843 MEP172 – Pilot study investigating effects of two athletic shoe types on ground contact loads and dynamic valgus during three change of direction tasks

AbstractBackground Shoe design is a modifiable risk factor in non-contact lower-limb injury. Yet, we have limited understanding how shoe design relates to change-of-direction (CoD) movements.Objective Quantify how different athletic shoes affect contact kinetics and dynamic valgus among three CoD tasks (Split-dodge, Zig-zag, Shuttle). We hypothesized greater at-risk angles and loads in Cleated shoes.Design A cross-sectional comparative study received institutional ethics approval. Each participant was measured at a single visit.Participants Our target is 10 female and 10 male healthy athletes 18 to 25 years old. Exclusion: history of joint, nerve, or muscle disease, and prior injury or surgery within six months. Interventions See Figure 1. Participants performed three CoD tasks: a 45° Split-dodge, a 100° Zig-zag, and 180° Shuttle. All tasks were repeated on FieldTurf wearing Nike Alpha Huarache lacrosse Cleats and Turfs. Marker-based kinematics and kinetics were measured over force plates at 200 Hz. Shoe and task order were randomized.Measurements Speed at contact, initial peak force, distal limb work; 50 milliseconds after contact: hip adduction, foot-to-pelvis progression, and shoe-to-shank inversion. Paired non-parametric statistics compared shoe type, stratified by dominance. Results Eight participants (6F, 2M) have completed testing, see Table 1. Shuttle speeds were slower (P<0.05) for Cleated non-dominant limbs. Shuttle peak force was lower (P<0.01) in Cleated non-dominant limbs. Shuttle hip adduction was greater (P<0.05) in Turf dominant limbs. Zig-zag external foot progression was decreased in Turfs for dominant limbs (P<0.01) and Shuttle non-dominant limbs (P<0.05). Shoe inversion was decreased in Turf dominant limbs for Split (P<0.05), Zig-zag (P<0.01), and Shuttle (P<0.05). Distal work was not different among tasks.Conclusions Contrary to expectations, Turfs were associated with higher-injury-risk biomechanics. Also, more biomechanical differences were noted in the Shuttle task. This laboratory-based work is still preliminary and data collection ongoing. Additional work is required and should explore real-world scenarios.View this table:View inline View popup Download powerpoint Abstract 843 Table 1 Biomechanical metrics (N=8) are stratified by task, dominance, and shoe type, values given as Mean + SD. D=Dominant limb, ND=Nondominant limb. Statistically significant one-tailed differences via Wilcoxon Signed-Rank tests comparing Turf and Cleat shoe conditions: + P<0.05, $ P<0.01. Direction aligned with hypothesis; Direction not aligned with hypothesisDownload figure Open in new tab Download powerpoint Abstract 843 Figure 1