What Are Kinematic and Kinetic Differences between Short and Parallel Turn in Alpine Skiing?

Abstract

There are numerous programs worldwide adapted for alpine ski beginners and they all share the same primary goal—inclusion of skiing beginners in alpine ski schools. The final elements of ski school taught in the parallel skiing technique are parallel turn and short turn. Synchronized analysis of kinetic and kinematic parameters of the parallel turn (PT) and short turn (ST) was conducted to determine the main biomechanical differences from a standpoint of foot pressure and lower limb angles. Both elements were performed by nine male ski instructors (age 33.4 ± 8.62, height 179.52 ± 5.98 cm, weight 78.6 ± 8.88 kg). Kinetic and kinematic analysis was conducted on 180 turns, 90 for each element. Differences in kinetic and kinematic parameters between parallel and short turns were tested by a paired t-test. The main findings of our study are determined differences in the ratio of pressure distribution on the inside and the outside foot and differences in kinematic parameters of the outside leg between elements. The mentioned analysis can provide an objective insight into the complexity of each element and provide guidelines for teaching process of those elements. This study determined the reasons for higher complexity of ST compared to PT based on the objective evaluation of biomechanical factors.

Technique-Dependent Relationship between Local Ski Bending Curvature, Roll Angle and Radial Force in Alpine Skiing

“…The force data collected in our study align with the results of previous research [14][15][16][17][18][19]38,39], indicating a substantial discrepancy in the measured force between the outer and inner skis, with the force on the outer ski being greater. Our measurements indicate a maximum RF of the outer ski of approximately 1.5 times the subject's body weight, a result closely corresponding with the findings of Cross et al (1.4 × body weight) [21].…”

Recreational Alpine Skiing An Introduction

“…Pressure distribution in the two feet of expert skiers is around 75% in the outside foot and 25% in the inside foot [53,57]. This shows that the outside foot is primarily responsible for the turning of the ski due to shifted skier's center of mass, while the inside foot helps with skier's stability.…”

“…Indeed, the GRF reaches 3000 N, 3.5 times the skier's average body weight for professional skiers participating in Olympic events. Larger GRF from minimal skidding and maximal carving would allow skiers to transition from PT to the short turns (ST) [53]. STs are chopped unfinished parallel turns performed in a narrower corridor with greater difficulty than PT.…”

“…Range of movement could also refer to knee flexion. When performing STs, skiers are found to be in a lower position with more flexed knees than when performing parallel turns [53]. Hence, recreational skiers should aim to move one's waist and flex ones' knee in a wider range while maintaining balance.…”

“…Consequently, all forces are directed to the forward instead of forward and sideward motion of the ski, achieving higher velocity under the same force. In fact, velocity is in a positive feedback loop with GRF, so GRF is highest in downhill, the event with the highest velocity [53]. Lastly, though path choice is a major contributing factor, skiers usually choose higher velocity over a shorter trajectory [63].…”