The Claim

In recreationally active adults, changes in pectoralis major muscle thickness show a weak correlation (r = 0.20–0.26) with changes in maximal isometric strength following 8 weeks of either static stretching or resistance training, indicating that muscle hypertrophy accounts for only a small proportion of strength improvements.

Source: Influence of 8-weeks of supervised static stretching or resistance training of pectoral major muscles on maximal strength, muscle thickness and range of motion

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
47score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Correlation
1 study reviewed
In plain English

If you stretch or lift weights for 8 weeks, your chest muscle might grow a little, but that growth doesn’t explain much of why you get stronger—other factors are probably doing more of the work.

See the scientific wording

In recreationally active adults, changes in pectoralis major muscle thickness are weakly correlated with changes in maximal isometric strength (r = 0.20–0.26), suggesting that muscle growth explains only a small portion of strength gains following 8 weeks of static stretching or resistance training.

What the research says

1 study
  1. Study: Influence of 8-weeks of supervised static stretching or resistance training of pectoral major muscles on maximal strength, muscle thickness and range of motion

    The study found that people got stronger after stretching or lifting weights, but the gains in strength weren’t tightly linked to how much their muscles grew, which supports the idea that muscle size isn’t the main reason for getting stronger.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.