The effects of concentric and eccentric exercise performed at long muscle length on muscle damage.
Level 2 - randomized trial
randomized within-subject experimental trial
PubMed 41131693 · doi:10.1080/02640414.2025.2577034
What was done
Thirteen female participants performed 75 maximal voluntary isokinetic contractions of the elbow flexors at long muscle length (range of motion: 5°–50°, where 0° is full extension). One arm was randomly assigned to concentric contractions and the contralateral arm to eccentric contractions. Muscle damage indices and ultrasound parameters (isometric peak torque, range of motion, delayed onset muscle soreness [DOMS], muscle thickness, and echo intensity of the biceps brachii and brachialis) were assessed before and at 24, 48, 72, and 96 hours post-exercise.
What was found
No significant main effect of exercise type or exercise type-by-time interaction was observed for any measured parameter (p = 0.097 to 0.873). A significant main effect of time occurred for all measured parameters (p < 0.01). Isometric peak torque and range of motion decreased significantly at 24 hours post-eccentric exercise (p < 0.05). DOMS and muscle thickness increased significantly after both exercise types (p < 0.001), while echo intensity changed significantly only after eccentric exercise (p < 0.001). The abstract reports p-values but no means, standard deviations, or effect sizes.
Why it matters
This study shows that unfamiliar maximal concentric contractions performed at long muscle lengths can induce muscle damage comparable to eccentric exercise. This challenges the standard view that exercise-induced muscle damage is driven almost exclusively by eccentric actions.
Limits
The sample size was very small (n = 13) and restricted exclusively to female participants. The abstract lacks baseline values, point estimates, and confidence intervals. Findings from isolated isokinetic elbow flexion may not generalize to other muscle groups, male cohorts, or free-weight resistance exercise.
Cited by
- supports Concentric exercise can cause muscle soreness and muscle damage.