Summary

The purpose of this study is to determine the relationship between force plate and FMS scores as well as signs of radiographic femoroacetabular impingment (FAI) on ski jumping performance.

Abstract

Introduction

Nordic combined (NC) and ski jumping (SJ) athletes are at higher risk for femoroacetabular impingement (FAI) compared with age-matched peers in the general population. Force plate testing and/or Functional Movement Screening (FMSTM) are among several known instruments utilized to monitor, prevent, and predict associated injury. The purpose of this study is to determine the relationship between force plate and FMS scores as well as signs of radiographic FAI on ski jumping performance.

Methods

Elite NC and jumpers who compete at the national and international level were prospectively recruited at the time of preseason testing. Athletes with any injuries at the time of testing that prevented them from training, competition, or performance testing were excluded. FMS testing was performed by two certified exercise physiologists (EP) to assess muscular imbalance, instability, and immobility. Vertical jump, balance, and plank testing was performed on all healthy athletes using commercially available force plate technology. The primary outcomes were ski jump distance and ski jump score measured for each athlete on a single jump. Ski jump scoring was assessed in accordance with International Ski Federation (FIS) official scoring guidelines.

Results

A total of 21 athletes with available competition scores were included in the study. On FMS testing, most subjects in both groups SJ (6 athletes, 67%) and NC (8 athletes, 73%) were positive for core instability. There were slightly higher rates of hip instability and ankle stiffness in the SJ cohort compared to the NC cohort, although not statistically significant (p>0.05). Ski jump distance score was significantly positively correlated with force plate vertical jump height, max acceleration, max velocity, concentric impulse, countermovement depth and jump height flight time, (p<0.05). FMS testing results and radiographic presence of FAI were not associated with ski jumping performance.

Discussion And Conclusion

The present study is the first to our knowledge to demonstrate that significant positive correlations exist between competition scores and max jump height, acceleration, max velocity, counter depth movement, and concentric impulse as measured on maximal counter-movement jump (CMJ) force plate testing in elite NC and SJ athletes. Our findings suggest that athletes competing in ski jumping may benefit from training that emphasizes the stretch-shortening cycle and the transition from eccentric exercise to concentric contraction, which have the potential to optimize performance and promote joint stability. The use of force plate technology to track counterdepth movement and resulting concentric contraction force may assist in guiding athlete training and goal-setting.