Isokinetic evaluation of trunk muscles

Area of Science:

• Biomechanics
• Musculoskeletal Health
• Exercise Physiology

Background:

• Back pain is a prevalent issue often linked to weak trunk muscles.
• Assessing trunk muscle strength dynamically is crucial for identifying at-risk individuals.
• Existing methods may not fully capture the dynamic strength and fatigue characteristics of trunk musculature.

Purpose of the Study:

• To develop a quantitative method for assessing the dynamic strength of trunk muscles.
• To identify individuals with weak trunk muscles who are prone to back pain.
• To analyze trunk muscle strength and fatigue in different populations and conditions.

Main Methods:

• Designed two unique isokinetic strength testing units for sitting and standing postures.
• Tested three groups of volunteers, measuring maximum strength and fatigue behavior.
• Quantitatively assessed abdominal, paraspinal, and iliopsoas muscle function across different age groups.

Main Results:

• Women exhibited lower maximum trunk strength but equal or superior fatigue endurance compared to men.
• Maximum strength demonstrated a significant age-related decline, with a bimodal distribution in abdominal strength changes.
• The iliopsoas muscle significantly enhanced maximum back strength in flexion (approximately doubled).
• Isokinetic testing in the sitting posture was better tolerated and found to be effective and safe.

Conclusions:

• Isokinetic testing in a sitting posture provides an effective and safe method for assessing trunk muscle strength.
• Understanding sex-based differences and age-related changes in trunk strength is vital for injury prevention.
• The iliopsoas muscle plays a critical role in dynamic trunk strength, particularly in flexion.