The ramp and all-out exercise test to determine critical power: validity and robustness to manipulations in body position.

Purpose: The purpose of the present study was to determine whether a contiguous ramp and all-out exercise test could accurately determine critical power (CP) in a single laboratory visit during both upright and supine cycle exercise.

Methods: Healthy males completed maximal ramp-incremental exercise on a cycle ergometer in the upright (n = 15) and supine positions (n = 8), with task failure immediately followed by a 3-min all-out phase for determination of end-test power (EP). On separate days, participants undertook four constant-power tests in either the upright or supine positions with the limit of tolerance ranging from ~ 2 to 15 min for determination of CP.

Clustered cardiometabolic risk and arterial stiffness of recreational adult tennis players.

Background: Recent evidence highlights racquet sports as being associated with a substantially reduced risk of CVD mortality. The purpose of this investigation was to evaluate clustered cardiometabolic risk (CMR) and arterial stiffness in recreational adult tennis players.

Methods: Forty-three recreational tennis players (T) and a matched group of 45 healthy, active non-tennis (NT) players, mean age (±SEM) 41.

Limitations to exercise tolerance in type 1 diabetes: the role of pulmonary oxygen uptake kinetics and priming exercise.

We compared the time constant () of the fundamental phase of pulmonary oxygen uptake (V̇o) kinetics between young adult men with type 1 diabetes and healthy control subjects. We also assessed the impact of priming exercise on , critical power, and muscle deoxygenation in a subset of participants with type 1 diabetes. Seventeen men with type 1 diabetes and 17 healthy male control subjects performed moderate-intensity exercise to determine .

Effect of Hyperoxia on Critical Power and V˙O2 Kinetics during Upright Cycling.

Introduction/purpose: Critical power (CP) is a fundamental parameter defining high-intensity exercise tolerance; however, its physiological determinants are incompletely understood. The present study determined the impact of hyperoxia on CP, the time constant of phase II pulmonary oxygen uptake kinetics (τV˙O2), and muscle oxygenation (assessed by near-infrared spectroscopy) in nine healthy men performing upright cycle ergometry.

Methods: Critical power was determined in normoxia and hyperoxia (fraction of inspired O2 = 0.

The Musculoskeletal Health Benefits of Tennis.

Background: The prevalence of musculoskeletal (MSK) conditions is increasing, and although current guidelines for physical activity attempt to combat this, many fail to achieve the recommended targets. The present study sought to investigate whether regular tennis participation is more effective at enhancing MSK function than meeting the current international physical activity guidelines.

Hypothesis: Tennis players will display significantly enhanced MSK function when compared with age-matched healthy active nonplayers.

Hyperoxia speeds pulmonary oxygen uptake kinetics and increases critical power during supine cycling.

New Findings: What is the central question of this study? Critical power is a fundamental parameter defining high-intensity exercise tolerance and is related to the phase II time constant of pulmonary oxygen uptake kinetics ( ). To test whether this relationship is causal, we assessed the impact of hyperoxia on and critical power during supine cycle exercise. What is the main finding and its importance? The results demonstrate that hyperoxia increased muscle oxygenation, reduced (i.

"Work-to-Work" exercise slows pulmonary oxygen uptake kinetics, decreases critical power, and increases W' during supine cycling.

We have previously demonstrated that the phase II time constant of pulmonary oxygen uptake kinetics ( ) is an independent determinant of critical power (CP) when O availability is not limiting, that is, during upright cycle exercise in young, healthy individuals. Whether this causative relationship remains when O availability is impaired remains unknown. During supine exercise, which causes an O availability limitation during the exercise transition, we therefore determined the impact of a raised baseline work rate on and CP.

Evaluating the progressive cardiovascular health benefits of short-term high-intensity interval training.

Purpose: High-intensity training is recognised as a time-efficient way of improving aerobic fitness. However, there is a lack of consensus regarding the temporal nature of adaptation response and which peripheral and cardiac changes occur using the same exercise stimulus and protocol. Therefore, this study aimed to evaluate the progression of vascular and cardiac changes over a 6-week training period.

Elevated baseline work rate slows pulmonary oxygen uptake kinetics and decreases critical power during upright cycle exercise.

Critical power is a fundamental parameter defining high-intensity exercise tolerance, and is related to the phase II time constant of pulmonary oxygen uptake kinetics (τV˙O2). Whether this relationship is causative is presently unclear. This study determined the impact of raised baseline work rate, which increases τV˙O2, on critical power during upright cycle exercise.

Prior exercise speeds pulmonary oxygen uptake kinetics and increases critical power during supine but not upright cycling.

What is the central question of this study? Critical power (CP) represents the highest work rate for which a metabolic steady state is attainable. The physiological determinants of CP are unclear, but research suggests that CP might be related to the time constant of phase II oxygen uptake kinetics (τV̇O2). What is the main finding and its importance? We provide the first evidence that τV̇O2 is mechanistically related to CP.

Changing incidence of bovine babesiosis in Ireland.

Background: In Ireland bovine babesiosis is caused by the tick-borne blood parasite, Babesia divergens. A survey of veterinary practitioners and farmers in the 1980's revealed an annual incidence of 1.7% associated with considerable economic losses.

Oxygen uptake kinetics in trained adolescent females.

Unlabelled: Little evidence exists with regard to the effect that exercise training has upon oxygen uptake kinetics in adolescent females.

Purpose: The aim of the study was to compare [Formula: see text] and muscle deoxygenation kinetics in a group of trained (Tr) and untrained (Utr) female adolescents.

Method: Twelve trained (6.

Cardiac strain during upright cycle ergometry in adolescent males.

Little evidence exists with regard to changes in cardiac strain that occur during submaximal exercise in young males. The aims of the study were to evaluate the changes that occur in longitudinal (L), radial (R), and endocardial circumferential (EC) strain during submaximal upright cycle ergometry and to examine the test-retest reproducibility of these measurements. Fourteen recreationally active, adolescent (age: 17.

Orthostatic effects on echocardiographic measures of ventricular function.

Orthostatic-induced alterations in Doppler echocardiographic measures of ventricular function have not been well-defined. Identifying such changes may provide useful insights regarding the responses of these measures to variations in ventricular loading conditions. Standard assessment of mitral inflow velocity and tissue Doppler imaging (TDI) of left ventricular longitudinal myocardial velocities was performed on 14 young males (mean age 17.

Time-of-day effect on cardiac responses to progressive exercise.

This study was designed to examine time-of-day effects on markers of cardiac functional capacity during a standard progressive cycle exercise test. Fourteen healthy, untrained young males (mean ± SD: 17.9 ± 0.

Pulmonary oxygen uptake and muscle deoxygenation kinetics during recovery in trained and untrained male adolescents.

Previous studies have demonstrated faster pulmonary oxygen uptake (VO2) kinetics in the trained state during the transition to and from moderate-intensity exercise in adults. Whilst a similar effect of training status has previously been observed during the on-transition in adolescents, whether this is also observed during recovery from exercise is presently unknown. The aim of the present study was therefore to examine VO2 kinetics in trained and untrained male adolescents during recovery from moderate-intensity exercise.

Myocardial function and aerobic fitness in adolescent females.

A recent report indicated that variations in myocardial functional (systolic and diastolic) responses to exercise do not contribute to inter-individual differences in aerobic fitness (peak VO(2)) among young males. This study was designed to investigate the same question among adolescent females. Thirteen highly fit adolescent football (soccer) players (peak VO(2) 43.

Sex influence on myocardial function with exercise in adolescents.

Objectives: Ventricular systolic functional response to exercise has been reported to be superior in adult men compared to women. This study explored myocardial responses to maximal upright progressive exercise in late pubertal males and females.

Methods: Doppler echocardiographic techniques were utilized to estimate myocardial function response to a bout of progressive cycle exercise.

Levels and patterns of physical activity in children and adolescents with type 1 diabetes and associated metabolic and physiologic health outcomes.

Background: The current study objectively assessed physical activity (PA) levels and patterns in children and adolescents with type 1 diabetes and compared the metabolic and physiologic health profiles of those achieving and those not achieving the current recommendation of 60 minutes a day (minutes x D(-1)) of at least moderate intensity PA.

Method: 37 children and adolescents (20 boys, 17 girls) aged 12.7 +/- 2.

Skin microvascular reactivity in trained adolescents.

Whilst endothelial dysfunction is associated with a sedentary lifestyle, enhanced endothelial function has been documented in the skin of trained individuals. The purpose of this study was to investigate whether highly trained adolescent males possess enhanced skin microvascular endothelial function compared to their untrained peers. Seventeen highly and predominantly soccer trained boys (V(O)(2)(peak): 55 +/- 6 mL kg(-1) min(-1)) and nine age- and maturation-matched untrained controls (V(O)(2)(peak): 43 +/- 5 mL kg(-1) min(-1)) aged 13-15 years had skin microvascular endothelial function assessed using laser Doppler flowmetry.

Faster pulmonary oxygen uptake kinetics in trained versus untrained male adolescents.

Unlabelled: Exercise training results in a speeding of pulmonary oxygen uptake (VO2) kinetics at the onset of exercise in adults; however, only limited research has been conducted with children and adolescents.

Purpose: The aim of the present study was to examine VO2 and muscle deoxygenation kinetics in trained and untrained male adolescents.

Methods: Sixteen trained (15 +/- 0.

Myocardial performance during progressive exercise in athletic adolescent males.

Purpose: The extent that enhanced ventricular function contributes to superior aerobic fitness of trained athletes is unclear. This study compared cardiovascular responses to progressive cycle exercise in 12 adolescent soccer players and 10 untrained boys with assessment of ventricular inotropic and relaxation properties by Doppler ultrasound techniques.

Methods: Resting cardiac dimensions were measured by M-mode echocardiography.