The Study
Changes in agonist neural drive, hypertrophy and pre-training strength all contribute to the individual strength gains after resistance training
This study found that people who got stronger after lifting weights tended to also have bigger muscles and better nerve signals to their muscles — but it doesn’t prove that those things made them stronger. It just shows they went together.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
When people start lifting weights, their muscles don't grow right away—first, their brain gets better at telling muscles to work harder.
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 525 / 100
Quality score
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes—nearly 60% of why people get stronger at different rates can be explained by these three factors, meaning training should focus on both brain-muscle connection and muscle growth.
- 2After 12 weeks: brain signals explained 30.6% of strength gains, muscle growth explained 18.7%, and weaker people at the start improved more (10.6%).
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
European Journal of Applied Physiology
Year
2017
Authors
T. G. Balshaw, G. Massey, T. Maden-Wilkinson, Antonio J. Morales-Artacho, Alexandra McKeown, Clare L. Appleby, J. Folland
Related Content
Claims (10)
Increases in strength are mainly due to changes in how the nervous system activates muscles, while increases in muscle size are mainly due to the total amount of training performed within a repetition range of 4 to 30 reps.
When you first start lifting weights, you get stronger not because your muscles grow bigger right away, but because your brain gets better at telling your muscles when and how to contract.
The amount of electrical activity in the quadriceps muscle during a maximal effort is the best single indicator of how much strength a person will gain after 12 weeks of weight training, explaining about 30.6% of the differences in strength gains between individuals.
After 12 weeks of resistance training in healthy young men, increases in quadriceps muscle size account for about 18.7% of the differences in strength gains, suggesting that changes in muscle size play a role but are less influential than changes in nervous system function.
People who are already stronger before starting resistance training tend to gain less absolute strength over time compared to those who start weaker, and their initial strength level accounts for about 10.6% of the differences in how much they improve.
If you're already strong before starting isometric training, you won't get as much stronger compared to someone who started weaker — and this pattern explains about 1 in 10 of the differences in how much people improve.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.