The purpose of the present study was to investigate the intra- and inter-individual variability in arm-leg coordination during the underwater phase of the turn segment in 200 m breaststroke. Thirteen male swimmers were recruited and performed a 200 m breaststroke in a pre-calibrated 25 m pool. Sub-phases during the underwater segment were obtained using a notational analysis, and the mean velocity, displacement and duration during each sub-phase were obtained. A hierarchical cluster analysis (HCA) was performed using the analysed variables in all phases to identify inter-individual variability and random intra-individual variability. In addition, a linear mixed model (LMM: lap as a fixed effect and the participant as a random effect) was conducted to investigate systematic intra-individual variability. HCA identified three coordination patterns that were distinguished by the timing of the dolphin kick relative to the arm pull-out and the duration of the glide with arms at the side. All swimmers except one performed the arm pull-out after the dolphin kick. Nine swimmers maintained one coordination pattern, but other swimmers switched their coordination during the trial, particularly by shortening the duration of the glide with arms at the side. LMM showed a linear decrease (from the first to the last turn) in the time gap between the end of the dolphin kick and the start of the arm pull-out (a glide with the streamlined body position; F = 9.64, p = 0.034) and the glide duration with the arms at the side (F = 11.66, p = 0.015). In conclusion, both inter- and intra-individual variabilities during the underwater phase were evident in 200 m breaststroke turns, which were categorised into three patterns based on the timing of the dolphin kick and the duration of glides.
- MeSH
- bérec * MeSH
- biomechanika MeSH
- lidé MeSH
- paže MeSH
- plavání * MeSH
- postura těla MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
In breaststroke races, the dolphin kick could finish before, at the same time, or during the arm pull-out, but it is unclear how swimmers perform this technique. The aim of this study was to investigate whether swimmers glide between the dolphin kick and arm pull-out, favour continuity or even overlap those two phases, as it would impact the active underwater sequence. Fourteen international and national male swimmers performed 100-m breaststroke with all-out effort in a pre-calibrated 25 m swimming pool. A multi-camera system tracked the head of the swimmers. Key points of the active underwater sequence were obtained from notational analysis. A hierarchical cluster analysis identified three coordination profiles. All swimmers started their dolphin kick before the arm pull-out. However, one swimmer started the arm pull-out before the end of the dolphin kick, seven swimmers started the arm pull-out after the end of the dolphin kick, and four swimmers synchronised the beginning of the arm pull-out and the end of the dolphin kick, while two other swimmers mixed two coordination profiles among the start and the three turns. Those different profiles allow achieving similar performance outcome, suggesting individual training regarding the underwater phase.
- Klíčová slova
- Coordination, biomechanics, cluster analysis, swimming, underwater sequence,
- MeSH
- bérec MeSH
- biomechanika MeSH
- lidé MeSH
- paže * MeSH
- plavání * MeSH
- shluková analýza MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
The monitoring of body mass (BM), plasma sodium concentration ([Na⁺]) and urinary specific gravity (Usg) are commonly used to help detect and prevent over- or dehydration in endurance athletes. We investigated pre-and post-race hydration status in 113 amateur 24-h ultra-runners, 100-km ultra-runners, multi-stage mountain bikers and 24-h mountain bikers, which drank ad libitum without any intervention and compared results of hyponatremic and non-hyponatremic finishers. On average, pre-race plasma [Na⁺] and both pre- and post-race levels of Usg and BM were not significantly different between both groups. However, nearly 86% of the post-race hyponatremic (exercise-associated hyponatremia, EAH) and 68% of the normonatremic (non-EAH) ultra-athletes probably drank prior the race greater volumes than their thirst dictated regarding to individual pre-race Usg levels. Fluid intake during the race was equal and was not related to plasma [Na⁺], Usg or BM changes. A significant decrease in post-race plasma [Na⁺], BM and an increasement in post-race Usg was observed in EAH and non-EAH finishers. Moreover, pre-race plasma [Na⁺] was inversely associated with post-race percentage change in plasma [Na⁺], and pre-race Usg and urinary [Na⁺] with percentage change in Usg in both groups with and without post-race EAH. Thirteen (11.5%) finishers developed post-race EAH (plasma [Na⁺] < 135 mM). The incidence of EAH in ultra-endurance athletes competing in the Czech Republic was higher than reported previously.
- MeSH
- běh * MeSH
- cyklistika * MeSH
- fyzická vytrvalost * MeSH
- hyponatremie epidemiologie metabolismus MeSH
- incidence MeSH
- lidé středního věku MeSH
- lidé MeSH
- pití MeSH
- sodík krev moč MeSH
- sportovci MeSH
- tělesná hmotnost MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika epidemiologie MeSH
- Názvy látek
- sodík MeSH
BACKGROUND: Exercise-associated hyponatremia (EAH), rhabdomyolysis and renal failure appear to be a unique problem in ultra-endurance racers. METHODS: We investigated the combined occurrence of EAH and rhabdomyolysis in seven different ultra-endurance races and disciplines (i.e. multi-stage mountain biking, 24-h mountain biking, 24-h ultra-running and 100-km ultra-running). RESULTS: Two (15.4%) ultra-runners (man and woman) from hyponatremic ultra-athletes (n = 13) and four (4%) ultra-runners (four men) from the normonatremic group (n = 100) showed rhabdomyolysis following elevated blood creatine kinase (CK) levels > 10,000 U/L without the development of renal failure and the necessity of a medical treatment. Post-race creatine kinase, plasma and urine creatinine significantly increased, while plasma [Na(+)] and creatine clearance decreased in hyponatremic and normonatremic athletes, respectively. The percentage increase of CK was higher in the hyponatremic compared to the normonatremic group (P < 0.05). Post-race CK levels were higher in ultra-runners compared to mountain bikers (P < 0.01), in faster normonatremic (P < 0.05) and older and more experienced hyponatremic ultra-athletes (P < 0.05). In all finishers, pre-race plasma [K(+)] was related to post-race CK (P < 0.05). CONCLUSIONS: Hyponatremic ultra-athletes tended to develop exercise-induced rhabdomyolysis more frequently than normonatremic ultra-athletes. Ultra-runners tended to develop rhabdomyolysis more frequently than mountain bikers. We found no association between post-race plasma [Na(+)] and CK concentration in both hypo- and normonatremic ultra-athletes.
- Klíčová slova
- Long distances, Mountain biking, Running,
- MeSH
- běh * MeSH
- cvičení * MeSH
- cyklistika * MeSH
- dospělí MeSH
- draslík krev MeSH
- hyponatremie krev moč MeSH
- index tělesné hmotnosti MeSH
- komorbidita MeSH
- kreatinin moč MeSH
- kreatinkinasa krev MeSH
- lidé středního věku MeSH
- lidé MeSH
- rhabdomyolýza krev moč MeSH
- sodík krev MeSH
- sportovci MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- draslík MeSH
- kreatinin MeSH
- kreatinkinasa MeSH
- sodík MeSH
We investigated seventy-four ultra-mountain bikers (MTBers) competing in the solo category in the first descriptive field study to detail nutrition habits and the most common food before during and after the 24 hour race using questionnaires. During the race, bananas (86.5%), energy bars (50.0%), apples (43.2%) and cheese (43.2%) were the most commonly consumed food, followed by bread (44.6%), rice (33.8%) and bananas (33.8%) after the race. Average fluid intake was 0.5 ± 0.2 l/h. The main beverage was isotonic sports drink (82.4%) during and pure water (66.2%) after the race. The most preferred four supplements in the four weeks before, the day before, during and after the race were vitamin C (35.1%), magnesium (44.6%), magnesium (43.2%) and branched-chain amino acids (24.3%), respectively. Total frequency of food intake (30.6 ± 10.5 times/24 hrs) was associated with fluid intake (r = 0.43, P = 0.04) and both were highest at the beginning of the race and lower during the night hours and the last race segment in a subgroup of twenty-three ultra-MTBers. Supplement intake frequency (6.8 ± 8.4 times/24 hrs) was highest during the night hours and lower at the beginning and end of the race. Elevated food and fluid intake among participants tracked across all race segments (P < 0.001). In conclusion, the nutrition strategy employed by ultra-MTBers was similar to those demonstrated in previous studies of ultra-cyclists with some exceptions among selected individuals.
- Klíčová slova
- 24-hour race, Race nutrition, Ultra-cycling,
- Publikační typ
- časopisecké články MeSH
BACKGROUND: The effects of running and cycling on changes in hydration status and body composition during a 24-hour race have been described previously, but data for 24-hour ultra-mountain bikers are missing. The present study investigated changes in foot volume, body composition, and hydration status in male and female 24-hour ultra-mountain bikers. METHODS: We compared in 49 (37 men and 12 women) 24-hour ultra-mountain bikers (ultra-MTBers) changes (Δ) in body mass (BM). Fat mass (FM), percent body fat (%BF) and skeletal muscle mass (SM) were estimated using anthropometric methods. Changes in total body water (TBW), extracellular fluid (ECF) and intracellular fluid (ICF) were determined using bioelectrical impedance and changes in foot volume using plethysmography. Haematocrit, plasma [Na+], plasma urea, plasma osmolality, urine urea, urine specific gravity and urine osmolality were measured in a subgroup of 25 ultra-MTBers (16 men and 9 women). RESULTS: In male 24-hour ultra-MTBers, BM (P < 0.001), FM (P < 0.001), %BF (P < 0.001) and ECF (P < 0.05) decreased whereas SM and TBW did not change (P > 0.05). A significant correlation was found between post-race BM and post-race FM (r = 0.63, P < 0.001). In female ultra-MTBers, BM (P < 0.05), %BF (P < 0.05) and FM (P < 0.001) decreased, whereas SM, ECF and TBW remained stable (P > 0.05). Absolute ranking in the race was related to Δ%BM (P < 0.001) and Δ%FM in men (P < 0.001) and to Δ%BM (P < 0.05) in women. In male ultra-MTBers, increased post-race plasma urea (P < 0.001) was negatively related to absolute ranking in the race, Δ%BM, post-race FM and Δ%ECF (P < 0.05). Foot volume remained stable in both sexes (P > 0.05). CONCLUSIONS: Male and female 24-hour ultra-MTBers experienced a significant loss in BM and FM, whereas SM remained stable. Body weight changes and increases in plasma urea do not reflect a change in body hydration status. No oedema of the lower limbs occurred.
- Publikační typ
- časopisecké články MeSH
BACKGROUND: To assess the prevalence of exercise-associated hyponatremia (EAH) in two 24-hour mountain bike (MTB) (R1,R2), one 24-hour running (R3) and one multi-stage MTB (R4) races held in the Czech Republic in a cluster of four cross-sectional studies. METHODS: In 27 ultra-mountain bikers (ultra-MTBers), 12 ultra-runners, and 14 multi-stage MTBers, fluid intake, changes (Δ) in body mass, hematocrit, plasma volume, plasma [Na+], plasma [K+], plasma osmolality, urine [Na+], urine [K+], urine specific gravity, urine osmolality, K+/Na+ ratio in urine, transtubular potassium gradient and glomerular filtration rate were measured and calculated. The use of non-steroidal anti-inflammatory drugs and symptoms of EAH were recorded using post-race questionnaires. RESULTS: Of the 53 finishers, three (5.7%) developed post-race EAH, thereof one (3.7%) ultra-MTBer, one (8.3%) ultra-runner and one (7.1%) multi-stage MTBer. Plasma [Na+] decreased significantly (p < 0.001) only in R4. Urine osmolality (R1, R3, R4 p < 0.001; R2 p < 0.05) and glomerular filtration rate (p < 0.001) increased, and body mass decreased in all races (p < 0.05). Δ body mass was inversely related to the number of kilometers achieved (p < 0.001) in R2 where better ultra-MTBers tended to lose more weight. Δ body mass (p < 0.001) and %Δ body mass (p = 0.05) were positively related to lower post-race plasma [Na+] in R3 that was associated with increased loss in body mass. Fluid intake was positively related to race performance in R1 and R2 (R1: p = 0.04; R2: p = 0.01) where ultra-MTBers in R1 and R2 who drank more finished ahead of those who drank less. Post-race plasma [Na+] was negatively associated with race performance in ultra-MTBers in R2 (p < 0.05), similarly ultra-runners in R3 (p < 0.05) where finishers with more kilometres had lower post-race plasma [Na+]. CONCLUSIONS: The prevalence of EAH in the Czech Republic was no higher compared to existing reports on ultra-endurance athletes in other countries. Lower plasma [Na+] and development of EAH may be attributed to overdrinking, a pituitary secretion of vasopressin, an impaired mobilization of osmotically inactive sodium stores, and/or an inappropriate inactivation of osmotically active sodium.
- Publikační typ
- časopisecké články MeSH
