David C. Berry and Michael G. Miller
W. Jack Rejeski, Edward Gregg, Amy Thompson and Michael Berry
In this investigation, we examined the role of acute aerobic exercise (AE) in buffering physiological responses to mental stress. Twelve trained cyclists participated in three counterbalanced treatment conditions on separate days: attention control, light exercise (50% of VO2max for 30 min), and heavy exercise (80% of VO2max for 60 min). After a 30-min rest period following each condition, subjects completed a modified Stroop task. Blood pressure (BP) and heart rate (HR) were monitored for (a) baseline responses, (b) task reactivity, and (c), 5 min of recovery following the stressor. Mean arterial pressure (MAP) revealed that reactivity was attenuated by both heavy- and light-exercise conditions as compared to responses in the control condition. Moreover, heavy exercise was more effective in reducing MAP reactivity than light exercise. Systolic BP during the task was significantly higher in the control and light-exercise conditions than following heavy exercise; diastolic BP was significantly higher in the control condition than in either exercise condition. There were no significant effects for HR. These results suggest that there is a dose-response relationship between acute AE and the attenuation of psychophysiological reactivity during stress.
Michael G. Miller, David C. Berry, Susan Bullard and Roger Gilders
Land and aquatic plyometrics have clinical relevance for exercise, sport performance, and rehabilitation, yet study is limited comparing both.
To compare the effects of land-based and aquatic-based plyometric-training programs on performance variables, muscle soreness, and range of motion (ROM).
Aquatic facility and biomechanics laboratory.
Forty subjects randomly assigned to 3 groups: land (n = 13), water (n = 13), and control (n = 14).
Main Outcome Measures:
Performance variables, muscle soreness, and ROM were measured before and after an 8-week training period. An analysis of covariance (ANCOVA) and a Bonferroni post hoc test determined significance.
ANCOVA revealed significant differences between groups with respect to plantar-flexion ROM (P < .05). Paired t test determined that the aquatic group significantly increased muscle power pretest to posttest (P < .05).
Results indicate that aquatic plyometric training can be an alternative approach to enhancing performance.