Breast support implications for larger-breasted females during vertical jumping

Considerable multi-planar breast movement has been reported during jumping, yet the effect of breast support on landing kinematics and kinetics during vertical jumping has not been investigated. Preliminary research has suggested alterations in running kinematics and kinetics can occur as a result of differing magnitudes of breast movement. Examining relationships between breast movement and the vertical jump landing strategy will increase our understanding of the breast support implications for larger-breasted athletes during sport and exercise. The aim was to assess relationships between multi-planar breast kinematics and landing strategy during vertical jumping.Twelve larger-breasted (UK breast cup sizes D to E) active females (mean (SD): age 24 (4) years, height 1.66 (0.07) m, body mass 69.58 (12.26) kg) completed six maximum effort non-consecutive two-footed vertical countermovement jumps in an everyday bra (low support) and a sports bra (high support) on a force platform (1000 Hz; Kistler, Switzerland). Three-dimensional relative breast kinematics and sagittal plane kinematics were monitored using eight infrared Oqus cameras (200 Hz; Qualisys, Sweden). In both breast support conditions multi-planar breast kinematics during the first half of the jump were correlated to kinetic variables and sagittal plane kinematics during the landing phase.Multi-planar breast displacement, velocity and acceleration were significantly lower in the high support condition (p < 0.017). Jump height (mean 0.27 m in both conditions) was not affected by breast support. Increased vertical breast displacement during the first half of the jump decreased the mediolateral ground reaction force upon landing (r = -0.508, p = 0.022). Increases in anterioposterior breast kinematics related to increased thorax, thigh and knee flexion at initial contact (r = 0.564 to 0.607; p < 0.04). It could be speculated that when participants felt less supported they attempted to increase their base of support on landing, subsequently increasing stability. Increased flexion on landing with increased breast movement may be a strategy selected to reduce landing forces. Results suggest participants may have consciously employed a more flexed and stable landing strategy when breasts were less supported by increasing joint flexion and reducing mediolateral ground reaction forces. This may have been a pre-planned landing strategy or a result of increased breast kinematics during the first half of the jump. Future research should investigate the performance implications of this altered landing strategy on subsequent movements, although high breast support for larger-breasted athletes during jumping is recommended to reduce breast kinematics.