Oxidative Stress Response Kinetics after 60 Minutes at Different (1.4 ATA and 2.5 ATA) Hyperbaric Hyperoxia Exposures.

Hyperbaric oxygen therapy (HBOT) is a therapeutical approach based on exposure to pure oxygen in an augmented atmospheric pressure. Although it has been used for years, the exact kinetics of the reactive oxygen species (ROS) between different pressures of hyperbaric oxygen exposure are still not clearly evidenced. In this study, the metabolic responses of hyperbaric hyperoxia exposures for 1 h at 1.

Oxidative Stress Response Kinetics after 60 Minutes at Different Levels (10% or 15%) of Normobaric Hypoxia Exposure.

In this study, the metabolic responses of hypoxic breathing for 1 h to inspired fractions of 10% and 15% oxygen were investigated. To this end, 14 healthy nonsmoking subjects (6 females and 8 males, age: 32.2 ± 13.

Architectural and Mechanical Changes after Five Weeks of Intermittent Static Stretch Training on the Medial Gastrocnemius Muscle of Active Adults.

We investigated the effects of intermittent long-term stretch training (5 weeks) on the architectural and mechanical properties of the muscle-tendon unit (MTU) in healthy humans. MTU's viscoelastic and architectural properties in the human medial gastrocnemius (MG) muscle and the contribution of muscle and tendon structures to the MTU lengthening were analyzed. Ten healthy volunteers participated in the study (four females and six males).

Full-Face Mask Use during SCUBA Diving Counters Related Oxidative Stress and Endothelial Dysfunction.

Impaired flow mediated dilation (FMD), an index of vascular stress, is known after SCUBA diving. This is related to a dysfunction of nitric oxide (NO) availability and a disturbance of the redox status, possibly induced by hyperoxic/hyperbaric gas breathing. SCUBA diving is usually performed with a mask only covering "half face" (HF) and therefore forcing oral breathing.

Hypoxic and Hyperoxic Breathing as a Complement to Low-Intensity Physical Exercise Programs: A Proof-of-Principle Study.

Inflammation is an adaptive response to both external and internal stimuli including infection, trauma, surgery, ischemia-reperfusion, or malignancy. A number of studies indicate that physical activity is an effective means of reducing acute systemic and low-level inflammation occurring in different pathological conditions and in the recovery phase after disease. As a proof-of-principle, we hypothesized that low-intensity workout performed under modified oxygen supply would elicit a "metabolic exercise" inducing a hormetic response, increasing the metabolic load and oxidative stress with the same overall effect expected after a higher intensity or charge exercise.

Effects of noradrenaline and dopamine on supraspinal fatigue in well-trained men.

Purpose: Prolonged exhaustive exercise induces a failure of the nervous system to activate the involved muscles maximally (i.e., central fatigue).

Respiratory rate can be modulated by long-loop muscular reflexes, a possible factor in involuntary cessation of apnea.

Introduction: The main limiting factors determining apnea time are generally considered to be related to blood and cerebrospinal fluid chemistry. Several physiological (adaptive) mechanisms and some psychologic parameters, such as motivation, are also known to increase apnea time.

Aim: We wished to study the link between peripheral muscle fatigue, the concomitant alteration of long latency (transcortical) reflexes and respiratory control.

Initial conditions influence the characteristics of ballistic contractions in the ankle dorsiflexors.

This study investigated the influence of different initial conditions on a subsequent fast (ballistic) isometric contraction of the ankle dorsiflexor muscles. Surface electromyograms (EMGs) of dorsiflexor and plantarflexor muscles were recorded during ballistic contractions performed without any pre-activation (BAL) and in ballistic contractions preceded by a sustained submaximal contraction (20% MVC) that was followed either by a rapid voluntary relaxation of the agonist muscle (VRBAL) or by a rapid antagonist (reversal) contraction (ARBAL). In the latter condition, three different antagonist torque levels were compared (25, 50 and 75% MVC).

Spinal mechanisms contribute to differences in the time to failure of submaximal fatiguing contractions performed with different loads.

This study compared the mechanisms that limit the time to failure of a sustained submaximal contraction at 20% of maximum when the elbow flexors either supported an inertial load (position task) or exerted an equivalent constant torque against a rigid restraint (force task). The surface electromyogram (EMG), the motor-evoked potential (MEP) in response to transcranial magnetic stimulation (TMS) of the motor cortex, and the Hoffmann reflex (H-reflex) and maximal M-wave (Mmax) elicited by electrical stimulation of the brachial plexus were recorded in biceps brachii during the two tasks. Although the time to failure for the position task was only 44% of that for the force task, the rate of increase of the average EMG (aEMG; % initial MVC) and MEP area (% Mmax) did not differ significantly during the two tasks.

Spinal reflexes and coactivation of ankle muscles during a submaximal fatiguing contraction.

This study examined the involvement of spinal mechanisms in the control of coactivation during a sustained contraction of the ankle dorsiflexors at 50% of maximal voluntary contraction. Changes in the surface electromyogram (EMG) of the tibialis anterior and of two antagonist muscles, the soleus and lateral gastrocnemius, were investigated during and after the fatigue task. Concurrently, the compound action potential (M-wave) and the Hoffmann reflex of the soleus and lateral gastrocnemius were recorded.