Modelling the female torso and breast during physical activity: Implications on spinal loading

Area of Science:

• Biomechanics
• Musculoskeletal modeling
• Human motion analysis

Background:

• Current female torso models often overlook breast position and movement during physical activity.
• This oversight may lead to inaccuracies in simulating spinal loading.

Purpose of the Study:

• To compare the effects of three female torso models (integrated, fixed, and dynamic breast) on spinal joint moments.
• To determine the impact of breast motion on biomechanical simulations during running and jumping.

Main Methods:

• Developed and compared integrated, fixed, and dynamic breast models for female torso simulation.
• Analyzed differences in lumbar and thoracic spine joint moments during simulated running and jumping activities.

Main Results:

• Integrated and fixed breast models showed minimal differences in lumbar spine moments (<0.05 Nm/kg).
• The dynamic breast model revealed significant differences in lumbar spine moments (up to 0.86 Nm/kg during running, 0.89 Nm/kg during jumping).
• Similar patterns were observed for thoracic spine moments, with the dynamic model showing greater deviations.

Conclusions:

• Breast motion significantly influences spinal loading during running and jumping.
• Future female musculoskeletal models should incorporate breast mass and motion for accurate biomechanical analysis.
• Neglecting breast dynamics can misrepresent spinal loading in female-specific simulations.