The University of Ottawa foot pressure studies, that used elite ski instructors, noted that the averaged maximal pressures were relatively similar for all types of turns ranging from 28 to 38 N/cm 2 (Table 2). The maximum pressures obtained during all types of turns reached up to 45 N/cm2 for one of the subjects while performing Short Radius turns. Of interest to the researchers was the apparent trend for peak forces to be higher under the left foot in three out of the four types of turns. While the researchers offered no explanation for this variance they noted:
“A factor that was not controlled during data collection was the equipment worn by the subjects. The skiers wore different boots, and used different skis, although two of them had the same brand and model of skis and boots. It still has yet to be determined if that factor had any effect on the results. A point that all the skis that the subjects used had in common is that the skis were all sharp side-cut skis (also called shaped skis). Another equipment variation which may have affected in-boot measurements, is that some subjects (n=5) wore custom designed footbeds, while the other did not.”
I was involved with foot pressure studies in 2001 using the same Novel Pedar system as the University of Ottawa researchers. In looking at their data, it appears as if the Novel Pedar system my team used had more sophisticated software.
The image below shows a screen image of Pedar data file from the skier in the right hand frame.
(click on the image to enlarge)
As with the University of Ottawa studies, the Pedar pressure data was synced to video of the skier.
The lines radiating from the heel to the ball of the foot are what are called ‘excursions’ of center of pressure or COP. The red lines are the excursions from the heel to the head of the first metatarsal. The blue lines are excursions from the forefoot to the hindfoot. The red dot is the COP under the head of the first metatarsal. The blue dot is COP under the heel.
Note the dramatic differences in the pressure patterns between the left and right feet; the same pattern seen by University of Ottawa researchers. The pressure pattern, especially the excursions, is much tighter under the left foot than the right foot while the pressures on the right foot are literally ‘all over the pressure map’.
- Note the position of the red dot representing COP in the left foot. COP is over the inside edge whereas it is more towards the outboard side of the turn in the right foot and less localized.
- The pressures under the heel of the right foot are much higher than the pressures under the heel of the left foot; 6 N/cm2 vs 10 N/cm2, not good.
- Note also that the excursions of COP radiate to the 1st, 2nd and 4th toes in the right foot whereas COP never exceeds the limits of the head of the first metatarsal in the left foot.
It should be obvious on which side the turns are better. The preceding data is an example of some of the best data captured from an elite skier. The skier is a former World Cup champion. The pressure pattern of the right foot indicates significant functional issues.
A starting point would be a comprehensive functional assessment of the skier.