Football Shoulder Pad Design and Its Effect on Head Kinematics in Shoulder-to-Helmet Impacts.

Shoulder-to-helmet (STH) impacts have been shown to cause approximately twenty percent of concussions in football yet little research has investigated shoulder pad design and STH impacts. This study aimed to characterize STH impacts and identify the effect of shoulder pad design on the struck head kinematics. Additional padding was added to a shoulder pad, and was then compared to an unmodified control shoulder pad. Participants performed a series of tests where they struck a helmeted Hybrid III dummy with both shoulder pad variations to compare struck head linear and rotational kinematics. The study found the modified shoulder pad reduced peak linear acceleration by 31% (Δµ = - 9.13 g's (- ∞, - 7.25), (p = 4.10e-08)), rotational acceleration by 28% (Δµ = - 565 rad s(- ∞, - 435), (p = 2.10e-07)), peak rotational velocity by 10% (Δµ = - 2.42 rad s (- ∞, - 1.54), (p = 6.9e-05)), and increased impact duration by 40% (Δµ = 9.96 ms (8.06, ∞), (p = 1.142e-08)). Impact response corridors were developed for both shoulder pad conditions and can be used to establish a controlled lab test setup that replicates STH impacts. Our findings suggest that shoulder pads have the potential to reduce head injury in football and warrant further research.