The Affect of Altered Exercise Intensity on Postural Stability

PURPOSE: To determine if the center of balance was affected by the administration of bouts of exercise performed at different intensities. Our secondary aim was to determine how long it took for balance to return to baseline assessment values, following cessation of exercise. METHODS: 16 male subjects (25±5yrs, 183±10cm, 73±11kg, 4.4±.73 LO2?/min) volunteered and provided their informed written consent for the study. Participants were free of balance disorders and recent history of concussion. Subjects visited the lab twice and performed exercise at 40, 60, 80, 100, and 120% of the level necessary to elicit a maximal response from the body’s respiratory and circulatory systems. Following each bout of exercise, balance scores were assessed every 5 minutes for 30 minutes from a portable force plate in four conditions: normal stability eyes open (NSEO), normal stability eyes closed (NSEC), perturbed stability eyes open (PESO), and perturbed stability eyes closed (PSEC). Perturbed stability required subjects to stand on a foam mat placed on the fore plate. RESULTS: Two-way anova indicated that following 120% intensity there was a significant decrease in NSEO from baseline. Stability scores returned to baseline after ten minutes. Our findings suggest a similar impaired stability following exercise at 80% intensity. CONCLUSIONS: Our results showed that immediately after exercising at 120% intensity there was a decrease in stability score compared to baseline. We conclude that balance is impaired for at least 10 minutes following vigorous exercise. These assessments and findings should be incorporated into sideline testing procedures used for the diagnosis of concussion in sport