Corticomotor plasticity following unilateral strength training

• Published in: Muscle & nerve Vol. 46; no. 3; pp. 384 - 393
• Main Authors: Goodwill, Alicia M., Pearce, Alan J., Kidgell, Dawson J.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01-09-2012; Wiley
• Subjects: Adaptation, Physiological - physiology; Adolescent; Adult; Biological and medical sciences; cross education; Electromyography; Evoked Potentials, Motor - physiology; Female; Functional Laterality - physiology; Fundamental and applied biological sciences. Psychology; Humans; intracortical inhibition; Leg - physiology; Male; Motor Cortex - physiology; Muscle Strength - physiology; Muscle, Skeletal - physiology; Neuronal Plasticity - physiology; Neurons - physiology; primary motor cortex; Resistance Training; strength training; Striated muscle. Tendons; Transcranial Magnetic Stimulation; Vertebrates: osteoarticular system, musculoskeletal system; Human; strength training; Transcranial magnetic stimulation; Motor pathway; Central nervous system; intracortical inhibition; Electrophysiology; Excitability; Lower limb; Encephalon; Recruitment; Motor cortex; Plasticity; cross education; Motor evoked potential; Strength; Adaptation; primary motor cortex
• ISSN: 0148-639X; 1097-4598
• DOI: 10.1002/mus.23316

Introduction: We used transcranial magnetic stimulation (TMS) to investigate 3 weeks of unilateral leg strength training on ipsilateral motor cortex (iM1) excitability, and short‐latency intracortical inhibition (SICI). Methods: Right leg dominant participants (n = 14) were randomly divided into either a strength training (ST) or control group. The ST group completed 9 training sessions (4 sets of 6 to 8 repetitions of single right leg squats). Results: We observed a 41% increase in right leg strength, and a 35% increase in strength of the untrained left leg (P < 0.01). There was a significant increase in motor evoked potential (MEP) amplitude recruitment curve for the untrained left leg (P < 0.01). SICI of the iM1 decreased by 21% for the untrained left leg (P < 0.01). Conclusions: The findings provide evidence for corticomotor adaptation for unilateral leg strength training within the iM1 that is modulated by changes in interhemispheric inhibition. Muscle Nerve 46: 384–393, 2012