Background and aim: Active straight leg raise test in patients with sacroiliac joint dysfunction (SIJ ) is accompanied by feeling pain on joint or heaviness and inability to lift the leg. This test has been advocated as reliable and valid test for the quality of load transfer through the lumbo-pelvic region. With respect to the important role of muscles, in pelvic stability and with respect to patients with SIJ dysfunction can not do this test easily. There is no study has been done about assessment and comparison  of changes in muscle timing of pelvic stabilizer muscles and duration of ramping time during ASLR between healthy and patients with SIJ dysfunction 

Materials and methods:Eleven female subjects with clinical diagnosis of sacroiliac joint pain and 15 match healthy female subjects were tested in the supine resting position with the ASLR. Surface electromyography of rectus abdominus , oblique externus , oblique internus  , adductor longus , biceps femoris , gluteus maximus and  erector spine muscles  were recorded during ASLR test. Timing of muscles and ramp time during ASLR  test were acquired and measured in MATLAB software . 

Results: No statistically significance were found in ramp time between two groups. The onset timing of activation of adductor longus (A.L) was delayed on symptomatic side in subject with SIJ pain (P=0.006).

Conclusion: Delayed onset of A.L suggests an alteration in strategy for lumbopelvic stabilization that may disrupt load transfer through the pelvis.

Background and Aim: Sacroiliac joint (SIJ) is one of the most important elements in normal musculoskeletal function during gait cycle and serve as a shock absorber during heel strike and load transfer from lower limbs to trunk. Its stabilizing is the product of osseous, ligamentus and muscular elements which muscle activity of these muscles (Gluteus Maximus, Biceps Femoris, Multifidus, Erector Spinea, and Latissimus Dorsi) is important in load transfer through SIJ. It seems that the function of the given muscles in sacroiliac joint pain subjects is interrupted. So, the aim of the present study is to compare muscle activity during different events of stance phase of gait cycle during preferred and slow speed between sacroiliac joint pain and healthy subjects.

Methods and Materials: Thirteen SIJ pain subjects (12 females, 1 male) and thirteen healthy subjects (11 females, 2 male) participated in this study. Muscle activity based on RMS from selected muscles was recorded during different events of stance phase of gait either preferred or slow speed by EMG Data-link Biometrics and normalized according to muscle activity during a 500 ms period in rest position before starting walking called Baseline Correction.

Results: Significant statistical differences were found between two groups in muscle activity based RMS during different events of stance (p=0/006), but there was no significant difference in effect of speed on RMS between two groups (p=0/37). Significant Statistical differences were also seen between selected muscles in each group separately during slow speed of walking (p=0/003) but no significant statistical difference during preferred speed in SIJ pain group (p=0/14).

Conclusion: SIJ subjects have showed increased levels of muscle activity during different events of stance phase of gait with preferred and slow speeds. These increased levels can be interpreted as a mechanism to control trunk movements effectively, provide sufficient support and transfer load to lumbar area efficiently.

Key words: Muscle activity, Sacroiliac joint, Gait, Trunk muscle, Lower limb muscles

Background and Aim : Trauma or micro-trauma over prolonged period of time can lead to

  pathoanatomical changes and passive instability of the sacroiliac joint. These subjects often reluctant to bear full weight through the impaired side of the pelvis. The aim of this study was to investigate the effect of exercise therapy on symmetric distribution of weight in sacroiliac joint instability in standing and walking through Alfoot device.

Materials and Methods : In this study, 17 subjects with sacroiliac joint instability with age range of 20-40 years were selected by simple sampling. Subjects performed a single session of training that involve five tasks in 3 sets, including sitting on gym ball, lying on gym ball, quadruped, standing near wall and standing on tilt board. Before, immediately after, 5 and 10 minutes after intervention , scanning the both feet were recorded during standing and walking.

Results : The amount of weight on both feet in bipedal stance position were significantly different before and immediately after the intervention. But this difference , 5 minutes (p =0.058) and 10 minutes (p =0.110) was not significantly different after exercise therapy. The pressure on the middle part of the foot during walking significantly increased immediately after the intervention and it continues up to 10 minutes .

Conclusion : The results of this study suggest that training of lumbopelvic muscles can be an effective way to improve weight distribution on the affected side in patients with sacroiliac joint instability .