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A master's thesis from Aalborg University
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Validation of a novel subject-specific musculoskeletal strength-scaling workflow using submaximal dynamic strength tests

Term

4. semester

Publication year

2019

Submitted on

Pages

49

Abstract

Introduction: The present study aimed at creating and verifying a workflow to perform subject-specific strength-scaling of musculoskeletal models, and validating the strength-scaled models using isometric joint torque measurements. Methods: The participants consisted of 21 males and 7 females. A field strength assessment across 10 exercises was used to estimate the participants’ one-repetition-maximum (1RM). The 1RM measures were implemented in an optimization routine, calculating a set of strength factors capable of scaling all included muscles in the 10 different exercise-specific musculoskeletal models. Further, peak joint torques were investigated using dynamometer obtained isometric strength measurements for elbow flexion and extension, knee flexion and extension, and ankle plantar flexion. Results: The optimization based strength-scaled models showed an improvement of mean normalized root mean square error from 48.39 (+/- 22.99) % to 28.13 (+/- 15.47) % compared to the standard-scaled models. Discussion: The optimization routine was faster than previously used methods and showed a higher accuracy than the standard strength-scaling of musculoskeletal models. Issues in the simple muscle models wrapping around the knee and ankle joints made the comparison with the dynamometer data infeasible. The present study shows an improvement when applying the optimization routine for whole body musculoskeletal models, and other or more exercises could easily be implemented for scalability. However, utilizing simple musculoskeletal muscle models cannot readily be used to estimate and compare peak joint torque for near end range of motion angles.