Background: A main goal of programming is to structure the optimal variations in training factors to optimize athletes' adaptations. Nevertheless, it remains unknown the optimal programming model leading to greater neuromuscular adaptations. Purpose: The aim of the present study was to assess the influence of three different magnitudes of variability within resistance training programs on performance adaptations. Methods: Forty participants were assigned to three different groups differing in the frequency of change in training contents: a weekly model (WM; n = 12), a daily model (DM; n= 14), and a session model (SM; n = 14). The training intervention lasted for six weeks, performing two sessions per week of back-squat exercise. Total training load (volume and intensity) of the six-week intervention was equated for all groups. Maximum dynamic strength (1RM) in the back-squat, countermovement (CMJ) and squat jump (SJ) were measured pre- and post-training intervention. Results: All groups showed significant increases (p< .05) in 1RM, with the SM showing greater increases than the WM (20.5 vs 13.6%; p= .022). Although not reaching statistical significance, the magnitude of the increases in CMJ tended to be greater for DM and SM group (9.5% and 8.1%, respectively,) than in the WM (4.4%). All groups showed similar increases in the SJ (7.7-9.9%). Conclusions: The results of the present study suggest that the use of more frequent stimuli variations within resistance training programming is a key factor to achieve concomitant increases in strength and jumping performance.
Keywords: Programming; resistance training; strength; variability.