Stroke technique in C1 canoe slalom: a simulation study.

Male C1 canoe slalom athletes traditionally used cross transitions to move their paddle to the other side of the boat and off-side strokes to paddle on their non-dominant side. Conversely, female athletes often use a switching transition and on-side strokes on their non-dominant side. The purpose of this study was to use a computer model to assess the relation between cross- or switching techniques, and the relative strength (symmetry) of non-dominant compared to dominant side strokes to race times in C1 canoe slalom. We created a forward dynamics model to predict race times using stroke forces (from an indoor ergometer), drag forces (measured on-water), and probability distributions for stroke and transition times (measured from international canoe slalom competitions). The main effects from an ANOVA (p<0.05) were (i) for a given transition number and strength symmetry the race times were faster when using cross-transitions than switch-transitions (ii) for a given strength symmetry the race times became slower as the number of switch transitions increased, but there was minimal effect of the number of cross-transitions, and (iii) the closer the strength of the strokes were between the dominant and non-dominant side (as symmetry factor approached 100 %), the faster the race times.

Whitewater Waves.

The humanbecoming concept of powering is explored in this article with the author describing her experiences with whitewater waves on the Missouri River in South Dakota. The third principle of humanbecoming along with four humanbecoming inquiries on feeling sad, feeling unsure, feeling disrespected, and living hope are also presented in examining the paradoxical processes involved in powering.

Strength and strength-related anthropometric parameters of the international level canoe slalom male paddlers / Fuerza y parámetros antropométricos relacionados con la fuerza de los hombres remeros de canotaje slalom de nivel internacional

SUMMARY: The aim of the study was to determine the differences in hand-grip strength and strength-related anthropometric parameters between the highest-performance international paddlers (HILP) and other international paddlers (ILP) in canoe slalom. In male competitors (n=48; 23 canoeists and 25 kayakers) who took part in the 2018 European championship event in canoe slalom in Prague, Czech Republic representing 15 European countries were measured hand-grip strength and strength-related anthropometric parameters two days prior the event. Differences between the group of HILP (medallists from Olympic Games, world championship and European championship in the previous three years and European championship finalists at the same time) and ILP were found. HILP have significantly higher forearm, arm and chest girths than ILP. Moderate or high practical differences and margin statistic differences were found also for hand-grip strength, body weight, body mass index and age. The consistently high-performing paddlers are heavier, have more muscular upper body and are stronger than the other group, while keeping their lower body lean. Therefore, regular upper-body strength training to all canoe slalom paddlers is important but caution is required because body weight over 80 kg may be a limiting factor.

RESUMEN: El objetivo del estudio fue determinar las diferencias en la fuerza de prensión manual y los parámetros antropométricos relacionados con la fuerza entre los remeros internacionales de alto rendimiento (RIAR) y otros remeros internacionales de canotaje en slalom. En hombres competidores (n=48; 23 piragüistas y 25 kayakistas) que participaron en el campeonato europeo de slalom en canoa de 2018, en Praga, República Checa, que representa a 15 países europeos, se midió la fuerza de agarre manual y los parámetros antropométricos relacionados con la fuerza dos días antes del evento. Se encontraron diferencias entre el grupo de RIAR (medallistas de Juegos Olímpicos, campeonatos del mundo y campeonatos de Europa en los tres años anteriores y finalistas del campeonato de Europa al mismo tiempo) y remeros internacionales. Los RIAR presentaban circunferencias de antebrazo, brazo y pecho significativamente más altas que los remeros internacionales. Además, se encontraron diferencias prácticas moderadas o altas y diferencias estadísticas en el límite para la fuerza de prensión manual, el peso corporal, el índice de masa corporal y la edad. Los remeros de alto rendimiento son más pesados, tienen la parte superior del cuerpo más musculosa y son más fuertes que el otro grupo, mientras mantienen la parte inferior del cuerpo esbelta. Por lo tanto, es importante el entrenamiento regular de fuerza de la parte superior del cuerpo para todos los remeros de piragüismo, sin embargo se requiere precaución debido a que el peso corporal superior a 80 kg puede ser un factor limitante.

Prevention of external auditory canal exostosis in the Colorado whitewater community.

CONTEXT: External auditory canal exostoses (EACE) are bony formations that develop insidiously in the auditory meatus from chronic exposure to cold water and, in severe cases, require surgery. This condition has been understudied in the whitewater kayakers and not yet studied in the riverboarding population. Precautions such as earplugs are thought to prevent the formation of EACE because they mechanically block cold water from contacting the sensitive skin in the external auditory canal; however, earplugs are not commonly utilized by athletes. Inquiring about hobbies and the use of protective equipment can be done during osteopathic physicians' preventive care visits. OBJECTIVES: This article aims to determine the prevalence of EACE in Colorado whitewater athletes and their attitudes about wearing ear protection before and after an educational intervention directed at increasing awareness and prevention of EACE. METHODS: In July 2020, participants of this cross-sectional study completed a 10-min survey that collected demographics, whitewater experience, and perceptions of EACE, followed by an educational intervention. Participant ears were photographed utilizing a digital otoscope to assess EACE, and severity ratings were categorized into one of four occlusion levels: none (0%), mild (<25%), moderate (25-75%), or severe (>75%). Spearman correlation coefficients and Wilcoxon signed-rank tests were utilized to assess changes in attitudes before and after the educational intervention. RESULTS: Eighty-one participants (mean [SD] age = 36.3 [12.6] years, 25.9% female) completed the study: 74 kayakers and seven riverboarders. After the intervention, 60.5% (49/81) (p<0.001) reported greater understanding of EACE and 75.0% (60/80) were more likely to wear ear protection (p<0.001). Most (58.0%, 47/81) never wore ear protection. Of the 61 (75.0%) participants with at least one ear severity rating, most (55.7%, 34/61) had moderate EACE, 29.5% (18/61) had no to mild EACE, and 14.8% (9/61) had severe EACE (p<0.001). Impaired hearing was the biggest barrier to utilizing ear protection (51.6%, 33/64). CONCLUSIONS: Our results suggested that the educational intervention improved understanding of EACE and may increase utilization of ear protection in this population. Such prevention efforts may lead to better health of whitewater paddlers by reducing the incidence of EACE. Encouraging osteopathic physicians to inquire about hobbies and protective equipment during primary care preventive visits is essential to help keep athletes in the river doing what they love for longer, contributing to a healthier and happier whole person.

Isolation, Identification, and Selection of Bacteria With Proof-of-Concept for Bioaugmentation of Whitewater From Wood-Free Paper Mills.

In the wood-free paper industry, whitewater is usually a mixture of additives for paper production. We are currently lacking an efficient, cost-effective purification technology for their removal. In closed whitewater cycles the additives accumulate, causing adverse production problems, such as the formation of slime and pitch. The aim of our study was to find an effective bio-based strategy for whitewater treatment using a selection of indigenous bacterial isolates. We first obtained a large collection of bacterial isolates and then tested them individually by simple plate and spectrophotometric methods for their ability to degrade the papermaking additives, i.e., carbohydrates, resin acids, alkyl ketene dimers, polyvinyl alcohol, latex, and azo and fluorescent dyes. We examined correlation between carbon source use, genera, and inoculum source of isolates using two multivariate methods: principal component analysis and FreeViz projection. Of the 318 bacterial isolates, we selected a consortium of four strains (Xanthomonadales bacterium sp. CST37-CF, Sphingomonas sp. BLA14-CF, Cellulosimicrobium sp. AKD4-BF and Aeromonas sp. RES19-BTP) that degrade the entire spectrum of tested additives by means of dissolved organic carbon measurements. A proof-of-concept study on a pilot scale was then performed by immobilizing the artificial consortium of the four strains and inserting them into a 33-liter, tubular flow-through reactor with a retention time of < 15 h. The consortium caused an 88% reduction in the COD of the whitewater, even after 21 days.

Canoe slalom C1 stroke technique during international competitions.

The purpose of this study was to compare the frequency and duration of on-side and off-side strokes and stroke transitions between male and female canoe slalom athletes during international competitions. We analysed 33 International Canoe Federation World Cup, World Championship and European Canoe Association Championship canoe slalom race videos, from 2018 to 2020, frame-by-frame. We recorded drive durations and transition durations for each race run. We also recorded the frequency of different stroke types and transition types used in each run. Stroke timing parameters differed between female and male athletes. We found that female athletes performed a significantly greater proportion of switch transitions and on-side strokes. Male athletes performed a significantly greater proportion of cross transitions and off-side strokes. Male athletes performed significantly faster cross transitions. On-on and off-off transition durations were significantly faster than cross transitions, and cross transitions were significantly faster than switch transitions. Females had a significantly longer drive duration and lower stroke frequency compared to males. Overall, stroke and drive durations of on-side strokes and off-side strokes were not significantly different. This study identifies stroke technique differences between male and female canoe slalom athletes which can be used as a basis for future research and training.

Flush Drowning as a Cause of Whitewater Deaths.

INTRODUCTION: Most recreational whitewater fatalities are caused by fixed underwater entrapment or by "flush drowning," an obscure term frequently associated with high-volume rivers, continuous rapids, cold water, and a lack of prolonged underwater entrapment. Although entrapment drowning is typically associated with submersion hypoxia, flush drownings likely involve diverse mechanisms of death; as such, a concise definition is elusive. This said, certain risk factors may be predictively associated with flush drownings. We attempt to further characterize causes of fatal river accidents and possible effects of water temperature on injury pattern. METHODS: We reviewed river mortality data collected from the American Whitewater Association accident database comparing fatal whitewater accident trends in the Rocky Mountain region versus the Southeastern United States. We limited data from the Southeast to the months of June through August to create a warm water cohort. We then divided lethal accidents into flush drowning, entrapment submersion, or miscellaneous events, defining each category in specific terms. RESULTS: Flush drownings were more common in the Rocky Mountains than in the Southeast subgroup and involved older victims on average than entrapment drowning or miscellaneous events. Entrapment drownings were common in both regions, primarily occurring at fallen trees or rock formations. CONCLUSIONS: Flush drownings appear to occur more frequently in older persons. Although hypothetical, the relative increase in flush drowning in the Rocky Mountains might partly be the result of colder water temperatures. If the cause of flush drowning is better understood, safety in whitewater recreation may be improved.

Tolio: Foot Rot in Grand Canyon River Runners.

Treating skin disorders in wilderness settings is often challenging. In this report we describe common skin conditions affecting the feet of river runners on the Colorado River in Grand Canyon National Park. These conditions are frequently referred to by river runners with a catchall term, "tolio." Several skin disorders have been identified as components of tolio, with the most prevalent currently being pitted keratolysis. We present a case of pitted keratolysis in a river guide occurring during a multiday river trip, where treatment can be difficult. Prevention is often more important.

An Examination of Whitewater Boaters' Place Attachment and Specialization in Four Different River Settings.

Research on place attachment suggests that place identity and place dependence differ between recreationists with varying levels of specialization, recreating in different settings and with different resource proximities to their home. To further explore this relationship, we compared place attachment and recreation specialization of whitewater boaters in four different river settings. Data were collected on three rivers in the US and one in Austria. Place attachment was measured using four place identity and four place dependence items. Recreation specialization was treated as a multivariate construct consisting of the three dimensions; behavior, skill, and enduring involvement. The results of a cluster analysis revealed three specialization clusters. Two ANOVAs were performed by using place dependence and place identity as dependent variables and specialization clusters and the sampling rivers as independent variables. Place identity was not expressed differently between rivers but differed in specialization clusters. Place dependence was different between rivers but not between specialization clusters. Findings suggest that place attachment dimensions vary in river setting and specialization levels. Management should take into account that boaters exhibit different place attachment based on the specialization level and resource proximity to their home.

Whitewater Rafting and Kayaking Deaths in Colorado: Increasing Preventative Measures by Understanding Risk Factors.

INTRODUCTION: Whitewater rafting and kayaking are popular, adventurous excursions that are provided along various rivers throughout the United States. We expect that certain individuals' comorbid medical conditions may increase the risk of mortality by preventing them from being physically able to avoid inadvertently entering the water and subsequently rescue themselves. METHODS: Retrospective data were collected from 11 El Paso County, Colorado coroner cases from 2014-2017 in which the individual was whitewater rafting or kayaking and drowning was determined to be the primary cause of death. RESULTS: Health characteristics and autopsy findings of several of these individuals revealed that a significant number of these individuals were overweight or obese (90.9%), with 70% of these individuals also demonstrating cardiomegaly on examination. Of the cases studied, 81.8% of individuals had little to no experience with whitewater rafting or kayaking and 45% were under the influence of marijuana or alcohol based on toxicology studies. DISCUSSION: While a major selling point for whitewater excursions are the perceived risks they offer, our review suggests that certain individuals demonstrate increased health risks, have little to no experience with whitewater rafting or kayaking, or practice unsafe behaviors that may increase chance of injury and death. Efforts have been made to reduce risks associated with whitewater rafting and kayaking; however, further risk can be mitigated by excluding those who may be under the influence of alcohol or drugs, implementing more stringent health requirements, and setting an upper limit of difficulty of rapids based on an individual's previous experience.

Setting Preferences of High and Low Use River Recreationists: How Different are They?

Whitewater boaters often choose a river based on their preferences for attributes important for their trip experience. This study explored whether preferences and tradeoffs of whitewater boaters for social, resource, and managerial attributes of riverscapes differ among a high and a low use river in the United States by employing a stated choice approach. River trip scenarios were displayed using verbal descriptions and computer-generated photographs. Results indicate that use levels were more important for boaters on the low use river, whereas river difficulty and river access fee was of higher importance for the high use river boaters, who are more involved in this whitewater activity. Preferences for waiting times and trip length did not differ between the samples. Findings suggest that whitewater boaters of high and low use rivers have a different tradeoff behavior among river setting attributes, which has implications for river recreation management.

Leptospirosis presenting as honeymoon fever.

An increasing number of travelers from western countries visit tropical regions, questioning western physicians on the prophylaxis, the diagnosis and the therapeutic management of patients with travel-associated infection. In July 2014, a French couple stayed for an adventure-travel in Columbia without malaria prophylaxis. A week after their return the woman presented with fever, myalgia, and retro-orbital pain. Three days later, her husband presented similar symptoms. In both patients, testing for malaria, arboviruses and blood cultures remained negative. An empirical treatment with doxycycline and ceftriaxone was initiated for both patients. Serum collected from the female patient yielded positive IgM for leptospirosis but was negative for her husband. Positive Real-Time PCR were observed in blood and urine from both patients, confirming leptospirosis. Three lessons are noteworthy from this case report. First, after exclusion of malaria, as enteric fever, leptospirosis and rickettsial infection are the most prevalent travel-associated infections, empirical treatment with doxycycline and third generation cephalosporin should be considered. In addition, the diagnosis of leptospirosis requires both serology and PCR performed in both urine and blood samples. Finally, prophylaxis using doxycycline, also effective against leptospirosis, rickettsial infections or travellers' diarrhea should be recommended for adventure travelers in malaria endemic areas.

Injuries in commercial whitewater rafting on the New and Gauley rivers of West Virginia.

OBJECTIVE: To describe the rates, patterns, and likelihood of injuries in commercial whitewater rafting on the New and Gauley rivers, West Virginia. METHODS: Standardized injury report forms developed by the West Virginia Whitewater Commission were reviewed for years 2005-2010 to provide a statistical account of injuries reported by licensed commercial rafting outfitters operating on the New and Gauley rivers. RESULTS: Overall, musculoskeletal injuries (sprains/strains, 21.1%; dislocations, 13.8%; fractures, 12.2%) comprised the majority (47.4%) of incidents followed by injuries to soft tissue (lacerations, 29.0%; abrasions, 13.3%; contusions, 2.3%). Almost one half (44.3%) of injuries were to the head, neck, and shoulders followed by the lower extremities (foot/ankle/leg/knee/hip, 33.9%) and upper extremities (hand/wrist/arm, 14.3%). Data analyzed using the Somers' D statistic revealed the likelihood of an injury occurring inside the raft is P = .55, and P = .39 when passengers are ejected from the raft into the river. The most likely injuries to occur to passengers are a laceration (P = .51) or a sprain (P = .20). The main probabilities for the risks of injuries were found to be to the head (P = .24), shoulder (P = .16), and face (P = .13) of the passenger. CONCLUSIONS: By knowing what injuries are common, their likelihood of occurrence, and the settings in which they happen, commercial outfitters can initiate practices to reduce injury rates.