Force Measurement System for Roller-Ski Skating

Abstract

For a detailed biomechanical analysis of roller-ski skating a precise measurement of ground reaction forces is needed in addition to the measurement of the kinematic parameters. An innovative portable force measuring system was developed from processed roller-skis and ski poles equipped with strain gauges. The measuring system can measure normal (with respect to the upper surface of the roller-ski) and transverse forces (in the axial direction of the wheel) on each wheel, and axial forces in the ski poles. Force sensors are connected by cables to the data acquisition system carried in a backpack by the runner. In case of terrain usage, also a portable computer and a power supply are carried in the backpack. Calibration procedure for this measurement system is presented and measurement uncertainty of the sensors is calculated. The estimated measurement uncertainty of the entire measuring chain of individual roller-ski sensor, at a confidence level of 95 %, is up to ± 2,34 % of the maximum calibration forces. For the sensors of the poles this value makes up to ± 1,47 % of the maximum calibration force. Sample data from a roller-ski skating trial on a treadmill is presented and interpreted.

Keywords

• cross-country skiing
• force measurement system
• kinetics
• treadmill roller-skiing