Effects of an eight-week French contrast training program on lower-limb explosive power, acceleration, and muscle strength in male college badminton players

Background Badminton is a high-intensity sport that demands lower-limb athletic performance. French Contrast Training (FCT), which combines heavy compound exercises, plyometrics, light to moderate loads, and assisted plyometric movements in one session, has been suggested to enhance neuromuscular adaptations more effectively. However, the efficacy of FCT on lower-limb explosive power, acceleration, and muscle strength compared to equal-load training (ELT) in badminton players remains unclear. Objective This study aims to investigate the effects of an eight-week FCT program on lower-limb explosive power, acceleration, and muscle strength compared to ELT in college badminton players. Methods Thirty male college badminton players were randomly assigned to the FCT group (n=15) or the ELT group (n=15). Both groups completed an eight-week (twice a week) training program. The FCT protocol consisted of four sequential exercises per session: 80% 1RM back squat, 30cm hurdle jump, 30% 1RM barbell squat jump, and band-assisted jump. The control group performed ELT, an isolated method that involved exercises with loads aligned to FCT. Outcomes measurement before and after training included countermovement jump (CMJ), squat jump (SJ), 10-meter sprint time, maximal velocity (V max ), maximal acceleration (A max ), 1RM back squat, and mean concentric velocity (MCV) from 20% to 80%1RM. We used two-way repeated measures analysis of variance (ANOVA) (time × group) with Bonferroni post hoc tests, and effect sizes were reported as partial eta squared ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="im1"> <mml:mrow> <mml:msubsup> <mml:mstyle mathvariant="bold" mathsize="normal"> <mml:mi>η</mml:mi> </mml:mstyle> <mml:mstyle mathvariant="bold" mathsize="normal"> <mml:mi>p</mml:mi> </mml:mstyle> <mml:mn>2</mml:mn> </mml:msubsup> </mml:mrow> </mml:math> ). p&amp;lt; 0.05 was statistically significant. Results FCT yielded greater improvements than ELT in CMJ (p&amp;lt; 0.001, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="im2"> <mml:mrow> <mml:msubsup> <mml:mstyle mathvariant="bold" mathsize="normal"> <mml:mi>η</mml:mi> </mml:mstyle> <mml:mstyle mathvariant="bold" mathsize="normal"> <mml:mi>p</mml:mi> </mml:mstyle> <mml:mn>2</mml:mn> </mml:msubsup> </mml:mrow> </mml:math> = 0.621), SJ (p&amp;lt; 0.001, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="im3"> <mml:mrow> <mml:msubsup> <mml:mstyle mathvariant="bold" mathsize="normal"> <mml:mi>η</mml:mi> </mml:mstyle> <mml:mstyle mathvariant="bold" mathsize="normal"> <mml:mi>p</mml:mi> </mml:mstyle> <mml:mn>2</mml:mn> </mml:msubsup> </mml:mrow> </mml:math> = 0.849), 10-meter sprint time (p&amp;lt; 0.001, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="im4"> <mml:mrow> <mml:msubsup> <mml:mstyle mathvariant="bold" mathsize="normal"> <mml:mi>η</mml:mi> </mml:mstyle> <mml:mstyle mathvariant="bold" mathsize="normal"> <mml:mi>p</mml:mi> </mml:mstyle> <mml:mn>2</mml:mn> </mml:msubsup> </mml:mrow> </mml:math> = 0.853), V max (p&amp;lt; 0.001, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="im5"> <mml:mrow> <mml:msubsup> <mml:mstyle mathvariant="bold" mathsize="normal"> <mml:mi>η</mml:mi> </mml:mstyle> <mml:mstyle mathvariant="bold" mathsize="normal"> <mml:mi>p</mml:mi> </mml:mstyle> <mml:mn>2</mml:mn> </mml:msubsup> </mml:mrow> </mml:math> = 0.638), A max (p&amp;lt; 0.001, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="im6"> <mml:mrow> <mml:msubsup> <mml:mstyle mathvariant="bold" mathsize="normal"> <mml:mi>η</mml:mi> </mml:mstyle> <mml:mstyle mathvariant="bold" mathsize="normal"> <mml:mi>p</mml:mi> </mml:mstyle> <mml:mn>2</mml:mn> </mml:msubsup> </mml:mrow> </mml:math> = 0.820), and MCV from 20 to 40% 1RM (p&amp;lt; 0.001, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="im7"> <mml:mrow> <mml:msubsup> <mml:mstyle mathvariant="bold" mathsize="normal"> <mml:mi>η</mml:mi> </mml:mstyle> <mml:mstyle mathvariant="bold" mathsize="normal"> <mml:mi>p</mml:mi> </mml:mstyle> <mml:mn>2</mml:mn> </mml:msubsup> </mml:mrow> </mml:math> = 0.615; p&amp;lt; 0.001, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="im8"> <mml:mrow> <mml:msubsup> <mml:mstyle mathvariant="bold" mathsize="normal"> <mml:mi>η</mml:mi> </mml:mstyle> <mml:mstyle mathvariant="bold" mathsize="normal"> <mml:mi>p</mml:mi> </mml:mstyle> <mml:mn>2</mml:mn> </mml:msubsup> </mml:mrow> </mml:math> = 0.697). However, no significant differences were found between the groups for the 1RM back squat (p = 0.218, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="im9"> <mml:mrow> <mml:msubsup> <mml:mstyle mathvariant="bold" mathsize="normal"> <mml:mi>η</mml:mi> </mml:mstyle> <mml:mstyle mathvariant="bold" mathsize="normal"> <mml:mi>p</mml:mi>