The Study
Influence of Adding Single-Joint Exercise to a Multijoint Resistance Training Program in Untrained Young Women.
This study looked at two groups of young women who did different workouts and saw that one group’s arms got a tiny bit bigger, but both groups got equally stronger. But we don’t know if the groups were picked fairly, so we can’t say the extra exercises caused the bigger arms — it might just be luck.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Two groups of women did different arm workouts for 8 weeks. One group did only big compound moves, the other added isolated arm exercises. Both got stronger and their arms looked a bit more toned, but the extra arm exercises didn't help them lift more weight.
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 538 / 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.
- 1The tiny difference in arm size isn't meaningful for real-life strength or appearance — the extra exercises didn't help strength at all.
- 2Arm circumference went up 4.39% with extra exercises vs.
- 33.50% without.
- 4Strength gains were nearly identical: elbow extension +28%, elbow flexion +29%, knee extension +27%.
- 5Skinfolds dropped about 3% in both groups.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of Strength and Conditioning Research
Year
2020
Authors
Matheus Barbalho, P. Gentil, Rodolfo Raiol, J. Fisher, J. Steele, V. Coswig
Related Content
Claims (4)
If you're new to lifting, doing big lifts like presses and squats is just as good for getting stronger as doing those plus extra isolated arm exercises.
Doing extra arm exercises along with big compound lifts like squats and presses makes arms a little bigger, but doesn’t make you stronger than doing just the big lifts alone.
Whether you do just compound lifts or add arm isolation moves, both ways help reduce arm fat a little bit — and neither is better than the other.
Muscles that span two joints grow more when trained with exercises that move only one joint, compared to exercises that move multiple joints at once, because of reduced mechanical efficiency during compound movements.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.