Context: Single-sport specialization (SSS) is becoming more prevalent in youth athletes. Deficits in functional movement have been shown to predispose athletes to injury. It is unclear whether a link exists between SSS and the development of functional movement deficits that predispose SSS athletes to an increased risk of knee injury.
Objective: To determine whether functional movement deficits exist in SSS athletes compared with multi-sport (M-S) athletes.
Design: Cross-sectional study.
Setting: Soccer practice fields.
Patients or other participants: A total of 40 (21 SSS [age = 15.05 ± 1.2 years], 19 M-S [age = 15.32 ± 1.2 years]) female high school athlete volunteers were recruited through local soccer clubs. All SSS athletes played soccer.
Intervention(s): Participants were grouped into 2 categories: SSS and M-S. All participants completed 3 trials of the standard Landing Error Scoring System (LESS) jump-landing task. They performed a double-legged jump from a 30-cm platform, landing on a rubber mat at a distance of half their body height. Upon landing, participants immediately performed a maximal vertical jump.
Main outcome measure(s): Values were assigned to each trial using the LESS scoring criteria. We averaged the 3 scored trials and then used a Mann-Whitney U test to test for differences between groups. Participant scores from the jump-landing assessment for each group were also placed into the 4 defined LESS categories for group comparison using a Pearson χ(2) test. The α level was set a priori at .05.
Results: Mean scores were 6.84 ± 1.81 for the SSS group and 6.07 ± 1.93 for the M-S group. We observed no differences between groups (z = -1.44, P = .15). A Pearson χ(2) analysis revealed that the proportions of athletes classified as having excellent, good, moderate, or poor LESS scores were not different between the SSS and M-S groups ([Formula: see text] = 1.999, P = .57).
Conclusions: Participation in soccer alone compared with multiple sports did not affect LESS scores in adolescent female soccer players. However, the LESS scores indicated that most female adolescent athletes may be at an increased risk for knee injury, regardless of the number of sports played.
Keywords: injuries; knee; movement assessment.