Analysis of elite road-cycling sprints in relation to maximal power-velocity-endurance profile: a longitudinal one-case study.

The aims of the present study were to characterize the mechanical output of final road sprints of an elite sprinter during international competitions in relation to his power-velocity-endurance characteristics and to investigate the relationship between this sprint performance and the power produced during preceding phases of the race. The sprinter performed a set of short and long sprints (5 to 15-s) on a cycle ergometer to determine his maximal power-velocity-endurance profile. Based on eleven races, the distribution of power throughout each race, peak and mean power (Ppeak and Pmean ) and associated pedaling rates (vPpeak and vPmean ) during the final sprint were analyzed. The power-velocity-endurance profile of the sprinter indicated that his theoeretical mean maximal power and corresponding optimal pedaling rate ranged from 20.0 W.kg-1 (124 rpm) for a 1-s sprint to 15.0 W.kg-1 (109 rpm) for 20 s. Race data showed that final road sprints were mainly performed on the ascending limb of the power-velocity relationship (vPpeak , 104 ± 8 and vPmean , 101 ± 8 rpm). Additionally, Ppeak and Pmean were lower than the theoretical maximal power determined from the power-velocity-endurance profile (9.9 ± 7.0% and 10.6 ± 9.8%, respectively), which highlighted a significant state of fatigue induced by the race. Finally, sprint power exhibited a high variability between races and was strongly related to the level of power produced during the last minute before the sprint. These findings show the importance of considering both the power-velocity-endurance qualities and the power demand of the last lead-up phase before the sprint in order to optimize final sprint performance.

Exertional heat illness incidence and on-site medical team preparedness in warm weather.

To investigate the influence of estimated wet bulb globe temperature (WBGT) and the International Institute of Race Medicine (IIRM) activity modification guidelines on the incidence of exertional heat stroke (EHS) and heat exhaustion (HEx) and the ability of an on-site medical team to treat those afflicted. Medical records of EHS and HEx patients over a 17-year period from the New Balance Falmouth Road Race were examined. Climatologic data from nearby weather stations were obtained to calculate WBGT with the Australian Bureau of Meteorology (WBGTA) and Liljegren (WBGTL) models. Incidence rate (IR) of EHS, HEx, and combined total of EHS and HEx (COM) were calculated, and linear regression analyses were performed to assess the relationship between IR and WBGTA or WBGTL. One-way ANOVA was performed to compare differences in EHS, HEx, and COM incidence to four alert levels in the IIRM guidelines. Incidence of EHS, HEx, and COM was 2.12, 0.98, and 3.10 cases per 1000 finishers. WBGTA explained 48, 4, and 46% of the variance in EHS, HEx, and COM IR; WBGTL explained 63, 13, and 69% of the variance in EHS, HEx, and COM IR. Main effect of WBGTA and WBGTL on the alert levels were observed in EHS and COM IR (p < 0.05). The cumulative number of EHS patients treated did not exceed the number of cold water immersion tubs available to treat them. EHS IR increased as WBGT and IIRM alert level increased, indicating the need for appropriate risk mitigation strategies and on-site medical treatment.

Performance and age of African and non-African runners in World Marathon Majors races 2000-2014.

The age for the fastest marathoners is well investigated, but not the age and nationality of the fastest. We investigated the age of peak marathon performance for the annual top 100 women and men competing in four races of the "World Marathon Majors" (Boston, Berlin, Chicago and New York) and the "Stockholm Marathon" between 2000 and 2014 using mixed-effects regression analyses and one-way ANOVA. Race times of Ethiopian men decreased to 2:14 h:min, but remained unchanged for Kenyan (2:14 h:min), Moroccan (2:15 h:min) and South African (2:18 h:min) men. Race times in Ethiopian (2:34 h:min), Kenyan (2:29 h:min) and South African (2:49 h:min) women showed no changes. Age increased in Ethiopian and South African men to 29.0 ± 5.0 and 32.0 ± 1.0 years, respectively. Age for Kenyan (29.9 ± 2.0 years) and Moroccan (34.9 ± 3.9 years) men remained unchanged. Age remained unchanged for Ethiopian (26.5 ± 2.0 years), Kenyan (30.0 ± 0.8 years) and South African (36.3 ± 7.0 years) women. In summary, Ethiopian men improved marathon race times, but not Ethiopian women. Age increased in Ethiopian men, but not in Ethiopian women. For practical applications, female and male marathoners from Ethiopia were the youngest and the fastest.

Knowledge and Belief Toward Heat Safety and Hydration Strategies Among Runners: A Preliminary Evaluation.

CONTEXT: Little is known about how educating runners may correct common misconceptions surrounding heat safety and hydration strategies. OBJECTIVE: To investigate (1) beliefs and knowledge about heat safety and hydration strategies among recreational runners and (2) the effectiveness of an educational video in optimizing performance in the heat. DESIGN: Cross-sectional study. SETTING: Survey. PATIENTS OR OTHER PARTICIPANTS: A total of 2091 (25.1%) of 8319 runners registered for the 2017 Falmouth Road Race completed at least 1 of the 3 administered surveys. INTERVENTION(S): A 5.3-minute video and an 11-question survey regarding heat safety and hydration strategies were developed, validated, and implemented. The survey was e-mailed to registrants 9 weeks before the race (PRERACE), after they viewed the video (POSTEDU), and the afternoon of the race (POSTRACE). MAIN OUTCOME MEASURE(S): The total score for responses to 2 multiple choice questions and nine 5-point (response range = strongly agree to strongly disagree) Likert-scale questions. RESULTS: The PRERACE results showed that more than 90% of respondents recognized the importance of staying hydrated beginning the day before the planned activity, correctly identified that dark color urine is not a sign of euhydration, and believed that dehydration may increase the risk for heat syncope. Conversely, fewer than 50% of respondents knew the number of days required to achieve heat acclimatization, the role of sweat-rate calculation in optimizing one's hydration strategy, or the risk of water intoxication from drinking too much water. An improvement in survey score from PRERACE to POSTEDU was observed (mean difference = 2.00; 95% confidence interval = 1.68, 2.33; P < .001) among runners who watched the video, and 73% of the improvement in their scores was retained from POSTEDU to POSTRACE (mean difference = -0.54; 95% confidence interval = -0.86, -0.21; P < .001). CONCLUSIONS: The video successfully shifted runners' beliefs and knowledge to enable them to better optimize their performance in the heat.

Influence of Race Performance and Environmental Conditions on Exertional Heat Stroke Prevalence Among Runners Participating in a Warm Weather Road Race.

The New Balance Falmouth Road Race held in Falmouth, Massachusetts, U.S. is a short distance race (11.26 km) that is well-known for high rates of exertional heat stroke (EHS). Previous research has documented the increased EHS rates with hotter and more humid weather conditions, yet did not explore the influence of race pacing on EHS risk. In this study, we leverage 15 years of data to investigate if runners who experienced an EHS moderate their average paces based on weather conditions and if there is a difference in average race pace between participants who experienced an EHS and other runners. Results indicate that runners who experience an EHS do not appear to reduce their average pace with increasing WBGT warning flag categories. In addition, runners who suffer an EHS run at a faster average pace than others, even when controlling for age, gender, race performance, and starting time WBGT. This suggests the important role of metabolic heat production as a risk factor of EHS. Since race pacing is a modifiable risk factor, our findings support the need for race organizers to actively encourage runners to adjust race pacing based on weather conditions.

On-site treatment of exertional heat stroke.

BACKGROUND: Exertional heat stroke is a devastating condition that can cause significant morbidity and mortality. Rapid cooling is the most effective means of treating heat stroke, but little is published on the safety and logistics of cooling patients on site at a major sporting event. PURPOSE: To describe an on-site exertional heat stroke treatment protocol and to compare the outcomes of patients treated on site to those transferred to hospitals. STUDY DESIGN: Descriptive epidemiological study. METHODS: Using race-day medical records and ambulance run sheets, patients who developed exertional heat stroke at the Indianapolis half-marathon from 2005 to 2012 were identified. Exertional heat stroke was defined as runners with a core temperature measured with a rectal thermometer greater than 102° F and altered mental status. Clinical information and patient outcomes were abstracted from the race medical tent and hospital charts by 3 separate trained reviewers using structured methods and a data collection form. Two reviewers, using a RedCAP database and dual-data entry, abstracted records for each patient. A third arbitrated all discrepancies between reviewers. Clinical signs, treatments, and outcomes were calculated using descriptive statistics, and data were grouped and compared for patients treated on site or transferred to local hospitals for treatment. RESULTS: Over 235,000 athletes participated in the event over the 8-year period, with 696 seeking medical care. A total of 32 heat stroke victims were identified during the study period; of these, 22 were treated on site. Of these, 68% were treated with cold-water immersion and 59% were discharged home from the race. Ten exertional heat stroke patients were transported from the race course to local hospitals. None of them underwent cold-water immersion, and 40% of them were subsequently discharged home. No patients in the study died. CONCLUSION: On-site treatment of athletes who develop exertional heat stroke appears to be both safe and effective. On-site treatment may decrease the local burden of critically ill patients to emergency departments during large athletic events.

Dietary supplement usage and motivation in Brazilian road runners.

BACKGROUND: The consumption of dietary supplements is highest among athletes and it can represent potential a health risk for consumers. OBJECTIVE: The aim of this study was to determine the prevalence of consumption of dietary supplements by road runners. METHODS: We interviewed 817 volunteers from four road races in the Brazilian running calendar. The sample consisted of 671 male and 146 female runners with a mean age of 37.9 ± 12.4 years. RESULTS: Of the sample, 28.33% reported having used some type of dietary supplement. The main motivation for this consumption is to increase in stamina and improve performance. The probability of consuming dietary supplements increased 4.67 times when the runners were guided by coaches. The consumption of supplements was strongly correlated (r = 0.97) with weekly running distance, and also highly correlated (r = 0.86) with the number of years the sport had been practiced. The longer the runner had practiced the sport, the higher the training volume and the greater the intake of supplements. The five most frequently cited reasons for consumption were: energy enhancement (29.5%), performance improvement (17.1%), increased level of endurance (10.3%), nutrient replacement (11.1%), and avoidance of fatigue (10.3%). About 30% of the consumers declared more than one reason for taking dietary supplements. The most consumed supplements were: carbohydrates (52.17%), vitamins (28.70%), and proteins (13.48%). CONCLUSIONS: Supplement consumption by road runners in Brazil appeared to be guided by the energy boosting properties of the supplement, the influence of coaches, and the experience of the user. The amount of supplement intake seemed to be lower among road runners than for athletes of other sports. We recommend that coaches and nutritionists emphasise that a balanced diet can meet the needs of physically active people.

Performance and age of African and non-African runners in half- and full marathons held in Switzerland, 2000-2010.

BACKGROUND: Endurance running performance of African (AF) and non-African (NAF) athletes is investigated, with better performances seen for Africans. To date, no study has compared the age of peak performance between AF and NAF runners. The present research is an analysis of the age and running performance of top AF and NAF athletes, using the hypothesis that AF athletes were younger and faster than NAF athletes. METHODS: Age and performance of male and female AF and NAF athletes in half-marathons and marathons held in Switzerland in 2000-2010 were investigated using single and multilevel hierarchical regression analyses. RESULTS: For half-marathons, male NAF runners were older than male AF runners (P = 0.02; NAF, 31.1 years ± 6.4 years versus AF, 26.2 years ± 4.9 years), and their running time was longer (P = 0.02; NAF, 65.3 minutes ± 1.7 minutes versus AF, 64.1 minutes ± 0.9 minutes). In marathons, differences between NAF and AF male runners in age (NAF, 33.0 years ± 4.8 years versus AF, 28.6 years ± 3.8 years; P < 0.01) and running time (NAF, 139.5 minutes ± 5.6 minutes versus AF, 133.3 minutes ± 2.7 minutes; P < 0.01) were more pronounced. There was no difference in age (NAF, 31.0 years ± 7.0 years versus AF, 26.7 years ± 6.0 years; P > 0.05) or running time (NAF, 75.0 minutes ± 3.7 minutes versus AF, 75.6 minutes ± 5.3 minutes; P > 0.05) between NAF and AF female half-marathoners. For marathoners, NAF women were older than AF female runners (P = 0.03; NAF, 31.6 years ± 4.8 years versus AF, 27.8 years ± 5.3 years), but their running times were similar (NAF, 162.4 minutes ± 7.2 minutes versus AF, 163.0 minutes ± 7.0 minutes; P > 0.05). CONCLUSION: In Switzerland, the best AF male half-marathoners and marathoners were younger and faster than the NAF counterpart runners. In contrast to the results seen in men, AF and NAF female runners had similar performances. Future studies need to investigate performance and age of AF and NAF marathoners in the World Marathon Majors Series.