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Background: Spiroergometry is important for modern performance diagnostics, and reference values have been evaluated for bicycle and treadmill ergometers. The aim of this study is to assess the comparability of bicycle and hand-crank spiroergometry and its associated parameters, as hand-crank spiroergometry can be used during rehabilitation in patients with definitive or temporally impairment of the lower extremity. Methods: Thirty-seven healthy volunteers completed 2 exhausting performance diagnostics on hand-crank and bicycle spiroergometry. Participants' anthropometric characteristics, maximum power, multiple exertion criteria, maximum aerobic capacity, and maximum heart rate were detected, and ventilatory and metabolic thresholds were determined. Results: The maximum power, maximum heart rate, maximum aerobic capacity, and ventilatory thresholds were significant higher on the bicycle ergometer (P <.001). The metabolic thresholds occurred on higher lactate values on the hand-crank ergometer. Equations for calculating maximum aerobic capacity from the maximum power measured in either hand-crank or bicycle ergometer could be found through regression analysis. Conclusions: Although there are problems in interpreting results of different ergometries due to severe physiology differences, the equations can be used for patients who are temporally unable to complete the established ergometry due to a deficit in the lower extremity. This could improve training recommendations for patients and para-athletes in particular. [ABSTRACT FROM AUTHOR]

This study aimed to determine whether caffeine gum influenced perceptual-cognitive and physical performance during the extra-time period of simulated soccer match-play. Semiprofessional male soccer players (n = 12, age: 22 ± 3 years, stature: 1.78 ± 0.06 m, mass: 75 ± 9 kg) performed 120-min soccer-specific exercise on two occasions. In a triple-blind, randomized, crossover design, players chewed caffeinated (200 mg; caffeine) or control (0 mg; placebo) gum for 5 min following 90 min of soccer-specific exercise. Perceptual-cognitive skills (i.e., passing accuracy, reaction time, composure, and adaptability) were assessed using a soccer-specific virtual reality simulator, collected pre- and posttrial. Neuromuscular performance (reactive-strength index, vertical jump height, absolute and relative peak power output, and negative vertical displacement) and sprint performance (15 and 30 m) were measured at pretrial, half-time, 90 min, and posttrial. Caffeine gum attenuated declines in reaction time (pre: 90.8 ± 0.8 AU to post: 90.7 ± 0.8 AU) by a further 4.2% than placebo (pre: 92.1 ± 0.8 AU to post: 88.2 ± 0.8 AU; p <.01). Caffeine gum reduced composure by 4.7% (pre: 69.1 ± 0.8 AU to post: 65.9 ± 0.8 AU) versus placebo (pre: 68.8 ± 0.8 AU to post: 68.3 ± 0.8 AU; p <.01). Caffeine gum did not influence any other variables (p >.05). Where caffeine gum is consumed by players prior to extra-time, reaction time increases but composure may be compromised, and neuromuscular and sprint performance remain unchanged. Future work should assess caffeine gum mixes with substances like L-theanine that promote a relaxed state under stressful conditions. [ABSTRACT FROM AUTHOR]

This study investigated the test–retest reliability of running economy (RE) and metabolic and cardiorespiratory parameters related to endurance running performance using a multistage incremental treadmill test. On two occasions separated by 21–28 days, 12 male middle- and long-distance runners ran at 10, 11, 12, 13, and 14 km/hr for 8 min each stage, immediately followed by a ramp test to volitional exhaustion. Carbohydrate (10% maltodextrin solution) was consumed before and during the test to provide ∼1 g/min of exercise. RE, minute ventilation ( V ˙ E), oxygen consumption ( V ˙ O 2 ), carbon dioxide production ( V ˙ CO 2 ), respiratory exchange ratio (RER), heart rate (HR), ratings of perceived exertion (RPE), and blood glucose and lactate concentrations were recorded for each stage and at volitional exhaustion. Time-to-exhaustion (TTE) and peak oxygen consumption ( V ˙ O 2 peak) during the ramp test were also recorded. Absolute reliability, calculated as the coefficient of variation (CV) between repeated measures, ranged from 2.3% to 3.1% for RE, whereas relative reliability, calculated as the intraclass correlation coefficient (ICC), ranged from.42 to.79. V ˙ E , V ˙ O 2 , V ˙ O 2 peak , V ˙ CO 2 , RER, and HR had a CV of 1.1%–4.3% across all stages. TTE and RPE had a CV of 7.2% and 2.3%–10.8%, respectively, while glucose and lactate had a CV of 4.0%–17.8%. All other parameters, except for blood glucose, were demonstrated to have good-to-excellent relative reliability assessed by ICC. Measures of RE, V ˙ O 2 peak , and TTE were reliable during this two-phase multistage incremental treadmill test in a cohort of trained and highly trained male middle- and long-distance runners. [ABSTRACT FROM AUTHOR]

Carbohydrate (CHO) supplementation during endurance exercise can improve performance. However, it is unclear whether low glycemic index (GI) CHO leads to differential ergogenic and metabolic effects compared with a standard high GI CHO. This study investigated the ergogenic and metabolic effects of CHO supplementation with distinct GIs, namely, (a) trehalose (30 g/hr), (b) isomaltulose (30 g/hr), (c) maltodextrin (60 g/hr), and (d) placebo (water). In this double-blind, crossover, counterbalanced, placebo-controlled study, 13 male cyclists cycled a total of 100 min at varied exercise intensity (i.e., 10-min stages at 1.5, 2.0, and 2.5 W/kg; repeated three times plus two 5-min stages at 1.0 W/kg before and after the protocol), followed by a 20-min time trial on four separated occasions. Blood glucose and lactate (every 20 min), heart rate, and ratings of perceived exertion were collected throughout, and muscle biopsies were taken before and immediately after exercise. The results showed that trehalose improved time-trial performance compared with placebo (total work done 302 ± 39 vs. 287 ± 48 kJ; p =.01), with no other differences between sessions (all p ≥.07). Throughout the 100-min protocol, blood glucose was higher with maltodextrin compared with the other supplements at all time points (all p <.05). Heart rate, ratings of perceived exertion, muscle glycogen content, blood glucose, and lactate were not different between conditions when considering the 20-min time trial (all p >.05). Trehalose supplementation throughout endurance exercise improved cycling performance and appears to be an appropriate CHO source for exercise tasks up to 2 hr. No ergogenic superiority between the different types of CHO was established. [ABSTRACT FROM AUTHOR]

Purpose: To develop and evaluate a theory on the frequent observation that cyclists prefer cadences (RPMs) higher than those considered most economical at submaximal exercise intensities via modeling and simulation of its mathematical description. Methods: The theory combines the parabolic power-to-velocity (v) relationship, where v is defined by crank length, RPM-dependent ankle velocity, and gear ratio, RPM effects on the maximal lactate steady state (MLSS), and lactate-dependent carbohydrate oxidation (CHO). It was tested against recent experimental results of 12 healthy male recreational cyclists determining the v-dependent peak oxygen uptake (VO2PEAKv), MLSS (MLSSv), corresponding power output (PMLSSv), oxygen uptake at PMLSSv (VO2MLSSv), and CHOMLSSv-management at 100 versus 50 per minute, respectively. Maximum RPM (RPMMAX) attained at minimized pedal torque was measured. RPM-specific maximum sprint power output (PMAXv) was estimated at RPMs of 100 and 50, respectively. Results: Modeling identified that MLSSv and PMLSSv related to PMAXv (IPMLSSv) promote CHO and that VO2MLSSv related to VO2PEAKv inhibits CHO. It shows that cycling at higher RPM reduces IPMLSSv. It suggests that high cycling RPMs minimize differences in the reliance on CHO at MLSSv between athletes with high versus low RPMMAX. Conclusions: The present theory-guided modeling approach is exclusively based on data routinely measured in high-performance testing. It implies a higher performance reserve above IPMLSSv at higher RPM. Cyclists may prefer high cycling RPMs because they appear to minimize differences in the reliance on CHO at MLSSv between athletes with high versus low RPMMAX. [ABSTRACT FROM AUTHOR]

Purpose: To assess (1) whether and how a higher maximal lactate steady state (MLSS) at higher cycling cadence (RPM) comes along with higher absolute and/or fractional carbohydrate combustion (CHOMLSS), respectively, and (2) whether there is an interrelation between potential RPM-dependent MLSS effects and the maximally achievable RPM (RPMMAX). Methods: Twelve healthy males performed incremental load tests to determine peak power, peak oxygen uptake, and 30-minute MLSS tests at 50 and 100 per minute, respectively, to assess RPM-dependent MLSS, corresponding power output, CHOMLSS responses, and 6-second sprints to measure RPMMAX. Results: Peak power, peak carbon dioxide production, and power output at MLSS were lower (P =.000, ω2 = 0.922; P =.044, ω2 > 0.275; and P =.016, ω2 = 0.373) at 100 per minute than at 50 per minute. With 6.0 (1.5) versus 3.8 (1.2) mmol·L−1, MLSS was higher (P =.000, ω2 = 0.771) at 100 per minute than at 50 per minute. No corresponding RPM-dependent differences were found in oxygen uptake at MLSS, carbon dioxide production at MLSS, respiratory exchange ratio at MLSS, CHOMLSS, or fraction of oxygen uptake used for CHO at MLSS, respectively. There was no correlation between the RPM-dependent difference in MLSS and RPMMAX. Conclusions: The present study extends the previous finding of a consistently higher MLSS at higher RPM by indicating (1) that at fully established MLSS conditions, respiration and CHOMLSS management do not differ significantly between 100 per minute and 50 per minute, and (2) that linear correlation models did not identify linear interdependencies between RPM-dependent MLSS conditions and RPMMAX. [ABSTRACT FROM AUTHOR]

This study sought to investigate the effect of cold ambient temperature on subcutaneous abdominal adipose tissue (SCAAT) lipolysis and blood flow during steady-state endurance exercise in endurance-trained cyclists. Ten males (age: 23 ± 3 years; peak oxygen consumption: 60.60 ± 4.84 ml·kg−1·min−1; body fat: 18.4% ± 3.5%) participated in baseline lactate threshold (LT) and peak oxygen consumption testing, two familiarization trials, and two experimental trials. Experimental trials consisted of cycling in COLD (3 °C; 42% relative humidity) and neutral (NEU; 19 °C; 39% relative humidity) temperatures. Exercise consisted of 25 min cycling at 70% LT and 25 min at 90% LT. In situ SCAAT lipolysis and blood flow were measured via microdialysis. Heart rate, core temperature, carbohydrate and fat oxidation, blood glucose, and blood lactate were also measured. Heart rate, core temperature, oxygen consumption, and blood lactate increased with exercise but were not different between COLD and NEU. SCAAT blood flow did not change from rest to exercise or between COLD and NEU. Interstitial glycerol increased during exercise (p <.001) with no difference between COLD and NEU. Fat oxidation increased (p <.001) at the onset of exercise and remained elevated thereafter with no difference between COLD and NEU. Carbohydrate oxidation increased with increasing exercise intensity and was greater at 70% LT in COLD compared to NEU (p =.030). No differences were observed between conditions for any other variable. Cycling exercise increased SCAAT lipolysis but not blood flow. Ambient temperature did not alter SCAAT metabolism, SCAAT blood flow, or fat oxidation in well-trained cyclists, though cold exposure increased whole-body carbohydrate oxidation at lower exercise intensities. [ABSTRACT FROM AUTHOR]

Purpose: Fran is one of the most popular CrossFit benchmark workouts used to control CrossFitters' improvements. Detailed physiological characterization of Fran is needed for a more specific evaluation of CrossFitters' training performance improvements. The aim of the study was to analyze the oxygen uptake ( V ˙ O 2 ) kinetics and characterize the energy system contributions and the degree of postexercise fatigue of the unbroken Fran. Methods: Twenty trained CrossFitters performed Fran at maximal exertion. V ˙ O 2 and heart-rate kinetics were assessed at baseline and during and post-Fran. Blood lactate and glucose concentrations and muscular fatigue were measured at baseline and in the recovery period. Results: A marked increase in V ˙ O 2 kinetics was observed at the beginning of Fran, remaining elevated until the end (V ˙ O 2 peak : 49.2 [3.7] mL·kg−1·min−1, V ˙ O 2 amplitude: 35.8 [5.2] mL·kg−1·min−1, time delay: 4.7 [2.5] s and time constant: 23.7 [11.1] s; mean [SD]). Aerobic, anaerobic lactic, and alactic pathways accounted for 62% (4%), 26% (4%), and 12% (2%) of energy contribution. Reduction in muscle function in jumping ability (jump height: 8% [6%], peak force: 6% [4%], and maximum velocity: 4% [2%]) and plank prone test (46% [20%]) was observed in the recovery period. Conclusions: The Fran unbroken workout is a high-intensity effort associated with an elevated metabolic response. This pattern of energy response highlights the primary contribution of aerobic energy metabolism, even during short and very intense CrossFit workouts, and that recovery can take >24 hours due to cumulative fatigue. [ABSTRACT FROM AUTHOR]

Purpose: To investigate performance-determining variables of an on-snow sprint cross-country skiing competition and the evolvement in their relationship with performance as the competition progresses from the individual time trial (TT) to the final. Methods: Sixteen national-level male junior skiers (mean [SD] age, 18.6 [0.8] y; peak oxygen uptake [VO2peak], 67.6 [5.5] mL·min−1·kg−1) performed a simulated sprint competition (1.3 km) in the skating style, comprising a TT followed by 3 finals (quarterfinals, semifinals, and final) completed by all skiers. In addition, submaximal and incremental roller-ski treadmill tests, on-snow maximal speed tests, and strength/power tests were performed. Results: VO2peak and peak treadmill speed during incremental testing and relative heart rate, rating of perceived exertion, blood lactate concentrations, and gross efficiency during submaximal testing were all significantly correlated with performance in the TT and subsequent finals (mean [range] r values:.67 [.53–.86], all P <.05). Relative VO2peak and submaximal relative heart rate and blood lactate concentration were more strongly correlated with performance in the semifinals and final compared with the TT (r values:.74 [.60–.83] vs 0.55 [.51–.60], all P <.05). Maximal speed in uphill and flat terrain was significantly correlated with performance in the TT and subsequent finals (r values:.63 [.38–.70], all P <.05), while strength/power tests did not correlate significantly with sprint performance. Conclusions: VO2peak and high-speed abilities were the most important determinants of sprint cross-country skiing performance, with an increased importance of VO2peak as the competition format progressed toward the final. [ABSTRACT FROM AUTHOR]

Purpose: To compare the energetic contribution and pacing in 2000- and 1500-m maximal rowing-ergometer performances. Methods: On separate visits (>48 h apart, random order), 18 trained junior (16.7 [0.4] y) male rowers completed 3 trials: a 7 × 4-minute graded exercise test, a 2000-m time trial (TT2000), and a 1500-m TT (TT1500). Respiratory gases were continuously measured throughout each trial. The submaximal power-to-oxygen-consumption relationship from the graded exercise test was used to determine the accumulated oxygen deficit for each TT. Differences in mean power output (MPO), relative anaerobic contribution, percentage of peak oxygen uptake, pacing index, maximum heart rate, rating of perceived exertion, and blood lactate concentration were assessed using linear mixed modeling. Results: Compared to TT2000 (324 [24] W), MPO was 5.2% (3.3%) higher in TT1500 (341 [29 W]; P <.001, η p 2 =.70). There was a 4.9% (3.3%) increase (P <.001, η p 2 =.71) in anaerobic contribution from 17.3% (3.3%) (TT2000) to 22.2% (4.3%) (TT1500). Compared to TT1500, maximum heart rate, rating of perceived exertion, and blood lactate concentration were all greater (P <.05) in TT2000. The pacing index was not different between trials. Percentage increase in MPO from TT2000 to TT1500 was negatively associated with pacing variance in TT1500 (R2 =.269, P =.027). Conclusions: Maximal ergometer performance over 1500 m requires a significantly greater anaerobic contribution compared with 2000 m. Junior male athletes adopt a consistent pacing strategy across both distances. However, those who experienced greater percentage increases in MPO over the shorter test adopted a more even pacing strategy. To prepare for 1500-m performance, greater emphasis should be placed on developing capacity for work in the severe domain and completing race simulations with a more even pacing strategy. [ABSTRACT FROM AUTHOR]

Guarana (GUA) seed extract, containing caffeine (CAF) and additional bioactive compounds, may positively affect mental performance, but evidence regarding exercise is limited. This investigation assessed acute GUA ingestion compared with CAF on endurance performance. Eleven endurance-trained noncyclists and cyclists (V ˙ O 2 peak = 49.7 ± 5.9, 60.4 ± 4.6 ml·kg·min−1) completed a double-blind, crossover experiment after ingesting (a) 100 mg CAF, (b) 500 mg GUA (containing 130 mg CAF), or (c) placebo (P) prior to 60-min fixed cycling workload (FIX) + 15-min time trial. Oxygen uptake, heart rate, respiratory exchange ratio, blood glucose, and lactate were not different (p ≥.052) during FIX. A significant interaction (p =.042) for perceived exertion was observed at 50-min FIX with lower rating (p =.023) for GUA versus CAF but not compared with P. Work accumulated over 15-min time trial was greater (p =.038) for GUA versus P due to higher early (1–11 min) work outputs. Work performance favored (effect size = 0.18; 95% confidence interval [0.003, 0.355], p =.046) GUA (241.4 ± 39.9 kJ) versus P (232.1 ± 46.6 kJ), but CAF (232.3 ± 43.9) was not different from GUA (effect size = 0.19; 95% confidence interval [−0.022, 0.410], p =.079) or P. Postexercise strength loss was not attenuated with GUA (−5.6 ± 8.5%) or CAF (−8.3 ± 9.4%) versus P (−10.3 ± 5.1%). Acute GUA ingestion improved work performance relative to P, but effects were trivial to small and unrelated to altered substrate oxidation or muscular strength. Ergogenicity may involve central mechanisms reducing perceived effort with GUA (containing 130 mg caffeine). Due to issues related to identical matching of dosage, whether GUA confers additional benefits beyond its CAF content cannot be determined at present. [ABSTRACT FROM AUTHOR]

Purpose: Interval-training sets may be applied in a different sequence within a swimming training session. The aim of this study was to investigate the effect of different set sequences on performance and physiological responses in a training session. Methods: Twelve highly trained male swimmers performed 4 sessions in randomized order. Each session included a different combination of 2 training sets: set A–set C, set C–set A, set B–set C, or set C–set B. Set A consisted of 8 × 200 m at speed corresponding to lactate threshold (30-s recovery), set B included 8 × 100 m at maximum aerobic speed (30-s recovery), and set C included 4 × 50-m all-out swimming (2-min recovery). Performance and physiological responses (lactate concentration, pH, base excess, bicarbonate, heart rate, and heart-rate variability) were measured. Results: Performance in each set was similar between sessions irrespective of set sequence. Blood lactate, heart rate, and acid–base responses during set C were similar in all sessions, but blood lactate was higher in sets A and B during C–A and C–B sessions (P =.01). The overall blood lactate and acid–base response was higher in C–A and C–B sessions compared with A–C and B–C sessions, respectively (P =.01). Heart-rate variability in each set, separately as well as the overall session effect, did not differ and was thus independent to the set sequence applied. Conclusions: Training sessions including all-out swimming as a first set increase the magnitude of metabolic responses to the subsequent aerobic-dominated training set. [ABSTRACT FROM AUTHOR]

Purpose: The study examined the longitudinal interplay of anthropometric, metabolic, and neuromuscular development related to performance in adolescent national-level swimmers over 12 months. Methods: Seven male and 12 female swimmers (14.8 [1.3] y, FINA [International Swimming Federation] points 716 [51]) were tested before (T0) and after the preparation period (T1), at the season's peak (T2), and before the next season (T3). Anthropometric (eg, fat percentage) and neuromuscular parameters (squat and bench-press load-velocity profile) were assessed on dry land. Metabolic (cost of swimming [C], maximal oxygen uptake [ V ˙ O 2 peak ], and peak blood lactate [bLapeak]) and performance (sprinting speed [vsprint] and lactate thresholds [LT1 and 2]) factors were determined using a 500-m submaximal, 200-m all-out, 20-second sprint, and incremental test (+0.03 m·s−1, 3 min), respectively, in front-crawl swimming. Results: vsprint (+0.6%) and LT1 and 2 (+1.9–2.4%) increased trivially and slightly, respectively, from T0 to T2 following small to moderate strength increases (≥+10.2%) from T0 to T1 and V ˙ O 2 peak (+6.0%) from T1 to T2. Bench-press maximal strength and peak power correlated with vsprint from T0 to T2 (r ≥.54, P <.05) and LT2 at T1 (r ≥.47, P <.05). Changes in fat percentage and V ˙ O 2 peak (T2–T1 and T3–T2, r ≤ −.67, P <.01) and C and LT2 (T2–T0, r = −.52, P =.047) were also correlated. Conclusions: Increases in strength and V ˙ O 2 peak from preparation to the competition period resulted in improved sprint and endurance performance. Across the season, upper-body strength was associated with vsprint and LT2, although their changes were unrelated. [ABSTRACT FROM AUTHOR]

Purpose: Quantifying training intensity provides a comprehensive understanding of the training stimulus. Recent technological advances may have improved the feasibility of using heart-rate (HR) monitoring in swimming. However, the implementation of HR monitoring is yet to be assessed longitudinally in the daily training environment of swimmers. This study aimed to assess the implementation of HR by comparing the training-intensity distribution from an external measure, planned volume at set intensities (PVSI), with the internal training-intensity distribution measured using time in HR zones. Methods: Using a longitudinal observational design, 10 competitive swimmers (8 male and 2 female, age: 22.0 [2.3] y, Fédération Internationale de Natation point score: 842.9 [58.5], mean [SD]) were monitored daily for 6 months. Each session, HR data, and coached-planned and athlete-reported session rating of perceived exertion (Modified Category Ratio 10 scale) were recorded. Based on previously determined training zones from an incremental step test, PVSI was calculated using the planned distance and planned intensity of each swim bout. Training-intensity distributions were analyzed using a linear mixed model (lme4). Results: The model revealed a small to moderate relationship between PVSI and time in HR zone, based on the Nakagawa R-squared value (range.14–.42). Conclusions: Training-intensity distribution differed between the internal measure (ie, HR) and the external measure of intensity (ie, PVSI). This demonstrates that internal and planned external measures of intensity cannot be used interchangeably to monitor training. Further research should explore how to best integrate these measures to better understand training in swimming. [ABSTRACT FROM AUTHOR]

Purpose: This study investigated within- and between-matches blood lactate (La−) responses across an international Rugby Sevens tournament (5 matches over 2 d) in male and female players. Methods: Earlobe blood samples were taken from 25 professional players around matches: before warm-up (PRE), immediately upon finishing match participation (POST), and 30 minutes postmatch (30 min). Results: POST [La−] (mean [SD], range) for males was 10.3 (3.2; 2.9–20.2) mmol·L−1 and for females was 9.1 (2.3; 3.4–14.6) mmol·L−1. Linear mixed-effects models revealed a decrease in POST [La−] after match 5, compared to match 1. Increased PRE [La−] was found before match 2 (+0.8 [0.6–1.1] mmol·L−1), match 3 (+0.8 [0.5–1.1] mmol·L−1), and match 5 (+0.6 [0.4–0.9] mmol·L−1) compared to match 1 (all P <.001). The [La−] remained elevated at 30 min, compared to PRE (+1.7 [1.4–2.0] mmol·L−1, P <.001), with ∼20% of values persisting >4 mmol·L−1. Higher POST was observed in males compared to females (+1.6 [0.1–3.2] mmol·L−1, P =.042); however, no differences between sexes were found across 30 min or PRE [La−]. No [La−] differences between positions (backs and forwards) were identified. Conclusions: Lactate concentrations above 10 mmol·L−1 are required to effectively simulate the anaerobic demands of international Rugby Sevens matches. Practitioners are advised to individualize anaerobic training prescription due to the substantial variability observed within positional groups. Additionally, improving athletes' metabolic recovery capacity through training, nutrition, and recovery interventions may enhance physical preparation for subsequent matches within a day, where incomplete lactate clearance was observed. [ABSTRACT FROM AUTHOR]

Purpose: To determine whether competitive performance, as defined by International Biathlon Union (IBU) and International Ski Federation (FIS) points in biathlon and cross-country (XC) skiing, respectively, can be projected using a combination of anthropometric and physiological metrics. Shooting accuracy was also included in the biathlon models. Methods: Data were analyzed using multivariate methods from 45 (23 female and 22 male) biathletes and 202 (86 female and 116 male) XC skiers who were all members of senior national teams, national development teams, or ski-university or high school invite-only programs (age range: 16–36 y). Anthropometric and physiological characteristics were assessed via dual-energy X-ray absorptiometry and incremental roller-ski treadmill tests, respectively. Shooting accuracy was assessed via an outdoor standardized testing protocol. Results: Valid projective models were identified for female biathletes' IBU points (R2 =.80/Q2 =.65) and female XC skiers' FIS distance (R2 =.81/Q2 =.74) and sprint (R2 =.81/Q2 =.70) points. No valid models were identified for the men. The most important variables for the projection of IBU points were shooting accuracy, speeds at blood lactate concentrations of 4 and 2 mmol·L−1, peak aerobic power, and lean mass. The most important variables for the projection of FIS distance and sprint points were speeds at blood lactate concentrations of 4 and 2 mmol·L−1 and peak aerobic power. Conclusions: This study highlights the relative importance of specific anthropometric, physiological, and shooting-accuracy metrics in female biathletes and XC skiers. The data can help to identify the specific metrics that should be targeted when monitoring athletes' progression and designing training plans. [ABSTRACT FROM AUTHOR]

Aim: To quantify the physiological demands and impact of muscle function t of the Fran workout, one of the most popular CrossFit benchmarks. Methods: Twenty experienced CrossFitters—16 male: 29 (6) years old and 4 female: 26 (5) years old— performed 3 rounds (with 30-s rests in between) of 21–21, 15–15, and 9–9 front squats to overhead press plus pull-up repetitions. Oxygen uptake and heart rate were measured at baseline, during the workout, and in the recovery period. Rating of perceived exertion, blood lactate, and glucose concentrations were assessed at rest, during the intervals, and in the recovery period. Muscular fatigue was also monitored at rest and at 5 minutes, 30 minutes, and 24 hours postexercise. Repeated-measures analysis of variance was performed to compare time points. Results: Aerobic (52%–29%) and anaerobic alactic (30%–23%) energy contributions decreased and the anaerobic lactic contribution increased (18%–48%) across the 3 rounds of the Fran workout. Countermovement jump height decreased by 8% (−12 to −3) mean change (95% CI), flight duration by 14% (−19 to −7), maximum velocity by 3% (−5 to −0.1), peak force 4% (−7 to −0.1), and physical performance (plank prone 47% [−54 to −38]) were observed. Conclusions: It appears that the Fran workout is a physically demanding activity that recruits energy from both aerobic and anaerobic systems. This severe-intensity workout evokes substantial postexercise fatigue and corresponding reduction in muscle function. [ABSTRACT FROM AUTHOR]

Purpose: To identify differences in heart rate (HR) and concentration of blood lactate ([La]) relationships between laboratory- and field-based skate-roller-skiing tests. Methods: Fourteen world-class biathletes (8 women, 6 men) completed a laboratory- and field-based roller-skiing test using the skate technique. The laboratory-based test comprised 5 to 7 submaximal steps at a fixed incline and speed on a roller-skiing treadmill. The field-based test comprised 5 steps on a course where the final hill was designed to mimic the conditions of the laboratory test. HR and [La] were measured for each step. The HR associated with 2 mmol·L−1 (HR@2 mmol) and 4 mmol·L−1 (HR@4 mmol) of [La] was calculated using an interpolation method. A 1-way analysis of variance and Bland–Altman analyses with 95% limits of agreement (LoA) were used to determine if test type influenced HR@2 mmol or HR@4 mmol. A second-order polynomial was fitted to group-level data to highlight the HR–[La] relationships for laboratory- and field-based tests. Results: HR@2 mmol was lower for field tests than for laboratory tests (mean bias: 1.9%HRmax; 95% LoA: −4.5 to +8.3%HRmax; P <.001). HR@4 mmol was also lower for field tests compared to laboratory tests (mean bias: 2.4%HRmax; 95% LoA: −1.2 to +6.0%HRmax; P <.001). On the group level, the lactate threshold occurred at a lower HR during roller skiing in the field compared to the laboratory. Conclusions: The findings from this study confirm that for a given HR, [La] was greater in field- compared with laboratory-based conditions. These results might have implications for how coaches define training-intensity "zones" during skate roller skiing based on laboratory tests. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the study was to analyze physiological and energetic demands of elite gymnasts during still-rings routines (SRRs). Methods: Eleven male gymnasts (mean [SD] 23.6 [3.9] y, 65.9 [5.6] kg, 171.1 [6.7] cm) performed a maximal graded exercise test and an individual SRR, during which respiratory gas and heart rate (HR) were measured using a mobile spiroergometer and a paired HR sensor. Metabolic energy and the energy contribution in terms of aerobic, anaerobic lactic, and anaerobic alactic were determined by oxygen uptake (VO2) during exercise, net lactate production, and the fast component of postexercise VO2 kinetics. Results: Mean routine duration of the SRRs was 48.3 (4.5) seconds. VO2 and HR during SRRs were shown to be 86.9% (5.9%) and 91.0% (3.3%), respectively, of the maximal values measured during the graded exercise test. The anaerobic alactic, aerobic, and anaerobic lactic systems provided 50.9% (6.6%), 28.6% (4.8%), and 20.5% (5.2%), respectively, of the total energy required during SRRs. The energy contribution of the anaerobic lactic system correlated negatively with individual anaerobic threshold (r = −.715) and maximal VO2 (r = −.682). Conclusions: The anaerobic alactic system is the predominant energy source for ATP resynthesis during SRRs. The high relative VO2 and HR values reached during SRRs show that these routines strongly stress the cardiovascular system. [ABSTRACT FROM AUTHOR]

Purpose: To examine the effects of a high-carbohydrate diet (HCHO), periodized-carbohydrate (CHO) diet (PCHO), and ketogenic low-CHO high-fat diet (LCHF) on training capacity. Methods: Elite male racewalkers completed 3 weeks of periodic training while adhering to their dietary intervention. Twenty-nine data sets were collected from 21 athletes. Each week, 6 mandatory training sessions were completed, with additional sessions performed at the athlete's discretion. Mandatory sessions included an interval session (10 × 1-km efforts on a 6-min cycle), tempo session (14 km with a 450-m elevation gain), 2 long walks (25–40 km), and 2 easy walks (8–12 km) where "sleep-low" and "train-low" dietary strategies were employed for PCHO. Racewalking speed, heart rate, rating of perceived exhaustion, and blood metabolites were collected around key sessions. Results: LCHF covered less total distance than HCHO and PCHO (P <.001); however, no differences in training load between groups were evident (P =.285). During the interval sessions, walking speed was slower in LCHF (P =.001), equating to a 2.8% and 5.6% faster speed in HCHO and PCHO, respectively. LCHF was also 3.2% slower in completing the tempo session than HCHO and PCHO (P =.001). Heart rate was higher (P =.002) and lactate concentrations were lower (P <.001) in LCHF compared to other groups, despite slower walking speeds during the interval session. No between-groups differences in rating of perceived exhaustion were evident (P =.077). Conclusion: Athletes adhering to an LCHF diet showed impaired training capacity relative to their high-CHO-supported counterparts, completing lower training volumes at slower speeds, with higher heart rates. [ABSTRACT FROM AUTHOR]

In the field of optical bonding, traditional optical adhesives typically contain toxic organic polymers and solvents, limiting their widespread application. Hence, there is an urgent need for environmentally friendly aqueous adhesives. While there have been efforts to develop green adhesives, few report their performances with optical substrates. The unique requirements for optical adhesives include: optically transparent; the refractive index match of the substrate; minimal stress during and after curing. This presents a challenge to ensure compatibility between green and optical. This study introduces a novel sol-gel adhesive derived from an Al 2 O 3 –P 2 O 5 -lactate system. This adhesive is biocompatible, uses water as the sole solvent. It exhibits exceptional optical clarity, with more than 99 % transparency in the visible light and near-infrared regions. Furthermore, it provides reliable bonding strength, particularly when bonded with sapphire crystal substrates, reaching a maximum of 5.96 MPa. Interfacial chemistry analysis reveals the critical role of acidic components (such as phosphoric and lactate groups) in adhesives accounted for the bonding mechanism. By increasing the molar ratio of phosphoric acid, the bonding strength of adhesive was significantly enhanced across various substrates. This sol-gel adhesive not only adheres to green chemistry principles but also shows promising potential for optical bonding applications. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the applicability of the Lactate Threshold (LT) to predict maximal oxygen uptake (˙VO2max) and demarcate the boundary between the moderate- to heavy- intensity domain (HRm-h) in old age in comparison to the most utilized methods. A cross-sectional validation study was conducted. Participants aged 61 to 77 performed a familiarization procedure, an incremental maximal exercise treadmill test (CPX) for ˙VO2max determination, the Six-minute Walk Test (6MWT), and a discontinuous incremental field test for LT determination. Lower (P<0.01) internal effort was required for LT testing (76±8%HRmax) compared to 6MWT (92±9%HRmax). The application of the 6MWT reference equations overestimated ˙VO2max by 10–23%. LTs better estimated the ˙VO2max (r ≈0.90, SEE: ≈3.0] compared to the 6MWT (r=0.68, SEE=5.5). HRm-h determined by the CPX differed (20%; P=0.001) from that obtained by LT. HRm-h stratification indicated participants fall into the very light to the vigorous intensity domains. LT testing is more submaximal than the 6MWT, and is a valuable tool to estimate the ˙VO2max in older male adults. Implementation of LT testing in physical activity programs might help improving the quality of aerobic exercise training in older men. [ABSTRACT FROM AUTHOR]

Heart tumors are sporadic. Secondary heart tumors are 30 times more common than primary ones. Depending on the location and origin of the tumor, clinical pictures vary from asymptomatic to severe manifestations such as arrhythmia, heart failure, pericardial effusion, and cardiogenic shock. We report hereby a rare case who presented with faint clinical symptoms, rapidly progressing to right heart failure within a month. Echocardiography and computed tomography of the chest revealed a tumor in the right heart chamber of 72.0 × 43.0 mm, in addition to large mediastinal lymph and left supraclavicular lymph nodes, cardiogenic shock appeared 4 days after admission. Through examination, it was suspected that this was a cardiac lymphoma. The patient was treated with 2 mg methylprednisolone per kg body weight. Symptoms of cardiogenic shock improved significantly and disappeared after 6 hours of treatment. After supraclavicular lymph node biopsy and immunohistochemistry, the final result was diagnosed as diffuse large B-cell non-Hodgkin lymphoma with large lymphoma in the right heart. The patient received chemotherapy with the R-CHOP regimen (Rituximab, Cyclophosphamide, Doxorubicin, Vincristine, and Prednisolone). Re-examination before the 5th chemotherapy cycle showed no signs of right heart failure, normal self-activity, and no dyspnea on exertion, and the tumor size in the heart on the echocardiogram was 23.8 × 19.1 mm. The report shows that a large right heart tumor with a clinical picture of cardiogenic shock in a patient with diffuse large B-cell non-Hodgkin's lymphoma was well-responded to initial treatment with methylprednisolone at a dose of 2 mg/kg body weight and R-CHOP chemotherapy. [ABSTRACT FROM AUTHOR]

Independent risk factors for sepsis‐associated acute kidney injury (S‐AKI) patients include elevated lactate levels, but the specific mechanism remains unclear. Recently, An et al. discovered that excessive acetylation and inactivation of PDHA1 lead to overproduction of lactate, resulting in mitochondrial fragmentation, ATP depletion, excessive mtROS production, and mitochondrial apoptosis, thereby exacerbating AKI in sepsis. Therefore, understanding the pathophysiological processes of mitochondrial function and lactate generation in SAKI is essential and can aid in the development of novel therapeutic strategies. This review elucidates the pathological mechanisms of mitochondrial autophagy and dynamics in AKI. We also discuss the sources of lactate in SAKI and some consequences of lactonization, which may provide new strategies for improving renal injury and delaying the progression of these diseases. [ABSTRACT FROM AUTHOR]

In conjunction with the pressing global issue of climate change and the associated concern over global warming, increasing interest has emerged in the exploration of carbon dioxide (CO2) as a resource for the generation of a diverse array of products intended to serve societal needs. This study presents the development of an ATP-free and NAD-balanced in vitro synthetic enzymatic biosystem (ivSEB), which comprises only five cascade thermophilic enzymes, designed for the synthesis of L-malate through CO2 fixation powered by the utilization of D-glucose as a substrate. This designed ivSEB yields two moles of L-malate from one mole of D-glucose and two moles of CO2. Through meticulous refinement of reaction conditions and enzyme loading amounts, this ivSEB has demonstrated its capability to produce 6.85 mM of L-malate via CO2 fixation from an initial 5 mM of D-glucose with a molar product yield of 68.5%, and 2.45 mM of L-lactate as a byproduct. In the pursuit of assessing the industrial feasibility of this ivSEB, the study further subjected the system to the utilization of a high concentration (45.70 mM) of D-glucose. Although this endeavor necessitates additional optimization for enhanced efficiency, the present findings herald the emergence of an alternative avenue for the sustainable production of L-malate through CO2 fixation, thus bearing substantial promise for addressing ecological and industrial imperatives. [ABSTRACT FROM AUTHOR]

ABSTRACT Objectives Methods Results Conclusion The role of glycogen synthase kinase (GSK)‐3β in adult T‐cell leukemia (ATL) caused by human T‐cell leukemia virus type 1 (HTLV‐1) is paradoxical and enigmatic. Here, we investigated the role of GSK‐3β and its potential as a therapeutic target for ATL.Cell proliferation/survival, cell cycle, apoptosis, and reactive oxygen species (ROS) generation were examined using the WST‐8 assay, flow cytometry, and Hoechst 33342 staining, respectively. Expression of GSK‐3β and cell cycle/death‐related proteins, and survival signals was analyzed using RT‐PCR, immunofluorescence staining, and immunoblotting.HTLV‐1‐infected T‐cell lines showed nuclear accumulation of GSK‐3β. GSK‐3β knockdown and its inhibition with 9‐ING‐41 and LY2090314 suppressed cell proliferation/survival. 9‐ING‐41 induced G2/M arrest by enhancing the expression of γH2AX, p53, p21, and p27, and suppressing the expression of CDK1, cyclin A/B, and c‐Myc. It induced caspase‐mediated apoptosis by decreasing the expression of Bcl‐xL, Mcl‐1, XIAP, c‐IAP1/2, and survivin, and increasing the expression of Bak and Bax. 9‐ING‐41 also induced ferroptosis and necroptosis, promoted JNK phosphorylation, and suppressed IKKγ and JunB expression. It inhibited the phosphorylation of IκBα, Akt, and STAT3/5, induced ROS production, and reduced glycolysis‐derived lactate levels.GSK‐3β functions as an oncogene in ATL and could be a potential therapeutic target. [ABSTRACT FROM AUTHOR]

Tumor reliance on glycolysis is a hallmark of cancer. Immunotherapy is more effective in controlling glycolysis-low tumors lacking lactate dehydrogenase (LDH) due to reduced tumor lactate efflux and enhanced glucose availability within the tumor microenvironment (TME). LDH inhibitors (LDHi) reduce glucose uptake and tumor growth in preclinical models, but their impact on tumor-infiltrating T cells is not fully elucidated. Tumor cells have higher basal LDH expression and glycolysis levels compared with infiltrating T cells, creating a therapeutic opportunity for tumor-specific targeting of glycolysis. We demonstrate that LDHi treatment (a) decreases tumor cell glucose uptake, expression of the glucose transporter GLUT1, and tumor cell proliferation while (b) increasing glucose uptake, GLUT1 expression, and proliferation of tumor-infiltrating T cells. Accordingly, increasing glucose availability in the microenvironment via LDH inhibition leads to improved tumor-killing T cell function and impaired Treg immunosuppressive activity in vitro. Moreover, combining LDH inhibition with immune checkpoint blockade therapy effectively controls murine melanoma and colon cancer progression by promoting effector T cell infiltration and activation while destabilizing Tregs. Our results establish LDH inhibition as an effective strategy for rebalancing glucose availability for T cells within the TME, which can enhance T cell function and antitumor immunity [ABSTRACT FROM AUTHOR]

For the upcycling of waste polyethylene terephthalate (PET), encompassing both colored and fabric PET materials, we investigated the Ir(triNHC)‐catalyzed dehydrogenative coupling of PET and methanol, leading to the production of sodium lactate with good yields. We proposed a sustainable method for isolating lactic acid from the catalytic reaction mixture of sodium lactate and regenerating the base using bipolar membrane electrodialysis (BMED). This isolation method demonstrated high effectiveness, achieving isolation of lactic acid while maintaining economic feasibility at $ 0.10 per kg of lactic acid, and enabling sustainable NaOH regeneration with complete resource circulation. We assessed the recyclability of the catalyst and elucidated the mechanism involving base‐mediated depolymerization and catalyst‐promoted dehydrogenation, highlighting the importance of triNHC ligands in enhancing catalytic activity. [ABSTRACT FROM AUTHOR]

All‐inorganic cesium lead triiodide perovskites (CsPbI3) have attracted increasing attention due to their good thermal stability, remarkable optoelectronic properties, and adaptability in tandem solar cells. However, N2‐filled glovebox is generally required to strictly control the humidity during film fabrication due to the moisture‐induced black‐to‐yellow phase transition, which remains a great hinderance for further commercialization. Herein, we report an effective approach via incorporating multifunctional ethacridine lactate (EAL) to mitigate moisture invasion and enable the fabrication of efficient inverted (p‐i‐n) CsPbI3 perovskite solar cells (PSCs) under ambient condition. It is revealed that the lactate anions accelerate the crystallization of CsPbI3, shortening the exposure time to moisture during film fabrication. Meanwhile, the conjugated backbone and multiple functional groups in the ethacridine cations can interact with I− and Pb2+ to reduce the undesired defects, stabilize the perovskite structure and facilitate the charge transport in the film. Moreover, EAL incorporation also leads to better energy alignment, thus favoring charge extraction at both upper and bottom interfaces. Consequently, the device efficiency and stability are enormously enhanced, with the champion efficiency reaching 21.08 %. This even surpasses the highest value reported for the devices fabricated in glovebox, representing a record efficiency of inverted all‐inorganic PSCs. [ABSTRACT FROM AUTHOR]

Introduction Many trauma patients die from hemorrhagic shock in the military and civilian settings. Although two-thirds of hemorrhagic shock victims die of reasons other than exsanguination, such as the consequent cytokine storm, anti-inflammatory therapies failed to be utilized. Apoptotic cell–based treatments enhance innate ability to exert systemic immunomodulation as demonstrated in several clinical applications and hence might present a novel approach in hemorrhagic shock treatment. Materials and Methods Twenty-two rats underwent a pressure-controlled hemorrhagic shock model and followed up for 24 hours. An infusion of apoptotic cells (Allocetra-OTS, Enlivex Therapeutics Ltd, Nes Ziona, Israel) was administered to the treatment group. Hemodynamics, blood counts, biochemistry findings, and cytokine profile were compared to a saline-resuscitated control group. Results The treatment group's mean arterial pressure decreased from 94.8 mmHg to 28.2 mmHg, resulting in an 8.13 mg/dL increase in lactate and a 1.9 g/L decrease in hemoglobin, similar to the control group. White blood cells and platelets decreased more profoundly in the treatment group. A similar cytokine profile after 24 hours was markedly attenuated in the treatment group 2 hours after bleeding. Levels of pro-inflammatory cytokines such as interleukin (IL)-1a (28.4 pg/mL vs. 179.1 pg/mL), IL-1b (47.4 pg/mL vs. 103.9 pg/mL), IL-6 (526.2 pg/mL vs. 3492 pg/mL), interferon γ (11.4 pg/mL vs. 427.9 pg/mL), and tumor necrosis factor α (19.0 pg/mL vs. 31.7 pg/mL) were profoundly lower in the treatment group. Conclusion In a pressure-control hemorrhagic shock model in rats, apoptotic cell infusion showed preliminary signs of a uniform attenuated cytokine response. Apoptotic cell–based therapies might serve as a novel immunomodulatory therapy for hemorrhagic shock. [ABSTRACT FROM AUTHOR]

Moringa oleifera Lam. leaves contain various nutrients and bioactive compounds. The present study aimed to assess the anti-fatigue capacity of a flavonoids concentrate purified from M. oleifera Lam. leaves. The total flavonoids in the purified extract were analyzed by ultra-performance liquid chromatography electrospray ionization tandem mass spectrometry (UPLC-MS/MS). The mice were supplemented with purified M. oleifera Lam. leaf flavonoid-rich extract (MLFE) for 14 days. The weight-loaded forced swimming test was used for evaluating exercise endurance. The 90-min non-weight-bearing swimming test was carried out to assess biochemical biomarkers correlated to fatigue and energy metabolism. UPLC-MS/MS analysis identified 83 flavonoids from MLFE. MLFE significantly increased the swimming time by 60%. Serum lactate (9.9 ± 0.9 vs. 8.9 ± 0.7), blood urea nitrogen (BUN) (8.8 ± 0.8 vs. 7.2 ± 0.5), and nonesterified fatty acid (NEFA) (2.4 ± 0.2 vs. 1.7 ± 0.3) were significantly elevated; phosphoenolpyruvate carboxykinase (PEPCK), glucokinase (GCK), and nuclear factor erythroid 2-related factor 2 (Nrf2) mRNA expression were significantly downregulated; and heme oxygenase 1 mRNA expression was significantly upregulated in muscle after swimming. MLFE supplement significantly decreased serum lactate (8.0 ± 1.0 vs. 9.9 ± 0.9), BUN (8.6 ± 0.4 vs. 8.9 ± 0.8), and NEFA (2.3 ± 0.4 vs. 2.4 ± 0.2) and increased the protein and mRNA expression of GCK, PEPCK, and Nrf2. The enhancement of glucose metabolism and antioxidant function by MLFE contributes partly to its anti-fatigue action. [ABSTRACT FROM AUTHOR]

Competitive collegiate dance combines elements of gymnastics and acrobatics with more traditional styles, such as ballet, jazz, and modern dance. Assessing the physiological demands and identifying clear measures of intensity and duration of such dance provide a framework for planning the competitive season and developing strength and conditioning programs. This study examined the blood lactate (BL), heart rate (HR), and ratings of perceived exertion (RPE) of 14 well-trained female dancers on a competitive collegiate dance team. Subjects completed a treadmill test to determine their lactate threshold (LT) and then performed a 120-second choreographed jazz dance routine in cumulative 30-second segments, during which physiological markers were measured. All subjects exceeded their individually determined LT values by 90 seconds into the dance routine. A moderate (rs = 0.53; p < 0.001) positive correlation was observed between HR and RPE, as was a strong (rs = 0.70; p < 0.001) positive correlation between BL and RPE. Subjects worked at or above LT for much of the 120-second jazz dance routine, indicating that competitive collegiate dance is physiologically demanding and highly anaerobic. Understanding the physiological demands of competitive collegiate dance allows strength and conditioning professionals to develop, monitor, and adjust training parameters, which will aid in minimizing injury and maximizing competitive performance in collegiate dancers. [ABSTRACT FROM AUTHOR]

Longer rest intervals between resistance exercise (RE) sets may promote greater muscle hypertrophy and strength gains over time by facilitating the completion of greater training volume and intensity. However, little is known about the acute neuro-muscular responses to RE sets incorporating longer vs. shorter rest intervals. Using a within-subject, crossover design, 8 healthy, young subjects completed 2 separate acute bouts of 4 sets of 8 x 3-s maximal isometric contractions using either a 2-minute (REST-2) or 5-minute (REST-5) rest interval between sets. Peak torque (PT) and electromyography (EMG) were measured pre and 5 minutes postexercise. Peaktorque and mean torque (MT), EMG, mean, and median frequencies were measured during each set, whereas blood lactate (BLa), heart rate (HR), and rating of perceived exertion (RPE) were measured following each set. Peaktorque and MT were lower (p < 0.05) in sets 3 and 4, and sets 2-4 in REST-2 compared with REST-5, respectively. Electromyography and BL were lower and higher, respectively, in REST-2 vs. REST-5. There was no main effect of condition on HR or RPE. Pre-to-post exercise reductions in PT (-17 ± 9% vs. -4 ± 7%) and EMG (-29 ± 14% vs. -10 ± 7%) were greater (p < 0.001) in REST-2 vs. REST-5. Total exercise volume was less in REST-2 vs. REST-5 (9,748 ± 2296 N⋅m-1 vs. 11,212 ± 2513 N⋅m-1, p < 0.001). These results suggest that incorporating 5-minute between-set rest intervals into a resistance exercise session facilitates improved neuromuscular function, increased exercise volume, and less metabolic stress compared with 2-minute rest intervals. Thus, 5-minute rest intervals may be more efficacious for promoting muscle hypertrophy and strength gains in a chronic resistance training program. [ABSTRACT FROM AUTHOR]

Background: Acquired multidrug resistance is often blamed for the failure of chemotherapy in patients with malignant tumors, including chronic myeloid leukemia (CML). In this study, the authors investigated the role of circular RNA 0080145 (circ_0080145) in imatinib (IM) resistance of CML. Materials and Methods: Quantitative real-time polymerase chain reaction was applied to measure the expression of circ_0080145, microRNA-326 (miR-326), and PTPRF interacting protein alpha 1 (PPFIA1) mRNA. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay was used to determine the half maximal inhibitory concentration (IC50) of IM and cell proliferation. Flow cytometry analysis was utilized to assess cell apoptosis. The levels of glucose uptake and lactate production were examined using specific kits. Protein levels were detected through Western blot assay. The targeting relationship between miR-326 and circ_0080145 or PPFIA1 was verified by dual-luciferase reporter assay. The murine xenograft model was constructed to investigate the effect of circ_0080145 in vivo. Results: circ_0080145 was upregulated in IM-resistant CML patients and cells. circ_0080145 silencing suppressed IM resistance, cell growth, and glycolysis and induced apoptosis in IM-resistant CML cells in vitro. Moreover, circ_0080145 knockdown blocked tumor growth and IM resistance in vivo. miR-326 was a target of circ_0080145, and miR-326 inhibition restored the effects of circ_0080145 silencing on cell progression and IM resistance. In addition, PPFIA1 was a target gene of miR-326. The suppressive roles in IM resistance, cell growth and glycolysis, and the promotional role in apoptosis mediated by miR-326 were abolished by PPFIA1 overexpression in IM-resistant CML cells. Conclusion: circ_0080145 contributes to IM resistance via modulating miR-326/PPFIA1 axis, which might provide a novel avenue for CML therapy. [ABSTRACT FROM AUTHOR]

Background: Nutrition guidance for athletes must consider a range of variables to effectively support individuals in meeting energy and nutrient needs. Resistance exercise is a widely adopted training method in athlete preparation and rehabilitation and therefore is one such variable that will influence nutrition guidance. Given its prominence, the capacity to meaningfully quantify resistance exercise energy expenditure will assist practitioners and researchers in providing nutrition guidance. However, the significant contribution of anaerobic metabolism makes quantifying energy expenditure of resistance exercise challenging. Objective: The aim of this scoping review was to investigate the methods used to assess resistance exercise energy expenditure. Methods: A literature search of Medline, SPORTDiscus, CINAHL and Web of Science identified studies that included an assessment of resistance exercise energy expenditure. Quality appraisal of included studies was performed using the Rosendal Scale. Results: A total of 19,867 studies were identified, with 166 included after screening. Methods to assess energy expenditure included indirect calorimetry (n = 136), blood lactate analysis (n = 25), wearable monitors (n = 31) and metabolic equivalents (n = 4). Post-exercise energy expenditure was measured in 76 studies. The reported energy expenditure values varied widely between studies. Conclusions: Indirect calorimetry is widely used to estimate energy expenditure. However, given its limitations in quantifying glycolytic contribution, indirect calorimetry during and immediately following exercise combined with measures of blood lactate are likely required to better quantify total energy expenditure. Due to the cumbersome equipment and technical expertise required, though, along with the physical restrictions the equipment places on participants performing particular resistance exercises, indirect calorimetry is likely impractical for use outside of the laboratory setting, where metabolic equivalents may be a more appropriate method. [ABSTRACT FROM AUTHOR]

BACKGROUND Delivery by caesarean section is common in recent times and subarachnoid block is the technique of choice due to its simplicity and reliability. However, it can cause hypotension which is associated with increased morbidity and mortality. Preloading the parturient with colloid is more effective than crystalloid in preventing the hypotension. Among the commercially available colloids 6% Pentastarch in 0.9% saline has the best safety profile. In this study, we compared the efficacy of 10ml/kg Ringer’s lactate to that of 10ml/kg 6% Pentastarch in preventing the incidence and severity of hypotension in parturients undergoing LSCS under SAB. MATERIAL AND METHODS After the ethical committee's approval, a randomized study was conducted on 114 parturients (aged between 20 -32 years) and divided into two groups. Group P - 6% Pentastarch 10ml/kg IV and Group R - Ringer’s Lactate 10ml/kg IV. Study drugs were administered intravenously over 20 minutes before the performance of the subarachnoid block. HR, SBP, DBP, MAP and SPO2 were noted every minute for the first 10 minutes, thereafter for every 5 mins till the end of surgery. RESULTS The mean HR of group P was better maintained than that of group R. A statistically significant fall in SBP was seen with group R more than group P at the 2nd, 4th, 6th, 7th, 10th and 40th minute. Group P had significantly less fall in DBP and MAP than group R. CONCLUSION Our study demonstrates that 6% Pentastarch is better preloading fluid than Ringer’s lactate in preventing hypotension in parturients undergoing elective caesarean section under subarachnoid block. [ABSTRACT FROM AUTHOR]

Regional citrate anticoagulation (RCA) is a preferred method for continuous renal replacement therapy (CRRT) due to its benefits of extended filter lifespan and reduced bleeding complications. However, RCA can cause metabolic side effects such as alkalosis, acidosis, hypotension, and electrolyte imbalances. Optimal anticoagulation requires careful adjustment of citrate infusion based on blood flow rate. Citrate accumulation can occur in certain conditions, leading to adverse effects. Strategies for adapting citrate anticoagulation include adjusting the dose based on the patient's condition. The Cori cycle has been proposed as an alternative pathway for citrate metabolism outside the liver mitochondria. Establishing thresholds for citrate initiation is important, and lactate levels can be used as an indicator of impaired citrate metabolism. The proposed hypothesis of an alternative inducible citrate metabolism pathway requires further research, including an animal model, to validate its effectiveness. Overall, RCA is a viable option for patients with liver failure, and further research is needed to optimize its application and improve anticoagulation strategies in various clinical contexts. [Extracted from the article]

Since assessing aerobic capacity is key to enhancing swimming performance, a simple and widely applicable technology should be developed. Therefore, we aimed to noninvasively visualize real‐time changes in sweat lactate (sLA) levels during swimming and investigate the relationship between lactate thresholds in sweat (sLT) and blood (bLT). This prospective study included 24 university swimmers (age: 20.7 s ± 1.8 years, 58% male) who underwent exercise tests at incremental speeds with or without breaks in a swimming flume to measure heart rate (HR), bLT, and sLT based on sLA levels using a waterproof wearable lactate sensor attached to the dorsal upper arm on two different days. The correlation coefficient and Bland–Altman methods were used to verify the similarities of the sLT with bLT and personal performance. In all tests, dynamic changes in sLA levels were continuously measured and projected onto the wearable device without delay, artifacts, or contamination. Following an initial minimal current response, with increasing speed the sLA levels increased substantially, coinciding with a continuous rise in HR. The speed at sLT strongly correlated with that at bLT (p < 0.01 and r = 0.824). The Bland–Altman plot showed a strong agreement (mean difference: 0.08 ± 0.1 m/s). This prospective study achieved real‐time sLA monitoring during swimming, even with vigorous movement. The sLT closely approximated bLT; both were subsequently validated for their relevance to performance. Highlights: A new technique using a wearable device can measure sweat lactate (sLA) levels during swimming without artifacts or contamination.Lactate threshold assessed using sLA dynamics is consistent with that calculated from blood samples.The current novel measurement method is expected to promote a personalized training regimen and simultaneous multi‐person measurements. [ABSTRACT FROM AUTHOR]

Background: Anastomotic leakage (AL) is a dreaded complication following colorectal cancer surgery, impacting patient outcome and leads to increasing healthcare consumption as well as economic burden. Bowel perfusion is a significant modifiable factor for anastomotic healing and thus crucial for reducing AL. Aims: The study aimed to calculate a cut-off value for quantified laser speckle perfusion units (LSPUs) in order to differentiate between ischemic and well-perfused tissue and to assess inter-observer reliability. Methods: LSCI was performed using a porcine ischemic small bowel loop model with the PerfusiX-Imaging® system. An ischemic area, a well-perfused area, and watershed areas, were selected based on the LSCI colormap. Subsequently, local capillary lactate (LCL) levels were measured. A logarithmic curve estimation tested the correlation between LSPU and LCL levels. A cut-off value for LSPU and lactate was calculated, based on anatomically ischemic and well-perfused tissue. Inter-observer variability analysis was performed with 10 observers. Results: Directly after ligation of the mesenteric arteries, differences in LSPU values between ischemic and well-perfused tissue were significant (p < 0.001) and increased significantly throughout all following measurements. LCL levels were significantly different (p < 0.001) at both 60 and 120 min. Logarithmic curve estimation showed an R2 value of 0.56 between LSPU and LCL values. A LSPU cut-off value was determined at 69, with a sensitivity of 0.94 and specificity of 0.87. A LCL cut-off value of 3.8 mmol/L was found, with a sensitivity and specificity of 0.97 and 1.0, respectively. There was no difference in assessment between experienced and unexperienced observers. Cohen's Kappa values were moderate to good (0.52–0.66). Conclusion: Real-time quantification of LSPUs may be a feasible intraoperative method to assess tissue perfusion and a cut-off value could be determined with high sensitivity and specificity. Inter-observer variability was moderate to good, irrespective of prior experience with the technique. [ABSTRACT FROM AUTHOR]

Blood lactate concentration during exercise is a reliable indicator of energy metabolism and endurance performance. Lactate is also present in sweat, and sweating plays an important role in thermoregulation, especially in hot conditions. Recently, wearable sensors have enabled the real-time and noninvasive measurement of sweat lactate concentration, potentially serving as an alternative indicator of blood lactate response. However, the evidence regarding the relationship between sweat and blood lactate responses during incremental exercise in hot conditions is lacking. In a randomized cross-over design, six highly trained male runners completed two incremental treadmill tests under normal (20°C/50%RH) or hot (30°C/50%RH) conditions. The tests include 3-min running stages and 1-min recovery, starting at 12 km/h and increasing by 1 km/h at each stage. Blood and sweat lactate concentrations were measured at each stage to determine blood and sweat lactate thresholds (LT). Blood lactate concentrations were higher under hot conditions (p < 0.01), but there was no difference in the response pattern or velocity at blood LT between conditions. Significant early increase (p < 0.01) in sweat lactate and low velocity at sweat LT (p < 0.05) were observed under hot conditions. A significant correlation between blood and sweat lactate concentrations was found under normal conditions (p < 0.001) but not under hot conditions, and no significant correlations were observed between the velocity at blood and sweat LT. In conclusion, sweat lactate concentration does not consistently reflect blood lactate concentration during incremental exercise. [ABSTRACT FROM AUTHOR]

This article discusses the relationship between cardiac energy metabolism and cardiac function in obesity and type 2 diabetes. It highlights the advancements in studying cardiac energy metabolism, including the use of imaging techniques and the discovery of fatty acids as the primary fuel source for the heart. The article revisits a classic study by Aasum et al. that examined how obesity and type 2 diabetes affect cardiac energy metabolism. The study found that alterations in cardiac energy metabolism can directly lead to cardiac dysfunction. These findings have had a significant impact on our understanding of cardiac energy metabolism in obesity and type 2 diabetes. The article also discusses potential targets for pharmacotherapy to alleviate cardiovascular disease associated with obesity and type 2 diabetes. Future research in this field aims to explore the molecular mechanisms underlying these metabolic alterations and their effects on cardiac function. [Extracted from the article]

The article investigates how tumor cells use acetate to support their growth and evade the immune system. It shows that acetate is abundant in the tumor microenvironment and contributes to tumor cell proliferation and immune evasion by enhancing the acetylation of c-Myc, a key oncogenic protein. Topics include acetate's role in tumor metabolism, its impact on c-Myc acetylation and stabilization, and its effects on immune cell infiltration and tumor growth.

BACKGROUND: Aortic dissection (AD) is a serious cardiovascular condition associated with high mortality rates. The systemic inflammatory response can influence the prognosis of AD, and in this context, the neutrophil-to-lymphocyte ratio (NLR) emerges as a simple and rapid inflammatory biomarker. METHODS: This retrospective cohort study included 103 patients diagnosed with AD and treated in the emergency department between 2018 and 2023. Patient demographics, clinical features, and laboratory results were evaluated. Multivariate logistic regression analysis was performed to adjust for potential confounders such as age, mean systolic blood pressure, oxygen saturation, hemoglobin, lactate values, and the presence of coronary artery disease. The ability of NLR to predict mortality was analyzed using receiver operating characteristic (ROC) analysis. RESULTS: The study population was divided into two groups: non-survivors (68% mortality rate) and survivors (32% survival rate). The non-survivor group had significantly higher NLR values compared to the survivor group (median NLR 7.66 vs. 2.5, p<0.001). Multivariate logistic regression analysis identified NLR as an independent predictor of in-hospital mortality (adjusted odds ratio [OR] 2.33, 95% confidence interval [CI] 1.42-3.82, p<0.001). ROC analysis for NLR demonstrated high discriminative power with an area under the ROC curve (AUROC) of 0.851 (95% CI 0.768-0.914). The determined cut-off point was >5.08 with a sensitivity of 77.14% and specificity of 81.82%. CONCLUSION: The findings indicate that high NLR is strongly associated with increased mortality risk in patients with AD and can be used in emergency clinical settings to predict mortality. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the effects of contamination of venous blood with a lipid-containing solution on parameters measured by a modern blood gas analyzer. We collected venous blood from 17 healthcare workers (46 ± 11 years; 53 % women) into three blood gas syringes containing 0 , 5 and 10 % lipid-containing solution. Blood gas analysis was performed within 15 min from sample collection on GEM Premier 5000, while triglycerides and serum indices were assays on Roche COBAS C702. Triglycerides concentration increased from 1.0 ± 0.3 mmol/L in the uncontaminated blood gas syringe, to 39.4 ± 7.8 and 65.3 ± 14.4 mmol/L (both p<0.001) in syringes with 5 and 10 % final lipid contamination. The lipemic and hemolysis indices increased accordingly. Statistically significant variation was noted for all analytes except hematocrit and COHb in the syringe with 5 % lipids, while only COHb did not vary in the syringe with 10 % lipids. Significant increases were observed from 5 % lipid contamination for pO2, SO2 and lactate, while the values of pH, pCO2, sodium, potassium, chloride, ionized calcium, glucose, hematocrit (10 % contamination), hemoglobin and MetHB decreased. All these changes except lactate and CoHb exceeded their relative performance specifications. Artifactual hyperlipidemia caused by contamination with exogenous lipids can have a clinically significant impact on blood gas analysis. Manufacturers of blood gas analyzers must be persuaded to develop new instruments equipped with serum indices. [ABSTRACT FROM AUTHOR]

Purpose: In vivo quantification of lactate has numerous applications in studying the pathology of both cerebral and musculoskeletal systems. Due to its low concentration (~0.5–1 mM), and overlap with lipid signals, traditional 1H MR spectra acquired in vivo using a small voxel and short echo time often result in an inadequate signal to detect and resolve the lactate peak, especially in healthy human volunteers. Methods: In this study, using a semi‐LASER acquisition with long echo time (TE = 288 ms) and large voxel size (80 × 70 × 20 mm3), we clearly visualize the combined signal of lactate and threonine. Therefore, we call the signal at 1.33 ppm Lac+ and quantify Lac+ concentration from water suppressed spectra in healthy human brains in vivo. Four participants (22–37 years old; mean age = 28 ± 5.4; three male, one female) were scanned on four separate days, and on each day four measurements were taken. Intra‐day values are calculated for each participant by comparing the four measurements on a single day. Inter‐day values were calculated using the mean intra‐day measurements. Results: The mean intra‐participant Lac+ concentration, standard deviation (SD), and coefficient of variation (CV) ranged from 0.49 to 0.61 mM, 0.02 to 0.07 mM, and 4% to 13%, respectively, across four volunteers. The inter‐participant Lac+ concentration, SD, and CV was 0.53 mM, ±0.06 mM, and 11%. Conclusion: Repeatability is shown in Lac+ measurement in healthy human brain using a long echo time semi‐LASER sequence with a large voxel in about 3.5 min at 3 T. [ABSTRACT FROM AUTHOR]

Insufficient trophoblast migration and impaired uterine spiral artery remodeling are implicated in the pathogenesis of preeclampsia, contributing to inadequate placentation. However, the molecular mechanism underlying this process remains unclear. Aerobic glycolysis, which produces substantial lactate, is crucial for establishing a favorable microenvironment for early uterine preparation and supporting embryo implantation and trophoblast migration. In the present study, we have demonstrated that SORBS2, an RNA-binding protein, regulated aerobic glycolysis and significantly improved trophoblast migration in vitro. Our results showed that SORBS2 expression was significantly reduced in human PE placentas and trophoblasts during hypoxia. Overexpression of SORBS2 enhanced cell proliferation and migration, whereas knockdown of SORBS2 decreased these functions in HTR-8/SVneo cells. Mechanistic studies have demonstrated that SORBS2 directly interacts with the 3' untranslated regions (UTRs) of key glycolysis-related genes, specifically HK2. This interaction results in enhanced stability of HK2 and activation of glycolysis. Moreover, silencing HK2 abrogated the enhancement of proliferation and migration of HTR-8/SVneo cells induced by SORBS2. In conclusion, our findings suggest that the downregulation of SORBS2 may contribute to the pathogenesis of preeclampsia by regulating mRNA stability and inhibiting trophoblast migration during placentation. [ABSTRACT FROM AUTHOR]

Osteosarcoma is a very serious primary bone cancer with a high death rate and a dismal prognosis. Since there is no permanent therapy for this condition, it is necessary to develop a cure. Therefore, this investigation was carried out to assess the impacts and biological functions of hydroxysafflor yellow A (HYSA) in osteosarcoma cell lines (MG63). In this investigational study, MG63 cells were utilized. Microarray experiments, quantitative polymerase chain reaction (qPCR), immunofluorescent staining, extracellular acidification rate (ECAR), oxygen consumption rate (OCR), glucose consumption, lactate production, and ATP levels, proliferation assay, 5-Ethynyl-2'-deoxyuridine (EDU) staining, and Western blot were performed. In MG63 cells, HYSA lowered cell proliferation and metastasis rates, suppressed EDU cell number, and enhanced caspase-3/9 activity levels. HYSA reduced the Warburg effect and induced ferroptosis (FPT) in MG63 cells. Inhibiting ferroptosis diminished HYSA's anti-cancer activities in MG63 cells. The stimulation of the HIF-1a/SLC7A11 pathway decreased HYSA's anti-cancer activities in MG63 cells. HIF-1a is one target spot for HYSA in a model of osteosarcoma cancer (OC). HYSA altered HIF-1a's thermophoretic activity; following binding with HYSA, HIF-1a's melting point increased from ~55°C to ~60°C. HYSA significantly enhanced the thermal stability of exogenous WT HIF-1a while not affecting Mut HIF-1a, suggesting that ARG-311, GLY-312, GLN-347, and GLN-387 may be involved in the interaction between HIF-1a and HYSA. Conclusively, our study revealed that HYSA induced FPT and reduced the Warburg effect of OC through mitochondrial damage by HIF-1a/HK2/SLC7A11 pathway. HYSA is a possible therapeutic option for OC or other cancers. [ABSTRACT FROM AUTHOR]

Objectives. This systematic review aims to report the evaluation of wearable biosensors for the real-time measurement of stress and fatigue using sweat biomarkers. Methods. A thorough search of the literature was carried out in databases such as PubMed, Web of Science and IEEE. A three-step approach for selecting research articles was developed and implemented. Results. Based on a systematic search, a total of 17 articles were included in this review. Lactate, cortisol, glucose and electrolytes were identified as sweat biomarkers. Sweat-based biomarkers are frequently monitored in real time using potentiometric and amperometric biosensors. Wearable biosensors such as an epidermal patch or a sweatband have been widely validated in scientific literature. Conclusions. Sweat is an important biofluid for monitoring general health, including stress and fatigue. It is becoming increasingly common to use biosensors that can measure a wide range of sweat biomarkers to detect fatigue during high-intensity work. Even though wearable biosensors have been validated for monitoring various sweat biomarkers, such biomarkers can only be used to assess stress and fatigue indirectly. In general, this study may serve as a driving force for academics and practitioners to broaden the use of wearable biosensors for the real-time assessment of stress and fatigue. [ABSTRACT FROM AUTHOR]

Background: High lactate to albumin ratio (LAR) has been reported to be associated to with poor prognosis in patients admitted to the intensive care unit (ICU). However, its role in predicting in-hospital mortality in AF patients admitted to ICU has not been explored. Methods: The Medical Information Mart for Intensive Care-IV (MIMIC-IV) database was used to retrieve information on patients who had been diagnosed with AF. X-tile software was utilized to determine the optimal cut-off LAR. Area under the receiver operating characteristic curves (AUC), calibration plots, and decision curve analysis (DCA) were conducted to assess the prediction performance of LAR for in-hospital mortality. Results: Finally, 8,287 AF patients were included and 1,543 death (18.6%) occurred. The optimal cut-off value of LAR is 0.5. Patients in lower LAR (< 0.5) group showed a better in-hospital survival compared to patients in higher LAR (≥ 0.5) group (HR: 2.67, 95%CI:2.39–2.97, P < 0.001). A nomogram for in-hospital mortality in patients with AF was constructed based on multivariate Cox analysis including age, CCI, β blockers usage, APSIII, hemoglobin and LAR. This nomogram exhibited excellent discrimination and calibration abilities in predicting in-hospital mortality for critically ill AF patients. Conclusion: LAR, as a readily available biomarker, can predict in-hospital mortality in AF patients admitted to the ICU. The nomogram that combined LAR with other relevant variables performed exceptionally well in terms of predicting in-hospital mortality. [ABSTRACT FROM AUTHOR]

Objectives: This study assessed how exposure to slow (SBM) versus fast beat music (FBM) during high-intensity rowing intervals affects performance, heart rate (HR), lactate levels, relative perceived exertion (RPE), and recovery. Methods: The A/B crossover design involved 21 participants performing 5 × 500 m rowing intervals under two conditions: FBM and SBM. Primary endpoint was the difference in total rowing time. Secondary endpoints included average HR, average RPE as well as rowing interval times, RPE, and HR per interval. For exploratory purpose, HR and lactate drop during the initial 5 min post completion was analyzed. Results: Listening to FBM resulted in significantly shorter total rowing times (p = 0.009, rB = 0.59), especially during the 1st interval. The 1st interval was also significantly faster than intervals 2-5 (p < 0.001), with the greatest performance drop between the 1st and 2nd interval during FBM. Average HR was significantly lower when listening to SBM (p = 0.03, rB = 0.48), while average RPE showed no significant difference (p = 0.47, rB = 0.02). Lactate values after interval 5 were significantly lower in SBM (p = 0.05, rB = 0.41), but no significant difference was found for lactate drop (p = 0.21, rB = 0.21). However, participants exhibited a higher HR drop rate with SBM (p = 0.05, rB = 0.42). Conclusion: FBM improved performance without increasing RPE, while SBM proved superior for recovery. Systematic customization of music based on intended training stimuli holds broad potential for the competitive sports, fitness, and health sector. [ABSTRACT FROM AUTHOR]