Circuit training without external load induces hypertrophy in lower-limb muscles when combined with moderate venous occlusion

The present study investigated whether circuit training with body weight alone (no external load) can cause muscular hypertrophy when combined with moderate venous occlusion (‘Kaatsu Training’). Healthy women (mean age, 32.7 ± 4.0 yr; n=22) were randomly assigned into the occlusive training group (OCC, n=11) and the normal training group (NOR, n=11). Both groups performed the same circuit-training regimen consisting of six, successive exercises for muscles in the upper and lower limbs and the trunk, at a frequency of 3 sessions/wk. Each session lasted for 5-10 min. In OCC group, proximal ends of the upper and lower limbs of both sides were moderately compressed by means of ‘KAATS Sportswear’, to restrict the venous blood flow during the exercises (preset pressure, 50-80 mmHg and 80-120 mmHg for upper and lower limbs, respectively). Cross-sectional area (CSA) of the thigh muscle was measured with spiral computer tomography. After an 8-wk period of training, the muscle CSA of both right and left limbs showed significant increases by ∼3% (P