ItemThe effect of selected rest break activities on reaction time, balance, and perceived discomfort after one hour of simulated occupational whole-body vibration exposure in healthy adults(Taylor & Francis, 2023-08-12) Burnett, Wadena D; Tweten, Michael; Okpalauwaekwe, Udoka; Trask, Catherine; Milosavljevic, StephanBackground & Objective Negative health effects from occupational whole-body vibration (WBV) exposure during machinery operation include alterations in proprioception, vestibular function, reaction time, stress, motor response, and decrements in musculoskeletal health. To reduce WBV exposure during machinery operation, it may be possible to incorporate short rest break activities throughout the day. This study aims to determine if there are intervention activities that can minimize decrements in cognitive, proprioceptive, and musculoskeletal effects related to WBV exposure during machine operation. Materials & Methods Eleven healthy adults participated in four 1-hour sessions of ecologically valid WBV exposure followed by one of four 5-minute activities: sitting, walking, 2 minutes of gaze stabilization exercise (GSE) coupled with 3 minutes of trunk mobility exercise (GSE+MOBIL), or 2 minutes of GSE coupled with a 3-minute walk (GSE+WALK). Baseline and post-activity measurements (rating of perceived discomfort, balance and postural sway measurements, 5-minute psychomotor vigilance task test) were submitted to a paired t-test to determine the effect of WBV exposure and activities on physical, cognitive, and sensorimotor systems and to a repeated measures ANOVA to determine any differences across activities. Results We observed degradation of the slowest 10% reaction speed outcomes between baseline and post-activity after walking (7.3%, p<0.05) and sitting (8.6%, p<0.05) but not after GSE+MOBIL or GSE+WALK activities. Slowest 10% reaction speeds after GSE+MOBIL activity was faster than all other activities. Rating of perceived discomfort was higher after SIT and WALK activities. There were no notable differences in balance outcomes. Conclusion When compared to sitting for 5 minutes, an activity including GSE and an active component, such as walking or trunk mobility exercises, resulted in maintenance of reaction time after WBV exposure. If confirmed in occupational environments, GSE may provide a simple, rapid, effective, and inexpensive means to protect against decrements in reaction time after WBV exposure. ItemValidation of a portable force plate for in-field measurements of balance and postural sway(2022-03-21) Burnett, Wadena D; Okpalauwaekwe, Udoka; Milosavljevic, StephanObjective: To determine how balance outcomes measured using a portable force platform (FP4, Biometrics Inc) compare to balance measurements from an in-floor mounted force plate (6090-15, Bertec Corp). Methods: Twenty adult volunteers stood on the measurement platform for two trials, 10min apart, to measure bi-pedal medial-lateral and anterior-posterior balance with eyes opened and closed. We measured root mean square, range, and mean velocity of variability of center of pressure from each force plate. Pearson correlation was used to determine relationships between force plate outcomes. Intraclass correlation coefficients (ICC) were used to determine measurement reliability. Differences between eyes open and closed outcomes from each device were determined using t-tests. Results: Correlations between portable and in-floor force plate outcomes ranged from 0.73 to 0.98. ICC values ranged from 0.07 to 0.54. Differences between eyes open and closed outcomes were observed in the anterior-posterior directions on both devices.