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1.
Front Sports Act Living ; 5: 1213924, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37822970

RESUMO

Aim: As sport and physical activity are vital to support extended health spans, this study aimed to analyse the current trends in sports participation and physical activity rates among individuals aged 65 years and older in Scotland. Data were compared with the Chief Medical Officer (CMO) guidelines and analysed the influence of key factors on participation rates. Methods: The study used data from the Scottish Health Survey and the Scottish Household Survey (2019) to investigate self-reported participation in physical activity and sports across different age groups. Descriptive statistics and cross-tabulations were used to analyse the relationships between participation rates and influencing factors. Participation data for Parkrun events in Scotland were also analysed for the years 2008-2018. Results: The study found a clear decline in sports participation with age, with a steep decline after the age of 65, particularly in women. The majority of participation among individuals aged 65+ was in walking, with a sport participation rate of only 31.2% when walking was excluded. Physical activity and sport participation was lower in women across all age ranges but particularly so in the 75+ age group. The most popular sporting activities in the older age group were keep fit/aerobics, swimming and golf. Additionally, the study found that social deprivation had a major impact on sports participation rates, with the most deprived households exhibiting the lowest participation levels irrespective of age. The prevalence of loneliness was lower among individuals who participated in sports or adhered to the CMO guidelines for moderate/vigorous physical activity and strength-building exercises. Discussion: The findings of this study have implications for promoting physical activity and sports participation among older adults, particularly in deprived communities. This study highlights the importance of balance exercises within sport and the need for more targeted efforts to increase participation rates among older adults. The study also emphasizes the positive impact of sports participation on reducing loneliness among older adults. Overall, the findings suggest the need for ongoing efforts to promote physical activity and sports participation among older adults to improve their overall health and well-being.

2.
Eur J Appl Physiol ; 117(1): 1-6, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27830328

RESUMO

PURPOSE: The Clara cell protein CC16, secreted from Clara cells in the lung, is discussed as a potential biomarker for toxic effects on the airways. An increased concentration of CC16 in serum may be caused by increased permeability of the lungs. To investigate the changes in P-CC16 in response to an intense exercise bout performed at different times of day (9 am and 4 pm) of highly trained individuals. METHOD: Using a crossover randomized design, 8 runners (mean VO2max 71 ml kg-1 min-1, SD 6) performed a 10-km time trial run, at 9 am and 4 pm, in an environmental chamber set at 6 °C. Lung function tests and blood sampling occurred at baseline, immediately post and 1 h post time trial. RESULT: Diurnal differences (P < 0.05) were found for blood neutrophil and lymphocyte counts; with higher values at 4 pm. P-CC16 was higher at the pre- and post-trial time point at 9 am compared to 4 pm. Lung function was not different between or within trials. CONCLUSION: Morning trial in cold condition caused more physiological strain compared to the same trial in the evening. However, this extra stress caused by zeitgebers could be a useful strategy for athletes, coaches, and general population to improve their running performance and protect their health in cold conditions in the long-term plan.


Assuntos
Resposta ao Choque Frio , Corrida/fisiologia , Uteroglobina/sangue , Adulto , Atletas , Biomarcadores/sangue , Humanos , Pulmão/citologia , Pulmão/imunologia , Masculino , Fotoperíodo , Distribuição Aleatória
4.
J Strength Cond Res ; 21(4): 1315-9, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18076228

RESUMO

Sprint tests are frequently used to evaluate between-subject differences and can provide a valuable insight into performance capacity. The present study determined the reproducibility of peak and mean power output during upper-body sprints. After familiarization 25 men (mean [+/- SD] age 29 [6] years, body mass 82.8 [12.7] kg and height 1.76 [0.05] m) completed 2 20-second upper-body sprint tests using an adapted cycle ergometer. Mean (+/- SD) values of all power (uncorrected and corrected) measurements achieved during the 2 tests were checked for systematic bias using separate paired t-tests. Test-retest reproducibility was examined using coefficients of variation and single-measure intraclass correlation coefficients, as well as an assessment of the typical (random) error and the 95% limits of agreement. The value of corrected peak power (628 [167] W) was higher (p < 0.05) compared with the uncorrected value (509 [109] W). Values of corrected (465 [95] W) and uncorrected (444 [87] W) mean power were similar (p > 0.05). The mean bias value for all power parameters equated to less than +/-1% of the absolute values of power measured. Intraclass correlation coefficients for all data sets ranged from 0.97 to 0.98. Coefficients of variation for uncorrected and corrected values of peak power were 2.8 and 4.5%, while corresponding values for mean power were 2.9 and 3.2%, respectively. The reproducibility of all power indices was below 5%. The results of this study indicate that both uncorrected and corrected measurements of peak power output and mean power output can be used to assess performance during sprint arm ergometry.


Assuntos
Teste de Esforço/métodos , Força Muscular/fisiologia , Adulto , Humanos , Masculino , Reprodutibilidade dos Testes , Análise e Desempenho de Tarefas
5.
Int J Sports Med ; 28(6): 525-30, 2007 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-17497583

RESUMO

The study aim was to consider the use of a motorised treadmill as a cycling ergometry system by assessing predicted and recorded power output values during treadmill cycling. Fourteen male cyclists completed repeated cycling trials on a motorised treadmill whilst riding their own bicycle fitted with a mobile ergometer. The speed, gradient and loading via an external pulley system were recorded during 20-s constant speed trials and used to estimate power output with an assumption about the contribution of rolling resistance. These values were then compared with mobile ergometer measurements. To assess the reliability of measured power output values, four repeated trials were conducted on each cyclist. During level cycling, the recorded power output was 257.2 +/- 99.3 W compared to the predicted power output of 258.2 +/- 99.9 W (p > 0.05). For graded cycling, there was no significant difference between measured and predicted power output, 268.8 +/- 109.8 W vs. 270.1 +/- 111.7 W, p > 0.05, SEE 1.2 %. The coefficient of variation for mobile ergometer power output measurements during repeated trials ranged from 1.5 % (95 % CI 1.2 - 2.0 %) to 1.8 % (95 % CI 1.5 - 2.4 %). These results indicate that treadmill cycling can be used as an ergometry system to assess power output in cyclists with acceptable accuracy.


Assuntos
Ergometria , Teste de Esforço/métodos , Esforço Físico/fisiologia , Adulto , Fenômenos Biomecânicos , Humanos , Masculino , Reino Unido
6.
Eur J Appl Physiol ; 97(4): 424-31, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16685550

RESUMO

The purpose of this article was to establish whether previously reported oxygen-to-mass ratios, used to predict flat and hill-climbing cycling performance, extend to similar power-to-mass ratios incorporating other, often quick and convenient measures of power output recorded in the laboratory [maximum aerobic power (W(MAP)), power output at ventilatory threshold (W(VT)) and average power output (W(AVG)) maintained during a 1 h performance test]. A proportional allometric model was used to predict the optimal power-to-mass ratios associated with cycling speeds during flat and hill-climbing cycling. The optimal models predicting flat time-trial cycling speeds were found to be (W(MAP)m(-0.48))(0.54), (W(VT)m(-0.48))(0.46) and (W(AVG)m(-0.34))(0.58) that explained 69.3, 59.1 and 96.3% of the variance in cycling speeds, respectively. Cross-validation results suggest that, in conjunction with body mass, W(MAP) can provide an accurate and independent prediction of time-trial cycling, explaining 94.6% of the variance in cycling speeds with the standard deviation about the regression line, s=0.686 km h(-1). Based on these models, there is evidence to support that previously reported VO2-to-mass ratios associated with flat cycling speed extend to other laboratory-recorded measures of power output (i.e. Wm(-0.32)). However, the power-function exponents (0.54, 0.46 and 0.58) would appear to conflict with the assumption that the cyclists' speeds should be proportional to the cube root (0.33) of power demand/expended, a finding that could be explained by other confounding variables such as bicycle geometry, tractional resistance and/or the presence of a tailwind. The models predicting 6 and 12% hill-climbing cycling speeds were found to be proportional to (W(MAP)m(-0.91))(0.66), revealing a mass exponent, 0.91, that also supports previous research.


Assuntos
Ciclismo , Músculo Esquelético/fisiologia , Resistência Física/fisiologia , Esforço Físico/fisiologia , Adulto , Índice de Massa Corporal , Humanos , Masculino , Modelos Biológicos , Contração Muscular , Músculo Esquelético/metabolismo , Oxigênio/metabolismo , Consumo de Oxigênio , Troca Gasosa Pulmonar , Fatores de Tempo
7.
Int J Sports Med ; 26 Suppl 1: S19-27, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15702452

RESUMO

This article summarizes the scientific literature on portable devices used for the measurement of gas exchange during exercise. Firstly, the results from validity investigations are reviewed in terms of accuracy, reliability, and influence of additional weight during field testing. On the basis of these findings, at least two of the most often tested portable devices, MetaMax I/II and K2/K4 b (2), can be regarded as valid, with their results not differing substantially from (stationary) metabolic carts. The second part of the article provides an overview of ambulatory gas exchange applications which have been investigated so far. There is a number of descriptive (cross-sectional) studies that characterize the physiological profiles of different sports. In addition, some diagnostic tests of functional capacity have been validated, and a few investigations have assessed nutritional interventions and their effect on metabolism. Some indicate potential future directions including an evaluation of the efficacy of modifying metabolic pathways during exercise, e. g. by specifically designed training. Also, the extension of descriptive/cross-sectional investigations to typical training sessions will be worthwhile.


Assuntos
Teste de Esforço/instrumentação , Monitorização Ambulatorial/instrumentação , Troca Gasosa Pulmonar , Teste de Esforço/métodos , Humanos , Monitorização Ambulatorial/métodos , Troca Gasosa Pulmonar/fisiologia , Reprodutibilidade dos Testes , Esportes/fisiologia
8.
Int J Sports Med ; 26 Suppl 1: S2-10, 2005 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-15702453

RESUMO

It is important that sources of variation in gas analysis measurements are identified and described in an accurate and informative manner. In this paper, we discussed the potential sources of error, which should be considered in any measurement study on gas analysis systems. We then covered how errors in various terms associated with gas laws propagate to outcome measurements of gas exchange to help quantify the relative importance of sources of error. Finally, we performed a literature survey to explore the statistical methods researchers have employed to arrive at conclusions on the performance characteristics of gas analysis methods. We found examples of excellent practice in the literature, but there were also gaps in the knowledge of error in gas analysis systems. Consequently, we supplied guidelines for future method comparison studies. These guidelines included (i) a sample size of at least 40 participants and the citation of confidence intervals, (ii) a description of the relationships between systematic and random errors and the size of measured value, (iii) the parallel examination of test-retest error within a method comparison study, and (iv) an a priori-made judgement on how much systematic and random error between methods is acceptable for practical applications. We stressed that this judgement should be based on expert-agreed position statements about acceptable error, which unfortunately have yet to be formulated for gas analysis systems.


Assuntos
Testes Respiratórios/instrumentação , Teste de Esforço/instrumentação , Calibragem/normas , Humanos , Análise dos Mínimos Quadrados , Troca Gasosa Pulmonar , Análise de Regressão , Reprodutibilidade dos Testes , Projetos de Pesquisa , Testes de Função Respiratória/instrumentação , Fatores de Tempo
9.
J Aging Phys Act ; 13(1): 75-86, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15677837

RESUMO

This study assessed age-related changes in power and heart rate in 114 competitive male cyclists age 15-73 years. Participants completed a maximal Kingcycle ergometer test with maximal ramped minute power (RMPmax, W) recorded as the highest average power during any 60 s and maximal heart rate (HRmax, beats/min) as the highest value during the test. From age 15 to 29 (n = 38) RMPmax increased by 7.2 W/year (r = .53, SE 49 W, p < .05). From age 30 to 73 (n = 78) RMPmax declined by 2.4 W/year (r = - .49, SE 49 W, p < .05). Heart rate decreased across the full age range by 0.66 beats . min( -1 ) . year( -1 ) (r = -.75, SE 9 beats/min, p < .05). Age accounted for only 25% of the variance in RMPmax but 56% in HRmax. RMPmax was shown to peak at age 30, then decline with age, whereas HRmax declined across the full age range.


Assuntos
Fatores Etários , Ciclismo/fisiologia , Frequência Cardíaca/fisiologia , Esforço Físico/fisiologia , Adolescente , Adulto , Idoso , Estudos Transversais , Teste de Esforço , Humanos , Masculino , Pessoa de Meia-Idade , Resistência Física/fisiologia , Aptidão Física/fisiologia
10.
Int J Sports Med ; 25(7): 479-85, 2004 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-15459827

RESUMO

The aim of this study was to determine the effects of Rotor, a new cycle crank configuration that effectively allows the pedals to move independently throughout the duty cycle, on indices of endurance cycling performance in trained cyclists. Ten cyclists (5 Rotor users and 5 non-users; age (mean +/- SD): 22 +/- 5 y; VO(2)max: 69.5 +/- 5.1 mL. kg(-1).min(-1)) volunteered to participate in the study. On four separate days, the subjects performed four cycle-ergometer tests, i.e. two incremental tests and two 20-min tests. An imposed crank rate of 75 rev.min(-1) was used during all tests. The incremental protocol started at 112.5 W, and the power output was increased by 37.5 W every 3 min until volitional exhaustion. The 20-min tests were performed at a fixed power output equivalent to 80 % of the highest power output that the cyclists maintained for a complete 3-min period during incremental tests. Both types of tests were performed with the conventional crank system and the Rotor following a counter-balanced, cross-over design. Gas exchange parameters were measured in all the tests and blood lactate was determined at the end of each 3-min period (incremental tests) and at the end of the 20-min tests. A three factor (pedalling system used during the tests x habitual pedalling system x power output [incremental tests] or time [20-min tests]) ANOVA with repeated measures on power output (incremental tests) or time (20-min tests) was used to analyse several indices of performance, e.g. peak power output, VO(2)max, lactate threshold, onset of blood lactate accumulation, economy, delta, and gross efficiency. No differences (p > 0.05) were found between the Rotor and conventional systems for any of the aforementioned variables. It seems that the theoretical advantage brought about by the Rotor system, i.e. improved contra-lateral cooperation of both legs, would be minimized in trained cyclists. Although field studies are needed to assess the possible implications, in terms of actual racing, of the new system, commonly used indicators of endurance cycling performance do not seem to be improved with the Rotor in trained cyclists.


Assuntos
Ciclismo/fisiologia , Adulto , Metabolismo Energético , Engenharia , Desenho de Equipamento , Humanos , Ácido Láctico/sangue , Masculino , Consumo de Oxigênio
11.
J Sports Sci ; 22(7): 661-7, 2004 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15370497

RESUMO

In this study, we assessed the agreement between the powers recorded during a 30 s upper-body Wingate test using three different methods. Fifty-six men completed a single test on a Monark 814E mechanically braked ergometer fitted with a Schoberer Rad Messtechnik (SRM) powermeter. A commercial software package (Wingate test kit version 2.21, Cranlea, UK) was used to calculate conventional and corrected (with accelerative forces) values of power based on a resistive load (5% body mass) and flywheel velocity. The SRM calculated powers based on torque (measured at the crank arm) and crank rate. Values for peak 1 and 5 s power and mean 30 s power were measured. No significant differences (P >0.05) were found between the three methods for 30 s power values. However, the corrected values for peak 1 and 5 s power were 36 and 23% higher (P <0.05) respectively than those for the conventional method, and 27 and 16% higher (P <0.05) respectively than those for the SRM method. The conventional and SRM values for peak 1 and 5 s power were similar (P >0.05). Power values recorded using each method were influenced by sample time (P <0.05). Our results suggest that these three measures of power are similar when sampled over 30 s, but discrepancies occur when the sample time is reduced to either 1 or 5 s.


Assuntos
Metabolismo Energético , Ergometria , Consumo de Oxigênio/fisiologia , Esforço Físico/fisiologia , Aptidão Física/fisiologia , Limiar Anaeróbio , Fenômenos Biomecânicos , Teste de Esforço , Humanos , Masculino , Software , Torque
12.
Int J Sports Med ; 24(5): 366-71, 2003 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-12868049

RESUMO

Most fitness assessments either use a constant load to exhaustion (exercise capacity test) or an "all-out" effort (performance test). The purpose of this study was to determine the reliability of a high-intensity assessment that combined a constant load element with a performance test. Ten moderately trained male cyclists completed a ramp test to voluntary exhaustion in order to measure maximum minute power output (mean +/- s, 349.3 w +/- 55.0 w). On two other occasions subjects cycled at a constant load at maximum minute power output for 2-min immediately followed by a 1-min performance test. All tests were conducted on the subjects' own bicycles using a Kingcycle trade mark test rig. Power output was measured each second using SRM trade mark Power Cranks. The data were analysed by measuring the reliability of each 30 s of the 3-min test together with the peak power and the peak cadence achieved in the performance element of the test. There was no systematic bias in the data from trial 1 to trial 2 for any of the 6, 30 s blocks of the test, the peak power (mean, 95 % CI, 413.8 w, 357.8 - 469.7 w and 403.8 w, 339.9 - 467.6 w, trial 1 and trial 2, respectively) or peak cadence (95.0 rev x min(-1), 89.5 - 100.5 rev x min(-1) and 95.1 rev x min(-1), 90.0 - 100.1 rev x min(-1), trial 1 and trial 2, respectively). Mean (+/- s) total distance over the 3-min was 2.23 +/- 0.23 km and 2.26 +/- 0.26 km for trial 1 and trial 2 respectively (p > 0.05). The coefficients of variation ranged from 0.9 - 5.4 % and the intraclass correlation coefficients ranged from 0.96 - 0.99. It is concluded that in moderately trained subjects, the 3-min combination test provides reliable data and could therefore be used for short-term, high-intensity cycling intervention studies.


Assuntos
Ciclismo/fisiologia , Ergometria/instrumentação , Teste de Esforço/instrumentação , Teste de Esforço/normas , Análise de Variância , Fenômenos Biomecânicos , Humanos , Reprodutibilidade dos Testes
13.
Br J Sports Med ; 37(3): 254-7, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12782552

RESUMO

OBJECTIVES: To compare the heart rate responses of women orienteers of different standards and to assess any relation between heart rate responses and age. METHODS: Eighteen competitive women orienteers completed the study. They were divided into two groups: eight national standard orienteers (ages 23-67 years); 10 club standard orienteers (ages 24-67 years). Each participant had her heart rate monitored during a race recognised by the British Orienteering Federation. Peak heart rate (HR(PEAK)), mean heart rate (HR(MEAN)), standard deviation of her heart rate during each orienteering race (HR(SD)), and mean change in heart rate at each control point (DeltaHR(CONTROL)) were identified. The data were analysed using analysis of covariance with age as a covariate. RESULTS: National standard orienteers displayed a lower within orienteering race standard deviation in heart rate (6 (2) v 12 (2) beats/min, p<0.001) and a lower DeltaHR(CONTROL) (5 (1) v 17 (4) beats/min, p<0.001). The mean heart rate during competition was higher in the national standard group (170 (11) v 158 (11) beats/min, p = 0.025). The HR(MEAN) for the national and club standard groups were 99 (8)% and 88 (9)% of their age predicted maximum heart rate (220-age) respectively. All orienteers aged >55 years (n = 4) recorded HR(MEAN) greater than their age predicted maximum. CONCLUSIONS: The heart rate responses indicate that national and club standard women orienteers of all ages participate in the sport at a vigorous intensity. The higher DeltaHR(CONTROL) of club standard orienteers is probably due to failing to plan ahead before arriving at the controls and this, coupled with slowing down to navigate or relocate when lost, produced a higher HR(SD).


Assuntos
Frequência Cardíaca/fisiologia , Orientação/fisiologia , Corrida/fisiologia , Adulto , Distribuição por Idade , Fatores Etários , Idoso , Análise de Variância , Comportamento Competitivo/fisiologia , Feminino , Humanos , Pessoa de Meia-Idade , Análise de Regressão
14.
J Sports Sci ; 21(3): 221-8, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12703851

RESUMO

Orienteering is a sport in which it is common for most participants to be aged over 40 years, but research into the demands of the sport has focused almost exclusively on elite participants aged 21-35 years. The aim of the present study was to examine the heart rate responses of older male orienteers. Thirty-nine competitive male orienteers were divided into three groups: group 1 (international competitive standard, n = 11, age 21-67 years), group 2 (national competitive standard, n = 15, age 24-66 years) and group 3 (club competitive standard, n = 13, age 23-60 years). Each participant had his heart rate monitored during two orienteering races of contrasting technical difficulty. The results were analysed using analysis of covariance, with age as a covariate, and Pearson product-moment correlation coefficients to determine whether age was related to the observed heart rate responses. The groups did not differ in their peak (175 +/- 12 beats x min(-1), P = 0.643) or mean (159 +/- 13 beats x min(-1), P = 0.171) heart rates during the races. There was a decline of 6 beats x min(-1) x decade(-1) (P = 0.001) for peak heart rate and 5 beats x min(-1) x decade(-1) (P < 0.001) for mean heart rate. Mean heart rates were 86 +/- 6% of the participants' maximal heart rates and were not associated with age. The orienteers in group 1 displayed a lower (P < 0.005) within-race standard deviation in heart rate (6 +/- 2 beats x min(-1)) than those in groups 2 and 3 (10 +/- 3 and 10 +/- 4 beats x min(-1), respectively). In conclusion, the mean heart rates indicated that all three groups of orienteers ran at a relative high intensity and the international competitive standard orienteers displayed a less variable heart rate, which may have been related to fewer instances of slowing down to relocate and being able to navigate while running at relatively high speeds.


Assuntos
Frequência Cardíaca , Resistência Física/fisiologia , Corrida/fisiologia , Adulto , Comportamento Competitivo/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade
15.
Med Sci Sports Exerc ; 34(11): 1744-9, 2002 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-12439078

RESUMO

PURPOSE: The aim of the study was to examine the effects of different lactate elevation protocols on the determination of the lactate minimum (Lac(min)) point. METHODS: Eight highly trained racing cyclists each completed four continuous ramp lactate minimum tests using the following blood lactate elevation protocols: 1) continuous ramp maximal aerobic power (RMP(max)) assessment, 2) 30-s maximal sprint, 3) 40-s maximal sprint, and 4) two 20-s maximal sprints separated by a 1-min recovery. Each blood lactate elevation protocol was followed by a 5-min active recovery leading into a continuous ramp test commencing at a power of 60% of RMP(max), using a 6 W x min ramp rate, lasting 15 min. RESULTS: Peak [La](b) values were significantly higher (P > 0.05) after the RMP(max) compared with all other protocols and higher in the 40-s versus 30-s sprint. However, by the start of Lac(min) ramp, [La](b) after the RMP(max) was no longer higher than the 40-s sprint, but Lac(min) [La](b) was similar for all protocols. This resulted in no differences in the total decline of [La](b) measured as a percentage from the highest to the lowest value. At Lac(min) point, there were no significant differences in power (P > 0.05), but heart rate was higher in the RMP versus 2 x 20 s and VO(2) was significantly higher after the 40 s compared with the 2 x 20 s protocol. CONCLUSION: This study demonstrated that the determination of lactate minimum power in cycling is not dependent upon the lactate elevation protocol.


Assuntos
Ciclismo/fisiologia , Metabolismo Energético/fisiologia , Lactatos/sangue , Esforço Físico/fisiologia , Adulto , Limiar Anaeróbio , Análise de Variância , Estudos de Coortes , Intervalos de Confiança , Teste de Esforço , Feminino , Humanos , Lactatos/metabolismo , Ácido Láctico/sangue , Ácido Láctico/metabolismo , Masculino , Consumo de Oxigênio/fisiologia , Resistência Física/fisiologia , Probabilidade
16.
Med Sci Sports Exerc ; 34(11): 1785-92, 2002 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-12439084

RESUMO

PURPOSE: The purpose of this investigation was to assess the acute effects of caffeine ingestion on short-term, high-intensity exercise (ST) after a period of oral creatine supplementation and caffeine abstinence. METHODS: Fourteen trained male subjects performed treadmill running to volitional exhaustion (T(lim)) at an exercise intensity equivalent to 125% VO(2max). Three trials were performed, one before 6 d of creatine loading (0.3 g x kg x d(-1) baseline), and two further trials after the loading period. One hour before the postloading trials, caffeine (5 mg x kg(-1)) or placebo was orally ingested in a cross-over, double-blind fashion. Four measurements of rating of perceived exertion were taken, one every 30 s, during the first 120 s of the exercise. Blood samples were assayed for lactate, glucose, potassium, and catecholamines, immediately before and after exercise. RESULTS: Body mass increased (P < 0.05) over the creatine supplementation period, and this increase was maintained for both caffeine and placebo trials. There was no increase in the maximal accumulated oxygen deficit between trials; however, total VO(2) was significantly increased in the caffeine trial in comparison with the placebo trial (13.35 +/- 3.89 L vs 11.67 +/- 3.61 L). In addition, caffeine T(lim) (222.1 +/- 48.9 s) was significantly greater (P < 0.05) than both baseline (200.8 +/- 33.4 s) and placebo (198.3 +/- 45.4 s) T(lim). RPE was also lower at 90 s in the caffeine treatment (13.8 +/- 1.8 RPE points) in comparison with baseline (14.6 +/- 1.9 RPE points). CONCLUSION: As indicated by a greater T(lim), acute caffeine ingestion was found to be ergogenic after 6-d of creatine supplementation and caffeine abstinence.


Assuntos
Cafeína/administração & dosagem , Creatina/administração & dosagem , Suplementos Nutricionais , Metabolismo Energético/fisiologia , Teste de Esforço , Esforço Físico/efeitos dos fármacos , Corrida/fisiologia , Adulto , Limiar Anaeróbio/efeitos dos fármacos , Limiar Anaeróbio/fisiologia , Análise de Variância , Análise Química do Sangue , Gasometria , Estimulantes do Sistema Nervoso Central/administração & dosagem , Método Duplo-Cego , Humanos , Masculino , Fadiga Muscular/fisiologia , Resistência Física/efeitos dos fármacos , Esforço Físico/fisiologia , Probabilidade , Valores de Referência , Sensibilidade e Especificidade
17.
Int J Sports Med ; 22(4): 270-4, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11414669

RESUMO

The purpose of this study was to assess reliability of both indoor and outdoor 40 km time-trial cycling performance. Eight trained cyclists completed three indoor 40 km time-trials on an air-braked ergometer (Kingcycle) and three outdoor 40 km time-trials on a local course. Power output was measured for all trials using the SRM powermeter. Mean performance time across three indoor trials was 54.21 +/- 2.59 (min:sec) and was significantly different (P<0.05) to mean time across three outdoor trials (57.29 +/- 3.22 min:sec). However, there was no significant difference (P = 0.34) for mean power across three indoor trials (303+/-35W) when compared to outdoor performances (312 +/- 23 W). Within-subject variation for mean power output expressed as a coefficient of variation (CV) improved in both indoors and outdoors for trials 2 and 3 (CV = 1.9%, 95% CI 1.0 - 3.4 and CV = 2.1 %, 95 % CI 1.1 - 3.8) when compared to trials 1 and 2 (CV=2.1%, 95% CI 1.2-3.8 and CV=2.4%, 95% CI 1.3-4.3). These findings indicate that power output measured using the SRM powermeter is highly reproducible for both laboratory-based and actual 40 km time-trial cycling performance.


Assuntos
Ciclismo/fisiologia , Adulto , Análise de Variância , Fenômenos Biomecânicos , Percepção de Distância , Meio Ambiente , Ergometria , Humanos , Masculino , Reprodutibilidade dos Testes
18.
J Sports Sci ; 19(4): 243-52, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11311022

RESUMO

The aim of this study was to assess the effects of the age and sex of the competitor on orienteering speed during competitive events. The results of the fastest three male and fastest three female competitors in each 5-year age band (21-79 years), from four national orienteering events, were analysed. The data for age and orienteering speed were log-transformed and regression analyses were conducted to determine the relationships between age and sex and orienteering speed. For comparison, data for the fastest Great Britain finisher in the 10,000-m track and 10-km cross-country events for age groups 40-69 years at the World Masters Championships were also analysed. The results showed that, before the age of 40 years, there was no substantial slowing in orienteering speed for males (0.5-4.2% per decade) but a moderate decline (4.7-10.0% per decade) for females. After the age of 45 years, the orienteering speed of males and females slowed by 13+/-2% and 16+/-4% per decade (mean +/- s), respectively, until around the age of 69, after which the deterioration was accentuated. The orienteering speed of the females was 81+/-4, 74+/-6 and 69+/-7% that of the males at ages 21, 45 and 65 years, respectively. The magnitudes of the age-related slowing of orienteering speed and of the difference in orienteering speed between males and females aged 45 years and over were greater than those reported for the other endurance running events. This may reflect the physical demands of running in orienteering terrain, tactical and cognitive aspects of the sport, or sociocultural aspects of the participating population.


Assuntos
Envelhecimento/fisiologia , Corrida/fisiologia , Esportes/fisiologia , Adulto , Fatores Etários , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resistência Física/fisiologia , Análise de Regressão , Fatores Sexuais
19.
Med Sci Sports Exerc ; 32(10): 1790-3, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11039654

RESUMO

PURPOSE: To assess the reliability of the Kingcycle ergometer, this study compared peak power recorded using a Kingcycle and SRMTM power meters during Kingcycle maximal aerobic power tests. METHODS: The study was completed in two parts: for part 1, nine subjects completed three maximal tests with a stabilizing kit attached to the Kingcycle rig and calibration of the Kingcycle checked against SRM (MAP(C)); and for part 2, nine subjects completed two maximal tests without the stabilizing kit and the Kingcycle calibrated using the standard procedure (MAP(S)). Each MAP(C) test was separated by 1 wk; however, MAPs tests were separated by 54 +/- 32 d, (mean +/- SD). Testing procedure was repeated for each MAP and peak power output was calculated as the highest average power output recorded during any 60-s period of the MAP test using the Kingcycle (King(PPO)) and SRM (SRM(PPO)). RESULTS: Coefficient of variations (CVs) for King(PPO) were larger than those of SRM(PPO); 2.0% (95%CI = 1.5-3.0) versus 1.3% (95%CI = 1.0-2.0) and 4.6% (95%CI = 2.7-7.6) versus 3.6% (95%CI = 2.1-6.0) for MAPC( and MAP(S), respectively. During all tests, King(PPO) was higher than SRM(PPO) by an average of approximately 10% (P < 0.001). CONCLUSIONS: Investigators should be aware of the discrepancy between the two systems when assessing peak power and that SRM cranks provide a more reproducible measure of peak power than the Kingcycle ergometer.


Assuntos
Ciclismo , Teste de Esforço/instrumentação , Teste de Esforço/normas , Desenho de Equipamento , Humanos , Reprodutibilidade dos Testes
20.
Br J Sports Med ; 34(4): 289-92, 2000 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10953903

RESUMO

OBJECTIVES: (a) To determine if factor XIIa (FXIIa) would be sensitive to change from exercise intervention in a group of previously sedentary/low active middle aged men and women; (b) to investigate further the previously reported relation between FXIIa and triacylglycerol (TAG) rich lipoproteins. METHODS: Thirty seven men (mean (SD) age 57 (7) years) and 60 women (mean age 54 (7) years) completed the study. Before the intervention, these subjects were randomly allocated to a group of walkers (n = 81) or controls (n = 16). Before and after an 18 week walking intervention, fasted blood samples were collected and analysed for FXIIa, TAG, total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), and apolipoprotein (apo) B. RESULTS: Kruskal-Wallis analysis of data obtained before the intervention showed no significant differences (p>0.4) between the walking and control groups for age, height, body mass, gender, FXIIa, TAG, TC, HDL-C, or apo B, although the women did show significantly lower levels of TAG (p<0.04) and higher HDL-C (p<0.0001) than the men. General linear model analysis of data obtained after the intervention, using the baseline value as a covariate, showed significant reductions (p<0.0001) in FXIIa for the walkers compared with the controls. Pearson product-moment correlations also showed significant relations between the concentrations of FXIIa and TAG, TC, LDL-C, and apo B. CONCLUSIONS: The findings of this study suggest that FXIIa is sensitive to change from exercise intervention and support previous research showing an association between the concentrations of FXIIa and TAG rich lipoproteins.


Assuntos
Exercício Físico/fisiologia , Fator XIIa/análise , Lipoproteínas/análise , Caminhada/fisiologia , HDL-Colesterol/análise , LDL-Colesterol/análise , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Triglicerídeos/análise
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