Force plate testing is correlated with jumping performance in elite Nordic skiers

Abstract

Introduction

Ski jumping (SJ) and Nordic combined (NC) athletes are at higher risk for femoroacetabular impingement (FAI) compared to the general population.

Objectives

The purpose of this study was to determine the relationship between force plate testing metrics, Functional Movement Screen (FMS) scores, and radiographic signs of FAI and SJ performance.

Methods

Elite SJ and NC athletes were prospectively recruited. FMS testing was performed to assess muscular imbalance, instability, and immobility. Vertical jump testing was performed using a commercially available force plate device. Ski jump score and distance score were measured on a single jump for each athlete.

Results

Twenty-one athletes (10 SJ, 11 NC) with competition scores were included. On FMS testing, most SJ (67%) and NC (73%) athletes demonstrated core instability. There were higher rates of hip instability and ankle stiffness among SJ athletes, although not statistically significant (P > .05). Ski jump distance score was significantly positively correlated with force plate vertical jump height, maximum acceleration, maximum velocity, concentric impulse, counter-movement depth, and flight time (P < .05). FMS testing results and radiographic FAI were not significantly associated with competition scores.

Conclusions

Our results show significant positive correlations between competition scores and force plate jump testing performance as measured by jump height, acceleration, maximum velocity, counter-movement depth, and concentric impulse in elite SJ and NC athletes. Our findings suggest that ski jumpers may benefit from training that emphasizes stretch-shortening cycles and eccentric-to-concentric contraction transition, which may optimize their performance and promote joint stability.