MATHEMATICAL MODELING OF PELVIC MUSCLE FUNCTION IN PATIENTS WITH HIP JOINT ADDUCTION CONTRACTURE AT SINGLE-SUPPORT STANDING

Long existing hip arthritis is accompanied by the development ofpain and contractures that cause contractile muscle spasm, reductionin length of adductor muscles flexors thigh,relative overstretching abductor muscles, which over timeleads to changes in their structure. The result weakness thepelvic clinical manifestation a violationof postural balance — lameness, torso tilts while walking, changesin pelvic position, etc. Objective. To determine effect thehip joint adduction contracture on ability maintain balancestanding position with mathematical model. Methods: mathematicalmodel worked out represents pelvis thigh andthe vectors action muscles. Themuscular effort required body during one-legstanding was normal set at 5° 10°.Calculations were performed for patients weighing 70; 100; 120 kg.Results. It determined 5°m. gracilis, m. add magnus, piriformis are not able performthe functions maintaining due necessity todevelop greater efforts than maximum possible, even theminimal patient's weight. If weight exceeds kg, thenalmost entire muscular system stabilization worksbeyond its capabilities. 10° increasesthe force stabilizer absolute valuesshowed an increase strength indicators. Conclusions.The causes change thebiomechanical conditions inthe angles reducing effectivenessof work stabilize pelvis. As angle adductioncontracture increases, there tendency musclesto effectively. An additional factor negatively affects thisindicator overweight.