This study considered the effects of repeated bouts of short-term resistive exercise
in old (age: 64.5±5.5 years; n = 10) and young men (age: 25.1±4.9 years; n = 10) who
performed six knee extension exercise bouts over two weeks using various markers of
exercise-induced muscle damage and electromyographic activity. We found that time-course
changes in quadriceps isometric torque, creatine kinase activity, and muscle soreness
in the two groups were similar. However, recovery in the acute torque deficit was
mediated by more favourable electromyographic activity changes in the young group
than in the older adults group. Muscle elastic energy storage and re-use assessed
with dynamometry was selectively improved in the young group by the end of the protocol.
Serum myoglobin concentration increased selectively in old group, and remained elevated
with further bouts, suggesting higher sarcolemma vulnerability and less effective
metabolic adaptation in the older adults, which, however, did not affect muscle contractility.