Head Control and Upper-Body Coordination during Gait in Collegiate Contact and Noncontact Athletes.

Persistent contact sport participation exposes athletes to repetitive head impacts, eliciting lingering motor performance alterations that could disrupt visual perception. We sought to compare head and trunk displacement, segmental coordination, and dynamic visual acuity between contact (ice hockey) and noncontact (baseball) athletes. Thirteen ice hockey and 11 baseball athletes walked at preferred and fast speeds during both a baseline and an imposed dynamic visual acuity (DVA) task. With increased visual task constraints and walking speeds, greater vertical head (preferred walking with visual task: 4.29 ± 0.48 vs 3.69 ± 0.71 cm,  = 0.030; fast baseline walking: 5.91 ± 0.59 vs 5.00 ± 0.97 cm,  = 0.019; fast walking with visual task: 5.72 ± 0.62 vs 4.86 ± 0.79 cm,  = 0.005) and trunk CoM displacement (fast baseline walking: 5.84 ± 0.61vs 5.00 ± 0.95 cm,  = 0.026; fast walking with visual task: 5.65 ± 0.63 vs 4.89 ± 0.78 cm,  = 0.014) were observed in contact athletes. In the transverse head-trunk coordination, contact athletes showed a decreased contribution of the head (9.85 ± 5.57 vs 19.36 ± 9.84%,  = 0.007) and increased trunk involvement (47.31 ± 21.43 vs 33.64 ± 10.79%,  = 0.030) compared to noncontact athletes, but this occurred only during fast walking with the DVA task. No DVA differences were observed (preferred speed:  = 0.650; fast speed:  = 0.820). While visual task performance was unaffected by contact sport status, the current results demonstrate changes in upper-body movement and how the head and trunk are coordinated in ice hockey athletes. Whether the observed upper-body movement and coordination changes due to repetitive head impact exposure result in decrements in visual perception and awareness in more challenging sporting environments remains unclear.