A quantitative comparison of two kinematic protocols for lumbar segment motion during gait

Area of Science:

• Biomechanics
• Gait Analysis
• Kinematics

Background:

• Lumbar motion tracking in gait analysis uses 2D or 3D methods.
• 3D analysis often treats the lumbar region as a rigid segment for inverse dynamics.
• Protocol selection currently relies on clinical experience, lacking standardized validation.

Purpose of the Study:

• To assess the impact of two different 3D lumbar segment protocols on gait kinematic output.
• To compare the agreement and similarity of kinematic data derived from distinct 3D tracking methods.
• To guide the selection of appropriate lumbar tracking protocols for research and clinical applications.

Main Methods:

• Simultaneous gait data recording using two 3D lumbar kinematic protocols.
• Protocol 1: Skin surface rigid protocol with markers across the lumbar region.
• Protocol 2: Rigid cluster with active markers over the L3 vertebra.

Main Results:

• The skin surface protocol exhibited lower overall variability in 4 out of 6 kinematic measures.
• Ensemble average graphs showed similar mean kinematic profiles between protocols.
• Functional Limits of Agreement and waveform similarity (CMC) indicated poor to moderate agreement between the two protocols.

Conclusions:

• The choice of 3D lumbar tracking protocol significantly influences kinematic output during gait.
• The skin surface protocol may be preferable for studies focusing on axial rotation due to lower variability.
• Standardized protocols are needed to ensure consistency and reliability in lumbar kinematic analysis.