Objective To compare head impact severity between high and low performers on baseline neurocognitive and balance assessments in collegiate American football athletes.

Design Prospective cohort.

Setting On-field/Concussion Research Laboratory.

Participants Thirty collegiate American football players (height: 187.0 cm, 95% CI: 184.6, 189.4; mass: 105.4 kg, 95% CI: 99.3, 111.6; age: 21.0 years, 95% CI: 20.5, 21.5).

Interventions Participants completed a baseline neurocognitive assessment (Immediate Post-Concussion Assessment and Cognitive Test) and balance exam (Sensory Organization Test). Participants wore accelerometers (Head Impact Telemetry System) to capture measures of severity for 13,537 head impacts.

Outcome measures Groups were divided into higher and lower performance groups using a median split for independent variables including composite neurocognitive (verbal memory, visual memory, processing speed, reaction time and impulse control) and balance performance. Random intercepts general linear models were used to compare linear acceleration (g), rotational acceleration (rad/s2), and Head Impact Technology severity profile (HITsp-unitless) between higher and lower performing groups (α=0.05). Position group was included in all models.

Main results Athletes with slower reaction time had a trend towards higher linear acceleration (higher 26.4, 95% CI: 24.6, 28.3; lower 24.6, 95% CI: 23.7, 25.7; p=0.080) and significantly higher rotational acceleration (higher 1020.2, 95% CI: 990.1, 1051.2; lower 946.6, 95% CI: 910.0, 984.8; p=0.003).

Conclusions Athletes with slower reaction time may be slower to prepare for collisions, resulting in higher magnitude head impacts. Clinicians should recognize athletes with slower reaction time on baseline neurocognitive assessments and understand the on-field implications. Research is needed to further identify a reaction time threshold between high and low performers, and risk of sustaining higher magnitude head impacts.

Competing interests None.