Oxygen cost and energy expenditure of racquetball

Many sports are played intermittently in bursts of high, moderate, and low intensity activity. The pattern of exercise intensity has been assessed from heart rate (HR) and time motion analysis and few data are available based on assessment of exercise intensity by means of direct measurement of oxygen uptake. The aim of this study was to directly assess oxygen uptake (VO(2)) using a portable metabolic measuring device to describe the aerobic demand and to determine the associated energy expenditure (EE).

Fourteen recreational racquetball players (3 females and 11 males; mean age, height, and mass of 23.1+/-2.8 years, 178.1+/-7.1 cm, and 81.1+/-19.6 kg, respectively) played for 40 min while wearing a portable metabolic system to assess VO(2) and a Polar watch to measure HR. Rating of perceived exertion (RPE) (Borg 6-20 scale) was assessed at 5 min intervals during breaks in play.

The mean VO(2), HR, and RPE over 40 min of play were 27.3+/-1.8 mL/kg/min, 155.3+/-2.8 bpm, and 12.9+/-0.6, respectively. The associated EE was a total of 1 844 kj (440 kcal) or 465 kj/min (11.1 kcal/min). These data were examined across 13.3 min time periods of play, in order to determine if they changed during play because of fatigue. VO(2) decreased significantly (P<0.05), while HR increased (P<0.05). RPE rose across periods of play, but not significantly.

Recreational racquetball appears to elicit a VO(2) that would allow aerobic conditioning in many persons. It does so with an RPE that is nearly ''somewhat hard''.