Acute L-Citrulline Supplementation Increases Nitric Oxide Bioavailability but Not Inspiratory Muscle Oxygenation and Respiratory Performance

The present study aimed to investigate whether acute L-citrulline supplementation would affect inspiratory muscle oxygenation and respiratory performance. Twelve healthy males received 6 g of L-citrulline or placebo in a double-blind crossover …

Physiological indicators of task demand, fatigue, and cognition in future digital manufacturing environments

As Digital Manufacturing transforms traditionally physical work into more system-monitoring tasks, new methods are required for understanding people's mental workload and prolonged capacity for focused attention. Many physiological measures have …

Sequential Pulse Compression's Effect on Blood Flow in the Lower-Extremity

CONTEXT: Several interventions are available to reduce the intensity and duration of the unwanted effects (eg, muscle soreness) associated with physical activity, such as massage, compression garments, and sequential pulse compression (SPC). Such …

Electrically evoked wrist extensor muscle fatigue throughout repetitive motion as measured by mechanomyography and near-infrared spectroscopy

Repetitive electrically-evoked muscle contraction leads to accelerated muscle fatigue. This study assessed electrically-evoked fatiguing muscle with changes to mechanomyography root mean square percentage (%RMS-MMG) and tissue saturation index (%TSI) …

Muscle oxygenation induced by cycling exercise does not accelerate recovery kinetics following exercise-induced muscle damage in humans: A randomized cross-over study

The aim of this study was to analyze the effects of inducing muscle oxygenation using an intermittent cycling exercise on recovery kinetics after exercise-induced muscle damage. Ten soccer players performed single-leg knee flexors exercise: 75 …

Relationship between muscle metabolic rate and muscle torque complexity during fatiguing intermittent isometric contractions in humans

To test the hypothesis that a system's metabolic rate and the complexity of fluctuations in the output of that system are related, thirteen healthy participants performed intermittent isometric knee extensor contractions at intensities where a rise …

Fatigability, oxygen uptake kinetics and muscle deoxygenation in incomplete spinal cord injury during treadmill walking

Purpose: The purpose of the present study was to characterize hypothesized relationships among fatigability and cardiorespiratory fitness in individuals with chronic motor-incomplete SCI (iSCI) during treadmill walking. The theoretical framework was …

Mitochondrial capacity, muscle endurance, and low energy in friedreich ataxia

Introduction: In this study we noninvasively evaluated skeletal muscle mitochondrial capacity, muscle-specific endurance, and energy/fatigue feelings in persons with Friedreich ataxia (FRDA) and able-bodied controls (AB). Methods: Forearm …

Ischemic preconditioning reduces hemodynamic response during metaboreflex activation

Ischemic preconditioning (IP) has been shown to improve exercise performance and to delay fatigue. However, the precise mechanisms through which IP operates remain elusive. It has been hypothesized that IP lowers the sensation of fatigue by reducing …

Cold-water immersion decreases cerebral oxygenation but improves recovery after intermittent-sprint exercise in the heat

This study examined the effects of post-exercise cooling on recovery of neuromuscular, physiological, and cerebral hemodynamic responses after intermittent-sprint exercise in the heat. Nine participants underwent three post-exercise recovery trials, …

Knee extensor fatigue threshold is related to whole-body V̇O 2max

Purpose: Above a given exercise intensity, rapid muscle fatigue will occur. We explored the possibility of assessing torque threshold for peripheral fatigue during single-legged repetitive isometric knee extensor exercise. We hypothesized this …

Does cerebral oxygen delivery limit incremental exercise performance?

Previous studies have suggested that a reduction in cerebral oxygen delivery may limit motor drive, particularly in hypoxic conditions, where oxygen transport is impaired. We hypothesized that raising end-tidal PCO 2 (PETCO 2) during incremental …

Frontal and motor cortex oxygenation during maximal exercise in normoxia and hypoxia

Reductions in prefrontal oxygenation near maximal exertion may limit exercise performance by impairing executive functions that influence the decision to stop exercising; however, whether deoxygenation also occurs in motor regions that more directly …

Cerebrovascular responses to incremental exercise during hypobaric hypoxia: Effect of oxygenation on maximal performance

We sought to describe cerebrovascular responses to incremental exercise and test the hypothesis that changes in cerebral oxygenation influence maximal performance. Eleven men cycled in three conditions: 1) sea level (SL); 2) acute hypoxia [AH; …

Effects of acute hypoxia on cerebral and muscle oxygenation during incremental exercise

To determine if fatigue at maximal aerobic power output was associated with a critical decrease in cerebral oxygenation, 13 male cyclists performed incremental maximal exercise tests (25 W/min ramp) under normoxic (Norm: 21% FIO2) and acute hypoxic …

The isometric torque at which knee-extensor muscle reoxygenation stops

PURPOSE: We investigated the knee-extensor torque at which reoxygenation (inflow of arterial blood) during an isometric contraction stopped, whether this torque depended on maximal torque capacity (MTC), and whether there were differences among the …

Knee angle-dependent oxygen consumption during isometric contractions of the knee extensors determined with near-infrared spectroscopy

Fatigue resistance of knee extensor muscles is higher during voluntary isometric contractions at short compared with longer muscle lengths. In the present study we hypothesized that this would be due to lower energy consumption, at short muscle …