Breast Support Alters Knee Joint Biomechanics During A Landing Task.

Abstract

Females have a greater rate of traumatic knee injuries than male athletes. Trunk position has been shown to affect knee joint biomechanics during a landing task. Given the position of breast tissue, insufficiently supported breasts may also alter knee joint biomechanics. However, no previous research has investigated the effect of breast tissue or support on knee joint biomechanics during landing. PURPOSE: to determine the effect of breast support on knee and hip joint kinetics during a landing task. METHODS: Fifteen female athletes performed five step-off landings from a height of 40 cm in each of three bra support conditions: control (CON), low support (LOW) and high support (HIGH). 3D kinematics and ground reaction forces (GRFs) were simultaneously recorded using a 9-camera motion capture system (240 Hz,) and pair of force platforms (1200 Hz,)..) was used to calculate knee and hip joint angles and moments. Custom software (was used to determine peak joint angles and moments. Repeated measures ANOVAs with Tukey’s post-hoc analyses were used to compare mean knee and hip joint kinetics. RESULTS: No differences in peak knee abduction moments were observed, though peak knee external rotation moments were smaller in the LOW compared to CON (p = 0.007) and HIGH conditions (p = 0.013). No differences were observed between CON and HIGH (p = 0.423). No differences were observed in peak hip abduction moment or peak hip external rotation moment. CONCLUSIONS: These findings indicate that knee joint biomechanics during a landing task are affected by breast support. The current study did not address the role of trunk orientation or differences in breast size amongst participants. Future research should address the role of breast motion on trunk kinematics and kinetics.Table 1: Mean knee and hip joint moments in the CON, LOW and HIGH support conditions.