Purpose: The purpose of this study was to investigate the relationship between anthropometric measurements, proximal and distal lower extremity muscle performance, core muscle endurance, lower extremity flexibility, and neuromuscular control with the incidence of injury in recreational runners over one season. Also, when a relationship was established, we sought to evaluate the predictive validity for any of the variables being investigated for risk of injury in this population. Study Design: Prospective cohort Methods: Anthropometric measurements, proximal and distal isometric lower extremity muscle performance, isometric core muscle endurance, lower extremity flexibility and neuromuscular control were measured in 75 recreational runners prior to the start of a graded marathon training program. Incidence of injury was tracked over the course of 18 weeks, May 2014 – October 2014. Data was analyzed comparing the differences between injured and non-injured groups. Results: There were 33 repetitive stress injuries yielding a gross injury rate of 46% (male n=13, female n=20). Of all the variables analyzed, 5 variables emerged as possible a predictors including age, dominant limb rear foot posture, non dominant limb ankle DF ROM (extended), limb difference of Y balance scale composite scores and limb difference in the 6 M hop test. These variables were entered into a binary logistic regression analysis. Results of the regression indicated only the composite Y balance score difference variable as yielding a significant contribution (p = 0.01), with and predictive validity, (OR = 1.46, 95% CI =1.127 – 1.892). The model predicted 69.2% of the injuries with a specificity of 82% and sensitivity of 54.5%. A cutoff point of 3.6% was determined using a receiver operating characteristic curve. Runners were 3 times more likely to get injured with an asymmetry ≥ 3.6%. Conclusions: An asymmetry of lower extremity neuromuscular control ≥ 3.6% measured by the Y balance scale has been identified as a potential risk factor for injury in recreational runners. Clinical Relevance: This test can be performed as part of a pre-training screening or physical and may be helpful in identifying recreational runners at risk for injury.

This work of nonfiction examines the ways in which an unexpected and devastating health condition at the age of eighteen influences a person's identity and perception of self. The narrative is based largely around running, and the narrator explores what it means to live in a body that might fail.

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Encouraging running for exercise can be an important part of a comprehensive strategy for making communities more attractive for healthy physical activity. In order to make communities more runnerriendly, research must identify the features of the physical environment that are important for runners. This study identified these features through five focus groups of twenty-two runners. The focus group participants discussed the places they had run within the study community and described their positive and negative qualities. These discussions were then analyzed by examining direct quotations of the discussion transcripts and by noting the amount of participants concerned about particular issues. The findings showed that the participants chose their routes based on their ability to meet their exercise needs, safety, ease of access, and potential to be a fun experience. These insights into these runners’ preferences can be used to help make communities more conducive to physical activity.

Purpose: Reducing body temperature before exercise is called precooling. Past research suggests that reducing body core temperature (Tc) slightly can result in improved running performance. This study evaluated the effects that warming up, while wearing a cooling vest prior to an interval workout, had on Tc, and interval time in long-distance runners. Methods: Nineteen healthy male collegiate cross-country runners were recruited for this study. Each subject warmed up and exercised under two different conditions: (a) an experimental condition in which subjects wore a Nike PreCool® ice vest during warm-up and (b) a control condition. Subjects performed a warm-up followed by running eight 1000 m intervals separated by 90 s of rest. Heart rate (HR) and Tc were measured prior to warm-up, just prior to start of the first interval, and after each interval. Results: Tc measured directly prior to the first interval was significantly lower in the vest condition than the non-vest condition (difference = 0.37°C; P < 0.05). This difference persisted through the end of the sixth interval. Tc rose at a faster rate in the non-vest condition, though this difference was not significant (P = 0.07). Differences in HR and interval times were found to be nonsignificant between conditions for all intervals. Conclusion: Wearing an ice vest prior to and during warm-up effectively lowers Tc during long-distance interval training.

To measure the differences in ground reaction forces between running shoes, racing flats, and distance spikes, twenty intercollegiate distance runners ran across a force plate at 6.7m/s (for males) and 5.74m/s (for females) in each of the three types of shoes. In order to control for differences in foot strike, only subjects who had a heel strike were included in the data analysis (N=16). Repeated-measures ANOVA and Tukey's post-hoc test (p<0.05) revealed loading rate and impact peak to be significantly increased in the flats and spikes compared to running shoes. Stiffness in spikes was significantly higher than in running shoes. Stance time in spikes and flats was decreased. These results can be used to better inform competitive runners, coaches, and trainers of the risks and performance benefits when determining the frequency and duration of the use of competitive footwear in training.

Research surrounding the steeplechase is scarce, with most research focusing primarily on how biomechanical factors relate to maintaining running speed while crossing barriers. One area that has not been well explored is the relationship between biomechanical factors and hurdling economy. The purpose of this study was to investigate how performance times and biomechanical variables relate to hurdling economy during the steeplechase. This was accomplished by measuring running economy of collegiate and professional steeplechasers while running with and without hurdles. Biomechanical measures of approach velocity, take-off distance, clearance height, and lead knee extension while hurdling, as well as steeplechase performance times were correlated to a ratio of running economy with and without hurdles. Results indicated no correlation between steeplechase performance time and the ratio of running economy during the hurdle and non-hurdle laps. Results also indicated no correlation between the aforementioned biomechanical variables and ratio of running economy during the hurdle and non-hurdle laps. Increasing approach velocity did not negatively affect running economy. Steeplechasers may continue to increase approach velocity without hurting their economy or performance times.

Competition often requires teams that reside at sea level to compete against opponents whose residence is at a moderate altitude. This may pose a potential competitive disadvantage considering that moderate altitude may cause decrements in VO2max, distance covered, and time to exhaustion in endurance athletes. The purpose of this study was to examine the effect of altitude on game performance measures. Six NCAA Division I female soccer players (20.33 ± 1.21 y; 168 ± 6.45 cm; 62.5 ± 6.03 kg) were retrospectively examined. Comparisons were made between two competitions that were played at sea level (SL) within two weeks of a game played at a moderate altitude (1840 m) on game characteristics including high intensity running (HIR) and total distance covered (TDC). Analysis was performed on these six players who met a threshold of playing sixty or more minutes in each competition. A 10-Hz global positioning system (GPS) was used to measure distance and velocity. The rate of TDC and HIR during the game (m?min-1) and percentage of time at HIR during competition were evaluated. The two games at SL were averaged to establish baseline performance and the mean results were compared with the single game played at altitude. Paired samples t-tests were performed to determine if any mean differences existed between performance at altitude and sea level. Significant differences (p < 0.05) were seen in minutes played between the games at SL (74.23 ± 2.93 min) versus altitude (83.24 ± 5.27 min). The relative distance rate during the game at altitude was lower at altitude (105.77 ± 10.19 m?min-1) than at SL (120.55 ± 8.26 m?min-1). HIR rate was greater at SL (27.65 ± 9.25 m?min-1) compared to altitude (25.07 ± 7.66 m?min-1). The percent of time spent at high intensity was not significantly different (p = 0.064), yet tended to be greater at sea level (10.4 ± 3.3%) than when they performed at altitude (9.1 ±2.2%). Soccer performance at a moderate altitude appears to reduce the rate at which players run throughout the competition, as well as their rate at a high intensity. Results suggest that teams that reside at SL may be at a competitive disadvantage when competing at altitude.

We examine the problem of staffing refreshment stations at a long distance road race. A race is modeled as a mixed queueing network in which the required number of servers at each service station has to be estimated. Two models to represent the progress of runners along a long distance road race course are developed. One model is a single-class model that allows a road race manager to staff service stations assuming the runners are identical to those in some historical dataset. Another model is a multi-class simulation model that allows a road race manager to simulate a race of any number of runners, classified based on their running pace into different runner classes. Both the single-class model and the multi-class model include estimates for the rates at which the runners arrive at specified locations along the course. The arrival rates, combined with assumed service rates, allow us to base staffing decisions on the Erlang loss formula or a lesser known staffing rule that gives a lower bound for the required number of servers. We develop a staffing strategy that we call the Peak Arrival Staffing Bound (PASB), which is based on this staffing bound. The PASB and the Erlang loss formula are implemented in the single-class model and the multi-class simulation model. By way of numerical experiments, we find that the PASB is numerically stable and can be used to get staffing results regardless of the traffic intensity. This finding is in contrast to the Erlang loss formula, which is known to become numerically unstable and overflows when the traffic intensity exceeds 171. We compare numerical results of the PASB and the Erlang loss formula with a blocking probability level of 5% and find that when iii the traffic intensity is high, staffing results based on the PASB are more conservative than staffing results based on the Erlang loss formula. As the traffic intensity gets lower, we find that staffing results based on the PASB are similar to staffing results based on the Erlang loss formula. These findings suggest that the PASB can be a valuable tool to aid race directors in making staffing decisions for races of all traffic intensities

The purpose of this study was to compare the efficacy of two dose levels of L-Alanyl-LGlutamine in a commercially available sports drink to the sports drink only on time to exhaustion, neuromuscular fatigue and physiological measures during prolonged endurance exercise. Twelve endurance-trained males (23.5±3.7 yrs; 175.5±5.4 cm; 70.7±7.6 kg) performed four trials, each consisting of 1 hr treadmill runs at 75% of VO2peak followed by a run to exhaustion at 90% of VO2peak. The trials differed in type of hydration. One trial consisted of no hydration (NHY), another required ingestion of only a sports drink (ET), and two trials required ingestion of a low dose (LD) (300 mg∙500 ml-1) and high dose (HD) of L-Alanyl-L-Glutamine (1 g∙500 ml-1) mixed in the sports drink. During the fluid ingestion trials 250 ml were consumed every 15 min. Plasma glutamine, glucose, electrolytes, and osmolality were measured prior to the run (PRE), and at 30, 45, and 60 min. VO2, RQ, and HR were measured every 15 min and surface electromyography (EMG) of the vastus lateralis and rectus femoris were measured every 10 min during the 1 hr run. Time to exhaustion was significantly longer during the LD and HD trials compared with NHY. Plasma glutamine concentrations were significantly elevated at 45 min in LD and HD trials, and remained elevated at 60 min during HD. Sodium concentrations increased with the beginning of exercise and remained stable for the duration of the 1 hr run. At 60 min plasma sodium was significantly lower in all trials compared with NHY. The results from this study indicated that ingestion of the alanine-glutamine dipeptide at either the low or high dose significantly improved time to exhaustion during high intensity exercise compared to a no hydration trial. These differences were not noted between ET and NHY.