July 2026; Vol. 15, No. 2: Pages 16-20
Does cross-education of strength depend on limb dominance? Testing baseline strength differences as moderator
Jun Seob Song, William B. Hammert, Yujiro Yamada, Ryo Kataoka, Jeremy P. Loenneke
Abstract
Cross-education of strength refers to strength gains in the opposite untrained limb. It was previously proposed that the magnitude of cross-education effect may be contingent upon how much stronger the dominant limb is relative to the non-dominant limb before training. Objectives: To examine whether the magnitude of cross-education depends on the baseline strength difference between the dominant and non-dominant arm, as well as individuals' preference for using their dominant arm in daily activities. Design: Retrospective analyses. Methods: 73 untrained individuals were randomly assigned to either a time-matched non-exercise control group or a training group. The training group performed unilateral elbow flexion exercise with the dominant arm (x3/week for 6 weeks). Maximum strength of the non-dominant was measured before and after the intervention. Moderation analyses were conducted with baseline strength difference and handedness score as moderators. Results: No significant group by baseline strength difference interaction was found for strength changes of the non-dominant arm (i.e., cross-education of strength) [b = 0.255, CI = (-0.259, 0.769), SE 0.257, p = 0.352]. Similarly, there was no statistically significant group by handedness score interaction for strength changes of the non-dominant arm [b = -0.028, CI = (-0.117, 0.062), SE 0.045, p = 0.537]. Conclusions: Six weeks of unilateral high-load resistance training induced a cross-education effect, however, its magnitude was not dependent on baseline strength differences between limbs. The limited variability in handedness in the present sample may have restricted the ability to fully evaluate its potential moderating role, and thus, further research is warranted.
Received March 24, 2026; accepted July 20, 2026