Neurocognitive differences may be associated with the loss of neuromuscular control and coordination errors, predisposing certain intercollegiate athletes to noncontact anterior cruciate ligament injuries.

The purpose of this study was to determine the longitudinal effects of weighted sled (WS) and weighted vest (WV) sprint training on maximum velocity sprint performance and kinematics. Twenty male collegiate lacrosse players were randomly assigned to a WS group (n = 7) towing 10% body mass, a WV group (n = 6) loaded with 18.5% body mass, or an unresisted (UR) active control group (n = 7). All subjects completed 13 training sessions over 7 weeks. Pre- and post-test measures of sprint time and average velocity across the distance interval of 18.3 to 54.9 m were used to assess sprint performance, whereas high-speed video (300 Hz) and motion-analysis software were used to analyze stride length, stride rate, ground contact time, and flight time. A 3 × 2 repeated measures analysis of variance was performed for each dependent variable and revealed no significant between-group differences for any of the sprint performance or kinematic stride cycle measures. Effect size statistics suggested small improvements in 18.3- to 54.9-m sprint time and average velocity for the UR group but only trivial improvements for the WS and WV groups. With regard to sprint performance, the results indicate that WS and WV training had no beneficial effect compared with UR training. In fact, for the loads used by WS and WV in this study, UR training may actually be superior for improving sprint performance in the 18.3- to 54.9-m interval.

Context: Athletes are at an inherent risk for sustaining concussions. Research examining the long-term consequences of sport-related concussion has been inconsistent in demonstrating lingering neurocognitive decrements that may be associated with a previous history of concussion.Objective: To determine the relationship between concussion history and postconcussion neurocognitive performance and symptoms in collegiate athletes.Design: Repeated-measures design. Setting: Multi-center analysis of collegiate athletes.Patients or Other Participants: Fifty-seven concussed collegiate athletes (36 without concussion history, 21 with a history of 2 or more concussions).Intervention(s): All subjects were administered an Immediate Post-Concussion Assessment and Cognitive Testing (Im-PACT) neurocognitive test battery, which measures verbal memory, visual memory, reaction time, and visual processing speed and 22 concussion symptoms.Main Outcome Measure(s): Subjects who sustained a concussion were administered 2 follow-up tests at days 1 and 5 postinjury. Independent variables were history of concussion (no history of concussion, 2 or more concussions) and time (baseline, day 1 postconcussion, or day 5 postconcussion).Results: A within-subjects effect (time) on ImPACT performance (P , .001), a between-subjects multivariate effect of group (P , .001), and a group-by-time interaction (P 5 .034) were noted. Athletes with a concussion history performed significantly worse on verbal memory (P 5 .01) and reaction time (P 5 .023) at day 5 postconcussion compared with athletes who did not report a previous concussion. No significant group differences were seen at day 5 postinjury on visual memory (P 5 .167), processing speed (P 5 .179), or total concussion symptoms (P 5 .87).Conclusions: Concussed collegiate athletes with a history of 2 or more concussions took longer to recover verbal memory and reaction time than athletes without a history of concussion.Key Words: mild traumatic brain injury, ImPACT, memory, reaction time Key PointsN Compared with collegiate athletes having no history of concussion, those with a history of concussion took longer to recover after concussion on neurocognitive measures of verbal memory and reaction time.N After concussion, collegiate athletes with a history of concussion were impaired in verbal memory and reaction time, demonstrating at least 1 reliable decline in each measure, at day 5 compared with baseline.

This investigation analyzed the sprint velocity profiles for athletes who completed the 40-yard (36.6m) dash at the 2016 NFL Combine. The purpose was to evaluate the relationship between maximum velocity and sprint performance, and to compare acceleration patterns for fast and slow athletes. Using freely available online sources, data were collected for body mass and sprint performance (36.6m time with split intervals at 9.1 and 18.3m). For each athlete, split times were utilized to generate modeled curves of distance vs. time, velocity vs. time, and velocity vs. distance using a mono-exponential equation. Model parameters were used to quantify acceleration patterns as the ratio of maximum velocity to maximum acceleration (vmax / amax, or τ). Linear regression was used to evaluate the relationship between maximum velocity and sprint performance for the entire sample. Additionally, athletes were categorized into fast and slow groups based on maximum velocity, with independent t-tests and effect size statistics used to evaluate between-group differences in sprint performance and acceleration patterns. Results indicated that maximum velocity was strongly correlated with sprint performance across 9.1m, 18.3m, and 36.6m (r of 0.72, 0.83, and 0.94, respectively). However, both fast and slow groups accelerated in a similar pattern relative to maximum velocity (τ = 0.768 ± 0.068s for the fast group and τ = 0.773 ± 0.070s for the slow group). We conclude that maximum velocity is of critical importance to 36.6m time, and inclusion of more maximum velocity training may be warranted for athletes preparing for the NFL Combine.