Association Between Leg Muscle Coordination And Subjective Energy-fatigue States During Walking

Subjective feelings of mental and physical energy and fatigue (ME, PE, MF, PF) have shown to influence walking gait. However, their relationship with muscle coordination remains unknown. PURPOSE: To investigate the relationship between changes in ME, PE, MF, and PF and leg muscle coordination during walking. METHODS: Participants (n = 26, 16 females, Mage = 23.04 ± 5.64y) completed four days of 30-minute walking around a 10x14m track, under randomly assigned conditions (silence, music, positive, and negative cues) meant to modify ME, PE, MF, PF. Moods were assessed before and at each five-minute interval. Changes in moods were calculated by subtracting scores at the previous timepoint from the following timepoint (e.g. T2-T1). Bilateral surface EMG data from quadriceps femoris (QF) and tibialis anterior (TA) muscles were recorded. Principal component analysis (PCA) was applied to the initial and final 10 seconds of each 5-minute walk to capture muscle coordination patterns. Only the first principal component (PC1) was retained due to its high variance capture, and changes in PC1 eigenvalue, variance ratio, and muscle contributions were calculated between the two time points. After data cleaning, 437 observations from 22 subjects were analyzed using Bayesian multivariate mixed-effects regression with posterior mean estimates (PME) and 95% confidence intervals (CI) used to interpret results. RESULTS: Left and right TA contributions increase as feelings of PE (left PME = 7.59, CI [0.77, 14.71], right PME = 8.06, CI [1.22, 15.19]) and ME (left PME = 7.52, CI [0.48, 14.35], right PME = 8.17, CI [1.07, 15.11]) increase. Increases in ME (PME = -3.12, CI [-6.00, -0.22]) and MF (PME = 3.66, CI [0.78, 6.49]) changed QF contributions in the opposite direction. Furthermore, with time PF increased (PME = 1.45, CI [0.11, 2.81] while ME [PME = -1.36, CI [-2.72, -0.03]) decreased. All other outcomes were less conclusive due to the inclusion of 0 in the CI. CONCLUSION: ME and MF contributions to coordination patterns for the leg muscle coordination during walking changed in the expected directions, whereas PE and ME act similarly to affect leg muscle coordination during walking. Interestingly, auditory conditions showed no impact on mood traits. Findings suggest that moods and neuromotor patterns interplay to affect physical movement. Supported by: USAID- GSP-T-204 USAID- GSP-P-119 USAID- GSP-P-120