Matej Supej1, Jan Ogrin2. 1. Faculty of Sport, University of Ljubljana, Gortanova 22, 1000 Ljubljana, Slovenia. Electronic address: matej.supej@fsp.uni-lj.si. 2. Faculty of Sport, University of Ljubljana, Gortanova 22, 1000 Ljubljana, Slovenia.
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 snow-plough 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 6Hz. 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.
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 snow-plough 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 6Hz. 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.
Authors: John D Ralston; Ashutosh Raina; Brian W Benson; Ryan M Peters; Joshua M Roper; Andreas B Ralston Journal: Med Devices (Auckl) Date: 2020-12-08
Authors: Matt R Cross; Clément Delhaye; Jean-Benoit Morin; Maximilien Bowen; Nicolas Coulmy; Frédérique Hintzy; Pierre Samozino Journal: PLoS One Date: 2021-01-14 Impact factor: 3.240