Unilateral strength training increases voluntary activation of the opposite untrained limb.
- PubMed: 19230754
Abstract
OBJECTIVE: We investigated whether an increase in neural drive from the motor cortex contributes to the cross-limb transfer of strength that can occur after unilateral strength training. METHODS: Twitch interpolation was performed with transcranial magnetic stimulation to assess changes in strength and cortical voluntary activation in the untrained left wrist, before and after 4 weeks of unilateral strength-training involving maximal voluntary isometric wrist extension contractions (MVCs) for the right wrist (n=10, control group=10). RESULTS: Wrist extension MVC force increased in both the trained (31.5+/-18%, mean+/-SD, p<0.001) and untrained wrist (8.2+/-9.7%, p=0.02), whereas wrist abduction MVC did not change significantly. The amplitude of the superimposed twitches evoked during extension MVCs decreased by 35% (+/-20%, p<0.01), which contributed to a significant increase in voluntary activation (2.9+/-3.5%, p<0.01). Electromyographic responses to cortical and peripheral stimulation were unchanged by training. There were no significant changes for the control group which did not train. CONCLUSION: Unilateral strength training increased the capacity of the motor cortex to drive the homologous untrained muscles. SIGNIFICANCE: The data show for the first time that an increase in cortical drive contributes to the contralateral strength training effect.
Sign up today - FREE
Mendeley saves you time finding and organizing research. Learn more
- All your research in one place
- Add and import papers easily
- Access it anywhere, anytime
Start using Mendeley in seconds!
Readership Statistics
Groups
 |