Iliopsoas strengthening increases hip joint forces during gait: A simulation study.

Area of Science:

• Biomechanics
• Orthopedics
• Human Movement Science

Background:

• Femoroacetabular impingement syndrome (FAIS) is a prevalent cause of hip pain in young, active individuals.
• Hip flexor weakness is common in FAIS and linked to poorer outcomes and joint damage.
• Current treatments for FAIS have variable success rates.

Purpose of the Study:

• To investigate differences in iliacus and psoas force production and joint contact forces (JCFs) during walking between individuals with FAIS and healthy controls (HCs).
• To simulate the effects of hip flexor strength and weakness on JCFs during walking.

Main Methods:

• Musculoskeletal modeling was employed to analyze hip flexor function.
• Simulations included five conditions of iliacus and psoas strength (50% to 150% of default).
• Statistical parametric mapping was used for group and strength condition comparisons.

Main Results:

• No significant differences in iliacus/psoas force or JCFs were found between FAIS and HC groups during walking.
• Increased hip flexor strength led to higher JCFs throughout the gait cycle.
• Decreased hip flexor strength resulted in lower JCFs, with varied effects during specific gait phases (preswing).

Conclusions:

• Hip flexor strength alterations significantly influence JCFs during walking in FAIS.
• Increasing hip flexor strength may yield more consistent effects on JCFs.
• Decreasing hip flexor strength demonstrates more variable impacts on JCFs across individuals and gait stages.