Objective To examine the association between concussion history and gait performance in collegiate American football players.

Design Case control.

Setting A first division collegiate American football team.

Participants Eighty-seven players belonging to a collegiate American football team in Japan were evaluated (age: 20.2±1.0 years, height: 174.3±6.3 cm, weight: 83.7±13.5 kg). Of them, 47 had no history of concussion (non-history), 21 had single concussion (single history), and 12 had multiple concussions (multiple history). Those with an existing lower extremity injury and self-reported memory or developmental disabilities were excluded.

Interventions (or Assessment of Risk Factors) Participants completed gait evaluations and medical history questionnaires. The single-task gait used tandem walking, and the dual-task gait included three cognitive tasks. A one-way analysis of variance and an analysis of covariance were conducted to compare gait performance among the three groups.

Outcome Measures Gait performance was evaluated based on gait time and maximum acceleration using a triaxial accelerometer attached at spina process of L5.

Main Results The average gait time was 14.2±2.8 seconds for single-task and 17.9±4.0 seconds for dual-task gait. In the latter, the maximum acceleration in the medial/lateral direction was significantly greater in the multiple history group than that in the non-history and single history groups (p=0.026). The maximum acceleration adjusted by single-task gait in the front/back direction was significantly greater in the multiple history group than that in the single history group (p=0.037).

Conclusions American football players with multiple concussions had greater maximum acceleration, suggesting that prior concussions may affect to gait pattern.