Author(s): MERINO PÉREZ, J., SÁNCHEZ-VALDEPEÑAS, J., PÁEZ-MALDONADO, J.A., GALLO-HIDALGO, J.M., JIMÉNEZ-ROLDÁN, M.J., SÁNCHEZ-MORENO, M., CORNEJO-DAZA, P.J., PAREJA-BLANCO, F., Institution: UNIVERSIDAD PABLO DE OLAVIDE, Country: SPAIN, Abstract-ID: 1260

INTRODUCTION:
Velocity loss (VL) is established as a valid indicator to determine the level of effort attained during resistance training (RT) (1). In long-term adaptations, it is well known that a low-to-moderate VL threshold optimizes strength gains and vertical jump performance (2). However, there are no available data on the residual effects of VL on strength gains after a detraining period. Therefore, the aim of this study was to compare the effects of two RT programs with different VL thresholds (i.e., 20% vs. 40%) on strength gains and jump performance after an RT intervention and a detraining period.
METHODS:
Forty-four physically active men followed an 8-week RT program based on the full-squat (SQ) exercise (16 sessions). Subjects were randomly allocated into the two intervention groups that differed in the VL attained within the set (VL20: 20%; VL40: 40%). The relative intensity (65-80% 1-RM), inter-set recovery (4 minutes), and number of sets (3) were matched for both groups in each training session. The performance was evaluated on three occasions: pre-training (PRE), post-training (POST), and after 3 weeks of the detraining period (DET). The following battery of tests was performed in each testing session in the subsequent order: 1) countermovement jump (CMJ), 2) progressive loading SQ test, and 3) fatigue SQ test. The performance variables were: 1) CMJ height; 2) 1RM; 3) mean propulsive velocity (MPV) achieved with the common absolute loads performed at PRE (AV); 4) MPV achieved with the common absolute loads lifted faster than 1 m·s-1 at PRE (AV≥1), 5) MPV achieved with the absolute loads displaced slower than 1 m·s-1 at PRE (AV<1), 6) number of repetitions completed in the fatigue test (MNR).
RESULTS:
Significant main “time” effects were found for all performance variables analysed. However, no significant “group x time” interactions were observed. Both groups significantly improved strength performance against different loads (i.e., 1RM, AV, AV≥1, and AV<1), without significant differences between them. Only VL40 significantly increased CMJ height at POST (p = 0.002). Likewise, VL40 achieved significantly higher performance in AV, AV≥1, CMJ, and MNR than VL20 at DET
CONCLUSION:
Despite the VL40 experiencing a higher level of effort within the set, both groups achieved similar strength-derived adaptations after an RT intervention. However, the VL40 group maintained better strength and jump performances after a detraining period, suggesting that accumulating higher volume and fatigue levels during an RT intervention could result in longer residual benefits on strength performance.