The purpose of this study was to examine the reliability of the intermittent critical velocity (ICV) test and assess critical rest interval (CRI) during repeated-sprint exercise. The ICV test is used to examine the linear relationship between total distance and time-to-exhaustion during interval exercise, yielding a repeatable, moderate-intensity parameter (ICV), ...

Gait disorders have been identified as one of the most influential physical impairments associated with deterioration in daily living activities among the elderly. A better understanding of the mechanisms responsible for gait disorders is important for developing intervention strategies for the elderly. In recent years, positron emission tomography (PET) and ...

BACKGROUND: -End-stage heart failure is associated with impaired cardiac output (CO) and organ blood flow. We determined whether CO and peripheral perfusion are maintained during exercise in patients with an axial-flow left ventricular assist device (LVAD) and whether an increase in LVAD pump speed with work rate would increase organ ...

Prolonged strenuous exercise is associated with the appearance of biomarkers of cardiac cell damage and a decline in cardiac function during recovery. Few studies have assessed repeated bouts of prolonged exercise and whether this results in further biomarker accumulation and greater dysfunction. Further, it may be useful to describe the ...

Advanced age is associated with altered skeletal muscle hemodynamic control during the transition from rest to exercise. This study investigated the effects of aging on the functional role of nitric oxide (NO) in regulating total, inter- and intra-muscular hindlimb hemodynamic control at rest and during submaximal whole-body exercise. We hypothesized ...

Abstract Surface features such as uneven playing surfaces, low impact absorption capacity and inappropriate friction/traction characteristics are connected with injury prevalence whereas force impact during foot strike has been suggested to be an important mechanism of intravascular haemolysis during running. We aimed to evaluate intravascular haemolysis during running and compare ...

This study investigated the effect of dynamic exercise in a hot environment on muscle fibre conduction velocity (MFCV) of the knee extensors during a sustained isometric contraction. Seven trained male cyclists (mean [±SD], age, and V˙O(2max) were 35±9.9 and 57.4±6.6mlkg(-1)min(-1)) cycled for 50min at 60% of peak power output in ...

We compared relative exercise intensity and active energy expenditure (AEE) on trail walking in the mountains, with those of daily exercise training, and whether branched-chain amino acid (BCAA) and arginine supplementation attenuated the release of markers indicating muscle damage and declines in physical performance. Twenty-one subjects (~63 years) were divided into ...

Hoffman, JR, Ratamess, NA, Kang, J, Gonzalez, AM, Beller, NA, and Craig, SAS. Effect of 15 days of betaine ingestion on concentric and eccentric force outputs during isokinetic exercise. J Strength Cond Res 25(X): 000-000, 2011-The purpose of this study was to examine the efficacy of 15 days of betaine ...

We introduced a novel non-constrained technique for estimating heart rate variability (HRV) using a ballistocardiogram (BCG). To assess whether the BCG signal can be used to analyse the cardiac autonomic modulation, HRV parameters derived from the BCG signal (ballistocardiographic HRV, B-HRV) were statistically compared with the HRV parameters from the ...

The development of fatigue is more pronounced in the heat than thermoneutral environments; however, it is unclear whether biomarkers of central fatigue are consistent with the higher core temperature (T (c)) tolerated by endurance trained (TR) versus untrained (UT) during exertional heat stress (EHS). The purpose of this study was ...

BACKGROUND AND RESEARCH OBJECTIVES:: Most children with congenital heart disease (CHD) are expected to survive to adolescence and adulthood owing to medical advances and care management. These adolescents need to be well informed about their exercise capacity and take greater personal responsibility for their exercise behavior as they mature. The ...

This study was designed to clarify the effects of breathing with prolonged expiration on cardiopulmonary responses and autonomic nervous activity during incremental exercise. Eleven healthy men were randomly assigned to breathing mode: a prolonged expiration breathing with a 2-s inspired time and 4-s expired time and a spontaneous breathing without ...

Chronic thromboembolic pulmonary hypertension (CTEPH) represents an important differential diagnosis to idiopathic pulmonary arterial hypertension (IPAH). We hypothesized that the capillary to end-tidal CO2 gradient at rest and during exercise might help differentiate CTEPH from IPAH. Patients who presented with unequivocal IPAH or CTEPH according to ventilation/perfusion scan, pulmonary angiography, ...

In general, syncope in children and adolescents is a benign event. Syncope during exercise may identify patients with a potentially fatal condition. Catecholaminergic polymorphic ventricular tachycardia is characterized by life-threatening ventricular arrhythmias, usually polymorphic ventricular tachycardia or ventricular fibrillation, occurring under conditions of exercise or emotional stress. Catecholaminergic polymorphic ventricular ...

During maximal hypoxic exercise, a reduction in cerebral oxygen delivery may constitute a signal to the central nervous system to terminate exercise. We investigated whether the rate of increase in frontal cerebral cortex oxygen delivery is limited in hypoxic compared to normoxic exercise. We assessed frontal cerebral cortex blood flow ...

Abstract Experiments were conducted to determine whether low-speed swimming during recovery from exhaustive exercise improved both metabolic recovery and performance during a swimming challenge. For these experiments, brook trout were allowed to recover from exhaustive exercise for 2 h while swimming at 0, 0.5, 1.0, or 1.5 body length (BL) ...

Vernillo, G, Piacentini, MF, Drake, A, Agnello, L, Fiorella, P, and La Torre, A. Exercise intensity and pacing strategy of a 5-km indoor race walk during a world record attempt: A case study. J Strength Cond Res 25(7): 2048-2052, 2011-The aim of this case study was to describe the physiological ...

Echocardiography is a widely used evaluation tool in cardiovascular research. Although rats are a common model in such research, normal echocardiographic values for young, developing rats have not been established. Furthermore, whether exercise during the developmental phase of the lifespan affects the structure or function of the heart is unclear. ...

High intensity leg cycle ergometry is a widely used method of measuring muscular performance during maximal exercise. Until recently, it was deemed to be a predominantly lower body activity; however, there is now evidence to suggest that the upper body could be making a significant contribution to power output, as ...

Treadmill exercise testing is a commonly used diagnostic test for the assessment of chest discomfort and exercise-induced arrhythmias. The presence of ST-segment elevation during exercise is considered a marker of severe ischaemia, usually secondary to a critical lesion in a proximal coronary artery. We present a novel cause of ST-segment ...

The purpose of this study was to compare the peak and submaximal metabolic and cardiorespiratory responses during steady-state arm-powered (AP) and arm-trunk-powered (ATP) handbike ergometry. Twelve male able-bodied participants with no prior experience in handcycling completed a maximal progressive incremental test and a series of 6-minute submaximal tests at 130 ...

The impact of regular exercise on energy balance, fuel utilization, and nutrient availability, during weight regain was studied in obese rats, which had lost 17% of their weight by a calorie-restricted, low-fat diet. Weight reduced rats were maintained for 6 wk with and without regular treadmill exercise (1 h/day, 6 ...

OBJECTIVES.-: Sildenafil and, recently, bosentan have been reported to increase arterial saturation and exercise capacity at altitude. The mechanisms behind this are still poorly defined but may be related to attenuation of hypoxic pulmonary vasoconstriction (HPV) and improved gas exchange. This study was designed to examine and compare the effect ...

Aim:  Continuous glucose monitoring system (CGMS) provides detailed information on glucose fluctuations. The aim was to establish whether CGMS could be used during physical exercise, and if it detects more episodes of hypoglycaemia and hyperglycaemia than frequent blood glucose measurements. Methods:  Adolescents with type 1 diabetes (12 girls, 47 boys) ...

Little is known regarding how attention to emotional stimuli is affected during simultaneously performed exercise. Attentional biases to emotional face stimuli were assessed in 34 college students (17 women) using the dot-probe task during counterbalanced conditions of moderate- (heart rate at 45% peak oxygen consumption) and high-intensity exercise (heart rate ...

The purpose of this study was to determine whether the reduction in stroke volume (SV) previously shown to occur with dehydration and increases in internal body temperatures during prolonged exercise is caused by a reduction in left ventricular (LV) function as indicated by LV volumes, strain and twist ('LV mechanics'). ...

The purpose of this study was to examine the effect different cycling cadences have on heart rate variability (HRV) when exercising at constant power outputs. Sixteen males had ECG and respiratory measurements recorded at rest and during 8, 10 min periods of cycling at four different cadences (40, 60, 80 ...

Long-term cardiorespiratory fitness (CRF) and the development of type 2 diabetes mellitus are inversely correlated. Here, we examined the relationships between peak oxygen uptake (VO(2)peak), on the one hand, and glucose infusion rate at rest (GIR(rest)) and during exercise (GIR(exercise)), as well as insulin secretion (both the early and late ...

Multi-sensor body monitors that combine accelerometry with other physiological data are designed to overcome drawbacks of accelerometers in assessing activities with little or no vertical movement. One of such devices is the Sensewear Armband (SWA) which has been extensively validated during various activities. However, very few of the validation studies ...

Employing Self-Determination Theory (Deci & Ryan, 1985) as a theoretical framework, this study examined psychological need satisfaction and motivational regulations as predictors of psychological and behavioural outcomes in exercise referral (ER). ER patients (N = 293; mean age 54.49) completed the measures of motivational regulations, psychological need satisfaction, health-related quality of life, ...

This investigation tested the hypothesis that breathing oxygen-enriched air (F(i) O(2) =1.00) during recovery enhances peak (P(peak) ) and mean power (P(mean) ) output during repeated high-intensity exercise. Twelve elite male swimmers (21 ± 3 years, 192.1 ± 5.9 cm, 79.1 ± 8.2 kg) inhaled either hyperoxic (HOX) or normoxic (NOX) air ...

Introduction:  Several studies have shown that activation of the sympathetic nervous system results in increased secretion of α-amylase (sAA), an enzyme produced by salivary glands. Recently, chromogranin A (CgA), a soluble protein co-stored and co-released with catecholamines from the adrenal medulla and sympathetic nerve endings, has been proposed as a ...

Resting arterial H(+) concentration ([H(+)]a) is in the nanomolar range (40±2nm/L) while its production is in the millimolar range/min, with little variation from subject to subject. To determine the precision with which [H(+)]a is regulated during exercise, [H(+)]a, PaCO(2) and ventilation (V˙(E)) were measured during progressively increasing work rate exercise ...

The purpose of the present study was to investigate the relationship between thermoregulation and catecholamine release in the preoptic area and anterior hypothalamus (PO/AH) during incremental treadmill running in the rat. To this aim, we combined in vivo brain microdialysis, biotelemetry and metabolic measurements for continuous monitoring of core body ...

To investigate the effects of different training methods on non-thermal sweating during activation of the muscle metaboreflex, we compared sweating responses during post-exercise muscle occlusion in endurance runners, sprinters, and untrained men under mild hyperthermia (ambient temperature, 35°C; relative humidity, 50%). Ten endurance runners, nine sprinters, and ten untrained men ...

This study examined heat stress, heart rate (HR), fluid balance, micro-environment temperature and humidity with Islamic athletic clothing (IC) compared to traditional soccer uniform (SC). Ratings of perceived exertion (RPE), session RPE (S-RPE), comfort, and cooling response were also examined. Female volunteers (N = 8) completed a treadmill [Formula: see text] test ...

Isometric muscle contraction (static exercise) induces circulatory response. Static exercise in individuals with thoracic spinal cord injury (TSCI) induces cardiovascular response and blood redistribution to the non-exercising muscles. The aim of our study was to determine the circulatory response during arm static exercise in individuals with TSCI and able-bodied (AB) ...

PURPOSE: The aim of this study was to analyze the physiological demands and thermal strain of wildland firefighters during real wildfire suppression. METHODS: The response of core temperature and heart rate (HR) were analyzed in 200 wildland firefighters during wildfire suppression activities of different duration: <1 h (n = 52), 1-3 h (n = 70), 3-5 h ...

Step-up exercise is one of the most commonly utilized exercises during rehabilitation of patients after both anterior cruciate ligament (ACL) injury and reconstruction. Currently, insurance providers increasingly required a trial of intensified rehabilitation before surgical reconstruction is attempted. The purpose of this study was to investigate whether this "safe" rehabilitation ...

HLA-DQB1*02:01:04 differs from DQB1*02:01:01 by one nucleotide (G>A) at position 303 in exon 2 resulting in a silent substitution (codon 69 - GAG >GAA), conserved glutamate.

Muscular blood flow reduction (BFR) during multiple sets of low-intensity exercise training has been shown to elicit muscle hypertrophy and strength gain. Several hypotheses have been proposed to explain the hypertrophic adaptations to low-intensity BFR exercise, which include muscle fatigue with metabolic stress. However, the change in intramuscular inorganic phosphate ...

β-Blocker therapy reduces syncope and sudden death in long-QT syndrome type 1 (LQT1), but the mechanism of protection is incompletely understood. This study tested the hypothesis that β-blockade reduces QT prolongation and dispersion of repolarization, measured as the T peak-to-end interval (T(pe) ), during exercise and recovery in LQT1 patients. ...

The regulation of energy metabolism by the central nervous system during endurance exercise was examined. We conducted respiratory gas analysis by functionally paralyzing the ventromedial hypothalamus (VMH), the lateral hypothalamic area, and the paraventricular nucleus of the hypothalamus with local anaesthetic (lidocaine) during treadmill running at a velocity that allowed ...

The aim of the study was to determine the cardiorespiratory and metabolic characteristics during intense and moderate table tennis (TT) training, as well as during actual match play conditions. Blood lactate concentration (Lac), heart rate (HR, beats per minute [bpm]), oxygen uptake (VO2), and energy expenditure (EE) in 7 male ...

The purpose of the study was to determine the effects of carbohydrate (CHO) intake, with and without protein (PRO), immediately after prolonged strenuous exercise on circulating bacterially stimulated neutrophil degranulation. Twelve male runners completed 3 feeding interventions, 1 week apart, in randomized order after 2 hr of running at 75% ...

In patients with COPD, the degree of functional impairment appears to differ between the upper and lower limbs. Significant dyspnea and fatigue have been reported by these patients when performing tasks with unsupported upper limbs and two mechanisms have been proposed to explain this fact: neuromechanical dysfunction of respiratory muscles; ...

Soccer referees' physical match performances at the start of the second half (46-60 min) were evaluated in relation to both the corresponding phase of the first half (0-15 min) and players' performances during the same match periods. Match analysis data were collected (Prozone, UK) from 12 soccer referees on 152 ...

This study examined the effects of exercise-induced fatigue on soccer skills performed throughout simulated match play. Fifteen academy soccer players completed a soccer match simulation (SMS) including passing, dribbling, and shooting skills. Precision, success rate, and ball speed were determined via video analysis for all skills. Blood samples were obtained ...

Ingesting carbohydrate-electrolyte solutions during exercise has been reported to benefit self-paced time-trial performance. The mechanism responsible for this ergogenic effect is unclear. For example, during short duration (≤1 hour), intense (>70% maximal oxygen consumption) exercise, euglycaemia is rarely challenged and adequate muscle glycogen remains at the cessation of exercise. The ...