A Visual Task's Impact On A Single Leg Jump Test

PURPOSE: To provide greater insight into factors that potentially impact readiness to return to play and injury prevention testing, this project aims to assess the impact of a neurocognitive load on the biomechanics of a jumping task. METHODS: Thirty recreational athletes performed 24 successful single leg crossover triple hop trials (12 for each leg) in the absence (12 trials) and presence (12 trials) of a neurocognitive load provided by a light training system. A 12-camera marker-less motion analysis system, sampling at 300 Hz recorded the trunk and lower limbs movements during the trials. The overall hop distance, hop 1 and 2 distances, hop 1 contact phase time, and hip and knee joint kinematics were obtained for each hopping trial. The trials were grouped according to gender, hop number and neurocognitive load condition and descriptive statistics obtained. Statistical Analysis Linear mixed models with fixed effects for gender, cognitive load, hop number and their interactions were tested for differences on the biomechanical outcomes at a significance level of p = 0.05. RESULTS: Significant main effects of gender (p < .001), cognitive load (p < .001), hop number (p < .001) and their three-way interaction (p = .028) on individual hop distances were noted. With respect to contact time, a significant effect of gender, load condition, hop number, and the two-way interactions between gender and load condition and load condition and hop number were noted (p < .006). A statistically significant effect of load condition (p < .001) on the maximum sagittal and frontal plane angle of the knee at maximum knee flexion was noted (Table). CONCLUSIONS: Cognitive loads appear to detrimentally affect athlete performance and knee biomechanics potentially placing them in at risk knee postures. Return to sport testing and rehabilitation programs should include cognitive loads to potentially improve program outcomes and reduce re-injury rates. - The mean (+/- 1 s.e.m) hop distance, contact time, and knee joint angle. Hop 1 Hop 2 Females Males Females Males No Load Load No Load Load No Load Load No Load Load Distance (m) 1.23 (+/- 0.05) 1.17 (+/- 0.05) 1.70 (+/- 0.05) 1.63 (+/- 0.05) 1.35 (+/- 0.05) 1.28 (+/- 0.05) 1.91 (+/- 0.05) 1.75 (+/- 0.05) Contact Time (s) 0.308 (+/- 0.004) 0.353 (+/- 0.006) 0.332 (+/- 0.004) 0.349 (+/- 0.005) 0.318 (+/- 0.004) 0.306 (+/- 0.004) 0.326 (+/- 0.004) 0.303 (+/- 0.004) Knee Joint Flexion (deg) 30 (+/- 2.6) 21 (+/- 2.6) 36 (+/- 3.1) 28 (+/- 23.1) - - - - Knee Joint Valgus (deg) 5 (+/- 0.8) 4 (+/- 0.8) 3 (+/- 0.9) 2 (+/- 0.9) - - - -