High plantar pressure has been associated with increased risk of injury. The characteristics of each physical activity determine the load on the lower limbs. The influence of Nordic Walking (NW) technique on plantar pressure is still unknown. The aim of this study was to analyze the differences between plantar pressure during NW with the Diagonal technique (DT) versus Alpha technique (AT) and compare them with the pressure obtained during normal walking (W). The normality and sphericity of the plantar pressure data were checked before performing a two-way repeated measures ANOVA in order to find differences between speeds (preferred, fast) and the gait (NW, W) as within-subject factors. Then, a t-test for independent measures was used to identify the specific differences between NW techniques. The strength of the differences was calculated by means of the effect size (ES). The results demonstrated that during NW with AT at preferred speed the pressure was lower under the Calcaneus, Lateral Metatarsal and Toes compared to the DT group (p = 0.046, ES = 1.49; p = 0.015, ES = 1.44; p = 0.040, ES = 1.20, respectively). No differences were found at the fast speed (p > 0.05). Besides the increase in walking speed during NW (p < 0.01), both technique groups showed lower pressure during NW compared to W under the Hallux and Central Metatarsal heads (F = 58.321, p = 0.000, ES = 2.449; F = 41.917, p = 0.012, ES = 1.365, respectively). As a practical conclusion, the AT technique may be the most effective of the NW techniques at reducing plantar pressure while allowing NW practitioners to achieve the physiological benefits of NW.
Keywords: biomechanics; foot; loading; poles.