The Study
The effects of concentric and eccentric exercise performed at long muscle length on muscle damage
This study shows what happened to muscles after different types of exercise in a small group of women. It can tell us that muscle soreness and changes happened after the workouts, but it can't prove that one type of exercise caused more damage than the other.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Women did arm exercises at long muscle lengths, either shortening or lengthening their muscles. Scientists checked for soreness, swelling, and muscle damage over four days.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 539 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes, this means doing unfamiliar arm exercises at long muscle lengths can make your arms sore and weak for days, especially if you're lowering weights.
- 2Both types of exercise made arms sore and swollen.
- 3Lengthening exercises caused more muscle damage signs and made arms weaker right after.
- 4These changes lasted up to four days.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of Sports Sciences
Year
2025
Authors
Anastasia V Karyofyllidou, G. Terzis, D. Mandalidis, Nikos V. Margaritelis, V. Paschalis
Related Content
Claims (4)
When women do certain types of arm exercises that involve stretching the muscle while contracting it, they tend to feel more soreness and their muscles get thicker — probably because of inflammation and fluid buildup.
Doing certain types of hard arm exercises that lengthen the muscle while it's working can make your arms weaker and less flexible within a day.
Doing a new type of strength exercise that stretches your biceps a lot can cause temporary muscle damage and soreness in women, and these effects can last up to four days.
Doing super-slow, lengthening muscle exercises (like lowering a heavy weight) causes more muscle damage than shortening ones, and you can see it on an ultrasound of your arm muscles.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.