When young men who had never lifted weights before trained their legs for 15 weeks, the more their leg muscles grew, the stronger they got—this link was extremely strong.
Scientific Claim
In previously untrained young men, muscle growth following 15 weeks of lower body resistance training is very strongly associated with increases in isometric knee extension strength (r = 0.92) and one-repetition maximum strength (r = 0.89), suggesting that hypertrophy is a primary contributor to individual strength gains in this population.
Original Statement
“Very strong repeated-measures correlations were found between muscle growth and strength gains (iMVT: r = 0.92, P < 0.001; 1RM, r = 0.89, P < 0.001).”
Evidence Quality Assessment
Claim Status
appropriately stated
Study Design Support
Design supports claim
Appropriate Language Strength
association
Can only show association/correlation
Assessment Explanation
The study design is observational and within-participant, which can only show association, not causation. The authors correctly use correlation coefficients and avoid causal language in the results, making the claim appropriately framed.
Evidence from Studies
Supporting (1)
This study found that when untrained guys got stronger after lifting weights for 15 weeks, most of that strength gain came from their muscles growing bigger—not just from their nerves getting better at firing. The bigger the muscle growth, the stronger they got, and this link was extremely strong.