Basketball Players Jump and Maximal Strength Performance Improvements After French Contrast Training

(1) Background: French contrast training (FCT) enhances sports performance, but its long-term efficacy in elite basketball players remains unclear. This study compared FCT and traditional strength training (TST) on jump performance and lower-limb strength. (2) Methods: Sixteen elite basketball players (age 22.4 ± 1.4 years; 14 male, 2 female) were randomly assigned to 8 weeks of FCT (n = 8) or TST (n = 8). The TST protocol consisted of barbell back squat, barbell Bulgarian split squat, conventional deadlift, and barbell hip thrust (4 sets of 8, 6, 4, 4 repetitions at 80%, 95%, 90%, 90% of one-repetition maximum [1RM]; 2–3 min inter-set rest). Assessments included countermovement jump (CMJ) kinetics, CMJ with arm swing (CMJA), running CMJ, running single-leg CMJ, and back squat 1RM, analyzed via repeated-measures ANOVA. (3) Results: A significant Group × Time interaction favored FCT for maximal relative force (p = 0.007, ηp2 = 0.41): FCT increased 6.80% (Cohen’s d = 1.55), TST decreased 2.41% (d = −0.36). Significant time effects (p < 0.001–0.044) occurred for CMJA, running CMJ, flight height, reactive strength index, and back squat 1RM, with large improvements in both groups (e.g., back squat 1RM: FCT +30.45%, d = 2.89; TST +26.77%, d = 2.34). The interaction for average power approached significance (p = 0.053, ηp2 = 0.24). No other interactions were significant. (4) Conclusions: Both FCT and TST improved performance, but FCT yielded superior gains in maximal relative force. Limitations include small sample (n = 16), mixed-gender composition, short 8-week intervention, and lack of retention testing.