The short-term scaling exponent of detrended fluctuation analysis (DFAα1) applied to interbeat intervals may provide a method to identify ventilatory thresholds and indicate systemic perturbation during prolonged exercise. The purposes of this study were to (i) identify the gas exchange threshold (GET) and respiratory compensation point (RCP) using DFAα1 values of 0.75 and 0.5 from incremental exercise, (ii) compare DFAα1 thresholds with DFAα1 measures during constant-speed running near the maximal lactate steady state (MLSS), and (iii) assess the repeatability of DFAα1 between MLSS trials. Twelve runners performed an incremental running test and constant-speed running 5% below, at, and 5% above the MLSS, plus a repeat trial at MLSS. During 30-min running trials near MLSS, DFAα1 responses were variable (i.e., 0.27-1.24) and affected by intensity (p = 0.031) and duration (p = 0.003). No difference in DFAα1 was detected between MLSS trials (p = 0.597). In the early phase (~ 8 min), DFAα1 measures at MLSS (0.71 [0.13]) remained higher than the DFAα1 identified at RCP from the incremental test (0.57 [0.13]; p = 0.024). In addition, following ~ 18 min of constant speed running at MLSS, DFAα1 measures (0.64 [0.14]) remained higher than 0.5 (p = 0.011)-the value thought to demarcate the boundaries between heavy and severe exercise intensities. Accordingly, using fixed DFAα1 values associated with the RCP from incremental exercise to guide constant-speed exercise training may produce a greater than expected exercise intensity, however; the dependency of DFAα1 on intensity and duration suggest its potential utility to quantify systemic perturbations imposed by continuous exercise.

Despite the well-documented benefits of sprint interval training (SIT) and plyometric training (PT) in improving the physical fitness of soccer players, it remains unclear which of these training methods is superior for enhancing players\' aerobic and anaerobic performance. Therefore, this study aimed to compare the effects of SIT and PT on physical performance measures of male soccer players. Thirty male soccer players were randomly assigned to PT (n = 10), SIT (n = 10), and an active control group (CON, n = 10). Before and after the training period, participants underwent a battery of tests consisting of vertical jump, Wingate, linear sprint with and without ball dribbling, change of direction, ball kick, and the Yo-Yo intermittent recovery level 1 (Yo-Yo IR1) tests. Both groups exhibited similar improvements in maximal kicking distance (PT, effect size [ES] = 0.68; SIT, ES = 0.92) and measures of aerobic fitness including maximum oxygen uptake (PT, ES = 1.24; SIT, ES = 1.26) and first (PT, ES = 0.85; SIT, ES = 1.08) and second (PT, ES = 0.86; SIT, ES = 0.98) ventilatory thresholds. However, PT intervention resulted in greater changes in vertical jump (ES = 1.72 vs. 0.82, p = 0.001), anaerobic power (peak power, ES = 1.62 vs. 0.97, p = 0.009; mean power, ES = 1.15 vs. 1.20, p = 0.05), linear speed (20-m, ES = -1.58 vs. -0.98, p = 0.038; 20-m with ball, ES = -0.93 vs. 0.71, p = 0.038), and change of direction ability (ES = -2.56 vs. -2.71, p = 0.046) than SIT. In conclusion, both PT and SIT demonstrated effectiveness in enhancing aerobic performance among male soccer players. However, PT yielded superior improvements in anaerobic power, vertical jump, linear speed, and change of direction performance compared to SIT. These findings suggest that PT may offer additional benefits beyond aerobic conditioning.

UNASSIGNED: The modern fitness culture, propelled by celebrity influence and media exposure, has led to widespread acceptance and consumption of protein supplements, particularly among young adult males aspiring for an ideal physique. Despite the surge in usage, limited research has explored the impact of these supplements on cardiovascular health and exercise performance. This study aims to bridge this gap by clinically examining the cardiovascular system using heart rate variability (HRV) and comparing outcomes between those using protein supplements and a control group.
UNASSIGNED: This study was conducted at the Department of Physiology, AIIMS Raipur. The cross-sectional study involved 60 young adult males aged 18-25 years. Participants were divided into two groups: group I (n = 30), comprising individuals using commercially available protein supplements for a minimum of three months, and group II (n = 30) as age-matched controls. Cardiovascular assessments, including HRV analysis, were performed at rest and after the Harvard step test. Pre-exercise and post-exercise parameters were statistically analyzed, and participants in the test group provided information on supplement labels.
UNASSIGNED: Participants in both groups exhibited comparable pre-exercise cardiovascular parameters. However, post-exercise results did not reveal significant variations in systolic blood pressure, diastolic blood pressure, mean blood pressure, low frequency/high frequency (LF/HF) ratio, Standard deviation of the successive differences between adjacent NNs (SDNN), and standard deviation of successive differences (SDSD) between the test and control groups. The average exercise duration for the control group was longer than that of the test group. Amino acid profiles and nutritional content varied among 13 different protein supplement brands.
UNASSIGNED: The study found no statistically significant positive influence of protein supplements on cardiovascular health or exercise performance in young adult males.

Sialyllactose (SL) is a functional human milk oligosaccharide essential for immune support, brain development, intestinal maturation, and antiviral defense. However, despite its established health benefits, the effect of SL on exercise performance and muscle mass in mice remains unknown. Here, we aimed to investigate, for the first time, the effects of 6\'-SL on muscle functions. Seven-week-old male C57BL/6J mice were administered 100 mg/kg 6\'-SL for 12 weeks, after which exhaustive treadmill performance was conducted. Moreover, muscle strength was examined by grip strength, and muscle phenotype characteristics such as muscle mass, muscle fiber size, and muscle protein expression were also examined. The administration of 6\'-SL significantly improved exhaustive treadmill performance metrics, including distance and exhaustion time. Grip strength was also increased by 6\'-SL administration. Additionally, 6\'-SL increased muscle mass in both the gastrocnemius (GAS) and soleus. 6\'-SL administration led to an increase in the minimum Feret\'s diameter and the protein expression of total myosin heavy chain in the GAS muscle. In conclusion, 6\'-SL administration in vivo led to increased running distance and time by increasing muscle mass and strength. These findings collectively indicate that 6\'-SL is a potential agent for improving muscle health and exercise performance.

Maximal oxygen uptake (VO2max) is a determining indicator for cardiorespiratory capacity in endurance athletes, and epigenetics is crucial in its levels and variability. This initial study examined a broad plasma miRNA profile of twenty-three trained elite endurance athletes with similar training volumes but different VO2max in response to an acute maximal graded endurance test. Six were clustered as higher/lower levels based on their VO2max (75.4 ± 0.9 and 60.1 ± 5.0 mL.kg-1.min-1). Plasma was obtained from athletes before and after the test and 15 ng of total RNA was extracted and detected using an SYBR-based 1113 miRNA RT-qPCR panel. A total of 51 miRNAs were differentially expressed among group comparisons. Relative amounts of miRNA showed a clustering behavior among groups regarding distinct performance/time points. Significantly expressed miRNAs were used to perform functional bioinformatic analysis (DIANA tools). Fatty acid metabolism pathways were strongly targeted for the significantly different miRNAs in all performance groups and time points (p < 0.001). Although this pathway does not solely determine endurance performance, their significant contribution is certainly achieved through the involvement of miRNAs. A highly genetically dependent gold standard variable for performance evaluation in a homogeneous group of elite athletes allowed genetic/epigenetic aspects related to fatty acid pathways to emerge.

The concept of the \"central governor\" in exercise physiology suggests the brain plays a key role in regulating exercise performance by continuously monitoring physiological and psychological factors. In this case report, we monitored, for the first time, a marathon runner using a metabolic portable system and an EEG wireless device during an entire marathon to understand the influence of brain activity on performance, particularly the phenomenon known as \"hitting the wall\". The results showed significant early modification in brain activity between the 10th and 15th kilometers, while the RPE remained low and cardiorespiratory responses were in a steady state. Thereafter, EEG responses decreased after kilometer 15, increased briefly between kilometers 20 and 25, then continued at a slower pace. After kilometer 30, both speed and respiration values dropped, along with the respiratory exchange ratio, indicating a shift from carbohydrate to fat metabolism, reflecting glycogen depletion. The runner concluded the race with a lower speed, higher RPE (above 15/20 on the Borg RPE scale), and reduced brain activity, suggesting mental exhaustion. The findings suggest that training strategies focused on recognizing and responding to brain signals could allow runners to optimize performance and pacing strategies, preventing premature exhaustion and improving overall race outcomes.

Lactate is an important energy intermediate and metabolic buffer, and may be ergogenic. We investigated if lactate supplementation is an effective approach to enhance the exercise performance and acid-base balance of trained cyclists during exercise devised to simulate the demands of endurance road race cycling. Sixteen endurance-trained male cyclists (V·O2max 59 ± 7 mL·kg-1·min-1) consumed 120 mg·kg-1 body mass of lactate or a placebo 70 min prior to performing an exercise performance test, comprising five repeated blocks consisting of 1 km and 4 km time trials interspersed with 10 min of moderate-intensity exercise. Blood acid-base balance (including [H+] and [HCO3-]), heart rate, perceived exertion, and gastro-intestinal tolerance were assessed. There was no effect of lactate supplementation on exercise performance (p = 0.320), despite a reduction in RPE (p = 0.012) and increases in [SID] (p = 0.026) and [HCO3-] (p = 0.041). In addition, gastro-intestinal side effects were observed, but there was no effect on heart rate. Lactate supplementation did not improve exercise performance, despite positive changes in acid-base balance and RPE. This suggests that the alkalising effects of the supplement can reduce perceived effort, but these benefits do not translate into performance improvements.

Modulation of testing conditions such as resting lactate (Larest) levels or carbohydrate intake may affect the calculation of the maximal glycolytic rate (νLa.max). To evaluate the impact of elevated Larest as well as reduced and increased carbohydrate availability on νLa.max in running sprints (RST), twenty-one participants completed five 15-s RST tests on a running track under five different conditions: (I). baseline: Larest ≤1.5 mmol·L-1; (II). Lactate+: Larest ≥2.5 mmol·L-1; (III). CHO-: carbohydrate intake: ≤ 1 g·kg-1 BW d-1 for 3 days; (IV). CHO+: carbohydrate intake: ≥ 9 g·kg-1 BW d-1 for one day; and (V). acuteCHO: 500 mL glucose containing beverage consumed before RST. νLa.max was significantly reduced in lactate+ and CHO- conditions compared to the baseline RST, due to a reduction in the arithmetic mean delta (∆) between Lapeak and Larest lactate concentration (Lapeak, mmol · L-1). AcuteCHO led to an increase in Larest compared to baseline, CHO- and CHO+ with a high interindividual variability but did not significantly reduce νLa.max. Therefore, avoiding low carbohydrate nutrition before νLa.max testing, along with carefully adjusting Larest to below ≤1.5 mmol·L-1, is crucial to prevent the unintentional underestimation of νLa.max.

Increasing evidence suggests that activation of muscle nerve afferents may inhibit central motor drive, affecting contractile performance of remote exercising muscles. Although these effects are well documented for metaboreceptors, very little is known about the activation of mechano- and mechanonociceptive afferents on performance fatigability. Therefore, the purpose of the present study was to examine the influence of mechanoreceptors and nociceptors on performance fatigability. Eight healthy young males undertook four randomized experimental sessions on separate occasions in which the experimental knee extensors were the following: 1) resting (CTRL), 2) passively stretched (ST), 3) resting with delayed onset muscle soreness (DOMS), or 4) passively stretched with DOMS (DOMS+ST), whereas the contralateral leg performed an isometric time to task failure (TTF). Changes in maximal voluntary contraction (ΔMVC), potentiated twitch force (ΔQtw,pot), and voluntary muscle activation (ΔVA) were also assessed. TTF was reduced in DOMS+ST (-43%) and ST (-29%) compared with CTRL. DOMS+ST also showed a greater reduction of VA (-25% vs. -8%, respectively) and MVC compared with CTRL (-28% vs. -45%, respectively). Rate of perceived exertion (RPE) was significantly increased at the initial stages (20-40-60%) of the TTF in DOMS+ST compared with all conditions. These findings indicate that activation of mechanosensitive and mechanonociceptive afferents of a muscle with DOMS reduces TTF of the contralateral homologous exercising limb, in part, by reducing VA, thereby accelerating mechanisms of central fatigue.NEW & NOTEWORTHY We found that activation of mechanosensitive and nociceptive nerve afferents of a rested muscle group experiencing delayed onset muscle soreness was associated with reduced exercise performance of the homologous exercising muscles of the contralateral limb. This occurred with lower muscle voluntary activation of the exercising muscle at the point of task failure.

Chlorich®EnergyBoost, a water extract obtained from Chlorella sorokiniana, has been proposed to enhance physical performance and provide anti-fatigue effects. This study assessed the impact of Chlorich®EnergyBoost supplementation on physical performance and its anti-fatigue properties. Twenty-four mice were allocated into four groups: (1) the control group receiving only water,;(2) the 1X group (49.2 mg/kg/day); (3) the 2X group (98.4 g/kg/day); and (4) the 5X group (246 g/kg/day). All groups were orally administered the supplements for four consecutive weeks. The evaluation included grip strength, swimming endurance, an exhaustion test, and serum biochemistry analysis. Additionally, the study examined the bioactive peptides through matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS) and conducted bacterial reverse mutation and acute oral toxicity tests for safety assessment. The findings indicated that Chlorich®EnergyBoost supplementation led to a significant reduction in serum lactate levels by 14.08% to 22.54% and blood urea nitrogen levels by 12.23% to 16.76%, an increase in the lactate clearance rate by 0.28 to 0.35, an enhancement of muscle glycogen storage by 1.10 to 1.44-fold, and hepatic glycogen storage by 1.41 to 1.47-fold. These results demonstrated dose-dependent effects. MALDI-TOF analysis revealed the expression of dihydrolipoamide dehydrogenase and superoxide dismutase. Both the bacterial reverse mutation and acute oral toxicity tests showed no adverse effects.