Investigation of the Functional and Biomechanical Effect of Instrument Assisted Soft Tissue Mobilization Technique in Individuals With Asymptomatic Dynamic Knee Valgus - Randomized Controlled Trial

Introduction Dynamic knee valgus (DDV), one of the lower extremity faulty movement patterns, is a biomechanical deviation that occurs in 3 motion plans, involving femoral internal rotation (FIR) and contralateral pelvis fall simultaneously with hip adduction.1 Hip flexion, adduction and FIR moments occur simultaneously during loading phase of walking, running or landing after jumping. Combination of these moments also forms DDV. These moments are resisted by intrinsic moments caused by eccentric contractions of hip extensor, abductor and external rotator muscles. Strength deficiency of these muscles in weight transfer activities causes an increase in hip adduction, and FIR, changes whole lower extremity kinematics.2,3 The valgus alignment also increases the risk of injury.4 In the review examining relationship between hip muscle strength and DDV, it was determined that decrease in gluteus medius (GMed) strength in functional activities on single leg was associated with DDV.2 Abduction torque produced by hip abductors stabilizes pelvis on relatively fixed femur by controlling pelvis in frontal and horizontal planes during stance phase of walking and most of stance and GMed produces most of the compression forces in hip.3,5 Therefore, GMed strength is also very important for postural stability (PS). In individuals with DDV, strength of hip muscles, especially GMed, should be focused on increasing PS during the tests performed on single leg and in injury prevention programs.4,6 Anatomical features of women increase the risk of DDV. In addition, when gender comparison was made, it was seen that women needed more eccentric contraction in the hip abductor muscles during the stance phase of running.7, and strength deficiency in proximal hip stabilizers of females could cause a greater decrease in athletic performance compared to men.8 Therefore, evaluation of eccentric strength of GMed muscle should be evaluated specific to gender.2 Thus, a more precise conclusion can be found in terms of abductor muscle strength, DDV and lower extremity alignment.

Effect of soft tissue mobilization techniques on force production and performance is a remarkable topic. Instrument-assisted soft tissue mobilization (IASTM) technique, one of the soft tissue mobilization techniques, has also been found to be effective method that affects muscle strength, performance and endurance through activation of muscle and nervous systems.9-11 However, in studies IASTM technique was applied with an exercise protocol, and contribution of IASTM in force generation and performance increase is not understood.

According to our knowledge, in the literature there is no randomized controlled study examining the effect of IASTM applied without exercise. Aim of our study is to investigate changes caused by IASTM applied to GMed muscle on eccentric force production of GMed, FIR, frontal plane projection angle (FPPA) and PS.