 The intervention for both groups consisted of 12 weeks of two weekly training sessions, with at least 48 hours of interval between sessions. The HIRT performed the squat, deadlift and lunge exercises, as these exercises induce high core muscles activity. HIRT started with two weeks of low intensity exercises emphasizing the activation of core muscles pelvic elevation with feet on the floor, superman, static supine bridge on bosu, and the technique of the selected resistance exercises e.g. squat, deadlift, and lunges. Participants performed 3 sets of 10 repetitions per exercise. In the third and forth weeks, participants performed the exercises from the previous weeks and also static unipedal forward flexion on bosu and dynamic unipedal forward flexion and the main exercises with a load corresponding to 50 of the 1 RM load Brzycki, 1993.This formula is applied in a test that the subject is encouraged to perform the maximal number of repetitions possible with a predetermined load. The chosen load must allow the subject to achieve a maximum of ten repetitions, which guarantee a good RM prediction. The weight lifted and repetitions performed are applied in the equation to calculate the 1 RM estimation. 