Related Experiment Video
Updated: May 18, 2026

Construction of a Realistic, Whole-Body, Three-Dimensional Equine Skeletal Model using Computed Tomography Data
Published on: February 25, 2021
Three dimensional musculoskeletal modelling of the abdominal crunch resistance training exercise
Kim Nolte1, Pieter E Krüger, P Schalk Els
1University of Pretoria, Biokinetics, Sport and Leisure Sciences, LC de Villiers Sports Centre, South Street, Hatfield, Pretoria, 0002, South Africa. kim.nolte@up.ac.za
Abstract:
The aim of this study was to evaluate the benefits and limitations of using three dimensional (3D) musculoskeletal modelling (LifeModeler) in assessing the safety and efficacy of exercising on an abdominal crunch resistance training machine. Three anthropometric cases were studied, representing a 5th percentile female, and 50th percentile and 95th percentile male. Results indicated that the LifeModeler default model was capable of solving the forward dynamics simulations without adjustments. The modelling was able to indicate high risk for back injury when performing the abdominal crunch exercise as a result of the unacceptable intervertebral joint loading that occurs during the exercise. Individuals with small anthropometric dimensions such as some females and children cannot be accommodated suitably on the abdominal crunch machine which negatively impacts exercise posture and technique. Hip flexor muscle contribution in the execution of the exercise for the 5th percentile female was substantial thus reducing the efficacy of the exercise in isolating the abdominal muscles.
Related Concept Videos
Muscles of the Abdomen
Anterolateral Region
The anterolateral region comprises five paired muscles classified into the lateral and anterior...
Muscles of the Thorax
The diaphragm is at the core of thoracic musculature, the primary muscle involved in breathing. This expansive, dome-shaped muscle marks the division between the thoracic and abdominal cavities. It originates...
Three-Dimensional Force System
Axial and Appendicular Muscles
Axial Muscles
Axial muscles, situated along the body's midline, are intricately connected to the axial skeleton, which includes the skull, spine, ribs, and sternum. These muscles facilitate facial expressions and play a...

