Alpha band oscillations in common synaptic input are explanatory of the complexity of isometric knee extensor muscle torque signals.

We investigated whether the strength of oscillations in common synaptic input was explanatory of knee extensor (KE) torque signal complexity during fresh and fatigued submaximal isometric contractions, in adults aged from 18 to 90 years. The discharge times of motor units were derived from the vastus lateralis muscle of 60 participants using high-density surface EMG, during 20 s isometric KE contractions at 20% of maximal voluntary contraction, performed before and after a fatiguing repeated isometric KE contraction protocol at 60% of maximal voluntary contraction. Within-muscle coherence Z-scores were estimated using frequency-domain coherence analysis, and muscle torque complexity was assessed using multiscale entropy analysis and detrended fluctuation analysis.

Exercise-induced pain within endurance exercise settings: Definitions, measurement, mechanisms and potential interventions.

Pain can be defined as an unpleasant sensory and emotional experience associated with or resembling that associated with actual or potential tissue damage. Though consistent with this definition, different types of pain result in different behavioural and psychophysiological responses. For example, the transient, non-threatening, acute muscle pain element of exercise-induced pain (EIP) is entirely different from other pain types like delayed onset muscle soreness, muscular injury or chronic pain.

Elevated muscle pain induced by a hypertonic saline injection reduces power output independent of physiological changes during fixed perceived effort cycling.

Pain is a naturally occurring phenomenon that consistently inhibits exercise performance by imposing unconscious, neurophysiological alterations (e.g., corticospinal changes) as well as conscious, psychophysiological pressures (e.

Inter-day reliability of heart rate complexity and variability metrics in healthy highly active younger and older adults.

Purpose: To investigate the inter-day reliability of time-domain, frequency-domain, and nonlinear HRV metrics in healthy highly active younger and older adults. The study also assessed the effect of age on the HRV metrics.

Methods: Forty-four older adults (34 M, 10F; 59 ± 5 years;  = 40.

Functional threshold power and the (manufactured) critical power controversy.

We read with concern yet another communication from Dotan regarding the critical power (CP) concept which contains a litany of factual errors, false statements, and dated physiological interpretations. Space does not permit us to rebut every incorrect point made about our work (Wong et al., 2022) and the wider field in which it sits, but we will address what we consider to be some of the more egregious errors in his letter.

Intra- and interindividual reliability of muscle pain induced by an intramuscular injection of hypertonic saline injection into the quadriceps.

Background: Intramuscular injections of hypertonic saline are commonly used to induce experimental muscle pain, but reliability data on this technique are lacking. This study investigated the intra- and interindividual reliability of pain measures from a hypertonic saline injection into the vastus lateralis.

Methods: Fourteen healthy participants (6 female) attended three laboratory visits where they received an intramuscular injection of 1 mL hypertonic saline into the vastus lateralis.

Reproducibility of NIRS-derived mitochondrial oxidative capacity in highly active older adults.

Introduction: In-vivo techniques using near-infrared spectroscopy (NIRS) have been developed to assess skeletal muscle mitochondrial oxidative capacity. However, the test-retest and day-to-day reliability of NIRS-derived mitochondrial oxidative capacity has yet to be established in older individuals. Therefore, the primary aim of this study was to determine the day-to-day and test-retest reliability of NIRS-derived mitochondrial oxidative capacity in older adults.

Functional threshold power is not a valid marker of the maximal metabolic steady state.

Functional Threshold Power (FTP) has been considered a valid alternative to other performance markers that represent the upper boundary of the heavy intensity domain. However, such a claim has not been empirically examined from a physiological perspective.This study examined the blood lactate and VO response when exercising at and 15 W above the FTP (FTP).

Test-retest reliability of a 30-min fixed perceived effort cycling exercise.

Purpose: Using exercise protocols at a fixed rating of perceived effort (RPE) is a useful method for exploring the psychophysical influences on exercise performance. However, studies that have employed this protocol have arbitrarily selected RPE values without considering how these values correspond to exercise intensity thresholds and domains. Therefore, aligning RPE intensities with established physiological thresholds seems more appropriate, although the reliability of this method has not been assessed.

The effect of hypertonic saline evoked muscle pain on neurophysiological changes and exercise performance in the contralateral limb.

Non-local muscle pain may impair endurance performance through neurophysiological mechanisms, but these are relatively unknown. This study examined the effects of muscle pain on neuromuscular and neurophysiological responses in the contralateral limb. On separate visits, nine participants completed an isometric time to task failure (TTF) using the right knee extensors after intramuscular injection of isotonic saline (CTRL) or hypertonic saline (HYP) into the left vastus lateralis.

The association of end-spurt behaviour with seasonal best time in long-distance freestyle pool swimming.

To analyse the association of seasonal best time, distance and different performance levels with end-spurt behaviour in one swimming season. Race results in 800 and 1500 m pool freestyle swimming in the season 2018/2019 including 14,930 races and 2650 swimmers were obtained. The end-spurt for each race was determined by means of an End-Spurt Indicator (ESI).

The effect of elevated muscle pain on neuromuscular fatigue during exercise.

Purpose: Muscle pain can impair exercise performance but the mechanisms for this are unknown. This study examined the effects of muscle pain on neuromuscular fatigue during an endurance task.

Methods: On separate visits, twelve participants completed an isometric time-to-task failure (TTF) exercise of the right knee extensors at ~ 20% of maximum force following an intramuscular injection of isotonic saline (CTRL) or hypertonic saline (HYP) into the vastus lateralis.

Comparison of Physiological Responses and Muscle Activity During Incremental and Decremental Cycling Exercise.

Objective: To investigate whether a cycling test based on decremental loads (DEC) could elicit higher maximal oxygen uptake (V˙O2max) values compared with an incremental test (INC).

Design: Nineteen well-trained individuals performed an INC and a DEC test on a single day, in randomized order.

Methods: During INC, the load was increased by 20 W·min-1 until task failure.

Pharmacological hypotheses: Is acetaminophen selective in its cyclooxygenase inhibition?

The precise mechanistic action of acetaminophen (ACT; paracetamol) remains debated. ACT's analgesic and antipyretic actions are attributed to cyclooxygenase (COX) inhibition preventing prostaglandin (PG) synthesis. Two COX isoforms (COX1/2) share 60% sequence structure, yet their functions vary.

The influence of environmental and core temperature on cyclooxygenase and PGE2 in healthy humans.

Whether cyclooxygenase (COX)/prostaglandin E2 (PGE2) thermoregulatory pathways, observed in rodents, present in humans? Participants (n = 9) were exposed to three environments; cold (20 °C), thermoneutral (30 °C) and hot (40 °C) for 120 min. Core (Tc)/skin temperature and thermal perception were recorded every 15 min, with COX/PGE2 concentrations determined at baseline, 60 and 120 min. Linear mixed models identified differences between and within subjects/conditions.

Effects of experimentally induced muscle pain on endurance performance: A proof-of-concept study assessing neurophysiological and perceptual responses.

Pain arising from exercise potentiates fatigue and impairs the performance of endurance exercise. We assessed neurophysiological and perceptual responses to endurance exercise performed under experimentally induced muscle pain by a model that separates muscle pain from muscle fatigue. After a series of pilot studies investigating different hypertonic saline volumes, 17 healthy males performed a preliminary VO test before performing a familiarization of the cycling time-to-exhaustion exercise (80% of the peak power output in the VO test).

The effect of tDCS applied to the dorsolateral prefrontal cortex on cycling performance and the modulation of exercise induced pain.

Transcranial direct current stimulation (tDCS) is a neuromodulatory tool purported to enhance endurance performance through reducing fatigue related perceptions, including exercise-induced pain (EIP). We examined whether tDCS of the left DLPFC (1) can reduce EIP during a fixed intensity cycling trial (FI), (2) can improve cycling time trial (TT) performance, and (3) whether this was affected by a bilateral or an extracephalic montage. This investigation was comprised of two parts (study one and two).

Muscle pain from an intramuscular injection of hypertonic saline increases variability in knee extensor torque reproduction.

The intensity of exercise-induced pain (EIP) reflects the metabolic environment in the exercising muscle, so during endurance exercise, this may inform the intelligent regulation of work rate. Conversely, the acute debilitating effects of EIP on motor unit recruitment could impair the estimation of force produced by the muscle and impair judgement of current exercise intensity. This study investigated whether muscle pain that feels like EIP, administered via intramuscular injection of hypertonic saline, interferes with the ability to accurately reproduce torque in a muscle group relevant to locomotive exercise.

Images depicting human pain increase exercise-induced pain and impair endurance cycling performance.

The current study investigated whether viewing images of others in pain influences exercise-induced pain (EIP) and cycling performance. Twenty-one recreational cyclists attended five laboratory visits. The first two visits involved measuring participants' maximal aerobic capacity and familiarized participants to the fixed power (FP) and 16.

Muscle pain induced by hypertonic saline in the knee extensors decreases single-limb isometric time to task failure.

Purpose: Increased nociceptive activity and the experience of exercise-induced pain (EIP) may contribute to fatigue during endurance exercise. To investigate this, a pain model that produces pain similar to EIP and decouples its relationship to exercise intensity is required. This study (1) compared the quality of pain caused by a hypertonic saline injection into the vastus lateralis in resting and exercise conditions, and (2) investigated whether this pain contributes to changes in time to task failure.

Effect of transcranial direct current stimulation on exercise performance: A systematic review and meta-analysis.

Background: Transcranial direct current stimulation (tDCS) has been used to improve exercise performance, though the protocols used, and results found are mixed.

Objective: We aimed to analyze the effect of tDCS on improving exercise performance.

Methods: A systematic search was performed on the following databases, until December 2017: PubMed/MEDLINE, Embase, Web of Science, SCOPUS, and SportDiscus.

The Effect of Anodal Transcranial Direct Current Stimulation Over Left and Right Temporal Cortex on the Cardiovascular Response: A Comparative Study.

Stimulation of the right and left anterior insular cortex, increases and decreases the cardiovascular response respectively, thus indicating the brain's lateralization of the neural control of circulation. Previous experiments have demonstrated that transcranial direct current stimulation (tDCS) modulates the autonomic cardiovascular control when applied over the temporal cortex. Given the importance of neural control for a normal hemodynamic response, and the potential for the use of tDCS in the treatment of cardiovascular diseases, this study investigated whether tDCS was capable of modulating autonomic regulation.

Prescribing 6-weeks of running training using parameters from a self-paced maximal oxygen uptake protocol.

Purpose: The self-paced maximal oxygen uptake test (SPV) may offer effective training prescription metrics for athletes. This study aimed to examine whether SPV-derived data could be used for training prescription.

Methods: Twenty-four recreationally active male and female runners were randomly assigned between two training groups: (1) Standardised (STND) and (2) Self-Paced (S-P).