Age and gender differences in peak lower extremity joint torques and ranges of motion used during single-step balance recovery from a forward fall

Previous studies have found substantial age and gender group differences in the ability of healthy adults to regain balance with a single step after a Forward fall. It was hypothesized that differences in lower extremity join t strengths and ranges of motion (ROM) may have contributed to these observ ed differences. Kinematic and forceplate data were therefore used with a ri gid-link biomechanical model simulating stepped leg dynamics to examine the joint torques and ROM used by subjects during successful single-step balan ce recoveries after release from a Forward lean. The peak ROM and torques u sed by subjects in the study were compared to published estimates or measur ed values of the available maxima. No significant age or gender group diffe rences were found in the mean ROM used by the subjects for any given initia l lean angle. As initial lean angle increased, larger knee ROM and signific antly larger hip ROM were used in the successful recoveries. There were sub stantial gender differences and some age group differences in peak lower ex tremity joint torques used in successful recoveries. Both young and older f emales often used nearly maximal joint torques to recover balance. Subjects ' maximum joint strengths in plantarflexion and hip flexion were not good p redictors of single-step balance recovery ability, particularly among the f emale subjects. (C) 2000 Elsevier Science Ltd. All rights reserved.