Different exercise training interventions and drop-landing biomechanics in high school female athletes.

CONTEXT: Anterior cruciate ligament (ACL) injuries are common in female athletes and are related to poor neuromuscular control. Comprehensive neuromuscular training has been shown to improve biomechanics; however, we do not know which component of neuromuscular training is most responsible for the changes.

OBJECTIVE: To assess the efficacy of either a 4-week core stability program or plyometric program in altering lower extremity and trunk biomechanics during a drop vertical jump (DVJ).

DESIGN: Cohort study.

SETTING: High school athletic fields and motion analysis laboratory.

PATIENTS OR OTHER PARTICIPANTS: Twenty-three high school female athletes (age = 14.8 ± 0.8 years, height = 1.7 ± 0.07 m, mass = 57.7 ± 8.5 kg).

INTERVENTION(S): Independent variables were group (core stability, plyometric, control) and time (pretest, posttest). Participants performed 5 DVJs at pretest and posttest. Intervention participants engaged in a 4-week core stability or plyometric program.

MAIN OUTCOME MEASURE(S): Dependent variables were 3-dimensional hip, knee, and trunk kinetics and kinematics during the landing phase of a DVJ. We calculated the group means and associated 95% confidence intervals for the first 25% of landing. Cohen d effect sizes with 95% confidence intervals were calculated for all differences.

RESULTS: We found within-group differences for lower extremity biomechanics for both intervention groups (P ≤ .05). The plyometric group decreased the knee-flexion and knee internal-rotation angles and the knee-flexion and knee-abduction moments. The core stability group decreased the knee-flexion and knee internal-rotation angles and the hip-flexion and hip internal-rotation moments. The control group decreased the knee external-rotation moment. All kinetic changes had a strong effect size (Cohen d > 0.80).

CONCLUSIONS: Both programs resulted in biomechanical changes, suggesting that both types of exercises are warranted for ACL injury prevention and should be implemented by trained professionals.