Transmissibility of whole-body vibrations and injury risk in alpine skiing

Abstract

Objectives: Whole body vibrations in alpine skiing are a potential cause for frequent overuse and acute injuries. Therefore, the aim of the study was to investigate the transmissibility of vibrations from the skis to lower back and head. Attention was addressed to distinguish shocks and transient vibrations from long-lasting vibrations. Design: Whole body vibrations were analysed in snowplough swinging, basic swinging, short swinging and carved turns performed by eight highly skilled skiers. Methods: Power spectrum densities (PSD), running root-mean-square accelerations (RMS) and transmissibilities were estimated and analysed from 7 accelerometers positioned on skis, pelvis and head. Results: In the measurements frequency range, vibrations were effectively transmitted from the skis to the pelvis and to the head, with the highest transmissibility occurring at frequencies below 6 Hz. The highest transmissibility was observed for short swinging. The running RMS was cyclically increasing and decreasing with turning and shocks. Also, transient vibrations exhibited similar PSDs with considerably higher densities compared to overall PSDs. Conclusions: All form of alpine skiing were associated with random, periodic and transient vibrations. Skiing involving skidding was associated with higher vibration levels, higher transmissibilities and more pronounced shocks and transient vibrations compared to carving turns. Frequent skiers should preferably use carving instead of skidding techniques to decrease the risk for low back pain and loss of control.

<p>Physiological Vibration Acceleration (Phybrata) Sensor Assessment of Multi-System Physiological Impairments and Sensory Reweighting Following Concussion</p>

“…18 In sports medicine, headmounted and body-worn accelerometers have been used to compare measured and simulated responses of the human body to external mechanical excitations such as simulated sub-concussive head impacts 19 and to investigate the transmissibility of vibrations from the skis to lower back and head in alpine skiing. 20 Localized vibration of the calf muscles has been used to study the effects of fatigue on human postural stability. 21,22 The incorporation of whole-body vibration into fitness and injury treatment programs has also received significant interest, 23,24 although evidence regarding the corresponding physiological changes and therapeutic benefits remains unclear.…”

“…ASD is the standard engineering analysis tool for quantifying random vibrations in many different complex physical systems, 9 including the human body. [10][11][12][15][16][17][18][19][20][21][22][23][24][25][26] In addition to revealing significant details related to sensory reweighting, time-resolved ASD analyses also address the fact that postural sway signals are non-stationary, by capturing the significant time varying spectral changes 100,142 that result from intermittent balance control processes that utilize multiple physiological system inputs and outputs. Ensemble-average ASD analyses have been utilized to identify statistically significant spectral features that can distinguish patients vs. control groups.…”

Lower Back Complaints in Adolescent Competitive Alpine Skiers: A Cross-Sectional Study

“…From a biomechanical perspective, the following factors may contribute to overloading of the lower back structures in alpine ski racing [14]: (a) repetitive and heavy mechanical loads, particularly when accompanied by insufficient recovery between the training sessions [15]; (b) unphysiological postures (i.e., frontal bending, lateral bending, and torsion), associated with high ground reaction forces (up to 2.89 times the body weight) [16]; and (c) excessive exposure to low-frequency whole-body vibrations [17][18][19][20]. Since all of these factors are typical characteristics of alpine skiing-specific sports exposure, studying the relations between training attributes and lower back complaints is of superior importance.…”

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

“…In addition to the information provided by standard camcorder-based systems, IMU technology enables monitoring of whole-body vibrations (WBV) and the transmission of WBV produced during skiing [10,15,40,53,62,63,66]. By selecting technology in accordance with the ISO 8041 International Standards [25], the WBV acting on the skier can be evaluated on the basis of general recommendations for the exposure of workers to such vibrations (International Standard, ISO 2631-1 [24]).…”

“…The major challenges associated with such usage include the necessity of capturing large amounts of complex data on snow (during multiple runs through several gates or over the entire course) in a manner that minimizes post-processing, thereby providing results within a short period of time (in fact, immediately, if possible). In the case of alpine skiing, inertial sensors were first used as a complement to GNSS technology [38] and thereafter to monitor whole-body kinematics [3,27,51] and, later, more specific aspects of performance [9,12,13,40,53,62,63]. With inertial sensors, many of the limitations described above can be overcome, but, like all approaches, these also have their limitations (discussed below in the section on methodological considerations).…”