Limitations of Foot-Worn Sensors for Assessing Running Power

Abstract

Running power as measured by foot-worn sensors is considered to be associated with the metabolic cost of running. In this study, we show that running economy needs to be taken into account when deriving metabolic cost from accelerometer data. We administered an experiment in which 32 experienced participants (age = 28 ± 7 years, weekly running distance = 51 ± 24 km) ran at a constant speed with modified spatiotemporal gait characteristics (stride length, ground contact time, use of arms). We recorded both their metabolic costs of transportation, as well as running power, as measured by a Stryd sensor. Purposely varying the running style impacts the running economy and leads to significant differences in the metabolic cost of running (p < 0.01). At the same time, the expected rise in running power does not follow this change, and there is a significant difference in the relation between metabolic cost and power (p < 0.001). These results stand in contrast to the previously reported link between metabolic and mechanical running characteristics estimated by foot-worn sensors. This casts doubt on the feasibility of measuring running power in the field, as well as using it as a training signal.

Revealing the Mutual Information between Body-Worn Sensors and Metabolic Cost in Running

“…Therefore, using these devices to organize long-term training may not have the intended effects, as changes in RE can lead to arbitrary changes in displayed power. In this work, we showcase unpublished data that was recorded simultaneously with the previous work by Baumgartner et al [ 11 ].…”

“…Previous work has shown that there is not necessarily a strict correlation between and running power as measured by a single acceleration sensor at the foot [ 11 ]. We illustrate this same observation in Figure 4 , in which we show correlation plots between the consumed oxygen and the average magnitude of acceleration of a single foot-worn sensor.…”

“…As such, it is important for long-term training success to consider changes in the running economy [ 10 ]. It has recently been shown that foot-worn sensors are limited when it comes to adaptation to changing the running economies [ 11 ].…”

“…Our work is based on a study by Baumgartner et al [ 11 ]. In their study, the authors aimed to determine the validity of foot-worn sensors for measuring running power.…”

Detection of Ground Contact Times with Inertial Sensors in Elite 100-m Sprints under Competitive Field Conditions

“…To substitute these time intensive and costly systems, the integration of IMUs for diagnostics in gait [15][16][17], runs [18][19][20], or sprinting [13,[21][22][23][24][25] received much attention in the last decade. Various studies introduced new or adapted sprint performance metrics based on data of IMUs.…”