Related Experiment Video
Updated: Dec 23, 2025

09:32
Subject-specific Musculoskeletal Model for Studying Bone Strain During Dynamic Motion
Published on: April 11, 2018
10.1K
Statistical Modeling of Lower Limb Kinetics During Deep Squat and Forward Lunge
Joris De Roeck1, J Van Houcke1, D Almeida2
1Department of Human Structure and Repair, Ghent University, Ghent, Belgium.
Frontiers in Bioengineering and Biotechnology
|April 18, 2020
Summary
This study developed a reliable statistical model for analyzing hip and knee joint forces during squats and lunges. The model accurately captures inter-individual variability in joint kinetics for personalized orthopedic therapies.
Area of Science:
- Biomechanics and Human Motion Analysis
- Orthopedic Research
- Computational Modeling and Statistics
Background:
- Quantitative human motion analysis has extensively studied gait, but descriptions of complex movements like squats and lunges are limited.
- High forces on hip and knee joints during these movements contribute to significant morbidity and healthcare costs.
- Pre-surgical kinetic data acquisition on patient-specific anatomy is scarce, hindering personalized treatment strategies.
Purpose of the Study:
- To develop novel statistical models for analyzing hip and knee joint kinetics during squat and lunge movements.
- To investigate inter-patient variability in joint forces for challenging movements beyond gait.
- To lay the groundwork for personalized orthopedic therapies by understanding normal kinetic variations.
Main Methods:
- Fifty healthy young males performed squat and lunge trials, with spatial marker trajectories and ground reaction forces recorded.
- Data were imported into the Anybody Modeling System using subject-specific geometry and the TLEM 2.0 dataset.
- Inverse dynamics simulations were used to calculate hip and knee joint reaction forces, followed by principal component analysis for statistical modeling and variance decomposition.
Main Results:
- Average knee reaction forces reached up to 7.16 times body weight during the lunge (forward leg).
- Squatting resulted in an even distribution of load across joints.
- Compact and reliable statistical models were created, capturing 95.26% (lunge) and 95.69% (squat) of inter-individual variance with principal components.
Conclusions:
- The developed statistical model is compact, accurate, and reliable for analyzing squat and lunge kinetics.
- A minimum sample size of 50 participants is recommended for descriptive population studies.
- This approach enables a deeper understanding of inter-individual kinetic variability, supporting personalized orthopedic interventions.

