Does Nordic Walking technique influence the ground reaction forces?

Background: Nordic Walking (NW) practice has increased during the last decade, generating great benefits related to the reduction of ground reaction forces (GRF). However, there is still limited evidence regarding how the NW technique could affect GRF.

Research Question: To analyze the effect of the speed and the differences in ground reaction forces (GRF) between NW with Diagonal technique (DT) versus Alpha technique (AT) and compare them with normal walking (W) METHODS: 29 male physically active sport science students were randomly assigned to one of the training groups: AT (n = 15) or DT (n = 14). After 5 technique familiarization sessions, participants performed 5 experimental trials on a walkway for both NW and W at two different walking speeds, previously randomized. A two-way repeated measures ANOVA analysis was carried out to find differences between speeds (preferred, fast) and gait (NW, W) as within-subject factors and NW techniques (DT vs AT) as between-subject factor.

Results: During NW, both technique groups (AT, DT) showed an increase in GRF variables compared to W, such as in stance time (2.9 % mean increment, p < 0.01, ES = 0.3; 95 %IC[-0.027, -0.008]), vertical force impact or vertical heel strike variables (4.9 % mean increment, p < 0.01, ES = 0.4; 95 %IC[0.101, 0.036]; 7.3 % mean increment, p < 0.01, ES = 0.8; 95 %IC[-0.133, -0.081] respectively). Moreover, AT group experienced significant lower forces at vertical force at midstance (10.1 % mean descent, p = 0.036, ES = 0.3; 95 %IC[-0.083, -0.009]) and higher forces at AP propulsive forces (23.7 % mean increment, p < 0.001, ES = 0.6; 95 %IC[0.078, 0.202) and ML max force (14.0 % mean increment, p = 0.045, ES = 0.3; 95 %IC[0.002, 0.026]) compared to DT group. Walking speed was significantly higher during NW (Preferred: 1.89 ± 0.18 m/s; Fast: 2.17 ± 0.21 m/s) compared to W (Preferred: 1.76 ± 0.15 m/s; Fast: 2.04 ± 0.19 m/s) in both speed conditions.

Significance: NW favours an increase in GRF and speed in comparison with Walking, independently of the technique, with no evidence that justifies the use of one technique or another.