Hip joint mobility in relation to measurement position, gender and limb dominance.

Purpose: The purpose of this study was to determine whether three different measurement position yield divergent results in ROM using a goniometer, and how is it affected by anthropometrical factors.

Methods: We measured the range of rotation in the hip joint in healthy participants aged 21.6 ± 1.88, seeking to determine how the distribution of internal vs. external rotation (RI) within the total range of mobility (TR) was influenced by the measurement position used, the gender of the participant, and the dominant lower limb.

Results: We found that not only gender and limb dominance, but also the body position in which hip joint's range of motion is measured significantly affects the values of TR and RI. We found that TR achieves the highest values in the prone position - PrP (males: 95.35 ± 12.44 and 93.15 ± 12.49; females: 103.75 ± 14.87 and 106.25 ± 15.56) and the lowest values in supine position - SuP (male: 62.65 ± 8.51 and 57.85 ± 9.60; female: 59.5 ±12.27 and 55.85 ±8.54). The analysis shows that CERD occurs <0.42 RI in females (PrP) and <0.88 RI in men (PrP and sitting position - StP), and CIRD > 1.72 RI in women (StP), and > 2.08 RI in men (PrP).

Conclusions: Due to the similarities between asymmetry of internal/external rotation in the hip joint and asymmetry in the rotation of the shoulder found in Glenohumeral Internal Rotation Deficit (GIRD), we propose the concepts of Coxal Internal Rotation Deficit (CIRD) and Coxal External Rotation Deficit (CERD) as tools to indicate the possibility for injury to the hip joint, and propose threshold rotation index values serving as indicators of these deficits.