Background Despite numerous injury prevention programs (IPP), the incidence of anterior cruciate ligament (ACL) in athletics remains high. Few IPP have quantified biomechanical changes in the dominant and non-dominant leg.

Objective To evaluate the effects of an IPP on lower extremity (LE) biomechanics between dominant and non-dominant limb during an unanticipated sidestep cutting task (USCT).

Design Quasi-experimental.

Setting Collegiate soccer players.

Participants 14 athletes (19.1±1.0 years, 1.67±0.05 m, 63.6±6.0 kg) free from any LE injury six months prior to and throughout the study, and with team physician clearance to practice and play participated in the study.

Risk factor assessment A 3-D motion-capture system quantified LE biomechanics pre and post IPP during an USCT. Participants completed 3 USCT trials bilaterally. The IPP integrated agility and plyometric drills into normal team training during a 10-week off-season period. The IPP emphasized maximum effort and power while maintaining proper body angles and force attenuation during landing, as well as during acceleration and jumping.

Main outcome measurements Hip (HF) and knee flexion (KF) and abduction angles(°) and moments (Nm/kgm) were measured at initial contact [IC] and peak stance [PS]. Repeated measures ANOVAs assessed the effects of training and leg dominance.

Results At IC, KF decreased on the dominant side post-IPP (Pre: -26±8, Post: −19±8, p=0.045). Knee adductor moment decreased post-IPP on dominant side (Pre: 0.11±0.11, Post: −0.01±0.10, P=.012), but the non-dominant side increased post-IPP (Pre: 0.04±0.12, Post: 0.09±0.11, P=.012). HF decreased for both sides post-IPP (P=.006), whereas hip flexor moment increased (P=.025). At PS, HF decreased post-IPP (P=.0017) regardless of side. No other differences were noted.

Conclusions After a 10-week IPP, participants decreased knee and hip flexion angles regardless of limb dominance. Our participants exhibited similar movement patterns between the dominant and non-dominant leg. Our findings also suggest that when IPP drills focus on power and body posture, its effectiveness to alter neuromechanics relative to non-contact ACL injury risk factors remains questionable and warrants further investigation.