Correlation Between Pelvic Tilt Angle, Hip Range Of Motion And Hip Muscles Torque Ratios

Abstract

Anterior pelvic tilt is associated with excessive foot pronation, excessive hip internal rotation (HIR), and knee valgus, which may lead to hip muscles strains, sciatic nerve compressions, and sacroiliac and lumbosacral joint instability. Posterior pelvic tilt is associated with feet supination and increased hip external rotation (HER), which may lead to tibial stress fractures, medial tibial stress syndrome, knee pain, anterior cruciate ligament injury, and low back pain. Hip adductors/abductors (add/abd) torque ratio (TR) below 80%, was associated with adductor strains. The average hip flexors/extensors (flex/ext) TR in sport performance was found to be 70%. There is a lack of evidence that correlates pelvic tilt angle with limited HIR, HER, add/abd TR, and flex/ext TR. PURPOSE: to examine the correlation between natural pelvic tilt angle and HIR, HER, add/abd TR, and flex/ext TR. METHODS: Twenty-six subjects participated in this study, fifteen females (22.0±2.8 years old, 163.5±7.5 cm, 65.9±10.4 kg) and eleven males (22.0±2.2 years old, 178.5±4.5 cm, 78.4±8.7 kg). Using a 3D motion analysis system, the measurement of both natural pelvic tilt (NPT) in standing natural position and HIR and HER in lunge position, for the right and left limbs, were recorded. Hip torques were collected with an isokinetic dynamometer, five trials at 30 deg/s and at 60 deg/s. RESULTS: The mean value for NPT was 5.7±5.4 deg. There were no significant correlations between NPT and the dependent variables for the right limb: HIR (r=-0.16, p=0.43), HER (r=-0.11, p=0.58), add/abd TR at 30 deg/s (r=-0.19 p=0.34), add/abd TR at 60 deg/s (r=-0.13 p=0.51), flex/ext TR at 30 deg/s (r=0.32 p=0.10) and flex/ext TR at 60 deg/s (r=-0.70 p=0.70). Similar results were observed for the left limb: HIR (r=-0.20, p=0.89), HER (r=-0.25, p=0.21), add/abd TR at 30 deg/s (r=-0.17 p=0.38), add/abd TR at 60 deg/s (r=-0.12 p=0.55), flex/ext TR at 30 deg/s (r=0.60 p=0.75) and flex/ext TR at 60 deg/s (r=-0.19 p=0.33). CONCLUSION: the measurement of NPT angle in standing natural position is not a good predictor of HIR, HER, add/abd TR, and flex/ext TR. Future research should look at these relations during functional dynamic movements and during pelvic tilt end range of motion.