing muscle strength with healthy adults were selected. The decision on whether a study met the inclusion criteria of the review was made by two reviewers independently. Any disagreements between the two reviewers were first resolved by discussion between the two reviewers. If consensus could not be reached, then it would be arbitrated by a third reviewer. Data synthesis Twenty-five studies including both internal MIT and external MIT were included in meta-analysis for determining the efficacy of MIT on enhancing muscle strength and 22 internal MIT were used for subgroup analysis for examining dose-response relationship of MIT on MVC. Results MIT demonstrated significant benefit on enhancing muscle strength when compared with no exercise, Effect Size (ES), 1.10, 95% confidence interval (CI), 0.89-1.30, favoring MIT, but was inferior to physical training (PT), ES, 0.38, 95% CI, 0.15-0.62, favoring PT. Subgroup analysis demonstrated that MIT was more effective for older adults (ES, 2.17, 95% CI, 1.57-2.76) than young adults (ES, 0.95, 95% CI, 0.74-1.17), p = 0.0002, and for small finger muscles (ES, 1.64, 95% CI, 1.06-2.22) than large upper extremity muscles (ES, 0.86, 95% CI, 0.56-1.16), p = 0.02. No significant difference was found in the comparison of small finger muscles and large lower extremity muscles, p = 0.19 although the ES of the former (ES, 1.64, 95% CI, 1.06-2.22) was greater than that of the later (ES, 1.20, 95%, 0.88-1.52). Conclusion This review demonstrates that MIT has better estimated effects on enhancing MVC force compared to no exercise, but is inferior to PT. The combination of MIT and PT is equivalent to PT alone in enhancing muscle strength. The subgroup group analysis further suggests that older adults and small finger muscles may benefit more from MIT than young adults and larger muscles.
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Affiliation(s)
- Xiao J. Liu
- College of Art, Beijing Sport University, Beijing, China
| | - Sha Ge
- College of Sports Science, Tianjin Normal University, Tianjin, China
| | - Alberto Cordova
- Department of Kinesiology, College for Health, Community, and Policy, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Zayd Yaghi
- Department of Kinesiology, College for Health, Community, and Policy, The University of Texas at San Antonio, San Antonio, TX, United States
| | - Bo Y. Jiang
- School of Public Health, Jilin Medical University, Jilin, China
| | - Guang H. Yue
- Center for Mobility and Rehabilitation Engineering Research, Kessler Foundation, West Orange, NJ, United States
- Rutgers New Jersey Medical School, Rutgers, The State University of New Jersey, New Brunswick, NJ, United States
| | - Wan X. Yao
- Department of Kinesiology, College for Health, Community, and Policy, The University of Texas at San Antonio, San Antonio, TX, United States
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García-Arrabe M, García-Fernández P, Ruiz-Ruiz B, del Prado-Álvarez R, Romero-Morales C, Díaz-Arribas MJ. Effects of minimalist shoes on pelvic floor activity in nulliparous women during running at different velocities: a randomized cross-over clinical trial. Sci Rep 2022; 12:21218. [PMID: 36481768 PMCID: PMC9732344 DOI: 10.1038/s41598-022-25344-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 11/29/2022] [Indexed: 12/13/2022] Open
Abstract
In the last decade, minimalist shoes have gained popularity as an alternative to traditional shoes. The aim of the present study was to determine the short-term effects of minimalist shoes in femur range of motion (ROM) and cadence. The secondary objectives were the assessment of the electromyographic activity of the pelvic floor muscles (PFM) in nulliparous women. A randomized, prospective cross-over clinical trial design was used for the study. A total of 51 participants were randomly allocated into a two-sequence crossover design (AB/BA crossover design). Femur ROM, cadence and PFM activity were recorded. The femur ROM at 6 km/h was greater with the minimalist shoes by 1.62 degrees than with the traditional ones (p = 0.001). There was a main effect of the type of shoe (p = 0.015) systematically observing a higher running cadence with the minimalist shoe compared to the traditional one. Electromyographic activity of the PFM revealed significant differences for 11 km/h for the total average (p = 0.027) and the minimum peaks at 9 km/h (p = 0.011) and 11 km/h (p = 0.048) for the minimalist shoe with respect to the traditional shoes. Minimalist shoes produce immediate effects on the biomechanical variables of running. An increase was observed in the femur ROM at 6 km/h and in the cadence at 11 km/h with the use of minimalist shoes. The use of minimalist shoes increased the electromyographic activation of the PFM in the minimum peaks at speeds of 9 and 11 km/h and in the total average at speeds of 11 km/h compared to the traditional shoe.
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Affiliation(s)
- María García-Arrabe
- grid.119375.80000000121738416Faculty of Sport Sciences, Universidad Europea de Madrid, Calle Tajo s/n, 28670 Villaviciosa de Odón, Madrid, Spain
| | - Pablo García-Fernández
- grid.4795.f0000 0001 2157 7667Department of Radiology, Rehabilitation and Physiotherapy, Faculty of Nursing, Complutense University of Madrid, Plaza Ramón y Cajal nº 3, Ciudad Universitaria, 28040 Madrid, Spain
| | - Beatriz Ruiz-Ruiz
- grid.119375.80000000121738416Faculty of Sport Sciences, Universidad Europea de Madrid, Calle Tajo s/n, 28670 Villaviciosa de Odón, Madrid, Spain
| | - Rebeca del Prado-Álvarez
- grid.119375.80000000121738416Faculty of Sport Sciences, Universidad Europea de Madrid, Calle Tajo s/n, 28670 Villaviciosa de Odón, Madrid, Spain
| | - Carlos Romero-Morales
- grid.119375.80000000121738416Faculty of Sport Sciences, Universidad Europea de Madrid, Calle Tajo s/n, 28670 Villaviciosa de Odón, Madrid, Spain
| | - María José Díaz-Arribas
- grid.4795.f0000 0001 2157 7667Department of Radiology, Rehabilitation and Physiotherapy, Faculty of Nursing, Complutense University of Madrid, Plaza Ramón y Cajal nº 3, Ciudad Universitaria, 28040 Madrid, Spain
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14
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Bunno Y, Onigata C. Influence of emotion on precision grip force control: A comparison of pleasant and neutral emotion. Front Psychol 2022; 13:1038522. [DOI: 10.3389/fpsyg.2022.1038522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/21/2022] [Indexed: 12/03/2022] Open
Abstract
ObjectiveThe present study aimed to investigate the impact of emotion on force steadiness of isometric precision pinch grip that is not direction-specific.MethodsThirty-two healthy volunteer subjects participated in the present study. Subjects were divided into two experimental groups: pleasant image group and neutral image group. The isometric precision pinch grip task was performed for three times. Specifically, the first task was performed before pleasant or neutral picture viewing, the second task was performed immediately after picture viewing, further the third task was performed 30 seconds after the second task. During the isometric precision pinch grip task, participants were asked to exert pinch grip force at 10% of maximal voluntary contraction with visual feedback. The coefficient of variation of force production and normalized root mean square value of electromyography activity were calculated.ResultsAfter pleasant picture viewing, coefficient of variation of pinch force production and normalized root mean square value of electromyography was decreased. While, in the neutral image condition, theses variables were not altered. More important, compared to the neutral image condition, pleasant emotion led to lower coefficient of variation of pinch grip force production.ConclusionThese findings indicate that pleasant emotion improves force control of isometric precision pinch grip. Therefore, in clinical settings, the emotional state of patients may affect the effectiveness of rehabilitation and should be taken into consideration.
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15
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Cardoso de Oliveira M, Naville Watanabe R, Kohn AF. Electrophysiological and functional signs of Guillain-Barré syndrome predicted by a multiscale neuromuscular computational model. J Neural Eng 2022; 19. [DOI: 10.1088/1741-2552/ac91f8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 09/14/2022] [Indexed: 11/11/2022]
Abstract
Abstract
Objective. The diagnosis of nerve disorders in humans has relied heavily on the measurement of electrical signals from nerves or muscles in response to electrical stimuli applied at appropriate locations on the body surface. The present study investigated the demyelinating subtype of Guillain-Barré syndrome using multiscale computational model simulations to verify how demyelination of peripheral axons may affect plantar flexion torque as well as the ongoing electromyogram (EMG) during voluntary isometric or isotonic contractions. Approach. Changes in axonal conduction velocities, mimicking those found in patients with the disease at different stages, were imposed on a multiscale computational neuromusculoskeletal model to simulate subjects performing unipodal plantar flexion force and position tasks. Main results. The simulated results indicated changes in the torque signal during the early phase of the disease while performing isotonic tasks, as well as in torque variability after partial conduction block while performing both isometric and isotonic tasks. Our results also indicated changes in the root mean square values and in the power spectrum of the soleus EMG signal as well as changes in the synchronisation index computed from the firing times of the active motor units. All these quantitative changes in functional indicators suggest that the adoption of such additional measurements, such as torques and ongoing EMG, could be used with advantage in the diagnosis and be relevant in providing extra information for the neurologist about the level of the disease. Significance. Our findings enrich the knowledge of the possible ways demyelination affects force generation and position control during plantarflexion. Moreover, this work extends computational neuroscience to computational neurology and shows the potential of biologically compatible neuromuscular computational models in providing relevant quantitative signs that may be useful for diagnosis in the clinic, complementing the tools traditionally used in neurological electrodiagnosis.
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16
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Peak counting in surface electromyography signals for quantification of muscle fatigue during dynamic contractions. Med Eng Phys 2022; 107:103844. [DOI: 10.1016/j.medengphy.2022.103844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 06/04/2022] [Accepted: 06/30/2022] [Indexed: 11/19/2022]
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17
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Pethick J, Taylor MJD, Harridge SDR. Ageing and skeletal muscle force control: current perspectives and future directions. Scand J Med Sci Sports 2022; 32:1430-1443. [PMID: 35815914 PMCID: PMC9541459 DOI: 10.1111/sms.14207] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 05/23/2022] [Accepted: 06/22/2022] [Indexed: 11/29/2022]
Abstract
During voluntary muscle contractions, force output is characterized by constant inherent fluctuations, which can be quantified either according to their magnitude or temporal structure, that is, complexity. The presence of such fluctuations when targeting a set force indicates that control of force is not perfectly accurate, which can have significant implications for task performance. Compared to young adults, older adults demonstrate a greater magnitude and lower complexity in force fluctuations, indicative of decreased steadiness, and adaptability of force output, respectively. The nature of this loss‐of‐force control depends not only on the age of the individual but also on the muscle group performing the task, the intensity and type of contraction and whether the task is performed with additional cognitive load. Importantly, this age‐associated loss‐of‐force control is correlated with decreased performance in a range of activities of daily living and is speculated to be of greater importance for functional capacity than age‐associated decreases in maximal strength. Fortunately, there is evidence that acute physical activity interventions can reverse the loss‐of‐force control in older individuals, though whether this translates to improved functional performance and whether lifelong physical activity can protect against the changes have yet to be established. A number of mechanisms, related to both motor unit properties and the behavior of motor unit populations, have been proposed for the age‐associated changes in force fluctuations. It is likely, though, that age‐associated changes in force control are related to increased common fluctuations in the discharge times of motor units.
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Affiliation(s)
- Jamie Pethick
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Essex, UK
| | - Matthew J D Taylor
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Essex, UK
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18
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Nakazawa K. Brain Reorganization and Neural Plasticity in Elite Athletes With Physical Impairments. Exerc Sport Sci Rev 2022; 50:118-127. [PMID: 35175230 PMCID: PMC9197146 DOI: 10.1249/jes.0000000000000288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/08/2021] [Indexed: 11/21/2022]
Abstract
Use-dependent and impairment-specific brain plasticity are hypothesized to interact and enhance neural reorganization in the central nervous system (CNS) of athletes with physical impairments. Paralympic brain studies are helpful in achieving a fundamental understanding of the underlying neural mechanism related to CNS reorganization after physical therapy or athletic training. Information learned from these individuals also provides new insights into sports- and rehabilitation-related neuroscience.
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19
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Carbonaro M, Zaccardi S, Seoni S, Meiburger KM, Botter A. Detecting anatomical characteristics of single motor units by combining high density electromyography and ultrafast ultrasound: a simulation study. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2022; 2022:748-751. [PMID: 36086608 DOI: 10.1109/embc48229.2022.9871578] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Muscle force production is the result of a sequence of electromechanical events that translate the neural drive issued to the motor units (MUs) into tensile forces on the tendon. Current technology allows this phenomenon to be investigated non-invasively. Single MU excitation and its mechanical response can be studied through high-density surface electromyography (HDsEMG) and ultrafast ultrasound (US) imaging respectively. In this study, we propose a method to integrate these two techniques to identify anatomical characteristics of single MUs. Specifically, we tested two algorithms, combining the tissue velocity sequence (TVS, obtained from ultrafast US images), and the MU firings (extracted from HDsEMG decomposition). The first is the Spike Triggered Averaging (STA) of the TVS based on the occurrences of individual MU firings, while the second relies on the correlation between the MU firing patterns and the TVS spatio-temporal independent components (STICA). A simulation model of the muscle contraction was adapted to test the algorithms at different degrees of neural excitation (number of active MUs) and MU synchronization. The performances of the two algorithms were quantified through the comparison between the simulated and the estimated characteristics of MU territories (size, location). Results show that both approaches are negatively affected by the number of active MU and synchronization levels. However, STICA provides a more robust MU territory estimation, outperforming STA in all the tested conditions. Our results suggest that spatio-temporal independent component decomposition of TVS is a suitable approach for anatomical and mechanical characterization of single MUs using a combined HDsEMG and ultrafast US approach.
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20
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Guo Y, Jones EJ, Inns TB, Ely IA, Stashuk DW, Wilkinson DJ, Smith K, Piasecki J, Phillips BE, Atherton PJ, Piasecki M. Neuromuscular recruitment strategies of the vastus lateralis according to sex. Acta Physiol (Oxf) 2022; 235:e13803. [PMID: 35184382 PMCID: PMC9286427 DOI: 10.1111/apha.13803] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 02/03/2022] [Accepted: 02/16/2022] [Indexed: 12/19/2022]
Abstract
AIM Despite males typically exhibiting greater muscle strength and fatigability than females, it remains unclear if there are sex-based differences in neuromuscular recruitment strategies e.g. recruitment and modulation of motor unit firing rate (MU FR) at normalized forces and during progressive increases in force. METHODS The study includes 29 healthy male and 31 healthy female participants (18-35 years). Intramuscular electromyography (iEMG) was used to record individual motor unit potentials (MUPs) and near-fibre MUPs from the vastus lateralis (VL) during 10% and 25% maximum isometric voluntary contractions (MVC), and spike-triggered averaging was used to obtain motor unit number estimates (MUNE) of the VL. RESULTS Males exhibited greater muscle strength (P < .001) and size (P < .001) than females, with no difference in force steadiness at 10% or 25% MVC. Females had 8.4% and 6.5% higher FR at 10% and 25% MVC, respectively (both P < .03), while the MUP area was 33% smaller in females at 10% MVC (P < .02) and 26% smaller at 25% MVC (P = .062). However, both sexes showed similar increases in MU size and FR when moving from low- to mid-level contractions. There were no sex differences in any near-fibre MUP parameters or in MUNE. CONCLUSION In the vastus lateralis, females produce muscle force via different neuromuscular recruitment strategies to males which is characterized by smaller MUs discharging at higher rates. However, similar strategies are employed to increase force production from low- to mid-level contractions. These findings of similar proportional increases between sexes support the use of mixed sex cohorts in studies of this nature.
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Affiliation(s)
- Yuxiao Guo
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Eleanor J. Jones
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Thomas B. Inns
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Isabel A. Ely
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Daniel W. Stashuk
- Department of Systems Design Engineering University of Waterloo Waterloo Ontario Canada
| | - Daniel J. Wilkinson
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Kenneth Smith
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Jessica Piasecki
- Musculoskeletal Physiology Research Group Sport, Health and Performance Enhancement Research Centre Nottingham Trent University Nottingham UK
| | - Bethan E. Phillips
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Philip J. Atherton
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
| | - Mathew Piasecki
- Centre of Metabolism Ageing & Physiology (COMAP) MRC‐Versus Arthritis Centre for Musculoskeletal Ageing Research and National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre School of Medicine University of Nottingham Derby UK
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21
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Costa-García Á, Iáñez E, Yokoyama M, Ueda S, Okajima S, Shimoda S. Quantification of high and low sEMG spectral components during sustained isometric contraction. Physiol Rep 2022; 10:e15296. [PMID: 35614546 PMCID: PMC9133435 DOI: 10.14814/phy2.15296] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 04/19/2022] [Indexed: 11/24/2022] Open
Abstract
Superficial Electromyography (sEMG) spectrum contains aggregated information from several underlying physiological processes. Due to technological limitations, the isolation of these processes is challenging, and therefore, the interpretation of changes in muscle activity frequency is still controversial. Recent studies showed that the spectrum of sEMG signals recorded from isotonic and short-term isometric contractions can be decomposed into independent components whose spectral features recall those of motor unit action potentials. In this paper sEMG spectral decomposition is tested during muscle fatigue induced by long-term isometric contraction where sEMG spectral changes have been widely studied. The main goals of this work are to validate spectral component extraction during long-term isometric muscle activation and the quantification of energy exchange between the low- and high-frequency bands of sEMG signals during muscle fatigue.
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Affiliation(s)
- Álvaro Costa-García
- CBS-TOYOTA Collaboration Center in the Nagoya Science Park Research and Development Center, Intelligent Behaviour Control Unit (RIKEN), Nagoya, Aichi, Japan
| | - Eduardo Iáñez
- Brain Machine Interface Systems Lab from Miguel Hernández University (UMH), Parque Cientifico UMH, Edificio Innova, Elche, Alicante, Spain
| | - Moeka Yokoyama
- CBS-TOYOTA Collaboration Center in the Nagoya Science Park Research and Development Center, Intelligent Behaviour Control Unit (RIKEN), Nagoya, Aichi, Japan
| | - Sayako Ueda
- CBS-TOYOTA Collaboration Center in the Nagoya Science Park Research and Development Center, Intelligent Behaviour Control Unit (RIKEN), Nagoya, Aichi, Japan
| | - Shotaro Okajima
- CBS-TOYOTA Collaboration Center in the Nagoya Science Park Research and Development Center, Intelligent Behaviour Control Unit (RIKEN), Nagoya, Aichi, Japan
| | - Shingo Shimoda
- CBS-TOYOTA Collaboration Center in the Nagoya Science Park Research and Development Center, Intelligent Behaviour Control Unit (RIKEN), Nagoya, Aichi, Japan
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22
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Ranaldi S, Corvini G, De Marchis C, Conforto S. The Influence of the sEMG Amplitude Estimation Technique on the EMG–Force Relationship. SENSORS 2022; 22:s22113972. [PMID: 35684590 PMCID: PMC9182811 DOI: 10.3390/s22113972] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/11/2022] [Accepted: 05/20/2022] [Indexed: 12/07/2022]
Abstract
The estimation of the sEMG–force relationship is an open problem in the scientific literature; current methods show different limitations and can achieve good performance only on limited scenarios, failing to identify a general solution to the optimization of this kind of analysis. In this work, this relationship has been estimated on two different datasets related to isometric force-tracking experiments by calculating the sEMG amplitude using different fixed-time constant moving-window filters, as well as an adaptive time-varying algorithm. Results show how the adaptive methods might be the most appropriate choice for the estimation of the correlation between the sEMG signal and the force time course. Moreover, the comparison between adaptive and standard filters highlights how the time constants exploited in the estimation strategy is not the only influence factor on this kind of analysis; a time-varying approach is able to constantly capture more information with respect to fixed stationary approaches with comparable window lengths.
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Affiliation(s)
- Simone Ranaldi
- Department of Industrial, Electronics and Mechanical Engineering, Roma Tre University, 00154 Roma, Italy; (S.R.); (G.C.)
| | - Giovanni Corvini
- Department of Industrial, Electronics and Mechanical Engineering, Roma Tre University, 00154 Roma, Italy; (S.R.); (G.C.)
| | | | - Silvia Conforto
- Department of Industrial, Electronics and Mechanical Engineering, Roma Tre University, 00154 Roma, Italy; (S.R.); (G.C.)
- Correspondence:
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Zheng Y, Xu G, Li Y, Qiang W. Improved online decomposition of non-stationary electromyogram via signal enhancement using a neuron resonance model: a simulation study. J Neural Eng 2022; 19. [PMID: 35303735 DOI: 10.1088/1741-2552/ac5f1b] [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: 12/10/2021] [Accepted: 03/18/2022] [Indexed: 11/12/2022]
Abstract
Objective. Motor unit (MU) discharge information obtained via the online electromyogram (EMG) decomposition has shown promising prospects in multiple applications. However, the nonstationarity of EMG signals caused by the rotation (recruitment-derecruitment) of MUs and the variation of MU action potentials (MUAP) can significantly degrade the online decomposition performance. This study aimed to develop an independent component analysis-based online decomposition method that can accommodate the nonstationarity of EMG signals.Approach. The EMG nonstationarity can make the separation vectors obtained beforehand inaccurate, resulting in the reduced amplitudes of the peaks corresponding to firing events in the source signal (independent component) and then the decreased accuracy of firing events. Therefore, we utilized the FitzHugh-Nagumo (FHN) resonance model to enhance the firing peaks in the source signal in order to improve the decomposition accuracy. A two-session approach was used with the offline session to extract the separation vectors and train the FHN models. In the online session, the source signal was estimated and further processed using the FHN model before detecting the firing events in a real-time manner. The proposed method was tested on simulated EMG signals, in which MU rotation and MUAP variation were involved to mimic the nonstationarity of EMG recordings.Main results. Compared with the conventional method, the proposed method can improve the decomposition accuracy significantly (88.70% ± 4.17% vs. 92.43% ± 2.79%) by enhancing the firing peaks, and more importantly, the improvement was more prominent when the EMG signal had stronger background noises (87.00% ± 3.70% vs. 91.66% ± 2.63%).Conclusions. Our results demonstrated the effectiveness of the proposed method to utilize the FHN model to improve the online decomposition performance on the nonstationary EMG signals. Further development of our method has the potential to improve the performance of the neural decoding system that utilizes the MU discharge information and promote its application in the neural-machine interface.
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Affiliation(s)
- Yang Zheng
- Institute of Engineering & Medicine Interdisciplinary Studies, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China.,State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Guanghua Xu
- Institute of Engineering & Medicine Interdisciplinary Studies, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China.,State Key Laboratory for Manufacturing Systems Engineering, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Yixin Li
- Institute of Engineering & Medicine Interdisciplinary Studies, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
| | - Wei Qiang
- Institute of Engineering & Medicine Interdisciplinary Studies, School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049, People's Republic of China
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Fixational drift is driven by diffusive dynamics in central neural circuitry. Nat Commun 2022; 13:1697. [PMID: 35361753 PMCID: PMC8971408 DOI: 10.1038/s41467-022-29201-y] [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: 01/21/2021] [Accepted: 03/04/2022] [Indexed: 11/08/2022] Open
Abstract
During fixation and between saccades, our eyes undergo diffusive random motion called fixational drift. The role of fixational drift in visual coding and inference has been debated in the past few decades, but the mechanisms that underlie this motion remained unknown. In particular, it has been unclear whether fixational drift arises from peripheral sources, or from central sources within the brain. Here we show that fixational drift is correlated with neural activity, and identify its origin in central neural circuitry within the oculomotor system, upstream to the ocular motoneurons (OMNs). We analyzed a large data set of OMN recordings in the rhesus monkey, alongside precise measurements of eye position, and found that most of the variance of fixational eye drifts must arise upstream of the OMNs. The diffusive statistics of the motion points to the oculomotor integrator, a memory circuit responsible for holding the eyes still between saccades, as a likely source of the motion. Theoretical modeling, constrained by the parameters of the primate oculomotor system, supports this hypothesis by accounting for the amplitude as well as the statistics of the motion. Thus, we propose that fixational ocular drift provides a direct observation of diffusive dynamics in a neural circuit responsible for storage of continuous parameter memory in persistent neural activity. The identification of a mechanistic origin for fixational drift is likely to advance the understanding of its role in visual processing and inference.
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Low-Frequency Oscillations and Force Control Capabilities as a Function of Force Level in Older Women. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12041812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Force variability is potentially related to altered low-frequency oscillations in motor outputs. This study examines the contributions of low-frequency oscillations in force to altered force control performances from lower to higher targeted force levels in older women. Fourteen older women executed unilateral hand-grip force control tasks at 10% and 40% of maximum voluntary contraction (MVC). Force control performances were estimated by calculating force accuracy (root-mean-square-error), force variability (standard deviation), and force regularity (approximate entropy). We additionally quantified low-frequency oscillations in force using absolute powers across four different frequency bands: (a) 0–0.5 Hz, (b) 0.5–1.0 Hz, (c) 1.0–1.5 Hz, and (d) 1.5–2.0 Hz. The findings reveal that from lower to higher targeted force level older women show greater force error, force variability, and force regularity with increased values of absolute power in force across the four frequency bands. The multiple regression models identified a significant relationship between greater force frequency power below 0.5 Hz and more impairments in force control performances. These findings suggest that force frequency oscillation below 0.5 Hz is a key predictor indicating altered stability of task performances across different targeted force levels in older women.
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Novak TS, Wilson SM, Newell KM. Establishing Task-Relevant MVC Protocols for Modelling Sustained Isometric Force Variability: A Manual Control Study. J Funct Morphol Kinesiol 2021; 6:jfmk6040094. [PMID: 34842771 PMCID: PMC8628892 DOI: 10.3390/jfmk6040094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/27/2021] [Accepted: 10/29/2021] [Indexed: 11/27/2022] Open
Abstract
The present study examined how prevalent methods for determining maximal voluntary contraction (MVC) impact the experimentally derived functions of graded force-force variability. Thirty-two young healthy subjects performed continuous isometric force tracking (20 s trials) at 10 target percentages (5-95% MVC) normalized to a conventional discrete-point (n = 16), or sustained (n = 16) MVC calculation. Distinct rates and magnitudes of change were observed for absolute variability (standard deviation (SD), root mean squared error (RMSE)), tracking error (RMSE, constant error (CE)), and complexity (detrended fluctuation analysis (DFA)) (all p < 0.05) of graded force fluctuations between the MVC groups. Differential performance strategies were observed beyond ~65% MVC, with the discrete-point group minimizing their SD at force values below that of the criterion target (higher CE/RMSE). Moreover, the sustained group's capacity to minimize SD/RMSE/CE corresponded to a more complex structure in their force fluctuations. These findings reveal that the time component of MVC estimation has a direct influence on the corrective strategies supporting near-maximal manual force control. While discrete MVC protocols predominate in the study of manual strength/endurance/precision, a 1:1 MVC-task mapping appears more to be ecologically valid if visuo-motor precision outcomes are of central importance.
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Affiliation(s)
- Thomas S. Novak
- Department of Kinesiology, University of Georgia, 330 River Rd., Athens, GA 30602, USA; (S.M.W.); (K.M.N.)
- VA Rehabilitation R&D Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, 1670 Clairmont Rd., Decatur, GA 30033, USA
- Correspondence:
| | - Shane M. Wilson
- Department of Kinesiology, University of Georgia, 330 River Rd., Athens, GA 30602, USA; (S.M.W.); (K.M.N.)
| | - Karl M. Newell
- Department of Kinesiology, University of Georgia, 330 River Rd., Athens, GA 30602, USA; (S.M.W.); (K.M.N.)
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Promsri A. Modulation of bilateral lower-limb muscle coordination when performing increasingly challenging balance exercises. Neurosci Lett 2021; 767:136299. [PMID: 34699944 DOI: 10.1016/j.neulet.2021.136299] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 10/10/2021] [Accepted: 10/17/2021] [Indexed: 11/16/2022]
Abstract
Balance exercises have proven effective in enhancing and regaining neuromuscular control. However, how the bilateral homonymous muscles are coordinated to achieve bipedal equilibrium remains unclear. In terms of increasingly difficult balance tasks, the current study focused on two levels of muscle coordination: individual homonymous muscles and groups of homonymous muscles. In 25 physically active young adults, a cross-correlation between the bilateral electromyographic (EMG) signals of both legs (i.e., bilateral EMG-EMG correlation) was conducted on seven muscles measured when performing bipedal balancing on three different support surface instabilities. Then, the patterns of bilateral EMG-EMG cross-correlation coefficients were determined through a principal component analysis (PCA). It was hypothesized that modulations of bilateral lower-limb muscle coordination should be observed in the specific relevant muscles or in the patterns of bilateral muscle coordination. The results showed that only the first hypothesis was supported as changes in the strength of bilateral EMG-EMG correlation (p ≤ 0.005) and in the time delays (p < 0.001) were mostly restricted in the lower-leg muscles. The dorsiflexor and plantar flexor muscles showed opposite coordination behaviors. Larger bilateral EMG-EMG correlation and shorter time delays appeared only in the tibialis anterior muscle, suggesting that bilateral dorsiflexor muscle coordination is needed for exercising on multiaxial-unstable platforms.
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Affiliation(s)
- Arunee Promsri
- Department of Physical Therapy, School of Allied Health Sciences, University of Phayao, 19 Moo 2, Maeka, Muang, Phayao 56000, Thailand; Department of Sport Science, University of Innsbruck, Fürstenweg 185, 6020 Innsbruck, Austria; Unit of Excellence in Well-Being and Health Innovation, School of Allied Health Sciences, University of Phayao, 19 Moo 2, Maeka, Muang, Phayao 56000, Thailand.
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Pickett CW, Nosaka K, Zois J, Blazevich AJ. Relationships Between Midthigh Pull Force Development and 200-m Race Performance in Highly Trained Kayakers. J Strength Cond Res 2021; 35:2853-2861. [PMID: 31232830 DOI: 10.1519/jsc.0000000000003235] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Pickett, CW, Nosaka, K, Zois, J, and Blazevich, AJ. Relationships between midthigh pull force development and 200-m race performance in highly trained kayakers. J Strength Cond Res 35(10): 2853-2861, 2021-While increased lower-limb force production during kayaking has been shown to be related to increased boat velocity, poor relationships between maximal deadlift test performances and 200-m race time have been observed previously. This discrepancy may result from either a lack of movement pattern or temporal force production specificity between the test and kayak paddling. The isometric midthigh pull (MTP) test is commonly used in strength testing and quantifies temporal and peak force production, with the lower limbs positioned in a more kayak-specific manner than the deadlift test. Midthigh pull force data collected from 11 high-level kayak athletes were analyzed for both reliability and correlations with 200-m race time and deadlift isoinertial strength 3 repetition maximum (3RM). Strong consideration was given to the collection, processing, and analysis of the MTP data, which markedly affected the study results. Correlations between race time and MTP peak force and rates of force development were poor to moderate (r = -0.49 to 0.07). Strong to very strong relationships (r = 0.66-0.79) were found between forces developed early in the MTP (<0.15 seconds) and deadlift 3RM strength tests but were poor for later time-specific force development (r ≤ 0.12). However, poor reliability was found for force measured up to ≤0.25 seconds from the point of force onset (intraclass correlation coefficient >0.8). Owing to the relatively weak relationships with 200-m race time, and the large variability of the data, it may not be wise to include the MTP in the testing and training of 200-m kayak athletes.
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Affiliation(s)
- Craig W Pickett
- Center for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Australia
- Institute for Health and Sport, Victoria University, Footscray Park, Australia ; and
- Center for Health and Biomedicine, Victoria University, Footscray Park, Australia
| | - Kazunori Nosaka
- Center for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Australia
| | - James Zois
- Institute for Health and Sport, Victoria University, Footscray Park, Australia ; and
| | - Anthony J Blazevich
- Center for Exercise and Sports Science Research, School of Medical and Health Sciences, Edith Cowan University, Australia
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Huang C, Chen M, Li X, Zhang Y, Li S, Zhou P. Neurophysiological Factors Affecting Muscle Innervation Zone Estimation Using Surface EMG: A Simulation Study. BIOSENSORS-BASEL 2021; 11:bios11100356. [PMID: 34677312 PMCID: PMC8534086 DOI: 10.3390/bios11100356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/16/2021] [Accepted: 09/24/2021] [Indexed: 11/16/2022]
Abstract
Surface electromyography (EMG) recorded by a linear or 2-dimensional electrode array can be used to estimate the location of muscle innervation zones (IZ). There are various neurophysiological factors that may influence surface EMG and thus potentially compromise muscle IZ estimation. The objective of this study was to evaluate how surface-EMG-based IZ estimation might be affected by different factors, including varying degrees of motor unit (MU) synchronization in the case of single or double IZs. The study was performed by implementing a model simulating surface EMG activity. Three different MU synchronization conditions were simulated, namely no synchronization, medium level synchronization, and complete synchronization analog to M wave. Surface EMG signals recorded by a 2-dimensional electrode array were simulated from a muscle with single and double IZs, respectively. For each situation, the IZ was estimated from surface EMG and compared with the one used in the model for performance evaluation. For the muscle with only one IZ, the estimated IZ location from surface EMG was consistent with the one used in the model for all the three MU synchronization conditions. For the muscle with double IZs, at least one IZ was appropriately estimated from interference surface EMG when there was no MU synchronization. However, the estimated IZ was different from either of the two IZ locations used in the model for the other two MU synchronization conditions. For muscles with a single IZ, MU synchronization has little effect on IZ estimation from electrode array surface EMG. However, caution is required for multiple IZ muscles since MU synchronization might lead to false IZ estimation.
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Affiliation(s)
- Chengjun Huang
- Guangdong Work Injury Rehabilitation Center, Guangzhou 510970, China;
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, TX 77030, USA;
| | - Maoqi Chen
- Faculty of Rehabilitation Engineering, University of Health and Rehabilitation Sciences, Qingdao 266024, China;
| | - Xiaoyan Li
- Department of Bioengineering, University of Maryland, College Park, MD 20742, USA;
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Yingchun Zhang
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204, USA;
| | - Sheng Li
- Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, Houston, TX 77030, USA;
| | - Ping Zhou
- Faculty of Rehabilitation Engineering, University of Health and Rehabilitation Sciences, Qingdao 266024, China;
- Correspondence:
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Zheng Y, Hu X. Adaptive Real-time Decomposition of Electromyogram During Sustained Muscle Activation: A Simulation Study. IEEE Trans Biomed Eng 2021; 69:645-653. [PMID: 34357862 DOI: 10.1109/tbme.2021.3102947] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE Real-time decomposition of electromyogram (EMG) into constituent motor unit (MU) activity has shown promising applications in neurophysiology and human-machine interactions. Existing decomposition methods could not accommodate stochastic variations in EMG signals such as drifts of action potential amplitudes and MU recruitment-derecruitment (rotation) patterns during long-term recordings. The objective of this study was to develop an adaptive real-time decomposition approach suitable for prolonged muscle activation. METHODS We developed a parallel-double-thread computation algorithm. The backend thread initiated and periodically refined and updated the MU information (separation matrix) using independent component analysis and convolution kernel compensation. The frontend thread performed the real-time decomposition. We evaluated our algorithm on synthesized high-density EMG signals, in which MUs were recruited-derecruited sporadically and MU action potentials amplitude drifted over time. Different signal-to-noise levels were also simulated. RESULTS Compared with the decomposition without the adaptive processes, periodically fine-tuned and updated separation matrix increased identifiable MU number by 3-4 fold over 30-minute of recordings. The increased MU number was more prominent at higher signal-to-noise ratios. The decomposition accuracy also increased by up to 10% with greater improvement observed at higher muscle contraction levels. CONCLUSION The adaptive algorithm can maintain the decomposition performance over time, allows us to continuously track the same MUs during sustained activation, and, at the same time, can add newly recruited MU information to existing separation matrix. SIGNIFICANCE Our approach showed robust performance over time, which has the potential to longitudinally evaluate MU firing and recruitment properties and improve neural decoding performance for neural-machine interactions.
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Fatigue-induced changes in knee-extensor torque complexity and muscle metabolic rate are dependent on joint angle. Eur J Appl Physiol 2021; 121:3117-3131. [PMID: 34355267 PMCID: PMC8505307 DOI: 10.1007/s00421-021-04779-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 07/25/2021] [Indexed: 01/20/2023]
Abstract
Purpose Joint angle is a significant determinant of neuromuscular and metabolic function. We tested the hypothesis that previously reported correlations between knee-extensor torque complexity and metabolic rate (\documentclass[12pt]{minimal}
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\begin{document}$${\text{m}\dot{\text{V}}\text{O}}_{{2}}$$\end{document}mV˙O2) would be conserved at reduced joint angles (i.e. shorter muscle lengths). Methods Eleven participants performed intermittent isometric knee-extensor contractions at 50% maximum voluntary torque for 30 min or until task failure (whichever occurred sooner) at joint angles of 30º, 60º and 90º of flexion (0º = extension). Torque and surface EMG were sampled continuously. Complexity and fractal scaling of torque were quantified using approximate entropy (ApEn) and detrended fluctuation analysis (DFA) α. \documentclass[12pt]{minimal}
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\begin{document}$${\text{m}\dot{\text{V}}\text{O}}_{{2}}$$\end{document}mV˙O2 was determined using near-infrared spectroscopy. Results Time to task failure/end increased as joint angle decreased (P < 0.001). Over time, complexity decreased at 90º and 60º (decreased ApEn, increased DFA α, both P < 0.001), but not 30º. \documentclass[12pt]{minimal}
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\begin{document}$${\text{m}\dot{\text{V}}\text{O}}_{{2}}$$\end{document}mV˙O2 increased at all joint angles (P < 0.001), though the magnitude of this increase was lower at 30º compared to 60º and 90º (both P < 0.01). There were significant correlations between torque complexity and \documentclass[12pt]{minimal}
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\begin{document}$${\text{m}\dot{\text{V}}\text{O}}_{{2}}$$\end{document}mV˙O2 at 90º (ApEn, r = − 0.60, P = 0.049) and 60º (ApEn, r = − 0.64, P = 0.035; DFA α, ρ = 0.68, P = 0.015). Conclusion The lack of correlation between \documentclass[12pt]{minimal}
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\begin{document}$${\text{m}\dot{\text{V}}\text{O}}_{{2}}$$\end{document}mV˙O2 and complexity at 30º was likely due to low relative task demands, given the similar kinetics of \documentclass[12pt]{minimal}
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\begin{document}$${\text{m}\dot{\text{V}}\text{O}}_{{2}}$$\end{document}mV˙O2 and torque complexity. An inverse correlation between \documentclass[12pt]{minimal}
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\begin{document}$${\text{m}\dot{\text{V}}\text{O}}_{{2}}$$\end{document}mV˙O2 and knee-extensor torque complexity occurs during high-intensity contractions at intermediate, but not short, muscle lengths.
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Characteristics of rectus femoris activation and rectus femoris-hamstrings coactivation during force-matching isometric knee extension in subacute stroke. Exp Brain Res 2021; 239:2621-2633. [PMID: 34213633 DOI: 10.1007/s00221-021-06162-0] [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: 05/03/2021] [Accepted: 06/22/2021] [Indexed: 10/20/2022]
Abstract
The spectral properties of surface electromyographic (EMG) signal in the rectus femoris (RF) and the coactivation in the medial hamstrings (MH) were investigated in 45 stroke subjects (22 ± 12 days post-onset) and 30 age-matched healthy controls who performed unilateral knee extensions at maximum effort (100% MVC) and during 5-s force-matching tasks (10, 30, 50% MVC). The spectral properties were obtained through a power spectrum analysis based on Fast Fourier Transform. The coactivation was measured as the MH amplitude (%max) and MH/RF amplitude ratio. Force variability was expressed as the coefficient of variation. Both knee extensors and flexors were weaker in the paretic leg than the non-paretic and control legs (p < 0.001). A significantly higher relative power in the 5-13 and 13-30 Hz bands was found in the paretic than the non-paretic leg across all force levels (p ≤ 0.001) without changes in the 30-60 and 60-100 Hz bands or the mean and median frequencies. Regarding the antagonist coactivation, MH amplitude in the paretic leg was higher than in the non-paretic leg (submaximal levels, p < 0.0001) and the control leg (all force levels, p = 0.0005) with no differences between legs in the MH/RF ratio. The steadiness of the knee extension force was not related to the spectral properties of the agonist EMG or antagonistic coactivation. Greater coactivation was associated with weaker paretic knee flexors (p ≤ 0.0002). The overall results suggest variably altered agonist activation and antagonistic coactivation over the range of isometric knee extension contractions in subacute stroke.
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Chatain C, Ramdani S, Vallier JM, Gruet M. Recurrence quantification analysis of force signals to assess neuromuscular fatigue in men and women. Biomed Signal Process Control 2021. [DOI: 10.1016/j.bspc.2021.102593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Model-Based Analysis of Muscle Strength and EMG-Force Relation with respect to Different Patterns of Motor Unit Loss. Neural Plast 2021; 2021:5513224. [PMID: 34257638 PMCID: PMC8245245 DOI: 10.1155/2021/5513224] [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: 02/12/2021] [Revised: 05/02/2021] [Accepted: 06/01/2021] [Indexed: 01/07/2023] Open
Abstract
This study presents a model-based sensitivity analysis of the strength of voluntary muscle contraction with respect to different patterns of motor unit loss. A motor unit pool model was implemented including simulation of a motor neuron pool, muscle force, and surface electromyogram (EMG) signals. Three different patterns of motor unit loss were simulated, including (1) motor unit loss restricted to the largest ones, (2) motor unit loss restricted to the smallest ones, and (3) motor unit loss without size restriction. The model outputs including muscle force amplitude, variability, and the resultant EMG-force relation were quantified under two different motor neuron firing strategies. It was found that motor unit loss restricted to the largest ones had the most dominant impact on muscle strength and significantly changed the EMG-force relation, while loss restricted to the smallest motor units had a pronounced effect on force variability. These findings provide valuable insight toward our understanding of the neurophysiological mechanisms underlying experimental observations of muscle strength, force control, and EMG-force relation in both normal and pathological conditions.
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Reeves J, McLean L. The influence of contraction type, prior performance of a maximal voluntary contraction and measurement duration on fine-wire EMG amplitude. J Electromyogr Kinesiol 2021; 59:102566. [PMID: 34139549 DOI: 10.1016/j.jelekin.2021.102566] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 04/22/2021] [Accepted: 06/02/2021] [Indexed: 11/30/2022] Open
Abstract
We aimed to investigate the impact of time on fine-wire (fw) electromyography (EMG) signal amplitude, and to determine whether any attenuation is confounded by task type. Twenty healthy participants were instrumented with fw and surface (s) EMG electrodes at the biceps brachii bilaterally. Participants held a weight statically with one arm and with the other arm either repeated the same task following a maximum voluntary contraction (MVC) or repeated dynamic elbow flexion/extension contractions. Each task was repeated for 30 s every five minutes over two hours. EMG amplitude was smoothed and normalized to time = 0. Stable median power frequency of the s-EMG ruled out the confounding influence of fatigue. Repeated-measures ANCOVAs determined the effect of electrode type and time (covariate) on EMG amplitude and the confounding impact of task type. During the isometric protocol, fw-EMG amplitude reduced over time (p = 0.002), while s-EMG amplitude (p = 0.895) and MPF (p > 0.05) did not change. Fw-EMG amplitude attenuated faster during the dynamic than the isometric protocol (p = 0.008) and there was evidence that the MVC preceding the isometric protocol impacted the rate of decline (p = 0.001). We conclude that systematic signal attenuation of fw-EMG occurs over time and is more pronounced during dynamic tasks.
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Affiliation(s)
- Joanna Reeves
- Faculty of Health Sciences, University of Ottawa, Ottawa, Canada; School of Sport, Health and Exercise Science, Spinnaker Building, University of Portsmouth, PO1 2ER, United Kingdom
| | - Linda McLean
- Faculty of Health Sciences, University of Ottawa, Ottawa, Canada
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36
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Walker S. Evidence of resistance training-induced neural adaptation in older adults. Exp Gerontol 2021; 151:111408. [PMID: 34022275 DOI: 10.1016/j.exger.2021.111408] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 05/04/2021] [Accepted: 05/17/2021] [Indexed: 11/25/2022]
Abstract
The deleterious effects of aging on force production are observable from the age of 40 upwards, depending on the measure. Neural mechanisms contributing to maximum force production and rate of force development have been suggested as descending drive from supraspinal centers, spinal motoneuron excitability, and corticospinal inhibition of descending drive; all of which influence motor unit recruitment and/or firing rate. Resistance-trained Master athletes offer a good source of information regarding the inevitable effects of aging despite the countermeasure of systematic resistance-training. However, most evidence of neural adaptation is derived from longitudinal intervention studies in previously untrained (i.e. resistance-training naïve) older adults. There is good evidence for the effect of resistance-training on the end-point of neural activation, i.e. motor unit behavior, but little to no data on the generation of descending drive from e.g. transcranial magnetic stimulation or cortical imaging studies in older adults. This, along with tracking master athletes over several years, would provide valuable information and could be the focus of future research.
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Affiliation(s)
- Simon Walker
- NeuroMuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, Finland.
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37
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Schlink BR, Nordin AD, Brooks CN, Ferris DP. Fatigue induces altered spatial myoelectric activation patterns in the medial gastrocnemius during locomotion. J Neurophysiol 2021; 125:2013-2023. [PMID: 33909489 DOI: 10.1152/jn.00602.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
This research investigates the effects of muscle fatigue on spatial myoelectric patterns in the lower limb during locomotion. Both spatial and frequency aspects of neuromuscular recruitment in the medial gastrocnemius change in response to fatigue, resulting in altered myoelectric patterns during walking and running. These data may help us better understand the adaptations that occur in lower limb muscles to avoid overuse injuries caused by fatigue.
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Affiliation(s)
- Bryan R Schlink
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida
| | - Andrew D Nordin
- Department of Health and Kinesiology, Texas A&M University, College Station, Texas
| | - Christina N Brooks
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida
| | - Daniel P Ferris
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida
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38
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Effect of synchronization of firings of different motor unit types on the force variability in a model of the rat medial gastrocnemius muscle. PLoS Comput Biol 2021; 17:e1008282. [PMID: 33901164 PMCID: PMC8101995 DOI: 10.1371/journal.pcbi.1008282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 05/06/2021] [Accepted: 04/07/2021] [Indexed: 11/19/2022] Open
Abstract
The synchronized firings of active motor units (MUs) increase the oscillations of muscle force, observed as physiological tremor. This study aimed to investigate the effects of synchronizing the firings within three types of MUs (slow—S, fast resistant to fatigue–FR, and fast fatigable–FF) on the muscle force production using a mathematical model of the rat medial gastrocnemius muscle. The model was designed based on the actual proportion and physiological properties of MUs and motoneurons innervating the muscle. The isometric muscle and MU forces were simulated by a model predicting non-synchronized firing of a pool of 57 MUs (including 8 S, 23 FR, and 26 FF) to ascertain a maximum excitatory signal when all MUs were recruited into the contraction. The mean firing frequency of each MU depended upon the twitch contraction time, whereas the recruitment order was determined according to increasing forces (the size principle). The synchronization of firings of individual MUs was simulated using four different modes and inducing the synchronization of firings within three time windows (± 2, ± 4, and ± 6 ms) for four different combinations of MUs. The synchronization was estimated using two parameters, the correlation coefficient and the cross-interval synchronization index. The four scenarios of synchronization increased the values of the root-mean-square, range, and maximum force in correlation with the increase of the time window. Greater synchronization index values resulted in higher root-mean-square, range, and maximum of force outcomes for all MU types as well as for the whole muscle output; however, the mean spectral frequency of the forces decreased, whereas the mean force remained nearly unchanged. The range of variability and the root-mean-square of forces were higher for fast MUs than for slow MUs; meanwhile, the relative values of these parameters were highest for slow MUs, indicating their important contribution to muscle tremor, especially during weak contractions. The synchronization of firings of motor units (MUs), the smallest functional elements of skeletal muscle increases fluctuations in muscle force, known as physiological tremor, which can disturb high-precision movements. In this study, we adopted a recently proposed muscle model consisting of MUs of three different types (fast fatigable, fast resistant to fatigue, and slow) to study four different scenarios of MU synchronization during a steady level of excitatory input to motoneurons. The discharge patterns were synchronized between pairs of MUs by shifting in time individual pulses, which occurred within a short time interval, and a degree of synchronization was then estimated. The increased synchronization index resulted in increased force variability for all MU types as well as for the whole muscle output; however, the mean force levels remained nearly unchanged, whereas the frequencies of the force oscillations were decreased. The absolute range of force variability was higher for fast than for slow MUs, indicating their dominant influence on muscle tremor at strong contractions, but the highest relative increase in force variability was observed for synchronized slow MUs, indicating their significant contribution to tremor during weak contractions, in which only slow MUs are active.
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39
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Temporal Changes in Electromyographic Activity and Gait Ability during Extended Walking in Individuals Post-Stroke: A Pilot Study. Healthcare (Basel) 2021; 9:healthcare9040444. [PMID: 33920156 PMCID: PMC8070003 DOI: 10.3390/healthcare9040444] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 03/29/2021] [Accepted: 04/08/2021] [Indexed: 11/24/2022] Open
Abstract
Abnormal gait, particularly in patients with stroke, causes neuromuscular fatigue. We aimed to clarify temporal changes in gait performance and lower limb muscle activity during extended walking in people with stroke hemiplegia. Twelve adults with stroke and eleven healthy controls performed an extended trial involving 20-min continuous walk at a comfortable speed. The primary outcome was electromyography amplitude during the trial and secondary outcomes were walking performance and the instantaneous mean frequency of electromyography during the trial. Data at 1, 6, 12, and 18 min after initiating walking were compared. Performance during extended walking in people with stroke was maintained over time. The electromyography amplitude decreased in the tibialis anterior during the pre-swing phase and increased in the rectus femoris during the single-support phase over time; these changes were similar on the paretic and nonparetic sides. Instantaneous mean frequency decreased over time on the nonparetic side in the tibialis anterior and on the paretic side in the rectus femoris. Healthy subjects did not show any changes over time. The changes in muscle activity in patients with stroke differed between the paretic and nonparetic sides, muscle type, and gait phase; walking performance was maintained despite being affected by neuromuscular fatigue.
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40
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Inglis JG, Gabriel DA. Sex differences in the modulation of the motor unit discharge rate leads to reduced force steadiness. Appl Physiol Nutr Metab 2021; 46:1065-1072. [PMID: 33667116 DOI: 10.1139/apnm-2020-0953] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to evaluate the relationship between the variability in the motor unit inter-pulse interval and force steadiness at submaximal and maximal force outputs between the sexes. Twenty-four male and 24 female participants were recruited to perform isometric dorsiflexion contractions at 20, 40, 60, 80, and 100% maximum voluntary contraction. Tibialis anterior myoelectric signal was recorded by an intramuscular electrode. Females had lower force steadiness (coefficient of variation of force (CoV-Force), 27.3%, p < 0.01) and a greater coefficient of variation of motor unit action potential inter-pulse interval (CoV-IPI), compared with males (9.6%, p < 0.01). There was no significant correlation between the normalized CoV-IPI and CoV-Force (r = 0.19, p > 0.01), but there was a significant repeated measures correlation between the raw scores for root-mean-square force error and the standard deviation of motor unit discharge rate (r = 0.65, p < 0.01). Females also had a greater incidence of doublet discharges on average across force levels (p < 0.01). The sex differences may result from motor unit behaviours (i.e., doublet and rapid discharges, synchronization, rate coding or recruitment), leading to lower force steadiness and greater CoV-IPI in females. Novelty: Sex differences in force steadiness may be due to neural strategies. Females have lower force steadiness compared with males. Greater incidence of doublet discharges in females may result in lesser force steadiness.
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Affiliation(s)
- J Greig Inglis
- Electromyographic Kinesiology Laboratory, Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada.,Electromyographic Kinesiology Laboratory, Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - David A Gabriel
- Electromyographic Kinesiology Laboratory, Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada.,Electromyographic Kinesiology Laboratory, Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada
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41
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Nagamori A, Laine CM, Loeb GE, Valero-Cuevas FJ. Force variability is mostly not motor noise: Theoretical implications for motor control. PLoS Comput Biol 2021; 17:e1008707. [PMID: 33684099 PMCID: PMC7971898 DOI: 10.1371/journal.pcbi.1008707] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 03/18/2021] [Accepted: 01/15/2021] [Indexed: 11/19/2022] Open
Abstract
Variability in muscle force is a hallmark of healthy and pathological human behavior. Predominant theories of sensorimotor control assume 'motor noise' leads to force variability and its 'signal dependence' (variability in muscle force whose amplitude increases with intensity of neural drive). Here, we demonstrate that the two proposed mechanisms for motor noise (i.e. the stochastic nature of motor unit discharge and unfused tetanic contraction) cannot account for the majority of force variability nor for its signal dependence. We do so by considering three previously underappreciated but physiologically important features of a population of motor units: 1) fusion of motor unit twitches, 2) coupling among motoneuron discharge rate, cross-bridge dynamics, and muscle mechanics, and 3) a series-elastic element to account for the aponeurosis and tendon. These results argue strongly against the idea that force variability and the resulting kinematic variability are generated primarily by 'motor noise.' Rather, they underscore the importance of variability arising from properties of control strategies embodied through distributed sensorimotor systems. As such, our study provides a critical path toward developing theories and models of sensorimotor control that provide a physiologically valid and clinically useful understanding of healthy and pathologic force variability.
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Affiliation(s)
- Akira Nagamori
- Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, California, United States of America
| | - Christopher M. Laine
- Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, California, United States of America
- Chan Division of Occupational Science and Occupational Therapy, University of Southern California, Los Angeles, California, United States of America
| | - Gerald E. Loeb
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, United States of America
| | - Francisco J. Valero-Cuevas
- Division of Biokinesiology and Physical Therapy, University of Southern California, Los Angeles, California, United States of America
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, United States of America
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42
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Amiri P, Kearney RE. Identification of Central and Stretch Reflex Contributions to Human Postural Control. IEEE Trans Neural Syst Rehabil Eng 2021; 29:497-507. [PMID: 33556012 DOI: 10.1109/tnsre.2021.3057785] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Human postural control requires continuous modulation of ankle torque to stabilize the upright stance. The torque is generated by two components: active contributions, due to central control and stretch reflex, and passive mechanisms, due to joint intrinsic stiffness. Identifying the contribution of each component is difficult, since their effects appear together, and standing is controlled in closed-loop. This article presents a novel multiple-input, single-output method to identify central and stretch reflex contributions to human postural control. The model uses ankle muscle EMGs as inputs and requires no kinematic data. Application of the method to data from nine subjects during standing while subjected to perturbations of ankle position demonstrated that active torque accounted for 84.0± 5.5% of the ankle torque. The ankle plantar-flexors collectively produced the largest portion of the active torque through central control, with large inter-subject variability in the relative contributions of the individual muscles. In addition, reflex contribution of the plantar-flexors was substantial in half of the subjects, showing its potentially important functional role; finally, intrinsic contributions, estimated as the residual of the model, contributed to 15% of the torque. This study introduces a new method to quantify the contributions of the central and stretch reflex pathways to postural control; the method also provides an estimate of noisy intrinsic torque with significantly increased signal to noise ratio, suitable for identification of intrinsic stiffness in standing. The method can be used in different experimental conditions and requires minimal a-priori assumption regarding the role of different pathways in postural control.
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43
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Morozumi K, Ohsugi H, Morishita K, Yokoi Y. Fundamental research on surface electromyography analysis using discrete wavelet transform-an analysis of the central nervous system factors affecting muscle strength. J Phys Ther Sci 2021; 33:63-68. [PMID: 33519077 PMCID: PMC7829554 DOI: 10.1589/jpts.33.63] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 10/25/2020] [Indexed: 12/04/2022] Open
Abstract
[Purpose] We aimed to investigate the central nervous system factors that affect muscle
strength based on the differences in load and time using the discrete wavelet transform,
which is capable of a time-frequency-potential analysis. [Participants and Methods]
Surface electromyography (EMG) of the right upper bicep muscle in 16 healthy adult males
were measured at 10% MVC (maximum voluntary isometric contraction), 30%, 50%, 70%, and 80%
to 100% MVC. We used a discrete wavelet transform for the electromyographic analysis and
calculated the median instantaneous frequency spectrum (MDF) and frequency band component
content rate (FCR) at 1-ms intervals as well as their spectrum integrated values (I-EMG).
[Results] MDF and FCR tended to be high throughout the measurements. Specifically, the
high-frequency band component content rate was high at the time of low muscle strength;
fast-twitch muscle fibers may be involved during these muscle contractions. We found
significant changes in the I-EMG as the muscle strength increased from 10% MVC to 100%
MVC. [Conclusion] Analyzing the surface electromyograph using discrete wavelet transform
enabled us to assess the central nervous system factors that increase in the EMG amplitude
integrated values and change in the median instantaneous frequency spectrum and in the
frequency band component content rate.
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Affiliation(s)
- Kazunori Morozumi
- Department of Physical Therapy, Faculty of Social Work Studies, Josai International University: 1 Gumyo, Togane, Chiba 283-8555, Japan
| | - Hironori Ohsugi
- Department of Physical Therapy, Faculty of Social Work Studies, Josai International University: 1 Gumyo, Togane, Chiba 283-8555, Japan
| | - Katsuyuki Morishita
- Department of Physical Therapy, Faculty of Social Work Studies, Josai International University: 1 Gumyo, Togane, Chiba 283-8555, Japan
| | - Yuka Yokoi
- Department of Physical Therapy, Faculty of Social Work Studies, Josai International University: 1 Gumyo, Togane, Chiba 283-8555, Japan
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44
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Ortega-Becerra M, Sánchez-Moreno M, Pareja-Blanco F. Effects of Cluster Set Configuration on Mechanical Performance and Neuromuscular Activity. J Strength Cond Res 2021; 35:310-317. [PMID: 33278270 DOI: 10.1519/jsc.0000000000003907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
ABSTRACT Ortega-Becerra, M, Sánchez-Moreno, M, and Pareja-Blanco, F. Effects of cluster set configuration on mechanical performance and neuromuscular activity. J Strength Cond Res 35(2): 310-317, 2021-The aim of this study was to compare the effects of different cluster set (CS) configurations on mechanical performance and electromyography (EMG) activity during the bench press (BP) exercise. Fourteen strength-trained men (age 23.0 ± 2.4 years; height 1.76 ± 0.08 m; body mass 78.3 ± 12.2 kg) performed 3 different protocols in the BP exercise consisting of 3 sets of 12 repetitions at 60% of 1 repetition maximum with interset rests of 2 minutes, differing in the set configuration: (a) traditional sets (TRDs), (b) cluster sets of 4 repetitions (CS4), and (c) cluster sets of 2 repetitions (CS2). Intraset rests of 30 seconds were interposed for CS protocols. The mean propulsive values of force, velocity, and power output were measured for every repetition by synchronizing a linear velocity transducer with a force platform. The root mean square (RMS) and median frequency (MDF) for pectoralis major (PM) and triceps brachii (TB) muscles were also recorded for every repetition. Force, velocity, and power values progressively increased as the number of intraset rests increased (TRD < CS4 < CS2). The CS2 protocol exhibited lower RMS-PM than CS4 and TRD for almost all sets. In addition, TRDs showed significantly lower MDF-TB than CS2 for all sets and lower MDF-TB than CS4 during the third set. In conclusion, more frequent intraset rests were beneficial for maintaining mechanical performance, which may be mediated, from a neuromuscular perspective, by lesser increases in EMG amplitude and attenuated reductions in EMG frequency.
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Affiliation(s)
- Manuel Ortega-Becerra
- Physical Performance and Sports Research Center, Pablo de Olavide University, Seville, Spain
- Department of Sports and Computers Sciences, Faculty of Sport Sciences, Pablo de Olavide University, Seville, Spain ; and
| | | | - Fernando Pareja-Blanco
- Physical Performance and Sports Research Center, Pablo de Olavide University, Seville, Spain
- Department of Sports and Computers Sciences, Faculty of Sport Sciences, Pablo de Olavide University, Seville, Spain ; and
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45
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Force Steadiness during Submaximal Isometric Plantar and Dorsiflexion in Resistance Training: Experienced vs Non-experienced Individuals. CENTRAL EUROPEAN JOURNAL OF SPORT SCIENCES AND MEDICINE 2021. [DOI: 10.18276/cej.2021.2-01] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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46
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Sensitivity of the surrogate analysis method to synchronization and conduction velocity of muscular fibers. Biomed Signal Process Control 2021. [DOI: 10.1016/j.bspc.2020.102234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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47
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Amyotrophic lateral sclerosis weakens spinal recurrent inhibition and post-activation depression. Clin Neurophysiol 2020; 131:2875-2886. [DOI: 10.1016/j.clinph.2020.09.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 08/15/2020] [Accepted: 09/07/2020] [Indexed: 01/07/2023]
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48
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Schlink BR, Nordin AD, Ferris DP. Human myoelectric spatial patterns differ among lower limb muscles and locomotion speeds. Physiol Rep 2020; 8:e14652. [PMID: 33278064 PMCID: PMC7718836 DOI: 10.14814/phy2.14652] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 10/11/2020] [Accepted: 10/16/2020] [Indexed: 12/15/2022] Open
Abstract
The spatial distribution of myoelectric activity within lower limb muscles is often nonuniform and can change during different stationary tasks. Recent studies using high-density electromyography (EMG) have suggested that spatial muscle activity may also differ among muscles during locomotion, but contrasting electrode array sizes and experimental designs have limited cross-study comparisons. Here, we sought to determine if spatial EMG patterns differ among lower limb muscles and locomotion speeds. We recorded high-density EMG from the vastus medialis, tibialis anterior, biceps femoris, medial gastrocnemius, and lateral gastrocnemius muscles of 11 healthy subjects while they walked (1.2 and 1.6 m/s) and ran (2.0, 3.0, 4.0, and 5.0 m/s) on a treadmill. To overcome the detrimental effects of cable, electrode, and soft tissue movements on high-density EMG signal quality during locomotion, we applied multivariate signal cleaning methods. From these data, we computed the spatial entropy and center of gravity from the total myoelectric activity within each recording array during the stance or swing phases of the gait cycle. We found heterogeneous spatial EMG patterns evidenced by contrasting spatial entropy among lower limb muscles. As locomotion speed increased, mean entropy values decreased in four of the five recorded muscles, indicating that EMG signal amplitudes were more spatially heterogeneous, or localized, at faster speeds. The EMG center of gravity location also shifted in multiple muscles as locomotion speed increased. Contrasting myoelectric spatial distributions among muscles likely reflect differences in muscle architecture, but increasingly localized activity and spatial shifts in the center of gravity location at faster locomotion speeds could be influenced by preferential recruitment of faster motor units under greater loads.
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Affiliation(s)
- Bryan R. Schlink
- J. Crayton Pruitt Family Department of Biomedical EngineeringUniversity of FloridaGainesvilleFLUSA
| | - Andrew D. Nordin
- J. Crayton Pruitt Family Department of Biomedical EngineeringUniversity of FloridaGainesvilleFLUSA
| | - Daniel P. Ferris
- J. Crayton Pruitt Family Department of Biomedical EngineeringUniversity of FloridaGainesvilleFLUSA
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49
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Del Monte MJ, Opar DA, Timmins RG, Ross JA, Keogh JWL, Lorenzen C. Hamstring Myoelectrical Activity During Three Different Kettlebell Swing Exercises. J Strength Cond Res 2020; 34:1953-1958. [PMID: 28930870 DOI: 10.1519/jsc.0000000000002254] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Del Monte, MJ, Opar, DA, Timmins, RG, Ross, JA, Keogh, JWL, and Lorenzen, C. Hamstring myoelectrical activity during three different kettlebell swing exercises. J Strength Cond Res 34(7): 1953-1958, 2020-Kettlebell exercises have become an increasingly popular form of resistance training and component of lower-body rehabilitative training programs, despite a lack of scientific literature illustrating internal mechanisms and effectiveness of these approaches. Participants (n = 14) performed 3 different styles of kettlebell swings (hip hinge, squat, and double knee extension) and were assessed for medial hamstrings (MHs) and biceps femoris (BF) myoelectrical activity through surface electromyography (sEMG). Bipolar pregelled Ag/AgCl sEMG electrodes (10 mm diameter, 20 mm interelectrode distance) were placed on the participant's dominant limb after correct skin preparation. There was a main effect for swing type (p = 0.004), where the hip hinge swing elicited a greater overall MH and BF sEMG in comparison with the squat swing (mean difference = 3.92; 95% confidence interval [CI] = 1.53-6.32; p = 0.002) and the double knee extension swing (mean difference = 5.32; 95% CI = 0.80-9.83; p = 0.020). Across all swing types, normalized percentage of MH sEMG was significantly higher compared with the BF (mean difference = 9.93; 95% CI = 1.67-18.19; p = 0.022). The hip hinge kettlebell swing produced the greatest amount of hamstring sEMG for the 3 styles of kettlebell swings assessed. These findings have implications for the application of kettlebell swing exercises in strength and conditioning, injury prevention, and rehabilitation programs.
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Affiliation(s)
- Michael J Del Monte
- School of Exercise Science, Australian Catholic University, Melbourne, Victoria, Australia
| | - David A Opar
- School of Exercise Science, Australian Catholic University, Melbourne, Victoria, Australia
| | - Ryan G Timmins
- School of Exercise Science, Australian Catholic University, Melbourne, Victoria, Australia
| | - James A Ross
- School of Exercise Science, Australian Catholic University, Melbourne, Victoria, Australia
| | - Justin W L Keogh
- Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Queensland, Australia.,Sports Performance Research Center New Zealand, AUT University, Auckland, New Zealand; and.,Cluster for Health Improvement, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Queensland, Australia
| | - Christian Lorenzen
- School of Exercise Science, Australian Catholic University, Melbourne, Victoria, Australia
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50
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Inglis JG, Gabriel DA. Sex differences in motor unit discharge rates at maximal and submaximal levels of force output. Appl Physiol Nutr Metab 2020; 45:1197-1207. [DOI: 10.1139/apnm-2019-0958] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study evaluated potential sex differences in motor unit (MU) behaviour at maximal and submaximal force outputs. Forty-eight participants, 24 females and 24 males, performed isometric dorsiflexion contractions at 20%, 40%, 60%, 80%, and 100% of a maximum voluntary contraction (MVC). Tibialis anterior electromyography was recorded both by surface and intramuscular electrodes. Compared with males, females had a greater MU discharge rate (MUDR) averaged across all submaximal intensities (Δ 0.45 pps, 2.56%). Males exhibited greater increases in MUDR above 40% MVC, surpassing females at 100% MVC (p’s < 0.01). Averaged across all force outputs, females had a greater incidence of doublet and rapid discharges and a greater percentage of MU trains with doublet and rapid (5–10 ms) discharges (Δ 75.55% and 61.48%, respectively; p’s < 0.01). A subset of males (n = 8) and females (n = 8), matched for maximum force output, revealed that females had even greater MUDR (Δ 1.38 pps, 7.47%) and percentage of MU trains with doublet and rapid discharges (Δ 51.62%, 56.68%, respectively; p’s < 0.01) compared with males at each force output, including 100% MVC. Analysis of the subset of strength-matched males and females suggest that sex differences in MU behaviour may be a result of females needing to generate greater neural drive to achieve fused tetanus. Novelty Females had higher MUDRs and greater percentage of MU trains with doublets across submaximal force outputs (20%–80% MVC). Differences were even greater for a strength matched subset. Differences in motor unit behaviour may arise from musculoskeletal differences, requiring greater neural drive in females.
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Affiliation(s)
- J. Greig Inglis
- Electromyographic Kinesiology Laboratory, Kinesiology Department, Brock University, St. Catharines, ON L2S 3A1, Canada
- Electromyographic Kinesiology Laboratory, Kinesiology Department, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - David A. Gabriel
- Electromyographic Kinesiology Laboratory, Kinesiology Department, Brock University, St. Catharines, ON L2S 3A1, Canada
- Electromyographic Kinesiology Laboratory, Kinesiology Department, Brock University, St. Catharines, ON L2S 3A1, Canada
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