Could the deleterious effect of stretching only influence soccer players with better performance in the vertical jump?

Purpose
The aim of the study was to investigate the acute effects of high vs. low volume stretching exercises on vertical jump in youth male soccer players and verify if different performances at baseline could exert any influence on these effects.

Methods
Overall, 45 players (mean age, 14.0 ± 0.7 years) from the 1st division of Rio de Janeiro state championship were invited to participate in the study. They were assessed for vertical jump and stretching over 3 days. On day 1, they were tested for vertical jump after a conventional warm-up. On day 2, the group was randomly divided into 2 subgroups: one subgroup tested for vertical jump after low-volume stretching and the other subgroup tested for vertical jump after high-volume stretching. On day 3, a counterbalanced order of the stretching protocol was employed. Then, the baseline vertical jump scores were stratified in terciles to compare the effect of high-volume stretching between the groups.

Results
After high-volume stretching, a significant decrease in vertical jump was detected (–25.8%; p = 0.01; partial η² = 0.63), while no differences were observed for low-volume stretching. Moreover, players with better performance in vertical jump (1st tercile) demonstrated a greater reduction in jumping height after high-volume stretching than those of the 3rd tercile (1st vs. 3rd tercile: –41.1 ± 3.6% vs. –21.7 ± 6.9; p < 0.05).

Conclusions
The results suggest that players with best vertical jump performance can be more sensitive to the alterations in muscle inhibition after high-volume stretching exercises.