KINEMATICS OF RECOVERY FROM A STUMBLE

Background. Injuries most frequently related to accidents in elderly p ersons are falls during locomotion and stair ascent and descent. Altho ugh numerous risk factors have been related to falling behavior, effec tive strategies to predict and prevent falls have not evolved. The rat ionale underlying this study was that systematic experimental and anal ytical investigation of the effects of perturbations during locomotion and the subsequent requisites for recovery could lead to the developm ent of clinically relevant evaluation(s) capable of identifying a pred isposition to falling. The present study is the first biomechanical in vestigation Of recovery from an anteriorly directed stumble. Methods. Seven healthy, young males participated in this study. While the subje cts walked along a walkway in the laboratory, stumbles were unexpected ly induced using a mechanical obstacle. Videotape records of these tri als were analyzed and selected sagittal plane kinematics extracted. Re sults. The perturbation caused an increase in the maximum trunk flexio n angle from 4.3 degrees (control) to 18.3 degrees (p = .057), and thi s change was significantly associated with preperturbation walking vel ocity (p = .036). The maximum hip and knee flexion angles increased fr om 26 to 47 degrees (p = .039) and from 60 to 89 degrees (p = .009), r espectively. The increases in maximum hip flexion velocity (79%) and m aximum knee extension velocity (36%) were not significant. Conclusions . Identification of the principal elements of control during perturbed locomotion can contribute to understanding the relationship between s pecific age-related performance deficits and some types of falling beh avior. The results suggest that recovery from a stumble is dependent u pon lower extremity muscular power and the ability to restore control of the flexing trunk.