Volitional Exhaustion Research Articles

Maximal incremental exercise improves macular photostress recovery time and lowers intraocular pressure in healthy athletes

ObjectivesBetter visual performance in athletes compared to non-athletes could suggest improved macular function through physical exertion. The study aimed to investigate the effect of maximal incremental treadmill (MIT) exercise on macular function. DesignAn interventional study comparing the effect of maximal incremental treadmill (MIT) exercise until volitional exhaustion between athletes (n = 26) and non-athletes (n = 26). MethodsParticipants underwent an ophthalmological assessment involving repeated measurements of the photostress recovery time (PSRT) at baseline and post-exercise. PSRT was recorded after a 10-second exposure of the macular to an intense light source from an ophthalmoscope positioned 2 cm in front of the eye. Secondary outcome measures also recorded included the best-corrected visual acuity (BCVA) and the intraocular pressure (IOP). ResultsCompared to the baseline, MIT exercise markedly improved the PSRT of athletes from 42.7 ± 1.6 s to 39.6 ± 1.4 s (P < 0.001), while having no significant changes in the PSRT of non-athletes. After adjusting for exercise duration, the exercise intervention showed significant effects on the PSRT improvement in the athletes compared to non-athletes after exercise [F(1,49) = 16.941, P < 0.001], with estimated marginal means of 3.00 s and 0.47 s, respectively. Also, the exercise intervention resulted in significant improvements in IOP (P < 0.001) and BCVA (P < 0.01) of both groups. ConclusionsMIT exercise improves macular function, BCVA, and reduced IOP in healthy athletes. Maximal incremental exercise may be recommended for competitive sports athletes seeking optimal visual performance, as long as it does not adversely impact other relevant non-visual factors.

Electroencephalography spectral coherence analysis during cycle ergometry in low- and high-tolerant individuals.

The main objective of this study was to further understanding of the patterns of spectral connectivity during exercise in low- and high-tolerant individuals. Thirty-nine healthy individuals (i.e., 17 low- and 22 high-tolerant participants) took part in the present study. A state-of-the-art portable electroencephalography system was used to measure the brain's electrical activity during an incremental exercise test performed until the point of volitional exhaustion on a cycle ergometer. Spectral coherence was used to explore the patterns of connectivity in the frontal, central, and parietal regions of the brain. Physiological, perceptual, and affective responses were assessed throughout the exercise bout. The spontaneous eyeblink rate was also calculated prior to commencement and upon completion of the exercise trial as an indirect assessment of the dopaminergic system. The present findings indicate that high-tolerant individuals reported lower levels of perceived activation, especially during the preliminary stages of the exercise test. Participants in the high-tolerance group also reported greater levels of remembered pleasure upon completion of the exercise test. The data also revealed that high-tolerant individuals exhibited increased connectivity of theta waves between frontal, central, and parietal electrode sites and increased connectivity of beta waves, primarily within the parietal cortex. Correlational analysis indicated the possibility that low- and high-tolerant individuals make use of different neural networks to process and regulate their psychophysiological state during exercise-related situations. This strategy could potentially represent a conscious decision to downregulate affective arousal and facilitate the neural control of working muscles during situations of physical stress.

Stroke and physiological relationships during the incremental front crawl test: outcomes for planning and pacing aerobic training.

Purpose: This study aimed to evaluate the physiological responses associated with the stroke length (SL) and stroke rate (SR) changes as swimming velocity increases during an incremental step-test. Moreover, this study also aimed to verify if SL and SR relationships toward maximal oxygen uptake (V̇O2max), gas respiratory compensation point (RCP), exchange threshold (GET), and swimming cost can be applied to the management of endurance training and control aerobic pace. Methods: A total of 19 swimmers performed the incremental test until volitional exhaustion, with each stage being designed by percentages of the 400m (%v400) maximal front crawl velocity. V̇O2max, GET, RCP, and the respective swimming velocities (v) were examined. Also, the stroke parameters, SL, SR, the corresponding slopes (SLslope and SRslope), and the crossing point (Cp) between them were determined. Results: GET and RCP corresponded to 70.6% and 82.4% of V̇O2max (4185.3 ± 686.1mLmin-1), and V̇O2 at Cp, SLslope, and SRslope were observed at 129.7%, 75.3%, and 61.7% of V̇O2max, respectively. The swimming cost from the expected V̇O2 at vSLslope (0.85 ± 0.18kJm-1), vSRslope (0.77 ± 0.17kJm-1), and vCp (1.09 ± 0.19kJm-1) showed correlations with GET (r = 0.73, 0.57, and 0.59, respectively), but only the cost at vSLslope and vCp correlated to RCP (0.62 and 0.69) and V̇O2max (0.70 and 0.79). Conclusion: SL and SR exhibited a distinctive pattern for the V̇O2 response as swimming velocity increased. Furthermore, the influence of SL on GET, RCP, and V̇O2max suggests that SLslope serves as the metabolic reference of heavy exercise intensity, beyond which the stroke profile defines an exercise zone with high cost, which is recommended for an anaerobic threshold and aerobic power training. In turn, the observed difference between V̇O2 at SRslope and GET suggests that the range of velocities between SL and SR slopes ensures an economical pace, which might be recommended to develop long-term endurance. The results also highlighted that the swimming intensity paced at Cp would impose a high anaerobic demand, as it is located above the maximal aerobic velocity. Therefore, SLslope and SRslope are suitable indexes of submaximal to maximal aerobic paces, while Cp's meaning still requires further evidence.

Acute Ingestion of a Ketone Monoester without Co-ingestion of Carbohydrate Improves Running Economy in Male Endurance Runners.

Acute ingestion of a ketone monoester, with and without co-ingestion of carbohydrate, was investigated for effects on running economy (RE), time to exhaustion (TTE), and other related indices of endurance running performance. Using a three condition, placebo-controlled, randomized crossover design, 11 male middle- and long-distance runners ran at five submaximal speeds (10-14 km·h -1 ) on a motorized treadmill for 8 min each, immediately followed by a ramp test to volitional exhaustion. Participants consumed either a 10% carbohydrate solution (CHO), a 10% carbohydrate solution with 750 mg·kg -1 body mass of an ( R )-3-hydroxybutyl ( R )-3-hydroxybutyrate ketone monoester (CHO + KE), or 750 mg·kg -1 body mass of the ketone monoester in flavored water (KE) before (two-thirds of the dose) and during (one-third of the dose) exercise. β-hydroxybutyrate concentration averaged 1.8 ± 0.3 and 2.1 ± 0.3 mM during exercise in CHO + KE and KE, respectively. RE was lower at each submaximal running speed (effect size = 0.48-0.98) by an average of 4.1% in KE compared with CHO, but not between CHO + KE and CHO. TTE did not differ between CHO (369 ± 116 s), CHO + KE (342 ± 99 s), or KE (333 ± 106 s) ( P = 0.093). Acute ingestion of a ketone monoester without carbohydrate, but not when coingested with carbohydrate, improved RE in middle- and long-distance runners at a range of submaximal running speeds and did not alter TTE in a short-duration ramp test to volitional exhaustion. Further investigation is required to examine if these differences translate into positive performance outcomes over longer durations of exercise.

Whole-body cooling effectiveness of cold intravenous saline following exercise hyperthermia: a randomized trial

IntroductionIn some athletic, occupational, military and emergency settings, cold intravenous (IV) fluids are used to facilitate whole-body cooling in an effort to treat heat illness. This treatment has anecdotal support, but currently lacks evidence supporting it as a whole-body cooling modality. Other modalities may offer superior cooling rates, and thus, patient outcomes following treatment. We sought to evaluate cooling rates of cold-IV normal saline immediately following exercise-induced hyperthermia. MethodsEight healthy participants (3 females; 25 ± 2y; 72.9 ± 10.9 kg) completed 2 trials in random order. Prior to exercise, participants provided a small urine sample to confirm hydration status via urine specific gravity. Wet bulb globe temperature (WBGT) was assessed throughout trials. In both trials, participants exercised outdoors until rectal temperature (Tre) reached ∼38.9 °C, or volitional exhaustion, and then were cooled. In cooling, participants received either cold-IV (∼5 °C 0.9% NaCl fluids) or no treatment (sat in the shade; passive). Throughout exercise and treatment, Tre and heart rate (HR) were monitored. During exercise and every 10 min throughout cooling, participants were asked to assess thermal sensation. ResultsHydration status (P = .847) was not significantly different prior to exercise between trials. WBGT throughout was not different between trials (P = .426). Maximum Tre reached was not different between cold-IV (38.88 ± 0.30 °C) and passive cooling (38.76 ± 0.28 °C) trials (P = .184). Mean cooling rate for cold-IV (0.039 ± 0.005 °C·min−1) was significantly greater than for passive cooling (0.028 ± 0.005 °C·min−1; P = .002). Tre throughout cooling was not different between trials (P = .707), but did decrease throughout (P = .008), regardless of trial. HR was decreased over time (P < .001), but cold-IV and passive cooling were not different throughout HR recovery (P = .141). Thermal sensation decreased throughout cooling (P < .001), but was not different between trials (p = .278). ConclusionEmergency medical personnel should adopt treatment protocols that employ documented effective treatments for exertional heat stroke. In isolation, our data casts significant doubt for the use of cold-IV saline infusion for whole-body cooling of hyperthermic individuals.

Cardiopulmonary exercise testing of patients with metastatic castrate-resistant prostate cancer as screening for vigorous exercise medicine prescription.

80 Background: Exercise is recommended for patients with prostate cancer to manage treatment adverse effects, improve quality of life and potentially influence cancer-specific outcomes. Men with advanced prostate cancer and metastatic disease may be at increased risk of cardiac events due to their cancer treatment and comorbidities. The aim of this study was to assess the safety and efficacy of cardiopulmonary exercise testing (CPET) for assessing cardiorespiratory capacity and risk screening of patients with metastatic castrate-resistant prostate cancer (mCRPC) prior to engaging in a vigorous program of exercise medicine. Methods: Experimental design was a cross-sectional analysis of screening CPET’s from a Phase III Randomised Controlled Trial (INTERVAL-GAP4) within the clinical setting involving men with mCRPC. Testing incorporated medically supervised, symptom limited, CPET with electrocardiogram (ECG) performed on a cycle ergometer until volitional exhaustion or maximal oxygen uptake peak (V02.PEAK) attained. Outcome Measurements included safety (incidence and severity of adverse events), feasibility (completion of CPET) and efficacy (performance outcomes, screen-fails, and cardiac pathology). Descriptive statistics were calculated as mean and standard deviation. Results: 104 men (age 71.5 ± 8.4 years) with mCRPC completed a medically supervised CPET. Of these, 96 patients (92.3%) met the criterion for V02.PEAK attainment and were randomised to the INTERVAL-GAP4 trial, with 8 (7.7%) CPET screen-fails. Four positive cardiac abnormalities (3.8%) were observed, with these patients referred to a cardiologist for further assessment. Referred patients were all cleared to participate in vigorous exercise with no clinically significant cardiovascular disease or were determined to have newly diagnosed and subsequently controlled cardiovascular disease. Average V02.PEAK was 1.72 ± 0.51 L.min-1 absolute and 18.96 ± 5.30 mL.kg-1.min-1 relative which is in the 10-15th percentile for healthy men of this age. Maximal heart rate achieved was 141 ± 20 bpm at a maximal workload of 128 ± 40 W. There were no cardiac events or any other exercise-related adverse events during the testing. Conclusions: Maximal CPET is safe for men with advanced prostate cancer. CPET with ECG is also an effective cardiac stress screening tool prior to engaging in a vigorous exercise medicine program to detect underlying cardiovascular health issues. Further, results from CPET can be used to inform appropriate exercise prescription individualised to the patient. Clinical trial information: NCT02730338 .

The Impact of Acute Mild Normobaric Hypoxia and a Single Bout of Exercise to Volitional Exhaustion on Cognitive Performance in Endurance and Strength-Trained Athletes: The role of BDNF, EP-1, Catecholamines and Lactate.

The aim of the study was to examine whether a single bout of exercise to volitional exhaustion, performed under moderate normobaric hypoxia (H), would affect psychomotor performance (PP) in differently trained athletes. For this purpose, ten strength-trained (S) athletes, ten endurance-trained (E) athletes and ten healthy men leading a sedentary lifestyle as a control (C) group performed voluntarily two graded exercise tests until volitional exhaustion (EVE) under normoxia (N) and H (FiO2 = 14.7%). We measured the peripheral level of the brain derived neurotrophic factor (BDNF), choice reaction time (CRT) and the number of correct reactions (NCR) as indices of PP. Psychomotor tests were performed at rest, immediately after the EVE and 3 minutes after the EVE. Venous blood samples were collected at rest, immediately after cessation of each EVE, and 1 h after each EVE. The results showed that the EVE significantly (p < 0.05) impaired CRT under N and H, and NCR under H only in the E group. The higher WRmax in the E compared to the S and C groups was associated with a significant (p < 0.005) increase in adrenaline (A) and noradrenaline (NA). There were no significant differences between conditions (N vs. H) in the BDNF at rest and after exercise. The EVE impaired cognitive function only in the E group; higher involvement of the sympathetic nervous system, A and NA may also play a role in this phenomenon. Therefore, it can be concluded that exposure to H did not have a negative impact on CRT or NCR. Moreover, BDNF did not improve cognitive function.

Effect of Ischemic Preconditioning (IPC) on Recovery of Exercise Performance Following a Bout of Exercise to Volitional Exhaustion

The purpose of the present study was to investigate the effect of ischemic preconditioning (IPC) on the recovery of exercise performance following maximal, incremental exercise. A total of 13 healthy males volunteered to participate, undertaking three experimental trials involving a constant work-rate bout of severe intensity exercise undertaken to the limit of tolerance that was preceded by a 40-min recovery period consequent to a maximal, incremental exercise test. During the recovery period, participants underwent IPC at 220 mmHg, sham IPC (SHAM; 20 mmHg), and passive rest (CON). Exercise tolerance time was higher following IPC as compared to SHAM and CON {199 ± 36 (CON) vs. 203 ± 35 (SHAM) vs. 219 ± 34 (IPC), p = 0.03}. This effect was accompanied by a tendency toward an augmented increase in blood lactate from rest to exercise in IPC compared to SHAM and CON (p = 0.08). There was no effect of IPC on oxygen uptake kinetics or muscle oxygenation as indicated via near-infrared spectroscopy. IPC may therefore have the capacity to augment recovery from prior maximal exercise, but this does not appear to be due to enhancements to oxygen uptake kinetics or muscle oxygenation.

#5045 CARDIORESPIRATORY FITNESS IN KIDNEY TRANSPLANT RECIPIENTS: A CASE-CONTROL STUDY AND INITIAL REVIEW OF THE EFFECTS OF A HOME-BASED EXERCISE PROGRAMME

Abstract Background and Aims Kidney transplant recipients (KTRs) have an increased burden of cardiovascular disease (CVD) due to clustering of traditional and non-traditional risk factors. Poor cardiorespiratory fitness (CRF) is linked to higher levels of morbidity and mortality. Cardiorespiratory fitness is a significant predictor of 7-year risk of mortality, with each 1 ml/kg/min increase in VO2 associated with a 1% decrease in risk of mortality.[1] Although KTRs have higher CRF than patients with kidney failure, performance compared to the general population has not been quantified. Neither has the link between CRF and physical function. We assessed differences in CRF between KTRs and healthy volunteers in a case-control study. We then explored relationships between CRF and physical function and possible effects of a 12-week structured home-based exercise programme in KTRs. Method Case-control: 20 KTRs (10 male; age 61.2 ±8.1 years; body mass 84.1 ±19.9 kg) and 20 healthy volunteers (10 male; age 61.9 ±7.7 years; body mass 76.7 ±18.1 kg) completed a continuous ramp cardiopulmonary exercise test (CPET) to volitional exhaustion on a cycle ergometer. CPET variables were compared between groups using independent samples t-tests. Thirteen KTRs (6 male; age 47.8 ±15.9 years; eGFR 64.6 ±19.1 ml/min/1.73 m2), to date, have completed a 12-week structured, combined aerobic and resistance, home-based exercise programme as part of a pilot randomised controlled trial.[2] Bivariate correlations were used to explore the association between cardiorespiratory fitness and physical function measures (sit-to-stand 60 [STS60], timed up and go [TUAG], gait speed [GS] and handgrip strength [HGS]). Paired samples t-tests were used to compare pre- and post-intervention variables. Results Case-control: Cardiorespiratory fitness (VO2 peak) was lower in KTRs (18.4±5.2 mL/kg/min) than in healthy volunteers (24.3 ±5.9 mL/kg/min), a difference of 5.9 mL/kg/min (95% CI, 2.4-9.5), t(38) = 3.35, p &amp;lt;.001. Peak heart rate achieved was higher in healthy volunteers than in KTRs (154 v 136 bpm; p = .009). Maximum power achieved was higher in healthy volunteers but did not reach significance (147 v 116 W; p = .052). There was a positive correlation between STS60 and VO2 peak (r = .652, p = .016) and between GS and VO2 peak (r = .583, p = .037). There was a negative correlation between TUAG and VO2 peak (r = .-.664, p = .013) and no association between HGS and VO2 peak. There was an increase in VO2 peak after the 12-week exercise programme (19.4±4.5 mL/kg/min to 20.4±5.0 mL/kg/min, p = .018). Maximum power achieved did not change post-intervention (118 v 121 W; p = .423). STS60 was the only physical function test to improve post-intervention (24 v 27; p = .010). Conclusion Cardiorespiratory fitness in KTRs is significantly impaired compared to healthy control subjects. In KTRs, aerobic fitness assessed with VO2 peak correlated with field tests assessing physical function. Initial findings suggest that CRF may improve following a structured, home-based programme of exercise, but these data need confirming in larger studies and will be assessed in the final analysis of this pilot randomised trial.

Humid Heat Equally Impairs Maximal Exercise Performance in Elite Para-Athletes and Able-Bodied Athletes.

This study aimed to compare the impact of hot-humid environmental conditions on performance outcomes, thermoregulatory responses, and thermal perception during exercise between elite para- and able-bodied (AB) athletes. Twenty elite para-athletes (para-cycling and wheelchair tennis) and 20 elite AB athletes (road cycling, mountain biking, beach volleyball) performed an incremental exercise test in a temperate environment (mean ± SD, 15.2°C ± 1.2°C; relative humidity, 54% ± 7%) and a hot-humid environment (31.9°C ± 1.6°C, 72% ± 5%). Exercise tests started with a 20-min warm-up at 70% of maximal heart rate, after which power output increased by 5% every 3 min until volitional exhaustion. Time to exhaustion was shorter in hot-humid versus temperate conditions, with equal performance loss for para- and AB athletes (median (interquartile range), 26% (20%-31%) vs 27% (19%-32%); P = 0.80). AB athletes demonstrated larger exercise-induced increases in gastrointestinal temperature (T gi ) in hot-humid versus temperate conditions (2.2 ± 0.7 vs 1.7 ± 0.5, P < 0.001), whereas T gi responses in para-athletes were similar between conditions (1.3 ± 0.6 vs 1.3 ± 0.4, P = 0.74). Para- and AB athletes showed similar elevations in peak skin temperature ( P = 0.94), heart rate ( P = 0.67), and thermal sensation score ( P = 0.64) in hot-humid versus temperate conditions. Elite para-athletes and AB athletes demonstrated similar performance decrements during exercise in hot-humid versus temperate conditions, whereas T gi elevations were markedly lower in para-athletes. We observed large interindividual variation within both groups, suggesting that in both para- and AB athletes, personalized heat mitigation plans should be developed based on individual thermal testing.

Biomechanical adaptations during exhaustive runs at 90 to 120% of peak aerobic speed

The aim of this study was to examine how running biomechanics (spatiotemporal and kinetic variables) adapt with exhaustion during treadmill runs at 90, 100, 110, and 120% of the peak aerobic speed (PS) of a maximal incremental aerobic test. Thirteen male runners performed a maximal incremental aerobic test on an instrumented treadmill to determine their PS. Biomechanical variables were evaluated at the start, mid, and end of each run until volitional exhaustion. The change of running biomechanics with fatigue was similar among the four tested speeds. Duty factor and contact and propulsion times increased with exhaustion (P ≤ 0.004; F ≥ 10.32) while flight time decreased (P = 0.02; F = 6.67) and stride frequency stayed unchanged (P = 0.97; F = 0.00). A decrease in vertical and propulsive peak forces were obtained with exhaustion (P ≤ 0.002; F ≥ 11.52). There was no change in the impact peak with exhaustion (P = 0.41; F = 1.05). For runners showing impact peaks, the number of impact peaks increased (P ≤ 0.04; {upchi }^{2} ≥ 6.40) together with the vertical loading rate (P = 0.005; F = 9.61). No changes in total, external, and internal positive mechanical work was reported with exhaustion (P ≥ 0.12; F ≤ 2.32). Results suggest a tendency towards a “smoother” vertical and horizontal running pattern with exhaustion. A smoother running pattern refers to the development of protective adjustments, leading to a reduction of the load applied to the musculoskeletal system at each running step. This transition seemed continuous between the start and end of the running trials and could be adopted by the runners to decrease the muscle force level during the propulsion phase. Despite these changes with exhaustion, there were no changes in either gesture speed (no alteration of stride frequency) or positive mechanical work, advocating that runners unconsciously organize themselves to maintain a constant whole-body mechanical work output.

Redirected Attention and Impaired Recognition Memory during Exhaustive Cycling Has Implications for Information Processing Models of Effort-Regulation.

Twenty male participants performed two laboratory ramped cycling tests beginning at 50 W and increasing by 0.25 W/s until volitional exhaustion. Ratings of perceived exertion, heart rate and respiratory gas exchange measures were recorded during the first test. During the second test, participants listened to a list of spoken words presented through headphones at a rate of one word every 4 s. Afterwards, their recognition memory for the word pool was measured. Recognition memory performance was found to have strong negative correlations with perceived exertion (p < 0.0001), percentage of peak power output (p < 0.0001), percentage of heart rate reserve (p < 0.0001), and percentage of peak oxygen uptake (p < 0.0001). The results show that, as the physiological and psychophysiological stress of cycling intensified, recognition memory performance deteriorated. This might be due to impairment of memory encoding of the spoken words as they were presented, or because of a diversion of attention away from the headphones, perhaps towards internal physiological sensations as interoceptive sources of attentional load increase with exercise intensity. Information processing models of pacing and performance need to recognise that an athlete's capacity to attend to and process external information is not constant, but changes with exercise intensity.

Metabolic Signatures of Performance in Elite World Tour Professional Male Cyclists.

Metabolomics studies of recreational and elite athletes have been so far limited to venipuncture-dependent blood sample collection in the setting of controlled training and medical facilities. However, limited to no information is currently available to determineif findings in laboratory settings are translatable to a real-world scenario in elite competitions.The goal of this study was to define molecular signatures of exertion under controlled exercise conditions and use these signatures as a framework for assessing cycling performance in a World Tour competition. To characterize molecular profiles of exertion in elite athletes during cycling, we performed metabolomics analyses on blood isolated from 28 international-level, elite, World Tour professional male athletes from a Union Cycliste Internationale World Team taken before and after a graded exercise test to volitional exhaustion and before and after a long aerobic training session. Moreover, established signatures were then used to characterize the metabolic physiology of five of these cyclists who were selected to represent the same Union Cycliste Internationale World Team during a seven-stage elite World Tour race. Using dried blood spot collection to circumvent logistical hurdles associated with field sampling, these studies defined metabolite signatures and fold change ranges of anaerobic or aerobic exertion in elite cyclists, respectively. Blood profiles of lactate, carboxylic acids, fatty acids, and acylcarnitines differed between exercise modes. The graded exercise test elicited significant two- to three-fold accumulations in lactate and succinate, in addition to significant elevations in free fatty acids and acylcarnitines. Conversely, the long aerobic training session elicited a larger magnitude of increase in fatty acids and acylcarnitines without appreciable increases in lactate or succinate. Comparable signatures were revealed after sprinting and climbing stages, respectively, in a World Tour race. In addition, signatures of elevated fatty acid oxidation capacity correlated with competitive performance. Collectively, these studies provide a unique view of alterations in the blood metabolome of elite athletes during competition and at the peak of their performance capabilities. Furthermore, they demonstrate the utility of dried blood sampling for omics analysis, thereby enabling molecular monitoring of athletic performance in the field during training and competition.

Impact of sex on the cerebrovascular response to incremental aerobic exercise in moderately trained endurance athletes.

The cerebrovascular response to incremental aerobic exercise is comparable between males and females. Whether this response can be found in moderately trained athletes remains unknown. We aimed to examine the effect of sex on the cerebrovascular response to incremental aerobic exercise until volitional exhaustion in this population. Twenty-two moderately trained athletes (11 M/11 F; age: 25 ± 5 vs. 26 ± 6 yr, P = 0.6478; peak oxygen consumption: 55.8 ± 5.2 vs. 48.3 ± 4 mL/kg/min; P = 0.0011; training volume: 532 ± 173 vs. 466 ± 151 min/wk, P = 0.3554) performed a maximal ergocycle exercise test. Systemic and cerebrovascular hemodynamics were measured. At rest, middle cerebral artery mean blood velocity (MCAvmean; 64.1 ± 12.7 vs. 72.2 ± 15.3 cm·s-1; P = 0.2713) was not different between groups, whereas partial pressure of end-tidal carbon dioxide ([Formula: see text], 42 ± 3 vs. 37 ± 2 mmHg, P = 0.0002) was higher in males. During the MCAvmean ascending phase, changes in MCAvmean (intensity: P < 0.0001, sex: P = 0.3184, interaction: P = 0.9567) were not different between groups. Changes in cardiac output ([Formula: see text]) (intensity: P < 0.0001, sex: P < 0.0001, interaction: P < 0.0001) and [Formula: see text] (intensity: P < 0.0001, sex: P < 0.0001, interaction: P < 0.0001) were higher in males. During the MCAvmean descending phase, changes in MCAvmean (intensity: P < 0.0001, sex: P = 0.5522, interaction: P = 0.4828) and [Formula: see text] (intensity: P = 0.0550, sex: P = 0.0003, interaction: P = 0.2715) were not different between groups. Changes in [Formula: see text] (intensity P < 0.0001, sex: P < 0.0001, interaction: P = 0.0280) were higher in males. These results suggest the MCAvmean response during exercise is comparable between moderately trained males and females notwithstanding differences in the response of key cerebral blood flow determinants.NEW & NOTEWORTHY The results of this study suggest the cerebrovascular response between moderately endurance-trained males and females is comparable in spite of a higher arterial carbon dioxide and cardiac output in males compared with females during incremental aerobic exercise until volitional exhaustion. This could help in providing a better understanding of the key differences in cerebral blood flow regulation between males and females during aerobic exercise.

A Comparison of Basic Training Variables in the Standard and Cambered Bar Bench Press Performed to Volitional Exhaustion.

The objective of this study was to compare the impact of cambered and standard barbells used during the bench press exercise on the number of performed repetitions and mean velocity during a bench press training session that included 5 sets performed to volitional failure at 70% of one-repetition maximum (1RM) (for each barbell type). An additional objective was to determine whether there would be any difference in neuromuscular fatigue assessed by peak velocity changes during bench press throws performed 1 and 24 hours after the cessation of each session. The research participants included 12 healthy resistance-trained men. Participants performed 5 sets of the bench press exercise to volitional failure against 70% of 1RM with the cambered or standard barbell. The Friedman's test showed an overall trend of a significant decrease in the mean velocity (p < 0.001) and a number of performed repetitions (p < 0.001) from the first to the fifth set (p < 0.006 and p < 0.02, respectively for all) under both conditions, yet neither bar showed significant differences between the corresponding sets. Two-way ANOVA indicated a significant main effect of time (p < 0.001) for peak velocity during the bench press throw. The post-hoc comparisons showed significantly lower peak velocity during the bench press throw one hour after the bench press compared to pre (p = 0.003) and 24-hour post intervention (p = 0.007). Both barbells caused a similar decrease in peak barbell velocity during the bench press throw performed one hour after the bench press training session, with values returning to baseline 24 hours later. This indicates that bench press workouts with either a standard or a cambered barbell present the same training demands.

Local heating and cooling with isometric exercise training as a strategy to improve size and performance

The purpose of this study was to explore the effects of local heating and cooling with isometric exercise training of upper arm and forearm. College-aged (n=12; 21±1 y) volunteers performed 4-wk isometric exercise training of the non-dominant arm (upper arm, isometric bicep curl; forearm, handgrip), while the dominant arm served as the control. Training was performed 3x/wk and consisted of 1 set of isometric handgrip and bicep curl until volitional exhaustion at 60% pre-training MVC for the forearm (handgrip) and 1RM for the upper arm (bicep curl). Randomized ordering of heating (40°C; 15 min) and cooling (12°C; 15 min) preceded each training session. Indirect assessment of muscle size (fat-free cross-sectional area [FFCSA]) was made before and after the training period via skin fold and limb circumference measures. Biceps 1RM increased significantly (p &lt; 0.05) after the intervention in both conditions (trained: +6%; control: +7%), whereas only the control arm increased time to fatigue (+40%; p &lt; 0.05). FFSCA of the upper arm remained unchanged (p&gt;0.05) in both conditions. An effect of time was noted for forearm MVC (+8%; p &lt; 0.05), while both groups increased (p &lt; 0.05) time to fatigue (trained: +82%; control: +64%). A trend toward an effect of time was also noted for FFCSA of the forearm (+3%; p &lt;.10). While the intervention employed here led to many notable adaptations, the thermal stress did not appear to exert a clear benefit. Coupled with the practicality and feasibility, improving size and performance in such a short time frame has therapeutic and ergogenic aid implications.

Psychomotor Performance after 30 h of Sleep Deprivation Combined with Exercise.

Sleep deprivation (SD) usually impairs psychomotor performance, but most experiments are usually focused on sedentary conditions. The purpose of this study was to evaluate the influence of 30 h of complete SD combined with prolonged, moderate exercise (SDE) on human psychomotor performance. Eleven endurance-trained men accustomed to overnight exertion were tested twice: in well-slept and non-fatigued conditions (Control) and immediately after 30 h of SDE. They performed a multiple-choice reaction time test (MCRT) at rest and during each workload of the graded exercise test to volitional exhaustion. At rest, the MCRT was shorter after SDE than in the Control (300 ± 13 ms vs. 339 ± 11 ms, respectively, p < 0.05). During graded exercise, there were no significant differences in MCRT between groups, but the fastest reaction was observed at lower workloads after SDE (158 ± 7 W vs. 187 ± 11 W in Control, p < 0.05). The total number of missed reactions tended to be higher after SDE (8.4 ± 0.7 vs. 6.3 ± 0.8 in Control, p = 0.06). In conclusion, SDE is different from SD alone; however, well-trained men, accustomed to overnight exertion can maintain psychomotor abilities independently of the extent of central fatigue. Exercise can be used to enhance psychomotor performance in sleep-deprived subjects in whom special caution is required in order to avoid overload.

Perception of exercise-induced dyspnea after experimentally induced breathing discomfort.

The perception of dyspnea is influenced by both physiological and psychological factors. We sought to determine whether exertional dyspnea perception could be experimentally manipulated through prior exposure to heightened dyspnea while exercising. We hypothesized that dyspnea perception during exercise would be lower following an induced dyspnea task (IDT). Sixteen healthy participants (eight females, eight males) completed two days of exercise testing. Day 1 involved an incremental cycle exercise test starting at 40 W for females and 60 W for males, increasing by 20 W each minute until volitional exhaustion. Following the maximal exercise test on Day 1, participants completed IDT, involving 5 min of exercise at 70% of peak work rate with 500 mL dead space and external resistance (i.e., 6.8 ± 2.3 cm·H2O·s-1·L-1 inspiration, 3.8 ± 0.7 cm·H2O·s-1·L-1 expiration). Day 2 consisted of an incremental exercise test identical to Day 1. At maximal exercise, there were no differences in oxygen uptake (V̇O2; 44.7 ± 7.7vs. 46.5 ± 6.3 mL·kg-1·min-1), minute ventilation (120 ± 35vs. 127 ± 38 L·min-1), dyspnea (6.5 [4, 8.5] vs. 6 [4.25, 8.75]), or leg discomfort (6 [5, 8.75] vs. 7 [5, 9]) between days (all p > 0.05). At 60%-80% of peak V̇O2 (V̇O2peak), dyspnea was significantly lower on Day 2 (-0.75 [-1.375, 0] for 60% and -0.5 [0, -2] for 80%, p < 0.05) despite no differences in relevant physiological variables. The onset of perceived dyspnea occurred at a significantly higher exercise intensity on Day 2 than on Day 1 (42% ± 19%vs. 51% ± 17% V̇O2peak, respectively; p < 0.05). Except for 40% V̇O2peak (p = 0.05), RPE-L was not different at any intensities nor was the onset of perceived leg discomfort different between days (38% ± 14%vs. 43% ± 10% V̇O2peak, respectively; p = 0.10). Exposure to heightened dyspnea alters exercise-induced dyspnea perception during subsequent submaximal exercise bouts.

The polyphenol epigallocatechin gallate lowers circulating catecholamine concentrations and alters lipid metabolism during graded exercise in man: a randomized cross-over study

PurposePhysical exercise is shown to mitigate catecholamine metabolites; however, it is unknown if exercise-induced increases in sympatho-adrenal activity or catecholamine metabolites are influenced by ingestion of specific catechins found within green tea. This study explored the impact of epigallocatechin gallate (EGCG) ingestion on catecholamine metabolism during graded cycle exercise in humans.MethodsEight males (22.4 ± 3.3 years, BMI:25.7 ± 2.4 kg.m2) performed a randomised, placebo-controlled, single-blind, cross-over trial after consumption (1450 mg) of either EGCG or placebo (PLAC) and performed graded cycling to volitional exhaustion. Venous bloods were taken at rest, 2 h post-ingestion and after every 3-min stage. Blood variables were analysed for catecholamines, catecholamine metanephrines and metabolic variables at rest, 2 h post-ingestion (POST-ING), peak rate of lipid oxidation (FATpeak), lactate threshold (LT) and peak rate of oxygen consumption (VO2peak). Data were analysed using SPSS (Version 26).ResultsResting catecholamine and metanephrines were similar between trials. Plasma adrenaline (AD) was lower in ECGC treatment group between trials at FATpeak (P < 0.05), LT (P < 0.001) and VO2peak (P < 0.01). Noradrenaline (NA) was lower under EGCG at POST (P < 0.05), FATpeak (P < 0.05), LT (P < 0.01) and VO2peak (P < 0.05) compared to PLAC. Metanephrines, glucose and lactate increased similarly with exercise intensity in both trials. Lipid oxidation rate was 32% lower in EGCG at FATpeak (EGCG 0.33 ± 0.14 vs. PLAC 0.49 ± 0.11 g.min−1, P < 0.05). Cycle time to exhaustion was similar (NS).ConclusionAcute EGCG supplementation reduced circulating catecholamines but not; metanephrine, glucose or lactates, response to graded exercise. Lower circulating catecholamines may explain a lower lipid oxidation rate.

Sequencing patterns of ventilatory indices in less trained adults.

Submaximal ventilatory indices, i.e., point of optimal ventilatory efficiency (POE) and anaerobic threshold (AT), are valuable indicators to assess the metabolic and ventilatory response during cardiopulmonary exercise testing (CPET). The order in which the ventilatory indices occur (ventilatory indices sequencing pattern, VISP), may yield additional information for the interpretation of CPET results and for exercise intensity prescription. Therefore, we determined whether different VISP groups concerning POE and AT exist. Additionally, we analysed fat metabolism via the exercise intensity eliciting the highest fat oxidation rate (Fatmax) as a possible explanation for differences between VISP groups. 761 less trained adults (41-68 years) completed an incremental exercise test on a cycle ergometer until volitional exhaustion. The ventilatory indices were determined using automatic and visual detection methods, and Fatmax was determined using indirect calorimetry. Our study identified two VISP groups with a lower work rate at POE compared to AT in VISPPOE < AT but not in group VISPPOE = AT. Therefore, training prescription based on POE rather than AT would result in different exercise intensity recommendations in 66% of the study participants and consequently in unintended physiological adaptions. VISPPOE < AT participants were not different to VISPPOE = AT participants concerning VO2peak and Fatmax. However, participants exhibiting a difference in work rate (VISPPOE < AT) were characterized by a higher aerobic capacity at submaximal work rate compared to VISPPOE = AT. Thus, analysing VISP may help to gain new insights into the complex ventilatory and metabolic response to exercise. But a methodological framework still must be established.