Age of first exposure to soccer heading and sensory reweighting for upright stance

Abstract

ObjectiveTo compare sensory reweighting for upright stance between soccer players who began soccer heading before age 10 years (AFE ≤ 10) and those who began soccer heading after age 10 years (AFE > 10).BackgroundIn 2015, US Soccer announced an initiative to eliminate soccer heading for youth players ages 10 years and younger and to limit soccer heading for children ages 11 to 13 years. Limited empirical evidence associates soccer heading during early adolescence and long-term behavioral deficits.Design/MethodsThirty college-aged soccer players self-reported AFE to soccer heading. Sensory reweighting was compared between AFE ≤ 10 [n = 19, 11 males (58%), 22 ± 3 years, 171 ± 9 cm, 70 ± 11 kg, 5 with concussion history (26%)] and AFE > 10 [N = 11, 5 males (45%), 22 ± 2 years, 172 ± 7 cm, 69 ± 13 kg, 3 with concussion history (27%)]. To evaluate sensory reweighting, we simultaneously perturbed upright stance with visual (i.e., moving visual scene at 0.2 Hz), vestibular (i.e., ±1 mA bilateral monopolar galvanic vestibular stimulus (GVS) at 0.36 Hz), and proprioceptive stimulation (i.e., 80 Hz vibratory stimulus to their bilateral Achilles tendons at 0.28 Hz). The visual stimulus was presented at different amplitudes (i.e., 0.2 m, 0.8 m in the anterior-posterior (AP) direction) to measure the leg-segment AP displacement change in gain to vision, an intramodal effect; and change in gain to GVS and vibration, both intermodal effects. A repeated-measures ANOVA was used to compare sensory reweighting between groups.ResultsThere were no differences in gain to vision (F1,28 = 0.033, p = 0.857, η2 = 0.001), gain to GVS (F1,28 = 0.001, p = 0.971, η2 = 0.000), or gain to vibration (F1,28 = 0.001, p = 0.974, η2 = 0.000), and no differences in sensory reweighting (i.e. conditionXgroup effect; vision, F3,84 = 0.160, p = 0.923, η2 = 0.006; GVS, F3,84 = 0.043, p = 0.988, η2 = 0.002; vibration, F1,28 = 0.068, p = 0.797, η2 = 0.002).ConclusionsThere were no differences in sensory processing for upright stance between AFE ≤ 10 and AFE > 10, suggesting that soccer heading during early adolescence is not associated with balance deficits in college-aged soccer players, notwithstanding potential deficits in other markers of neurological function.