Introduction: Falling leads all causes of older adult (>60 years) injuries. Most community-dwelling older adult falls occur in the forward direction with initial ground contact resulting on the hands. Importantly, older adult sex-based comparisons on fall arrest biomechanics are lacking. This work investigated possible forward fall arrest capacity (FAC) differences between older males and older females, where FAC was defined as the ability to experience a fall without consequential injury (e.g., high submaximal ground forces, high energy absorption).
Methods: Participants conducted controlled forward descents (CFDs), a movement similar to the downward phase of a push-up, and quick release (QR) forward fall landing simulations using a novel rig apparatus. Three trials were recorded for each condition at 30° body lean from vertical. Biomechanical measures included range of motion, maximum joint moments, maximum ground forces, and overall energy absorption. On the same day, participants performed maximal isometric (ISO) strength testing including shoulder abduction, shoulder flexion, elbow extension, handgrip, and the push-off test. Participants then conducted maximal concentric and eccentric arm extensions using an isokinetic dynamometer. Three trials were averaged for each arm in each test.
Results: Seventy-four participants were recruited. CFD analysis included 38 females (agemales: 73.1±8.0 years, agefemales: 69.2±6.3). Four participants (two female) did not complete QR testing due to safety concerns. Age was significant between sexes (p=0.023) while body mass index (BMI) was similar (p=0.114). Males were noticeably stronger than females in every strength test (all p<0.001) and displayed stronger upper extremity joint moments (p<0.05) during CFDs and QRs. There was no CFD sex difference in maximum contact force or energy absorption (p>0.05), but the opposite was found in QR testing (p<0.05). Multiple relationships between our strength variables and biomechanical outcomes were indicated. BMI served as a uniquely important descriptive predictor for certain biomechanical measures. While some regression models were strong, much variance remains unexplained (range radj2=0.127-0.336).
Conclusions: Based on our protocol involving CFDs and QRs, older males may have a better FAC than older females, who applied smaller loads on the hands and absorbed less overall energy in QR testing; however, no clear theme emerged within the strength and biomechanics relationships.