Asymmetries in the Technique and Ground Reaction Forces of Elite Alpine Skiers Influence Their Slalom Performance
Abstract
:1. Introduction
2. Materials and Methods
2.1. Participants
2.2. Experimental Setup
2.3. Computation
2.4. Statistical Analyses
3. Results
3.1. Descriptive Statistics, Symmetry and Jaccard Indices (SI and JI)
3.2. Multivariable Regression Models
4. Discussion
5. Conclusions
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
References
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Variable | Left Turn | Right Turn | p-Value | SI [%] | JI [%] |
---|---|---|---|---|---|
Shank angle [ °] | |||||
Outside leg | 30.8 ± 4.5 | 29.4 ± 4.6 | 0.49 | 93.8 ± 5.4 | 52.2 ± 19.5 |
Inside leg | 33.2 ± 3.8 | 34.2 ± 2.4 | 0.84 | 92.8 ± 4.0 | 41.5 ± 16.2 |
Knee flexion [ °] | |||||
Outside leg | 46.99 ± 8.9 | 52.20 ± 7.2 | 0.11 | 92.5 ± 4.4 | 28.7 ± 24.3 |
Inside leg | 85.73 ± 9.3 | 81.25 ± 9.9 | 0.34 | 96.1 ± 2.2 | 39.1 ± 21.7 |
Hip flexion [ °] | |||||
Outside leg | 37.4 ± 3.3 | 28.02 ± 3.0 | 0.70 | 95.71 ± 2.2 | 53.35 ± 14.9 |
Inside leg | 71.8 ± 4.4 | 68.79 ± 5.5 | 0.22 | 97.52 ± 1.7 | 50.64 ± 15.5 |
GRF (pressure insoles) [% BW] On the entire foot | |||||
Outside leg | 126.2 ± 19.2 | 113.6 ± 21.6 | 0.21 | 92.9 ± 4.7 | 56.1 ± 18.9 |
Inside leg | 66.8 ± 7.4 | 76.0 ± 10.0 | 0.04 | 91.4 ± 5.7 | 56.0 ± 19.6 |
On the fore foot [% BW] | |||||
Outside leg | 62.5 ± 20.6 | 58.7 ± 26.85 | 0.75 | 88.4 ± 8.4 | 47.2 ± 21.6 |
Inside leg | 27.4 ± 9.2 | 37.8 ± 17.6 | 0.14 | 85.1 ± 10.1 | 42.7 ± 23.2 |
On the rear foot [% BW] | |||||
Outside leg | 63.8 ± 7.7 | 54.9 ± 16.6 | 0.17 | 87.8 ± 7.3 | 51.6 ± 14.4 |
Inside leg | 39.4 ± 9.13 | 38.6 ± 15.8 | 0.85 | 85.8 ± 15.2 | 52.9 ± 23.2 |
GRF * | |||||
Overall [% BW] | 287.5 ± 26.3 | 283.7 ± 17.5 | 0.72 | 98.2 ± 1.1 | 71.3 ± 2.7 |
Dependent Variable | Left Turn | Right Turn | p-Value | SI [%] | JI [%] |
---|---|---|---|---|---|
Time | |||||
Turning time [s] | 0.87 ± 0.03 | 0.87 ± 0.03 | 0.68 | 97.5 ± 1.7 | n/a |
Trajectory | |||||
Turning length [m] | 12.61 ± 0.30 | 12.51 ± 0.39 | 0.59 | 97.9 ± 1.5 | n/a |
Turningradius[m] | 9.34 ± 0.44 | 9.32 ± 0.52 | 0.95 | 97.6 ± 1.5 | 56.1 ± 18.9 |
Velocity | |||||
Average velocity [m/s] | 14.5 ± 0.42 | 14.5 ± 0.37 | 0.97 | 99.6 ± 0.00 | n/a |
Energy associated with | |||||
Instantaneous performance [J/kg/m] | −10.69 ± 4.67 | −10.51 ± 2.98 | 0.92 | 70.6 ± 23.0 | 47.3 ± 14.1 |
Sectional performance [Js/kg/m] | −1.90 ± 0.39 | −1.87 ± 0.50 | 0.91 | 84.2 ± 13.7 | n/a |
Dependent Variables → Independent Variables ↓ | SI for Turning Time | SI for Turning Length | JI for Turning n Radius | SI for Turning Radius | SI for Average Velocity | SI for Instantaneous Performance | SI for Sectional Performance |
---|---|---|---|---|---|---|---|
Shank angle | |||||||
JI for outside leg | - | - | 0.33 **,#4 | - | - | - | - |
SI for outside leg | - | - | - | - | - | 3.97 ***,#10 | 3.01 **,#13 |
JI for inside leg | 0.08 *,#1 | 0.07 **,#2 | - | - | - | - | - |
SI for inside leg | - | - | - | - | - | 5.77 **,#11, 7.16 **,#12 | - |
Hip flexion | |||||||
JI for outside leg | - | - | - | −0.10 *,#5 | 0.01 *,#6 | - | - |
SI for outside leg | - | - | - | - | 0.09 *,#7 | 8.33 *,#12 | - |
GRF on entire foot a | |||||||
JI for GRF outside leg | - | - | 0.25 *,#4 | - | - | - | - |
SI for GRF outside leg | - | - | - | 0.46 **,#5 | - | - | - |
SI for GRF inside leg | 0.14 *,#1 | 0.13 **,#2, 0.11 *,#3 | - | - | - | - | - |
JI for GRF inside leg | - | - | - | - | - | - | 0.56 *,#13 |
GRF on rear foot a | |||||||
JI for outside leg | - | - | - | - | −0.02 **,#8 | −1.03 **,#11 | - |
SI for GRF outside leg | - | - | - | - | −0.03 **,#9 | - | - |
Overall GRF b | |||||||
JI | - | 0.16 *,#3 | - | - | - | - | - |
SI | - | - | - | - | 0.10 *,#6, 0.12 **,#7, 0.15 **,#8, 0.16 **,#9 | - | - |
R2 | 0.72 *,#1 | 0.80 **,#2, 0.75 *,#3 | 0.80 **,#4 | 0.74 *,#5 | 0.73 *,#6, 0.81 **,#7, 0.84 **,#8, 0.83 **,#9 | 0.86 ***,#10, 0.82 **,#11, 0.84 **,#12 | 0.76 **,#13 |
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Supej, M.; Ogrin, J.; Šarabon, N.; Holmberg, H.-C. Asymmetries in the Technique and Ground Reaction Forces of Elite Alpine Skiers Influence Their Slalom Performance. Appl. Sci. 2020, 10, 7288. https://doi.org/10.3390/app10207288
Supej M, Ogrin J, Šarabon N, Holmberg H-C. Asymmetries in the Technique and Ground Reaction Forces of Elite Alpine Skiers Influence Their Slalom Performance. Applied Sciences. 2020; 10(20):7288. https://doi.org/10.3390/app10207288
Chicago/Turabian StyleSupej, Matej, Jan Ogrin, Nejc Šarabon, and Hans-Christer Holmberg. 2020. "Asymmetries in the Technique and Ground Reaction Forces of Elite Alpine Skiers Influence Their Slalom Performance" Applied Sciences 10, no. 20: 7288. https://doi.org/10.3390/app10207288
APA StyleSupej, M., Ogrin, J., Šarabon, N., & Holmberg, H.-C. (2020). Asymmetries in the Technique and Ground Reaction Forces of Elite Alpine Skiers Influence Their Slalom Performance. Applied Sciences, 10(20), 7288. https://doi.org/10.3390/app10207288