Impact of different types of muscle exercises on the motor cortex of healthy young and older subjects
Given that ageing is associated with a decline in muscle function, itself associated with a reduction in quality of life and an increased risk of mortality, this study explores the potential of eccentric muscle exercises to increase cortical activity in the elderly and combat progressive loss of muscle function.
Differential effects of concentric and eccentric contractions on the primary motor cortex in healthy young and elderly participants
Main lessons
- This study is the first to investigate cortical activity during eccentric contractions of the lower limbs in the elderly.
- The results show that eccentric contractions induce greater cortical activation compared to concentric contractions.
- In older adults, who typically have reduced cortical activity, this type of contraction could stimulate brain neuroplasticity and improve muscle function.
Key takeaways
The results confirm that cortical plasticity is maintained in this context and support the relevance of proposing eccentric muscular exercises to tackle age-related loss of strength.
Methodology
This prospective study included 32 healthy participants (17 young people and 15 older adults). Muscle strength was measured with an isokinetic ergometer, muscle activity via electromyography and cortical activity by EEG. Participants performed 40 concentric contractions and 40 eccentric contractions at 20% of their maximum contraction. The EEG analysis looked at negative cortical potential (NP), assessing latency and amplitude as indicators of cortical activity during movement preparation and execution.