Lumbar Extension during Stoop Lifting is Delayed by the Load and Hamstring Tightness.

Area of Science:

• Biomechanics
• Kinesiology
• Ergonomics

Background:

• Stoop lifting is a common activity that can lead to lower back pain.
• The lumbar pelvic rhythm plays a crucial role in the biomechanics of lifting.
• Understanding the factors influencing this rhythm is essential for injury prevention.

Purpose of the Study:

• To investigate the relationship between lumbar pelvic rhythm and physical characteristics during stoop lifting.
• To determine how load and hamstring flexibility affect lumbar pelvic rhythm during lifting tasks.

Main Methods:

• Participants performed stoop lifting with and without load.
• Lumbar kyphosis and sacral inclination angles were measured using the SpinalMouse(®) system.
• Hamstring flexibility, electromyograms, and lumbar/sacral motion were recorded.

Main Results:

• Load delayed lumbar extension during the initial lifting phase.
• Delayed lumbar extension correlated negatively with sacral inclination angle and positively with lumbar multifidus activity.
• Sacral inclination angle correlated positively with hip flexion range of motion.

Conclusions:

• Disrupted lumbar pelvic rhythm can result from load and hamstring tightness.
• Delayed lumbar extension during stoop lifting increases spinal instability and posterior ligament stress.
• Stoop lifting with load may pose a risk to the lower back in individuals with hamstring tightness.