Influence of lifting technique on perceptual and cardiovascular responses to submaximal repetitive lifting

Oxygen consumption (VO2), heart rate, ventilation and central rating of perceived exertion (RPE) in repetitive lifting while executing squat and stoop techniques were investigated in ten male forestry workers. In all five mass/frequency combinations studied, VO2 was significantly higher for the squat than for the stoop technique. No differences were found in RPE between the techniques. The VO2 and RPE recordings were also related to those obtained during maximal repetitive lifting (same lifting technique) and maximal treadmill running. The VO2 expressed as a percentage of that obtained during maximal repetitive lifting with the same lifting technique was defined as relative aerobic intensity (% VO2max,lifting). The % VO2max,lifting was not significantly different between the techniques except for the lowest mass lifted (1 kg). This study therefore would support the hypothesis that RPE is more closely related to % VO2max,lifting than to absolute aerobic intensity. Related to maximal treadmill running, it was demonstrated for both lifting techniques that relative RPE (percentage of the RPE during maximal running) was more accurate than relative VO2 (percentage of maximal VO2 during maximal running) for determining the % VO2max,lifting in repetitive lifting. The study showed that the higher VO2 during squat lifting compared to stoop lifting was caused by the VO2 expended in lifting and lowering the body rather than the VO2 expended lifting and lowering the external mass. It was concluded that the stoop technique was not superior to the squat technique in terms of central RPE. Based on % VO2max,lifting, there may be a rationale for choosing the stoop technique during repetitive lifting with light masses, but not with heavy masses.