A thletes of all ages enjoy participating in sporting activities. Children and adolescents participate in youth sports teams, while adults enjoy events such as running races, triathlons, and adult sport leagues. This type of recreational sportsenthusiast comprises the majority of the athletic population. However, a small percentage of athletes chooses to pursue a higher and more demanding level of training and competition. Some athletes excel in a sport early in adolescence and focus exclusively on those physical skills. Master-level athletes are continuing to compete well into the fifth and sixth decades of life. Athletes of this caliber level are training harder, competing more often, and taking less time to taper. As such, the elite athlete frequently suffers from overuse injuries, particularly soft tissue injuries, such as tendinitis, bursitis, and stress fractures. Selfcare for the average athletic population may include temporary rest and discontinued training. Research has shown that 3 weeks of inactivity can lead to a significant loss of cardiovascular fitness, where 6 weeks of rest can lead to a decrease of as much as 14-16% of maximal oxygen consumption (1 0.1 1,27). Because of such losses and demanding competition schedules, the elite athlete is often under time constraints for injury rehabilitation. As such, many athletes have found utili7ation of a water-based program during their "active rest" Elite athletes are competing for longer seasons, training more hours, and taking less time off. This schedule may predispose the elite athlete to overuse injuries. When an injury occurs, aquaticbased rehabilitation may expedite the recovery process, as effective cardiovascular and musculoskeletal training may be accomplished by aquatic exercise. The pool may be used both during rehabilitation and postrecovery as an adjunctive tool. Knowledge of the unique physical properties of water, as well as the physiological responses to immersion both at rest and during exercise, will aid the physical therapist when designing a rehabilitation or training program for the athlete. Understanding the principles of movement in water will provide a foundation for creative use of water's unique properties.

No abstract

Study Design: A repeated-measure crossover design was used. The independent variable was the type of ultrasound (pulsed or continuous) and the dependent variable was intramuscular temperature. Objective: To compare changes in intramuscular temperature resulting from the use of pulsed ultrasound versus continuous ultrasound with an equivalent spatial average temporal average (SATA) intensity. Background: There is a lack of research on the heat-generating capabilities of pulsed ultrasound within human muscle. Methods and Measures:The subjects were 16 healthy volunteers (mean age ± SD, 21.3 ± 2.5 years). Each subject was treated with pulsed ultrasound (3 MHz, 1.0 W/cm 2 , 50% duty cycle, for 10 minutes) and continuous ultrasound (3 MHz, 0.5 W/cm 2 , for 10 minutes) during a single testing session. Tissue temperature returned to baseline and stabilized between treatments and treatment order was randomized. Tissue temperature was measured every 30 seconds using a 26-gauge needle microprobe inserted at a depth of 2 cm in the left medial gastrocnemius muscle. Data were analyzed using a linear mixed model. Results: Treatment with continuous ultrasound produced a mean (±SD) temperature increase of 2.8°C ± 0.8°C above baseline. Treatment with pulsed ultrasound produced a mean (±SD) temperature increase of 2.8°C ± 0.7°C above baseline. Statistical analysis revealed no significant differences in either the extent or rate of temperature increases between the 2 modes of ultrasound application. Conclusion: Pulsed ultrasound (3 MHz, 1.0 W/cm 2 , 50% duty cycle, for 10 minutes) produces similar intramuscular temperature increases as continuous ultrasound (3 MHz, 0.5 W/cm 2 , for 10 minutes) at a 2-cm depth in the human gastrocnemius. Spatial average temporal average intensity is an important consideration when selecting pulsed ultrasound parameters intended to deliver nonthermal effects.

No abstract