Footstrike kinematic effects of motor learning strategies to retrain running gait

Abstract

Running gait retraining, which uses motor learning strategies, is increasingly being advocated as an effective rehabilitation approach to allow runners to mitigate the risks of re-injury and to remain physically active (Davis and Crowell, 2011, Clinical Biomechanics, 26, 78-83). By providing gait retraining cues, lower-limb running kinematics at footstrike may be altered to affect the mechanical risks of overuse running injuries. The aim of this study was to develop insight into the influence of a short-term gait retraining strategy on the footstrike kinematics of rearfoot-striking runners. With institutional ethical approval, lower-limb kinematics were tracked using CODAmotion V6.79.3 (Charnwood Dynamics Ltd, Leicestershire, UK) analysis during treadmill running conditions for six recreational, habitually rearfoot-striking runners (mean ± SD age: 24.8 ± 6.2 years; height 1.69 ± 0.08 m; body mass 67.9 ± 7.1 kg). Each participant completed three, six minute running conditions (10 kilometres per hour) separated by a five minute rest period. A normal (N) condition and two intervention conditions using the verbal cues of “run like you are trying to squash oranges” (O) and “run quietly” (Q) were completed in a randomised order. Sagittal and frontal plane kinematics were derived during the last minute of each six minute running condition. Footstrike was defined using the vertical acceleration data of the first contacting foot marker. While step frequency was maintained (mean ± SD all footstrikes: 1.40 ± 0.11 Hz, n = 159) across conditions, the O condition elicited a shallower foot orientation (difference: N = 7.6°, effect size [ES] = 0.66; Q = 6.0°, ES = 0.51) compared to the other conditions. While cueing had a small effect on the foot inversion-eversion angle (difference: O to N = 1.3°, ES = 0.23; O to Q = 1.0°, ES = 0.18), moderate effects on the rearfoot orientation were evidenced (difference: O to N = 3.2°, ES = 0.61; O to Q = 2.9°, ES = 0.50). More proximally, the two cueing conditions had large effects on the knee extension at footstrike compared to the N condition (O to N ES = 0.82; Q to N ES = 0.82). Conditional responses indicated the potential to elicit mechanical transitions in habitually rearfoot-striking runners using an analogy learning strategy. Short-term gait retraining strategies may accordingly be implemented in rehabilitation programmes to alleviate the kinematic risk of overuse running injury. Consideration of the associated physiological effects of the respective retraining programme are however, advocated.