Sex differences in the impact of state and trait fatigue on gait variability

Conditions requiring greater attention or cognitive control, such as fatigue, lead to changes in the motor performance of a task. Perceived fatigue refers to subjective feelings of fatigue, can be expressed as a state variable or trait characteristic and is influenced by demographic factors, such as sex. The purpose of this study was to determine how sex interacts with state and trait physical fatigue (PF) and mental fatigue (MF) to influence gait variability. METHODS: 123 healthy adults (77 female, 46 male), aged 18-36 years, completed the Mental and Physical State and Trait Energy and Fatigue Scale. Using a median split for each fatigue variable, participants were placed into "low" or "high" fatigue categories. Gait variability was defined as the asymmetry of lateral step variability (ALSV) and coefficient of variation (CV) of gait speed, stride length and double limb (DL) support during overground walking. RESULTS: Males with low state PF had greater ALSV than females with low state PF (p = 0.05, eta 2p = 0.07) and males with high state PF (p = 0.007, eta 2p = 0.15). Females with high trait MF had greater CV of gait speed than females with low trait mental fatigue (p = 0.02, eta 2p = 0.08). Males with low trait MF had greater CV of gait speed (p = 0.01, eta 2p = 0.10) and stride length (p = 0.002, eta 2p = 0.17) than females with low trait MF. CV of DL support did not vary based on fatigue level or sex (p >= 0.11). CONCLUSIONS: There are sexspecific differences in the impact of state PF on asymmetry of lateral step variability and trait MF on the variability of gait speed and stride length.