Critical Load Forced-swim Test With Wistar Rats Does Not Properly Estimate Anaerobic Threshold: The Relationship With Morphophysiological Factors And Performance Indices

Objective: The study aimed to correlate morphophysiological characteristics associated with performance and indices associated with the critical power model, and to verify the time to exhaustion (Tlim) at critical load (CL) intensityMethods: Twenty male Wistar rats were submitted to four predictive tests to determine CL and anaerobic swim capacity (ASC) intensity using hyperbolic and Busso's modelsSubsequently, they were submitted to exercise at 100% of CL intensity derived from hyperbolic model until exhaustion, and the time was recorded to the nearest secondThe day after, animals were euthanized for blood and tissue collectionResults: Significant relationships were found among the indices CL, ASC (derived from the both models) and Tlim (P0.05)Conclusion: We can conclude that the CL rat swimming model does not properly estimate the anaerobic threshold intensityFurthermore, the correlations with morphophysiological variables indicate that none of variables alone can account for performance at CL intensity© 2013.283e51e57Scherrer, J., Samson, M., Paléologue, A., Étude du travail musculaire et de la fatigueDonnées ergométriques obtenues chez l'homme (1954) J Physiol, 46, pp. 887-916Moritani, T., Nagata, A., deVires, H.A., Muor, M., Critical power as a measure of physical work capacity and anaerobic threshold (1981) Ergonomics, 24, pp. 339-350Hughson, R.L., Orok, C.J., Staudt, L.E., A high velocity treadmill test to assess endurance running potential (1984) Int J Sports Med, 5, pp. 23-25Wakayoshi, K., Ikuta, K., Yoshida, T., Udo, M., Moritani, T., Mutoh, Y., Determination and validity of critical velocity as an index of swimming performance in the competitive swimmers (1992) Eur J Appl Physiol, 64, pp. 153-157Gaesser, G.A., Wilson, L.A., Effects of continuous and interval training on the parameters of the power endurance time relationship for high-intensity exercise (1988) Int J Sports Med, 9, pp. 417-421Poole, D.C., Ward, S.A., Gardner, G.W., Whipp, B.J., Metabolic and respiratory profile of the upper limit for prolonged exercise in man (1988) Ergonomics, 31, pp. 1265-1279Miura, A., Sato, H., Sato, H., Whipp, B.J., Fukuba, Y., The effect of glycogen depletion on the curvature constant parameter of the power-duration curve for cycle ergometry (2000) Ergonomics, 43, pp. 133-141Gaesser, A.G., Carnevale, T.J., Garfinkel, A., Walter, D.O., Womack, C.J., Estimation of critical power with nonlinear and linear models (1995) Med Sci Sports Exerc, 27, pp. 1430-1438Bishop, D., Jenkins, D.G., Howard, A., The critical power function is dependent on the duration of the predictive exercise tests chosen (1998) Int J Sports Med, 19, pp. 125-129Housh, T.J., Johnson, G.O., McDowell, S.L., Housh, D.J., Pepper, M., Physiological responses at the fatigue threshold (1991) Int J Sports Med, 12, pp. 305-308Brickley, G., Doust, J., Williams, C.A., Physiological responses during exercise to exhaustion at critical power (2002) Eur J Appl Physiol, 88, pp. 146-151Baron, B., Dekerle, J., Robin, S., Neviere, L., Dupont, L., Matran, R., Physiological responses during exercise performed to exhaustion at critical power (2005) J Hum Mov Stud, 49, pp. 169-180Busso, T., Chantagnon, M., Modelling of aerobic and anaerobic energy production in middle-distance running (2006) Eur J Appl Physiol, 97, pp. 745-754Busso, T., Chantagnon, M., An extended model of power-exhaustion time to estimate aerobic and anaerobic energy production during intense exercise (2008) Sci and Sports, 23, pp. 239-243Miura, A., Endo, M., Sato, H., Sato, H., Barstow, T.J., Fukuba, Y., Relationship between the curvature constant parameter of the power-duration curve and muscle cross-sectional area of the thigh for cycle ergometry in humans (2002) Eur J Appl Physiol, 87, pp. 238-244Marangon, L., Gobatto, C.A., Mello, M.A.R., Kokubun, E., Utilization of an hyperbolic model for the determination of critical load in swimming rats (2002) Med Sci Sports Exer, 34 (SUPPL1), pp. 149-159Hill, D.W., The critical power concept (1993) Sports Med, 16, pp. 237-254Bancroft, J.D., Hand, N.M., (1987) Enzyme histochemistry, , Oxford University Press, LondonPearse, A.G.E., (1972) Histochemistry: theoretical and applied, , Williams & Wilkins, BaltimoreArmstrong, R.B., Phelps, R.O., Muscle fiber composition of the rat hindlimb (1984) Am J Anat, 171, pp. 259-272Srere, P.A., Brazil, H., Gonen, L., The citrate condensing enzyme of pigeon breast muscle and moth flight muscle (1963) Acta Chem Scand, 17, pp. 129-134McLellan, T.M., Cheung, K.S.Y., A comparative evaluation of the individual anaerobic threshold and the critical power (1992) Med Sci Sports Exerc, 24, pp. 543-550Jenkins, D.G., Quigley, B.M., Blood lactate in trained cyclists during cycle ergometry at critical power (1990) Eur J Appl Physiol, 61, pp. 278-283Gobatto, C.A., Manchado, F.B., Voltarelli, F.A., Contarteze, R.V.L., Mello, M.A.R., Non-invasive critical load determination in swimming rats: effects of muscle glycogen depletion (2005) Med Sci Sports Exerc, 37 (SUPPL1), pp. 331-341Poole, D.C., Ward, S.A., Whipp, B.J., The effect of training on the metabolic and respiratory profile of high-intensity cycle ergometer exercise (1990) Eur J Appl Physiol, 59, pp. 421-429Vanhatalo, A., Fulford, J., DiMenna, F., Jones, A.M., Influence of hyperoxia on muscle metabolic responses and the power-duration relationship during severe-intensity exercise in humans: a 31P-MRS study (2010) Exp Physiol, 95, pp. 528-540Dekerle, J., Carter, H., Effect of moderate hypoxia on the power-endurance relationship (2009) Med Sci Sports Exerc, 41 (SUPPL1), pp. 256-266Sjödin, B., Jacobs, I., Onset of blood lactate accumulation and marathon running performance (1981) Int J Sports Med, 2, pp. 23-26Howlett, R.A., Gonzalez, N.C., Wagner, H.E., Fu, Z., Britton, S.L., Koch, L.G., Skeletal muscle capillarity and enzyme activity in rats selectively bred for running endurance (2003) J Appl Physiol, 94, pp. 1682-1688Green, H.J., Jones, S., Ball-Burnett, M.E., Smith, D., Livesev, J., Farrane, B.W., Early muscular and metabolic adaptations to prolonged exercise training in humans (1991) J Appl Physiol, 70, pp. 2032-2038Tonkonogi, M., Harris, B., Sahlin, K., Increased activity of citrate synthase in human skeletal muscle after a single bout of prolonged exercise (1997) Acta Physiol Scand, 161, pp. 435-436Kariya, F., Yamauchi, H., Kobayashi, K., Narusawa, M., Nakahara, Y., Effects of prolonged voluntary wheel-running on muscle structure and function in rat skeletal muscle (2004) Eur J Appl Physiol, 92, pp. 90-97Abbiss, C.R., Laursen, P.B., Model to explain fatigue during prolonged endurance cycling (2005) Sports Med, 35, pp. 865-898Rivero, J.L.L., Serrano, A.L., Henckel, P., Agüera, E., Muscle fiber type composition and fiber size in successfully and unsuccessfully endurance-raced horses (1993) J Appl Physiol, 75, pp. 1758-1766Totsuka, Y., Nagao, Y., Horii, T., Yonekawa, H., Imai, H., Hatta, H., Physical performance and soleus muscle fiber composition in wild-derived and laboratory inbred mouse strains (2003) J Appl Physiol, 95, pp. 720-727Barnard, R.J., Edgerton, V.R., Furukawa, T., Peter, J.B., Histochemical, biochemical and contractile properties of red, white and intermediate fibers (1971) Am J Physiol, 220, pp. 410-414Conley, K.E., Kayar, S.R., Roesler, K., Hoppeler, H., Weibel, E.R., Taylor, C.R., Adaptive variation in the mammalian respiratory system in relation to energetic demand: IV capillaries and their relationship to oxidative capacity (1987) Respir Physiol, 69, pp. 166-170Kayar, S.R., Hoppeler, H., Jones, J.H., Longworth, K., Armstrong, R., Laughlin, M.H., Capillary blood transit time in muscles in relation to body size and aerobic capacity (1994) J Exp Biol, 194, pp. 69-81Schumacher, Y.O., Schmid, A., Grathwohl, D., Bültermann, D., Berg, A., Hematological indices and iron status in athletes of various sports and performances (2002) Med Sci Sports Exerc, 34, pp. 869-87

Hypofractionated radiotherapy in the real-world setting : an international ESTRO- GIRO survey

Background and purpose: Multiple large trials have established the non-inferiority of hypofractionated radiotherapy compared to conventional fractionation. This study will determine real-world hypofractionation adoption across different geographic regions for breast, prostate, cervical cancer, and bone metastases, and identify barriers and facilitators to its use. Materials and methods: An anonymous, electronic survey was distributed from January 2018 through January 2019 to radiation oncologists through the ESTRO-GIRO initiative. Predictors of hypofractionation were identified in univariable and multivariable regression analyses. Results: 2316 radiation oncologists responded. Hypofractionation was preferred in node-negative breast cancer following lumpectomy (82·2% vs. 46·7% for node-positive; p < 0.001), and in low- and intermediate-risk prostate cancer (57·5% and 54·5%, respectively, versus 41·2% for high-risk (p < 0.001)). Hypofractionation was used in 32·3% of cervix cases in Africa, but <10% in other regions (p < 0.001). For palliative indications, hypofractionation was preferred by the majority of respondents. Lack of long-term data and concerns about local control and toxicity were the most commonly cited barriers. In adjusted analyses, hypofractionation was least common for curative indications amongst low- and lower-middle-income countries, Asia-Pacific, female respondents, small catchment areas, and in centres without access to intensity modulated radiotherapy. Conclusion: Significant variation was observed in hypofractionation across curative indications and between regions, with greater concordance in palliation. Using inadequate fractionation schedules may impede the delivery of affordable and accessible radiotherapy. Greater regionally-targeted and disease-specific education on evidence-based fractionation schedules is needed to improve utilization, along with best-case examples addressing practice barriers and supporting policy reform

Determination Of The Maximum Accumulated Oxygen Deficit: Effects Of The Submaximal Tests Duration For Prediction Of Oxygen Demand [determinação Do Máximo Déficit Acumulado De Oxigênio: Efeito Da Duração Dos Testes Submáximos Para Predição Da Demanda De Oxigênio]

The aim of this study was to investigate the influence of different assessment time periods of submaximal tests on the determination of the maximal accumulated oxygen deficit (MAOD), through the adoption of different time slots of 4 to 6, 6 to 8 and 8 to 10 min. Ten cyclists with mean age of 27.5 ± 4.1 years, body mass 74.4 ± 12.7 kg and time experience of 9.8 ± 4.7 years participated in this study. The athletes underwent an incremental exercise test to determine the peak oxygen consumption (VO2peak), and four submaximal constant work-load test sessions (60, 70, 80 and 90% VO2peak) of 10 min in order to estimate the O2 demand (DEO2). The mean VO2 values obtained on each constant work-load for the 4 to 6, 6 to 8 and 8 to 10 min time-periods intervals were used to perform a linear regression between the intensity and O2 consumption for each time-period. In addition, the subjects performed one supramaximal rectangular test (110% VO2peak) for the quantification of MAOD. There was no significant difference in VO2 between the different time-periods for all submaximal tests (P&gt; 0.05). Similarly, no significant difference was found in DEAO2 and MAOD (P&gt; 0.05). Furthermore, the values of MAOD for the three time-periods intervals showed good agreement and strong correlation. Thus, the data suggest that the submaximal tests used to estimate the values of MAOD can be reduced, at least in this type of sample, and with the use of a cycle simulator.166445449Medbo, J.I., Mohn, A.C., Tabata, I., Bahr, R., Vaage, O., Sejersted, O.M., Anaerobic capacity determined by maximal accumulated O2 deficit (1988) J Appl Physiol., 64, pp. 50-60Bertuzzi, R.C.M., Silva, A.E.L., Pires, F.O., Kiss, M.A.P.D.M., Déficit acumulado de oxigênio: Uma breve revisão histórica e metodológica (2008) Revista de Educação Física/UEM, 19, pp. 131-144Nakamura, F.Y., Franchini, E., Máximo déficit acumulado de oxigênio como preditor de capacidade anaeróbia (2006) Revista Brasileira de Cineantropometria & Desempenho Humano, 8, pp. 88-95Calbet, J.A., Chavarren, J., Dorado, C., Fractional use of anaerobic capacity during a 30-and a 45-s Wingate test (1997) Eur J Appl Physiol Occup Physiol., 76, pp. 308-313Levine, B.D., Stray-Gundersen, J., "Living high-training low": Effect of moderate-altitude acclimatization with low-altitude training on performance (1997) J Appl Physiol., 83, pp. 102-112Weber, C.L., Schneider, D.A., Increases in maximal accumulated oxygen deficit after high-intensity interval training are not gender dependent (2002) J Appl Physiol., 92, pp. 1795-1801Bell, D.G., Jacobs, I., Ellerington, K., Effect of caffeine and ephedrine ingestion on anaerobic exercise performance (2001) Med Sci Sports Exerc., 33, pp. 1399-1403Doherty, M., The effects of caffeine on the maximal accumulated oxygen deficit and short-term running performance (1998) Int J Sport Nutr., 8, pp. 95-104Doherty, M., Smith, P.M., Schroder, K., Reproducibility of the maximum accumulated oxygen deficit and run time to exhaustion during short-distance running (2000) J Sports Sci., 18, pp. 331-338Hargreaves, M., Finn, J.P., Withers, R.T., Halbert, J.A., Scroop, G.C., McKay, M., Effect of muscle glycogen availability on maximal exercise performance (1997) Eur J Appl Physiol Occup Physiol., 75, pp. 188-192Sloniger, M.A., Cureton, K.J., O'Bannon, P.J., One-mile run-walk performance in young men and women: Role of anaerobic metabolism (1997) Can J Appl Physiol., 22, pp. 337-350Wadley, G., le Rossignol, P., The relationship between repeated sprint ability and the aerobic and anaerobic energy systems (1998) J Sci Med Sport., 1, pp. 100-110Woolford, S.M., Withers, R.T., Craig, N.P., Bourdon, P.C., Stanef, T., McKenzie, I., Effect of pedal cadence on the accumulated oxygen deficit, maximal aerobic power and blood lactate transition thresholds of highperformance junior endurance cyclists (1999) Eur J Appl Physiol Occup Physiol., 80, pp. 285-291Gardner, A., Osborne, M., D'Auria, S., Jenkins, D., A comparison of two methods for the calculation of accumulated oxygen deficit (2003) J Sports Sci., 21, pp. 155-162Buck, D., McNaughton, L., Maximal accumulated oxygen deficit must be calculated using 10-min time periods (1999) Med Sci Sports Exerc., 31, pp. 1346-1349Gordon, C.C., Chumlea, W.C., Roche, A.F., Stature, recumbent length, and weight (1988) Anthropometric standardization reference manual, pp. 3-8. , In: Lohman TG, Roche AF, Martorell R, editors, Champaign: Human Kinetics BooksHirai, D.M., Okuno, N.M., Perandini, L.A.B., Puga, G.M., Simões, H.G., Nakamura, F.Y., Cinética do consumo de oxigênio durante exercícios supramáximos: Aplicação de modelos matemáticos (2008) Revista Brasileira de Cineantropometria & Desempenho Humano, 10, pp. 43-49Barstow, T.J., Jones, A.M., Nguyen, P.H., Casaburi, R., Influence of muscle fiber type and pedal frequency on oxygen uptake kinetics of heavy exercise (1996) J Appl Physiol., 81, pp. 1642-1650Casaburi, R., Storer, T.W., Ben-Dov, I., Wasserman, K., Effect of endurance training on possible determinants of VO2 during heavy exercise (1987) J Appl Physiol., 62, pp. 199-207Billat, V., Binsse, V., Petit, B., Koralsztein, J.P., High level runners are able to maintain a VO2 steady-state below VO2max in an all-out run over their critical velocity (1998) Arch Physiol Biochem., 106, pp. 38-4

Comparison Between Anaerobic Threshold Determined By Ventilatory Variables And Blood Lactate Response In Cyclists [comparação Entre Limiar Anaeróbio Determinado Por Variáveis Ventilatórias E Pela Resposta Do Lactato Sanguíneo Em Ciclistas]

Many investigations have shown that the coincidence between the ventilatory thresholds and those thresholds using the lactate response does not happen all of the time, suggesting that there is no relationship between the cause-effect between these phenomena. Thus, the present study had as main purpose to compare and correlate the Oxygen consumption (V̇O2), the power (W), and the heart rate (HR) values attained using protocols to determine the Ventilatory Threshold (VT) and the Individual Anaerobic Threshold (IAT). The sampling was constituted by eight State and National level cyclists (age: 27.88 ± 8.77 years; body mass: 65.19 ± 4.40 kg; height: 169.31 ± 5,77 cm). The IAT was determined starting from a three minutes 50 W warm up with progressive increases of 50 W.3min-1 up to achieving the voluntary exhaustion, when the blood was collected in the last 20 seconds of each phase, and during the recovering period. In order to determine the VT, it was used the same protocol used to determine the IAT, but without performing the blood collection. The VT was identified through the changes in the pulmonary ventilation, as well as of the ventilatory equivalent of the O2 and CO2. The t-Student test showed no significant statistical difference in any of the attained variables. The associations found were high and significant. The V̇O2 (ml.kg-1.min.-1), P (W), and HR (bpm) corresponding to the VT and IAT, as well as the associations between variables were respectively: 48.00 ± 3.82 vs. 48.08 ± 3.71 (r = 0.90); 256.25 ± 32.04 vs. 246.88 ± 33.91 (r = 0.84); 173.75 ± 9.18 vs. 171.25 ± 12.02 (r = 0.97). According to the results attained, it can be concluded that the IAT and the VT produce similar V̇O2, W, and HR values, favoring the adoption of the VT because it is a non-invasive method to determine the anaerobic threshold in cyclists.12134e38eJacobs, I., Blood lactate. Implications for training and sports performance (1986) Sports Med, 3, pp. 10-25Kindermann, W., Simon, G., Keul, J., The significance of the aerobic-anaerobic transition for the determination of work load intensities during endurance training (1979) Eur J Appl Physiol Occup Physiol, 42, pp. 25-34Meyer, T., Gabriel, H.H., Kindermann, W., Is determination of exercise intensities as percentages of V̇O2max or HRmax adequate? (1999) Med Sci Sports Exerc, 31, pp. 1342-1345Keith, S.P., Jacobs, I., McLellan, T.M., Adaptations to training at the individual anaerobic threshold (1992) Eur J Appl Physiol Occup Physiol, 65, pp. 316-323Gaskill, S.E., Walker, A.J., Serfass, R.A., Bouchard, C., Gagnon, J., Rao, D.C., Changes in ventilatory threshold with exercise training in a sedentary population: The Heritage Family Study (2001) Int J Sports Med, 22, pp. 586-592Coyle, E.F., Integration of the physiological factors determining endurance performance ability (1995) Exerc Sport Sci Rev, 23, pp. 25-63Coyle, E.F., Feltner, M.E., Kautz, S.A., Hamilton, M.T., Montain, S.J., Baylor, A.M., Physiological and biomechanical factors associated with elite endurance cycling performance (1991) Med Sci Sports Exerc, 23, pp. 93-107Roecker, K., Schotte, O., Niess, A.M., Horstmann, T., Dickhuth, H.H., Predicting competition performance in long-distance running by means of a treadmill test (1998) Med Sci Sports Exerc, 30, pp. 1552-1557Wasserman, K., McIlroy, M.B., Detecting the threshold of anaerobic metabolism in cardiac patients during exercise (1964) Am J Cardiol, 14, pp. 844-852Heck, H., Mader, A., Hess, G., Mucke, S., Muller, R., Hollmann, W., Justification of the 4-mmol/l lactate threshold (1985) Int J Sports Med, 6, pp. 117-130McLellan, T.M., Ventilatory and plasma lactate response with different exercise protocols: A comparison of methods (1985) Int J Sports Med, 6, pp. 30-35Mader, A., Liesen, H., Heck, H., Philippi, H., Schürch, P.M., Hollmann, W., Zur beurteilung der sportartspezifischen Ausdauerleinstungsfähigkeit im Labor (1976) Sportarzt Sportmed, 26, pp. 109-112Mader, A., Liesen, H., Heck, H., Philippi, H., Schürch, P.M., Hollmann, W., Zur beurteilung der sportartspezifischen Ausdauerleinstungsfähigkeit im Labor (1976) Sportarzt Sportmed, 24, pp. 80-88Sjodin, B., Jacobs, I., Onset of blood lactate accumulation and marathon running performance (1981) Int J Sports Med, 2, pp. 23-26Hollmann, W., Historical remarks on the development of the aerobic-anaerobic threshold up to 1966 (1985) Int J Sports Med, 6, pp. 109-116Stegmann, H., Kindermann, W., Schnabel, A., Lactate kinetics and individual anaerobic threshold (1981) Int J Sports Med, 2, pp. 160-165Coen, B., Schwarz, L., Urhausen, A., Kindermann, W., Control of training in middle-and long-distance running by means of the individual anaerobic threshold (1991) Int J Sports Med, 12, pp. 519-524McLellan, T.M., Cheung, K.S., Jacobs, I., Incremental test protocol, recovery mode and the individual anaerobic threshold (1991) Int J Sports Med, 12, pp. 190-195McLellan, T.M., Cheung, K.S., A comparative evaluation of the individual anaerobic threshold and the critical power (1992) Med Sci Sports Exerc, 24, pp. 543-550Urhausen, A., Coen, B., Weiler, B., Kindermann, W., Individual anaerobic threshold and maximum lactate steady state (1993) Int J Sports Med, 14, pp. 134-139Urhausen, A., Weiler, B., Coen, B., Kindermann, W., Plasma catecholamines during endurance exercise of different intensities as related to the individual anaerobic threshold (1994) Eur J Appl Physiol Occup Physiol, 69, pp. 16-20Beneke, R., Anaerobic threshold, individual anaerobic threshold, and maximal lactate steady state in rowing (1995) Med Sci Sports Exerc, 27, pp. 863-867Bourgois, J., Vrijens, J., Metabolic and cardiorespiratory responses in young oarsmen during prolonged exercise tests on a rowing ergometer at power outputs corresponding to two concepts of anaerobic threshold (1998) Eur J Appl Physiol Occup Physiol, 77, pp. 164-169Baldari, C., Guidetti, L., A simple method for individual anaerobic threshold as predictor of max lactate steady state (2000) Med Sci Sports Exerc, 32, pp. 1798-1802Guidetti, L., Musulin, A., Baldari, C., Physiological factors in middleweight boxing performance (2002) J Sports Med Phys Fitness, 42, pp. 309-314Stegmann, H., Kindermann, W., Comparison of prolonged exercise tests at the individual anaerobic threshold and the fixed anaerobic threshold of 4 mmol.l(-1) lactate (1982) Int J Sports Med, 3, pp. 105-110Bourgois, J., Vrijens, J., The Conconi test: A controversial concept for the determination of the anaerobic threshold in young rowers (1998) Int J Sports Med, 19, pp. 553-559Dickhuth, H.H., Yin, L., Niess, A., Rocker, K., Mayer, F., Heitkamp, H.C., Ventilatory, lactate-derived and catecholamine thresholds during incremental treadmill running: Relationship and reproducibility (1999) Int J Sports Med, 20, pp. 122-127McNaughton, L., Wakefield, G., Fasset, R., Bentley, D., A comparison of lactate kinetics, minute ventilation and acid-base balance as measure of the anaerobic threshold (2001) Journal of Human Moviment Studies, 41, pp. 247-261Hughes, E.F., Turner, S.C., Brooks, G.A., Effects of glycogen depletion and pedaling speed on anaerobic threshold" (1982) J Appl Physiol, 52, pp. 1598-1607Yoshida, T., Effect of dietary modifications on lactate threshold and onset of blood lactate accumulation during incremental exercise (1984) Eur J Appl Physiol Occup Physiol, 53, pp. 200-205Berry, M.J., Stoneman, J.V., Weyrich, A.S., Burney, B., Dissociation of the ventilatory and lactate thresholds following caffeine ingestion (1991) Med Sci Sports Exerc, 23, pp. 463-469McLellan, T.M., Jacobs, I., Active recovery, endurance training, and the calculation of the individual anaerobic threshold (1989) Med Sci Sports Exerc, 21, pp. 586-592Aunola, S., Rusko, H., Does anaerobic threshold correlate with maximal lactate steady-state? (1992) J Sports Sci, 10, pp. 309-323Ribeiro, J.P., Hughes, V., Fielding, R.A., Holden, W., Evans, W., Knuttgen, H.G., Metabolic and ventilatory responses to steady state exercise relative to lactate thresholds (1986) Eur J Appl Physiol Occup Physiol, 55, pp. 215-221Yamamoto, Y., Miyashita, M., Hughson, R.L., Tamura, S., Shinohara, M., Mutoh, Y., The ventilatory threshold gives maximal lactate steady state (1991) Eur J Appl Physiol Occup Physiol, 63, pp. 55-59Wyatt, F.B., Comparison of lactate and ventilatory threshold to maximal oxygen consumption: A meta analysis (1999) Journal of Strength and Conditioning Research, 13, pp. 67-71Ahmaidi, S., Hardy, J.M., Varray, A., Collomp, K., Mercier, J., Prefaut, C., Respiratory gas exchange indices used to detect the blood lactate accumulation threshold during an incremental exercise test in young athletes (1993) Eur J Appl Physiol Occup Physiol, 66, pp. 31-36Dickstein, K., Barvik, S., Aarsland, T., Snapinn, S., Karlsson, J., A comparison of methodologies in detection of the anaerobic threshold (1990) Circulation, 81, pp. II38-II46Davis, J.A., Frank, M.H., Whipp, B.J., Wasserman, K., Anaerobic threshold alterations caused by endurance training in middle-aged men (1979) J Appl Physiol, 46, pp. 1039-1046Beaver, W.L., Wasserman, K., Whipp, B.J., A new method for detecting anaerobic threshold by gas exchange (1986) J Appl Physiol, 60, pp. 2020-2027Simon, J., Young, J.L., Blood, D.K., Segal, K.R., Case, R.B., Gutin, B., Plasma lactate and ventilation thresholds in trained and untrained cyclists (1986) J Appl Physiol, 60, pp. 777-781Davis, J.A., Anaerobic threshold: Review of the concept and directions for future research (1985) Med Sci Sports Exerc, 17, pp. 6-21Stone, M.H., Sands, W.A., Stone, M.E., The downfall of sports science in the United States (2004) Strength Cond J, 26, pp. 72-7

Behavior Of The Muscle Strength And Arm Muscle Area During 24 Weeks Of Weight Training [comportamento Da Força Muscular E Da área Muscular Do Braço Durante 24 Semanas De Treinamento Com Pesos]

The purpose of this study was to analyze the behavior of muscle strength and arm muscle area (AMA) over 24 weeks of weight training (WT) as well as to establish possible associations between these variables. The sample was composed of 18 men aged between 18 and 30 years. Measurements of relaxed arm circumference and triceps skinfold measurement were used for the calculation. Muscle strength was assessed using the one-repetition maximum test (1-RM) on the arm curl exercise. The WT protocol lasted 24 weeks, divided into 3 stages (F1, F2, and F3) of 8 weeks each. It is important to emphasize that every measurement was made before, during and after the end of the WT period. Analysis of variance (ANOVA) for repeated measures followed by the Tukey post hoc (P < 0.05) was used to the compare the indicators of muscle strength and muscle hypertrophy. Pearson's correlation coefficient was used to verify possible association between muscle strength and AMA. Muscle strength and AMA increased continuously throughout the whole period except for the initial period (F1). Therefore, it is concluded that the initial phase of training, neuromuscular adaptation, seems to have been the turning point for increase in muscle strength. After that, the hypertrophy process appears to gradually become the essential factor for increase in muscle strength.104379385Position Stand: Progression models in resistance training for healthy adults (2002) Med Sci Sports Exerc, 34 (2), pp. 364-380. , American College of Sports MedicineBernhardt, D.T., Gomez, J., Johnson, M.D., Martin, T.J., Rowland, T.W., Small, E., Strength training by children and adolescents (2001) Pediatrics., 107 (6), pp. 1470-1472Kraemer, W.J., Ratamess, N.A., Fundamental of resistance training: Progression and exercise prescription (2004) Med Sci Sports Exerc, 36 (1), pp. 674-688Jones, D.A., Rutherford, O.M., Parker, D.F., Physiological changes in skeletal muscle as a result of strength training (1989) Q J Exp Physiol, 74 (3), pp. 233-256Moritani, T., Time course of adaptations during strength and power training (1992) The encyclopedia of sports medicine: Strength and power in sport., pp. 266-278. , In: Komi PV, editor. London: Blackwell ScientificSale, T., Neural adaptation to strength training (1992) The encyclopedia of sports medicine: Strength and power in sport., pp. 249-265. , In: Komi PV. London: Blackwell ScientificGoldspink, G., Cellular and molecular aspects of adaptation in skeletal muscle (1992) The encyclopedia of sports medicine: Strength and power in sport., pp. 211-229. , In: Komi PV, editor. London: Blackwell ScientificMcDougall, J.D., Hypertrophy or hyperplasia (1992) The encyclopedia of sports medicine: Strength and power in sport., pp. 230-238. , In: Komi PV, editor. London: Blackwell ScientificMoritani, T., DeVries, H.A., Neural factors versus hypertrophy in the time course of muscle strength gain (1979) Am J Phys Med, 58 (3), pp. 115-130Ploutz, L.L., Tesch, P.A., Biro, R.L., Dudley, G.A., Effect of resistance training on muscle use during exercise (1994) J Appl Physiol, 76 (4), pp. 1675-1681Staron, R.S., Karapondo, D.L., Kraemer, W.J., Fry, A.C., Gordon, S.E., Falkel, J.E., Skeletal muscle adaptation during early phase of heavy-resistance training in men and women (1994) J Appl Physiol, 76 (3), pp. 1247-1255McGinley, C., Jensen, R.L., Byrne, C.A., Shafat, A., Earlyphase strength gains during traditional resistance training compared with an upper-body air-resistance training device (2007) J Strength Cond Res, 21 (2), pp. 621-627Newton, R.U., Häkkinen, K., Häkkinen, A., McCormick, M., Volek, J., Kraemer, W.J., Mixed-methods resistance training increases power and strength of young and older men (2002) Med Sci Sports Exerc, 34 (8), pp. 1367-1375Rodrigues, C.E.C., Rocha, P.E.C.P., (1985) Musculação: Teoria e prática., , Rio de Janeiro: SprintClarke, D.H., Adaptations in strength and muscular endurance resulting from exercise (1973) Exercise and Sports Sciences Reviews., pp. 73-102. , In: Wilmore JH, editor. New York: Academic PressGordon, C.C., Chumlea, W.C., Roche, A.F., Stature, recumbent length, weight (1988) Anthropometric standardizing reference manual., pp. 3-8. , In: Lohman TG, Roche AF, Martorell R., editors. Champaign, Illinois: Human Kinetics BooksCallaway, C.W., Chumlea, W.C., Bouchard, C., Himes, J.H., Lohman, T.G., Circumferences (1988) Anthropometric standardizing reference manual., pp. 39-54. , In: Lohman TG, Roche AF, Martorell R., editors. Champaign, Illinois: Human Kinetics BooksHarrison, G.G., Buskirk, E.R., Lindsay Carter, J.E., Johnston, F.E., Lohman, T.G., Pollock, M.L., Skinfold thicknesses and measurements technique (1988) Anthropometric standardizing reference manual., pp. 55-80. , In: Lohman TG, Roche AF, Martorell R., editors. Champaign, Illinois: Human Kinetics BooksFrisancho, A.R., New standards of weight and body composition by frame size and height for assessment of nutritional status of adults and the elderly (1984) Am J Clin Nutr, 40 (4), pp. 808-819Dias, R.M.R., Cyrino, E.S., Salvador, E.P., Nakamura, F.Y., Pina, F.L.C., Oliveira, A.R., Impacto de oito semanas de treinamento com pesos sobre a força muscular de homens e mulheres (2005) Rev Bras Med Espor te, 11 (4), pp. 224-228Kraemer, W.J., Deschenes, M.R., Fleck, S.J., Physiological adaptations to resistance exercise: Implications for athletic conditioning (1988) Sports Med, 6 (4), pp. 246-256McCarthy, J.P., Pozniak, M.A., Agre, J.C., Neuromuscular adaptations to concurrent strength and endurance training (2002) Med Sci Sports Exerc, 34 (3), pp. 511-519Abe, T., Kojima, K., Kearns, C.F., Yohena, H., Fukuda, J., Whole body muscle hyper trofhy from resistance training: Distribution and total mass (2003) Br J Sports Med, 37 (1), pp. 543-545Dias, R.M.R., Cyrino, E.S., Salvador, E.P., Caldeira, L.F.S., Nakamura, F.Y., Papst, R.R., Influência do processo de familiarização para a avaliação dos níveis de força muscular em testes de 1-RM (2005) Rev Bras Med Esporte, 11 (1), pp. 34-38Houston, M.E., Froese, E.A., Valeriote, S.T.P., Green, H.J., Ranney, D.A., Muscle per formance, morphology, and metabolic capacity during strength training and detraining: A one leg model (1983) Eur J Appl Physiol, 51 (1), pp. 25-35Jones, D.A., Rutherford, O.M., Human muscle strength training: The effects of three different regimes and the nature of the resultant changes (1987) J Physiol, 391 (1), pp. 1-11Ploutz, L.L., Tesch, P.A., Biro, R.L., Dudley, G.A., Effect of resistance training on muscle use during exercise (1994) J Appl Physiol, 76 (4), pp. 1675-1681Chilibeck, P.D., Calder, A.W., Sale, D.G., Webber, C.E., A comparison of strength and muscle mass increases during resistance training in young women (1998) Eur J Appl Physiol Occup Physiol, 77 (2), pp. 170-175Cureton, K.J., Collins, M.A., Hill, D.W., McElhannon, F.M., Muscle hypertrophy in men and women (1988) Med Sci Sports Exerc, 20 (4), pp. 338-344Bloomer, R.J., Ives, J.C., Varying neural and hypertrophic influences in a strength program (2000) J Strength Cond Res, 22 (2), pp. 30-3

Association Between The Electromyographic Fatigue Threshold And Ventilatory Threshold

The objective of this study is to verify the coincidence between the occurrence of the electromyographic fatigue threshold (EMGth) and the ventilatory threshold (Vth) in an incremental test in the cyclosimulator, as well as to compare the calculation of the RMS from the EMG signal using different time windows. Thirteen male cyclists (73.7 ± 12.4 kg and 174.3 ± 6.2 cm) performed a ramp incremental test (TI) in a cyclosimulator until voluntary exhaustion. Before the start of each TI subjects had the active bipolar electrodes placed over the superficial muscles of the quadriceps femoris (QF) of the right leg: rectus femoris (RF), vastus medialis (VM) and vastus lateralis (VL). The paired student's t test, pearson's correlation coefficient and the analysis method described by Bland and Altman for the determination of the concordance level were used for statistical analysis. The significance level adopted was P &lt; 0.05. Although no significant differences were found between Vth and the EMG th calculated from windows of 2, 5, 10, 30 and 60 seconds in the studied muscles, it is suggested that the EMGth values determined from the calculation of the RMS curve with windows of 5 and 10 seconds seem to be more appropriate for the calculation of the RMS curve and determination of EMGth from visual inspection.496-7305310Basmajian, J.V., DeLuca, C.J., (1985) Muscles Alive: Their Functions Revealed by Electromyography, , Williams & WilkinsBland, J.M., Altman, D.G., Statistical methods for assessing agreement between two methods of clinical measurement (1986) Lancet, 1, pp. 307-310(2006) Encyclopedia of Medical Devices and Instrumentation, pp. 98-109. , DELUCA, C.J.: Electromyography. In: WEBSTER, J.G. (Ed.). John Wiley PublisherGordon, C.C., Chumlea, W.C., Roche, A.F., Stature, recumbent length, and weight (1988) Anthropometric Standardization Reference Manual, , T. LOHMAN, G., ROCHE, A.F. and MARTORELL, F., eds. Champaign: Human KineticsHelal, J.N., Guezennec, C.Y., Goubel, F., The aerobic-anaerobic transition: Re-examination of the threshold concept including an electromyographic approach (1987) Eur. J. Appl. Physiol., 56, pp. 643-649Hermens, H.J., Freriks, B., Disselhorst-Klug, C., Rau, G., Development of recommendations for SEMG sensors and sensor placement procedures (2000) J. Electromyogr. Kinesiol., 10 (5), pp. 361-374Hug, F., Laplaud, D., Savin, B., Grelot, L., Occurrence of electromyographic and ventilatory thresholds in professional road cyclists (2003) Eur. J. Appl. Physiol., 90 (5-6), pp. 643-646Hug, F., Raucher, M., Kipson, N., Jammes, Y., EMG signs of neuromuscular fatigue related to the ventilatory threshold during cycling exercise (2003) Clin. Physiol. Funct. Imaging., 23 (4), pp. 208-214Hug, F., Faucher, M., Marqueste, T., Guillot, C.H., Kipson, N., Jammes, Y., Electromyographic signs of neuromuscular fatigue are concomitant with further increase in ventilation during static handgrip (2004) Clin. Physiol. Funct. Imaging., 24 (1), pp. 25-32Hug, F., Laplaud, D., Lucia, A., Grelot, L.A., Comparison of visual and mathematical detection of the electromyographic threshold during incremental pedaling exercise: A pilot study (2006) Journal of Strength and Conditioning Research, 20 (3), pp. 704-708Merletti, R., Knaflitz, M., DeLuca, C.J., Electrically evoked myoelectric signals (1992) Crit. Rev. Biomed. Eng., 19 (4), pp. 293-340McLellan, T.M., Ventilatory and plasma lactate response with different exercise protocols: A comparison of methods (1985) Int. J. Sports Med., 6 (1), pp. 30-35Moritani, T., (1980) Anaerobic Threshold Determination by Electromyography (Doctoral Dissertation), , University of Southerns CaliforniaNagata, A., Muro, M., Moritani, T., Yoshida, T., Anaerobic threshold determination by blood lactate and myoelectric signals (1981) Jpn. J. Physiol., 31 (4), pp. 585-597Viitasalo, J.T., Luhtanen, P., Rahkila, P., Rusko, H., Electromyographic activity related to aerobic and anaerobic threshold in ergometer bicycling (1985) Acta. Physiol. Scand., 124 (2), pp. 287-29

Neurocognitive Performance in Adults Treated With Radiation for a Primary Brain Tumor

The contributory effects of radiation dose to different brain regions on neurocognitive performance after radiation therapy (RT) for primary brain tumors is not well known. Methods and Materials In this retrospective cohort study, 30 patients with brain tumors treated with photon RT were identified, and radiation dosimetric parameters across brain regions were calculated. All patients had longitudinal neurocognitive evaluations at baseline and after treatment. Generalized estimating equations were used to model each neurocognitive endpoint over time in a multivariable analysis, while adjusted for multiple comparisons of brain regions. Results Median follow-up from RT to last assessment was 4.1 years. Fewer years of formal education and older age at the time of RT were associated with lower scores in language, verbal memory, and working memory, after adjustment for baseline scores in multivariable analyses. Higher radiation dose to specific brain regions was not associated with declines in any of the evaluated cognitive domains. On average, there was no clinically significant decline (magnitude of z score change >1) between first and last neurocognitive evaluation. Across each individual cognitive domain, fewer than 15% of patients were impaired at most recent follow-up. Conclusions In this small study of 30 patients treated with RT for a primary brain tumor, brain region dosimetry was not associated with decline in cognitive performance. Older age at time of RT and fewer years of formal education were associated with declines in cognitive performance, suggesting that effects of nondosimetric factors on cognitive performance should be considered alongside treatment factors and dosimetry in neuro-oncology research