Hips Don't Lie: Analyzing Frontal Plane Kinematics In Adults Of Varying Ages During Step Tasks

Aging is linked to reduced physical activity, which can lead to a loss of strength and coordination. Previous research indicates that older individuals display greater asymmetries and altered kinematic patterns in fundamental movements, which can contribute to injury risk. PURPOSE: To assess the relationships between age and frontal plane kinematics of the hip and knee during step-up and step-down tasks. METHODS: Five of 75 participants have completed the study thus far: 2 males and 3 females, age 42.8 ± 15.4. Participants completed three single leg step-ups and step-downs on each limb from a 25 cm height while 2D frontal plane kinematics were recorded. Following informed consent, markers were placed bilaterally on anterior and posterior landmarks of the lower extremity. Video data were exported to Kinovea (v. 9.5), and contralateral hip drop and knee valgus angles were identified. The average maximum and minimum values of the dominant limb were calculated across trials. Range of motion (ROM) for each angle was calculated as the average minimum value minus the average maximum value. The relationships between age and hip drop ROM, age and knee valgus ROM, and age and symmetry were assessed using bivariate correlations (α = 0.05). RESULTS: Means and standard deviations are presented in Table 1. Initial findings indicate a strong positive correlation between age and contralateral hip drop (r = 0.14, p > 0.05). No correlations between age and knee valgus (r = 0.08, p > 0.05), age and hip drop symmetry (r = -0.21, p > 0.05) or age and knee valgus symmetry (r = -0.11, p > 0.05) were found. CONCLUSION: Based on these preliminary data, increased age may be associated with risky frontal plane hip kinematics. However, further testing on a broader age range is necessary. Continued evaluation of the remaining participants may provide additional insight into the proposed relationships.Supported by the ACSM NW Student Research Award. Table 1. - Observed Frontal Plane Kinematics Mean (SD) Symmetry Index* Right Left Contralateral Hip Drop (°) 22.9 ± 5.6 20.1 ± 8.7 13.0 Knee Valgus (°) 5.3 ± 2.7 8.4 ± 3.1 45.3 *(SI = (Xleft-Xright)/(0.5*|Xright| + |Xleft|)*100) ACSM Northwest Student Research Award