Acute exercise after motor practice enhances generalized skill learning, corticospinal excitability and intermuscular coherence in older adults

While high-intensity aerobic exercise after motor practice enhances learning in young adults, its effects on older adults remain unknown. This study investigates whether high-intensity exercise after motor skill practice enhances memory consolidation and motor learning in older adults (aged 65-75 years). Participants practiced a visuomotor-pinch-task with repeated sequence-structure, before being randomly assigned to an exercise (EXE, n = 20) or control (CON, n = 20) group. Motor performance was assessed at baseline, immediately after practice, and in delayed retention tests performed 24-hours and 7-days later. Performance was also assessed in a task variant with random target-structure at immediate and delayed retention. Electromyography was recorded from first dorsal interosseous and abductor pollicis brevis muscles, for intermuscular coherence analysis. Corticospinal and cortical excitability was assessed by single and paired-pulse transcranial magnetic stimulation of the primary motor cortex at baseline, after practice, and again after the EXE or CON intervention. No between-group differences were observed during skill acquisition (before randomization). From immediate to delayed retention tests (24-hours and 7-days) EXE showed higher retention in the random target-structure variant compared to CON, while no differences were observed in the sequential task. Both groups demonstrated increased corticospinal excitability after practice. EXE led to prolonged increases in intermuscular coherence and corticospinal excitability compared to CON, and changes in corticospinal excitability were associated with total learning effects from baseline to day7. These results demonstrate that acute exercise prolongs practice-dependent increases in corticospinal excitability during early memory consolidation. The study provides insights into the potential of exercise to enhance motor learning and neuroplasticity in older adults.