Evaluation of acute cardiorespiratory responses to hydraulic resistance exercise.

Accurate evaluation of the acute responses to resistance exercise training depends on the stability of the criterion measures. This is particularly true for maximal effort exercise where continuous "all-out" effort for each repetition is encouraged. The present study evaluated reliability of repetition number (repN), respiratory gas parameters (VO2, VCO2, VE), and heart rate (HR) for shoulder (SE), chest (CE), and leg (LE) exercise performed maximally on a single-unit, 3-station hydraulic resistance exercise machine (Hydra-Fitness, Belton, TX). On 2 separate days, 20 college men completed three 20-s bouts of SE, CE, and LE with a 20-s rest between bouts and 5 min between exercise modes. There were no significant differences between bouts or test days for repN, gas measures, or HR. Subjects performed 17, 19, and 21 reps during SE, LE, and CE. VO2 was 1.7 l . min-1 (24.3 ml . kg-1 . min-1) for SE, 1.87 l . min-1 (25.5 ml . kg-1 . min-1) for CE, and 2.1 l . min-1 (28.6 ml . kg-1 . min-1) for LE. These values, averaged, represented 52.8% of the max VO2 determined on a continuous cycle ergometer test. The corresponding HR's during hydraulic exercise averaged 84.6% of HR max. Test-retest reliability coefficients ranged from r = .67 to .87 for repN, r = .41 to .83 for gas measures, and r = .72 to .89 for HR.(ABSTRACT TRUNCATED AT 250 WORDS)