Sex-related differences in fine motor skills and muscle strength control during short-term fasting

Despite the growing relevance of fasting-related effects on health promotion, studies related to its impact on motor behavior remain scarce. Thus, the aims of the present study were to determine the effects of short-term fasting on fine motor skills and muscle strength control, and to assess whether these fasting-induced effects are sex-dependent. Healthy, nonobese male (n = 14) and female (n = 14) participants underwent a 48-h fast. Changes in fine motor skills, reflexes (V-wave, H-wave and M-wave), involuntary muscle torque, maximal voluntary contraction (MVC) and central activation ratio (CAR) during MVC were measured. Only females showed an increase in the time to complete the fine motor skills test after a 48-hour fast, from 46.3 ± 5.16 s to 49.0 ± 5.40 s (p < 0.05). Fasting had no effect on MVC, and involuntary muscle torques. However, a sex difference in the CAR was observed indicating fasting-associated CAR decrease from 94.5 ± 7.4% to 90.1 ± 10.5% in females but not in males (p < 0.05). Moreover, a decrease in the H-wave normalized by the M-wave, from 0.68 ± 0.27 to 0.60 ± 0.26, and a shortened V-wave latency, from 38.1 ± 2.81 ms to 37.0 ± 2.54 ms, were observed only in females (p < 0.05). To conclude, 2-days’ fasting decreased fine motor skills performance only in females. Nevertheless, females exhibited modulations at supraspinal and spinal level, muscle torque was preserved, and fasting was accompanied with maintained muscle strength in both sexes. Trial registration Retrospectively registered on ClinicalTrials.gov (NCT05545943).