Kinematic and Kinetic Characteristics of Treadmill Roller Skis and Validation of Force Measurement Roller Skis
Effective skiing biomechanics is one of the most important elements that could enhance skiing performance. Understanding how speed and incline influence skiing biomechanics may help skiers, coaches, and instructors improve the skiing techniques.
“We found that the cycle characteristics of the V2 skating technique were affected by the treadmill incline and speed. The relative contribution of pole forces versus ski forces in overcoming the total resistance did not change with incline change. However, when the speed was changing, the poles contributed more propulsive force and were more effective than skis in the skiing direction, and the contribution of legs slightly increased with the increasing speed.” Zhao reflects.
Several instruments could be used to measure ground reaction forces from skis, but there remains a need for a valid, and user-friendly system that can simultaneously measure multiple force components.
“Although there are several instruments which could be used to measure the forces from skis, they all have their disadvantages. For example, although the force measurement systems which buried in the snow had no influence on the skiing technique, the movement was restricted to a small area. The pressure insoles were found to barely influence the skier’s performance, but the pressure measurement only provided forces in one unknown direction and could be unreliable as the insoles may not detect all the forces transmitted between the foot and footwear.” Zhao says.
“Force measurement ski bindings were design and validated by Olli Ohtonen et al. from our unit before. This binding could be used on roller skis and on normal skis. But the increased weight and height of these bindings may affect the skier’s performance. Therefore, the 2D force measurement roller ski was designed.” Zhao says.
“We are happy that the newly designed 2D force measurement roller ski, which was constructed in co-operation with VTT, was found to be valid. I’m also looking forward using this force measurement device in future cross-country skiing studies.” Zhao says.
The dissertation consisted of four sub-studies involving a total of 14 experienced skiers familiar with treadmill roller skiing. The China Scholarship Council and the Ģֱ supported this work.
Shuang Zhao graduated with a Bachelor in education from Chengdu Sports University (in China) in 2015 and as a Master of Education from the Beijing Sports University (in China) in 2018. Shuang Zhao has worked as a doctoral researcher for the Faculty of Sport and Health Sciences in Vuokatti at the Ģֱ since January of 2019.
Additional information:
Shuang Zhao
shuang.s.zhao@jyu.fi
