imbalance of muscles around the knee can cause changes in the alignment of the knee 
 joint1 . therefore , to prevent knee 
 injuries in females , improved muscle balance around the knee during dynamic motions such as 
 landing and balanced strengthening of lower limb muscles are necessary . kim et al.1 found kinematic differences in landing 
 motions between male and female college students and reported that the valgus angles of 
 females were more increased than those of males during a vertical landing motion . the 
 decline squat exercise moves the line of gravity backwards and increases external momentum 
 during extension in knee joints2 ; thus , 
 the squat exercise on a decline board has had great effectiveness in reducing knee pain due 
 to the selective strengthening of lower extremity muscles3 . this study investigated the effect of the single - leg , lateral 
 oblique , decline squat exercise on sacroiliac ( si ) joint pain with knee pain . a 39-year - old female had severe pain in the right medial buttock and right anterior knee . she complained of continuous low back pain for 8 months , and examination revealed that her 
 pelvis was tilted posteriorly . the patient was unable to sleep in the side - lying position 
 due to the pain . the purpose and methods of the study were explained to the participant 
 before her inclusion in the study , and she provided informed consent according to the 
 principles of the declaration of helsinki . the pelvic inclination was measured with a 
 palpation meter ( palm ; performance attainment associates , st . paul , mn , usa ) by one 
 examiner . at the initial assessment , the anterior pelvic tilt angles were 3.5 and 6.5 on 
 the right and left sides ( normal range , 11  4 ) , respectively . on palpation of the right 
 medial buttock and right anterior patella , the visual analog scale ( vas ) scores were 7/10 
 and 6/10 , respectively . the si joint pain provocation tests used in this study were the 
 gaenslen test and patrick test . the single - leg , lateral oblique , decline squat exercise is 
 performed with descent to 90 knee flexion , followed by ascent to the initial position at 
 the individual s natural speed . this study assessed the anterior pelvic tilt angle and the response to 
 pain provocation tests before and after 4 weeks of performing the exercise . following the course of exercise , the anterior pelvic tilt angles were 8 and 10 on the 
 right and left sides , respectively , and were higher than the initial values ( 3.5 and 6.5 ) . on palpation of the right medial buttock and right knee , the initial vas scores of 7/10 and 
 6/10 decreased to 2/10 for both regions . the decline squat exercise induces anterior pelvic tilt as the trunk is pushed backward to 
 compensate for the feeling of the trunk tilting forward2 , 3 . the subject in the current study also experienced 
 considerable reduction in lateral knee pain , due to decreased tension in the tensor fasciae 
 latae or iliotibial band of the lateral knee . in particular , the pain in the si joint also 
 subsided after the course of exercise . the decline board used for the single - leg , lateral 
 oblique , decline squat exercise induced foot supination , which promoted ideal alignment of 
 the hip and pelvis , preventing knee valgus . in addition , the single - leg position can 
 activate muscles that provide pelvic stability more effectively than the two - leg 
 position4 . manual pelvic compression was 
 demonstrated to be a compensatory strategy to enhance the force closure mechanism and thus 
 normalize the altered motor responses5 . the stability of the si joint through form and/or force closure mechanisms was proposed to 
 facilitate load transfer to the pelvis5 . therefore , the single - leg , lateral oblique , decline squat exercise can be effective for 
 treating si joint pain with knee pain caused by an abnormal quadriceps angle in females .
[ purpose ] this study investigated the effect of the single - leg , lateral oblique , decline 
 squat exercise on sacroiliac joint pain with knee pain . [ subjects and methods ] a 
 39-year - old female had severe pain in the right medial buttock and right anterior knee . 
 this study assessed the anterior pelvic tilt angle and pain provocation tests before and 
 after single - leg , lateral oblique , decline squat exercise for 4 weeks . 
 [ results ] following 
 the course of exercise , the anterior pelvic tilt angles were increased , and the visual 
 analog scale pain scores for both the right buttock and right knee were 2/10 . [ conclusion ] 
 single - leg 
 , lateral oblique , decline squat exercise may be effective for treating si joint 
 pain with knee pain in females .