Trunk, Hip and Knee Motions During a Step-Down Test and Running in Patellofemoral Pain Individuals

Context: A common knee injury in runners is patellofemoral femoral pain syndrome (PFPS). The step-down test (SDT) is used to analyze lower extremity motions in runners with PFPS because kinematics are similar for the SDT and running. Individuals with PFPS often experience altered kinematics when compared to healthy. However, there are no known studies that examine the relationship in kinematics between the SDT and running. Objective: Examine the relationship between lower extremity kinematics of the knee, hip and trunk in runners with PFPS and healthy controls, during the midstance of running and during a SDT. Patients or Other Participants: Sixteen individuals 8 PFPS, 4 females (mean ± SD age, 28.5 ± 3.1 years; height, 173.0 ± 6.3 cm), and 8 healthy controls, 4 females (mean ± SD age, 30.12 ± 6.5 years; height, 171.09 ± 9.7 cm) distance runners. Intervention(s): A 10-minute treadmill running trial and a bilateral single leg SDT. Main Outcome Measure(s): Joint angles were recorded with a 3D motion capture system for both tests. Angles included lateral pelvic tilt (LPT), lateral trunk flexion (LTF), knee valgus (KVALGUS). Results: An excellent to moderate relationship between the SDTmax and midstance of running for LTF (r \u3c 0.89), KVALGUS (r \u3c 0.94), LPT (r \u3c 0.68) were observed. No significant differences in LTL (p \u3c 0.254), KVALGUS (p \u3c 0.069) and LPT (p \u3c 0.476) between groups and condition. There was a significant difference of condition between the run, and SDTmax observed in LTL (p = 0.034), but not significant in, KVALGUS (p = 0.051), and LPT (p = 1). Conclusions: The midstance phase of running and SDT shows a strong positive relationship and can be useful during clinical evaluation