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RESEARCH PRODUCT

Step vs. Two-Phase Gradual Volume Reduction Tapering Protocols in Strength Training: Effects on Neuromuscular Performance and Serum Hormone Concentrations.

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ABSTRACT Seppanen, S and Hakkinen, K. Step vs. two-phase gradual volume reduction tapering protocols in strength training: Effects on neuromuscular performance and serum hormone concentrations. J Strength Cond Res XX(X): 000-000, 2020-This study assessed effects of 2 reduced volume tapering protocols on neuromuscular performance and serum hormone concentrations in 14 recreationally strength-trained men (21-30 years). After an 8-week strength training period subjects were divided to the step (54% volume reduction immediately) and 2-phase gradual (38% reduction for the first week and 70% for the second week) tapering groups for 2 weeks. One repetition maximum (1RM) squat, maximal isometric bilateral leg press force (leg press MVIC), electromyography (EMG) of vastus lateralis (VL) and vastus medialis, cross-sectional area of VL, serum testosterone, cortisol, and sex hormone-binding globuline (SHBG) concentrations were measured before and repeatedly during training and tapering periods. Both tapering protocols led to significant increases (p < 0.01) in squat 1RM. However, the increase in the step group (3.4 ± 2.1%) was higher (p < 0.05) than in the gradual group (1.7 ± 0.9%). The maximal integrated EMG of VL increased (p < 0.05) during tapering in the step group. Serum testosterone concentration increased (p < 0.05) and T/SHBG ratio reached the highest level after 1-week tapering in the step group. In the gradual group, T/SHBG ratio was (p < 0.05) higher after the taper than after the training period. Individual changes in T/SHBG ratio in the total group correlated positively (p < 0.05) with individual changes in leg press MVIC during the taper. These results suggest that reducing training volume can be an effective way to peak maximal strength. However, a higher volume reduction rate at the beginning of taper seems to lead to more favorable changes in maximal strength accompanied by positive changes in the neuromuscular system and serum hormone concentrations when taper follows an overreaching period.