Effects of Six Weeks of Depth Jump vs. Countermovement Jump Training on Sand on Muscle Soreness and Performance

The purpose of this study was to examine the effects of six weeks of depth jump (DJ) vs. countermovement jump (CMJ) training on sand on muscle soreness, jump, sprint, agility and leg press strength. Thirty healthy men (age 20.4±1.1 years; height 177.4±5.1 cm; mass 72.8±9.7 kg) volunteered to participate and were randomly assigned to one of three groups: DJ training group (n=10), CMJ training group (n=10) or control group (n=10). The experimental groups performed either DJ or CMJ training two days a week for six weeks. The training program included five sets of 20 repetitions DJ (from the height of a 45-cm box) or CMJ exercise onto 20 cm of dry sand. Assessments of Vertical Jump Test (VJT), Standing Long Jump Test (SLJT), 20 and 40 m sprints, T-Test (TT), Illinois Agility Test (IAT), and one-repetition maximum Leg Press (1RMLP) were performed a week before and following the 6-week training period. Muscle soreness was also measured pre, immediately post, 24 and 48 hours after the first and last training sessions. Significant increases were observed in both the DJ and CMJ groups in VJT (16.2 vs. 13.5%), and SLJT (13.9 vs. 14.4%) (p<.05). Significant decreases in 20 and 40 m sprint times, TT and IAT were observed in both groups (20 m: 8.5 vs. 7.4%; 40 m: 6.1 vs. 3.8%; TT: 9.3 vs. 12%; IAT: 9.2 vs. 10.6% in DJ and CMJ groups, respectively). Only the CMJ group made significant improvements in 1RMLP (p<.05). The CMJ group had significantly greater perception of muscle soreness than the DJ and CG groups in the rectus femoris at 48 hours post the first training session (p<.05). No significant differences were observed among groups in muscle soreness after the last training session (p>.05). These observations may have considerable practical relevance for the optimal design of plyometric training programs, given that DJ and CMJ training on sand is effective for improving muscular performance.