Condition-Dependent Sex Differences in Lumbar sEMG and Prefrontal Hemodynamics During Known-Weight and Weight-Misprediction Lifting: A Pilot Study

This pilot study examined sex-related neuromuscular and prefrontal hemodynamic responses across 3 and 9 kg known-weight and weight-misprediction lifting conditions and explored whether these patterns differed by physical activity level (PAL). Thirty adults completed the lifting tasks. Among the unknown-weight trials, only wrong-guess trials were retained, while the known-weight trials served as comparison conditions. The integrated linear mixed-effects model showed a significant Condition × Sex interaction, indicating that sex-related differences varied across lifting conditions. The omnibus condition and sex effects were also significant, whereas PAL and all interactions involving PAL were not significant. Exploratory PAL-stratified analyses showed condition-dependent sex differences within both PAL groups. In the moderate PAL group, women showed higher task-related ΔHbO β-values than men across multiple channels under the 3 kg wrong-guess condition after false discovery rate correction. These preliminary findings suggest condition-dependent sex-related neuromuscular responses and sex-related differences in prefrontal hemodynamic responses observed under the 3 kg wrong-guess condition. The exploratory subgroup findings require confirmation in larger and more balanced samples.