Biomechanical loads in running-based sports: estimating ground reaction forces from segmental accelerations

Training loads are monitored in sports as part of a process which aims to enhance performance whilst simultaneously reducing the risk of injury. Although physiological loads have been investigated extensively, biomechanical loading is still poorly quantified and, therefore, largely unexplored. Ground reaction force (GRF) is a well-established measure of external whole-body biomechanical loading, which drives and contributes to the internal stresses on e.g. muscles, tendons and bones. GRF might thus be used to further understand the relationship between whole-body biomechanical loads and performance and injuries, but valid methods for accurately estimating GRF outside laboratory settings are currently unavailable. However, since GRF is determined by the accelerations of the body’s different segments, currently popular body-worn accelerometers might allow for estimating GRF in the field. Therefore, the aim of this thesis was to investigate if GRF can be estimated from segmental accelerations, especially for dynamic and high-intensity running tasks that are frequently performed during running-based sports. The first two studies showed that a two mass-spring-damper model can be used to accurately reproduce overall GRF profiles and impulses for various high-intensity running tasks, but that this model cannot be used to predict GRF from trunk accelerometry. These results suggest that trunk accelerations alone are insufficient to accurately predict GRF in this manner, but additional information about accelerations of other segments allows for alternative approaches to be explored. Therefore, the third study aimed to estimate GRF from multiple segmental accelerations using a direct mechanical approach. GRF profiles from full-body segmental accelerations were estimated reasonably across dynamic and high-intensity running tasks, but errors substantially increased when the number of segments was reduced. Since these results further support the suggestion that one or several segmental accelerations are unlikely sufficient to estimate whole GRF waveforms, the fourth study aimed to identify key segmental contributions to distinct GRF features using principal component analysis. However, this study showed that dominant segmental acceleration characteristics and associated GRF features, as well as the relative importance of these features, are highly complex and task-specific. Together these findings show that it is unlikely that one or several segmental accelerations can provide accurate and meaningful estimates of GRF across different running activities. These outcomes warrant caution when using body-worn accelerometers to estimate GRF and monitor whole-body biomechanical loads during running-based sports in the field.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

Liverpool John Moores University

Year dc:date.issued

2019

Author dc:creator

• Verheul, J

Contributors dc:contributor

• Robinson, M
• Lisboa, P
• Gregson, W

• RC1200 Sports Medicine

DOI dc:identifier.doi

https://doi.org/10.24377/LJMU.t.00010232

OAI identifier oai:identifier

oai:researchonline.ljmu.ac.uk:10232