The Study
Lighter-Load Exercise Produces Greater Acute- and Prolonged-Fatigue in Exercised and Non-Exercised Limbs
We don't know how the experiment was done — no one told us if people were randomly assigned or if anyone was comparing things fairly. So we can't say for sure if lighter weights really make you more tired. It's like hearing a story without seeing the proof.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
This study tested whether lifting light weights until you can't anymore makes you more tired than lifting heavy weights, even when you do the same total amount of work.
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 544 / 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 — even if you do the same total work, lifting lighter weights for more reps may leave you more tired and sore for longer, and feel harder, which could affect how often you can train.
- 2Light weights (40% max) made both the lifted leg and the other leg more tired than heavy weights (80% max).
- 3The lifted leg didn't fully recover strength after 48 hours with light weights, but did after 24 hours with heavy weights.
- 4People rated light weight lifting as more uncomfortable (10/10 vs.
- 58/10).
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Research Quarterly for Exercise and Sport
Year
2020
Authors
Joshua Farrow, J. Steele, David G. Behm, Martin Skivington, J. Fisher
Related Content
Claims (3)
In resistance-trained men, performing resistance exercises with lighter weights (40% of maximum strength) causes more fatigue in both the worked muscle and the opposite limb than using heavier weights (80% of maximum strength), and the worked muscle does not fully recover after 48 hours with lighter weights, while the non-worked limb only shows fatigue after lighter-weight exercise.
Men who regularly train with weights report greater discomfort when performing resistance exercises at 40% of their maximum strength until failure, compared to exercises at 80% of their maximum strength until failure, with average discomfort scores of 10 versus 8.
In men trained in resistance exercise, muscle strength returns to baseline levels within 24 hours after a workout performed with heavy weights (80% of maximum strength), but not after a workout performed with lighter weights (40% of maximum strength), when both workouts involve the same total volume and are taken to muscular failure.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.