scholarly journals The effect of unilateral training on contralateral limb strength in young, older, and patient populations: a meta-analysis of cross education

2018 ◽  
Vol 23 (4-5) ◽  
pp. 238-249 ◽  
Author(s):  
Lara A. Green ◽  
David A. Gabriel
Keyword(s):  
Meta Analysis ◽  
Contralateral Limb ◽  
Cross Education ◽  
Unilateral Training

scholarly journals Lower extremity reamputation in people with diabetes: a systematic review and meta-analysis

2021 ◽  
Vol 9 (1) ◽  
pp. e002325
Author(s):  
Rongqi Liu ◽  
Brian J Petersen ◽  
Gary M Rothenberg ◽  
David G Armstrong
Keyword(s):  
Lower Extremity ◽  
Temporal Trend ◽  
Meta Analysis ◽  
Kendall Test ◽  
Incidence Rates ◽  
Contralateral Limb ◽  
Free Survival ◽  
Patients With Diabetes ◽  
Parametric Survival ◽  
Qualitative Characteristics

In this study, we determined the reamputation-free survival to both limbs and to the contralateral limb only following an index amputation of any-level and assessed whether reamputation rates have changed over time. We completed a systematic search using PubMed and screened a total of 205 articles for data on reamputation rates. We reported qualitative characteristics of 56 studies that included data on reamputation rates and completed a meta-analysis on 22 of the studies which enrolled exclusively participants with diabetes. The random-effects meta-analysis fit a parametric survival distribution to the data for reamputations to both limbs and to the contralateral limb only. We assessed whether there was a temporal trend in the reamputation rate using the Mann-Kendall test. Incidence rates were high for reamputation to both limbs and to the contralateral limb only. At 1 year, the reamputation rate for all contralateral and ipsilateral reamputations was found to be 19% (IQR=5.1%–31.6%), and at 5 years, it was found to be 37.1% (IQR=27.0%–47.2%). The contralateral reamputation rate at 5 years was found to be 20.5% (IQR=13.3%–27.2%). We found no evidence of a trend in the reamputation rates over more than two decades of literature analyzed. The incidence of lower extremity reamputation is high among patients with diabetes who have undergone initial amputations secondary to diabetes, and rates of reamputation have not changed over at least two decades.

Contralateral effects of unilateral resistance training: a meta-analysis

2004 ◽  
Vol 96 (5) ◽  
pp. 1861-1866 ◽  
Author(s):  
J. Munn ◽  
R. D. Herbert ◽  
S. C. Gandevia
Keyword(s):  
Resistance Training ◽  
Confidence Interval ◽  
Strength Training ◽  
Meta Analysis ◽  
Contralateral Limb ◽  
Initial Strength ◽  
Randomized Controlled Studies ◽  
And Control ◽  
Voluntary Strength ◽  
Contralateral Effects

It is often claimed that strength training of one limb increases the strength of the contralateral limb, but this has not been demonstrated consistently, particularly in well-controlled studies. The aim was to quantitatively combine the results of other studies on the effects of unilateral training on contralateral strength in humans to provide an answer to this physiological question. We analyzed all randomized controlled studies of voluntary unilateral resistance training that used training intensities of at least 50% of maximal voluntary strength for a minimum of 2 wk. Studies were identified by computerized and hand searches of the literature. Data on changes in strength of contralateral and control limbs were extracted and statistically pooled in a meta-analysis. This approach allows conclusions to be based on a statistically meaningful sample size, which might be difficult to achieve in other ways. Seventeen studies met the inclusion criteria, and 13 provided enough data for statistical pooling. The contralateral effects of strength training reported in individual studies varied from -2.7 to 21.6% of initial strength. The pooled estimate of the effect of unilateral resistance training on the maximal voluntary strength of the contralateral limb was 7.8% (95% confidence interval: 4.1-11.6%). This was 35.1% (95% confidence interval: 20.9-49.3%) of the effect on the trained limb. Pooling of all available data shows that unilateral strength training produces modest increases in contralateral strength.

Effects of Cross-Education After 6 Weeks of Eccentric Single-Leg Decline Squats Performed With Different Execution Times: A Randomized Controlled Trial

2021 ◽  
pp. 194173812110163
Author(s):  
Fernando Martínez ◽  
Pablo Abián ◽  
Fernando Jiménez ◽  
Javier Abián-Vicén
Keyword(s):  
Randomized Controlled Trial ◽  
Controlled Trial ◽  
Knee Extensor ◽  
Eccentric Contraction ◽  
Contractile Properties ◽  
Eccentric Training ◽  
Contralateral Limb ◽  
Randomized Controlled ◽  
Cross Education ◽  
Experimental Group

Background: Cross-education of strength refers to the strength gain that is transferred to the contralateral limb after a unilateral training program. Hypothesis: Unilateral eccentric training using different muscle contraction times would improve the structural and functional properties of the untrained contralateral limb. Study Design: Randomized controlled trial. Level of Evidence: Level 2. Methods: Thirty-six participants were randomized into a control group, experimental group 1 (EG6s; eccentric contraction runtime = 6 seconds) and experimental group 2 (EG3s; eccentric contraction runtime = 3 seconds). The thickness and elastographic index of the patellar tendon (PT), lean mass and fat percentage of the thigh, contractile properties of the vastus lateralis (VL), as well as isometric, concentric, and eccentric knee extensor peak torques, and eccentric single-leg decline squat (SLDSe) 1 repetition maximum (1-RM) were measured after 6 weeks of SLDSe training (3 times per week, 80% of 1-RM) and after 6 weeks of detraining in the untrained contralateral limb. Results: After training, there was an increase in lean thigh mass of the untrained limb in both groups: EG6s (0.17 ± 0.29 kg; P = 0.03; effect size [ES] = 0.15) and EG3s (0.15 ± 0.23 kg; P = 0.04; ES = 0.19). Likewise, both EG6s (62.30 ± 19.09 kg; P < 0.001; ES = 4.23) and EG3s (68.09 ± 27.49 kg; P < 0.001; ES = 3.40) increased their 1-RM, isometric (EG6s: 48.64 ± 44.82 N·m, P < 0.001, ES = 0.63; EG3s: 34.81 ± 47.30 N·m, P = 0.004, ES = 0.38), concentric at 60 deg/s and 180 deg/s and eccentric at 60 deg/s and 180 deg/s knee extensor peak torques ( P < 0.05) in the untrained limb. However, no differences were found in the contractile properties of the VL or in the thickness of the PT after eccentric training in either of the 2 experimental groups. Conclusion: Regardless of the runtime of the contraction, 6 weeks of SLSDe was effective for inducing structural and strength adaptations in the contralateral untrained limb. However, most of these adaptations were lost after 6 weeks of detraining. Clinical Relevance: Our study suggests that cross-education training can be of great importance for clinical application and musculoskeletal and neuromuscular rehabilitative processes after unilateral injury.

scholarly journals The cross education of strength and skill following unilateral strength training in the upper and lower limbs

2018 ◽  
Vol 120 (2) ◽  
pp. 468-479 ◽  
Author(s):  
Lara A. Green ◽  
David A. Gabriel
Keyword(s):  
Motor Learning ◽  
Strength Training ◽  
Training Program ◽  
Lower Limbs ◽  
Force Variability ◽  
Wrist Flexion ◽  
Cross Education ◽  
Highly Correlated ◽  
V Wave ◽  
Unilateral Training

Cross education is the strength gain or skill improvement transferred to the contralateral limb following unilateral training or practice. The present study examined the transfer of both strength and skill following a strength training program. Forty participants (20M, 20F) completed a 6-wk unilateral training program of dominant wrist flexion or dorsiflexion. Strength, force variability, and muscle activity were assessed pretraining, posttraining, and following 6 wk of detraining (retention). Analyses of covariance compared the experimental limb (trained or untrained) to the control (dominant or nondominant). There were no sex differences in the training response. Cross education of strength at posttraining was 6% ( P < 0.01) in the untrained arm and 13% ( P < 0.01) in the untrained leg. Contralateral strength continued to increase following detraining to 15% in the arm ( P < 0.01) and 14% in the leg ( P < 0.01). There was no difference in strength gains between upper and lower limbs ( P > 0.05). Cross education of skill (force variability) demonstrated greater improvements in the untrained limbs compared with the control limbs during contractions performed without concurrent feedback. Significant increases in V-wave amplitude ( P = 0.02) and central activation ( P < 0.01) were highly correlated with contralateral strength gains. There was no change in agonist amplitude or motor unit firing rates in the untrained limbs ( P > 0.05). The neuromuscular mechanisms mirrored the force increases at posttraining and retention supporting central drive adaptations of cross education. The continued strength increases at retention identified the presence of motor learning in cross education, as confirmed by force variability. NEW & NOTEWORTHY: We examined cross education of strength and skill following 6 wk of unilateral training and 6 wk of detraining. A novel finding was the continued increase in contralateral strength following both training and detraining. Neuromuscular adaptations were highly correlated with strength gains in the trained and contralateral limbs. Motor learning was evident in the trained and contralateral limbs during contractions performed without concurrent feedback.

scholarly journals Evidence of homologous and heterologous effects after unilateral leg training in youth

2018 ◽  
Vol 43 (3) ◽  
pp. 282-291 ◽  
Author(s):  
Aymen Ben Othman ◽  
David G. Behm ◽  
Anis Chaouachi
Keyword(s):  
Handgrip Strength ◽  
High Load ◽  
Upper Body ◽  
Knee Extensors ◽  
Leg Press ◽  
Positive Effects ◽  
Low Load ◽  
Cross Education ◽  
Education Effects ◽  
Unilateral Training

The positive effects of unilateral training on contralateral muscles (cross education) has been demonstrated with adults for over a century. There is limited evidence for cross education of heterologous muscles. Cross education has not been demonstrated with children. It was the objective of this study to investigate cross-education training in children examining ipsilateral and contralateral homologous and heterologous muscles. Forty-eight male children (aged 10–13 years) were assessed for unilateral, ipsilateral and contralateral lower limb strength, power and endurance (1-repetition maximum (RM) leg press, knee extensors (KE) and flexors (KF) maximum voluntary isometric contractions (MVIC), countermovement jump, muscle endurance test (leg press repetitions with 60% 1RM)), and upper body unilateral MVIC elbow flexors (EF) and handgrip strength. An 8-week training program involved 2 unilateral leg press resistance-training groups (high load/low repetitions: 4–8 sets of 5RM, and low load/high repetitions: 1–2 sets of 20RM) and control (untrained) group. All muscles exhibited improvements of 6.1% to 89.1%. The trained limb exhibited greater adaptations than the untrained limb for leg press 1RM (40.3% vs. 25.2%; p = 0.005), and 60% 1RM leg press (104.1% vs. 73.4%; p = 0.0001). The high load/low repetition training induced (p < 0.0001) greater improvements than low load/high repetition with KE, KF, EF MVIC and leg press 1RM. This is the first study to demonstrate cross-education effects with children and that the effects of unilateral training involve both contralateral homologous and heterologous muscles with the greatest strength-training responses from high-load/low-repetition training.

Determining the Effects of Cross-Education on Muscle Strength, Thickness and Cortical Activation Following Limb Immobilization: A Systematic Review and Meta-Analysis

2020 ◽  
Vol 2 (4) ◽  
pp. 1-19
Author(s):  
Madelaine Haggert ◽  
Alan Pearce ◽  
Ashlyn Frazer ◽  
Simin Rahman ◽  
Dawson Kidgell ◽  
...  
Keyword(s):  
Systematic Review ◽  
Muscle Strength ◽  
Muscle Activation ◽  
Meta Analysis ◽  
Muscle Thickness ◽  
Cortical Activation ◽  
Neural Activation ◽  
Cortical Level ◽  
Cross Education ◽  
Limb Immobilization

Purpose: Cross-education (CE) increases strength of both the trained and untrained limb, with emerging evidence, suggesting CE could be used to attenuate muscle strength and thickness following periods of limb immobilization. This study examined the available evidence for the clinical efficacy of CE to attenuate muscle strength, thickness and neural activation during limb immobilization. Methods: We performed a systematic review and meta-analysis on the effects of CE on muscle strength, thickness and activation of an immobilized limb.  The evidence from randomized controlled trials (RCTs) were pooled to assess effect estimates for changes in strength, muscle thickness and neural activation of the untrained immobilized limb. Results: CE attenuated muscle strength in 5 RCTs (n= 78) which reported a SMD of 1.60 (95% CI 0.62, 2.59; P = 0.001) and muscle thickness, with an SMD of 1.52 (95% CI 0.22, 2.81; P = 0.02) compared to control. There was no difference in muscle activation (SMD of 0.08; 95% CI -0.34, 0.50; P = 0.72), regions of cortical activation (MD 31.8; 95% CI -22.71, 86.31; P = 0.25) or corticospinal excitability (MD 5.2; 95% CI -2.38, 12.78; P = 0.18) compared to control.    Conclusions: These results show that strength training the free limb via cross-education maintains muscle strength and muscle thickness of the immobilized limb compared to control (immobilization only). Because there was no effect on muscle activation, but a large mean difference in cortical activation, it is likely that the attenuation of muscle strength is due to neural adaptations at a cortical level.

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