The National Hockey League (NHL) mandated a recent change to the material used in shoulder pads for professional ice hockey players. It has been hypothesized that bigger and harder materials may be one of the causes of increases in the risk of head injuries, by enabling the athletes to collide at higher velocities. This has led the NHL to propose changes involving the removal of plastic caps and reducing the overall size of the shoulder pads. The purpose of this research was to examine how these changes to the design of shoulder pads might influence the peak resultant linear and rotational head acceleration incurred in a shoulder-to-head impact. A helmeted Hybrid III headform was impacted at the front center of gravity using a linear impactor at 6.5 m/s and 7.5 m/s. The impactor cap was fitted with three different shoulder pad conditions: a Pro shoulder pad with a plastic cap; a Pro shoulder pad with no plastic; and a Pro shoulder pad with an expanded polypropylene (EPP) foam cap, which is smaller than the standard Pro shoulder pad. The peak resultant linear acceleration results at 6.5 m/s showed that the EPP cap had the highest value of 112 g and the Pro pad with plastic had the lowest (100 g). At 7.5 m/s the EPP cap had the lowest value (127 g) and both Pro pads (with and without plastic cap) had the same value (141 g). For peak resultant rotational acceleration, the EPP cap had the lowest values at 6.5 m/s (5882 rad/s²) and 7.5 m/s (7358 rad/s²) when compared to the other shoulder pads. These results show that the design of protective equipment can be used to lower the peak linear and peak rotational acceleration incurred by the head during an impact. In conclusion, a smaller shoulder pad may be more effective at reducing rotational accelerations that are associated with the risk of concussion.