Acute renal failure in four Comrades Marathon runners ingesting the same electrolyte supplement: Coincidence or causation?

Objectives. To evaluate common factors associated with the development of acute renal failure (ARF) in Comrades Marathon runners.Methods. This was a retrospective case series of 4 runners hospitalised post-race with ARF in the 89 km 2010 Comrades Marathon. The outcome measures were incidence of analgesic use, levels of creatine  phosphokinase (CPK) and degree of electrolyte supplementation (sodium, potassium, calcium and magnesium).Results. The prevalence of ARF was 1/4 125 runners. They presented with rhabdomyolysis (mean admission CPK of 36 294 IU) and hyponatraemia (mean admission blood sodium level of 133 mEq/l). All had ingested an analgesic during the run (3 ingested a non-steroidal anti-inflammatory  drug) and the same readily available anti-cramp electrolyte supplement.  The average amount of supplemental sodium (452 mg), potassium (393 mg), calcium (330 mg) and magnesium (154 mg) ingested via this  particular electrolyte supplement before and during the run did not exceedthe recommended upper limits of daily intake. Three of the runners were Comrades Marathon novices.Conclusions. There is a continuing need to clarify the specific cluster variants that cause ARF in Comrades Marathon runners, as the risk factors appear to have evolved since the first case was described over 40 years ago.S Afr Med J 2011;101:876-878

Avoid adding insult to injury – correct management of sick female endurance athletes

Objectives. To evaluate the efficacy of Ringer’s lactate, isotonic saline and hypertonic saline on the clinical and biochemical recovery of athletes with exercise-associated hyponatraemic encephalopathy caused by fluid overload.Methods. We retrospectively reviewed serial blood sodium concentrations (Na+) and qualitative signs of recovery and time to recovery in two healthy menstruant females hospitalised with dilutional exercise-associated hyponatraemic encephalopathy after withdrawal from the 2011 Comrades Marathon (89 km) and Argus Cycle Tour (109 km).Results. Improvements in blood Na+ did not occur with intravenous administration of Ringer’s lactate solution, but did occur with administration of isotonic and hypertonic saline. Qualitative improvements in mental status were not quantitatively related to the biochemical value of blood Na+ or subsequent return to normonatraemia.Conclusions. Hyponatraemia should be suspected in all female athletes presenting to the medical area of endurance races with vomiting, altered mental status and a history of high fluid intake. If a diagnosis of exercise-associated hyponatraemia with cerebral encephalopathy is confirmed, the treatment of choice is administration of an intravenous bolus of hypertonic saline. Administration of Ringer’s lactate should be discouraged, as this does not correct Na+ and appears to delay recovery

Drinking during marathon running in extreme heat: a video analysis study of the top finishers in the 2004 Athens Olympic marathons

Objective. To assess the drinking behaviours of top competitors during an Olympic marathon. Methods. Retrospective video analysis of the top four finishers in both the male and female 2004 Athens Olympic marathons plus the pre-race favourite in the female race in order to assess total time spent drinking. One male and female runner involved in a laboratory drinking simulation trial. Results. For the five female athletes, 37 of a possible 73 drinking episodes were captured. The female race winner was filmed at 11 of 15 drinking stations. Her total drinking time was 23.6 seconds; extrapolated over 15 seconds this would have increased to 32.2 seconds for a total of 27 sips of fluid during the race. Eighteen of a possible 60 drinking episodes for the top four male marathon finishers were filmed. The total drinking time for those 18 episodes was 11.4 seconds. A laboratory simulation found that a female athlete of approximately the same weight as the female Olympic winner might have been able to ingest a maximum of 810 ml (350 ml.h-1) from 27 sips whilst running at her best marathon pace whereas a male might have drunk a maximum of 720 ml (330 ml.h-1) from 9 sips under the same conditions. Conclusions. These data suggest that both the female and male 2004 Olympic Marathon winners drank minimal total amounts of fluid (<1 litre) in hot (>30ºC) temperatures while completing the marathon with race times within 2.5% of the Olympic record

Exercise-Associated hyponatremia: 2017 update

Exercise-associated hyponatremia (EAH) was initially described in the 1980s in endurance athletes, and work done since then has conclusively identified that overdrinking beyond thirst and non-osmotic arginine vasopressin release are the most common etiologic factors. In recent years, EAH has been described in a broader variety of athletic events and also has been linked to the development of rhabdomyolysis. The potential role of volume and sodium depletion in a subset of athletes has also been described. This review focuses on the most recent literature in the field of EAH and summarizes key new findings in the epidemiology, pathophysiology, treatment, and prevention of this condition

Fitness and body composition profiling of elite junior South African rugby players

Objective. The aim of this study was to describe the body composition, strength and speed characteristics of elite junior South African rugby players. Design. Cross-sectional. Setting. Field study. Subjects. Rugby players (16 and 18 years old, N = 174) selected for the South African Rugby Union National Green Squad. Outcome measures. Body composition, 10 m and 40 m speed, agility, 1RM bench press, underhand pull-ups, push-ups, multistage shuttle run. Results. The under-16 players were on average shorter (175.6 ± 5.7 v. 179.2 ± 6.7 cm), weighed less (76.5 ± 8.2 v. 84.8 ± 8.3 kg) had less upper body absolute strength (77.1 ± 11.8 kg v. 95.3 ± 16.7 kg) and muscular endurance (41 ± 12 v. 52 ± 15 push-ups) and aerobic fitness (87.1 ± 19.4 v. 93.5 ± 15.3 shuttles) than the under-18 players. There were no differences in body fat, sprinting speed (10 m and 40 m) or agility between the two age groups. There were differences between playing positions, with the props having the most body fat, strongest upper bodies, slowest sprinting speed, least agility and lowest aerobic capacity compared with players in the other positions. Conclusion. This study provides data for elite junior rugby players and can be used to monitor the progression of players after intervention while also assisting with talent identification for the different playing positions. South African Journal of Sports Medicine Vol. 18 (2) 2006: pp. 38-4

Fitness and body composition profiling of elite junior South African rugby players

Objective. The aim of this study was to describe the body composition, strength and speed characteristics of elite junior South African rugby players. Design. Cross-sectional. Setting. Field study. Subjects. Rugby players (16 and 18 years old, N = 174) selected for the South African Rugby Union National Green Squad. Outcome measures. Body composition, 10 m and 40 m speed, agility, 1RM bench press, underhand pull-ups, push-ups, multistage shuttle run. Results. The under-16 players were on average shorter (175.6 ± 5.7 v. 179.2 ± 6.7 cm), weighed less (76.5 ± 8.2 v. 84.8 ± 8.3 kg) had less upper body absolute strength (77.1 ± 11.8 kg v. 95.3 ± 16.7 kg) and muscular endurance (41 ± 12 v. 52 ± 15 push-ups) and aerobic fitness (87.1 ± 19.4 v. 93.5 ± 15.3 shuttles) than the under-18 players. There were no differences in body fat, sprinting speed (10 m and 40 m) or agility between the two age groups. There were differences between playing positions, with the props having the most body fat, strongest upper bodies, slowest sprinting speed, least agility and lowest aerobic capacity compared with players in the other positions. Conclusion. This study provides data for elite junior rugby players and can be used to monitor the progression of players after intervention while also assisting with talent identification for the different playing positions

Perceived exertion influences pacing among ultramarathon runners but post-race mood change is associated with performance expectancy

Objectives. This study investigated whether post-race mood changes among ultramarathon runners are associated with perceived exertion or the discrepancy between their actual and predicted performance times.Methods. Eight runners completed the Puffer ultramarathon, which is a challenging 73 km mountainous race across Table Mountain National Park in South Africa. Each runner completed a series of profile of mood state questionnaires (POMS) 2 days before the race (baseline), on the morning of the race (pre-race) and immediately after the race (post-race). Ratings of perceived exertion (RPE) were measured at 13 points during the race using the Borg 6-20 scale. The accuracy of performance expectationswas measured as the difference between runners’ actual and predicted race times.Results. Average completion time was 11:31:36±00:26:32 (h :mm:ss), average running speed was 6.4±2.2 km.hr-1 and averageRPE was 14.1±2.0. Increased POMS confusion was found before the race (33.30.7 v. 37.1±5.2, p=0.014; baseline v. pre-race). Post-race increases in POMS total mood disturbance (TMD) were found (168.3±20 v. 137.5±6.3, p=0.001; post race v. baseline) characterised by decreased vigour (43.3±4.0 v. 33.5±7.0, p=0.008; baseline v. post race), increased confusion (33.3±0.7 v. 38.5±4.8, p=0.006; baseline v. post race) and increased fatigue (37.8±4.8 v. 53.8±7.3, p=0.0003; baseline v. post race). A linear increase in RPE was found during the race (r=0.737, p=0.002).The magnitude of their post-race mood change (r=-0.704, p=0.026) was not found to be associated with runners’ average RPE but was found to be negatively correlated with accuracy of the performance predictions. A time series analysis indicated that POMS TMD would have taken 142±89 min to recover. Conclusions. The results show that RPE influences the wayultramarathon runners pace themselves more than performance expectancy but performance expectations have a greater influence on post-race mood. The magnitude of post-race mood change is associated with the extent of discrepancy between runners’ predicted and actual performance. This has implications for designing appropriate goals and pacing strategies for ultraendurance athletes.

Fitness and body composition profiling of elite junior South African rugby players

Objective. The aim of this study was to describe the body composition, strength and speed characteristics of elite junior South African rugby players. Design. Cross-sectional. Setting. Field study. Subjects. Rugby players (16 and 18 years old, N = 174) selected for the South African Rugby Union National Green Squad. Outcome measures. Body composition, 10 m and 40 m speed, agility, 1RM bench press, underhand pull-ups, push-ups, multistage shuttle run. Results. The under-16 players were on average shorter (175.6 ± 5.7 v. 179.2 ± 6.7 cm), weighed less (76.5 ± 8.2 v. 84.8 ± 8.3 kg) had less upper body absolute strength (77.1 ± 11.8 kg v. 95.3 ± 16.7 kg) and muscular endurance (41 ± 12 v. 52 ± 15 push-ups) and aerobic fitness (87.1 ± 19.4 v. 93.5 ± 15.3 shuttles) than the under-18 players. There were no differences in body fat, sprinting speed (10 m and 40 m) or agility between the two age groups. There were differences between playing positions, with the props having the most body fat, strongest upper bodies, slowest sprinting speed, least agility and lowest aerobic capacity compared with players in the other positions. Conclusion. This study provides data for elite junior rugby players and can be used to monitor the progression of players after intervention while also assisting with talent identification for the different playing positions. South African Journal of Sports Medicine Vol. 18 (2) 2006: pp. 38-4

Water and sodium intake habits and status of ultra-endurance runners during a multi-stage ultra-marathon conducted in a hot ambient environment: an observational field based study

<p>Abstract</p> <p>Background</p> <p>Anecdotal evidence suggests ultra-runners may not be consuming sufficient water through foods and fluids to maintenance euhydration, and present sub-optimal sodium intakes, throughout multi-stage ultra-marathon (MSUM) competitions in the heat. Subsequently, the aims were primarily to assess water and sodium intake habits of recreational ultra-runners during a five stage 225 km semi self-sufficient MSUM conducted in a hot ambient environment (T_max range: 32°C to 40°C); simultaneously to monitor serum sodium concentration, and hydration status using multiple hydration assessment techniques.</p> <p>Methods</p> <p>Total daily, pre-stage, during running, and post-stage water and sodium ingestion of ultra-endurance runners (UER, <it>n</it> = 74) and control (CON, <it>n</it> = 12) through foods and fluids were recorded on Stages 1 to 4 by trained dietetic researchers using dietary recall interview technique, and analysed through dietary analysis software. Body mass (BM), hydration status, and serum sodium concentration were determined pre- and post-Stages 1 to 5.</p> <p>Results</p> <p>Water (overall mean (SD): total daily 7.7 (1.5) L/day, during running 732 (183) ml/h) and sodium (total daily 3.9 (1.3) g/day, during running 270 (151) mg/L) ingestion did not differ between stages in UER (<it>p</it> < 0.001 <it>vs</it>. CON). Exercise-induced BM loss was 2.4 (1.2)% (<it>p</it> < 0.001). Pre- to post-stage BM gains were observed in 26% of UER along competition. Pre- and post-stage plasma osmolality remained within normal clinical reference range (280 to 303 mOsmol/kg) in the majority of UER (<it>p</it> > 0.05 <it>vs</it>. CON pre-stage). Asymptomatic hyponatraemia (<135 mmol/L) was evident pre- and post-stage in <it>n</it> = 8 UER, corresponding to 42% of sampled participants. Pre- and post-stage urine colour, urine osmolality and urine/plasma osmolality ratio increased (<it>p</it> < 0.001) as competition progressed in UER, with no change in CON. Plasma volume and extra-cellular water increased (<it>p</it> < 0.001) 22.8% and 9.2%, respectively, from pre-Stage 1 to 5 in UER, with no change in CON.</p> <p>Conclusion</p> <p>Water intake habits of ultra-runners during MSUM conducted in hot ambient conditions appear to be sufficient to maintain baseline euhydration levels. However, fluid over-consumption behaviours were evident along competition, irrespective of running speed and gender. Normonatraemia was observed in the majority of ultra-runners throughout MSUM, despite sodium ingestion under benchmark recommendations.</p

Nutrition Strategies for Triathlon

Contemporary sports nutrition guidelines recommend that each athlete develop a personalised, periodised and practical approach to eating that allows him or her to train hard, recover and adapt optimally, stay free of illness and injury and compete at their best at peak races. Competitive triathletes undertake a heavy training programme to prepare for three different sports while undertaking races varying in duration from 20 min to 10 h. The everyday diet should be adequate in energy availability, provide CHO in varying amounts and timing around workouts according to the benefits of training with low or high CHO availability and spread high-quality protein over the day to maximise the adaptive response to each session. Race nutrition requires a targeted and well-practised plan that maintains fuel and hydration goals over the duration of the specific event, according to the opportunities provided by the race and other challenges, such as a hot environment. Supplements and sports foods can make a small contribution to a sports nutrition plan, when medical supplements are used under supervision to prevent/treat nutrient deficiencies (e.g. iron or vitamin D) or when sports foods provide a convenient source of nutrients when it is impractical to eat whole foods. Finally, a few evidence-based performance supplements may contribute to optimal race performance when used according to best practice protocols to suit the triathlete’s goals and individual responsiveness