The Influence of Pre-Training Muscle Size on Strength Gain: An Exploratory Analysis
The IUSCA's International Journal of Strength and Conditioning is the world leading Diamond Open Access journal in S&C and Sport Science. We have recently published a new article by Hammert, W., Song, J. S., Yamada, Y., Kataoka, R., Kang, A., Sallberg, R., Metcalf, E., & Loenneke, J. (2026). titled "The Influence of Pre-Training Muscle Size on Strength Gain: An Exploratory Analysis”
Abstract
Purpose: To investigate whether changes in maximal strength following resistance training were influenced by pre-training muscle thickness.
Methods: We retrospectively analyzed data from a between-subject study that measured elbow flexor muscle thickness and maximum strength before and after a 6-week study. A total of 122 untrained individuals, who were randomly assigned to 1 of 3 groups, were included in the analyses: (a) time-matched, non-exercise control; (b) dominant arm training; or (c) nondominant arm training. The two training groups performed thrice weekly unilateral elbow flexion exercise, starting with up to 5 heavy singles, followed by 4 sets of 8–12 repetitions to task failure.
Results: Increases in strength were observed for both dominant arm [b = 2.29 kg, 95% CI = (1.72, 2.87)] and the non-dominant [b = 2.86 kg, 95% CI = (2.33, 3.39) training groups compared to the time-matched non-exercise control group. However, this increase in strength did not depend upon baseline muscle size for either group. Follow-up mediation analyses suggested that muscle growth mediated changes in strength for the dominant arm but not the nondominant arm training group.
Conclusion: We hypothesized that individuals with larger muscles at baseline would have a greater propensity to increase strength compared to those with smaller muscles. However, the magnitude of strength change was not influenced by pre-training muscle thickness. Follow-up mediation analysis on muscle growth was equivocal.
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