Quantifying passive resistance to motion in the straight-leg-raising test on asymptomatic subjects

• Published in: The Journal of the American Osteopathic Association Vol. 93; no. 9; p. 913
• Main Authors: Reynolds, H M, Beal, M C, Hallgren, R C
• Format: Journal Article
• Language: English
• Published: United States 01-09-1993
• Subjects: Adolescent; Adult; Algorithms; Anthropometry; Biomechanical Phenomena; Female; Hip Joint - physiology; Humans; Isometric Contraction; Leg - physiology; Male; Mathematics; Middle Aged; Range of Motion, Articular
• ISSN: 0098-6151
• DOI: 10.7556/jaoa.1993.93.9.913

The clinician needs an objective way to measure limb motion in the straight-leg-raising test. A biomechanical algorithm was used to quantify resistance to motion in 15 asymptomatic subjects. Measurements from a pendulum electrogoniometer and hand-held load cell were used to calculate a moment representing passive resistance to motion. After three measurement trials, significant increases in range of motion (4.7%) and moment (8.4%) occurred. Then, an isometric contraction-relaxation of the hip extensors produced a highly significant increase in motion (8.8%) but decrease in moment (< 14.3%). A third order polynomial fit of moment per angle stratified the sample into two groups according to their change in moment. Motion in group 1 increased 8.0%, and in group 2, 9.5%. However, group 1 had no change in moment whereas group 2 had a highly significant decrease in moment (22.9%). The measured change in resistance demonstrated that a simple biomechanical algorithm quantified properties in a clinical test that were not observed in range of motion alone.