Effects of Pull-Up Training on 50-Meter Freestyle Swimming Performance: A Preliminary Analysis.

This study examined the impact of incorporating pull-up exercises into the training routines of competitive swimmers on their performance outcomes. Eight swimmers (average age 21 ± 6.7 years, height 178 ± 5.3 cm, body mass 73 ± 7.0 kg) were selected and participated in a 10-week intervention, during which pull-up exercises were added to their regular strength training sessions. Performance was evaluated through tests measuring the sprint start speed and 50-meter freestyle swim times before and after the intervention. Statistical analyses showed significant improvements in swimming explosive strength, as measured by a 15-meter time trial (p = 0.014). In addition, resistance to explosive strength, as indicated by total time in a 50-meter time trial, improved significantly (p = 0.008), particularly in the first 25 meters (p = 0.014), although not in the second 25 meters (p = 0.078). These findings highlight the critical role of upper body strength and power in enhancing swimming performance, especially in sprint events. In conclusion, incorporating pull-up exercises into training regimens appears promising for improving upper body strength and power among swimmers. Future research should address the study's limitations by using larger, more homogeneous samples and more rigorously controlling variables such as age, gender, and training schedules. These efforts could provide clearer insights into the effectiveness of pull-up exercises in optimizing swimming performance, particularly in sprint disciplines.

Influence of Conventional Resistance Training Compared to Core Exercises on Road Cycling Power Output.

Conventional strength training and core exercises are commonly prescribed to improve cycling performance. Although previous studies have explored the utility of strength training in various cycling populations, this intervention has never been compared to core exercises. Thirty-six trained road cyclists were divided into three groups of 12 participants that performed either no strength training, conventional strength training, or core exercises, in all cases together with their regular cycling training during a 12-week period. Peak power outputs (POs) across different durations (five seconds, 60 seconds, five minutes, and 20 minutes) were recorded before and after the intervention. The results of the present study showed higher increases in relative PO with conventional strength training when compared to core training and no strength training for all measured durations: five-second Δ = 1.25 W/kg vs 0.47 W/kg and -0.17 W/kg; 60-second (Δ = 0.51 W/kg vs 0.13 W/kg and 0.02 W/kg; five-minute Δ = 0.22 W/kg vs 0.06 W/kg and 0.05 W/kg; and 20-minute Δ = 0.22 W/kg vs 0.07 W/kg and 0.06 W/kg. According to the data obtained in this study, conventional strength training is superior to core exercises, and no strength training was performed by trained road cyclists. Accordingly, it is recommended that this population incorporates strength training during their regular weekly workouts.

An Update Of The Allen & Coggan Equation To Predict 60-Min Power Output In Cyclists Of Different Performance Levels.

The Allen & Coggan protocol suggests that 95% of the power output during a 20-min time trial is a valid surrogate for 60-min maximal power. The validity of this concept has not been studied previously in cyclists with different performance levels. As a result, we classified 120 cyclists in our study as recreationally trained, trained, well trained or professional, based on their maximal oxygen consumption. Participants performed a functional threshold power testing protocol based on a 20-min time trial and a 60-min time trial, separated by a 72-hour rest. Sixty-minute maximal power was successfully modeled with 20-min maximal power and performance group using 2/3 of the dataset (R2=0.77, 95% CrI [0.74, 0.79]) with different coefficients for each group: Professional: PO60min=PO20min × 0.96; well trained: PO60min=PO20min × 0.95; trained: PO60min=PO20min × 0.92 and recreationally trained: PO60min=PO20min × 0.88. The predictions of the original equation and our model were assessed using the remaining third of the data. The predictive performance of the updated equation was better (original: R2=0.51, mean absolute error=27 W, mean bias=-12 W; updated: R2=0.54, mean absolute error=25 W, mean bias=-7 W).

Effects of Plyometric Training Direction on Physical Performance in Basketball Players.

PURPOSE: The aim of this study was to analyze the effects of plyometric training direction on jumping, sprinting, and change-of-direction ability in basketball players. METHODS: Forty male basketball players (21.8 [3.8] y), from 4 teams that competed in regional and national championships, were randomly assigned to 1 of 4 groups: (1) vertical jump group, (2) horizontal jump group, (3) vertical and horizontal jump group, and (4) control group. The subjects followed a plyometric training program twice a week for 6 weeks, differing in the execution direction of the jumps. All groups performed the same total training volume of acyclic and cyclic jumps controlled through the number of contacts per session. Pretraining and posttraining measurements included (1) rocket jump, (2) Abalakov jump, (3) horizontal jump, (4) 20-m linear sprint, and (5) V-Cut change-of-direction test. RESULTS: The vertical and horizontal jump group showed significant increases in all performance variables examined, except for linear sprint performance, in which no group improved. The vertical jump group showed significant improvements in rocket jump and Abalakov jump (P < .01), but worsened significantly in terms of sprint performance (P < .05). The horizontal jump group showed significant increases in rocket jump and horizontal jump (P < .001-.01). Furthermore, all experimental groups showed improved V-Cut change-of-direction test performance. CONCLUSIONS: These results indicate that combining vertical and horizontal jumps induces improvements in more capabilities than does training only vertical or horizontal jumps with the same training volume. Training only vertical or horizontal jumps will improve performance mainly in vertically or horizontally oriented tasks, respectively.

Osgood-Schlatter Disease: Appearance, Diagnosis and Treatment: A Narrative Review.

Osgood-Schlatter disease is the most common osteochondritis of the lower limb in sport-practicing children and adolescents. Its manifestation usually coincides with the appearance of the secondary ossification center of the tibia and is linked to the practice of sports with an explosive component. In the present study, a review of the factors related to its appearance, diagnosis and treatment was carried out. Its appearance seems to be multifactorial and related to multiple morphological, functional, mechanical and environmental factors. Given all the above, risk factor reduction and prevention seem the most logical strategies to effectively prevent the appearance of the condition. In addition, it is essential to create prevention programs that can be objectively assessed and would allow to stop the progress of the pathology, particularly in those sports where high forces are generated on the insertion zone of the patellar tendon at sensitive ages. More studies are needed to clarify which type of treatment is the most appropriate-specific exercises or the usual care treatment.

Acute Kidney Injury and Hyponatremia in Ultra-Trail Racing: A Systematic Review.

Background and objectives: Ultra-trail races can cause episodes of acute kidney injury (AKI) and exercise-associated hyponatremia (EAH) in healthy subjects without previous renal pathology. This systematic review aims to review the incidence of these two syndromes together and separately taking into account the length and elevation of the ultra-trail race examined. Materials and Methods: A systematic review was conducted through electronic search in four electronic databases (PubMed, EBSCO, Web of Science and Alcorze). Results: A total of 1127 articles published between January 2006 and December 31, 2021 were included, 28 of which met the inclusion criteria. The studies were categorized according to the length and stages of the race in four categories: medium (42 to 69 km), long (70 to 99 km), extra (>100 km) and multi-stage if they included various stages. A total of 2950 runners (666 females and 2284 males) were extracted from 28 publications. The AKI incidence found was 42.04% (468 cases of 1113), and 195 of 2065 were diagnosed with EAH, accounting for 9.11%. The concurrence of both pathologies together reached 11.84% (27 individuals) from a total of 228 runners with AKI and EAH simultaneously analyzed. Sorted by race category, the AKI+EAH cases were distributed as follows: 18 of 27 in the extra (13.63% and n = 132), 4 in the large (5.79% and n = 69) and 5 in the medium category (18.15% and n = 27). Conclusions: According to these results, extra and medium races showed a similar incidence of AKI+EAH. These findings underline the importance of the duration and intensity of the race and may make them responsible for the etiology of these medical conditions. Due to their variable incidence, EAH and AKI are often underdiagnosed, leading to poorer prognosis, increased condition seriousness and hindered treatment. The results of this review urge participants, coaches and race organizers to take measures to improve the early diagnosis and urgent treatment of possible EAH and AKI cases.

The Effectiveness of Shoulder Mobility and Strength Programs in Competitive Water-Polo Players.

BACKGROUND: Water-polo is the water sport with the highest incidence of injuries, with shoulder pain being the most common one. The understanding of risk factors and guidance on preventive measures is essential in this sport discipline. The aim of this study was to determine the effects of a specific 6-week training plan on range of motion (ROM) and joint strength levels in a group of professional water-polo players. METHODS: Quasi-experimental study with a sample of 28 participants (age: 20.1 ± 2.5 years; height: 176.9 ± 6.2 cm; body mass: 74.6 ± 8.1 kg). Three study groups, which consisted of one control group and two experimental groups, were established. Two repeated measurements, pre and post intervention, were performed. During these measurements, ROM of the glenohumeral joint was analyzed both in external (ER) and internal (IR) rotation, as well as the maximal isometric strength. CONCLUSIONS: The application of a training program improved glenohumeral joint ROM. ER and IR evolve differently in both shoulders. ER improved only in the throwing arm only in the group undergoing intervention but for the non-dominant side, improvements were observed in both ER and IR, regardless of whether or not they had followed the intervention plan. No improvements were observed in either the isometric strength or contralateral asymmetries.

Effects of ergo-nutritional strategies on recovery in combat sports disciplines.

Introduction: In order to improve the recovery process in combat sports disciplines, ergo-nutritional strategies could be an effective option in training and competition. Some of these ergo-nutritional aids could improve performance but literature references are scarce, with controversial results regarding actual recovery effects. This systematic review aimed to examine which ergo-nutritional methods are most effective for assisting in the recovery process in combat sports, and to determine the appropriate training stimuli. This systematic review was carried out following the Preferred Reporting Items for Systematic Review (PRISMA) guidelines. A computerized search was performed in PubMed, Web of Science, the Cochrane Collaboration Database, Evidence Database, Evidence Based Medicine Search review, National Guidelines, EM-BASE, Scopus and Google Scholar system (from 1995 to April 30, 2021). The PICOS model was used to define inclusion and exclusion criteria. Out of 123 studies initially found, 18 met the eligibility criteria and were included in the review. Data from 367 athletes from different disciplines were examined. The evidence was grouped in 4 areas: oxidative stress, muscle and energy recovery, muscle repair, and metabolic acidosis. Evidence showed that vitamins, minerals, and some natural ergo-nutritional products are effective as antioxidants. Carbohydrates and protein determine the recovery effect. Sodium bicarbonate has a role as primary acidosis metabolic delayer. Accordingly, ergo-nutritional aids can help in the recovery process. Considering the effects outlined in the literature, more studies are needed to provide firm evidence.

Introducción: Para mejorar el proceso de recuperación en las disciplinas deportivas de combate, las estrategias ergo-nutricionales son una opción eficaz en el entrenamiento y la competición. Algunas de estas alternativas mejoran el rendimiento, pero actualmente existe una escasa bibliografía con resultados controvertidos relacionados con el efecto de recuperación. Esta revisión sistemática tuvo como objetivo determinar qué estrategias ergo-nutricionales son más efectivas en los procesos de recuperación. Se llevó a cabo siguiendo las pautas Preferred Reporting Items for Systematic Review (PRISMA). Se realizó una búsqueda computarizada en PubMed, Web of Science, Cochrane Collaboration Database, Evidence Database, Evidence Based Medicine Search review, National Guidelines, EM-BASE, Scopus y el sistema Google Scholar (desde 1995 hasta el 30 de abril de 2021). Se utilizó el modelo PICOS para definir los criterios de inclusión y exclusión. De los 123 estudios encontrados inicialmente, 18 cumplieron los criterios de elegibilidad y fueron incluidos. Se examinaron datos de 367 atletas de diferentes disciplinas. La evidencia se agrupó en 4 áreas: estrés oxidativo, recuperación muscular y energética, reparación muscular y acidosis metabólica. La evidencia mostró que las vitaminas, los minerales y algunos productos ergo-nutricionales naturales son eficaces como antioxidantes, los hidratos de carbono y las proteínas determinan su efecto recuperador y el bicarbonato de sodio es el principal retardador metabólico de la acidosis. Se destaca la importancia de aceptar un plan ergo-nutricional para mejorar el proceso de recuperación. A pesar de ello, y teniendo en cuenta los efectos descritos en la literatura, se necesitan más estudios para reforzar la evidencia actual.

768-km Multi-Stage Ultra-Trail Case Study-Muscle Damage, Biochemical Alterations and Strength Loss on Lower Limbs.

A series of case studies aimed to evaluate muscular fatigue in running a 768-km ultra-trail race in 11 days. Four non-professional athletes (four males) were enrolled. Muscle damage blood biomarkers (creatine kinase (CK), lactodeshydrogenase (LDH), aspartate transaminase (AST) and alanine aminotransferase (ALT) and lower limb strength were evaluated by using Bosco jumps test; squat jump (SJ), countermovement jump (CMJ) and Abalakov jump (ABA) were assessed before (pre), after the race (post) and for two and nine days during the recovery period (rec2 and rec9), respectively. Results showed: pre-post SJ = -28%, CMJ = -36% and ABA = -21%. Values returned to basal during rec9: SJ = -1%, CMJ = -2% or even exceeded pre-values ABA = +3%. On the contrary, muscle damage blood biomarkers values increased at post; CK = +888%, LDH = +172%, AST = +167% and ALT = +159% and the values returned gradually to baseline at rec9 except for AST = +226% and ALT = +103% which remained higher. Nonparametric bivariate Spearman's test showed strong correlations (Rs ≥ 0.8) between some jumps and muscle damage biomarkers at post (SJ-LDH Rs = 0.80, SJ-AST Rs = 0.8, ABA-LD H Rs = 0.80 and ABA-AST Rs = 0.80), at rec2 (SJ-CK Rs = 0.80 and SJ-ALT Rs = 0.80) and even during rec9 (ABA-CK). Similarly, some parameters such as accumulated elevation and training volume showed a strong correlation with LDH values after finishing the ultra-trail race. The alteration induced by completing an ultra-trail event in the muscle affects lower limb strength and may in some circumstances result in serious medical conditions including post- exertional rhabdomyolysis.

Functional Threshold Power as an Alternative to Lactate Thresholds in Road Cycling.

ABSTRACT: Sitko, S, Cirer-Sastre, R, Corbi, F, and López-Laval, I. Functional threshold power as an alternative to lactate thresholds in road cycling. J Strength Cond Res 36(11): 3179-3183, 2022-This study assessed the relationship between functional threshold power (FTP) and 7 lactate landmarks (Dmax, modified Dmax, fixed blood lactate concentrations of 2 and 4 mmol·L -1 , lactate increases of 1 and 2 mmol·L -1 above baseline, and lactate increases of 1.5 mmol·L-1 above the point of minimum ratio between lactate and work rate) in a sample of 46 road cyclists with a wide range of fitness levels (age 38 ± 9 years, height 177 ± 9 cm, body mass 71.4 ± 8.6 kg, body mass index 22.7 ± 2.2 kg·m -1 , fat mass 7.8 ± 4%, and V̇ o2 max = 61.1 ± 9.1 ml·min -1 ·kg -1 ). The cyclists performed a graded exercise test in which power outputs (POs) at the lactate landmarks were identified. Functional threshold power was established as 95% of the PO during a 20-minute test. Significance was set as p < 0.05. Statistical analyses revealed large to very large correlations between PO, relative PO (RPO), and cadence at FTP and lactate thresholds (LTs) established through Dmax, modified Dmax, and fixed lactate concentrations of 4 mmol·L -1 ( r = 0.68-0.93). Significant differences ( p < 0.001) were also observed for PO and RPO at FTP, fixed blood lactate concentrations of 2 mmol·L -1 , and lactate increases of 1 mmol·L -1 above baseline. Therefore, although FTP estimated from a 20-minute test is strongly related to several lactate landmarks, caution is required when substituting this concept for LTs. This information will allow coaches, cyclists, and scientists to better choose assessments when attempting to estimate LT through power-based field testing.

Relationship between functional threshold power, ventilatory threshold and respiratory compensation point in road cycling.

BACKGROUND: The purpose of this study was to assess the relationship between power output and relative power output at the functional threshold power, ventilatory threshold and respiratory compensation point in road cyclists. METHODS: Forty-six road cyclists (age 38±9 years; height 177±9 cm; body mass 71.4±8.6 kg; Body Mass Index 22.7±2.2 kg·m-1; fat mass 7.8±4%, V̇O2max 61.1±9.1 mL·min-1·kg-1) performed a graded exercise test in which power output and relative power output at the ventilatory landmarks were identified. Functional threshold power was established as 95% of the power output during a 20-minute test. RESULTS: Power output and relative power output at the functional threshold power were higher than at the ventilatory threshold (P<0.001). There were very large to near perfect correlations for power output (95% CI for r from 0.71 to 0.9) and relative power output (95% CI for r from 0.79 to 0.93) at the functional threshold power and respiratory compensation point. Mean bias in power output and relative power output measured at RCP compared with FTP was not significant (mean bias 95% CI from -7 to 10 W and -0.1 to 0.1 W/kg, respectively). CONCLUSIONS: Power output and relative power output at the functional threshold power are higher than at the ventilatory threshold. Power output and relative power output at the functional threshold power and respiratory compensation point are strongly related, but caution is required when using both concepts indistinctly.

Five-Minute Power-Based Test to Predict Maximal Oxygen Consumption in Road Cycling.

PURPOSE: To examine the ability of a multivariate model to predict maximal oxygen consumption (VO2max) using performance data from a 5-minute maximal test (5MT). METHODS: Forty-six road cyclists (age 38 [9] y, height 177 [9] cm, weight 71.4 [8.6] kg, VO2max 61.13 [9.05] mL/kg/min) completed a graded exercise test to assess VO2max and power output. After a 72-hour rest, they performed a test that included a 5-minute maximal bout. Performance variables in each test were modeled in 2 independent equations, using Bayesian general linear regressions to predict VO2max. Stepwise selection was then used to identify the minimal subset of parameters with the best predictive power for each model. RESULTS: Five-minute relative power output was the best explanatory variable to predict VO2max in the model from the graded exercise test (R2 95% credibility interval, .81-.88) and when using data from the 5MT (R2 95% credibility interval, .61-.77). Accordingly, VO2max could be predicted with a 5MT using the equation VO2max = 16.6 + (8.87 × 5-min relative power output). CONCLUSIONS: Road cycling VO2max can be predicted in cyclists through a single-variable equation that includes relative power obtained during a 5MT. Coaches, cyclists, and scientists may benefit from the reduction of laboratory assessments performed on athletes due to this finding.

The Recovery Umbrella in the World of Elite Sport: Do Not Forget the Coaching and Performance Staff.

In the field of sports science, the recovery umbrella is a trending topic, and even more so in the world of elite sports. This is evidenced by the significant increase in scientific publications during the last 10 years as teams look to find a competitive edge. Recovery is recognized to be an integral component to assist athlete preparation in the restoration of physical and psychological function, and subsequently, performance in elite team sports athletes. However, the importance of recovery in team staff members (sports coaches and performance staff) in elite sports appears to be a forgotten element. Given the unrelenting intense nature of daily tasks and responsibilities of team staff members, the elite sports environment can predispose coaches to increased susceptibility to psycho-socio physiological fatigue burden, and negatively affect health, wellbeing, and performance. Therefore, the aim of this opinion was to (1) develop an educational recovery resource for team staff members, (2) identify organizational task-specific fatigue indicators and barriers to recovery and self-care in team staff members, and (3) present recovery implementation strategies to assist team staff members in meeting their organizational functions. It is essential that we do not forget the coaching and performance staff in the recovery process.

Characteristics of Pedaling Muscle Stiffness among Cyclists of Different Performance Levels.

Background and Objectives: The aim of the present study was to compare the impact of an incremental exercise test on muscle stiffness in the rectus femoris (RF), vastus lateralis (VL), biceps femoris (BF), and gastrocnemius (GL) among road cyclists of three performance levels. Materials and Methods: The study group consisted of 35 cyclists grouped according to their performance level; elite (n = 10; professional license), sub-elite (n = 12; amateur license), and recreational (n = 13; cyclosportive license). Passive muscle stiffness was assessed using myometry before and after an incremental exercise test. Results: There was a significant correlation between time and category in the vastus lateralis with stiffness increases in the sub-elite (p = 0.001, Cohen's d = 0.88) and elite groups (p = 0.003, Cohen's d = 0.72), but not in the recreational group (p = 0.085). Stiffness increased over time in the knee extensors (RF, p < 0.001; VL, p < 0.001), but no changes were observed in the knee flexors (GL, p = 0.63, BF, p = 0.052). There were no baseline differences among the categories in any muscle. Conclusions: Although the performance level affected VL stiffness after an incremental exercise test, no differences in passive stiffness were observed among the main muscles implicated in pedaling in a resting state. Future research should assess whether this marker could be used to differentiate cyclists of varying fitness levels and its potential applicability for the monitoring of training load.

Exercise-Induced Release of Cardiac Troponins in Adolescent vs. Adult Swimmers.

To examine the exercise-induced release of cardiac troponin T (cTnT) in adolescent and adult swimmers. Thirty-two trained male (18 adolescents, 14 adults) swam at maximal pace in a 45 min distance trial, and blood samples were drawn before, immediately and 3 h after exercise for subsequent cTnT analysis and comparison. Having comparable training experience and baseline values of cTnT (p = 0.78 and p = 0.13), adults exercised at lower absolute and relative intensity (p < 0.001 and p < 0.001, respectively), but presented higher immediate cTnT after exercise than adolescents (p < 0.001). Despite that, peak concentrations were observed at 3 h post exercise and peak elevations were comparable between groups (p = 0.074). Fourteen (44%) apparently healthy subjects exceeded the cutoff value for myocardial infarction (MI). Adolescents presented a delayed elevation of cTnT compared with adults, but achieved similar peak values.

Influence of maturational status in the exercise-induced release of cardiac troponin T in healthy young swimmers.

OBJECTIVES: To determine the influence of maturational status on the release of cardiac troponin T (cTnT) induced by a bout of 30min, high-intensity, continuous exercise. DESIGN: Quasi-experimental, cross-sectional study. METHODS: Seventy male, young, well trained swimmers (age range 7-18 years, training experience 1-11 years) were classified by maturational stages: Tanner stage I (n=14), II (n=15), III (n=15), IV (n=13), and V (n=13). Participants underwent a distance-trial of 30min continuous swimming, and cTnT was measured before, immediately after and 3h after exercise. Changes in cTnT over time were compared among groups, and associated with exercise load. RESULTS: Basal cTnT was higher in Tanner-V (3.8-8.1ng/L) compared with I (1.5-5.5ng/L, p<0.001), II (1.5-4.5ng/L, p<0.001) and III (1.5-6.8ng/L, p=0.003), and in IV (1.5-6.3ng/L) compared with II (p=0.036). Maximal elevations of cTnT from baseline were notable (p<0.001) and comparable among maturational stages (p=0.078). The upper reference limit for myocardial injury was exceeded in 35.7% of the participants, without differences among groups (p=0.18). Baseline cTnT correlated with participant characteristics, and maximal cTnT elevations from baseline with exercise internal load (%HRpeak, rs=0.34, p= 0.003; %HRmean, rs=0.28, p=0.02). CONCLUSIONS: Maturational status influences positively absolute pre- and post-exercise cTnT but not its elevation after a bout of 30min, high-intensity, continuous exercise.

Evidence-based post exercise recovery in combat sports: a narrative review.

INTRODUCTION: Some methods such as ergo nutritional aids, cooling or massage among others could improve recovery in combat sports (CS). The effects, doses, duration, and timing of these methods remains unknown. Nowadays, there is no clear consensus regarding the recovery strategies and it is necessary to understand the type of fatigue induced in CS and its underlying mechanisms. The main aim of this article is to review the update literature related to recovery strategies in CS. EVIDENCE ACQUISITION: A literature search was conducted following preferred reporting items for review statement on the topic of: "combat sports," "recovery," "nutrition," "fatigue," "ergogenic aids," "weight cutting" and "hydration." EVIDENCE SYNTHESIS: The initial search of the literature detected 369 articles about CS. Later, 307 were excluded after being determined unrelated to recovery or after failure to fulfill the inclusion criteria. Of the 80 included articles, 19 satisfied the final inclusion criteria. CONCLUSIONS: To optimize CS performance, adequate recovery is required during training and competition processes. Traditional ergo nutritional supplementation of carbohydrates and proteins combined. Besides, the consumption of evidence supported supplementation (green tea, beetroot gels, creatine or alkaline water) improve recovery processes. Further methods of recovery including physical (cold water immersion, massage or photobiomodulation) and physiological (types of active recovery, sleep and rest) therapies have also been shown useful. This narrative review elucidates the important role of recovery techniques in CS.

Effects of a low-carbohydrate diet on body composition and performance in road cycling: a randomized, controlled trial.

INTRODUCTION: Low-carbohydrate diets are frequently used to improve performance in endurance sports, often with contradictory results. This study aimed to assess whether a low-carbohydrate diet can outperform an isocaloric conventional diet for improving body composition and performance in a sample of twenty-six trained male road cyclists (previous experience in cyclosportive events, 7.6 ± 4.4 years; age, 26.9 ± 4.9 years; weekly training volume, 7.8 ± 2.9 hours; height, 176 ± 7 centimeters; body fat percentage, 9.7 ± 0.8 %; weight, 65.3 ± 2.3 kg). Detraining and pretreatment periods in which nutrition and training were standardized were followed by an eight-week long intervention in which cyclists consumed either a low-carbohydrate diet (15 % of calories from carbohydrates) or a conventional endurance sports diet while maintaining the same training volumes and intensities. Body composition was assessed through electrical impedance, and performance was evaluated through a twenty-minute time trial performed on a smart bike trainer. The results revealed an overall improvement over time in absolute and relative power, body mass, and body fat for both groups, whilst the improvement in absolute power was comparable. The improvements seen in relative power (p = 0.042), body mass (p = 0.006), and body fat (p = 0.01) were significantly higher in the low-carbohydrate group. We concluded that eight weeks of a low-carbohydrate diet significantly reduced body weight and body fat percentage, and improved 20-minute relative power values in a sample of road cyclists when compared to an isocaloric conventional diet.

INTRODUCCIÓN: Las dietas bajas en carbohidratos se usan con frecuencia para mejorar el rendimiento en los deportes de resistencia, a menudo con resultados contradictorios. Este estudio tuvo como objetivo evaluar si una dieta baja en carbohidratos puede superar a una dieta convencional isocalórica para mejorar la composición corporal y el rendimiento en una muestra de veintiséis ciclistas de carretera masculinos entrenados (experiencia previa en eventos cicloportivos, 7,6 ± 4,4 años; edad, 26,9 ± 4,9 años; volumen de entrenamiento semanal, 7,8 ± 2,9 horas; altura, 176 ± 7 centímetros; porcentaje de grasa corporal, 9,7 ± 0,8 %; peso, 65,3 ± 2,3 kg). Los períodos de desentrenamiento y pretratamiento, en los que se estandarizaron la nutrición y el entrenamiento, fueron seguidos por una intervención de ocho semanas de duración en la que los ciclistas consumieron una dieta de bajo contenido en carbohidratos (15 % de calorías de los carbohidratos) o una dieta convencional para deportes de resistencia, manteniendo los mismos volúmenes de entrenamiento e intensidades. La composición corporal se evaluó a través de la impedancia eléctrica y el rendimiento se evaluó a través de una prueba contrarreloj de veinte minutos realizada en un rodillo de bicicleta inteligente. Los resultados revelaron una mejora general en el tiempo en cuanto a potencia absoluta y relativa, masa corporal y grasa corporal para ambos grupos, mientras que la mejora en potencia absoluta fue comparable. Las mejoras de la potencia relativa (p = 0,042), la masa corporal (p = 0,006) y la grasa corporal (p = 0,01) fueron significativamente mayores en el grupo bajo en carbohidratos. Se concluye que ocho semanas de una dieta baja en carbohidratos redujeron significativamente el peso corporal y el porcentaje de grasa corporal, y mejoraron los valores de potencia relativa de 20 minutos en una muestra de ciclistas de carretera en comparación con una dieta convencional isocalórica.

Effects of a 75-km mountain ultra-marathon on heart rate variability in amateur runners.

BACKGROUND: This study examined the effects of a mountain ultra-marathon (MUM) on the activity of the autonomous nervous system through heart rate variability (HRV) monitoring and determined whether this variable related to final performance. METHODS: Heart rate and HRV were measured in eight male amateur runners (aged 37-60 years). Measurements were recorded before and after the event, in resting conditions, as well as continuously throughout the whole MUM. In addition, percentage (%) of heart rate reserve (HRres) and partial and total times during the race were analyzed. RESULTS: Average heart rate (HRavg) measured at rest was increased after the event (+37%). Standard deviation of successive differences (SDSD) and the square root of the mean squared differences of successive NN intervals (RMSSD) were reduced after the MUM (-56% and -59%, respectively). There was a positive relationship between the frequency-domain index normalized low frequency power (PLFn) measured at rest before the event and race time (0.79) while there was a negative relationship between race time and the difference in HRavg before and after the event. In the last half of the event, there was a high correlation (Spearman coefficient of correlation >0.9) between race time and the standard deviation of the NN intervals (SDNN) registered during the race. CONCLUSIONS: Autonomous cardiac regulation can be related to the performance in a mountain ultra-marathon. HRV monitoring could represent a practical tool for the evaluation of the relationship between the autonomous nervous system activity and performance in a mountain ultra-marathon.