In vivo analysis of hip joint loading on Nordic walking novices.

Objective: To evaluate the influence of Nordic walking (NW) on hip joint loads in order to determine whether it can be safely performed during postoperative physiotherapy in patients after orthopeadic surgery of the hip.

Methods: Internal hip joint loads were directly measured in vivo in 6 patients using instrumented hip prostheses during NW and ordinary walking (OW). All patients received training in two different NW techniques (double-poling and the diagonal technique) by a certified NW instructor. Measurements were conducted on a treadmill at a speed of 4 km/h on level ground, at 10% inclination and at 10% slope as well as on a level lawn at a self chosen comfortable speed. Resultant contact force (F), bending moment (M) and torsional torque (M) were compared between NW and OW as well as between both NW techniques.

Results: Joint loads showed a double peak pattern during all setups. Neither NW technique significantly influenced hip joint loads at the time of the first load peak during contralateral toe-off (CTO), which was also the absolute load peak, in comparison to OW. Compared to OW, double-poling significantly reduced F and M at the time of the second load peak during the contralateral heel strike (CHS) on level ground both on the treadmill (- 6% and - 7%, respectively) and on the lawn (- 7% and - 9%). At 10% inclination, the diagonal technique increased F and M at CHS (by + 6% and + 7%), but did not increase the absolute load peak at CTO.

Conclusion: Joint loads during NW are comparable to those of OW. Therefore, NW can be considered a low-impact activity and seems to be safe for patients that are allowed full weight bearing, e.g. during postoperative rehabilitation after THA.