COVID-19-Associated Multisystem Inflammatory Syndrome in Children and Cardiovascular Autonomic Control: A Prospective Cohort Study Nine Months after SARS-CoV-2 Infection.

Multisystem Inflammatory Syndrome in Children (MIS-C) has emerged as a severe pediatric complication during the SARS-CoV-2 pandemic, with potential long-term cardiovascular repercussions. We hypothesized that heart rate and blood pressure control at rest and during postural maneuvers in MIS-C patients, months after the remission of the inflammatory syndrome, may reveal long-term autonomic dysfunctions. We assessed 17 MIS-C patients (13 males; 11.

Synergistic difference in the effect of stretching on electromechanical delay components.

This study investigated the synergistic difference in the effect of stretching on electromechanical delay (EMD) and its components, using a simultaneous recording of electromyographic, mechanomyographic, and force signals. Twenty-six healthy men underwent plantar flexors passive stretching. Before and after stretching, the electrochemical and mechanical components of the EMD and the relaxation EMD (R-EMD) were calculated in gastrocnemius medialis (GM), lateralis (GL) and soleus (SOL) during a supramaximal motor point stimulation.

Energetics of sinusoidal exercise below and across critical power and the effects of fatigue.

Purpose: Previous studies investigating sinusoidal exercise were not devoted to an analysis of its energetics and of the effects of fatigue. We aimed to determine the contribution of aerobic and anaerobic lactic metabolism to the energy balance and investigate the fatigue effects on the cardiorespiratory and metabolic responses to sinusoidal protocols, across and below critical power (CP).

Methods: Eight males (26.

Speed Effects on the Accuracy of Heart Rate as Oxygen-Uptake Indicator in Short-Distance Shuttle Running.

Despite the accuracy of heart rate (HR) as an indicator of the aerobic engagement has been evaluated in several intermittent on-court activities, its validity as an oxygen uptake () indicator during shuttle running over short paths remains uncertain. Moreover, it is unclear whether speed may affect such validity. This study evaluated the HR ability in estimating the during 5-m shuttle running at different speeds.

Gait Variability at Different Walking Speeds.

Gait variability (GV) is a crucial measure of inconsistency of muscular activities or body segmental movements during repeated tasks. Hence, GV might serve as a relevant and sensitive measure to quantify adjustments of walking control. However, it has not been clarified whether GV is associated with walking speed, a clarification needed to exploit effective better bilateral coordination level.

Is the Interpolated-Twitch Technique-Derived Voluntary Activation Just Neural? Novel Perspectives from Mechanomyographic Data.

Purpose: Voluntary activation (VA) determined by interpolation-twitch technique could be affected by the characteristics of the in-series elastic components. To overcome this possible bias, a novel approach based on the mechanomyographic (MMG) signal to detect voluntary activation (VA MMG ) has been proposed. We examined the changes in VA and VA MMG after passive stretching to check the influence of neural and mechanical factors in the force output.

Determining voluntary activation in synergistic muscles: a novel mechanomyographic approach.

Purpose: Drawing on correlations between the mechanomyographic (MMG) and the force signal, we devised a novel approach based on MMG signal analysis to detect voluntary activation (VA) of the synergistic superficial heads of the quadriceps muscle. We hypothesized that, after a fatiguing exercise, the changes in the evoked MMG signal of each quadriceps head would correlate with the changes in the level of VA in the whole quadriceps.

Methods: Twenty-five men underwent a unilateral single-leg quadriceps exercise to failure.

Passive stretching decreases muscle efficiency in balance tasks.

The current study aimed to verify whether or not passive static stretching affects balance control capacity. Thirty-eight participants (19 women and 19 men) underwent a passive static stretching session, involving the knee extensor/flexor and dorsi/plantarflexor muscles, and a control session (no stretching, CTRL). Before (PRE), immediately after (POST), after 15 (POST15) and 30 min (POST30) from stretching (or rest in CTRL), balance control was evaluated under static and dynamic conditions, with open/closed eyes, and with/without somatosensory perturbation (foam under the feet).

Training status affects between-protocols differences in the assessment of maximal aerobic velocity.

Purpose: Continuous incremental protocols (CP) may misestimate the maximum aerobic velocity (V) due to increases in running speed faster than cardiorespiratory/metabolic adjustments. A higher aerobic capacity may mitigate this issue due to faster pulmonary oxygen uptake ([Formula: see text]O) kinetics. Therefore, this study aimed to compare three different protocols to assess V in athletes with higher or lower training status.

No effect of passive stretching on neuromuscular function and maximum force-generating capacity in the antagonist muscle.

Purpose: The present study investigated whether or not passive stretching increases the force-generating capacity of the antagonist muscle, and the possible neuromuscular mechanisms behind.

Methods: To this purpose, the neuromuscular function accompanying the force-generating capacity was assessed in 26 healthy male volunteers after passive stretching and in a control session. Before and after passive intermittent static stretching of the plantar flexors consisting of five sets × 45 s + 15 s-rest, maximum voluntary isometric contraction (MVC) and surface electromyographic root mean square (sEMG RMS) were measured in the tibialis anterior (the antagonist muscle).

The effects of 12 weeks of static stretch training on the functional, mechanical, and architectural characteristics of the triceps surae muscle-tendon complex.

Purpose: We investigated the effects of 12 weeks of passive static stretching training (PST) on force-generating capacity, passive stiffness, muscle architecture of plantarflexor muscles.

Methods: Thirty healthy adults participated in the study. Fifteen participants (STR, 6 women, 9 men) underwent 12-week plantarflexor muscles PST [(5 × 45 s-on/15 s-off) × 2exercises] × 5times/week (duration: 2250 s/week), while 15 participants (CTRL, 6 women, 9 men) served as control (no PST).

Testing protocol affects the velocity at VO in semi-professional soccer players.

To compare three different protocols to assess the velocity associated with the maximal oxygen uptake (V) in soccer players. Sixteen semi-professional soccer players performed three maximum incremental tests on treadmill: two continuous protocols [1 km·h·min (CP1); and 1 km·h every 2 min (CP2)], and one discontinuous (DP) protocol to determine V, maximum oxygen uptake (VO) and oxygen cost of running (i.e.

Complexity Analysis of Surface Electromyography for Assessing the Myoelectric Manifestation of Muscle Fatigue: A Review.

The surface electromyography (sEMG) records the electrical activity of muscle fibers during contraction: one of its uses is to assess changes taking place within muscles in the course of a fatiguing contraction to provide insights into our understanding of muscle fatigue in training protocols and rehabilitation medicine. Until recently, these myoelectric manifestations of muscle fatigue (MMF) have been assessed essentially by linear sEMG analyses. However, sEMG shows a complex behavior, due to many concurrent factors.

Acute carnosine and β-alanine supplementation increase the compensated part of the ventilation versus work rate relationship during a ramp incremental cycle test in physically active men.

Background: Chronic supplementation with carnosine and β-alanine (Carn-βA) has been proposed to improve muscle contractility and reduce muscle fatigue mainly through an increase in intracellular pH buffering capacity. However, the acute ergogenic effects of Carn-βA supplementation are poorly investigated. This study aimed at evaluating the acute effects of a single Carn-βA supplementation on the cardiorespiratory and metabolic response during a ramp cycle-ergometric test.

Area per player in small-sided games to replicate the external load and estimated physiological match demands in elite soccer players.

The current study determined the area-per-player during small- or large-sided games with or without goalkeeper that replicates the relative (m·min-1) total distance, high-intensity running distance, sprint distance and metabolic power covered during official matches. Time-motion analysis was performed on twenty-five elite soccer-players during 26 home-matches. A total of 2565 individual samples for SSGs using different pitch sizes and different number of players were collected and classified as SSGs with (SSG-G) or without goalkeeper (SSG-P).

On-Sight and Red-Point Climbing: Changes in Performance and Route-Finding Ability in Male Advanced Climbers.

Aim: In lead climbing, the ascent of the route can be defined as on-sight or red-point. On-sight is the more challenging style since it demands greater physiological and psychological commitment. The differences between the two modes in advanced climbers have not been studied much.

Local fat content and muscle quality measured by a new electrical impedance myography device: correlations with ultrasound variables.

The present study investigated the relationship between local fat percentage (SK) and muscle quality (MQ) estimated by a new hand-held electrical impedance myography (EIM) device or derived from ultrasound and strength assessments. The right anterior thigh of 90 healthy participants (mean ± SD; age=22.9 ± 2.

Impaired heart rate recovery after sub-maximal physical exercise in people with multiple sclerosis.

Background: Heart Rate Recovery (HRR) after a physical exercise has been poorly investigated in people with multiple sclerosis (PwMS).

Objective: To evaluate the kinetics of HRR and its autonomic modulation in PwMS and to elucidate the interplay between HRR and subjective fatigue.

Methods: ECG was digitally acquired during rest (5 min), submaximal exercise (4 min at 10 W of upper limb cycling) and recovery (3 min) in 17 PwMS (EDSS: 5.

Neuromuscular versus Mechanical Stretch-induced Changes in Contralateral versus Ipsilateral Muscle.

Purpose: Whether or not the homologous contralateral muscle (CM) undergoes stretch-induced force reduction as the stretched muscle (SM) is still unclear. The neuromuscular and mechanical factors underlying the force reduction in CM and SM were investigated.

Methods: Twenty-one participants underwent unilateral knee extensors passive stretching.

Peripheral fatigue: new mechanistic insights from recent technologies.

Peripheral fatigue results from multiple electrochemical and mechanical events in the cell body and the muscle-tendon complex. Combined force and surface electromyographic signal analysis is among the most widely used approaches to describe the behaviour of a fatigued muscle. Advances in technologies and methodological procedures (e.

Quadriceps and Gastrocnemii Anatomical Cross-Sectional Area and Vastus Lateralis Fascicle Length Predict Peak-Power and Time-To-Peak-Power.

: The current study investigated the role of quadriceps and gastrocnemii size and and muscle architecture in peak-power and time-to-peak-power exerted in an all-out Wingate test. Twenty-one amateur cyclists were recruited. : Quadriceps and gastrocnemii anatomical cross-sectional area (ACSA), and and pennation angle and fascicle length were measured using ultrasound.

Evidence of Improved Vascular Function in the Arteries of Trained but Not Untrained Limbs After Isolated Knee-Extension Training.

Vascular endothelial function is a strong marker of cardiovascular health and it refers to the ability of the body to maintain the homeostasis of vascular tone. The endothelial cells react to mechanical and chemical stimuli modulating the smooth muscle cells relaxation. The extent of the induced vasodilation depends on the magnitude of the stimulus.

Heart and musculoskeletal hemodynamic responses to repetitive bouts of quadriceps static stretching.

The role of sympathetic and parasympathetic activity in relation to the repetitive exposure to static stretching (SS) on heart and musculoskeletal hemodynamics in stretched and resting muscles is still a matter of debate. The aim of the study was to determine cardiac and musculoskeletal hemodynamics to repetitive bouts of unilateral SS. Sympathetic and parasympathetic activity contribution to the central hemodynamics and local difference in circulation of stretched and resting muscles were also investigated.

Kinematic effects of repeated turns while running.

In team sports, non-contact ACL and MCL injuries occur during abrupt changes of direction, like turns or cutting manoeuvres. Fatigue affects dynamic neuromuscular control and increases knee injury risk. This study analysed how lower limb joints and centre-of-mass kinematics are affected throughout a high-intensity running protocol involving repeated 180°-turns.

Effect of ramp slope on different methods to determine lactate threshold in semi-professional soccer players.

The present study aimed to investigate the effect of stage duration in incremental protocols on lactate threshold (LT), determined by different methods. Sixteen semi-professional soccer-players performed a 4-min stage incremental discontinuous (DP) and two maximal incremental running continuous (1 km h· min, CP1; and 1 km h·2 min CP2) protocols. Blood-lactate concentration [La] was measured at baseline and during the protocols.