Strength training the free limb attenuates strength loss during unilateral immobilization

2009 ◽  
Vol 106 (3) ◽  
pp. 830-836 ◽  
Author(s):  
Jonathan P. Farthing ◽  
Joel R. Krentz ◽  
Charlene R. A. Magnus
Keyword(s):  
Strength Training ◽  
Muscle Activation ◽  
Muscle Thickness ◽  
Strength Loss ◽  
Peak Torque ◽  
Ulnar Deviation ◽  
Before And After ◽  
Cross Education ◽  
The Right ◽  
Arm Strength

The objective was to determine if strength training the free limb during a 3-wk period of unilateral immobilization attenuates strength loss in the immobilized limb through cross-education. Thirty right-handed participants were assigned to three groups. One group ( n = 10) wore a cast and trained the free arm (Cast-Train). A second group ( n = 10) wore a cast and did not train (Cast). A third group ( n = 10) received no treatment (control). Casts were applied to the nondominant (left) wrist and hand by a physician. Strength training was maximal isometric ulnar deviation (right hand) 5 days/wk. Peak torque (dynamometer), electromyography (EMG), and muscle thickness (ultrasound) were assessed in both arms before and after the intervention. Cast-Train improved right arm strength [14.3 (SD 5.0) to 17.7 (SD 4.8) N·m; P < 0.05] with no significant muscle hypertrophy [3.73 (SD 0.43) to 3.84 (SD 0.52) cm; P = 0.09]. The immobilized arm of Cast-Train did not change in strength [13.9 (SD 4.3) to 14.2 (SD 4.6) N·m] or muscle thickness [3.61 (SD 0.51) to 3.57 (SD 0.43) cm]. The immobilized arm of Cast decreased in strength [12.2 (SD 3.8) to 10.4 (SD 2.5) N·m; P < 0.05] and muscle thickness [3.47 (SD 0.59) to 3.32 (SD 0.55) cm; P < 0.05]. Control showed no changes in the right arm [strength: 15.3 (SD 6.1) to 14.3 (SD 5.8) N·m; muscle thickness: 3.57 (SD 0.68) to 3.52 (SD 0.75) cm] or left arm [strength: 14.5 (SD 5.3) to 13.7 (SD 6.1) N·m; muscle thickness: 3.55 (SD 0.77) to 3.51 (SD 0.70) cm]. Agonist muscle activation remained unchanged after the intervention for both arms [right: 302 (SD 188) to 314 (SD 176) μV; left: 261 (SD 139) to 288 (SD 151) μV] with no group differences. Strength training of the free limb attenuated strength loss in the immobilized limb during unilateral immobilization. Strength training may have prevented muscle atrophy in the immobilized limb.

Can Hip Joint Position affect Quadriceps Muscle Responses during Knee Extension Exercise?

2020 ◽  
Vol 41 (13) ◽  
pp. 929-935
Author(s):  
Denis César Leite Vieira ◽  
Marco Aurélio Araujo Dourado ◽  
Lucas Ugliara ◽  
Joao Luiz Quagliotti Durigan ◽  
Brad J. Schoenfeld ◽  
...  
Keyword(s):  
Vastus Lateralis ◽  
Muscle Thickness ◽  
Rectus Femoris ◽  
Peak Torque ◽  
Quadriceps Muscle ◽  
Knee Extension ◽  
Knee Extensors ◽  
Work Output ◽  
Before And After ◽  
Knee Extension Exercise

AbstractThis study investigated the acute effects of seated and supine knee extension exercise on muscle swelling, torque, and work output. Twelve resistance-trained men performed two isokinetic concentric-only knee-extension training protocols at different hip positions in a counter-balanced order. They completed the knee extension exercise in the seated (hip angle at 85°) and supine (hip angle at 180°) positions. The torque and work output were assessed during each set. Moreover, muscle thickness of the middle and proximal vastus lateralis and rectus femoris were evaluated before and after each protocol and used as an indicator of muscle swelling. Middle rectus femoris and proximal vastus lateralis thickness increased significantly (p=0.01) with no difference between exercise variations. However, the middle vastus lateralis thickness increased (p=0.01) only after the seated knee extension exercise (~7%). Knee extensors’ peak torque and work output were approximately 8% higher (p=0.04) in the seated when compared to the supine hip position. There was a similar decrease in torque and work output throughout both protocols (p=0.98). In conclusion, seated knee extension exercises produced greater torque, work output, and muscle swelling in the vastus lateralis when compared to the supine knee extension exercise.

scholarly journals Asymmetry and changes in the neuromuscular profile of short-track athletes as a result of strength training

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261265
Author(s):  
Paweł Pakosz ◽  
Anna Lukanova-Jakubowska ◽  
Edyta Łuszczki ◽  
Mariusz Gnoiński ◽  
Oscar García-García
Keyword(s):  
Strength Training ◽  
Lower Limb ◽  
Female Athletes ◽  
Lower Limbs ◽  
Lower Limb Muscles ◽  
Limb Muscles ◽  
Before And After ◽  
Monthly Period ◽  
Track Athletes ◽  
The Right

Background The purpose of this study was to identify the biomedical signals of short-track athletes by evaluating the effects of monthly strength training on changes in their neuromuscular profile, strength, and power parameters of the lower limb muscles. Muscle asymmetry, which can cause a risk of injury, was also evaluated. Methods and results This study involved female athletes, age 18.8 ± 2.7 years, with a height of 162 ± 2.4 cm, and weight of 55.9 ± 3.9 kg. Before and after the monthly preparatory period prior to the season, strength measurements were assessed through the Swift SpeedMat platform, and reactivity of the lower limb muscles was assessed with tensiomyography (TMG). The athletes were also tested before and after the recovery training period. In the test after strength training, all average countermovement jump (CMJ) results improved. Flight time showed an increase with a moderate to large effect, using both legs (5.21%). Among the TMG parameters, time contraction (Tc) changed globally with a decrease (-5.20%). Changes in the results of the test after recovery training were most often not significant. Conclusion A monthly period of strength training changes the neuromuscular profile of short-track female athletes, with no significant differences between the right and left lower limbs.

scholarly journals Effects of training, detraining, and retraining on strength, hypertrophy, and myonuclear number in human skeletal muscle

2019 ◽  
Vol 126 (6) ◽  
pp. 1636-1645 ◽  
Author(s):  
Niklas Psilander ◽  
Einar Eftestøl ◽  
Kristoffer Toldnes Cumming ◽  
Inga Juvkam ◽  
Maria M. Ekblom ◽  
...  
Keyword(s):  
Strength Training ◽  
Animal Experiments ◽  
Muscle Thickness ◽  
Fiber Volume ◽  
Cross Sectional ◽  
Leg Extension ◽  
Training Response ◽  
Before And After ◽  
Muscle Memory ◽  
Unilateral Strength Training

Previously trained mouse muscles acquire strength and volume faster than naïve muscles; it has been suggested that this is related to increased myonuclear density. The present study aimed to determine whether a previously strength-trained leg (mem-leg) would respond better to a period of strength training than a previously untrained leg (con-leg). Nine men and 10 women performed unilateral strength training (T1) for 10 wk, followed by 20 wk of detraining (DT) and a 5-wk bilateral retraining period (T2). Muscle biopsies were taken before and after each training period and analyzed for myonuclear number, fiber volume, and cross-sectional area (CSA). Ultrasound and one repetition of maximum leg extension were performed to determine muscle thickness (MT) and strength. CSA (~17%), MT (~10%), and strength (~20%) increased during T1 in the mem-leg. However, the myonuclear number and fiber volume did not change. MT and CSA returned to baseline values during DT, but strength remained elevated (~60%), supporting previous findings of a long-lasting motor learning effect. MT and strength increased similarly in the mem-leg and con-leg during T2, whereas CSA, fiber volume, and myonuclear number remained unaffected. In conclusion, training response during T2 did not differ between the mem-leg and con-leg. However, this does not discount the existence of human muscle memory, since no increase in the number of myonuclei was detected during T1 and no clear detraining effect was observed for cell size during DT; thus, the present data did not allow for a rigorous test of the muscle memory hypothesis. NEW & NOTEWORTHY If a long-lasting intramuscular memory exists in humans, this will affect strength-training advice for both athletes and the public. Based on animal experiments, we hypothesized that such a memory exists and that it is related to the myonuclear number. However, a period of unilateral strength training, followed by detraining, did not increase the myonuclear number. The training response, during a subsequent bilateral retraining period, was not enhanced in the previously trained leg.

Crossover effects of ultrasound-guided percutaneous neuromodulation on contralateral hamstring flexibility

2020 ◽  
pp. 096452842092028
Author(s):  
Blanca De-la-Cruz-Torres ◽  
Carlos Carrasco-Iglesias ◽  
Francisco Minaya-Muñoz ◽  
Carlos Romero-Morales
Keyword(s):  
Muscle Activation ◽  
Lower Limbs ◽  
Post Intervention ◽  
Crossover Effects ◽  
Hip Range Of Motion ◽  
Before And After ◽  
Hamstring Flexibility ◽  
The Right ◽  
Sliding Technique ◽  
Straight Leg Raise

Background Crossover effects refer to the responses of a non-exercised contralateral limb. There is evidence of this effect, as it relates to muscle fatigue, strength, and stretch, but not as it relates to neuromodulation. Objectives To compare the crossover effects of percutaneous neuromodulation (PNM) on hip range of motion (ROM), observed in a straight leg raise (SLR) test, in asymptomatic participants with bilateral reduced hamstring flexibility, versus the neurodynamic sciatic sliding technique, hamstring stretching and mechanical stimulation of the sciatic nerve using a needle (without electrical stimulation). To evaluate the tensiomyographic changes between the two lower limbs after these interventions. Methods 80 participants with bilateral reduced hamstring flexibility were randomized into four groups: Stretching, Neurodynamic, PNM, and Needle groups. All interventions were performed on the right limb. Each participant’s leg was subjected to SLR testing and tensiomyography before and after the interventions. Results Each group improved their SLR values in the non-intervention limb compared to baseline values, but the PNM and Needle groups obtained higher values for the SLR test in the non-intervention limb compared with the Neurodynamic and Stretching groups. There were statistically significant differences for mean SLR measures between limbs pre- and post-intervention for all groups except the PNM group, suggesting crossover effects for PNM but not the other techniques studied. There were no differences in tensiomyographic assessments between groups or between sides, at baseline or upon completion of the study. Conclusion PNM produced benefits in the SLR test in the non-intervention limb and only 1.5 min was enough to obtain this effect. In addition, no technique interfered with muscle activation.

scholarly journals Different Muscle Action Training Protocols on Quadriceps-Hamstrings Neuromuscular Adaptations

2018 ◽  
Vol 39 (05) ◽  
pp. 355-365 ◽  
Author(s):  
Cassio Ruas ◽  
Lee Brown ◽  
Camila Lima ◽  
G. Gregory Haff ◽  
Ronei Pinto
Keyword(s):  
Muscle Activation ◽  
Muscle Thickness ◽  
Muscle Quality ◽  
Muscle Size ◽  
Muscle Action ◽  
Short Term ◽  
Electromechanical Delay ◽  
Neuromuscular Adaptations ◽  
Before And After ◽  
Training Protocols

AbstractThe aim of this study was to compare three specific concentric and eccentric muscle action training protocols on quadriceps-hamstrings neuromuscular adaptations. Forty male volunteers performed 6 weeks of training (two sessions/week) of their dominant and non-dominant legs on an isokinetic dynamometer. They were randomly assigned to one of four groups; concentric quadriceps and concentric hamstrings (CON/CON, n=10), eccentric quadriceps and eccentric hamstrings (ECC/ECC, n=10), concentric quadriceps and eccentric hamstrings (CON/ECC, n=10), or no training (CTRL, n=10). Intensity of training was increased every week by decreasing the angular velocity for concentric and increasing it for eccentric groups in 30°/s increments. Volume of training was increased by adding one set every week. Dominant leg quadriceps and hamstrings muscle thickness, muscle quality, muscle activation, muscle coactivation, and electromechanical delay were tested before and after training. Results revealed that all training groups similarly increased MT of quadriceps and hamstrings compared to control (p<0.05). However, CON/ECC and ECC/ECC training elicited a greater magnitude of change. There were no significant differences between groups for all other neuromuscular variables (p>0.05). These findings suggest that different short-term muscle action isokinetic training protocols elicit similar muscle size increases in hamstrings and quadriceps, but not for other neuromuscular variables. Nevertheless, effect sizes indicate that CON/ECC and ECC/ECC may elicit the greatest magnitude of change in muscle hypertrophy.

scholarly journals Ipsilateral corticomotor responses are confined to the homologous muscle following cross-education of muscular strength

2018 ◽  
Vol 43 (1) ◽  
pp. 11-22 ◽  
Author(s):  
Joel Mason ◽  
Ashlyn K. Frazer ◽  
Deanna M. Horvath ◽  
Alan J. Pearce ◽  
Janne Avela ◽  
...  
Keyword(s):  
Strength Training ◽  
Muscular Strength ◽  
Biceps Brachii ◽  
Control Group ◽  
Elbow Flexors ◽  
Corticomotor Excitability ◽  
Flexor Carpi Radialis ◽  
Cross Education ◽  
The Right ◽  
Wrist Flexors

Cross-education of strength occurs when strength-training 1 limb increases the strength of the untrained limb and is restricted to the untrained homologous muscle. Cortical circuits located ipsilateral to the trained limb might be involved. We used transcranial magnetic stimulation (TMS) to determine the corticomotor responses from the untrained homologous (biceps brachii) and nonhomologous (flexor carpi radialis) muscle following strength-training of the right elbow flexors. Motor evoked potentials were recorded from the untrained left biceps brachii and flexor carpi radialis during a submaximal contraction from 20 individuals (10 women, 10 men; aged 18–35 years; training group, n = 10; control group, n = 10) before and after 3 weeks of strength-training the right biceps brachii at 80% of 1-repetition maximum. Recruitment-curves for corticomotor excitability and inhibition of the untrained homologous and nonhomologous muscle were constructed and assessed by examining the area under the recruitment curve. Strength-training increased strength of the trained elbow flexors (29%), resulting in an 18% increase in contralateral strength of the untrained elbow flexors (P < 0.0001). The trained wrist flexors increased by 19%, resulting in a 12% increase in strength of the untrained wrist flexors (P = 0.005). TMS showed increased corticomotor excitability and decreased corticomotor inhibition for the untrained homologous muscle (P < 0.05); however, there were no changes in the untrained nonhomologous muscle (P > 0.05). These findings show that the cross-education of muscular strength is spatially distributed; however, the neural adaptations are confined to the motor pathway ipsilateral to the untrained homologous agonist.

Effect of strength training combined with antioxidant supplementation on muscular performance

2018 ◽  
Vol 43 (8) ◽  
pp. 775-781 ◽  
Author(s):  
Maurilio T. Dutra ◽  
Sávio Alex ◽  
Marcio Rabelo Mota ◽  
Nathalia B. Sales ◽  
Lee E. Brown ◽  
...  
Keyword(s):  
Strength Training ◽  
Randomized Study ◽  
Muscle Thickness ◽  
Peak Torque ◽  
Quadriceps Muscle ◽  
Muscle Performance ◽  
Control Group ◽  
Total Work ◽  
Antioxidant Supplementation ◽  
Significant Group

This was a placebo-controlled randomized study that aimed to investigate the effects of strength training (ST) combined with antioxidant supplementation on muscle performance and thickness. Forty-two women (age, 23.8 ± 2.7 years; body mass, 58.7 ± 11.0 kg; height, 1.63 ± 0.1 m) were allocated into 3 groups: vitamins (n = 15), placebo (n = 12), or control (n = 15). The vitamins and placebo groups underwent an ST program, twice a week, for 10 weeks. The vitamins group was supplemented with vitamins C (1 g/day) and E (400 IU/day) during the ST period. Before and after training, peak torque (PT) and total work (TW) were measured on an isokinetic dynamometer, and quadriceps muscle thickness (MT) was assessed by ultrasound. Mixed-factor ANOVA was used to analyze data and showed a significant group × time interaction for PT and TW. Both the vitamins (37.2 ± 5.4 to 40.3 ± 5.6 mm) and placebo (39.7 ± 5.2 to 42.5 ± 5.6 mm) groups increased MT after the intervention (P < 0.05) with no difference between them. The vitamins (146.0 ± 29.1 to 170.1 ± 30.3 N·m) and placebo (158.9 ± 22.4 to 182.7 ± 23.2 N·m) groups increased PT after training (P < 0.05) and PT was higher in the placebo compared with the control group (P = 0.01). The vitamins (2068.3 ± 401.2 to 2295.5 ± 426.8 J) and placebo (2165.1 ± 369.5 to 2480.8 ± 241.3 J) groups increased TW after training (P < 0.05) and TW was higher in the placebo compared with the control group (P = 0.01). Thus, chronic antioxidant supplementation may attenuate peak torque and total work improvement in young women after 10 weeks of ST.

scholarly journals Potentiation and Electrical Stimulus Frequency During Self-Paced Exercise and Recovery

2014 ◽  
Vol 42 (1) ◽  
pp. 91-101 ◽  
Author(s):  
Christian Froyd ◽  
Fernando G. Beltrami ◽  
Jørgen Jensen ◽  
Guillaume Y. Millet ◽  
Timothy David Noakes
Keyword(s):  
Stimulus Frequency ◽  
Time Trial ◽  
Peak Torque ◽  
Electrical Stimulus ◽  
Voluntary Contraction ◽  
Peripheral Fatigue ◽  
Paired Stimuli ◽  
Torque Measurements ◽  
Before And After ◽  
The Right

Abstract The aim of this study was to investigate the effect of potentiation on stimulation-induced muscle function during and after an intense bout of self-paced dynamic exercise. Ten active subjects performed a time trial involving repetitive concentric extension-flexion of the right knee using a Biodex dynamometer. Electrical stimulation before and after a 5 s maximal isometric voluntary contraction was performed before the start of the time trial and immediately (< 5 s) after each 20% of the time trial as well as 1, 2, 4 and 8 min after time trial termination. Potentiation was observed before the time trial and as early as 1-2 min after the time trial, but no potentiation was detected during or immediately after the time trial for neither single or paired stimuli. At termination of the time trial, “potentiated” peak torque was significantly more reduced than “unpotentiated" peak torque for single stimulus (-65 ± 10% and -42 ± 18%, respectively) and paired stimuli at 100 Hz (-51 ± 10% and -33 ± 15%, respectively). Faster recovery for “potentiated” compared to “unpotentiated” peak torque indicate that potentiate peak torque measurements or delay the post-exercise measurements more than a few seconds, will underestimate peripheral fatigue. In conclusion, the potentiation after maximal contraction disappears during intense exercise. Whether the muscle is already potentiated during intense contraction or fatiguing mechanisms inhibits potentiation remains to be clarified

scholarly journals The Effects of Whole-Body Vibration on the Cross-Transfer of Strength

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Alicia M. Goodwill ◽  
Dawson J. Kidgell
Keyword(s):  
Strength Training ◽  
Whole Body Vibration ◽  
Peak Height ◽  
Whole Body ◽  
Control Group ◽  
Body Vibration ◽  
Training Groups ◽  
Cross Education ◽  
The Cross ◽  
The Right

This study investigated whether the use of superimposed whole-body vibration (WBV) during cross-education strength training would optimise strength transfer compared to conventional cross-education strength training. Twenty-one healthy, dominant right leg volunteers (21±3years) were allocated to a strength training (ST,m=3,f=4), a strength training with WBV (ST + V,m=3,f=4), or a control group (no training,m=3,f=4). Training groups performed 9 sessions over 3 weeks, involving unilateral squats for the right leg, with or without WBV (35 Hz; 2.5 mm amplitude). All groups underwent dynamic single leg maximum strength testing (1RM) and single and paired pulse transcranial magnetic stimulation (TMS) prior to and following training. Strength increased in the trained limb for the ST (41%;ES=1.14) and ST + V (55%;ES=1.03) groups, which resulted in a 35% (ES=0.99) strength transfer to the untrained left leg for the ST group and a 52% (ES=0.97) strength transfer to the untrained leg for the ST + V group, when compared to the control group. No differences in strength transfer between training groups were observed(P=0.15). For the untrained leg, no differences in the peak height of recruitment curves or SICI were observed between ST and ST + V groups(P=1.00). Strength training with WBV does not appear to modulate the cross-transfer of strength to a greater magnitude when compared to conventional cross-education strength training.

scholarly journals Effect of Acute Static Stretching on the Activation Patterns Using High-Density Surface Electromyography of the Gastrocnemius Muscle during Ramp-Up Task

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4841
Author(s):  
Noriaki Maeda ◽  
Makoto Komiya ◽  
Yuichi Nishikawa ◽  
Masanori Morikawa ◽  
Shogo Tsutsumi ◽  
...  
Keyword(s):  
Motor Unit ◽  
Muscle Activation ◽  
Gastrocnemius Muscle ◽  
Peak Torque ◽  
Voluntary Contraction ◽  
Motor Unit Recruitment ◽  
Static Stretching ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Before And After

This study aimed to evaluate motor unit recruitment during submaximal voluntary ramp contraction in the medial head of the gastrocnemius muscle (MG) by high-density spatial electromyography (SEMG) before and after static stretching (SS) in healthy young adults. SS for gastrocnemius was performed in 15 healthy participants for 2 min. Normalized peak torque by bodyweight of the plantar flexor, muscle activity at peak torque, and muscle activation patterns during ramp-up task were evaluated before and after SS. Motor unit recruitment during the submaximal voluntary contraction of the MG was measured using SEMG when performing submaximal ramp contractions during isometric ankle plantar flexion from 30 to 80% of the maximum voluntary contraction (MVC). To evaluate the changes in the potential distribution of SEMG, the root mean square (RMS), modified entropy, and coefficient of variation (CV) were calculated from the dense surface EMG data when 10% of the MVC force was applied. Muscle activation patterns during the 30 to 80% of MVC submaximal voluntary contraction tasks were significantly changed from 50 to 70% of MVC after SS when compared to before. The variations in motor unit recruitment after SS indicate diverse motor unit recruitments and inhomogeneous muscle activities, which may adversely affect the performance of sports activities.

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