Does the Menstrual Cycle Influence Aerobic Capacity in Endurance-Trained Women?

Purpose: The aim was to study if aerobic capacity varies during different phases of the menstrual cycle (MC) in endurance-trained female athletes. Methods: Ten endurance-trained eumenorrheic women performed a submaximal test followed by an incremental test until exhaustion three times during one MC, early follicular phase (EFP), late follicular phase (LFP), and midluteal phase (MLP). During the submaximal test, the respiratory exchange ratio (RER) and utilization of fat and carbohydrates were analyzed; and, during the incremental test, VO2 peak, maximal heart rate, utilization of fat and carbohydrates, and RER were analyzed. Lactate levels were analyzed at rest, during the submaximal test, and after the incremental test. The anaerobic threshold was determined at RER = 1. Results: No significant differences (p < .05) between the MC phases were seen in a maximal heart rate or VO2peak. Similarly, VO2, heart rate, RER, fatty acid oxidation, and carbohydrate oxidation at 70, 80, 90, and 100% of VO2peak did not differ significantly between MC phases. There were no significant differences between these phases in resting lactate before the test or during the submaximal tests, though there was a significant difference in lactate concentration 3 minutes after the incremental test between the EFP and the LFP (p = .043). Conclusion: This study did not display variations in physiological parameters between EFP, LFP, and MLP, indicating similar aerobic capacity despite hormonal variations. This knowledge may be useful when planning for competition in aerobic events.

Effects of a 20-Week High-Intensity Strength Training Program on Muscle Strength Gain and Cardiac Adaptation in Untrained Men: Preliminary Results of a Prospective Longitudinal Study.

BACKGROUND: As strength sports gain popularity, there is a growing need to explore the impact of sustained strength training on cardiac biventricular structure and function, an area that has received less attention compared to the well-established physiological cardiac adaptation to endurance training. OBJECTIVE: This study aims to implement a 20-week high-intensity strength training program to enhance maximal muscle strength and evaluate its impact on cardiac biventricular adaptation in healthy, untrained men. METHODS: A total of 27 healthy and untrained young men (mean age 22.8, SD 3.2 years) participated in a strength training program designed to increase muscle strength. The training program involved concentric, eccentric, and isometric exercise phases, conducted over a consecutive 20-week time frame with a frequency of 3 weekly training sessions. Participants were evaluated before and after 12 and 20 weeks of training through body composition analysis (bioelectrical impedance), a 12-lead resting electrocardiogram, 3D transthoracic echocardiography, cardiopulmonary exercise testing, and muscle isokinetic dynamometry. The progression of strength training loads was guided by 1-repetition maximum (RM) testing during the training program. RESULTS: Of the initial cohort, 22 participants completed the study protocol. No injuries were reported. The BMI (mean 69.8, SD 10.8 kg/m² vs mean 72, SD 11 kg/m²; P=.72) and the fat mass (mean 15.3%, SD 7.5% vs mean 16.5%, SD 7%; P=.87) remained unchanged after training. The strength training program led to significant gains in 1-RM exercise testing as early as 4 weeks into training for leg extension (mean 69.6, SD 17.7 kg vs mean 96.5, SD 31 kg; P<.001), leg curl (mean 43.2, SD 9.7 kg vs mean 52.8, SD 13.4 kg; P<.001), inclined press (mean 174.1, SD 41.1 kg vs mean 229.2, SD 50.4 kg; P<.001), butterfly (mean 26.3, SD 6.2 kg vs mean 32.5, SD 6.6 kg; P<.001), and curl biceps on desk (mean 22.9, SD 5.2 kg vs mean 29.6, SD 5.2 kg; P<.001). After 20 weeks, the 1-RM leg curl, bench press, pullover, butterfly, leg extension, curl biceps on desk, and inclined press showed significant mean percentage gains of +40%, +41.1%, +50.3%, +63.5%, +80.1%, +105%, and +106%, respectively (P<.001). Additionally, the isokinetic evaluation confirmed increases in maximal strength for the biceps (+9.2 Nm), triceps (+11.6 Nm), quadriceps (+46.8 Nm), and hamstrings (+25.3 Nm). In this paper, only the training and muscular aspects are presented; the cardiac analysis will be addressed separately. CONCLUSIONS: This study demonstrated that a short-term high-intensity strength training program was successful in achieving significant gains in muscle strength among previously untrained young men. We intend to use this protocol to gain a better understanding of the impact of high-intensity strength training on cardiac physiological remodeling, thereby providing new insights into the cardiac global response in strength athletes. TRIAL REGISTRATION: ClinicalTrials.gov NCT04187170; https://clinicaltrials.gov/study/NCT04187170.

Diagnosis and management of children with McArdle Syndrome (GSD V) in New South Wales.

Glycogen storage type V (GSD V-McArdle Syndrome) is a rare neuromuscular disorder characterised by severe pain early after the onset of physical activity. A recent series indicated a diagnostic delay of 29 years; hence reports of children affected by the disorder are uncommon (Lucia et al., 2021, Neuromuscul Disord, 31, 1296-1310). This paper presents eight patients with a median onset age of 5.5 years and diagnosis of 9.5 years. Six patients had episodes of rhabdomyolysis with creatine kinase elevations >50 000 IU/L. Most episodes occurred in relation to eccentric non-predicted activities rather than regular exercise. One of the patients performed a non-ischaemic forearm test. One patient was diagnosed subsequent to a skeletal muscle biopsy, and all had confirmatory molecular genetic diagnosis. Three were homozygous for the common PYGM:c.148C > T (p.Arg50*) variant. All but one patient had truncating variants. All patients were managed with structured exercise testing to help them identify 'second-wind', and plan an exercise regimen. In addition all also had an exercise test with 25 g maltodextrin which had statistically significant effect on ameliorating ratings of perceived exertion. GSD V is under-recognised in paediatric practice. Genetic testing can readily diagnose the condition. Careful identification of second-wind symptomatology during exercise with the assistance of a multi-disciplinary team, allows children to manage activities and tolerate exercise. Maltodextrin can be used for structured exercise, but excessive utilisation may lead to weight gain. Early intervention and education may improve outcomes into adult life.

Nutrition and Hydration for High-Altitude Alpinism: A Narrative Review.

This report aims to summarise the scientific knowledge around hydration, nutrition, and metabolism at high altitudes and to transfer it into the practical context of extreme altitude alpinism, which, as far as we know, has never been considered before in the literature. Maintaining energy balance during alpine expeditions is difficult for several reasons and requires a deep understanding of human physiology and the biological basis for altitude acclimation. However, in these harsh conditions it is difficult to reconcile our current scientific knowledge in sports nutrition or even for mountaineering to high-altitude alpinism: extreme hypoxia, cold, and the logistical difficulties intrinsic to these kinds of expeditions are not considered in the current literature. Requirements for the different stages of an expedition vary dramatically with increasing altitude, so recommendations must differentiate whether the alpinist is at base camp, at high-altitude camps, or attempting the summit. This paper highlights nutritional recommendations regarding prioritising carbohydrates as a source of energy and trying to maintain a protein balance with a practical contextualisation in the extreme altitude environment in the different stages of an alpine expedition. More research is needed regarding specific macro and micronutrient requirements as well as the adequacy of nutritional supplementations at high altitudes.

Heart rate, oxygen uptake, and energy expenditure response of an SL3 class parabadminton athlete to a progressive test and simulated training session: a case study.

This investigation demonstrated a routine of evaluation and training of an athlete of the SL3 class of parabadminton for 2 days continuously monitored by a metabolic analyzer with measurements of oxygen consumption (V̇O2), carbon dioxide production, and heart rate (HR). The results showed HR and V̇O2 responses varying between 50% and 99.54% of HRmax (mean HR 80.92 bpm), and 6% and 104% (mean V̇O2 35.25 mL/kg/min) of V̇O2max, during the simulated game. The exercise test and the simulated training session showed significant changes in HR and V̇O2, reinforcing the need for considerable energy input to training and assessment.

Study of the Kinetics of the Determinants of Performance During a Mountain Ultramarathon: Multidisciplinary Protocol of the First Trail Scientifique de Clécy 2021.

BACKGROUND: The growing interest of the scientific community in trail running has highlighted the acute effects of practice at the time of these races on isolated aspects of physiological and structural systems; biological, physiological, cognitive, and muscular functions; and the psychological state of athletes. However, no integrative study has been conducted under these conditions with so many participants and monitoring of pre-, per-, and postrace variables for up to 10 days over a distance close to 100 miles. OBJECTIVE: The aim of this study was to evaluate the kinetics of the performance parameters during a 156 km trail run and 6000 m of elevation gain in pre-, per-, and postrace conditions. The general hypothesis is based on significant alterations in the psychological, physiological, mechanical, biological, and cognitive parameters. METHODS: The Trail Scientifique de Clécy took place on November 11, 2021. This prospective experimental study provides a comprehensive exploration of the constraints and adaptations of psychophysiological and sociological variables assessed in real race conditions during a trail running of 156 km on hilly ground and 6000 m of elevation gain (D+). The study protocol allowed for repeatability of study measurements under the same experimental conditions during the race, with the race being divided into 6 identical loops of 26 km and 1000 m D+. Measurements were conducted the day before and the morning of the race, at the end of each lap, after a pit stop, and up to 10 days after the race. A total of 55 participants were included, 43 (78%) men and 12 (22%) women, who were experienced in ultra-trail-running events and with no contraindications to the practice of this sport. RESULTS: The launch of the study was authorized on October 26, 2021, under the trial number 21-0166 after a favorable opinion from the Comité de Protection des Personnes Ouest III (21.09.61/SIRIPH 2G 21.01586.000009). Of the 55 runners enrolled, 41 (75%) completed the race and 14 (25%) dropped out for various reasons, including gastric problems, hypothermia, fatigue, and musculoskeletal injuries. All the measurements for each team were completed in full. The race times (ie, excluding the measurements) ranged from 17.8206 hours for the first runner to 35.9225 hours for the last runner. The average time to complete all measurements for each lap was 64 (SD 3) minutes. CONCLUSIONS: The Trail Scientifique de Clécy, by its protocol, allowed for a multidisciplinary approach to the discipline. This approach will allow for the explanation of the studied parameters in relation to each other and observation of the systems of dependence and independence. The initial results are expected in June 2022. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/38027.

The Performance, Physiology and Morphology of Female and Male Olympic-Distance Triathletes.

Sex differences in triathlon performance have been decreasing in recent decades and little information is available to explain it. Thirty-nine male and eighteen female amateur triathletes were evaluated for fat mass, lean mass, maximal oxygen uptake (VO2 max), ventilatory threshold (VT), respiratory compensation point (RCP), and performance in a national Olympic triathlon race. Female athletes presented higher fat mass (p = 0.02, d = 0.84, power = 0.78) and lower lean mass (p < 0.01, d = 3.11, power = 0.99). VO2 max (p < 0.01, d = 1.46, power = 0.99), maximal aerobic velocity (MAV) (p < 0.01, d = 2.05, power = 0.99), velocities in VT (p < 0.01, d = 1.26, power = 0.97), and RCP (p < 0.01, d = 1.53, power = 0.99) were significantly worse in the female group. VT (%VO2 max) (p = 0.012, d = 0.73, power = 0.58) and RCP (%VO2 max) (p = 0.005, d = 0.85, power = 0.89) were higher in the female group. Female athletes presented lower VO2 max value, lower lean mass, and higher fat mass. However, females presented higher values of aerobic endurance (%VO2 max), which can attenuate sex differences in triathlon performance. Coaches and athletes should consider that female athletes can maintain a higher percentage of MAV values than males during the running split to prescribe individual training.

Physiological Responses and Predictors of Performance in a Simulated Competitive Ski Mountaineering Race.

Competitive ski mountaineering (SKIMO) has achieved great popularity within the past years. However, knowledge about the predictors of performance and physiological response to SKIMO racing is limited. Therefore, 21 male SKIMO athletes split into two performance groups (elite: VO2max 71.2 ± 6.8 ml· min-1· kg-1 vs. sub-elite: 62.5 ± 4.7 ml· min-1· kg-1) were tested and analysed during a vertical SKIMO race simulation (523 m elevation gain) and in a laboratory SKIMO specific ramp test. In both cases, oxygen consumption (VO2), heart rate (HR), blood lactate and cycle characteristics were measured. During the race simulation, the elite athletes were approximately 5 min faster compared with the sub-elite (27:15 ± 1:16 min; 32:31 ± 2:13 min; p < 0.001). VO2 was higher for elite athletes during the race simulation (p = 0.046) and in the laboratory test at ventilatory threshold 2 (p = 0.005) and at maximum VO2 (p = 0.003). Laboratory maximum power output is displayed as treadmill speed and was higher for elite than sub-elite athletes (7.4 ± 0.3 km h-1; 6.6 ± 0.3 km h-1; p < 0.001). Lactate values were higher in the laboratory maximum ramp test than in the race simulation (p < 0.001). Pearson's correlation coefficient between race time and performance parameters was highest for velocity and VO2 related parameters during the laboratory test (r > 0.6). Elite athletes showed their superiority in the race simulation as well as during the maximum ramp test. While HR analysis revealed a similar strain to both cohorts in both tests, the superiority can be explainable by higher VO2 and power output. To further push the performance of SKIMO athletes, the development of named factors like power output at maximum and ventilatory threshold 2 seems crucial.

Previous experience, aerobic capacity and body composition are the best predictors for Olympic distance triathlon performance: Predictors in amateur triathlon.

OBJECTIVE: Present study examines predictors of the overall race time and disciplines in the Olympic distance triathlon. METHODS: Thirty-nine male and six female triathletes were evaluated for anthropometric, physiological, genetic, training, clinical and circadian characteristics. Body composition, maximum capacity for oxygen uptake (V˙O2max), maximum aerobic velocity (MAV), anaerobic threshold (AT), triathlon experience (TE) and XX genotype for α-actinin 3 affected total race time (p<0.05). RESULTS: Total race time can be predicted by MAV (ß = -0.430, t = -3.225, p = 0.003), TE (ß = -0.378, t = -3.605, p = 0.001), and percentage of lean mass (%LM) (ß = -0.332, t = -2.503, p = 0.017). Swimming can be predicted by MAV (ß = -0.403, t = -3.239, p = 0.002), TE (ß = -0.339, t = -2.876, p = 0.007), and AT%V˙O2max (ß = 0.281, t = 2.278, p = 0.028). Cycling can be predicted by MAV (ß = -0.341, t = -2.333, p = 0.025), TE (ß = -0.363, t = -3.172, p = 0.003), and %LM (ß = -0.326, t = -2.265, p = 0.029). In running split, MAV (ß = -0.768, t = -6.222, p < 0.001) was the only parameter present in the best multiple linear regression model. CONCLUSION: The most important variables in multiple regression models for estimating performance were MAV, TE, AT and %LM.

A Review of Players' Characterization and Game Performance on Male Rink-Hockey.

The aim of this study was to review the evolutionary tendencies of research regarding to the study of male Rink-Hockey players´ and game performance. A systematic search was conducted in PubMed, Web of Knowledge and Scopus databases according to PRISMA method. The initial search identified 815 titles, resulting in 19 articles being included within the review. Original papers (English language) contained relevant data regarding rink hockey players' performance or morphological/physiological demands, anthropometry/body composition characteristics were eligible. Studies were classified into categories: (1) Physiological Demands, (2) Anthropometry and Body Composition, (3) Game Characterization/Patterns, (4) Injuries. Results indicated that Rink hockey requires high intensity effort which demands both short and long duration efforts requirements from players. Body composition analysis shows to be an important monitoring tool which complements the understanding of the athlete's cardiac adaptation. Game patterns shows a combination of specific game momentums with different outcomes according to the game zone. The intense short-term movements, collision and contact between players, in addition to the weight and speed of the hard ball and the stick, can considerably increase the risk of moderate and severe injuries. Lack of literature in Rink-Hockey is remarkable, and research is mainly focused on children and adolescents' players. Furthermore, the existing research with adult elite athletes was assessed with a small sample size.

Conditioning equine athletes on water treadmills significantly improves peak oxygen consumption.

Equine water treadmills (WT) were initially designed for rehabilitation of musculoskeletal injuries, but are also commonly used for conditioning sport horses, however the effects are not well documented. The purpose of this study was to test the effect of an 18-day WT conditioning programme on peak oxygen consumption (V̇O2peak). Nine unfit Thoroughbreds were used in a randomised controlled trial. Six horses worked daily for 18 days in stifle-height water (WT group), while 3 control horses worked without water (dry treadmill group (DT)). Preconditioning and postconditioning maximal exercise racetrack tests (800 m) were performed using a portable ergospirometry system. Measured outcomes were V̇O2, tidal volume, minute ventilation, breathing frequency, heart rate, blood lactate and instantaneous and average speed. The workload as assessed by V̇O2 was 21.7 per cent of preconditioning V̇O2peak values for WT horses. V̇O2peak on the racetrack increased by 16.1 per cent from preconditioning to postconditioning in the WT horses (P=0.03), but did not change in the DT horses. Therefore, exercising horses in high water heights may improve conditioning.

Sudden Cardiac Death in Sports: Why Its Prevalence is So Different by Gender?

Sports competition can be a trigger to fatal arrhythmias in predisposed individuals, leading to sudden cardiac death. Athletes have 2.8 fold more risk of sudden cardiac death than non-athletes. However, female athletes seem to have some cardiac protection, dying suddenly much less than men during sports. Although the mechanisms for this protection have not been well established until now, hormonal, genetic and molecular factors may play a role in it. The so-called "fair sex" might harbour the key for sudden cardiac death prevention

Time-motion analysis of competitive surfers: Portuguese championship

SUMMARY BACKGROUND: Time-motion analysis has been used to provide detailed insight into surfers' performance. This study evaluated surfers' activity times at the Portuguese surfing championship in order to account for the time spent in each surfing activity. METHODS: Eighty-seven individually recorded videos of surfers were analyzed, showing their activity over the entire heat, and video analysis software was used to obtain each surfer's activity profile in the competition. RESULTS: The results breakdown by time percentage show that the surfers were paddling 50.9% of the time, sprint paddling for wave 1.9%, were stationary 34.1% of the time, wave riding 3.7%, and involved in miscellaneous activities (e.g., duck diving, board recovery, etc.) 9.4% of the total time. Average times spent in each surfing activity were 18.6 seconds for paddling, 2.9 seconds for sprint paddling for a wave, 21.7 seconds for the stationary period, 11.5 seconds for wave riding, and 6.9 seconds for miscellaneous activities. CONCLUSIONS: The data revealed that the most performed heat activity was paddling, allowing us to conclude that surfing is basically a long-arm paddling activity and that this activity constitutes a specific surfing competition demand, which in turn means that individual surfer's data can be used as a starting point for the development of tailored conditioning training programs.

RESUMO INTRODUÇÃO: A análise temporal dos movimentos tem sido usada para fornecer informações detalhadas sobre o desempenho dos surfistas. O objetivo deste estudo foi avaliar os tempos das atividades dos surfistas em um campeonato português de surfe, em nível nacional, a fim de contabilizar o tempo gasto em cada movimento do surfe. MÉTODOS: Foram realizadas 87 filmagens individuais dos surfistas, durante os diversos heats que decorreram ao longo da competição, sendo estas analisadas com um software para obtenção do perfil das atividades dos surfistas na competição. RESULTADOS: Os dados obtidos revelaram que o movimento de remada correspondeu a 50,9% do tempo total despendido na competição, a remada para apanhar a onda consistiu em 1,9%, o período estacionário compreendeu 34,1%, o ato de apanhar a onda de apenas 3,7% e outras atividades (bico de pato, recuperação da prancha etc.) envolveram 9,4% do tempo total da competição. Os tempos médios gastos em cada atividade de surfe foram de 18,6 segundos para remada, 2,9 segundos para remada para apanhar a onda, 21,7 segundos para o período estacionário, 11,5 segundos para andar de onda e 6,9 segundos para outras atividades. CONCLUSÕES: Os resultados revelaram que o surfe consiste em uma atividade que abrange longos períodos de remada, envolvendo uma demanda energética específica para a prática desse esporte. Os dados obtidos são necessários para o desenvolvimento de estratégias de treinamento que levem em consideração o tempo gasto em cada atividade do surfe e o consequente metabolismo energético envolvido, a fim de que se efetive uma prescrição adequada de um programa de treinamento.

Relationships between Different Field Test Performance Measures in Elite Goalball Players.

Goalball is a Paralympic sport involving people with visual impairment. Little is known about the physical fitness of elite players of this sport, as previous studies only evaluated body composition and aerobic capacity. Thus, the aim of this study was to describe the performance of elite goalball players in different physical tests and to look for relationships between them. Eleven elite Brazilian goalball players, seven males and four females, were evaluated for body composition, maximal handgrip isometric force (MHGF), countermovement jump (CMJ), throwing velocity (TV) and the Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1). Players produced 41.54 ± 8.41 kgf in MHGF, 34.81 ± 7.2 cm in CMJ, 14.21 ± 1.89 m∙s-1 in TV, and 505 ± 313 m in Yo-Yo IR1, with an estimated maximum oxygen consumption (VO2max) of 40.64 ± 2.63 mL∙kg-1∙min-1. Most performance tests exhibited moderate to high correlations among them, while the percentage of body fat correlated with both the CMJ and Yo-Yo IR1 results. The current study reveals that CMJ could be a valuable monitoring tool as it was correlated with all other performance tests. The highest correlation observed was with TV (r = 0.754; p < 0.05), which is a key capacity in goalball. Moreover, high levels of body fat could be detrimental to anaerobic performance.

As diferentes fases do ciclo menstrual não influenciam o rendimento de atletas de nado sincronizado / The different phases of the menstrual cycle do not influence the performance of synchronized swimming athletes / Las diferentes fases del ciclo menstrual no influencian el rendimiento de atletas de nado sincronizado

RESUMO Introdução: O conhecimento referente à influência das fases do ciclo menstrual no desempenho ainda é inconclusivo. Objetivo: Analisar o desempenho físico e técnico de atletas de nado sincronizado em três diferentes fases do ciclo menstrual. Métodos: Seis atletas de nível nacional (idade: 17,6 ± 6,15) com ciclo menstrual normal foram avaliadas, considerando as seguintes fases do ciclo menstrual, folicular (F), ovulatória (O) e lútea (L). Foram avaliados os parâmetros antropométricos, neuromotores, o deslocamento vertical, alçada de eggbeater e o desempenho na rotina técnica. Resultados: Não foram encontradas alterações de parâmetros antropométricos, força dos membros superiores (F; O; L); abdominal (F; O; L) e flexibilidade (F; O; L). Nos testes específicos, tanto deslocamento vertical, alçada de eggbeater (F; O; L) e desempenho técnico (F: 77 ± 4, O: 80 ± 5, L: 77 ± 4; pontos) não se alteraram ao longo das fases do ciclo menstrual. Conclusão: Os dados do presente estudo indicam que as fases do ciclo menstrual não exercem influência direta no desempenho de atletas de nado sincronizado.

ABSTRACT Introduction: Knowledge regarding the influence of the phases of the menstrual cycle on the performance is still inconclusive. Objective: To analyze the physical and technical performance of synchronized swimmers in three different phases of the menstrual cycle. Methods: Six athletes of national level (age: 17.6±6.15) with normal menstrual cycle were evaluated considering the following phases of the menstrual cycle, namely, follicular (F), ovulatory (O) and luteal (L). Anthropometric, and neuromotor parameters, vertical displacement, eggbeater kick and performance in the technical routine were evaluated. Results: No changes were found in the anthropometric parameters, strength of the upper limbs (F; O; L); abdominal (F; O; L) and flexibility (F; O; L). In the specific tests, vertical displacement, eggbeater kick (F; O; L), and technical performance (F: 77±4; O: 80±5; L: 77±4 points) did not change throughout the menstrual cycle. Conclusion: The data of the present study indicate that the phases of the menstrual cycle do not directly influence the performance of synchronized swimming athletes.

RESUMEN Introducción: El conocimiento referente a la influencia de las fases del ciclo menstrual en el rendimiento sigue siendo inconcluso. Objetivo: Analizar el rendimiento físico y técnico de atletas de nado sincronizado en tres fases diferentes del ciclo menstrual. Métodos: Se evaluaron seis atletas de nivel nacional (edad: 17.6 ± 6.15) con ciclo menstrual normal, teniendo en cuenta las siguientes fases del ciclo menstrual: folicular (F), ovulatoria (O) y lútea (L). Se evaluaron los parámetros antropométricos, neuromotores, el desplazamiento vertical, el eggbeater ("batidora") y el rendimiento en la rutina técnica. Resultados: No se encontraron cambios en parámetros antropométricos, fuerza de las extremidades superiores (F, O, L); abdominal (F, O, L) y flexibilidad (F, O, L). En las pruebas específicas, tanto desplazamiento vertical, eggbeater (F, O; L) y rendimiento técnico (F: 77 ± 4, O: 80 ± 5, L: 77 ± 4 puntos) no se alteraron a lo largo de las fases del ciclo menstrual. Conclusión: Los datos de este estudio indican que las fases del ciclo menstrual no ejercen ninguna influencia directa sobre el rendimiento de atletas de nado sincronizado.

Workload of horses on a water treadmill: effect of speed and water height on oxygen consumption and cardiorespiratory parameters.

BACKGROUND: Despite the use of water treadmills (WT) in conditioning horses, the intensity of WT exercise has not been well documented. The workload on a WT is a function of water height and treadmill speed. Therefore, the purpose of this study was to determine the effects of these factors on workload during WT exercise. Fifteen client-owned Quarter Horses were used in a randomized, controlled study. Three belt speeds and three water heights (mid cannon, carpus and stifle), along with the control condition (dry treadmill, all three speeds), were tested. Measured outcomes were oxygen consumption (V̇O2), ventilation (respiratory frequency, tidal volume (VT)), heart rate (HR), and blood lactate. An ergospirometry system was used to measure V̇O2 and ventilation. Linear mixed effects models were used to examine the effects of presence or absence of water, water height and speed (as fixed effects) on measured outcomes. RESULTS: Water height and its interaction with speed had a significant effect on V̇O2, VT and HR, all peaking at the highest water level and speed (stifle at 1.39 m/s, median V̇O2 = 16.70 ml/(kg.min), VT = 6 L, HR = 69 bpm). Respiratory frequency peaked with water at the carpus at 1.39 m/s (median 49 breaths/min). For a given water height, the small increments in speed did not affect the measured outcomes. Post-exercise blood lactate concentration did not change. CONCLUSIONS: Varying water height and speed affects the workload associated with WT exercise. The conditions utilized in this study were associated with low intensity exercise. Water height had a greater impact on exercise intensity than speed.