Sacroiliac joint dysfunction patients exhibit altered movement strategies when performing a sit-to-stand task

Publication date: Available online 3 April 2018
Source:The Spine Journal
Author(s): Robyn A. Capobianco, Daniel F. Feeney, Jana R. Jeffers, Erika Nelson-Wong, Joseph Morreale, Alena M. Grabowski, Roger M. Enoka
Summary of background dataThe ability to rise from a chair is a basic functional task that is frequently compromised in individuals diagnosed with orthopedic disorders in the low back and hip. There is no published literature that describes how this task is altered by sacroiliac joint dysfunction (SIJD).PurposeTo compare lower extremity biomechanics and the onset of muscle activity when rising from a chair in individuals with SIJD and healthy persons.Study designSix women with unilateral SIJD and six age-matched healthy controls performed a sit-to-stand task while we measured kinematics, kinetics, and muscle activity.MethodsSubjects stood up at a preferred speed from a seated position on an armless and backless adjustable stool. We measured kinematics with a 10-camera motion capture system, ground reaction forces for each leg with force plates, and muscle activity with surface electromyography. Joint angles and torques were calculated using inverse dynamics. Leg loading rate was quantified as the average slope of vertical ground reaction force during the 500-ms interval preceding maximal knee extension.ResultsBetween-leg differences in loading rates and peak vertical ground reaction forces were significantly greater for the SIJD group than the control group. Maximal hip angles were significantly less for the SIJD group (p = 0.001). Peak hip moment in the SIJD group was significantly greater in the unaffected leg (0.75 ± 0.22 N•m/kg) than the affected leg (0.47 ± 0.29 N•m/kg, p = 0.005). There were no between-leg or between-group differences for peak knee or ankle moments. The onset of activity in the latissimus dorsi muscle on the affected side in the SIJD group was delayed and the erector spinae muscles were activated earlier than in Controls.ConclusionsIndividuals with SIJD have a greater vertical ground reaction force on the unaffected leg, generate a greater peak hip moment in the unaffected leg, use a smaller range of motion at the hip joint of the affected leg, and delay the onset of a key muscle on the affected side when rising from a seated position.



https://ift.tt/2uF3Hne