The influence of three different test positions and thigh asymmetry on measurements of isometric hip flexion strength in men and women.

PURPOSE: The aim of this study was to compare muscle strength at 90° hip and knee flexion as measured in three different positions and to investigate whether an internal or external deficit in the range of rotation in the hip joint affects flexor muscle strength. METHODS: We measured the peak muscle torque of rotation in the hip joint, using isometric torquemeter, and hip ROM in healthy participants N = 40, aged 21.6 ± 1.9, in three different measurement positions. We tested for differences between the positions, and for the potential influence of participant's sex and ROM asymmetry. RESULTS: The measured peak muscle torque was affected not only by sex and the value of hip flexion affect, but also by the position in which it is measured. Subjects with restricted external rotation of the hip joint (CERD) had significantly higher flexor peak muscle torque compared to subjects with restricted internal rotation (CIRD), in all but the supine position. For CERD, the results were: Supine (SuP) 1.02 ± 0.26; Sitting (StP) 1.32 ± 0.58; Standing (SP) 1.53 ± 0.47; and for CIRD, the results were: Supine (SuP) 1.05 ± 0.17; Sitting (StP) 1.05 ± 0.40; Standing (SP) 1.47 ± 0.53. CONCLUSIONS: Overall, measurement position and passive ROM significantly influence the peak muscle torque in isometric conditions. Moreover, an imbalance in thigh rotation movement significantly determines the magnitude of muscle torque of the hip flexion movement. Individuals with increased internal-toexternal rotation achieved significantly higher values for flexor muscle torque force moments. Overall, these findings are of importance for interpreting or comparing any reported values for muscle torque force moments.

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.