Musculoskeletal model-based inverse dynamic analysis under ambulatory conditions using inertial motion capture

Area of Science:

• Biomechanics
• Human Movement Analysis
• Computational Modeling

Background:

• Musculoskeletal modeling and inverse dynamic analysis are crucial for estimating joint, muscle, and ligament forces non-invasively.
• Conventional methods rely on optical motion capture (OMC) and force plates (FP), limiting analyses to controlled laboratory settings.
• This limitation restricts the widespread application of biomechanical models in real-world scenarios.

Purpose of the Study:

• To propose and validate a novel method for performing musculoskeletal model-based inverse dynamics using inertial motion capture (IMC).
• To develop a universally applicable ground reaction force and moment (GRF&M) prediction method compatible with IMC data.
• To overcome the spatial and logistical constraints associated with traditional OMC and FP systems.

Main Methods:

• Utilized inertial motion capture (IMC) as the primary input for inverse dynamic analysis.
• Implemented a novel, universally applicable prediction method for ground reaction forces and moments (GRF&M).
• Validated the IMC-based method against conventional optical motion capture (OMC) and force plate (FP) laboratory-based techniques.

Main Results:

• Excellent correlations (ρ=0.95-0.99) and low root-mean-squared-differences (RMSD) were observed for sagittal plane joint angles of the ankle, knee, and hip.
• The predicted GRF&M showed excellent correlations for vertical (ρ=0.97), anteroposterior (ρ=0.91), and sagittal (ρ=0.91) components.
• Strong correlations were found for mediolateral (ρ=0.80) and transverse (ρ=0.82) GRF&M components, with low RMSD values.

Conclusions:

• The proposed IMC-based inverse dynamics method effectively replaces traditional OMC and FP systems.
• This approach removes the complexity and space restrictions of laboratory-based setups.
• It enables broader applications of musculoskeletal modeling, including patient monitoring in daily life and expanded clinical practice.