Towards evidence based strength training: a comparison of muscle forces during deadlifts, goodmornings and split squats

Florian Schellenberg,William R Taylor,Silvio Lorenzetti

doi:10.1186/s13102-017-0077-x

Florian Schellenberg, William R Taylor + Show 1 more

Open Access

https://doi.org/10.1186/s13102-017-0077-x

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Abstract

BackgroundTo ensure an efficient and targeted adaptation with low injury risk during strength exercises, knowledge of the participant specific internal loading conditions is essential. The goal of this study was to calculate the lower limb muscles forces during the strength exercises deadlifts, goodmornings and splits squats by means of musculoskeletal simulation.Methods11 participants were assessed performing 10 different variations of split squats by varying the step length as well as the maximal frontal tibia angle, and 13 participants were measured performing deadlift and goodmorning exercises. Using individualised musculoskeletal models, forces of the Quadriceps (four parts), Hamstrings (four parts) and m. gluteus maximus (three parts) were computed.ResultsDeadlifts resulted highest loading for the Quadriceps, especially for the vasti (18–34 N/kg), but not for the rectus femoris (8–10 N/kg), which exhibited its greatest loading during split squats (13–27 N/kg) in the rear limb. Hamstrings were loaded isometrically during goodmornings but dynamically during deadlifts. For the m. gluteus maximus, the highest loading was observed during split squats in the front limb (up to 25 N/kg), while deadlifts produced increasingly, large loading over large ranges of motion in hip and knee.ConclusionsActing muscle forces vary between exercises, execution form and joint angle. For all examined muscles, deadlifts produced considerable loading over large ranges of motion, while split squats seem to be highly dependent upon exercise variation. This study provides key information to design strength-training programs with respect to loading conditions and ranges of motion of lower extremity muscles.

Highlights

To ensure an efficient and targeted adaptation with low injury risk during strength exercises, knowledge of the participant specific internal loading conditions is essential
M. vastus lateralis showed the highest forces followed by m. vastus medialis, m. vastus intermedius and M. rectus femoris (Table 1)
Since M. rectus femoris was only partially recruited in both exercises, but was constantly loaded in the rear leg of the split squats over the whole RoM (20° to 100°), the split squat exercise is recommended to strengthen this muscle, preferably using a large step length and a small tibial angle

Summary

Introduction

To ensure an efficient and targeted adaptation with low injury risk during strength exercises, knowledge of the participant specific internal loading conditions is essential. Computational models that are able to provide an insight into the internal loading conditions in the human musculoskeletal system [12] have become available using different software packages (e.g. OpenSim SimTK, LifeModelerTM, Anybody Modelling SystemTM, Biomechanics of Bodies). Such models are widely used in clinical and biomechanical gait analysis for studying lower limb dynamics as well as for investigating loading conditions in strength exercises [13,14,15,16]. An improved understanding of these muscle and joint contact forces, including the magnitude and the direction of the forces, is essential for appropriate prescription and modification of training exercises, as well as for improving rehabilitation outcomes [13, 17]

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