Do Changes In Mental And Physical Energy And Fatigue Impact Changes On Neck Muscle Coordination?

Subjective feelings of mental and physical energy and fatigue (ME, MF, PE, PF) have been shown to influence human movement. However, we are unaware of evidence showing an association between changes in individuals' mood states and neuromuscular coordination. PURPOSE: To examine the association between changes in ME, MF, PE, PF and neck muscle coordination. METHODS: A randomized, crossover design was used to induce positive and negative changes in ME, MF, PE and PF. Participants (n = 26, age = 23.04 ± 5.64y) walked around a 10x14m track while wearing noise cancelling headphones under four randomly assigned conditions (silence, music, positive, and negative auditory cues). Moods were measured at baseline and at 5-minute intervals during the 30-minute walk per condition. Mood changes were calculated by subtracting the scores at the previous timepoint from the following timepoint (e.g. T2-T1). Neuromuscular coordination of the left and right cervical erector muscles (CEM) and sternocleidomastoid muscles (SCM) was assessed by using sEMG data taken 10s after mood data collection and 10s before subsequent mood data collection. Principal component analyses were used on the first and the last 10s EMG data. Changes in eigenvalue, variance ratio, and contributions of each muscle to the first principal component (CP1) were calculated for each time point. Bayesian multivariate mixed effects regression, with posterior mean estimates (PME) and 95% confidence interval (CI), was used due to non-normality and the four mood states assessed. RESULTS: There was a significant participant effect for all moods but also a time effect for ME, PF, and MF. The contribution of the right SCM to CP1 decreased with increases in ME (PME = -3.53, 95% CI = [-5.97, -1.11]) suggesting that the right SCM contributes less to the neck movement pattern as mental energy increases. The effects of the other muscles on ME, MF, PE and PF are less conclusive due to the inclusion of 0 in the 95% CI. CONCLUSIONS: The findings of this exploratory study suggest that neck muscle coordination may change with subjective feelings of mental energy. A further examination of other muscles and other neuromuscular coordination patterns is needed to identify how changes in these moods influence motor coordination. Supported by: People who were directly funded by grant- Ahmed Torad, Ahmed Kadry, Emily, Ryan, Ali Grant numbers USAID- GSP-T-204 USAID- GSP-P-119 USAID- GSP-P-120