Road Race Research Articles

Recommended water immersion duration for the field treatment of exertional heat stroke when rectal temperature is unavailable.

The recommended treatment for exertional heat stroke is immediate, whole-body immersion in < 10 °C water until rectal temperature (Tre) reaches ≤ 38.6°C. However, real-time Tre assessment is not always feasible or available in field settings or emergency situations. We defined and validated immersion durations for water temperatures of 2-26°C for treating exertional heat stroke. We compiled data for 54 men and 18 women from 7 previous laboratory studies and derived immersion durations for reaching 38.6°C Tre. The resulting immersion durations were validated against the durations of cold-water immersion used to treat 162 (98 men; 64 women) exertional heat stroke cases at the Falmouth Road Race between 1984 and 2011. Age, height, weight, body surface area, body fat, fat mass, lean body mass, and peak oxygen uptake were weakly associated with the cooling time to a safe Tre of 38.6°C during immersions to 2-26°C water (R2 range: 0.00-0.16). Using a specificity criterion of 0.9, receiver operating characteristics curve analysis showed that exertional heat stroke patients must be immersed for 11-12min when water temperature is ≤ 9°C, and for 18-19min when water temperature is 10-26°C (Cohen's Kappa: 0.32-0.75, p < 0.001; diagnostic odds ratio: 8.63-103.27). The reported immersion durations are effective for > 90% of exertional heat stroke patients with pre-immersion Tre of 39.5-42.8°C. When available, real-time Tre monitoring is the standard of care to accurately diagnose and treat exertional heat stroke, avoiding adverse health outcomes associated with under- or over-cooling, and for implementing cool-first transport second exertional heat stroke policies.

Importance of training volume during intensified training in elite cyclists: Maintained vs. reduced volume at moderate intensity.

Male elite cyclists (average VO2 -max: 71 mL/min/kg, n = 18) completed 7 weeks of high-intensity interval training (HIT) (3×/week; 4-min and 30-s intervals) during the competitive part of the season. The influence of a maintained or lowered total training volume combined with HIT was evaluated in a two-group design. Weekly moderate-intensity training was lowered by ~33% (~5 h) (LOW, n = 8) or maintained at normal volume (NOR, n = 10). Endurance performance and fatigue resistance were evaluated via 400 kcal time-trials (~20 min) commenced either with or without prior completion of a 120-min preload (including repeated 20-s sprints to simulate physiologic demands during road races). Time-trial performance without preload was improved after the intervention (p = 0.006) with a 3% increase in LOW (p = 0.04) and a 2% increase in NOR (p = 0.07). Preloaded time-trial was not significantly improved (p = 0.19). In the preload, average power during repeated sprinting increased by 6% in LOW (p < 0.01) and fatigue resistance in sprinting (start vs end of preload) was improved (p < 0.05) in both groups. Blood lactate during the preload was lowered (p < 0.001) solely in NOR. Measures of oxidative enzyme activity remained unchanged, whereas the glycolytic enzyme PFK increased by 22% for LOW (p = 0.02). The present study demonstrates that elite cyclists can benefit from intensified training during the competitive season both with maintained and lowered training volume at moderate intensity. In addition to benchmarking the effects of such training in ecological elite settings, the results also indicate how some performance and physiological parameters may interact with training volume.

Racing bicycle tyres: experimental indoor evaluation of relaxation length

The paper presents the measurement of the relaxation length of road racing bicycle tyres. In the paper the relaxation length is given as the ratio between cornering stiffness and lateral stiffness of the tyre. Tests were performed with VeTyT, a test-rig specifically designed for measuring the lateral characteristics of bicycle tyres. The results from road racing bicycle tyres of two different brands are discussed. Then, a comparison is presented between of 26 mm and 28 mm wide racing tyres. The tyres were tested both on a flat track and on a drum of 2.6 m diameter. The relaxation length for tests on flat track resulted to be on average 15% higher than the ones on drum, for the same vertical load and inflation pressure. In addition, the large role played by inflation pressure on the relaxation length was discovered. Since the relaxation length may affect the bicycle dynamics, the study provides the first quantitative information for the further development of safer and more performant bicycles.

International Road Race of São Silvestre: why don't brazilians win anymore and what do we need to do?

Aim: To compare the Brazilian and foreign runners in the International Road Race of São Silvestre. Methods: Retrospective study that evaluated the results of 220 athletes of both genders that reached the top 10. The time of each race was converted in seconds to compare the performance. Results: After 11 editions of the International Road Race of São Silvestre only one Brazilian athlete won without any female victory. In the male 10 foreign athletes won (Kenya 5 x 5 Ethiopia) and all the females proved were won by foreign athletes (Kenya 9 x 2 Ethiopia). There was a difference when comparing the performance of foreign elite runners in the male (p&lt;0.004) and female (p&lt;0.001). Conclusion: Despite the large number of existing runners, the Brazilian elite does not develop the same level of performance to beat African athletes. To change this condition, it is necessary to change the strategy for preparing Brazilian athletes from the base of training athletes.

DATA COLLECTION AND PERFORMANCE EVALUATION OF RUNNING TRAINING SPORT USING DIFFERENT NEURAL NETWORK TECHNIQUES

With the increasing engagement of human beings in the pursuit of healthcare, running as a sport has become a fashionable and healthcare first choice. This research uses artificial intelligence technology to carry out intelligent analysis when conducting running training. Artificial intelligence technology can accurately analyze and predict the application requirements of sports training postures. We proposed an analysis of sports posture and a prediction system, which uses running training data in the form of a heart rate, recorded on a GPS smart sports watch, as well as using the recurrent neural network (RNN), long and short-term memory (LSTM) and the gate recursive unit (GRU). These three types of neural network methods can predict which method is best suited for a road race and can confirm that it will be completed within the scheduled finish time; these models will also perform an intelligent analysis of physical fitness (heart rate, pace) and running technology (cadence, pace). The training and test data are collected from the running training records (running distance, time, heart rate, stride frequency, stride length, pace, calories, altitude and other characteristic values) as input parameters, to test and compare the running completion time trends of the RNN, LSTM and GRU neural network methods in the exercise table, so as to evaluate their predictive abilities. The results show that the GRU method has the best predictive accuracy, and the least accurate is the LSTM method. After the hidden layers are added to the three predictive methods, the RNN is slightly regressive, the LSTM indicates a trend of significant improvement and the GRU exhibits less obvious changes.

Racing bicycle tyres – Influence on mechanical characteristics of internal pressure, vertical force, speed and temperature

The paper describes how internal pressure, vertical force, speed and rolling surface temperature may affect the mechanical characteristics of a road racing bicycle tyre. The results were obtained from an experimental test campaign performed with VeTyT, a test-rig specifically designed for measuring the mechanical characteristics of bicycle tyres.The static deflection of tyre for different inflation pressures and vertical loads was measured to determine the static tyre vertical stiffness. Results for tyre rolling on flat track or on a drum were compared. Dynamic analyses were focused on evaluating the effect of inflation pressure and vertical load, for two rims featured by different lateral stiffness. Then, the respective effects of speed and of temperature of the rolling surface on the lateral force were considered.Stiffer rims can ensure higher values of cornering stiffness. In addition, higher inflation pressure is recommended only for heavy vertical loads. For low vertical loads, too inflated tyre results to be less performant, i.e. to show lower values of cornering stiffness. The speed can affect the mechanical characteristics of bicycle tyres mainly for slip angles less than 1.5°, while the temperature of the rolling surface is the most affecting parameter for slip angles larger than 3°.

Thermoregulatory responses during road races in hot-humid conditions at the 2019 Athletics World Championships.

The purpose of this study was to characterize thermoregulatory and performance responses of elite road-race athletes, while competing in hot, humid, night-time conditions during the 2019 IAAF World Athletic Championships. Male and female athletes, competing in the 20 km racewalk (n = 20 males, 24 females), 50 km racewalk (n = 19 males, 8 females), and marathon (n = 15 males, 22 females) participated. Exposed mean skin (Tsk) and continuous core body (Tc) temperature were recorded with infrared thermography and ingestible telemetry pill, respectively. The range of ambient conditions (recorded roadside) was 29.3°C-32.7°C air temperature, 46%-81% relative humidity, 0.1-1.7 m·s-1 air velocity, and 23.5°C-30.6°C wet bulb globe temperature. Tc increased by 1.5 ± 0.1°C but mean Tsk decreased by 1.5 ± 0.4°C over the duration of the races. Tsk and Tc changed most rapidly at the start of the races and then plateaued, with Tc showing a rapid increase again at the end, in a pattern mirroring pacing. Performance times were between 3% and 20% (mean = 113 ± 6%) longer during the championships compared with the personal best (PB) of athletes. Overall mean performance relative to PB was correlated with the wet-bulb globe temperature (WBGT) of each race (R2 = 0.89), but not with thermophysiological variables (R2 ≤ 0.3). As previously reported in exercise heat stress, in this field study Tc rose with exercise duration, whereas Tsk showed a decline. The latter contradicts the commonly recorded rise and plateau in laboratory studies at similar ambient temperatures but without realistic air movement.NEW & NOTEWORTHY This paper provides a kinetic observation of both core and skin temperatures in 108 elite athletes, during various outdoor competition events, adding to the very limited data so far available in the literature taken during elite competitions. The field skin temperature findings contrast previous laboratory findings, likely due to differences in relative air velocity and its impact on the evaporation of sweat. The rapid rise in skin temperature following cessation of exercise highlights the importance of infrared thermography measurements being taken during motion, not during breaks, when being used as a measurement of skin temperature during exercise.

Research on Optimal Riding Strategy Based on Improved Rider Power Position Analysis Model

How to achieve good results in bicycle road races is a question worth pondering on. we developed a rider power-position analysis model that can be applied to any type of rider to determine the relationship between that rider's position and power on the track. This paper considered extending the model to team time trials. The team maintains a stable pace, maintains different power in different positions, the entire team maintains a distance of 30cm, and the strong and weak are arranged alternately.

Aerodynamic impact of cycling postures on drafting in single paceline configurations

This paper presents finite-volume-based scale-adaptive simulations of single paceline configurations up to eight cyclists for three different postures. In cycling, drag reduction by drafting in pacelines is a key strategy to limit energy expenditure. The drag reductions of individual cyclists and of the paceline as a whole are determined by several factors, including cycling posture. To the best of our knowledge, a systematic study on the effect of cyclist posture on the drag in single pacelines has not yet been published in the scientific literature. In this study, drag reduction and flow field data were computed while validation was performed by wind tunnel measurements. The three investigated postures concern a road race dropped posture with either a large or small sagittal torso angle and a time trial posture. For the considered pacelines in which all cyclists have the same posture, the drag of a cyclist could be reduced by changing either the posture, or the position, or both. Changing posture can yield a maximum drag reduction of about 15% for the leading cyclist. The position in the paceline with minimum drag was the one but last, independent of the investigated cycling postures. For the pacelines containing eight cyclists, maximum drag reductions up to 63% were found. The largest drag reduction was 68%, obtained by riding in penultimate position in an eight cyclist paceline in dropped position with a small sagittal torso angle.

Road Racing Event Management Satisfaction: A Scoping Review of the Literature in Different Populations

The main purpose of this scoping literature review is to map empirical research concerning the satisfaction of road race participants, as well as what leads to their return and how events should be promoted and managed. The search was made on EBSCO, Academic Search Complete, Business Source Complete, Web of Science online database for studies between 2000 and 2020 using the following as keywords: “road race”, “marathon”, “running event”, “running”, “satisfaction”, “event loyalty”, “consumer behaviour”, “marketing”, and “communication”. After applying the inclusion criteria, 32 studies were selected. The descriptive analysis showed that satisfaction with the event depends on the quality of service provided, the image of the event, satisfaction with personal performance, perceived economic value, and disconfirmation of expectation, while the intention to revisit is largely affected by satisfaction with the event in different populations. In addition, various market segmentations are obtained according to the age and the gender, as well as important management and marketing information. The conclusions of this review can contribute to a better management and organization of road racing events around the world.

Effect of Gear Ratio and Cadence on Gross Efficiency and Pedal Force Effectiveness during Multistage Graded Cycling Test Using a Road Racing Bicycle.

Gross efficiency (GE) and the index of pedal force effectiveness (IFE) are important factors that enhance cyclists' performance; however, the effects of changing pedal force (gear ratio) and cadence on these indices while riding on a road racing bicycle are poorly investigated. This study aimed to examine the effect of changing gear ratio or cadence on GE and IFE using a road racing bicycle. Nine male cyclists completed graded submaximal cycling tests (five stages of 4 min submaximal cycling sessions with 1 min passive rest intervals). The work rate of each stage was determined using two principles: changing gear ratio at a fixed cadence and changing cadence at a fixed gear ratio. We determined GE and IFE using respiratory variables and pedal reaction forces, respectively. Increasing the gear ratio improved GE, and was associated with the IFE. Although increasing the cadence slightly improved GE from the initial level, the increased values then mostly maintained. IFE was almost stable even when cadence increased. Moreover, no significant correlation was observed between the changes in GE and IFE accompanied by increasing cadence. Our data indicate that an increasing gear ratio, but not cadence, may affect GE and IFE while riding on a road racing bicycle.

Interchangeability between the Data Obtained by Two Powermeters during Road Cycling Competitions: A Case Study

Various power meters are used to assess road-cycling performance in training and competition, but no previous study has analyzed their interchangeability in these conditions. Therefore, the purpose was to compare the data obtained from two different power meters (PowerTap vs. Power2Max) during cycling road races. A national-level under-23 male competitive cyclist completed six road-cycling official competitions (five road races and one individual time trial), in which power output was simultaneously registered with the two power meters. After this, the main power output variables were analyzed with the same software. The average and critical power obtained from the PowerTap power meter were slightly lower than from the Power2Max power meter (3.56 ± 0.68 and 3.62 ± 0.74 W·kg-1, 5.06 and 5.11 W·kg-1, respectively), and the correlations between both devices were very high (r ≥ 0.996 and p < 0.001). In contrast, the PowerTap power meter registered a significantly higher (p < 0.05) percentage of time at <0.75 and >7.50 W·kg-1 and power profile at 1, 5 and 10 s. In conclusion, the data obtained in competitions by the two power meters were interchangeable. Nevertheless, the Power2Max power meter underestimated the pedaling power during short and high-intensity intervals (≤10.0 s and >7.50 W·kg-1) compared to the PowerTap power meter. Therefore, the analysis of these efforts should be treated with caution.

Impact of advanced footwear technology on elite men’s in the evolution of road race performance

ABSTRACT Advanced footwear technology (AFT) changed footwear design concepts by using a curved carbon fibre plate in combination with new, more compliant and resilient foams. The aim of this study was (1) to examine the individual effects of AFT on the evolution of the main road events and (2) to re-assess the impact of AFT on the world’s top-100 performance in men’s 10k, half-marathon and marathon events. Data from the top-100 men’s 10k, half-marathon and marathon performances were collected between 2015 and 2019. The shoes used by the athletes were identified in 93.1% of the cases by publicly available photographs. Runners wearing AFT had an average performance of 1671 ± 22.28 s compared to 1685 ± 18.97 s of runners not using AFT in 10k (0.83%) (p < 0.001), 3589 ± 29.79 s compared to 3607 ± 30.49 s in half-marathon (0.50%) (p < 0.001) and 7563 ± 86.10 s compared to 7637 ± 72.51 s in the marathon (0.97%) (p < 0.001). Runners wearing AFTs were faster by ~1% in the main road events compared to non-users. Individual analysis showed that ~25% of the runners did not benefit from the use of this type of footwear. The results of this study suggest that AFT has a clear positive impact on running performance in main road events.

Study on Cycling Events Around the Lake

The socio-economic value of holding a road cycling race around the lake in Bengbu Longzi Lake and its surrounding scenic areas is analyzed through theoretical research on the significance of the race, brand image, means of communication, route planning, and other aspects. The commercial and social value of holding the Tour de Lake for the Bengbu area is studied. Setting up the Tour de Lake will not only help to promote local visibility and the development of the leisure tourism industry but will also help to guide and promote the participation of the student population in the university city area of Longzi Lake in cycling.

Special training of highway cyclists considering energy metabolism types

The competitive activity of racers on the highway makes high demands on the level of their physical fitness, since the competition can be held in the form of a multi-day race. The training of road racers is based on the development of physical qualities, among which the most important for them are different types of endurance. The development of these qualities is possible only with a purposeful impact on their physiological systems and, in particular, on the mechanisms of energy supply of muscle activity.&#x0D; The analysis of the literature showed that in most of the works devoted to the preparation of racers on the highway, there is no necessary scientific information characterizing the features of the energy supply of their muscular activity during preparation for multi-day races. This greatly limits the possibilities for differentiating the means and methods of developing different types of endurance in the process of training. The issues of application of methods for the development of endurance among racers on the highway, where the differentiation criterion would be different types of energy metabolism, are also insufficiently developed. The existing system of preparation of racers on the highway for competitions is characterized by insufficient consideration of the peculiarities of the mechanism of energy supply of muscular activity in the training process. Its main drawback is its general approach to training road riders. Coaches in their work with athletes are guided solely by their personal experience of preparing road riders for competitions.

Continuous Thermoregulatory Responses to a Mass-Participation 89-km Ultramarathon Road Race.

To continuously measure body core temperature (Tc) throughout a mass-participation ultramarathon in subelite recreational runners to quantify Tc magnitude and the influence of aerobic fitness and body fat. Twenty-three participants (19 men and 4 women; age 45 [9]y; body mass 72.0 [9.3]kg; body fat 26% [6%]; peak oxygen uptake 50 [6]mL·kg-1·min-1) had gastrointestinal temperature measured during an 89-km ultramarathon. Prerace-to-postrace changes in body mass, plasma sodium, and fluid and food recall quantified body water balance. In maximal environmental conditions of 26.3 °C and 53% humidity, 21 of the 23 participants finished in 10:28 (01:10)h:min while replacing 49% (27%) of sweat losses, maintaining plasma sodium (140 [3]mmol·L-1), and dehydrating by 4.1% (1.3%). Mean maximum Tc was 39.0 (0.5) (range 38.2-40.1 °C) with 90% of race duration ≤39.0 °C. Mean maximum ΔTc was 1.9 (0.9) (0.9-2.7 °C) with 95% of race duration ≤2.0 °C. Over 0 to 45km, associations between ΔTc and peak oxygen uptake (positive) and body fat (negative) were observed. Over 58 to 89km, associations between Tc and peak oxygen uptake (negative) and body fat (positive) were observed. Modest Tc responses were observed in recreational ultramarathon runners. Runners with higher levels of aerobic fitness and lower levels of body fat demonstrated the greatest changes in Tc during the first half of the race. Conversely, runners with lower levels of aerobic fitness and higher levels of body fat demonstrated the greatest absolute Tc in the final third of the race.

Correlation between Cardiopulmonary Indices and Running Performance in a 14.5 km Endurance Running Event.

Background: Running is a common recreational activity, and the number of long-distance-race participants is continuously growing. It is well-established that regular physical activity can prevent and manage non-communicable diseases and benefit public health. Training for a long-distance race requires development of specific aerobic abilities and should generate the desired race performance. The purpose of this study was to support the training design and motivation of recreational endurance runners, by investigating whether a 14.5 km race performance of long-distance runners correlates with their cardiopulmonary indices measured in the laboratory. Methods: To examine the relationships of a 14.5 km running performance with the cardiopulmonary parameters of amateur runners, a cross-sectional study design was applied. Fifteen (eleven men and four women) recreational long-distance runners (aged 41.3 ± 9.2 years) from Northern Greece were included in the study and were evaluated in the laboratory within one week before an endurance running race—the 14.5 km Philip Road race, in Greece. The laboratory-based examinations of the athletes consisted of a comprehensive medical pre-participation screening and maximal cardiopulmonary exercise testing. Results: The results showed that the 14.5 km race performance time (73.8 ± 9.7 min) significantly correlated with the cardiopulmonary-exercise-testing speed-related indices at specific submaximal and maximal workloads (p < 0.01, p < 0.05), while the cardiopulmonary indices of oxygen uptake did not reliably predict race running time (p > 0.05). Conclusions: There is a better correlation of the 14.5 km running performance of recreational long-distance runners with the cardiopulmonary-exercise-testing speed-related indices at specific workloads than with the indices of oxygen uptake, running economy or respiratory economy. When preparing a training strategy, amateur long-distance runners should mostly rely on specific running-speed-related laboratory data rather than on oxygen-uptake values.

Comparison of different models of Wʹ balance in high-level road cycling races

ABSTRACT This study aimed to compare different models of Wʹ balance (Wʹbal) during road cycling races. These models allow tracking of the depletion and reconstitution of energy reserves during intermittent exercises. Fifteen high-level cyclists shared a year of data, including the power output and GPS records. They then selected a race during which they were in very good condition, and where they reached a maximum level of exhaustion in the final phase. Based on their seasonal data, their critical power and Wʹ were calculated and incorporated into the integral and differential models of Skiba and Bartram model. Wʹbal was calculated throughout the races and normalised to Wʹ. The integral, differential, and Bartram models predicted a mean Wʹbal of 41 ± 27%, 67 ± 17%, and 82 ± 9%, a minimum Wʹbal of −21 ± 28%, −3 ± 22%, and 22 ± 24%, and a Wʹbal at the identified point of exhaustion of 0 ± 30%, 21 ± 28%, and 42 ± 23% (all significantly different, p < 0.01). Given the large differences between the models and the high inter-individual variability of Wʹbal at the participant-identified point of exhaustion, this study shows that the models are not interchangeable and that the values of Wʹbal should be considered with caution when analysing races.

Nutritional intake when cycling under racing and training conditions in professional male cyclists with type 1 diabetes

ABSTRACT This study sought to detail and compare the in-ride nutritional practices of a group of professional cyclists with type 1 diabetes (T1D) under training and racing conditions. We observed seven male professional road cyclists with T1D (Age: 28 ± 4 years, HbA1c: 6.4 ± 0.4% [46 ± 4 mmol.mol−1], VO2max: 73.9 ± 4.3 ml.kg −1.min−1) during pre-season training and during a Union Cycliste Internationale multi-stage road cycling race (Tour of Slovenia). In-ride nutritional, interstitial glucose, and performance variables were quantified and compared between the two events. The in-ride energy intake was similar between training and racing conditions (p = 0.909), with carbohydrates being the major source of fuel in both events during exercise at a rate of 41.9 ± 6.8 g.h−1 and 45.4 ± 15.5 g.h−1 (p = 0.548), respectively. Protein consumption was higher during training (2.6 ± 0.6 g.h−1) than race rides (1.9 ± 0.9 g.h−1; p = 0.051). A similar amount of time was spent within the euglycaemic range (≥70-≤180 mg.dL−1): training 77.1 ± 32.8% vs racing 73.4 ± 3.9%; p = 0.818. These data provide new information on the in-ride nutritional intake in professional cyclists with T1D during different stages of the competitive season.

COMPENSATORY RESERVE INDEX: NORMATIVE VALUES OF A NEW VITAL SIGN SURROUNDING EXERCISE IN THE HEAT

Hypovolemic shock is a threat to the health and safety of active individuals when exposed to extreme environmental conditions. Non-invasive measurement of central volume loss, opposed to traditional vital signs, has been shown to be a stronger indicator of the onset of hypovolemic shock resulting from dehydration or hemorrhage. Compensatory reserve index (CRI), a scale ranging from 0-1.0, categorizes the stages of shock as a predictive measure of the remaining reserve of blood volume before compensation is diminished. Utilization of CRI in a clinical setting has been validated, while normative values surrounding exercise have yet to be established. PURPOSE: To assess normative CRI values surrounding exercise in the heat in active adults. METHODS: Data was collected on 41 active adults who completed a 11 km road race. Age (mean ± standard deviation [SD]): 44.7 ± 15.7 years; VO2max: 42.7 ± 9.2 ml/kg/min; percent body fat: 22.4 ± 9.6%. CRI was assessed at baseline for 10 minutes in a supine position in a thermoneutral environment. At the road race, CRI was assessed for 2 minutes pre-race and post-race in the supine position. Heart rate and oxygen saturation were assessed alongside CRI. Environmental conditions were captured surrounding the race. Core temperature was assessed post-race. Descriptive statistics (mean ± SD) were calculated and paired-samples t-tests were utilized to compare baseline to pre-race, baseline to post-race, and pre-race to post-race. RESULTS: Post-race CRI (mean ± SD: 0.70 ± 0.32) significantly diminished compared to baseline values (0.91 ± 0.07; p < 0.001). Post-race CRI was significantly diminished (p < 0.001) compared to pre-race CRI measures (mean ± SD: 0.88 ± 0.09). Resting heart rate increased from baseline (mean ± SD: 59.6 ± 10.4 bpm) to pre-race (65.4 ± 11.2 bpm) and to post-race (85.1 ± 16.9 bpm). Runners were characterized as hyperthermic following the race (core temperature: 38.90 ± 1.20 °C). Environmental conditions upon finishing the race were 22.78 °C, 53% RH, and 21.67 °C WBGT. CONCLUSIONS: Following physically demanding exercise in the heat, CRI monitoring may be able to detect changes resulting from increased physiological stress and may be utilized to prevent collapse. Future studies should assess the extent to which thermal stress is correlated to changes in CRI.