The Effect of Nordic Walking on Knee-Ankle Coordination Patterns in the Sagittal Plane: A Vector Coding Analysis.

Abstract

Nordic walking, quasi-quadrupedal walking, provides biomechanical benefits to the lower extremities, such as joint load distribution and increased gait speed compared with normal walking. However, limited evidence exists regarding how the Nordic walking affects knee and ankle joint kinematic coordination. The purpose of this study was to investigate sagittal plane kinematics and coordination patterns of the knee and ankle joints during walking and Nordic walking. Twelve healthy subjects performed five consecutive strides of both conditions while capturing time-series joint kinematics with a smartphone-based motion capture system (OpenCap). Knee-ankle coupling angles were computed and categorized into in-/antiphase and proximal/distal dominance. A paired t test was used to analyze discrete variables, including joint range of motion and the number of coordination phases derived from vector coding. Statistical parametric mapping was used to analyze differences in time-series knee and ankle joint angles. Our results showed that the knee range of motion was significantly smaller in Nordic walking ( P = 0.040), with reduced knee flexion during the early stance phase ( P = 0.001) and push-off to swing phase ( P < 0.001). Ankle plantarflexion increased during early stance phase ( P = 0.001), while ankle dorsiflexion was smaller in mid-stance ( P = 0.002) but greater before push-off ( P = 0.047). Compared with normal walking, Nordic walking exhibited a greater number of antiphase ankle plantarflexion phases ( P = 0.012), and fewer antiphase knee flexion phases ( P = 0.005). These findings suggest that, in novice adults, the quasi-quadrupedal gait strategy of Nordic walking alters interjoint coordination strategies in a manner distinct from normal walking, particularly by increasing ankle plantarflexion-dominant and decreasing knee flexion-dominant coordination patterns. This study is the first to apply vector coding to Nordic walking, providing new biomechanical insights into its coordination characteristics and potential rehabilitation relevance in novice Nordic walkers.