Randomness and complexity of breast motion

Reductions in breast motion from wearing bras have been demonstrated, but relating reductions to subject perceptions of bra effectiveness or correlating reduction to breast size has met minimal success. These shortcomings suggest breast motion, and interaction is not adequately understood. This study’s purpose was to use Recurrence Quantification Analysis to describe non-linear dynamic properties of breast motion while 30 females performed jumping jacks in natural and high and low support conditions. Differences in RQA measures between support conditions and control suggest support reduces predictability of breast motion as the motion becomes more random and less dominated by large amplitude and lower frequency oscillations. The motion is more disordered for unsupported than for supported breasts, and the degree of support reduces the complexity. RQA shows potential for increasing understanding of dynamics of not only breast motion, but other auxiliary structures, not controlled centrally, although involved in whole body motions.