Shoulder Pain in Competitive Swimmers: A Multi-Site Survey Study.

Background: There are 2.8 million youth competitive swimmers in the United States (US), and shoulder pain is the most common complaint among swimmers. Purpose: To determine prevalence of shoulder pain, disability, and dissatisfaction in youth competitive swimmers. A secondary purpose was to determine influence of age, competitive swimming experience, and previous history of shoulder pain or injury on shoulder pain, disability, and dissatisfaction, and finally to determine if sex, geographic area, and participation in a second sport relate to shoulder pain, disability, and dissatisfaction. Study Design: Multi-site cross-sectional design. Methods: Six-hundred and seventy-one swimmers aged 9-17 years from six states in the US completed surveys which included demographics, the Penn Shoulder Score (PSS), and the Disability of Arm Shoulder Hand (DASH) Sports. Independent t-tests were used to compare pain, disability, dissatisfaction, the influence of age, sex, participation in second sport, geographic region, and history of shoulder pain. Linear regression analyses were performed to determine the interaction of these variables with reported pain and disability. Results: Forty-nine percent of swimmers had shoulder symptoms. Greater shoulder pain and disability were reported in 15 to 17-year-olds compared to 9 to 10-year-olds (pain and disability: p<0.001), in swimmers with greater versus less years of experience (pain and disability: p<0.001), and in swimmers from eastern versus western states (pain: p=0.001, disability: p=0.0014). Swimmers not participating in a second sport had higher shoulder dissatisfaction (p=0.002). History of prior shoulder pain/traumatic injury was the best indicator of increased pain, disability, and dissatisfaction (p<0.001). Conclusion: Almost half of swimmers surveyed had shoulder pain, with a higher prevalence found in older age groups, those with greater experience, and in those with prior shoulder pain or traumatic injury. Further research should investigate shoulder pain prevention programs, and surveillance methods are recommended to identify symptomatic swimmers who may benefit from referral to prevent further pain and disability. Level of Evidence: III.

Identifying evidence-practice gaps for shoulder injury risk factors in competitive swimmers: uniting literature and expert opinion.

OBJECTIVES: To identify evidence-practice gaps regarding shoulder injury risk factors in competitive swimmers. METHODS: We gathered insights from 27 swimming experts including elite swimmers, coaches, high-performance staff and applied researchers using Concept Mapping. Participants brainstormed, sorted and rated (from 1 (least) to 10 (most) important and modifiable) their ideas of shoulder injury risk factors in competitive swimmers. Proposed risk factors rated above the grand mean for importance (6.2±0.4) or modifiability (6.5±0.5) ratings were considered highly important/modifiable. Expert opinions were then juxtaposed with systematic review findings to identify overlaps or convergences. RESULTS: Brainstorming generated 126 proposed shoulder injury risk factors for competitive swimmers, subsequently refined to 61 unique proposed risk factors by removing duplicates and combining similar responses. The participants sorted the 61 risk factors into seven distinct clusters. Experts perceived 36/61 proposed risk factors as highly important, of which 6 were supported by literature, 6 showed no association with injury, 2 had conflicting evidence and the remaining 22 have not yet been investigated, suggesting an evidence-practice gap. Three proposed risk factors 'inconsistent training load', 'poor stroke technique' and 'low posterior shoulder strength-endurance' exhibited high perceived importance, high perceived modifiability and supporting evidence. CONCLUSION: An evidence-practice gap was identified for 28 proposed risk factors perceived as highly important by swimming experts despite either (1) no relevant empirical research (n=22), or (2) no association with injury (n=6) from synthesised evidence. Greater collaboration between researchers and practitioners is needed to effectively address shoulder injury risk factors in competitive swimmers.

Directional swimming patterns in jellyfish aggregations.

Having a profound influence on marine and coastal environments worldwide, jellyfish hold significant scientific, economic, and public interest.1,2,3,4,5 The predictability of outbreaks and dispersion of jellyfish is limited by a fundamental gap in our understanding of their movement. Although there is evidence that jellyfish may actively affect their position,6,7,8,9,10 the role of active swimming in controlling jellyfish movement, and the characteristics of jellyfish swimming behavior, are not well understood. Consequently, jellyfish are often regarded as passively drifting or randomly moving organisms, both conceptually2,11 and in process studies.12,13,14 Here we show that the movement of jellyfish is modulated by distinctly directional swimming patterns that are oriented away from the coast and against the direction of surface gravity waves. Taking a Lagrangian viewpoint from drone videos that allows the tracking of multiple adjacent jellyfish, and focusing on the scyphozoan jellyfish Rhopilema nomadica as a model organism, we show that the behavior of individual jellyfish translates into a synchronized directional swimming of the aggregation as a whole. Numerical simulations show that this counter-wave swimming behavior results in biased correlated random-walk movement patterns that reduce the risk of stranding, thus providing jellyfish with an adaptive advantage critical to their survival. Our results emphasize the importance of active swimming in regulating jellyfish movement and open the way for a more accurate representation in model studies, thus improving the predictability of jellyfish outbreaks and their dispersion and contributing to our ability to mitigate their possible impact on coastal infrastructure and populations.

Critical swimming speed at different temperatures for small-bodied freshwater native riverine fish species.

This study evaluated the effect of fish total length (LT) and three water temperatures (10, 15 and 20 °C) on the critical swimming speed (Ucrit) of the species Percilia irwini (2.9-6.3 cm LT), Cheirodon galusdae (3.4-5.5 cm LT), and Trichomycterus areolatus (4.0-6.3 cm LT). An Ucrit estimation model was constructed for each species as a function of temperature and size. The results showed mean Ucrit for P. irwini of 44.56, 53.83 and 63.2 cm s-1 at 10, 15 and 20 °C, respectively: 55.34, 61.74 and 70.05 cm s-1 for C. galusdae and 56.18, 63.01 and 71.09 cm s-1 for T. areolatus. Critical velocity depended on the interaction between species, body length and water. The swimming performance increased significantly with rising temperature in all three species. The velocity also increased with greater fish total length. After controlling for fish total length, velocity also increased with higher temperature in the three species. This research is relevant to small fish species that require conservation measures.

The methodology of resistance training is crucial for improving short-medium distance front crawl performance in competitive swimmers: a systematic review and meta-analysis.

Background: Resistance training is often a part of the routine training regimen for competitive swimmers. However, due to the variety of resistance training methodology, the results can be inconsistent and sometimes unsatisfactory. Clear recommendations are still lacking at present. Aims: 1) Quantify the impact of resistance training on swimmers' upper limb maximum strength, front crawl performance and key technical parameters; 2) Find out the key technical parameters for improving front crawl performance-stroke rate or length; 3) Through subgroup analysis determine the best methodology of resistance training to enhance the front crawl. Methods: Systematic search in the PubMed, Embase, and Web of Science databases. Meta-analyses using the inverse-variance are performed to compare swimmers' upper limb maximum strength, front crawl performance and key technical parameters in resistance training and habitual aquatic training. A subgroup analysis was performed to examine whether the results were affected by the methodology of resistance training. Results: Thirteen studies (267 competitive swimmers) met the inclusion criteria. The results of meta-analysis showed that resistance training significantly improved upper limbs maximum muscle strength, and 25, 50, 100, and 200 m front crawl performance in competitive swimmers. And improvements in swimming performance may simply resulted from resistance training increasing stroke rate rather than stroke length. In addition, the results of subgroup analysis showed that only concurrent resistance training (CRT) and power training (PT) ultimately improved swimming performance by increasing the maximum muscle strength of the upper limbs. Conclusion: Resistance training significantly enhances competitive swimmers' upper limb strength and front crawl performance across various distances. The improvement in performance is likely attributed to an increased stroke rate rather than stroke length. In addition, CRT and PT are particularly effective, indicating the importance of selecting the appropriate methodology of resistance training for optimal swimming performance enhancement. Systematic review registration: https://doi.org/10.17605/OSF.IO/3JEGW.

Changes in Young Swimmers' In-Water Force, Performance, Kinematics, and Anthropometrics over a Full Competitive Season.

The aim of the present study was to analyze changes in young swimmers' in-water force, performance, kinematics, and anthropometrics during one full competitive season. Twenty-five swimmers (11 girls and 14 boys, 12.04 ± 0.16 years) were assessed over four distinct time points throughout a competitive season. The in-water force of both hands (D, dominant; ND, non-dominant) was retrieved during two bouts of 25 m front crawl allowing the estimation of the symmetry index. The velocity (v25) was calculated from the time to complete the 25 m and considered the performance outcome, while the stroke rate, stroke length, and the stroke index were used as kinematic variables. For anthropometric variables, body mass, stature, arm span and the hand surface area were measured. The in-water force (16-24%) and performance (8%) improved over the competitive season with significant changes in the first macrocycle. The stroke index was the only kinematic variable that changed between M1 and M4 (12.7%), accompanied by a higher asymmetric motion later in the season. A time effect was found in the stature (p < 0.001, ηp 2 = 0.71), the arm span (p < 0.001, ηp 2 = 0.79), and the hand surface area (D = p < 0.001, ηp 2 = 0.63; ND = p < 0.001, ηp 2 = 0.666). Swimming performance showed associations with in-water force, stroke efficiency and anthropometric features in all time points of the season. Thus, the natural anthropometric growth experienced over the season may translate into a more efficient swimming pattern with greater in-water forces that can enhance performance.

Mortality events associated with microsporidian, Spraguea sp., in White Trevally culture in Japan.

In 2021, White Trevally or Striped Jack cultured in the western part of Japan exhibited mild, but chronic mortalities from late September through early October. The cumulative mortality rate was approximately 0.02% per a net pen containing approximately 50,000 fish. Although the cumulative mortality rate was not high, most of the fish in net pens showed characteristic gross signs and an abnormal swimming behaviour. The body of diseased fish became pale and the yellow lines on the lateral sides of fish body became darken. In addition, silver lines along the dorsal fin became apparent. Loss of schooling behaviour was noted during the mortality event. In addition, affected fish became lethargic and failed to swim against current, or frequently stopped swimming and sank to the bottom of net pens after feeding. The goal of this study was to identify the cause of the mortality event. To achieve the goal, we used histopathology and metatranscriptome analysis. Histopathological examination revealed that xenoma of microsporidian were frequently observed in the nerve axon in the brain and spinal cord. Spores observed in the sections were stained with a fluorescent dye, Uvitex 2B, indicating those spores are microsporidian. The data from metatranscriptome analysis indicated that the microsporidian is Spraguea sp. The microsporidian was frequently detected from diseased fish with similar symptoms collected in the same region, suggesting that the microsporidian was highly associated with abnormal swimming behaviour of fish.

High water temperature significantly influences swimming performance of New Zealand migratory species.

Anthropogenic structures in freshwater systems pose a significant threat by fragmenting habitats. Effective fish passage solutions must consider how environmental changes introduce variability into swimming performance. As temperature is considered the most important external factor influencing fish physiology, it is especially important to consider its effects on fish swimming performance. Even minor alterations in water properties, such as temperature and velocity, can profoundly affect fish metabolic demands, foraging behaviours, fitness and, consequently, swimming performance and passage success. In this study, we investigated the impact of varying water temperatures on the critical swimming speeds of four migratory New Zealand species. Our findings revealed a significant reduction in critical swimming speeds at higher water temperatures (26°C) compared to lower ones (8 and 15°C) for three out of four species (Galaxias maculatus, Galaxias brevipinnis and Gobiomorphus cotidianus). In contrast, Galaxias fasciatus exhibited no significant temperature-related changes in swimming performance, suggesting species-specific responses to temperature. The cold temperature treatment did not impact swimming performance for any of the studied species. As high water temperatures significantly reduce fish swimming performance, it is important to ensure that fish passage solutions are designed to accommodate a range of temperature changes, including spatial and temporal changes, ranging from diel to decadal fluctuations. Our research underscores the importance of incorporating temperature effects into fish passage models for habitat restoration, connectivity initiatives, and freshwater fish conservation. The influence of temperature on fish swimming performance can alter migration patterns and population dynamics, highlighting the need for adaptive conservation strategies. To ensure the resilience of freshwater ecosystems it is important to account for the impact of temperature on fish swimming performance, particularly in the context of a changing climate.

Fish communicate with water flow to enhance a school's social network.

Schooling fish rely on a social network created through signaling between its members to interact with their environment. Previous studies have established that vision is necessary for schooling and that flow sensing by the lateral-line system may aid in a school's cohesion. However, it remains unclear to what extent flow provides a channel of communication between schooling fish. Based on kinematic measurements of the speed and heading of schooling tetras (Petitella rhodostoma), we found that compromising the lateral line by chemical treatment reduced the mutual information between individuals by ∼13%. This relatively small reduction in pairwise communication propagated through schools of varying size to reduce the degree and connectivity of the social network by more than half. Treated schools additionally showed more than twice the spatial heterogeneity of fish with unaltered flow sensing. These effects were much more substantial than the changes that we measured in the nearest-neighbor distance, speed, and intermittency of individual fish by compromising flow sensing. Therefore, flow serves as a valuable supplement to visual communication in a manner that is revealed through a school's network properties.

Negative prior aquatic experiences and children's aquatic competency: Do parent perceptions differ from reality?

ISSUE ADDRESSED: Achieving aquatic competence is recommended for preventing childhood drownings, yet many children in Victoria, Australia do not meet aquatic benchmarks despite participating in swimming and water safety programs. While few studies have explored factors influencing aquatic competency development, negative prior aquatic experiences (NPAE) have surfaced as a potential influence. Research on children's NPAE has primarily focused on parental perceptions rather than the child's actual experiences. METHODS: Parents and children (aged 10-12 years) completed reliable surveys for background information and NPAE-related data. Children also completed aquatic competency assessments against benchmark standards. Chi-square tests determined relationships between NPAE and aquatic competency, and thematic analysis categorised themes related to perceptions of the child's NPAE. RESULTS: Most parents (82.9%) indicated their child had not had NPAE, while only half (51.0%) of children did not report NPAE. Children reporting NPAE often perceived incidents as nearly drowning (41%), encompassing swimming pool environments and underwater submersion. Similarly, parents reported varied situations, noting NPAE involving open water and the child's loss of control. Parent-reported NPAE was associated with children less likely to achieve knowledge, continuous swimming, and survival competency benchmarks (p < .05). Children reporting NPAE were less likely to achieve underwater competencies (p < .05). CONCLUSIONS: The disparity between parent and child perspectives of NPAE demonstrates the importance of considering both perspectives. This should assist in providing appropriate support for children to develop aquatic competencies. SO WHAT?: Using NPAE data, practitioners can customise swim teaching approaches to address and prevent NPAE, particularly as many children associate their NPAE with pools, the common setting for aquatic education.

On-site extraction of benzophenones from swimming pool water using hybrid tapes based on the integration of hydrophilic-lipophilic balance microparticles and an outer magnetic nanometric domain.

An on-site extraction device is presented consisting of scotch tape modified with concentric domains of micrometric hydrophilic-lipophilic balance (HLB) particles surrounded by a ring of nanometric magnetic ones. On the one hand, HLB microparticles are readily available at the surface of the tape, exposed to interact with the target analytes, being responsible for the extraction capacity of the sorptive phase. On the other hand, the presence of magnetic nanoparticles enables the attachment of the modified tape onto a metallic screw via a magnet, which is then coupled to a wireless drill, enabling the stirring of the microextraction device. Both are simply fixed to the cost-effective, flexible, and versatile support, i.e., scotch tape, owing to their adhesive properties. The microextraction device has been applied to the determination of six benzophenones in swimming pool water samples. The variables that may affect the extraction process have been evaluated. Under the optimum conditions and using liquid chromatography-tandem mass spectrometry as the instrumental technique, the method provided a limit of detection of 0.03 µg L-1. The intra-day precision, evaluated at three different concentration levels and expressed as relative standard deviation, was lower than 10%, which also comprises the variability within single-use sorptive tapes. The accuracy, calculated with spiked samples and expressed as relative recovery, ranged from 71 to 138%. The method was applied to the analysis of swimming pool water, revealing the presence of such compounds.

Interactive effects of sedimentary turbidity and elevated water temperature on the Pugnose Shiner (Miniellus anogenus), a threatened freshwater fish.

High turbidity and elevated water temperature are environmental stressors that can co-occur in freshwater ecosystems such as when deforestation increases solar radiation and sedimentary runoff. However, we have limited knowledge about their combined impacts on fish behaviour and physiology. We explored independent and interactive effects of sedimentary turbidity and temperature on the swimming activity and both thermal and hypoxia tolerance of the Pugnose Shiner (Miniellus anogenus, formerly Notropis anogenus), a small leuciscid fish listed as Threatened under Canada's Species at Risk Act (SARA). Fish underwent a 15-week acclimation to two temperatures (16°C or 25°C) crossed with two turbidities (~0 NTU or 8.5 NTU). Swimming activity was measured during the first 8 weeks of acclimation. Fish in warm water were more active compared to those in cold water, but turbidity had no effect on activity. Behavioural response to hypoxia was measured after 12 weeks of acclimation, as the oxygen level at which fish used aquatic surface respiration (ASR). Fish in warm water engaged in ASR behaviour at higher oxygen thresholds, indicating less tolerance to hypoxia. Turbidity had no effect on ASR thresholds. Finally, thermal tolerance was measured as the critical thermal maximum (CTmax) after 13-15 weeks of acclimation. Acclimation to warm water increased fish CTmax and Tag (agitation temperature) but reduced the agitation window (°C difference between Tag and CTmax) and thermal safety margin (°C difference between the acclimation temperature and CTmax). Furthermore, fish in warm, turbid water had a lower CTmax and smaller thermal safety margin than fish in warm, clear water, indicating an interaction between turbidity and temperature. This reduced thermal tolerance observed in Pugnose Shiner in warm, turbid water highlights the importance of quantifying independent and interactive effects of multiple stressors when evaluating habitat suitability and conservation strategies for imperilled species.

Flagellar protein FliL: A many-splendored thing.

FliL is a bacterial flagellar protein demonstrated to associate with, and regulate ion flow through, the stator complex in a diverse array of bacterial species. FliL is also implicated in additional functions such as stabilizing the flagellar rod, modulating rotor bias, sensing the surface, and regulating gene expression. How can one protein do so many things? Its location is paramount to understanding its numerous functions. This review will look at the evidence, attempt to resolve some conflicting findings, and offer new thoughts on FliL.

Hydrophobia, dis/connection, and difference: Understanding Chinese immigrants' fear of coastal swimming in Aotearoa New Zealand.

New Zealand's coastal blue spaces, from harbours to beaches, provide diverse wellbeing benefits but can also be sites of danger, fear, and cultural contestation. This qualitative research focuses on Chinese migrants in Auckland, a community who are underrepresented in coastal recreation and overrepresented in drowning statistics. Findings show Chinese migrants dis/connection with coastal blue space and fear of coastal swimming, derived from their homeland habitus and lack of coastal 'blue space' cultural capital. Our research contributes to the growing recognition of 'hydrophobia', and how the racialisation of leisure space impacts the potential for blue spaces and practices to be therapeutic.

Long-distance swimming by African lions in Uganda.

Earth's most imperiled and iconic wildlife are facing tough decisions under increasing human pressure and limited resources. Swimming across rivers and water bodies filled with high densities of predators may be one such example. In African lions Panthera leo, previous water crossings (recorded in the peer-reviewed and gray literature, on film, and found using Google Search, and YouTube) have recorded distances ranging from <10 to 100 m, with some resulting in mortality by Nile Crocodiles Crocodylis niloticus. However, we observed a coalition of male lions swimming >1 km across Uganda's Kazinga channel located in the Queen Elizabeth National Park six times, and recorded this behavior on film on February 1st 2024. We speculate that three factors could be driving these lions to take long-distance swims with a high density of crocodiles and hippos Hippopotamus amphibius, namely (1) the lack of lionesses in this ecosystem, (2) intraspecific fights over territory with other male coalitions, and (3) the only other land connection giving lions access to the peninsula is a small road bridge with a strong human presence.

Form and function of anguilliform swimming.

Anguilliform swimmers are long and narrow animals that propel themselves by undulating their bodies. Observations in nature and recent investigations suggest that anguilliform swimming is highly efficient. However, understanding the underlying reasons for the efficiency of this type of locomotion requires interdisciplinary studies spanning from biology to hydrodynamics. Regrettably, these different fields are rarely discussed together, which hinders our ability to understand the repeated evolution of this swimming mode in vertebrates. This review compiles the current knowledge of the anatomical features that drive anguilliform swimming, compares the resulting kinematics across a wide range of anguilliform swimmers, and describes the resulting hydrodynamic interactions using data from both in vivo experiments and computational studies.

Development of an evidence-based swimming representative military task to assess swimming competency in the British Army.

BACKGROUND: There is a requirement for British Army personnel to operate in/around water. Assessing role-related swimming/water competence will support personnel to conduct their job-roles safely and effectively. OBJECTIVE: To undertake a Job-Task Analysis (JTA) of British Army personnel when working in/around water and use this information to develop a Swimming Representative Military Task (RMT) to assess swimming/water competence. METHODS: Workshops, surveys, and observations were used to conduct a JTA, which identified and described job-tasks conducted by British Army personnel in/around water. Ergonomic analysis of these job-tasks identified seven water-based physical actions, which were considered fundamental for all personnel to be competent in performing. These seven actions guided design of a Swimming RMT, which was subsequently conducted twice by 103 serving personnel (89 men, 11 women) and once by 65 recruits (49 men, 16 women). RESULTS: The RMT comprised of entering the water in combat fatigues and webbing, removing webbing, swimming 50 m, and staying afloat for up to 10 minutes. During RMT trials, in trial 1, 85% of serving personnel and 74% of recruits successfully completed the RMT, which increased to 93% in serving personnel for trial 2. Across trials 1 and 2, all three timed RMT elements showed moderate-high correlational reliability (ICC range: 0.462-0.791). On average, serving personnel were quicker to complete the 50 m swim phase compared to recruits (91±24 s vs. 100±26 s; U = 2575.0, rb = -0.192, p = 0.039). CONCLUSIONS: The JTA-informed Swimming RMT provides an assessment of the minimum role-related swimming/water competence standard for British Army personnel.

Evolution and irreversibility: Two distinct phenomena and their distinct laws of nature.

To clarify the place of time direction of change in nature (time arrow), the present article shows why Evolution and Irreversibility are two distinct phenomena. Their distinct laws of nature are the Constructal Law and the Second Law, respectively. The demonstration is based on the simplest setting imaginable: a solid body moving in a pool of water. The view is holistic: the system selected for analysis is the body and the pool, not the body alone, and the phenomenon is the evolution of the image (configuration) of the whole. New is also the answer to the question of what flows in this evolving flow configuration. Along the way, important terms are defined: phenomenon, law, irreversibility, nature, design, freedom, theory versus empiricism, information, knowledge, selection, purpose, engine, refrigeration, and wheel. More complex natural settings for the demonstration are in the second part of the article: engines, refrigeration, heating and cooling, the wheel, and a pushed boat sliding on water.

Risk Factors Associated with Urothelial Bladder Cancer.

BACKGROUND: Urothelial bladder carcinoma (UBC) is the most frequent histologic form of bladder cancer, constituting 90% of the cases. It is important to know the risk factors of UBC to avoid them and to decrease its recurrence after treatment. The aim of this review was to provide an overview of the risk factors associated with UBC incidence. METHODS: A comprehensive literature search from 2012 to 2024 was carried out in databases such as PubMed, Google Scholar, and Medline with potential keywords such as "bladder cancer", "urothelial bladder cancer", "incidence of urothelial bladder cancer worldwide", "mortality rate of bladder cancer", "incidence according to gender", "treatment for bladder cancer", and "risk factors of bladder cancer". Smoking tobacco was comprehended to be the major risk factor for UBC. Smoke from tobacco products contains polycyclic aromatic hydrocarbons (PAHs) and aromatic amines such as 4-aminobiphenyl, which are known to cause UBC. Smoking-related bladder cancer mortality ranks just second to smoking-related lung cancer mortality. For non-smokers, pollution became a major risk factor associated with UBC. Polycyclic aromatic hydrocarbons (PAHs) are linked to many cancers, especially to UBC. Indoor and outdoor pollution generates VOCs (volatile organic compounds) and PAHs. Small-particle matter < 2.5 is linked to UBC and lung cancers. Drinking chlorinated water is linked to UBC. Also, swimming in chlorinated pools that produce trihalomethanes increases the risk of many cancers, and especially of bladder cancer. Occupational exposure to carcinogens, specifically aromatic amines, is a significant UBC risk factor. It has been estimated that approximately 20% of all UBCs may be linked to this type of exposure, primarily in industrial settings that treat dye, paint, petroleum chemicals, and metal. The other risk factors included genetics, diet, and medical conditions. Alcohol, consumption of processed meat and whole milk, and higher intakes of selenium and vitamins A and E also contribute to the development of UBC. Further, chemotherapeutic agents, oral hypoglycemic drugs, and radiation therapy are positively associated with UBC. CONCLUSIONS: The significance of the initial prevention of UBC must be emphasized, and especially programs for quitting cigarettes should be encouraged and supported. However, smoking is not the only risk factor for UBC. For non-smokers, other risk factors should be investigated. Air and water pollution are linked to UBC. Indoor and outdoor pollution should be more controlled. Patients and people should be informed of the risk of drinking chlorinated water and swimming in chlorinated pools.

Validity of Current Smartwatches for Triathlon Training: How Accurate Are Heart Rate, Distance, and Swimming Readings?

Smartwatches are one of the most relevant fitness trends of the past two decades, and they collect increasing amounts of health and movement data. The accuracy of these data may be questionable and requires further investigation. Therefore, the aim of the present study is to validate smartwatches for use in triathlon training. Ten different smartwatches were tested for accuracy in measuring heart rates, distances (via global navigation satellite systems, GNSSs), swim stroke rates and the number of swim laps in a 50 m Olympic-size pool. The optical heart rate measurement function of each smartwatch was compared to that of a chest strap. Thirty participants (15 females, 15 males) ran five 3 min intervals on a motorised treadmill to evaluate the accuracy of the heart rate measurements. Moreover, for each smartwatch, running and cycling distance tracking was tested over six runs of 4000 m on a 400 m tartan stadium track, six hilly outdoor runs over 3.4 km, and four repetitions of a 36.8 km road bike course, respectively. Three swimming protocols ranging from 200 m to 400 m were performed in triplicate in a 50 m Olympic-size pool, evaluating the tracked distance and the detected number of strokes. The mean absolute percentage errors (MAPEs) for the average heart rate measurements varied between 3.1% and 8.3%, with the coefficient of determination ranging from 0.22 to 0.79. MAPE results ranged from 0.8% to 12.1% for the 4000 m run on the 400 m track, from 0.2% to 7.5% for the 3.4 km outdoor run, and from 0.0% to 4.2% for the 36.8 km bike ride. For the swimming tests, in contrast, the deviations from the true distance varied greatly, starting at a 0.0% MAPE for the 400 m freestyle and reaching 91.7% for the 200 m medley with style changes every 25 m. In summary, for some of the smartwatches, the measurement results deviated substantially from the true values. Measurements taken while road cycling over longer distances with only a few curves were in relative terms more accurate than those taken during outdoor runs and even more accurate than those taken on the 400 m track. In the swimming exercises, the accuracy of the measured distances was severely deteriorated by the medley changes among the majority of the smartwatches. Altogether, the results of this study should help in assessing the accuracy and thus the suitability of smartwatches for general triathlon training.