Monitoring the Performance of Alpine Skiers with Inertial Motion Units: Practical and Methodological Considerations

Abstract

Although reliable feedback is crucial to improving the performance of competitive alpine skiers, the coach's eye may not be sensitive enough to detect small, but highly significant “mistakes”. Monitoring of the performance of alpine ski racers by inertial motion units (IMU) has proven to be of value in this context and here we summarize practical and methodological aspects of this approach. Methodologically, the IMUs employed should combine high sampling frequencies with minimal signal drift. The sensors should be positioned to sense the movement of the bones in a given body segment while being protected as much as possible against impact with the ski gates. The data obtained, often synchronized with input from Global Satellite Navigation Systems (GNSS), are usually refined utilizing advanced biomechanical models and other computerized approaches. In practice, the combination of inertial sensors and GNSS allows accurate monitoring of skiing kinematics (technique) and the movement of the skier’s center-of-mass, also allowing analysis of both whole-body vibrations (WBV) and loss of mechanical energy. Presentation of the findings to coaches and athletes can be facilitated by synchronizing them with video recordings. Recent advances in IMU technology, including miniaturization, wireless communication, direct storage of data in the cloud, and processing with artificial intelligence may allow these sensors, in-combination with GNSS, to become real-time virtual alpine ski coaches, perhaps the next step in the development of this sport.

Influence of the Slope and Gate Offset on Movement Variability and Performance in Slalom Skiing

“…In alpine skiing, IMUs can offer a number of advantages that go beyond the limitations of traditional or laboratory methods [43][44][45][46][47][48][49]: compact and lightweight, easily portable and positionable, capable of wireless operation, and with the ability to capture a substantial amount of data (i.e., several runs), instantaneous data acquisition, and the optimization of data collection due to automatic synchronization among all the built-in sensors. However, to the best of our knowledge, no research has been conducted yet to evaluate MV through IMUs in the domain of alpine skiing, nor has it been evaluated regarding how the characteristics of the terrain (flatter vs. steeper slopes) and course setting (gate offset: i.e., turned vs. straighter courses) influence skier MV.…”

Simplification of calibration of low-cost MARG sensors without high-precision laboratory equipment

“…Afterword, MARG sensors were introduced in controlling Unmanned Aerial Vehicle (UAV) and capturing its motion through providing precise attitude information to the control system [8]. In sports, attitude information can be utilized for instance in estimating the performance and the characteristics of skiers [9]. In addition, MARG sensors can be used in measuring countermovement jump performance metrics in elite basketballers [10].…”

Addressing the unresolved challenge of quantifying skiing exposure—A proof of concept using smartphone sensors

“…Specifically, in alpine skiing, inertial measurement units (IMUs), global positioning systems (GPSs), pressure-sensitive insoles, and surface electromyography (sEMG) have been applied to analyse skiers' kinematics, kinetics, and muscle activation patterns ( 5 – 23 ). An overview of their application and the resulting methodological consequences for further use has recently been addressed in two review articles ( 24 , 25 ). Furthermore, it has been suggested that sensor-based approaches may provide feedback to enhance sports performance or prevent injury in general, not just for competitive athletes ( 26 ).…”