CHANGING HAND POSITIONS ALTERS LOWER EXTREMITY BIOMECHANICS DURING LANDING

Background During gameplay, athletes frequently change their trunk and hand placement positions (e.g. ball handling). Changing trunk positions alters lower extremity (LE) biomechanics and subsequent injury risk during sport. However, whether changing hand positions also alters LE biomechanics during landing (a high LE injury-risk activity) is unclear. Objective To examine if changing hand positions during landing affects LE biomechanics. Design Repeated measures. Setting Laboratory. Participants 30 healthy participants (23.4±4.3 years, 170.7±7.7 cm, 70.2±18.9 kg). Interventions Participants performed 5 landings from a 45cm box in 4 different hand placement (HP) conditions: 1) Holding a basketball at chest level (CH), 2) Holding a basketball at chest with arms straight in front (FR), 3) Holding a basketball straight up over head (UP), and 4) Placing hands on hips (HIP). Main outcome measurements Sagittal hip, knee, ankle angles (°) from initial touchdown to lowest point of the vertical Center of Mass (COM min) displacement were assessed using 3-D motion analyses. Repeated measures ANOVAs and Bonferroni pairwise comparisons examined differences across HP conditions. Results At touchdown, participants had differing hip (P