Peak Running Velocity vs. Critical Speed: Which One Is Better to Prescribe Endurance Training to Recreational Runners?

ABSTRACT: Figueiredo, DH, Figueiredo, DH, Manoel, FA, and Machado, FA. Peak running velocity vs. critical speed: which one is better to prescribe endurance training to recreational runners? J Strength Cond Res 37(9): 1783-1788, 2023-This study aimed to evaluate the effects of 5 weeks of training prescribed by peak running velocity obtained on the track (Vpeak_TR) and their respective time limit (Tlim), as well as by critical speed (CS), on physiological and endurance performance parameters in recreational runners. Twenty-two male runners were distributed into a Vpeak_TR group (GVP) and CS group (GCS) with a predefined program, alternating moderate-intensity continuous training and high-intensity interval training. Maximum oxygen uptake (V̇O2max), and its respective velocity (vV̇O2max), Vpeak_TR, Tlim at 100% Vpeak_TR, 5-km running performance, CS, and D' (maximum distance covered above CS) were assessed at pretraining and posttraining period. There was a significant increase from pretraining to posttraining in Vpeak_TR (GVP = 4.5 ± 3.1% vs. GCS = 7.5 ± 4.2%), vV̇O2max (GVP = 3.9 ± 3.8% vs. GCS = 8.6 ± 6.7%), and mean velocity 5-km (GVP = 5.6 ± 3.3% vs. GCS = 7.3 ± 3.5%) and decrease in 5-km time (GVP = -5.1 ± 3.0% vs. GCS = -6.8 ± 3.0%). CS and V̇O2max significantly improved in GCS (9.3 ± 8.4% and 6.0 ± 6.8%, respectively), with no difference for GVP (2.8 ± 5.6% and 1.3 ± 8.4%, respectively). No differences were observed between groups for all variables. These findings give further supports to the notion that both variables obtained on the track are valid tools to prescribed training in recreational runners.

Effect of 3-week progressive overloading and 1-week tapering on performance, internal training load, stress tolerance and heart rate variability in under-19 Brazilian badminton players / Efecto de la sobrecarga progresiva de 3 semanas y la reducción gradual de 1 semana sobre el rendimiento, la carga de entrenamiento interno, la tolerancia al estrés y la variabilidad de la frecuencia cardíaca en jugadores brasileños de Bádminton menores de 19 años

Objective: This study aimed to determine the effect of 3-week progressive overloading and 1-week tapering during a preseason on performance, internal training load, stress tolerance, and heart rate variability in under-19 Brazilian badminton players. Material and method: Eight male under-19 badminton players (age 16.1 ± 0.6 years; height 1.68 ± 7.7 m; body mass 57.2 ± 5.8 kg; body mass index 20.3 ± 2.5 kg∙m-2; body fat 8.0 ± 2.7 %), competing at the state level had physical and physiological monitored over four weeks during pre-season. Players underwent a badminton-specific movement agility test, 5-m multiple shuttle test, Yo-Yo Intermittent Recovery test level 1, and performed vertical jumps before and after the pre-season. During the training, the heart rate variability and internal training load were monitored daily, and weekly were stress tolerance was recorded by psychometric responses. Results: The players showed significant improvements in all performance variables assessed after the training period. The internal training load during overloading was higher (1635 ± 109.9; 2490 ± 124; 2850 ± 210 AU) compared to tapering (1335 ± 100 AU). The stress tolerance decreased during overloading (4.0 ± 0.7; 8.2 ± 1.3; 10.1 ± 1.4) and increased during tapering (5.5 ± 1.5). In addition, higher internal training load during overloading resulted in a greater reduction in root-mean-square difference of successive R-R intervals (lnRMSSDmean) (4.2 ± 0.2; 4.1 ± 0.1; 4.0 ± 0.1 ms) and a smaller coefficient of variation (lnRMSSDcv) (4.5 ± 2.6; 2.1 ± 1.2; 1.4 ± 0.9 %), and the significant reduction in the internal training load during tapering led to a decrease in lnRMSSDmean (1.3 ± 0.5 ms).(AU)

Objetivo: Este estudio tuvo como objetivo determinar el efecto de la sobrecarga progresiva de 3 semanas y la reducción gradual de 1 semana durante una pretemporada sobre el rendimiento, la carga de entrenamiento interno, la tolerancia al estrés y la variabilidad de la frecuencia cardíaca en jugadores de bádminton brasileños menores de 19 años. Material y método: Ocho jugadores masculinos de bádminton sub-19 (edad 16,1 ± 0,6 años; altura 1,68 ± 7,7 m; masa corporal 57,2 ± 5,8 kg; índice de masa corporal 20,3 ± 2,5 kg∙m-2; grasa corporal 8,0 ± 2,7 %), que competían a nivel estatal fueron monitoreados en sus aspectos físicos y fisiológicos durante cuatro semanas en la pretemporada. Los jugadores realizaron un test de agilidad específico de bádminton, el test 5-m multiple shuttle test, el test Yo-Yo y realizaron saltos verticales antes y después de la pretemporada. Durante el entrenamiento, se monitoreó diariamente la variabilidad de la frecuencia cardíaca y la carga interna de entrenamiento. Además, semanalmente se registró la tolerancia al estrés mediante respuestas psicométricas. Resultados: Los jugadores mostraron mejoras significativas en todas las variables de rendimiento evaluadas después del período de entrenamiento. La carga de entrenamiento interna durante la sobrecarga fue más grande (1.635 ± 109,9; 2.490 ± 124; 2.850 ± 210 AU) en comparación con la última semana de cargas reducidas (1.335 ± 100 AU). La tolerancia al estrés disminuyó durante la sobrecarga (4,0 ± 0,7; 8,2 ± 1,3; 10,1 ± 1,4) y aumentó durante la última semana (5,5 ± 1,5). Además, las altas cargas del entrenamiento interno durante la sobrecarga resultaron en una gran reducción en la diferencia de la raíz cuadrada media de intervalos R-R sucesivos (lnRMSSDmean) (4,2 ± 0,2; 4,1 ± 0,1; 4,0 ± 0,1 ms) y un coeficiente de variación más pequeño (lnRMSSDcv) (4,5 ± 2,6; 2,1 ± 1,2; 1,4 ± 0,9 %), y la reducción significativa en la carga de entrenamiento interno durante la última semana(AU)

Novel track field test to determine Vpeak, relationship with treadmill test and 10-km running performance in trained endurance runners.

OBJECTIVES: The aim of this study was to determine the peak running velocity on the track field (Vpeak_TF) based on the laboratory treadmill test (Vpeak_T), and relate the Vpeak values as well as their correlation with the 10-km running performance in trained endurance runners. METHOD: Twenty male trained endurance runners (age: 29.5 ± 5.3 years; V̇O2max: 67.5±17.6 ml · kg-1·min-1) performed three maximum incremental tests to determine the Vpeak: one for Vpeak_T determination and two to obtain Vpeak_TF on the official track field (400 m), and a 10-km running performance. During the incremental tests, maximum heart rate (HRmax), maximal rating of perceived exertion (RPEmax), and peak lactate concentration (LApeak) were determined. RESULTS: The results showed significant difference between the Vpeak_TF and Vpeak_T (18.1 ± 1.2 vs. 19.2 ± 1.5 km·h-1, respectively), as well as the total time of the tests, the distance traveled and the RPEmax determined during the tests. A high correlation was observed between the Vpeak values (r = 0.94), and between Vpeak_TF and Vpeak_T with 10-km running performance (r = -0.95 vs. r = -0.89, respectively). CONCLUSIONS: The good agreement and association with Vpeak_T and high correlation with 10-km running performance demonstrate that the novel track field test is efficient for Vpeak_TF determination.

Does isolated and combined acute supplementation of caffeine and carbohydrate feeding strategies modify 10-km running performance and pacing strategy? A randomized, crossover, double-blind, and placebo-controlled study / La suplementación aguda, aislada y combinada de cafeína y carbohidratos como estrategias de alimentación cambia el rendimiento y un ritmo de carrera de 10-km? Un estudio aleatorizado, cruzado, doble ciego, controlado con placebo

Background: Long distance practice running are growing and nutritional ergogenic are commonly used as a potential aidin final training and competition performance. Caffeine (CAF) and carbohydrates (CHO) are among the most commonly usedsupplements due to their expected ergogenic properties that can optimize energetic systems. The objective of this study was toexamine potential changes in 10-km running performance with acute isolated and combined CAF and CHO supplementation.Material and method: Fifteen recreational endurance-trained runners performed four 10-km running performance on anofficial athletic track (400 m) under four supplementation conditions: placebo and placebo (PLA+PLA), placebo and caffeine(PLA+CAF), placebo and carbohydrates (PLA+CHO), caffeine and carbohydrates (CAF+CHO). CAF and CHO supplementationconsisted of capsules of 6 mg·kg-1 and 8% CHO solution (1 g·kg-1) respectively, ingested 60 and 30 minutes before the perfor-mance tests. Placebo was obtained through empty capsules for CAF and juice for CHO without sugar (Clight®). During eachtrial running speed to calculate 10-km mean velocity (MV) and maximum heart rate (HRmax) were analyzed.Results: There was a difference in the pacing strategy adopted by the runners with higher MV during the initial phase forPLA+CAF and CAF+CHO groups and in the final phase for PLA+ CHO. However, there was no statistically significant differencein 10-km running performance between the conditions, as well as for HRmax.Conclusions: The use of acute, isolated and combined CAF+CHO supplementation had influence in the pacing strategy, butno in 10- km final performance, of recreational runners.(AU)

Introducción: Las carreras de larga distancia están creciendo y los ergógenos nutricionales se usan comúnmente como unaayuda potencial en el entrenamiento final y el rendimiento en competición. La cafeína (CAF) y los carbohidratos (CHO) seencuentran entre los suplementos más utilizados debido a sus propiedades ergogénicas que pueden optimizar los sistemasenergéticos. El objetivo de este estudio fue examinar posibles cambios en el rendimiento de carrera de 10-km con suplemen-tación aislada aguda y combinada de CAF y CHO.Material y método: Quince corredores recreativos realizaron cuatro carreras de 10-km en una pista deportiva oficial(400 m) bajo cuatro condiciones de suplementación: placebo y placebo (PLA + PLA), placebo y cafeína (PLA + CAF), placeboy carbohidratos (PLA + CHO), cafeína y carbohidratos (CAF + CHO). La suplementación con CAF y CHO consistió en cápsulasde 6 mg·kg-1 y solución de CHO al 8% (1 g·kg-1) respectivamente, ingeridas 60 y 30 minutos antes de las carreras. El placebose obtuvo usando cápsulas de CAF vacías y jugo sin azúcar para CHO (Clight®). Durante cada carrera, se analizó la velocidadde carrera para calcular la velocidad promedio de 10-km (VP) y la frecuencia cardíaca máxima (FCmáx).Resultados: Hubo una diferencia en la estrategia de carrera adoptada por los corredores con la VP más alta durante la faseinicial para los grupos PLA + CAF y CAF + CHO y en la fase final para PLA + CHO. No hubo diferencias estadísticamente signi-ficativas en el rendimiento de carrera de 10-km entre las condiciones, así como en la FCmáx.Conclusiones: El uso de suplementos agudos, aislados y combinados de CAF + CHO influyó en la estrategia de carrera, perono en el rendimiento final de 10-km en corredores recreativos.(AU)

Effect of Photobiomodulation on Critical Swimming Velocity: A Randomized, Crossover, Double-Blind, and Placebo-Controlled Study.

PURPOSE: To analyze the acute effect of photobiomodulation (PBM) on swimming critical velocity (CV). METHODS: A total of 15 male federated swimmers (20.9 [2.4] y old) participated in this study. Three sets of front crawl were performed at distances of 100, 200, and 400 m to determine the CV under 3 experimental conditions: PBM (420 J), placebo (PLA), and control (C) in this randomized, crossover, double-blind, and placebo-controlled study. One-way analysis of variance for repeated measurements was used for statistical analyses. RESULTS: The results showed that the prior application of PBM did not have ergogenic effects on CV and front crawl swimming performance: CV (PBM = 1.15 [0.15]; PLA = 1.20 [0.25]; C = 1.15 [0.14] m·s-1), swim time (ST) 100 m (PBM = 65.5 [6.3]; PLA = 65.2 [5.6]; C = 66.0 [5.9] s), ST 200 m (PBM = 148.5 [17.9]; PLA = 149.4 [16.4]; C = 150.1 [17.9] s), and ST 400 m (PBM = 327.7 [38.2]; PLA = 321.6 [47.7]; C = 329.5 [41.2] s). CONCLUSIONS: A PBM application prior to front crawl swimming test did not significantly modify the CV, ST, physiological factors of metabolic fatigue, perceptual, and front crawl stroke efficiency parameters in competition swimmers covering distances of 100, 200, and 400 m.

Time limit at peak speed without prior warm-up: Effects on test duration, heart rate and rating of perceived exertion / Tiempo límite en la velocidad máxima sin calentamiento previo: efectos sobre la duración de la prueba, frecuencia cardíaca y grado de esfuerzo percibido

Background: Time limit (tlim) at peak speed (Vpeak), that is maximal time that an individual can keep running at maximal intensity, is used to prescribe interval durations during interval training. The aim of this study was to compare two protocols (without or with 15 minutes of warm-up) for the tlim determination at 100% of Vpeak in untrained men. Material and method: Twelve untrained young men performed three running tests on a treadmill: one maximal incremental test to determine Vpeak and two rectangular tests, performed in randomized order, without a warm-up (tlim0) or with a 15-minute warm-up duration (tlim15) at 60% of Vpeak to determine the tlim at 100% of Vpeak, after the warm-up the tests were performed at the speed of the individual Vpeak until volitional exhaustion. During the tests, heart rate (HR) and rating of perceived exertion (RPE) were monitored and blood lactate sampling was collected prior to session (LApre); immediately post-exercise (LA0-min); 3 min (LA3-min), 5 min (LA5-min) and 7 min (LA7-min) post-exercise to determine lactate concentrations. The Shapiro-Wilk test was used and confirmed the normality of the data distribution, with maximal and submaximal values compared using Student ́s t test for dependent samples. Results: Test duration at tlim0 was significant higher than that at tlim15 (P = 0.02). Additionally, different tlim protocols influenced HR and RPE submaximal responses and did not modify lactate concentrations or maximal variables (HRmax and RPEmax). Conclusions: These findings suggest that the determination of tlim at 100% of Vpeak without a prior warm-up led to a higher test duration in untrained men

Objetivos: Tiempo límite (tlim) en la velocidad máxima (Vpico), que es el tiempo máximo que un individuo puede permanecer corriendo en la intensidade máxima, se utiliza para prescribir la duración de los intervalos durante el entrenamiento interválico. El objetivo de este estudio fue comparar dos protocolos (sin o con 15 minutos de calentamiento) para la determinación de tlim al 100% de la Vpico en hombres no entrenados. Material y método: Doce jóvenes no entrenados realizaron tres pruebas de carrera en la cinta rodante: una prueba incremental máxima para determinar Vpico y dos pruebas rectangulares, realizadas en orden aleatorio, sin calentamiento (tlim0) o con una duración de calentamiento de 15 minutos (tlim15) al 60% de la Vpico para determinar el tlim al 100% de la Vpico; después del calentamiento las pruebas fueron realizadas en la velocidad de la Vpico individual hasta el agotamiento voluntario. Durante las pruebas, la frecuencia cardíaca (FC) y el grado de esfuerzo percibido (RPE) fueron monitorizadas y se tomaron muestras de sangre antes de la sesión (LApre); inmediatamente después del ejercicio (LA0-min); 3 min (LA3-min), 5 min (LA5-min) y 7 min (LA7-min) después del ejercicio para determinar las concentraciones de lactato. Se utilizó la prueba de Shapiro Wilk y se confirmó la normalidad de la distribución de los datos, con los valores máximos y submáximos comparados utilizando la prueba t de Student para muestras dependientes. Resultados: La duración de la prueba en el tlim0 fue significativamente mayor que aquella en el tlim15 (P = 0.02). Además, los diferentes protocolos de tlim influenciaron las respuestas submáximas de FC y RPE y no modificaron las concentraciones de lactato o las variables máximas (FCmax y RPEmax). Conclusiones: Estos resultados sugieren que la determinación del tlim en la 100% de la Vpico sin calentamiento prévio lleva a una mayor duración de la prueba em hombres no entrenados

Endurance Running Training Individually Guided by HRV in Untrained Women.

da Silva, DF, Ferraro, ZM, Adamo, KB, and Machado, FA. Endurance running training individually guided by HRV in untrained women. J Strength Cond Res 33(3): 736-746, 2019-The aim of this study was to analyze the effects of heart rate variability (HRV)-guided training compared with a standardized prescription on (a) time to complete 5-km running performance (t5km), (b) peak treadmill running speed (Vpeak) and its time limit (tlim at Vpeak), and (c) autonomic cardiac modulation (i.e., parasympathetic activity and recovery) in untrained women. Additionally, we correlated changes in t5km with changes in Vpeak, tlim at Vpeak and autonomic cardiac modulation. Thirty-six untrained women were divided into a HRV-guided training group (HRVG) and a control group (CG). The CG followed a predefined program, alternating moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT). The determination of MICT or HIIT was based on the pretraining HRV for HRVG. MICT was performed if HRV was

Peak Velocity as an Alternative Method for Training Prescription in Mice.

Purpose: To compare the efficiency of an aerobic physical training program prescribed according to either velocity associated with maximum oxygen uptake (vVO2max) or peak running speed obtained during an incremental treadmill test (Vpeak_K) in mice. Methods: Twenty male Swiss mice, 60 days old, were randomly divided into two groups with 10 animals each: 1. group trained by vVO2max (GVO2), 2. group trained by Vpeak_K (GVP). After the adaptation training period, an incremental test was performed at the beginning of each week to adjust training load and to determine the amount of VO2 and VCO2 fluxes consumed, energy expenditure (EE) and run distance during the incremental test. Mice were submitted to 4 weeks of aerobic exercise training of moderate intensity (velocity referring to 70% of vVO2max and Vpeak_K) in a programmable treadmill. The sessions lasted from 30 to 40 min in the first week, to reach 60 min in the fourth week, in order to provide the mice with a moderate intensity exercise, totaling 20 training sessions. Results: Mice demonstrated increases in VO2max (ml·kg-1·min-1) (GVO2 = 49.1% and GVP = 56.2%), Vpeak_K (cm·s-1) (GVO2 = 50.9% and GVP = 22.3%), EE (ml·kg-0,75·min-1) (GVO2 = 39.9% and GVP = 51.5%), and run distance (cm) (GVO2 = 43.5% and GVP = 33.4%), after 4 weeks of aerobic training (time effect, P < 0.05); there were no differences between the groups. Conclusions: Vpeak_K, as well as vVO2max, can be adopted as an alternative test to determine the performance and correct prescription of systemized aerobic protocol training to mice.

Effect of prior warm-up duration on the time limit at peak speed in untrained men.

BACKGROUND: The peak speed (Vpeak) and its time limit (tlim) are variables used to prescribe training loads and the intervals durations during interval training, respectively. The aim of this study was to test different warm-up durations (5, 10 and 15 minutes), adapted from the protocol proposed by Billat et al.,1 to determine tlim in untrained men. METHODS: Fifteen untrained men were submitted to the following laboratory evaluations: 1) an incremental running exercise test on a treadmill starting with a speed of 8 km/h, after a warm-up of walking at 6 km/h for three minutes, and increased by 1 km/h between each successive 3-minute stage until volitional exhaustion to determine Vpeak; 2) three rectangular tests, performed in randomized order, with warm-up durations of 5, 10, and 15 minutes at 60% of Vpeak to determine the tlim5, tlim10, and tlim15; after the warm-up the tests were performed at the speed of the individual Vpeak until volitional exhaustion. RESULTS: It was demonstrated that the duration of the warm-up affected the test duration (tlim). Significant differences were observed between tlim5 and tlim15, and between tlim10 and tlim15. However, tlim15 and tlim10 did not differ. Additionally, duration of the warm-up did not influence other variables (HRmax, RPEmax and post lactate concentrations). CONCLUSIONS: Therefore, it was concluded that the duration of the warm-up in tlim tests modifies the test duration in untrained men.

Effects of ceramic garments on 10-km running performance

Aims: The use of electromagnetic waves by phototherapy to skeletal muscle presents potential ergogenic effects. The aim of this study was to analyze the effect of using bioceramic clothes on performance, heart rate (HR) and rating of perceived exertion (RPE) during a 10 km race. Our hypothesis is that the use of such clothes modifies these variables. Methods: Participants were 10 runners (27.9 ± 4.2 years) who performed two 10 km performances on track under different intervention conditions: bioceramic garments (CER) and placebo garments (PLA). The mean velocity (MV), HR and rate of perceived exertion (RPE) were monitored at each trial. Additionally, partial MV was calculated in three phases: (1) start (first 400 m), (2) middle (400-9600 m) and (3) end (last 400 m). Results: MV in CER condition was significantly higher than in PLA condition (11.8 ± 1.0 km·h-1 vs 11.4 ± 1.2 km·h-1; F = 6.200; P = 0.034; ŋp² = 0.408). HR and RPE values in CER condition were not different from PLA condition. Conclusions Our main finding was that the use of bioceramic clothes (CER) increased MV when compared to the PLA condition. Based on these results, bioceramic may be used as an ergogenic resource to increase performance.(AU)

Comparison between lactate minimum and critical speed throughout childhood and adolescence in swimmers.

This study aimed to examine the influence of age and degree of maturity on the comparison and relationship between lactate minimum intensity (LM) and critical speed (CS) throughout childhood and adolescence in swimmers. Forty-six male swimmers aged between 10 and 18 years were divided into three age groups according to pubertal stages and training status. Maximal efforts of 100 and 400 m and the LM protocol with 200 m performances were executed. CS was determined with a 3-distances combination (100, 200, and 400 m). One-way and mixed analysis of variance for repeated measures, Bland-Altman, Pearson correlation, percentage difference, and effect size were used to compare and examine the relationship between variables in each age group. The results revealed that LM and CS had differences in comparison with one another throughout childhood and adolescence in swimmers, because CS clearly underestimated LM in the 10 to 12.6-year age group, while overestimating it in the 15.4 to 18-year age group of swimmers. Thus, coaches and swimmers must be aware of the age-dependency of CS for indices of aerobic endurance measurements in the initial ages of systematized swimming training.

Effect of age, anthropometry, and distance in stroke parameters of young swimmers.

This study aimed to determine the influence of age, anthropometry, and distance on stroke parameters of 10- to 17-y-old swimmers. Forty-six male swimmers were divided into 4 chronological age groups. Anthropometry and sexual maturity were assessed, and maximal efforts of 100, 200, and 400 m using front-crawl style were performed to determine stroke rate (SR), length (SL), and index (SI). Multiple linear regression, 1-way, and mixed ANOVA for repeated measures were used for statistical analyses. There was significant effect of distance for all stroke parameters (P < .001) and an age effect only for SL and SI (P < .001). Post hoc showed that the 10- to 17-year-old group significantly reduced SR with increasing distance (effect size -0.8 to -1.5 comparing 100, 200, and 400 m) but were not effective in offsetting this adaptation with increased SL, especially from 200- to 400-m distance, at which no group made both adjustments, highlighting the decreased efficiency with significant SI reduction (effect size -0.2 to -0.4 comparing 100, 200, and 400 m). Considering all stroke parameters, the performances were almost 100% explained, but SI itself could explain around 90% of the performance; furthermore, limb length contributed to explain all stroke parameter, and SI was the variable best predicted (around 75%) by anthropometrical (upper limbs and height) and descriptive variables (age and y of systematic training).Thus, distinct effects of distance and advancing age were found during childhood and adolescence on stroke parameters, and SI was highlighted as the best predictor of 100-, 200-, and 400-m maximal performances.

Physiological and Technical-tactical Analysis in Brazilian Jiu-jitsu Competition.

PURPOSE: The present study aims at investigating the physiological response and technical-tactical parameters in Brazilian jiu-jitsu competition. METHODS: The study included 35 male Brazilian jiu-jitsu athletes (adult category, body mass: 80.2 ± 13.0 kg), graded from white to brown belt, during combats fought at regional level. Twenty-two fights were analyzed in terms of technique and time structure. Blood glucose, lactate and maximal isometric grip strength were determined before and after the fights. The rate of perceived exertion was also assessed after the fight, using the 6-20 Borg rating. The fights were recorded and the following variables were determined: the exertion/pause ratio and subjective intensity of actions, categorized between low and high intensity. RESULTS: The results indicated that during Brazilian jiu-jitsu fights, the glycolytic pathway is only moderately activated (lactate before: 4.4 (4.0 - 4.6) mmol/L, after: 10.1 (8.0 - 11.3) mmol/L; glucose before: 112.4 ± 22.3 mg/dL, after: 130.5 ± 31.0 mg/dL). The exertion during the fight resulted in significant reductions in handgrip strength (right hand grip before: 45.9 ± 10.3 kgf, after: 40.1 ± 9.5 kgf; left hand grip before: 44.2 ± 11.1 kgf, after: 37.0 ± 10.2 kgf). The athletes rated the fight as hard: 15 (13 - 15). Effort/pause ratio was 6:1, while high-intensity actions lasted approximately 4 s, resulting in a low/high intensity? ratio of 8:1. CONCLUSION: It is recommended that coaches direct the training loads to simulate the energy demand imposed by the competitive matches, activating moderately the glycolytic pathway. Moreover, the time structure of combats can be used to prescribe both physical and technical-tactical training.

Incremental test design, peak 'aerobic' running speed and endurance performance in runners.

OBJECTIVES: Peak running speed obtained during an incremental treadmill test (Vpeak) is a good predictor of endurance run performance. However, the best-designed protocol for Vpeak determination and the best Vpeak definition remain unknown. Therefore, this study examined the influence of stage duration and Vpeak definition on the relationship between Vpeak and endurance run performance. DESIGN: Relationship. METHODS: Twenty-seven male, recreational, endurance-trained runners (10-km running pace: 10-17 k mh(-1)) performed, in counterbalanced order, three continuous incremental treadmill tests of different stage durations (1-, 2-, or 3-min) to determine Vpeak, and two 5-km and two 10-km time trials on a 400-m track to obtain their 5-km and 10-km run performances. Vpeak was defined as either (a) the highest speed that could be maintained for a complete minute (Vpeak-60 s), (b) the speed of the last complete stage (Vpeak-C), or (c) the speed of the last complete stage added to the multiplication of the speed increment by the completed fraction of the incomplete stage (Vpeak-P). RESULTS: The Vpeak determined during the 3-min stage duration protocol was the most highly correlated with both the 5-km (r=0.95) and 10-km (r=0.92) running performances and these relationships were minimally influenced by the Vpeak definition. However, independent of the stage duration, the Vpeak-P provided the highest correlation with both running performances. CONCLUSIONS: Incremental treadmill tests comprising 3-min stage duration is preferred to 1-min and 2-min stage duration protocols in order to determine Vpeak to accurately predict 5-km and 10-km running performances. Further, Vpeak-P should be used as standard for the determination of Vpeak.

Effect of stage duration on maximal heart rate and post-exercise blood lactate concentration during incremental treadmill tests.

OBJECTIVES: This study compared the responses during maximal incremental treadmill tests of 1-min, 2-min, and 3-min stage durations mainly in terms of maximal heart rate (HRmax) and peak blood lactate concentration (LApeak). DESIGN: Repeated-measures. METHODS: Thirty-four male, recreational, endurance-trained runners (40±13 years) performed three tests on a motorized treadmill. The tests started at 8kmh(-1) with increments of 1kmh(-1) every 1min for the short-stage protocol, every 2min for the intermediate-stage protocol, and every 3min for the long-stage protocol. LApeak was defined for each subject as the highest value among the lactate concentrations determined at the end of each test and at the third, fifth and seventh minutes after test, during passive recovery. RESULTS: Analysis of variance revealed a significant effect of the stage duration on the HRmax (p=0.003) and LApeak (p=0.001). The HRmax was higher in the intermediate-stage compared to the short-stage protocol (184.8±12.7 vs. 181.8±12.1beatsmin(-1), p<0.001), but no significant differences were found between the long-stage (183.1±12.1beatsmin(-1)) and the intermediate-stage or short-stage protocols (p>0.05). The LApeak was lower in the long-stage compared to the short-stage and intermediate-stage protocols (7.9±2.2 vs. 9.4±2.2 and 9.2±1.9mmolL(-1), respectively, p<0.05). Further, blood lactate reached peak concentration at the fifth minute after test for all the protocols. CONCLUSIONS: Thus, HRmax and LApeak depend on the stage duration of the incremental test, but the moment at which blood lactate reaches peak concentration is independent of the duration. Further, we suggest 2-min stage duration protocols to determine HRmax.

Indirect determination of lactate minimum speed from a single maximal performance in young swimmers.

This study aimed to generate equations for the indirect determination of lactate minimum (LM) intensity from short-distance maximal performances in 10- to 17-year-old swimmers. Seventy-one male (n = 41) and female (n = 30) competitive swimmers were divided into subgroups: one to generate predictive equations for LM (~70% of the sample), and the second to cross-validate the proposed equations (~30% of the sample). All participants swam maximally short-distance using front crawl stroke, and mean speed of the 100 (S100), 200 (S200), and 400 m (S400) performances were calculated in m·s(-1). The LM protocol was measured after an 8 min of passive recovery from the S200, consisting of five progressive 200 m performances (~80%, 84%, 88%, 92%, and 96% of S200). Multiple linear regressions generated predictive equations for LM from single performances (S100, S200, and S400), also considering as independent variables age, pubic hair index, body mass, height, and body fat. The relationships between variables were examined using standard error of estimate (SEE). Nevertheless, age, biological maturation and anthropometric variables did not contribute to explain LM. Further, for both genders, S200 was the best predictor for LM, contributing to 95% of LM variation in males and 81% in females. The generated equations were: "LM = 0.24 + 0.67 × S200" (adjusted R(2) = 0.95; SEE = 0.03 m·s(-1)) for boys and "LM = 0.13 + 0.79 × S200" (adjusted R(2) = 0.81; SEE = 0.03 m·s(-1)) for girls. The predicted LM did not differ from the measured LM during cross-validation analysis. A single performance was found to be a valid LM predictor in 10- to 17-year-old swimmers regardless of gender, age and biological maturation. Thus, this is a practical, non-invasive, and economical alternative to estimate the aerobic capacity in young swimmers. Key PointsLM can be estimated from a single maximal swimming performance for boys and girls, regardless age, sexual maturity, anthropometrical and body composition parameters.For boys, S200 was the best LM predictor (LM = 0.24 + 0.67 x S200), explaining 95% of LM variation with great cross validation parameters.For girls, S200 was also the best LM predictor (LM = 0.13 + 0.79 x S200), explaining 81% of LM variation with great cross validation parameters.

Effects of exercise mode on the oxygen uptake kinetic response to severe-intensity exercise in prepubertal children.

The objective of this study was to verify the effect of the exercise mode on slow component of VO2 (VO2SC) in children aged 11-12 years during severe-intensity exercise. After determination of the lactate threshold (LT) and peak VO2 (VO2peak) in both cycling (CE) and running exercise (TR), fourteen active boys completed a series of "square-wave" transitions of 6-min duration at 75 delta [75% delta = LT + 0.75 3 (VO2peak--LT)] to determine the VO2 kinetics. The VO2SC was significantly higher in CE (180.5 +/- 155.8 ml x min-1) than in TR (113.0 +/- 84.2 ml x min-1). We can conclude that, although a VO2SC does indeed develop during TR in children, its magnitude is considerably lower than in CE during severe-intensity exercise.