Open Water Swimming Research Articles

Case Study: Comparison of Swimsuits and Wetsuits Through Biomechanics and Energetics in Elite Female Open Water Swimmers

The authors investigated how the Arena Powerskin R-EVO Closed Back swimsuit and Arena Carbon Triwetsuit (full-sleeve wetsuit), both approved by the Fédération Internationale de Natation (FINA) regulations, affect biomechanics and energetics of 3 elite female open water (OW) swimmers at maximal and 4 submaximal swimming intensities. Three elite female OW swimmers (OW1 = 24y, 1.64m, 60kg; OW2 = 23y, 1.69m, 65kg; OW3 = 27y, 1.63m, 64.5kg) were tested 1 week prior to a FINA/CNSG (China National Sports Group) Marathon Swim World Series event and 40 days before the 18th FINA World Championships 2019. Each OW swimmer completed 2 identical testing sessions, one with a swimsuit and other with a wetsuit, involving shoulder flexion power output assessed from medicine-ball throw, maximal performance and drag coefficient assessment, and an incremental intermittent swim test at 4 different relative intensities. Estimated peak oxygen uptake was 4.4L·min-1 for OW1, 5.6L·min-1 for OW2, and 5.0L·min-1 for OW3. Despite a distinct behavior observed on index of coordination for OW3, a null index of synchronization, increased stroke rate (mean difference = 2%-8%), reduced drag factor (minimum = -14%; maximum = -30%), lower energy cost (mean difference = -2% to -6%), and faster performance (mean difference = 2% to 3%) were observed with the wetsuit compared with swimsuit for all elite OW swimmers. The wetsuit enhances submaximal swimming performance, and this increase is dependent on the OW swimmer's characteristics. The higher stroke rate and lower stroke length detected with wetsuit could be related to movement constraints imposed by the suit.

Examination of training intensity and stroke index in coaching 5 km open water swimming

Examination of training intensity and stroke index in coaching 5 km open water swimming

Swimming Induced Pulmonary Oedema is Not Cardiogenic in Long-Distance Open-Water Swimmers

Swimming induced pulmonary oedema (SIPE) is a potentially life-threatening condition associated with prolonged open-water swims. However, the contribution of cardiac versus non-cardiac causes to SIPE is unclear. This study aimed to assess the prevalence of SIPE in trained open-water swimmers, and determine associations between SIPE and changes in cardiac function.

Thermal Strain During Open-Water Swimming Competition in Warm Water Environments.

Open-water swim racing in warm water is associated with significant physiological strain. However, existing international policy that governs safe participation during competition relies only on a fixed water temperature threshold for event cancellation and has an unclear biophysical rationale. The current policy does not factor other environmental factors or race distance, nor provide a stratification of risk (low, moderate, high, or extreme) prior to the threshold for cancellation. Therefore, the primary aim of this Perspectives article is to highlight considerations for the development of modernized warm-water competition policies. We highlight current accounts (or lack thereof) of thermal strain, cooling interventions, and performance in warm-water swimming and opportunities for advancement of knowledge. Further work is needed that systematically evaluate real-world thermal strain and performance during warm water competition (alongside reports of environmental conditions), novel preparatory strategies, and in-race cooling strategies. This could ultimately form a basis for future development of modernized policies for athlete cohorts that stratifies risk and mitigation strategies according to important environmental factors and race-specific factors (distance).

Water quality for triathlon and open water swimming competitions in Brazilian freshwaters

Abstract In high-performance competitive activities, there can be intense and prolonged exposure to water during swimming components of the competition. Therefore, water quality assessments with reference to standards are desirable to ensure athletes’ health. We evaluated whether the official criteria established for primary contact recreation in Brazilian freshwaters (CONAMA Directive 274/2000), and an integrated index of bathing conditions in Brazil (ICB), are consistent with the water quality standards stipulated by the International Triathlon Union (ITU). The water quality of Lake of Ingleses, an important venue for triathlon and open water swimming near Belo Horizonte, Minas Gerais, Brazil, was assessed between 2003 and 2019. Results for E. coli, cyanobacteria density, and pH were favorable for contact recreation and competitions at the lake. Of the variables considered, only turbidity, used as a proxy indicator of visual water clarity, was unsuitable during part of the monitoring period. The ICB agreed with the ITU standards for Very Good and Excellent quality classes and is recommended as a tool for screening sites considered for competitions in Brazilian freshwaters. However, the Brazilian national criteria for contact recreation only present standards for E. coli and pH, which is insufficient coverage of attributes affecting primary contact suitability of water in high-performance sports activities.

The meaning of open-water swimming for adults in Ireland: a qualitative study

Purpose There has been an increase in swimming in natural bodies of water as reported in personal qualitative accounts. However, limited academic research has explored the meaning of this occupation. Engaging with nature, exercising and being part of a community contribute to better mental and physical health. The purpose of this research was to explore the meaning that adults attribute to open-water swimming in natural bodies of water. Design/methodology/approach This study used phenomenological interviews to explore the meaning that five adults attribute to open-water swimming. Findings Open-water swimming contributes to meaning-making in many ways. Participants reported swimming as necessary for maintaining mental and emotional well-being and forming meaningful connections with the social environment, nature and their true selves. Research limitations/implications This study contributes to the understanding of the meaning of open-water swimming for adults in Ireland. Understanding the meaning of this occupation may add to the body of evidence exploring blue-space to promote health. Originality/value Open-water swimming is an occupation growing in popularity. This is the first paper to explore open-water swimming from an occupational perspective. This may provide an alternative perspective for viewing blue-space engagement and understanding the relationship between health, blue-space occupations and our oceans.

Origin of the Fastest 5 km, 10 km and 25 km Open-Water Swimmers-An Analysis from 20 Years and 9819 Swimmers.

In elite pool swimmers competing at world class level, mainly athletes from the United States of America and Australia are dominating. Little is known, however, for the nationality of dominating swimmers in elite open-water long-distance swimming races such as the official FINA races over 5 km, 10 km and 25 km—held since 2000. The aim of this study was to investigate the participation and performance trends by nationality of these elite open-water swimmers. Race results from all female and male swimmers competing in 5 km, 10 km and 25 km FINA races between 2000 and 2020 were analyzed. A total of 9819 swimmers competed between 2000 and 2020 in these races. The five countries that figure most times among the top ten in 5 km, 10 km and 25 km races over the years were Italy, Germany, Russia, Brazil and the Netherlands. In 10 km races, considering the all the athletes from each country, male athletes from Germany, Italy, and France presented faster race times than the other countries. In 10 km, female athletes presented no significant difference among the countries. In 5 and 25 km races, there were no differences between countries, for male and female athletes. Moreover, comparing only the 10 best results (top 10) from each country, there were no differences between countries in 5 km, 10 km and 25 km, for male and female athletes. Men were faster than women for all three distances. In summary, male swimmers from Europe (i.e., Germany, Italy, France) are dominating the 10 km FINA races. In the 5 km and 25 km FINA races, there is no dominating nationality, but among the top five countries in the top 10 over the years, three are European countries.

Beneath the Surface: Mental Health and Harassment and Abuse of Athletes Participating in the FINA (Aquatics) World Championships, 2019.

To assess the mental health and experience of sport-related harassment and abuse of elite aquatic athletes and to analyze it in relation to gender and discipline. Cross-sectional study using an anonymous survey. The FINA World Championships 2019. Registered athletes in the disciplines of swimming, diving, high diving, water polo, artistic swimming, and open water swimming. Athletes completed an online or paper-based questionnaire. The main outcome measures included screening for depression (10-item version of the Center for Epidemiological Studies Depression Scale revised), eating disorders (Brief Eating Disorders in Athletes Questionnaire), the subjective need for psychotherapeutic support, and the experience of sport-related harassment and/or abuse. A quarter (24.6%) of the 377 responding athletes were classified as depressed and 2.5% as having an eating disorder. More than 40% of the athletes stated that they wanted or needed psychotherapeutic support. Fifty-one athletes (14.9%) had experienced harassment/abuse in sport themselves, and 31 (9%) had witnessed it in another athlete. The experiences of harassment and abuse ranged from unwanted comments about body or appearance (40.2%) to rewards in sport for sexual favors (2.5%) and rape (0.3%). Athletes who had experienced harassment/abuse in sport themselves had higher average scores for depression and eating disorders, and more of them felt they needed psychotherapeutic support. Up to a third would not talk or report to anybody if they saw or experienced harassment/abuse, and less than 20% would talk to an official for help. Targeted initiatives are required to address mental health issues and harassment and abuse in sport in the FINA aquatic disciplines.

Wetsuit Use During Open Water Swimming. Does It "Suit" Everybody? A Narrative Review.

Although wearing a wetsuit while swimming, when permitted, is primarily for safety reasons (ie,to protect against hypothermia), changes in buoyancy, biomechanics, and exercise performance have been reported. This narrative review covers the benefits of different wetsuit models on performance in swimming and triathlon. A computer search of online databases was conducted to locate relevant published research until March 2021. After the screening process, 17 studies were selected for analysis. Most of the selected studies involved pool swimmers or triathletes completing short or middle distances in a pool while using a full or a long sleeveless wetsuit. Swimming with wetsuit elicited significant improvements in performance (maximum 11%), mainly by decreasing drag and energy cost, by increasing buoyancy, and by affecting technique. Different rates of change in each factor were found according to swimming ability and wetsuit model. In addition, wearing a wetsuit was often rated as uncomfortable by athletes. Although improvement in swimming performance by wearing a wetsuit has been reported in the literature, the amplitude of the improvement remains questionable. The enhancement in swimming performance is attributable merely to improvements in propulsion proficiency and buoyancy, as well as a reduction in drag. The extent to which athletes are familiar with the use of a wetsuit, their swimming ability, and the wetsuit model may play important roles in this improvement. More studies simulating competition and comparing elite versus nonelite athletes are needed.

Cardiac and Pulmonary Vascular Remodeling in Endurance Open Water Swimmers Assessed by Cardiac Magnetic Resonance: Impact of Sex and Sport Discipline.

Background: The cardiac response to endurance exercise has been studied previously, and recent reports have described the extension of this remodeling to the pulmonary vasculature. However, these reports have focused primarily on land-based sports and few data are available on exercise-induced cardio-pulmonary adaptation in swimming. Nor has the impact of sex on this exercise-induced cardio-pulmonary remodeling been studied in depth. The main aim of our study was to evaluate cardiac and pulmonary circulation remodeling in endurance swimmers. Among the secondary objectives, we evaluate the impact of sex and endurance sport discipline on this cardio-pulmonary remodeling promoted by exercise training.Methods:Resting cardiovascular magnetic resonance imaging was performed in 30 healthy well-trained endurance swimmers (83.3% male) and in 19 terrestrial endurance athletes (79% male) to assess biventricular dimensions and function. Pulmonary artery dimensions and flow as well as estimates of pulmonary vascular resistance (PVR) were also evaluated.Results:In relation to the reference parameters for the non-athletic population, male endurance swimmers had larger biventricular and pulmonary artery size (7.4 ± 1.0 vs. 5.9 ± 1.1 cm2, p < 0.001) with lower biventricular ejection fraction (EF) (left ventricular (LV) EF: 58 ± 4.4 vs. 67 ± 4.5 %, p < 0.001; right ventricular (RV) EF: 60 ± 4 vs. 66 ± 6 %, p < 0.001), LV end-diastolic volume (EDV): 106 ± 11 vs. 80 ± 9 ml/m2, p < 0.001; RV EDV: 101 ± 14 vs. 83 ± 12 ml/m2, p < 0.001). Significantly larger LV volume and lower LV EF were also observed in female swimmers (LV EF: 60 ± 5.3 vs. 67 ± 4.6 %, p = 0.003; LV EDV: 90 ± 17.6 vs. 75± 8.7 ml/m2, p = 0.002). Compared to terrestrial endurance athletes, swimmers showed increased LV indexed mass (75.0 ± 12.8 vs. 61.5 ± 10.0 g/m2, p < 0.001). The two groups of endurance athletes had similar pulmonary artery remodeling.Conclusions: Cardiac response to endurance swimming training implies an adaptation of both ventricular and pulmonary vasculature, as in the case of terrestrial endurance athletes. Cardio-pulmonary remodeling seems to be less extensive in female than in male swimmers.

Elderly common bottlenose dolphins show signs of ageing like humans

Anyone who has tried their hand swimming in open water in northern locales knows that first dip can be excruciating; it feels as if every stinging ounce of warmth is being stripped from your skin. Yet, warm blooded whales, dolphins and seals must continually defend and stoke their warmth to maintain their temperature, impacting the amount of energy they must consume. ‘Determining their daily energy requirements will help us to better understand where they go, find food and whether they influence their prey’, says Rebecca Rimbach from Duke University, USA. However, measuring the amount of energy used by freely roaming creatures is notoriously difficult. Some researchers have successfully recorded the metabolic rate of resting seals, porpoises and dolphins, but that is a far cry from the total exertion of these animals as they scour the sea. Fortunately, Herman Pontzer and Brian Hare (both from Duke University) knew of an alternative technique – when animals consume so-called ‘heavy’ water – that can be used to monitor their total energy expenditure over an extended period, which they hoped could provide a glimpse into the cost of an aquatic lifestyle for common bottlenose dolphins.Hannah Salomons, Ahmad Amireh and Chana Kaufman (all from Duke University) joined Emily Guarino at the Dolphin Research Center (FL, USA), while Austin Allen (Duke University) travelled to Dolphin Quest (HI, USA) to measure the mammals’ energy use, providing 10 common bottlenose dolphins – ranging in age from 10 to 45 years – with a drink of heavy water enriched with deuterium (2H) and with heavy oxygen (18O). Guarino explains that the dolphins regularly drink water from a tube, ‘so that even if they become ill and reduce their food intake, they can still receive their necessary hydration’. Then, the team kept track of the dolphins’ activity as the animals cavorted in their lagoons, how much fish they consumed and their body weight. In addition, they collected blood and urine samples over 9 days to keep track of how much heavy water the animals lost. ‘The dolphins already cooperate in their own health care, so voluntarily give blood and urine samples’, Guarino explains, adding with a smile, ‘One of the dolphins, Talon, was so proud of himself after giving samples, that he always raced around the lagoon in a giant victory lap!’. Knowing that the cetaceans would gradually lose heavy oxygen in the form of water and carbon dioxide, while the deuterium would only be lost as water, the team could use the heavy water measurements to keep track of how much carbon dioxide the animals exhaled and, consequently, how much energy they used.Back at Duke University, Rimbach calculated the dolphins’ total energy expenditure and, sure enough, the animals were consuming more energy than terrestrial mammals to fuel their warm-blooded aquatic lifestyle; however, they were using 17% less energy than other similarly sized aquatic mammals. Most surprisingly, the older dolphins used significantly less energy than the youngsters when their size had been taken into account. ‘We were surprised to find this age difference in energy expenditure because this pattern has not been reported in other long-lived species, other than humans’, says Rimbach. In addition, the oldest dolphins were also carrying 8.4% more fat than their younger leaner pod-mates and had lost muscle, again much like elderly people.So, ageing common bottlenose dolphins appear to experience some of the same symptoms of physical decline as older humans, and Rimbach says that she would love to follow individual dolphins over the course of their lives, to track how their energy expenditure alters as they age; although she admits that would be challenging, thanks to their decades-long lifespans.

Italians Are the Fastest 3000 m Open-Water Master Swimmers in the World.

Background: It is well known that athletes originating from a specific region or country can master specific sports disciplines (e.g., East-African runners in long-distance running). In addition, physical and athletic performance are the result of an interaction between genetic, environmental and epigenetic factors. However, little is known about on what determines sports success and performance for long-distance master swimmers such as origin. The aim of the study was to investigate the participation and performance trends of elite master open-water swimmers competing in the World Championships (WC) in 3000 m open-water swimming between 1986 and 2019. Methods: A total of 9247 valid participants were analyzed using generalized linear models (GLMs) with a gamma probability distribution and log link function. Resultsː Most of the starters were from Italy (1646 participations), followed by the United States of America (USA) (1128 participations) and Germany (959 participations). Swimmers from Italy were significantly faster than swimmers from Canada, Germany, USA, Great Britain and also from all other countries grouped (p < 0.005). The age group from 35–39 years old was significantly faster than athletes from age groups of 25–29 years old, 30–34 years old, 40–44 years old, 45–49 years old and 50–54 years old (p < 0.005). The percentage of local athletes in WC was 36% and varied from 36% (Italy, 2004) to 43 % (Germany), 53% (Italy, 2012) and up to 68 % (USA, 1992). Conclusions: Swimmers from Italy were the faster and the most numerous starters during this period of 27 years and 15 editions all over the world in 3000 m master open-water swimming.

Sink or swim: innovations in aquatic health.

Since the first modern Olympic Games in 1896, the aquatic sports have expanded both in participation and innovation over the last century. Beginning with swimming, diving, water polo, and later additions of artistic swimming, open water swimming and high diving, the aquatics sports represent a core pillar of Olympic disciplines. The rapid expansion of aquatic disciplines necessitated the foundation of the Fédération Internationale de Natation (FINA) in 1908, to govern the development of aquatic sports. The amateur spectacle has been slowly replaced with an increased focus on health and performance by dedicated professional athletes and support teams, resulting in the development of new innovations. In the early years, innovations largely centered on technical equipment such as bathing suit and springboard design. In more recent years, research and innovation have shifted focus to health and its impact on performance, including but not limited to changes in training methods, nutrition, injury and illness reduction through surveillance and access to education for athletes, coaches, and support personnel. An increased awareness on factors that affect athlete health have also driven safety innovations including the development of Nutrition and Relative Energy Deficiency in Sport Clinical Assessment Tool, the Sport Mental Health Assessment and Recognition Tools and safeguarding from harassment and abuse through embedding athletes' right to safe sport in underpinning statutory documents. While the future of aquatic health innovations remains undefined, there are many potential opportunities for research and knowledge translation as the aquatic sports continue to evolve and adapt over time.

Incidence of Swimming-Induced Pulmonary Edema: A Cohort Study Based on 47,600 Open-Water Swimming Distances

BackgroundDespite increasing awareness of swimming-induced pulmonary edema (SIPE), large population-based studies are lacking and the incidence is unknown.Research QuestionWhat is the incidence of SIPE in a mixed group of competitive and recreational swimmers during a large open-water swimming event?MethodsIn four consecutive years (2016-2019), a prospective cohort study was conducted during Sweden’s largest open-water swimming event, Vansbrosimningen. All swimmers seeking medical care with acute respiratory symptoms were eligible for the study. SIPE diagnosis was based on clinical findings in 2016 and 2017 and pulmonary edema assessed by lung ultrasound in 2018 and 2019. Data on patient characteristics, clinical findings, and information about the race were collected.ResultsBased on 47,573 consecutive swimming distances, 322 patients with acute respiratory symptoms (0.68%; CI, 0.61%-0.75%) were treated at the mobile medical unit. Of these, 211 patients (0.44%; CI, 0.39%-0.51%) received a diagnosis of SIPE. The annual incidence of SIPE was 0.34%, 0.47%, 0.41%, and 0.57%, respectively, from 2016 through 2019. Most patients diagnosed with SIPE were women (90%), despite about equal percentages of men and women participating (47% men and 53% women). The incidence of SIPE overall was 0.75% in women and 0.09% in men. The incidence increased with age, from 0.08% in the youngest age group (18-30 years) to 1.1% in the oldest age group (≥ 61 years). Based on multiple logistic regression analysis, the adjusted odds for SIPE occurring was 8.59 times higher for women compared with men and 12.74 times higher for the oldest age group compared with the youngest age group.InterpretationThe incidence of SIPE over 4 years during a large open-water swimming event in Sweden was 0.44%. The incidence was higher in women than in men and increased with age.

Stroking Rates of Open Water Swimmers during the 2019 FINA World Swimming Championships.

The aim of the present research was to examine the stroking rate (SR) values of successful and non-successful swimmers in the 10 km and 25 km races of the FINA 2019 World Swimming Championships. Data from 175 participants (95 men and 80 female) were classified according to their finishing positions. There were no meaningful differences in the overall SR values displayed by successful or non-successful participants during the 10 km and 25 km open water races of the FINA 2019 World Swimming Championships. However, there were changes in the SR throughout the races that depended on the swimmer’s performance group and gender. Successful swimmers in the 10 km event typically displayed even SR in the first 5 km but, unlike the remaining performance groups, increased their SR at some point in the second 5 km of the race. In the 25 km race, successful female swimmers presented an even SR profile for most of the race, whereas successful males presented a more variable profile. Nevertheless, no relationships between partial or average SR and finishing positions occurred, either in the 10 km or in the 25 km race. Changes in the SR values should be included in the race plan of open water swimmers according to tactical and pacing strategies.

Examining the relationship between arterial stiffness and swim-training volume in elite aquatic athletes.

Factors such as prone body position, hydrostatic pressure, and intermittent breath-holding subject aquatic athletes to unique physical and environmental stressors during swimming exercise. The relationship between exposure to aquatic exercise and both arterial stiffness and wave reflection properties is not well-understood. This study assessed central artery stiffness and wave reflection properties in elite pool-swimmers (SW), long-distance open-water swimmers (OW), and water polo players (WP) to examine the relationship between these variables and aquatic exercise. Athletes competing in SW, OW and WP events at the FINA World Championships were recruited. Carotid-femoral pulse wave velocity, and pulse wave analysis were used to quantify arterial stiffness, and central wave reflection properties. Athletes undertook differing amounts of weekly swimming distance in training according to their discipline (SW: 40.2 ± 21.1km, OW: 59.7 ± 28.4km, WP: 11.4 ± 6.3km; all p < 0.05). Pulse wave velocity (Males [SW: 6.0 ± 0.6m/s, OW: 6.5 ± 0.8m/s, WP: 6.7 ± 0.9m/s], Females [SW: 5.4 ± 0.6m/s, OW: 5.3 ± 0.5m/s, WP: 5.2 ± 0.8m/s; p = 0.4]) was similar across disciplines for females but was greater in male WP compared to male SW (p = 0.005). Augmentation index (Males [SW: -3.4 ± 11%, OW: -9.6 ± 6.4%, WP: 1.7 ± 10.9%], Females [SW: 3.5 ± 13.5%, OW: -13.2 ± 10.7%, WP: -2.8 ± 10.7%]) was lower in male OW compared to WP (p = 0.03), and higher in female SW compared to OW (p = 0.002). Augmentation index normalized to a heart rate of 75bpm was inversely related to weekly swim distance in training (r = -0.27, p = 0.004). This study provides evidence that the central vasculature of elite aquatic athletes differs by discipline, and this is associated with training load.

Spatial-temporal variables for swimming coaches: A comparison study between video and TritonWear sensor

The main aim of this study was to evaluate the validity and the reliability of a swimming sensor to assess swimming performance and spatial-temporal variables. Six international male open-water swimmers completed a protocol which consisted of two training sets: a 6×100m individual medley and a continuous 800 m set in freestyle. Swimmers were equipped with a wearable sensor, the TritonWear to collect automatically spatial-temporal variables: speed, lap time, stroke count (SC), stroke length (SL), stroke rate (SR), and stroke index (SI). Video recordings were added as a “gold-standard” and used to assess the validity and the reliability of the TritonWear sensor. The results show that the sensor provides accurate results in comparison with video recording measurements. A very high accuracy was observed for lap time with a mean absolute percentage error (MAPE) under 5% for each stroke (2.2, 3.2, 3.4, 4.1% for butterfly, backstroke, breaststroke and freestyle respectively) but high error ranges indicate a dependence on swimming technique. Stroke count accuracy was higher for symmetric strokes than for alternate strokes (MAPE: 0, 2.4, 7.1 &amp; 4.9% for butterfly, breaststroke, backstroke &amp; freestyle respectively). The other variables (SL, SR &amp; SI) derived from the SC and the lap time also show good accuracy in all strokes. The wearable sensor provides an accurate real time feedback of spatial-temporal variables in six international open-water swimmers during classical training sets (at low to moderate intensities), which could be a useful tool for coaches, allowing them to monitor training load with no effort.

Risk Factors and Predictors of Hypothermia and Dropouts During Open-Water Swimming Competitions

To measure core temperature (Tcore) in open-water (OW) swimmers during a 25-km competition and identify the predictors of Tcore drop and hypothermia-related dropouts. Twenty-four national- and international-level OW swimmers participated in the study. Participants completed a personal questionnaire and a body fat/muscle mass assessment before the race. The average speed was calculated on each lap over a 2500-m course. Tcore was continuously recorded via an ingestible temperature sensor (e-Celsius, BodyCap). Hypothermia-related dropouts (H group) were compared with finishers (nH group). Average prerace Tcore was 37.5°C (0.3°C) (N = 21). 7 participants dropped out due to hypothermia (H, n = 7) with a mean Tcore at dropout of 35.3°C (1.5°C). Multiple logistic regression analysis found that body fat percentage and initial Tcore were associated with hypothermia (G2 = 17.26, P < .001). Early Tcore drop ≤37.1°C at 2500 m was associated with a greater rate of hypothermia-related dropouts (71.4% vs 14.3%, P = .017). Multiple linear regression found that body fat percentage and previous participation were associated with Tcore drop (F = 4.95, P = .019). There was a positive correlation between the decrease in speed and Tcore drop (r = .462, P < .001). During an OW 25-km competition at 20°C to 21°C, lower initial Tcore and lower body fat, as well as premature Tcore drop, were associated with an increased risk of hypothermia-related dropout. Lower body fat and no previous participation, as well as decrease in swimming speed, were associated with Tcore drop.

Heat Injury in Open-Water Swimming: A Narrative Review.

Swimming is one of the most popular sports in the world with open-water swimming (OWS) gaining more and more prominence since being featured in the Federation Internationale De Natation World Aquatics Championships in 1992 and the Olympic Games in 2000. The aim of this review is to analyze the existing literature on heat injury in OWS. Relevant literature was located via computer-generated citations during November of 2020 through online computer searches of multiple major databases. Athletes participating in OWS are exposed to environmental conditions that place them at risk for unique medical conditions such as heat injury. Clinicians providing care for OWS athletes should be educated and trained to recognize these conditions and minimize risks to optimize athlete safety. This article identifies medical challenges related to heat injury in OWS while investigating water temperature recommendations, physiological effects of hyperthermia, risk mitigation strategies, and treatment measures.

Monitoring Rating of Perceived Exertion Time in Zone: A Novel Method to Quantify Training Load in Elite Open-Water Swimmers?

To analyze training-intensity distribution (TID) using different independent monitoring systems for internal training load in a group of elite open-water swimmers. One hundred sixty training sessions were monitored in 4 elite open-water swimmers (2 females and 2 males: 23.75 [4.86]y, 62.25 [6.18]kg, 167 [6.68]cm) during 5 weeks of regular training. Heart-rate-based methods, such as time in zone (TIZ), session goal (SG), and hybrid (SG/TIZ), were used to analyze TID. Similarly to SG/TIZ, a new hybrid approach, the rating of perceived exertion (RPE)/TIZ for a more accurate analysis of TID was used. Moreover, based on the 3-zone model, the session ratings of perceived exertion of the swimmers and the coach were compared. Heart-rate- and RPE-based TID methods were significantly different in quantifying Z1 (P = .012; effect size [ES] = 0.490) and Z2 (P = .006; ES = 0.778), while no difference was observed in the quantification of Z3 (P = .428; ES = 0.223). The heart-rate-based data for Z1, Z2, and Z3 were 83.2%, 7.4%, and 8.1% for TIZ; 80.8%, 8.3%, and 10.8% for SG/TIZ; and 55%, 15.6%, and 29.4% for SG. The RPE-based data were 70.9%, 19.9%, and 9.2% for RPE/TIZ% and 41.2%, 48.9%, and 9.7% for the session rating of perceived exertion. No differences were observed between the coach's and the swimmers' session ratings of perceived exertion in the 3 zones (Z1: P = .663, ES = -0.187; Z2: P = .110, ES = 0.578; Z3: P = .149, ES = 0.420). Using RPE-based TID methods, Z2 was significantly larger compared with Z1. These results show that RPE-based TID methods in elite open-water swimmers are affected by both intensity and volume.