Fábio Yuzo Nakamura

Influência do processo de familiarização para avaliação da força muscular em testes de 1-RM

RESUMENInfluencia del proceso de familiarizacion para evaluacion de lafuerza muscular en tests de 1-RM Embora la utilizacion de tests de una repeticion maxima (1-RM)es frecuente para la evaluacion de la fuerza muscular, se acreditaque los resultados obtenidos puedan ser afectados por la falta defamiliarizacion previa, hasta mismo en sujetos con experiencia enejercicios con pesos. Asi, el objetivo de este estudio fue investigarel impacto del proceso de familiarizacion para evaluacion de la fuerzamuscular en tests de 1-RM. Por lo tanto, 21 hombres (24,5 ± 3,8anos), aparentemente saludables con experiencia previa de por lomenos seis meses de entrenamiento con pesos, fueron someti-dos a tests reptitivos de 1-RM en los ejercicios supino en bancohorizontal, agachamiento y rosca directa de biceps. Los tests fue-ran ejecutados en cuatro sesiones, intervaladas en cada 48-72 ho-ras. Un numero maximo de tres tentativas, con intervalo de tres acinco minutos para recuperacion, fue utilizado en cada ejercicio,en las cuatro sessiones de testeo. ANOVA se utilizo para medidasrepetidas, seguida por el test post hoc de Tukey, cuando p ≤ 0,05,fue utilizada para el tratamiento de los datos. Aumentos significan-tes en la fuerza muscular (p ≤ 0,01) fueron encontrados los tresejercicios analizados entre la primera y la cuarta sesion de familia-rizacion (2,4% en supino en banco horizontal, 3,4% en agacha-miento y 5,4% en la rosca directa del biceps). Todavia, ningunadiferencia estadisticamente significativamente fuera encontradaentre la segunda y la cuarta sesion de familiarizacion en la roscadirecta de biceps (p > 0,05), bien con entre la tercera y la cuartasesion en el supino en el banco horizontal y en el agachamiento ( p> 0,05). Los resultados indican que la falta de familiarizacion previacon tests de 1-RM puede comprometer la evaluacion de la fuerzamuscular. Por lo tanto, se sugiere para la evaluacion mas acuradade la fuerza muscular mediante tests de 1-RM la ejecucion de dosa tres sesiones de familiarizacion en los hombres adultos con ex-periencia en ejercicios con pesos.Although the use of maximum repetition tests (1-RM) is frequent for assessment of the muscular strength, one believes that the results obtained may be affected by the lack of previous familiarization, even in skilled subjects in exercises with weights. Thus, the objective of this study was to investigate the impact of the familiarization process on the muscular strength assessment in 1-RM tests. To do so, 21 men (24.5 ± 3.8 years of age), apparently healthy and with previous experience of at least six months on weight training, were submitted to repetitive tests of 1-RM in bench press, squat, and arm curl exercises. The tests were performed in four sessions with intervals every 48-72 hours. A maximum number of three attempts with 3-5 minutes interval for recovery was used in each exercise in the four testing sessions. The analysis of variance ANOVA for repeated measures followed by the post hoc Tukey test when p 0.05) as well as between the third and fourth sessions in the bench press and squat (p > 0.05). The results indicate that the lack of previous familiarization with 1-RM tests may impair the muscular strength evaluation. Therefore, the performance of two to three familiarization sessions in adult men with previous experience with weightlifting is suggested for a more accurate muscular strength assessment by means of the 1-RM tests.

Noninvasive method to estimate anaerobic threshold in individuals with type 2 diabetes

BackgroundWhile several studies have identified the anaerobic threshold (AT) through the responses of blood lactate, ventilation and blood glucose others have suggested the response of the heart rate variability (HRV) as a method to identify the AT in young healthy individuals. However, the validity of HRV in estimating the lactate threshold (LT) and ventilatory threshold (VT) for individuals with type 2 diabetes (T2D) has not been investigated yet.AimTo analyze the possibility of identifying the heart rate variability threshold (HRVT) by considering the responses of parasympathetic indicators during incremental exercise test in type 2 diabetics subjects (T2D) and non diabetics individuals (ND).MethodsNine T2D (55.6 ± 5.7 years, 83.4 ± 26.6 kg, 30.9 ± 5.2 kg.m2(-1)) and ten ND (50.8 ± 5.1 years, 76.2 ± 14.3 kg, 26.5 ± 3.8 kg.m2(-1)) underwent to an incremental exercise test (IT) on a cycle ergometer. Heart rate (HR), rate of perceived exertion (RPE), blood lactate and expired gas concentrations were measured at the end of each stage. HRVT was identified through the responses of root mean square successive difference between adjacent R-R intervals (RMSSD) and standard deviation of instantaneous beat-to-beat R-R interval variability (SD1) by considering the last 60 s of each incremental stage, and were known as HRVT by RMSSD and SD1 (HRVT-RMSSD and HRVT-SD1), respectively.ResultsNo differences were observed within groups for the exercise intensities corresponding to LT, VT, HRVT-RMSSD and HHVT-SD1. Furthermore, a strong relationship were verified among the studied parameters both for T2D (r = 0.68 to 0.87) and ND (r = 0.91 to 0.98) and the Bland & Altman technique confirmed the agreement among them.ConclusionThe HRVT identification by the proposed autonomic indicators (SD1 and RMSSD) were demonstrated to be valid to estimate the LT and VT for both T2D and ND.

Seasonal Changes in Physical Performance and Heart Rate Variability in High Level Futsal Players

The aim of this study was to determine the changes in physical performance and resting heart rate variability (HRV) in professional futsal players during the pre-season and in-season training periods. 11 athletes took part in the study (age=24.3±2.9 years; height=176.3±5.2 cm; weight=76.1±6.3 kg), and performed a repeated-sprint ability (RSA) test [6×40 m (20+20 m with a 180° change of direction) sprints separated by 20 s of passive recovery] and Yo-Yo intermittent recovery test level 1 (Yo-Yo IR1) at 3 different moments (M1=beginning of pre-season; M2=end of pre-season; M3=mid in-season). The HRV indices were assessed at the same moments. After the short pre-season (3-week), mean RSA time (RSAmean) (M1=7.43±0.2 s; M2=7.24±0.2 s; P=0.003), decrement in RSA performance (RSAdecrement) (M1=6.7±0.3%; M2=5.0±0.9%; P=0.001), and Yo-Yo IR1 distance (M1=1.244±298 m; M2=1.491±396 m; P=0.002) were significantly improved (P<0.05). During the in-season (i. e., M3), performance in Yo-Yo IR1 and RSAmean were maintained. In contrast, RSAbest (M2=6.89±0.2 to M3=6.69±0.3; P=0.001) was improved and RSAdecrement (M2=5.0±0.9% to M3=6.6±0.9%; P=0.001) was impaired. At M2, there was an increase in HRV vagal-related indices compared with M1 that was maintained at M3. In conclusion, after a short pre-season, futsal players improved their RSA and Yo-Yo IR1 performance with concomitant improvements in HRV. These indices were maintained during the in-season period while RSAbest was improved and RSAdecrement impaired. Frequent monitoring of these performances and HRV indices may assist with identification of individual training adaptations and/or early signs of maladaption.

Impacto de oito semanas de treinamento com pesos sobre a força muscular de homens e mulheres

O objetivo do presente estudo foi verificar o impacto de oito semanas de treinamento com pesos (TP) sobre a forca muscular. Para tanto, 23 homens (20,7 ± 1,7 anos) e 15 mulheres (20,9 ± 2,1 anos), aparentemente saudaveis e moderadamente ativos (atividade fisica regular < 2 vezes por semana), foram submetidos a um programa de TP composto por 10 exercicios para os diferentes grupos musculares durante oito semanas consecutivas. Tres series de 8-12 RM foram executadas em cada exercicio, em tres sessoes semanais intervaladas a cada 48 horas. A forca muscular foi determinada pre e pos-treinamento por meio de testes de 1-RM nos exercicios supino em banco horizontal, agachamento e rosca direta de biceps, apos cinco sessoes de familiarizacao. Aumentos na forca muscular foram identificados, em ambos os sexos, nos tres exercicios investigados, bem como no somatorio da carga total levantada (P < 0,01). Apesar de os homens apresentarem forca absoluta maior do que as mulheres em todos os exercicios analisados, os ganhos observados ao longo do tempo foram maiores no sexo feminino (14,7 vs. 7,6% no agachamento; 17,2 vs. 11,0% no supino em banco horizontal; 20,4 vs. 14,0% na rosca direta de biceps). Os resultados sugerem que o periodo de oito semanas de TP parece ser suficiente para promover modificacoes significantes na forca muscular de homens e mulheres, em diferentes segmentos corporais (membros inferiores, tronco e membros superiores).The objective of the present study was to verify the impact of an eight-week weight training program (WT) on the muscular strength. To do so, 23 men (20.7 ± 1.7 years) and 15 women (20.9 ± 2.1 years), apparently healthy and moderately active (regular physical activity < 2 times a week) were submitted to a WT program composed of 10 exercises for the different muscular groups during eight consecutive weeks. Three series of 8-12 RM were performed in each exercise in three weekly sessions with intervals each 48 hours. The pre and post-training muscular strength was determined by means of 1-RM tests in bench press, squat and arm curl exercises after five familiarization sessions. Increases on the muscular strength were verified in both genders in all exercises investigated as well as in the total amount of load lifted (P < 0.01). Although men presented higher absolute strength when compared to women in all exercises evaluated, the gains observed along time were higher for women (14.7 vs. 7.6% in squat; 17.2 vs. 11.0% bench press; 20.4 vs. 14.0% in arm curl). The results suggest that the eight-week WT period seems to be sufficient to promote significant modifications in the muscular strength of men and women in different body segments (lower limbs, trunk and upper limbs).

Effects of preferred and nonpreferred music on continuous cycling exercise performance.

The aim of this study was to investigate the effects of preferred and nonpreferred music on exercise distance, Heart Rate (HR), and Rating of Perceived Exertion (RPE) during continuous cycling exercise performed at high intensity. Fifteen participants performed five test sessions. During two sessions, they cycled with fixed workload on ergometer to determine the Critical Power (CP) intensity. Then, they performed three more sessions cycling at CP intensity: listening to Preferred Music, listening to Nonpreferred Music, and No Music. The HR responses in the exercise sessions did not differ among all conditions. However, the RPE was higher for Nonpreferred Music than in the other conditions. The performance under Preferred Music (9.8 ± 4.6km) was greater than under Nonpreferred Music (7.1 ± 3.5km) conditions. Therefore, listening to Preferred Music during continuous cycling exercise at high intensity can increase the exercise distance, and individuals listening to Nonpreferred Music can perceive more discomfort caused by the exercise.

Cardiac autonomic responses to repeated shuttle sprints.

Team sport match play requires athletes to perform a number of repeated shuttle sprints. However, the acute effects of these repeated sprint sequences on lactic acidosis and resulting autonomic state perturbation are not known. The aim of this study was to observe and compare the blood lactate and post-exercise cardiac autonomic responses of a repeated shuttle-sprint ability test with the 30-15 Intermittent Fitness Test (30-15 (IFT)); the latter test representing a standard for exhaustive supramaximal effort. Thirteen adult team sport players performed the repeated shuttle-sprint ability test and the 30-15 (IFT) on separate days in a counter-balanced order. The repeated shuttle-sprint ability test consisted of six repetitions of maximal 2x15 m shuttle sprints ( approximately 5 s) departing every 20 s, while the 30-15 (IFT) involved progressive 30 s shuttle runs interspersed with 15 s of passive recovery until exhaustion. Blood lactate was measured before and after the tests, while autonomic responses were assessed using immediate heart rate recovery and heart rate variability indices. Peak blood lactate (10.6+/-2.1 vs. 10.2+/-2.8 mM) and heart beats recovered in one minute after exercise cessation (36.4+/-7.8 vs. 39.3+/-7.9 bpm) were similar after both the repeated shuttle-sprint ability test and the 30-15 (IFT). With the exception of the vagal-related time-varying root mean square of successive R-R interval differences at each 30 s, which recovered earlier after the repeated shuttle-sprint ability test compared with 30-15 (IFT), all heart rate variability indices decreased similarly after both tests in comparison to baseline values. In conclusion, the repeated shuttle-sprint ability test was shown to induce comparable levels of lactic acidosis and post-exercise autonomic state as the 30-15 (IFT). These levels of metabolic and autonomic states are likely to occur during team sport match play.

Effect of carbohydrate availability on time to exhaustion in exercise performed at two different intensities

This study examined the effects of pre-exercise carbohydrate availability on the time to exhaustion for moderate and heavy exercise. Seven men participated in a randomized order in two diet and exercise regimens each lasting 3 days with a 1-week interval for washout. The tests were performed at 50% of the difference between the first (LT1) and second (LT2) lactate breakpoint for moderate exercise (below LT2) and at 25% of the difference between the maximal load and LT2 for heavy exercise (above LT2) until exhaustion. Forty-eight hours before each experimental session, subjects performed a 90-min cycling exercise followed by 5-min rest periods and a subsequent 1-min cycling bout at 125% VO2max/1-min rest periods until exhaustion to deplete muscle glycogen. A diet providing 10% (CHO(low)) or 65% (CHO(mod)) energy as carbohydrates was consumed for 2 days until the day of the experimental test. In the exercise below LT2, time to exhaustion did not differ between the CHO(mod) and the CHO(low) diets (57.22 +/- 24.24 vs 57.16 +/- 25.24 min). In the exercise above LT2, time to exhaustion decreased significantly from 23.16 +/- 8.76 min on the CHO(mod) diet to 18.30 +/- 5.86 min on the CHO(low) diet (P < 0.05). The rate of carbohydrate oxidation, respiratory exchange ratio and blood lactate concentration were reduced for CHO(low) only during exercise above LT2. These results suggest that muscle glycogen depletion followed by a period of a low carbohydrate diet impairs high-intensity exercise performance.

Effect of match importance on salivary cortisol and immunoglobulin A responses in elite young volleyball players.

Abstract Moreira, A, Freitas, CG, Nakamura, FY, Drago, G, Drago, M, and Aoki, MS. Effect of match importance on salivary cortisol and immunoglobulin A responses in elite young volleyball players. J Strength Cond Res 27(1): 202–207, 2013—The purpose of this study was to compare the session ratings of perceived exertion (Session-RPE) responses and the salivary cortisol (sC) and immunoglobulin A (SIgA) levels between a regular season match (RM) and the final championship match (FM) in elite male volleyball players against the same opponent team. Higher importance was assumed for FM because this match would define the championship team. Session-RPE was obtained after 30 minutes of each match using the CR-10 scale. Saliva samples were collected before and after each match and during a rest day (baseline) at the same period of the matches. The SIgA and sC concentrations were measured by enzyme-linked immunosorbent assay. Greater Session-RPE was observed for FM as compared with RM (p < 0.01). The analysis of variance showed greater sC concentrations to FM as compared with RM for both prevalues and postvalues and compared with baseline (p < 0.05). Significant lower SIgA prevalues were noted for FM. In conclusion, the results showed that match intensity, cortisol concentration, and SIgA prelevel were affected by the match importance. These results indicate that monitoring session-RPE, sC, and SIgA responses, in conjunction, during training and competition, would provide valuable informations regarding how athletes cope with sports induced stress. This study provided knowledge about the effect of match importance on salivary markers related to stress that may help coaches to avoid excessive training loads reducing the likelihood to decrements on mucosal immunity and its consequent risk to upper respiratory tract infections, which in turn might affect the performance.

Effects of additional repeated sprint training during preseason on performance, heart rate variability, and stress symptoms in futsal players: a randomized controlled trial.

Abstract Soares-Caldeira, LF, de Souza, EA, de Freitas, VH, de Moraes, SMF, Leicht, AS, and Nakamura, FY. Effects of additional repeated sprint training during preseason on performance, heart rate variability, and stress symptoms in futsal players: A randomized controlled trial. J Strength Cond Res 28(10): 2815–2826, 2014—The aim of this study was to investigate whether supplementing regular preseason futsal training with weekly sessions of repeated sprints (RS) training would have positive effects on repeated sprint ability (RSA) and field test performance. Thirteen players from a professional futsal team (22.6 ± 6.7 years, 72.8 ± 8.7 kg, 173.2 ± 6.2 cm) were divided randomly into 2 groups (AddT: n = 6 and normal training group: n = 7). Both groups performed a RSA test, Yo-Yo intermittent recovery test level 1 (YoYo IR1), squat (SJ) and countermovement jumps (CMJ), body composition, and heart rate variability (HRV) measures at rest before and after 4 weeks of preseason training. Athletes weekly stress symptoms were recorded by psychometric responses using the Daily Analysis of Life Demands for Athletes questionnaire and subjective ratings of well-being scale, respectively. The daily training load (arbitrary units) was assessed using the session of rating perceived exertion method. After the preseason training, there were no significant changes for body composition, SJ, CMJ, and RSAbest. The YoYo IR1, RSAmean, RSAworst, and RSAdecreament were significantly improved for both groups (p ⩽ 0.05). The HRV parameters improved significantly within both groups (p ⩽ 0.05) except for high frequency (HF, absolute and normalized units, [n.u.]), low frequency (LF) (n.u.), and the LF/HF ratio. A moderate effect size for the AddT group was observed for resting heart rate and several HRV measures. Training load and psychometric responses were similar between both groups. Additional RS training resulted in slightly greater positive changes for vagal-related HRV with similar improvements in performance and training stress during the preseason training in futsal players.

Maximal lactate steady-state prediction through quadratic modeling of selected stages of the lactate minimum test.

Pardono, E, da Costa Sotero, R, Hitane, W, Mota, MR, Campbell, CSG, Nakamura, FY, and Simões, HG. Maximal lactate steady-state prediction through quadratic modeling of selected stages of the lactate minimum test. J Strength Cond Res 22: 1073-1080, 2008-In this study, we compared the maximal lactate steady state (MLSS) with lactate minimal (LM) intensities determined visually and through a quadratic polynomial function of selected stages of LM test. Eleven male recreational cyclists (27.7 ± 4.5 years, 175.7 ± 5.6 cm, 69.5 ± 10.8 kg, and 12.0 ± 5.5% body fat) performed one LM test under previous induction of hyperlactaemia with an initial intensity of 75 W with 30-W increments every 3 minutes with blood lactate concentration (HLa) and rating of perceived exertion (RPE) measurements. The LM intensity was determined visually (VLM) and by modeling the lactate response through polynomial function by using: 1) all stages (LMP); 2) the first stage, the stage corresponding to RPE-13 and the last stage/exhaustion (LMP3max); 3) the three lowest lactate concentration stages (LMP3adj); and 4) the initial, RPE-13, and RPE-16 stages (LMP3sub). The MLSS was determined as the highest intensity at a variation not greater than 0.05 mmol·l-1·min-1 of HLa during the last 20 minutes of a 30-minute exercise session. The MLSS (204.0 ± 16.0 W), VLM (198.6 ± 15.2 W), LMP3adj (190.4 ± 12.9 W), and LMP3sub (192.1 ± 27.2 W) were not different, well correlated, and in agreement to each other. In conclusion, the polynomial modeling of HLa response to three submaximal stages produced exercise intensities that did not differ from MLSS.