Angle-specific impairment of elbow flexors strength after isometric exercise at long muscle length

The aim of the study was to determine the effect of different muscle length and visual feedback information (VFI) on accuracy of isometric contraction of elbow flexors in men after an ischemic stroke (IS).Materials and Methods. Maximum voluntary muscle contraction force (MVMCF) and accurate determinate muscle force (20% of MVMCF) developed during an isometric contraction of elbow flexors in 90° and 60° of elbow flexion were measured by an isokinetic dynamometer in healthy subjects (MH,n=20) and subjects after an IS during their postrehabilitation period (MS,n=20).Results. In order to evaluate the accuracy of the isometric contraction of the elbow flexors absolute errors were calculated. The absolute errors provided information about the difference between determinate and achieved muscle force.Conclusions. There is a tendency that greater absolute errors generating determinate force are made by MH and MS subjects in case of a greater elbow flexors length despite presence of VFI. Absolute errors also increase in both groups in case of a greater elbow flexors length without VFI. MS subjects make greater absolute errors generating determinate force without VFI in comparison with MH in shorter elbow flexors length.

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Isotonic muscle function is selectively reduced after muscle damage induced by isometric exercise at a long muscle length

Isokinetics and Exercise Science ◽

10.3233/ies-2007-0252 ◽

2007 ◽

Vol 15 (2) ◽

pp. 69-75 ◽

Cited By ~ 4

Author(s):

A. Philippou ◽

G.C. Bogdanis ◽

M. Maridaki

Keyword(s):

Muscle Damage ◽

Muscle Function ◽

Isometric Exercise ◽

Muscle Length

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Muscle fatigue and pain after eccentric contractions at long and short length

Clinical Science ◽

10.1042/cs0740553 ◽

1988 ◽

Vol 74 (5) ◽

pp. 553-557 ◽

Cited By ~ 76

Author(s):

D. J. Newham ◽

D. A. Jones ◽

G. Ghosh ◽

P. Aurora

Keyword(s):

Muscle Strength ◽

Muscle Pain ◽

Muscle Length ◽

Short Length ◽

Eccentric Contractions ◽

Elbow Flexors ◽

Muscle Tenderness ◽

Dependent Component ◽

Force Characteristics ◽

Contralateral Muscle

1. The effect of muscle length on the development of muscle pain and fatigue has been studied. 2. Eight normal young adults performed maximal eccentric contractions of the elbow flexors. The muscles of one arm were exercised at short length, and the contralateral muscle at long length. Each contraction lasted approximately 1 s, and was repeated once every 10 s for 30 min. 3. Muscle strength and frequency-force characteristics were measured from isometric contractions before, immediately after and at 24 h intervals for the next 4 days. Muscle tenderness was assessed daily. 4. The muscle strength was reduced by approximately 10% by exercise at short length, and by 30% by exercise at long length. 5. The 20:100 ratio (force generated by stimulation at 20 Hz/force generated at 100 Hz) fell by 30% after exercise at short length and had recovered after 24 h. Exercise at long length reduced this ratio by 65% and the muscles had not fully recovered 4 days later. 6. Muscle pain developed after both exercise regimens, but was slightly worse after that at long length. 7. It is concluded that there is a length-dependent component in the development of pain and fatigue after eccentric exercise, which had previously been thought to be caused solely by high force generation.

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Does Performing Different Resistance Exercises for the Same Muscle Group Induce Non-homogeneous Hypertrophy?

International Journal of Sports Medicine ◽

10.1055/a-1308-3674 ◽

2021 ◽

Author(s):

Bruna Daniella de Vasconcelos Costa ◽

Witalo Kassiano ◽

João Pedro Nunes ◽

Gabriel Kunevaliki ◽

Pâmela Castro-E-Souza ◽

...

Keyword(s):

Muscle Length ◽

Muscle Thickness ◽

Relative Increase ◽

Muscle Group ◽

Elbow Flexors ◽

Proximal Site ◽

Resistance Exercises ◽

Elbow Flexors And Extensors ◽

Lateral Thigh ◽

Muscle Groups

AbstractThe study aimed to compare the effect of performing the same or different exercises for a muscle group on resistance training (RT) sessions on muscle hypertrophy at different sites along muscle length. Twenty-two detrained men (23.3±4.1 years) were randomly allocated to the following groups: a group that performed the same exercises in all training sessions (N-VAR=11) or one that varied the exercises for the same muscle groups (VAR=11). All were submitted to 3 weekly sessions for nine weeks. Muscle thickness was assessed at the proximal, middle, and distal sites of the lateral and anterior thigh, elbow flexors, and extensors by B-mode ultrasound. The VAR group significantly increased all the sites analyzed (P<0.05). Furthermore, the proximal site of the lateral thigh showed a larger relative increase when compared to the middle site (P<0.05). In contrast, the N-VAR group were not revealed significant improvements only for the middle site of the lateral thigh and the proximal site of the elbow flexors (P>0.05). Our results suggest that to perform different resistance exercises can induce hypertrophy of all sites assessed in detrained young men.

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Two maximal isometric contractions attenuate the magnitude of eccentric exercise-induced muscle damage

Applied Physiology Nutrition and Metabolism ◽

10.1139/h2012-035 ◽

2012 ◽

Vol 37 (4) ◽

pp. 680-689 ◽

Cited By ~ 24

Author(s):

Hsin-Lian Chen ◽

Kazunori Nosaka ◽

Alan J. Pearce ◽

Trevor C. Chen

Keyword(s):

Muscle Damage ◽

Eccentric Exercise ◽

Muscle Soreness ◽

Muscle Length ◽

Peak Torque ◽

Eccentric Contractions ◽

Control Group ◽

Isometric Contractions ◽

Elbow Flexors ◽

Exercise Induced

This study investigated whether maximal voluntary isometric contractions (MVC-ISO) would attenuate the magnitude of eccentric exercise-induced muscle damage. Young untrained men were placed into one of the two experimental groups or one control group (n = 13 per group). Subjects in the experimental groups performed either two or 10 MVC-ISO of the elbow flexors at a long muscle length (20° flexion) 2 days prior to 30 maximal isokinetic eccentric contractions of the elbow flexors. Subjects in the control group performed the eccentric contractions without MVC-ISO. No significant changes in maximal voluntary concentric contraction peak torque, peak torque angle, range of motion, upper arm circumference, plasma creatine kinase (CK) activity and myoglobin concentration, muscle soreness, and ultrasound echo intensity were evident after MVC-ISO. Changes in the variables following eccentric contractions were smaller (P < 0.05) for the 2 MVC-ISO group (e.g., peak torque loss at 5 days after exercise, 23% ± 3%; peak CK activity, 1964 ± 452 IU·L–1; peak muscle soreness, 46 ± 4 mm) or the 10 MVC-ISO group (13% ± 3%, 877 ± 198 IU·L–1, 30 ± 4 mm) compared with the control (34% ± 4%, 6192 ± 1747 IU·L–1, 66 ± 5 mm). The 10 MVC-ISO group showed smaller (P < 0.05) changes in all variables following eccentric contractions compared with the 2 MVC-ISO group. Therefore, two MVC-ISO conferred potent protective effects against muscle damage, whereas greater protective effect was induced by 10 MVC-ISO, which can be used as a strategy to minimize muscle damage.

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Muscle damage produced by isometric contractions in human elbow flexors

Journal of Applied Physiology ◽

10.1152/japplphysiol.00535.2017 ◽

2018 ◽

Vol 124 (2) ◽

pp. 388-399 ◽

Cited By ~ 8

Author(s):

Trevor J. Allen ◽

Tyson Jones ◽

Anthony Tsay ◽

David L. Morgan ◽

Uwe Proske

Keyword(s):

Muscle Damage ◽

Muscle Soreness ◽

Isometric Exercise ◽

Isometric Contractions ◽

Elbow Flexors ◽

Disuse Atrophy ◽

Half Maximum ◽

Maximum Effort ◽

Damage Process ◽

Voluntary Contractions

Isometric exercise is often prescribed during rehabilitation from injury to maintain muscle condition and prevent disuse atrophy. However, such exercise can lead to muscle soreness and damage. Here we investigate which parameters of isometric contractions are responsible for the damage. Bouts of 30 repetitions of maximum voluntary contractions of elbow flexors in 38 subjects were carried out and peak force, soreness, and tenderness were measured before the exercise, immediately afterwards, at 2 h, and at 24 h postexercise. When one arm was held near the optimum angle for force generation (90°), the force it produced was greater by 28% than by the other arm held at a longer length (155°). However, despite the smaller contraction forces of the muscle held at the longer length, after the exercise it exhibited a greater fall in force that persisted out to 24 h (20% fall) and more delayed soreness than the muscle exercised at 90° (7% fall at 24 h). The result indicates a length dependence of the damage process for isometric contractions at maximum effort. In four additional experiments, evidence was provided that the damage occurred during the plateau of the contraction and not the rising or relaxation phases. The damage had a prompt onset and was cumulative, continuing for the duration of the contraction. We interpret our findings in terms of the nonuniform lengthening of sarcomeres during the plateau of the contractions and conclude that muscle damage from isometric exercise is minimized if carried out at lengths below the optimum, using half-maximum or smaller contractions. NEW & NOTEWORTHY Isometric exercise, where muscle contracts while the limb is held fixed, is often possible for individuals rehabilitating from injury and can help maintain muscle condition. Such exercise has been reported to cause some muscle damage and soreness. We confirm this and show that to minimize damage, exercising muscles should be held at shorter than the optimum length for force and carried out at half-maximum effort or less.

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Morphological Basis of the Disparity Between Muscle Length and Sarcomere Length in the Myocardium

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100072551 ◽

1973 ◽

Vol 31 ◽

pp. 422-423

Author(s):

G.E. Adomian ◽

L. Chuck ◽

W.W. Pannley

Keyword(s):

Cardiac Muscle ◽

Sarcomere Length ◽

Muscle Length ◽

Contractile Force ◽

Direct Function ◽

Morphological Basis ◽

Tension Curve

Sonnenblick, et al, have shown that sarcomeres change length as a function of cardiac muscle length along the ascending portion of the length-tension curve. This allows the contractile force to be expressed as a direct function of sarcomere length. Below L max, muscle length is directly related to sarcomere length at lengths greater than 85% of optimum. However, beyond the apex of the tension-length curve, i.e. L max, a disparity occurs between cardiac muscle length and sarcomere length. To account for this disproportionate increase in muscle length as sarcomere length remains relatively stable, the concept of fiber slippage was suggested as a plausible explanation. These observations have subsequently been extended to the intact ventricle.

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