Search Results

The purpose of this study was to examine the relationships among body mass index (BMI), body image perception, physical activity habits, and exercise stage of change in college-aged females. Volunteers (N = 134) completed a survey of demographics, Stage of Exercise Scale (SOES; Cardinal, 1995a; Cardinal, 1995b), Physical Activity History questionnaire (PAH; Jacobs, Hahn, Haskell, Pirie, & Sidney, 1989), and Body Shape Questionnaire (BSQ; Cooper, Taylor, Cooper, & Fairburn, 1987). Participants were categorized into five exercise stages of change: precontemplation, contemplation, preparation, action, and maintenance. Relationships between the variables were analyzed with Pearson r correlations. Kruskal-Wallis independence tests were also used for analyses. Approximately 60% of the participants reported current physical inactivity or irregular exercise. BMI and body image score were significantly linearly related, with higher body mass indicating more negative body image (r = 30, p <.017). Significant differences existed between exercise stages for physical activity score, X² (3, N = 134) = 19.98, p <.05. Based upon follow-up tests participants in the maintenance stage had significantly higher physical activity scores than all other stages. No significant differences were found for BMI or body image between exercise stages. Regular exercisers had the highest frequency of disordered eating and weight-preoccupied attitudes and behaviors. The majority of these women were not currently regularly physically active, professed dissatisfaction with their current level of activity, and expressed a fear of being fat. Further study directed at specific factors related to body image and exercise behaviors, as well as the impact of stage-specific interventions are suggested.

Context: The aquatic environment provides a low-impact alternative to land-based exercise and rehabilitation in older adults. Objective: Evaluate the biomechanics of older adults and young adults performing jumping movements on land and in water. Design and Setting: Cross-sectional, mixed-factorial experiment; adjustable-depth pool at sports medicine research facility. Participants: Fifty-six young adults (age = 22.0 [3.9] y) and 12 healthy older adults (age = 57.3 [4.4] y). Interventions: Each participant performed 6 maximal effort countermovement jumps: 3 jumps were performed on land, and 3 other jumps were performed with participants immersed in chest-deep water. Main Outcome Measures: Using data from the amortization and propulsive phases of jumping, the authors computed the following kinetic and kinematic measures: peak and mean mechanical power, peak force, amortization time and rate, unweighting and propulsive times, and lower-extremity segment kinematics. Results: Mechanical power outputs were greater in younger adults (peak: 7322 [4035] W) versus older adults (peak: 5661.65 [2639.86] W) and for jumps performed in water (peak: 9387 [3981] W) versus on land (peak: 4545.84 [1356.53] W). Peak dorsiflexion velocities were greater for jumps performed in water (66 [34] deg/s) versus on land (4 [7] deg/s). The amortization rate was 26% greater in water versus on land. The amortization time was 20% longer in older adults versus young adults. Conclusions: Countermovement jumps performed in water are mechanically specific from those performed on land. Older adults jumped with longer unweighting times and increased mechanical power in water. These results suggest that aquatic-based exercise and rehabilitation programs that feature jumping movements may benefit older adults.

Context: Quantification of the magnitudes of fluid resistance provided by water jets (currents) and their effect on energy expenditure during aquatic-treadmill walking is lacking in the scientific literature. Objective: To quantify the effect of water-jet intensity on jet velocity, drag force, and oxygen uptake (VO₂) during aquatic-treadmill walking. Design: Descriptive and repeated measures. Setting: Athletic training facility. Participants, Interventions, and Measures: Water-jet velocities were measured using an electromagnetic flow meter at 9 different jet intensities (0-80% maximum). Drag forces on 3 healthy subjects with a range of frontal areas (600, 880, and 1250 cm²) were measured at each jet intensity with a force transducer and line attached to the subject, who was suspended in water. Five healthy participants (age 37.2 ± 11.3 y, weight 611 ± 96 N) subsequently walked (~1.03 m/s or 2.3 miles/h) on an aquatic treadmill at the 9 different jet intensities while expired gases were collected to estimate VO₂. Results: For the range of jet intensities, water-jet velocities and drag forces were 0-1.2 m/s and 0-47 N, respectively. VO₂ increased nonlinearly, with values ranging from 11.4 ± 1.0 to 22.2 ± 3.8 mL × kg^-1 × min^-1 for 0-80% of jet maximum, respectively. Conclusions: This study presented methodology for quantifying water-jet flow velocities and drag forces in an aquatic-treadmill environment and examined how different jet intensities influenced VO₂ during walking. Quantification of these variables provides a fundamental understanding of aquatic-jet use and its effect on VO₂. In practice, these results indicate that VO₂ may be substantially increased on an aquatic treadmill while maintaining a relatively slow walking speed.