Effects of Six-Week Pre-Season Complex Contrast Training Intervention on Male Soccer Players' Athletic Performance

Introduction. This study aimed to investigate the effects of a six-week complex contrast training (CCT) intervention on the athletic performance of highly-trained amateur male soccer players during the pre-season period. Material and Methods. Participants aged 21.3 were randomized to CCT (n = 7) or active (i.e. standard soccer training) control (CG; n = 9) groups. Athletic performance was assessed using the 30 m linear sprint test time, standing long jump distance (SLJ), countermovement jump (CMJ) height, and unilateral right-left knee flexion and extension isokinetic maximal strength tests. The experimental group replaced part of the standard soccer training schedule with three CCT sessions per week for six weeks. A two (pre-post intervention) by two (CCT, CG) mixed ANOVA was used to analyze the exercise-specific effects. In addition, between-group comparisons at post-test were conducted with baseline scores as covariate. Within group changes were analyzed using paired t-test. Results. Significant group-by-time interaction effects were found for all dependent variables (p < 0.001 - 0.004). Post-hoc tests using paired t-test revealed significant improvements in all dependent variables in CCT (all p ≤ 0.001; effect size (g) = 0.29 - 0.96; %Δ= 4.5 - 14.7), but not in CG (p = 0.174 - 0.633; g = 0.03 - 0.20; %Δ= 0.4 - 2.6). Further, Bonferroni adjusted post-hoc analysis using baseline scores as a covariate showed post-test differences in favor of CCT compared to CG for all variables. Conclusions. CCT is recommended as an effective training strategy during the pre-season to improve athletic performance among highly-trained amateur male soccer players.