Effects of Elastic-Band Resistance and Plyometric Training on Serum MMP-2, MMP-9, TIMPs and Coenzyme Q10 in Collegiate Tennis Players: An Exploratory, Non-Randomised Three-Arm Controlled Study

Background/Objectives: Elastic-band resistance and plyometric training, which differ in eccentric and impact loading, are commonly added to tennis conditioning, but their effects on circulating markers related to extracellular-matrix turnover and antioxidant status are unknown. Methods: In this exploratory, matched, non-randomised controlled study, 24 collegiate tennis players (11 women, 13 men) were allocated to habitual tennis training only (CON) or to 8 weeks of additional elastic-band resistance (RBT) or plyometric training (PLY); 23 (CON 8, RBT 7, PLY 8) were analysed. Fasting serum MMP-2, MMP-9, TIMP-1, TIMP-2 and coenzyme Q10 (CoQ10) were measured by enzyme-linked immunosorbent assay (ELISA) approximately 24 h after the final session and compared by baseline-adjusted analysis of covariance with multiplicity control and sensitivity analyses. Results: Baseline-adjusted CoQ10 was lower in RBT than in CON (Hedges’ g −0.86, 95% CI −1.47 to −0.26) and PLY (g −0.80, 95% CI −1.48 to −0.12); in RBT, CoQ10 fell from 16.6 ± 4.3 to 8.3 ± 1.9 ng/mL. Adjusted TIMP-1 was lower in both training groups than in CON, reflecting an increase in CON rather than a decrease with training. TIMP-2 was lower in RBT than in CON and PLY (g −1.00 and −1.10), but this was not confirmed by rank-based analysis. MMP-9 fell over time in all groups without a group effect, and MMP-2 was unchanged. Conclusions: In this small, non-randomised study, adding elastic-band training to tennis practice was associated with lower serum CoQ10 and, less robustly, TIMP-2; plyometric training was not associated with changes beyond those seen in all groups, although only very large effects were detectable. These hypothesis-generating findings require confirmation in adequately powered randomised trials using chromatographic CoQ10 measurement.