(1) Background: Change of direction (COD) is crucial for agility in team sports. Complex contrast training (CNT), alternating between heavy and light exercises, is a newer method currently gaining attention, but its effectiveness compared to others (strength training, ST; plyometric training, PT; complex descending training, DT; complex ascending training, AT) is unclear. (2) Methods: A systematic review and meta-analysis following PRISMA guidelines included studies with CNT interventions. The effect size (ES) was measured using Hedges’ g, with subgroup analyses for moderating factors. (3) Results: CNT improved COD performance more than PT (ES = 0.65), ST (ES = 0.88), and controls (ES = 1.24), with no significant difference from DT (ES = −0.08) or AT (ES = 0.19). CNT was particularly effective for athletes under 18 (ES = 1.13), females (ES = 1.59), amateurs (ES = 1.02), and COD measures with more than three turns (ES = 1.08). (4) Conclusions: CNT enhances COD performance, proving superior to standalone strength or plyometric training. However, its effectiveness is comparable to other combined-training models, suggesting that the integration of high-load strength and high-velocity power exercises is the primary driver of adaptation. The benefits are most pronounced in younger, female, and amateur athletes. Future large-scale studies are needed to confirm these findings and refine protocols for diverse populations.

Propulsive power is one of the factors that determine the performance of sprint cycling. Pedaling rate is related to power output, and stiffness is associated with improving performance in athletic tasks. Purpose: to investigate the relationship between musculoarticular stiffness and pedaling rate. Methods: twenty-two healthy, untrained male volunteers (19 ± 2 years, 175 ± 6 cm, 74 ± 16 kg) were divided into two groups after their musculoarticular (MA) stiffness was tested, and these groups were the stiffness group (SG) and compliant group (CG). A 6-s maximal cycling test was conducted in four cycling modes, which were levels 5 and 10 air-resistance, and levels 3 and 7 magnetic-resistance. Peak and average cadence, peak power output (PO_peak), crank force (CF_peak), peak rate of crank force development (RCFD), and the angle of peak crank force were collected. The significance of differences between the two groups for these variables was assessed using an independent samples t-test. Pearson product–moment correlations were calculated to analyze the relationship between MA stiffness and each performance variable. Results: the SG had significantly higher peak cadence and average cadence at level 3 magnetic-resistance, peak crank force, and peak power output at level 10 air-resistance, peak rate of crank force development at levels 5 air-resistance, 10 air-resistance, and 3 magnetic-resistance (p < 0.05). MA stiffness was significantly correlated with average cadence at levels 5 and 10 air-resistance, peak crank force in all 4 modes, and RCFD and peak power output at level 10 air-resistance. There were no significant relationships between MA stiffness and the angle of peak crank force in each cycling mode. Conclusion: results indicate that participants with relatively higher MA stiffness seemed to have a higher pedaling rate during a 6-s sprint cycling in these conditions. They also performed a superior crank force and rate of crank force development, producing greater power output when sprint cycling. Optimizing cycling resistance or gear ratio to enhance both RCFD and musculotendinous stiffness may be crucial for improving sprint cycling performance.