Association of Perceived Fatigue with Gait and Heart Rate during Half Marathon Running using Body Worn Sensors
PRIGENT, G., APTE, S., KREMSER, W., AMINIAN, K. (2020): Association of Perceived Fatigue with Gait and Heart Rate during Half Marathon Running using Body Worn Sensors In: Book of Abstracts of the 25th Annual Congress of the European College of Sport Science
Running technique is one of the crucial factors that explain the change in performance and economy in runners’ skills levels . Fatigue has been shown to introduce changes in running technique, like shifting the landing mechanics from front-foot to midfoot running , change in contact and aerial times . A decrease in heart rate variability (HRV) has also been observed during sport-induced fatigue . However, the influence of fatigue of the above-mentioned metrics have mainly been explored in laboratory or in field intermittently. The aim of this study was to assess, continuously during half-marathon, the influence of fatigue on running movement and heart rate.
19 recreational runners were equipped during the Lausanne and Geneva half-marathon with an IMU (Gait Up, CH) on each foot and a combined GPS-IMU-ECG sensor (ASI, CH) attached to a chest belt. A specially developed smartphone application recorded Rating of Fatigue (ROF) , every 10 minutes through verbal communication. Spatio-temporal gait parameters were extracted from the feet IMU data using a dedicated algorithm . Statistical and complexity metrics of HRV and gait parameters were calculated over 10-minutes window. Two nonlinear approaches were explored : 1) Poincare plot via short (SD1) and long-term (SD2) variability and 2) detrended fluctuation analysis via short-term fractal scaling exponent α.
Based on result observations, a ROF value equal to 6 (10 is “total fatigue & exhaustion”) was selected as onset of fatigue (OF), defined as “the inability to maintain the required or expected force” . The half-marathon participants typically showed an increased coefficient of variation for cadence and higher asymmetry index for contact time after OF. The ratio SD1/SD2 of HRV highly increased after departure, reaching maximum values at OF, mainly due to a decrease of SD2. The scaling exponent α, extracted from RR-interval time series, significantly decreased after 10 minutes of running (from 1.5 to 1), and reached minimum values (~0.5) at OF. The decrease of SD2 and α suggest a reduction in long-term oscillations in heart rate .
The main contribution of this study was the continuous measurements of gait biomechanics, heart rate and ROF during half-marathon. Perceived fatigue during endurance running seems to be associated with higher gait variability and lower variability of heart rate. The results of this work will be extended further via statistical testing.
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