Abstract
Objective: Decreased lower muscle flexibility and increased joint laxity, which are affected by bone growth, are considered intrinsic risk factors of sports injuries in adolescent players. However, little is known about changes in lower muscle flexibility and joint laxity at around age of peak height velocity (APHV).
Purpose: To examine the characteristics of lower muscle flexibility and joint laxity at around APHV in male soccer players.
Methods: Thirty-three adolescent soccer players participated in this cross–sectional study. Eligibility criteria included a) availability of height data from 4th grade of elementary school to 1st grade of junior high school and b) no pain throughout the body. Muscle flexibility of the hamstrings, quadriceps, and gastrocnemius was measured. Joint laxity was measured using the general joint laxity test. APHV was calculated based on the date height was measured. Maturity status was defined as the difference between actual age and APHV. Based on maturity status, participants were divided into three groups (G1: actual age ≤6 months before APHV, G2: actual age ≤6 months after APHV, G3: actual age 6-12 months after APHV)
Results: Flexibility of the gastrocnemius in the G1 group (–1.7 ± 4.3°) was significantly lower than in the G2 group (3.8 ± 5.3°), and the G1 group had significantly lower joint laxity (1.8 ± 1.0 points) than the G3 group (3.3 ± 1.3 points).
Conclusion: Our results suggest that muscle flexibility of the gastrocnemius and joint laxity before APHV were lower than those after APHV.
