Evaluation of Lifting Techniques Using Optoelectronic Systems with Knee Range of Motion Restrictions

Area of Science:

• Biomechanics
• Human Movement Science
• Musculoskeletal Research

Background:

• The kinetic chain approach emphasizes regional interdependence, where altered joint mechanics in one area can affect adjacent segments.
• Understanding how knee impairments influence the spine and posterior chain is crucial for managing musculoskeletal conditions.

Purpose of the Study:

• To investigate the impact of knee range of motion (ROM) restrictions on lumbar spine kinematics and posterior chain muscle activity during squat and stoop lifting.
• To explore compensatory mechanisms within the kinetic chain in response to simulated knee deficits.

Main Methods:

• Fifteen healthy adults performed squat and stoop lifts under varying knee ROM conditions (e.g., free, 0-60°, 0-90°).
• Optoelectronic motion capture and electromyography (EMG) were used to record lumbar spine motion and posterior chain muscle activation.
• One-way ANOVA analyzed differences in lumbar spine angles and muscle activation patterns.

Main Results:

• No significant changes were found in lumbar spine flexion/extension or side bending due to knee ROM restrictions (p > 0.15).
• Pelvic rotation significantly differed across knee ROM conditions (p = 0.0103).
• EMG data revealed increased activation in the Gastrocnemius Lateralis and Biceps Femoris (p < 0.001), with no change in Gluteus Maximus or Latissimus Dorsi.

Conclusions:

• Knee ROM restrictions induce localized compensatory responses, altering pelvic rotation and distal muscle activation patterns.
• These findings provide insights into how knee impairments may influence lifting mechanics and suggest potential adaptations relevant to conditions like osteoarthritis or low back pain.