The effect of stride length on lower extremity joint kinetics at various gait speeds

Abstract

Robot-assisted training is a promising tool under development for improving walking function based on repetitive goal-oriented task practice. The challenges in developing the controllers for gait training devices that promote desired changes in gait is complicated by the limited understanding of the human response to robotic input. A possible method of controller formulation can be based on the principle of bio-inspiration, where a robot is controlled to apply the change in joint moment applied by human subjects when they achieve a gait feature of interest. However, it is currently unclear how lower extremity joint moments are modulated by even basic gait spatio-temporal parameters. In this study, we investigated how sagittal plane joint moments are affected by a factorial modulation of two important gait parameters: gait speed and stride length. We present the findings obtained from 20 healthy control subjects walking at various treadmill-imposed speeds and instructed to modulate stride length utilizing real-time visual feedback. Implementing a continuum analysis of inverse-dynamics derived joint moment profiles, we extracted the effects of gait speed and stride length on joint moment throughout the gait cycle. Moreover, we utilized a torque pulse approximation analysis to determine the timing and amplitude of torque pulses that approximate the difference in joint moment profiles between stride length conditions, at all gait speed conditions. Our results show that gait speed has a significant effect on the moment profiles in all joints considered, while stride length has more localized effects, with the main effect observed on the knee moment during stance, and smaller effects observed for the hip joint moment during swing and ankle moment during the loading response. Moreover, our study demonstrated that trailing limb angle, a parameter of interest in programs targeting propulsion at push-off, was significantly correlated with stride length. As such, our study has generated assistance strategies based on pulses of torque suitable for implementation via a wearable exoskeleton with the objective of modulating stride length, and other correlated variables such as trailing limb angle.

Strategies for increasing gait speed in patients with hip osteoarthritis: their clinical significance and effects on hip loading

“…In 4 type C individuals, whose stride length decreased during fast gait, little change (0.8% increase) in peak hip adduction moment was observed despite an increase in gait speed of 11.0%. Increases in peak joint moments with increasing gait speed are known to be due mainly to the increase in stride length [ 3 , 4 , 6 , 7 ]. In healthy individuals who used a cadence-increasing strategy, little change in hip moments was observed, except for parts of the hip flexion and adduction moments in transition from normal to fast gait [ 3 ].…”

Validity of Measurement for Trailing Limb Angle and Propulsion Force during Gait Using a Magnetic Inertial Measurement Unit

“…TLA is the main contributor to an increase in propulsion force following training [17] and is changed by gait training [18][19][20][21]. In addition, TLA correlates with lower limb kinetics and ability to walk long distance [15,22,23]. erefore, propulsion force and TLA would be meaningful indicators, representing the kinetics and kinematics of gait quality during gait rehabilitation.…”

Strategies for increasing gait speed in patients with hip osteoarthritis: their clinical significance and effects on hip loading

“…In 4 type C individuals, whose stride length decreased during fast gait, little change (0.8% increase) in peak hip adduction moment was observed despite an increase in gait speed of 11.0%. Increases in peak joint moments with increasing gait speed are known to be due mainly to the increase in stride length [3,4,6,7]. In healthy individuals who used a cadence-increasing strategy, little change in hip moments was observed, except for parts of the hip exion and adduction moments in transition from normal to fast gait [3].…”

“…Moreover, the loading on the lower limb joints can be increased as the gait speed increases [3 − 7]. Increasing stride length rather than cadence causes an increase in peak external joint moment on hip exion, hip adduction, hip internal rotation, knee exion, knee adduction, and ankle plantar exion [3,4,6,7]. Therefore, differences in the strategies (i.e., increased stride length, increased cadence, or both) used to change gait speed could alter the loading on the lower limb joints.…”