Jill A. Manners and James R. Scifers
Column-editor : Jeff G. Konin
Aimee E. Roth, Michael G. Miller, Marc Ricard, Donna Ritenour and Brenda L. Chapman
It has been theorized that aquatic balance training differs from land balance training.
To compare the effects of balance training in aquatic and land environments.
Between-groups, repeated-measures design.
Biomechanics laboratory and pool.
24 healthy subjects randomly assigned to aquatic (n = 8), land (n = 10), or control (n = 6) groups.
Four weeks of balance training.
Main Outcome Measures:
Balance was measured (pre, mid, post, follow-up). COP variables: radial area, y range, x range in single leg (SL), tandem (T), single leg foam (SLF), and tandem form (TF) stance.
A significant condition × time interaction for x range was found, with improvements for SL, SLF, and TF. Radial area improved, with post-test 1.01 ± .23 cm2 and follow-up 1.06 ± .18 cm2 significantly lower than pretest 1.18 ± .23 cm2. Y range significantly improved, with posttest (4.69 ± 1.02 cm2) lower than pretest (5.89 ± 1.26 cm2). The foam conditions (SLF & TF) were significantly different from non-foam conditions (SL & T) for all variables.
Results of this study show that balance training can effectively be performed in both land and aquatic environments.
Eadric Bressel, Gerald Smith, Andrew Miller and Dennis Dolny
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.