Physiological and spinal responses to circuit weight-training

Physiological, perceptual and physical responses to a typical circuit weight-training (CWT) regimen were recorded in two studies. The aims were to assess the intensity of exercise during CWT; and to determine whether physical responses as evaluated by spinal shrinkage were related to physiological and perceptual responses to CWT. In the first study (n = 10) heart rate (HR), oxygen consumption (VO2), ventilation (VE), blood lactate (La) and perceived exertion (RPE) were measured in response to CWT. Mean (+/- SD) time to complete three circuits of CWT was 17.8 (+/- 1.4) min. The HR max, VO2 max and peak La, measured first during an incremental treadmill test, were 195 (+/- 13) beats.min-1, 59.7 (+/- 4.8) ml.kg-1.min-1 and 14.3 (+/- 3.5) mM respectively. Mean HR and VO2 during CWT were 69% and 50% of the respective maximal values. The HR-VO2 ratio observed on the treadmill was elevated during CWT, with VO2 being lowered relative to HR. Mean VE and La values were 52.7 (+/- 14.5) l.min-1 and 6.9 (+/- 3.6) mM. The effect of the same CWT regimen on spinal loading as indicated by change in stature (shrinkage) was investigated in a second study (n = 8). The mean (+/- SD) time taken to complete the circuit was 17.4 (+/- 1.3) min. Mean shrinkage due to CWT (2.5 +/- 1.5 mm) was unrelated to the time taken to complete the circuits, to HR, RPE or to low back pain ratings (p > 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)