Blood Lactate Responses Research Articles

Effect of Low vs. High Carbohydrate Intake after Glycogen-Depleting Workout on Subsequent 1500 m Run Performance in High-Level Runners.

Carbohydrate (CHO) metabolism is crucial for short-duration, high-intensity exercise performance, but the effects of variations in glycogen availability have not been investigated in field trials of trained athletes. This study was designed to test how 1500 m time trial (TT) performance is affected by the manipulation of pre-race glycogen reserves. Competitive middle-distance runners (n = 11 (4 females)) completed a 1500 m individually paced indoor TT after abundant (high, >5 g/kg/d) or restricted (low, <1.5 g/kg/d) dietary CHO intake for 2 days after a glycogen-depleting session. Stride pattern, heart rate (HR), capillary blood lactate, and glucose and plasma malondialdehyde (MDA) response were determined. The TT was slower in low vs. high condition by 4.5 (4.5) s (~2%; p < 0.01), with a tendency toward shorter stride length. Blood lactate and glucose were lower before the TT in low vs. high condition (1.8 (0.5) vs. 2.2 (0.7) mmol/L and 5.4 (0.7) vs. 5.9 (0.8) mmol/L, p = 0.022 and 0.007, respectively), and peak lactate was higher in high vs. low condition (16.8 (3.1) vs. 14.5 (4.2) mmol/L, p = 0.039). Plasma MDA was the same before the TT, and 15 min after the TT, it increased similarly by 15% in low (p = 0.032) and high (p = 0.005) conditions. The restriction of pre-test CHO intake impaired 1500 m TT performance and reduced baseline and peak blood lactate concentrations but not blood glucose or MDA response.

Higher Blood Lactate with Prolongation of Underwater Section in Submaximal Front-Crawl Swimming.

The underwater phase (UP) is highly important for overall swimming performance in most swimming events. However, the metabolic effects of the prolonged UP remain unclear. The purpose of this cross-sectional study was to compare the blood lactate response to submaximal front-crawl swimming with short and extended UP. Twelve (four females) junior competitive swimmers (aged 15.4 (1.4) years) undertook 200 m front-crawl swim trials in a 25 m pool at a pre-determined "anaerobic threshold" velocity on two occasions using short (<5 m) and extended (12.5 m) UP after each turn. Pacing and total time were ensured to be identical between the trials. Capillary blood lactate response was measured. Testing for 25 m swim time with <5 m and 12.5 m UP was conducted on a separate occasion. When athletes undertook and extended UP after each propulsion from the wall, their post-exercise blood lactate concentration reached 7.9 (2.1) mmol/L, more than two times higher than the response to trial with short UP (p < 0.001). All-out 25 m swimming with <5 m or 12.5 m UP disclosed no difference in locomotion velocity (p > 0.05). In conclusion, extending UP of submaximal front-crawl swimming close to maximally allowed during the races substantially increases blood lactate accumulation, i.e., increases the reliance on anaerobic metabolism. Therefore, extended UP is most likely counterproductive for the performance in long-distance swimming, at least for the athletes with a FINA score of <800. On the other hand, the extension of UP could be an effective strategy to train 'lactate tolerance', lactate shuttling, removal, and recycling.

Physiological Responses and Swimming-Performance Changes Induced by Altering the Sequence of Training Sets.

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. 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, orset C-set B. Set A consisted of 8 × 200m at speed corresponding to lactate threshold (30-s recovery), set B included 8 × 100m 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. 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. Training sessions including all-out swimming as a first set increase the magnitude of metabolic responses to the subsequent aerobic-dominated training set.

The lactate response to a second bout of exercise is not reduced in a concurrent lower-limb exercise program

We aimed to evaluate the blood lactate level in response to two bouts of exercise. First, we hypothesized that blood lactate elevation in response to moderate-intensity aerobic exercise (MIAE) would be lower at the end of the second bout of MIAE than the first bout of MIAE. In this context, we also hypothesized that lactate accumulation at the end of resistance exercise (RE) would be reduced if MIAE is performed before RE (i.e., concurrent exercise; CE). If so, we hypothesized that the order of the CE (i.e., RE + MIAE vs. MIAE + RE) influences blood lactate kinetics. To test the hypotheses, forty-three healthy men participated in three studies. In study 1, 20 men (age 21 ± 2 years) performed two bouts of a 20-min MIAE separated by a 20-min rest interval. In study 2, 11 men (age 22 ± 1 years) performed RE only and CE (MIAE + RE; ARCE) with a 20-min rest interval in a crossover design. In study 3, 12 men (age 21 ± 2 years) performed both CEs, which were ARCE and RE + MIAE (RACE), with a 20-min rest interval in a crossover design. We measured blood lactate before and at the end of each exercise session. In study 1, the blood lactate response to the second bout of MIAE was lower than that of the first bout (P < 0.001, r = 0.68). However, the blood lactate response to the ARCE trial was not lower than the response to the RE trial in study 2 (P = 0.475, r = 0.22). The results of study 3 showed that the RACE and ARCE trials induced a similar lactate response (MIAE P = 0.423, r = 0.28; RE P = 0.766, d = 0.03). These observations indicate that whereas lactate accumulation might be diminished by a second bout of MIAE, a different type of exercise (i.e., aerobic/resistance) did not result in a diminished lactate accumulation in response to a second bout of exercise.

Blood Lactate and Heart Rate Responses Between Active and Passive Recovery Modes Over a 15-Minute Recovery Period in Female Dancers After Kathak Dance.

Introduction: Dance is physically demanding and results in blood lactate (BL) accumulation and elevated Heart Rate (HR). Researchers recommend using either Active Recovery (AR; eg, low-to-moderate intensity-exercise) or Passive Recovery (PR; eg, complete rest) modes after activity. We compared BL and HR responses between AR or PR over a 15-minute recovery period following a Kathak dance. Methods: Twelve female dancers (31.0 ± 6.0 years; 161.5 ± 4.9 cm; 55.5 ± 5.8 kg) performed 2 dance testing sessions (Day 1 = AR, Day 2 = PR) 48 hours apart. Each session started with a 10-minute warm up followed by dancers performing four 2-minute stages of Kathak dance, with three 1-minute periods between stages where we recorded HR and their Rate of Perceived Exertion (RPE:scale = 6-20) to match the intensity of both sessions. Post-dance, we recorded dancers' BL and HR at 1, 3, 5, 10, and 15 minutes while they recovered via AR or PR. Separate 2(mode) × (time) Repeated-Measures-ANOVA followed by simple-main-effects testing and adjusted Bonferroni-pairwise-comparisons examined differences in BL and HR responses across modes and time(α = .05). Results: Dancers' HR and RPE were similar across sessions. No mode × time interaction existed in BL (F4,8 = 3.6, P = .06). BL levels were similar across modes (F1,2 = 0.5, P = .5). BL levels reduced over time (F4,8 = 6.0, P = .02), but Bonferroni-comparisons did not reveal any pairwise differences. In HR a significant mode*time interaction (F4,36 = 11.0, P = .01, η2 = .55) was observed. Both Active and Passive recovery modes achieved absolute HR levels by 15 minutes, with PR mode stabilizing within 5 minutes. Conclusions: Over a 15-minute recovery period after Kathak dance, dancers' BL and HR responses were similar across time in both AR and PR, with HR being higher in AR. Dancers' HR remained similar from 1 to 3 minute post dance recovery and then dropped over time. Thus, dancers can rest up to 3 minutes and still maintain the same elevated HR. Overall, dancers can choose either AR or PR as their recovery mode based on their individual preferences.

Resistance training in humans and mechanical overload in rodents do not elevate muscle protein lactylation.

Although several reports have hypothesized that exercise may increase skeletal muscle protein lactylation, empirical evidence in humans is lacking. Thus, we adopted a multi-faceted approach to examine if acute and subchronic resistance training (RT) altered skeletal muscle protein lactylation levels. In mice, we also sought to examine if surgical ablation-induced plantaris hypertrophy coincided with increases in muscle protein lactylation. To examine acute responses, participants' blood lactate concentrations were assessed before, during, and after eight sets of an exhaustive lower body RT bout (n = 10 trained college-aged men). Vastus lateralis biopsies were also taken before, 3-h post, and 6-h post-exercise to assess muscle protein lactylation. To identify training responses, another cohort of trained college-aged men (n = 14) partook in 6weeks of lower-body RT (3x/week) and biopsies were obtained before and following the intervention. Five-month-old C57BL/6 mice were subjected to 10 days of plantaris overload (OV, n = 8) or served as age-matched sham surgery controls (Sham, n = 8). Although acute resistance training significantly increased blood lactate responses ∼7.2-fold (p < 0.001), cytoplasmic and nuclear protein lactylation levels were not significantly altered at the post-exercise time points, and no putative lactylation-dependent mRNA was altered following exercise. Six weeks of RT did not alter cytoplasmic protein lactylation (p = 0.800) despite significantly increasing VL muscle size (+3.5%, p = 0.037), and again, no putative lactylation-dependent mRNA was significantly affected by training. Plantaris muscles were larger in OV versus Sham mice (+43.7%, p < 0.001). However, cytoplasmic protein lactylation was similar between groups (p = 0.369), and nuclear protein lactylation was significantly lower in OV versus Sham mice (p < 0.001). The current null findings, along with other recent null findings in the literature, challenge the thesis that lactate has an appreciable role in promoting skeletal muscle hypertrophy.

Fourteen-Days Spirulina Supplementation Increases Hemoglobin, but Does Not Provide Ergogenic Benefit in Recreationally Active Cyclists: A Double-Blinded Randomized Crossover Trial

Spirulina supplementation has been reported to increase hemoglobin concentration as well as a variety of cardiorespiratory and lactate-based performance parameters during maximal and submaximal states of exercise. This study investigates the efficacy of supplementing a 6 g/day dosage of spirulina for 14-days in recreationally active individuals, analyzing cardiorespiratory parameters during maximal and submaximal cycling as well as the potential mechanistic role of hemoglobin augmentation. 17 recreationally active individuals (Male = 14, Female = 3, Age 23 ± 5 years, V̇O2max 43.3 ± 8.6 ml/min·kg) ingested 6 g/day of spirulina or placebo for 14-days in a double-blinded randomized crossover study, with a 14-day washout period between trials. Participants completed a 20-min submaximal cycle at 40% maximal power output (WRmax), followed by a V̇O2max test. Hemoglobin (g/L), WRmax (watts), time to fatigue (seconds), heart rate (bpm), oxygen uptake (ml/min·kg), RER and blood lactate response (mmol/L) were measured and compared between conditions. Cardiorespiratory variables were recorded at 5-min intervals and lactate was measured at 10-min intervals during the submaximal exercise. There was a significant 3.4% increase in hemoglobin concentration after spirulina supplementation in comparison to placebo (150.4 ± 9.5 g/L Vs 145.6 ± 9.4 g/L, p = 0.047). No significant differences existed between either condition in both testing protocols for V̇O2max, WRmax, time to fatigue, heart rate, oxygen uptake, RER and blood lactate response (p > 0.05). 14-days of spirulina supplementation significantly improved hemoglobin concentration but did not lead to any considerable ergogenic improvements during maximal or submaximal exercise at a 6 g/day dosage in recreationally active individuals whilst cycling.

Blood Lactate Responses of Male and Female Players Across an International Rugby Sevens Tournament.

This study investigated within- and between-matches blood lactate (La-) responses across an international Rugby Sevens tournament (5 matches over 2d) in male and female players. 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 (30min). 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 30min, compared to PRE (+1.7 [1.4-2.0]mmol·L-1, P < .001), with ∼20% of values persisting >4mmol·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. Lactate concentrations above 10mmol·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.

Repetition Performance, Rating of Perceived Discomfort, and Blood Lactate Responses to Different Rest Interval Lengths in Single-Joint and Multijoint Lower-Body Exercise.

Rosa, A, Coleman, M, Haun, C, Grgic, J, and Schoenfeld, BJ. Repetition performance, rating of perceived discomfort, and blood lactate responses to different rest interval lengths in single-joint and multijoint lower-body exercise. J Strength Cond Res 37(7): 1350-1357, 2023-The purpose of this study was to examine the effects of different rest interval lengths (RILs) on repetition performance, rating of discomfort, and blood lactate responses during lower-body single-joint and multijoint exercises. This study used a counterbalanced design where each subject performed the Smith machine back squat (BS) and leg extension (LE) using 3 different RIL configurations (1, 2, and 3 minutes) in a randomized fashion. Data collection occurred over the span of 3 separate days. Volunteers were randomly allocated to perform the independent variables (RILs and exercises) in 1 of 12 potential configurations. The initial session was allotted for familiarization with the rating of discomfort scale and 10 repetition maximum testing. The other 2 sessions involved training with the different configurations of RIL length using both the BS and LE. Randomization ensured that the BS was performed first in one of the training sessions and the LE was performed first in the other session. Results indicated that longer RILs had a small positive effect on repetition performance, with longer rest durations allowing for more repetitions compared with shorter durations. The largest difference in repetition performance between RILs was observed between 1 minute and 2-3 minutes rest; there were trivial differences in repetition performance between 2 and 3 minutes rest for both the BS and LE. Blood lactate levels were slightly higher with longer RILs. Overall, BS showed greater increases in blood lactate compared with LE, and these differences were magnified over time. Exercise selection and RIL both influenced rating of discomfort, with LE producing less discomfort than BS and longer RILs reducing perceived discomfort. Our findings suggest that RIL influences the repetition performance, blood lactate, and rating of discomfort responses between single-joint and multijoint exercises.

Blood Lactate and Maximal Lactate Accumulation Rate at Three Sprint Swimming Distances in Highly Trained and Elite Swimmers

We examined the blood lactate response, in terms of the maximal post-exercise concentration (Lamax), time to reach Lamax, and maximal lactate accumulation rate (VLamax), to swimming sprints of 25, 35, and 50 m. A total of 14 highly trained and elite swimmers (8 male and 6 female), aged 14-32, completed the 3 sprints in their specialization stroke with 30 min of passive rest in between. The blood lactate was measured right before and continually (every minute) after each sprint to detect the Lamax. The VLamax, a potential index of anaerobic lactic power, was calculated. The blood lactate concentration, swimming speed, and VLamax differed between the sprints (p < 0.001). The Lamax was highest after 50 m (13.8 ± 2.6 mmol·L-1, mean ± SD throughout), while the swimming speed and VLamax were highest at 25 m (2.16 ± 0.25 m·s-1 and 0.75 ± 0.18 mmol·L-1·s-1). The lactate peaked approximately 2 min after all the sprints. The VLamax in each sprint correlated positively with the speed and with each other. In conclusion, the correlation of the swimming speed with the VLamax suggests that the VLamax is an index of anaerobic lactic power and that it is possible to improve performance by augmenting the VLamax through appropriate training. To accurately measure the Lamax and, hence, the VLamax, we recommend starting blood sampling one minute after exercise.

Variability in exercise tolerance and physiological responses to exercise prescribed relative to physiological thresholds and to maximum oxygen uptake.

What is the central question of this study? Does prescribing exercise intensity using physiological thresholds create a more homogeneous exercise stimulusthanusing traditional intensity anchors? What is the main finding and its importance? Prescribing exercise using physiological thresholds, notably critical power, reduced the variability in exercise tolerance and acute metabolic responses. At higher intensities, approaching or exceeding the transition from heavy to severe intensity exercise, the imprecision of using fixed % as an intensity anchor becomes amplified. The objective of this study was to determine whether the variability in exercise tolerance and physiological responses is lower when exercise is prescribed relative to physiological thresholds (THR) compared to traditional intensity anchors (TRAD). Ten individuals completed a series of maximal exercise tests and a series of moderate (MOD), heavy (HVY) and severe intensity (HIIT) exercise bouts prescribed using THR intensity anchors (critical power and gas exchange threshold) and TRAD intensity anchors (maximum oxygen uptake; ). There were no differences in exercise tolerance or acute response variability between MODTHR and MODTRAD . All individuals completed HVYTHR but only 30% completed HVYTRAD . Compared to HVYTHR , where work rates were all below critical power, work rates in HVYTRAD exceeded critical power in 70% of individuals. There was, however, no difference in acute response variability between HVYTHR and HVYTRAD . All individuals completed HIITTHR but only 20% completed HIITTRAD . The variability in peak (F=0.274) and average (F=0.318) blood lactate responses was lower in HIITTHR compared to HIITTRAD . The variability in W' depletion (the finite work capacity above critical power) after the final interval bout was lower in HIITTHR compared to HIITTRAD (F=0.305). Using physiological thresholds to prescribe exercise intensity reduced the heterogeneity in exercise tolerance and physiological responses to exercise spanning the boundary between the heavy and severe intensity domains. To increase the precision of exercise intensity prescription, it is recommended that, where possible, physiological thresholds are used in place of .

Analysis of blood lactate response in football small sided game among football players

Analysis of blood lactate response in football small sided game among football players

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

ABSTRACT Functional Threshold Power (FTP) has been considered a valid alternative to other performance markers that represent the upper boundary of the heavy intensity domain. However, such a claim has not been empirically examined from a physiological perspective.This study examined the blood lactate and VO2 response when exercising at and 15 W above the FTP (FTP+15W). Thirteen cyclists participated in the study. The VO2 was recorded continuously throughout FTP and FTP+15W, with blood lactate measured before the test, every 10 minutes and at task failure. Data were subsequently analysed using two-way ANOVA. The time to task failure at FTP and FTP+15W were 33.7 ± 7.6 and 22.0 ± 5.7 minutes (p < 0.001), respectively. The VO2peak was not attained when exercising at FTP+15W (VO2peak: 3.61 ± 0.81 vs FTP+15W 3.33 ± 0.68 L·min−1, p < 0.001). The VO2 stabilised during both intensities. However, the end test blood lactate corresponding to FTP and FTP+15W was significantly different (6.7 ± 2.1 mM vs 9.2 ± 2.9 mM; p < 0.05). The VO2 response corresponding to FTP and FTP+15W suggests that FTP should not be considered a threshold marker between heavy and severe intensity.

The Effects of Various Work-to-Rest Ratios During High-Intensity Intermittent Exercises on Uchi-Komi Performance and Postexercise Heart Rate and Blood Lactate in Judo Athletes.

Ceylan, B and Balci, SS. The effects of various work-to-rest ratios during high-intensity intermittent exercises on uchi-komi performance and postexercise heart rate and blood lactate in judo athletes. J Strength Cond Res 37(6): 1231-1236, 2023- Uchi-komi exercises are the most important component of judo training. This study aimed to investigate the effect of different rest intervals during high-intensity intermittent uchi-komi exercises on total technique repetitions and physiological load in judo athletes. Twenty-two male judo athletes (mean age 19.0 ± 1.2 years, judo experience 7.6 ± 22.7 years) voluntarily participated in this study. Athletes' body composition and judo-specific performance were determined. The athletes randomly performed 20 seconds × 8 sets of high-intensity intermittent exercise using ippon-seoi-nage technique with 1:1/2, 1:1, 1:2, and 1:3 work-to-rest ratios on separate days. Before and 1, 7, 15, and 30 minutes after each exercise, athletes' heart rate (HR) and blood lactate were determined. The number of repetitions differed according to rest durations, when the rest duration decreased, the number of the repetitions decreased ( F21, 441 = 7.09, p < 0.001). Blood lactate responses were similar during the exercises with different rest intervals ( F3,63 = 2.15, p = 0.10). The shorter the rest duration, the higher the HR ( F3,63 = 6.81, p < 0.001). The current study proposed that 1:2 and 1:3 work-to-rest ratios at high-intensity intermittent uchi-komi exercise are the most appropriate intervals to ensure a high number of technique repetitions and the continuity of the training.

Acute Effects of Heavy Strength Training on Mechanical, Hemodynamic, Metabolic, and Psychophysiological Parameters in Young Adult Males.

This study analyzed the acute effects of heavy strength training on mechanical, hemodynamic, metabolic, and psychophysiological responses in adult males. Thirteen recreational level males (23.3 ± 1.5 years) randomly performed two heavy strength training sessions (3 sets of 8 repetitions at 80% of one repetition maximum [1RM]) using the bench press (HST-BP) or full squat (HST-FS)). The repetition velocity was recorded in both sessions. Moreover, before and after the sessions, the velocity attained against the ~1.00 m·s−1 load (V1Load) in the HST-BP, countermovement jump (CMJ) height in the HST-FS, blood pressure, heart rate, blood lactate, and psychophysiological responses (OMNI Perceived Exertion Scale for Resistance Exercise) were measured. There were differences between exercises in the number of repetitions performed in the first and third sets (both <8 repetitions). The velocity loss was higher in the HST-BP than in the HST-FS (50.8 ± 10.0% vs. 30.7 ± 9.5%; p < 0.001). However, the mechanical fatigue (V1Load vs. CMJ height) and the psychophysiological response did not differ between sessions (p > 0.05). The HST-FS caused higher blood pressure and heart rate responses than the HST-BP (p < 0.001 and p = 0.02, respectively) and greater blood lactate changes from pre-training to post-set 1 (p < 0.05). These results showed that the number of maximal repetitions performed in both sessions was lower than the target number and decreased across sets. Moreover, the HST-BP caused a higher velocity loss than the HST-FS. Finally, the HST-FS elicited higher hemodynamic and metabolic demand than the HST-BP.

Sex-related differences in perceptual indices, serum cortisol and blood lactate responses to endurance exertion in competitive male and female athletes in a field setting

Background: Boxing requires very high aerobic fitness from male and female practitioners, therefore, endurance exercises play an important role in the preparation to competition. One of the way for rating of the state of demanded physical adaptation is monitoring of biological responses to endurance training units. The aim of the study was to examine psycho-hormonal responses to a 10km cross-country run in male and female boxers. Material and methods: Twenty-four amateur adult boxers, 12 women and 12 men, of various weight categories, excluding heavyweight athletes, performed field a 10km run. Capillary blood was sampled in the morning at 8:00, 5 minutes prior to the run (11:00 am), and within 5 minutes after exercise. Plasma cortisol concentration (C) was determined using a commercial ELISA kit (IBL, GERMANY). Post-exercise blood lactate was determined with a Lactate Scout analyzer. Pre-run anticipatory stress (AS) was estimated on a numerical scale of 1 to 10 points, with the same tool used to measure the rating of perceived exertion (RPE). Results: Morning plasma cortisol levels in females (54082 nM) and males (52073 nM) did not differ significantly but the pre-and post-run levels were higher in females. Furthermore, males rather than females showed lower pre-exercise compared to post-exercise C levels, meaning that blood lactate level was significantly higher in males (6.31.1 mM) compared to that in females (5.40.7 mM). There were no significant differences between the sexes for AS and RPE. However, both perceptual parameters were slightly higher in females. Conclusion: Based on blood cortisol measurements and perceptual parameters it can be concluded that the psychophysiological cost of exercise is higher in female athletes, even in the case of non-competitive exercise.

Acute Physiological and Perceptual Responses to Rest Redistribution With Heavier Loads in Resistance-Trained Men.

Chae, S, Hill, DW, Bailey, CA, Moses, SA, McMullen, SM, and Vingren, JL. Acute physiological and perceptual responses to rest redistribution with heavier loads in resistance-trained men. J Strength Cond Res 37(5): 994-1000, 2023-The purpose of this study was to explore the effect of rest redistribution with heavier loads (RR + L) on physiological and perceptual responses in resistance-trained men. Eight men who had back squat (BS) 1 repetition maximum (1RM) to body mass ratio; 1.8 ± 0.2 completed 2 BS exercise sessions in a counterbalanced and a randomized order; RR + L: 4 sets of (2 × 5) repetitions with 90-second interset rest and 30-second intraset rest using 75% BS 1RM and traditional sets (TS): 4 sets of 10 repetitions with 120-second interset rest using 70% BS 1RM. Blood samples were collected before exercise, immediately post exercise, and 5, 15, and 30 minutes post exercise for the analysis of growth hormone (GH), total testosterone (TT), cortisol (C), and blood lactate (BL), whereas rating of perceived exertion (RPE) and heart rate (HR) were measured immediately after each set of the BS exercise. While neither main effect of condition nor interaction existed, there was a significant ( p < 0.05) main effect of time point (and set) for GH, TT, C, BL, RPE, and HR. Volume load was greater for RR + L compared with TS (4,074.9 ± 786.7 kg vs. 3,796.3 ± 714.8 kg). In conclusion, RR + L increases volume load by approximately 7% but does not seem to influence GH ( g = -0.15), TT ( g = -0.09), BL ( g = -0.22), RPE ( g = 0.14), and HR ( g = -0.08) responses. Practitioners may consider using RR + L to increase volume load without increasing acute fatigue responses.

Heart rate and blood lactate responses during the volleyball match

This study aimed to examine the heart rate and blood lactate responses of female volleyball players during the match according to the player positions. A total of 24 senior female volleyball players (middle blocker (n = 6), setter (n = 6), spiker (n = 6), and libero (n = 6)) were monitored for heart rate and blood lactate before, during and after a volleyball match. The mean heart rate and blood lactate level of volleyball players were determined 117.2 ± 13.9 bpm, 2.7 ± 1.2 mmol/L during the match. Heart rate was statistically different between all playing positions except middle blockers vs. spikers (p < 0.05). The blood lactate levels between the groups were not statistically different. The setters have the lowest heart rate and the libero players have the highest during the match. All subjects have a heart rate 50–60% and below 50% of their heart rate maximum during more than half of the match duration. These current results can be used by coaches to determine a specific training load based on the heart rate and blood lactate differences between playing positions.

Performance and Submaximal Adaptations to Additional Speed-Endurance Training Vs. Continuous Moderate-Intensity Aerobic Training in Male Endurance Athletes.

We examined performance and submaximal adaptations to additional treadmill-based speed-endurance training (SET) vs. continuous moderate-intensity aerobic training (MIT) twice / week. Twenty-two male endurance athletes were tested before and after 10-week SET (6-12 × 30-s sprints separated by 3-min rest intervals) and MIT (2040 min continuous running at ~70% maximal oxygen uptake [V̇O2max]). The SET group attained greater acute heart rate (HR) and blood lactate responses than the MIT group (d = 0.86–0.91). The SET group improved performance in a time-to-exhaustion trial, V̇O2max, and lactate threshold (d = 0.50–0.73), whereas no training-induced changes were observed in the MIT group. Additionally, the SET group reduced oxygen uptake, mean HR and improved running economy (d = 0.53–0.86) during running at 10 and 12 km·h-1. Additional SET imposes greater physiological demands than MIT resulting in superior performance adaptations and reduced energy cost in endurance athletes.

Effects Of Transdermal Sodium Bicarbonate Lotion On High-intensity Cycling Performance

Pre-exercise oral ingestion of sodium bicarbonate may lead to improved high-intensity exercise performance in trained individuals. However, this practice often causes gastrointestinal distress, which can mitigate the ergogenic benefits. An alternative method of administration involves the delivery of sodium bicarbonate through applying lotion to the surface of the skin surrounding the working muscles. However, few studies have examined the ergogenic benefits of this practice. PURPOSE: To examine the effects of pre-exercise application of a sodium bicarbonate lotion (SBL) on performance during a series of intermittent high-intensity cycling bouts compared to a placebo (PLA). METHODS: In a randomized cross-over fashion, 7 trained cyclists completed a one-hour cycling performance test on a stationary trainer using their personal road bikes on two separate occasions. This protocol consisted series of maximal 5-second (neuromuscular, NM), 5-minute (maximal aerobic, MAP), 20-minute (functional threshold, FTP), and 1-minute (anaerobic capacity, AC) efforts separated by recovery. Performance was determined by the mean power output during each effort. Thirty minutes prior, subjects applied 0.4 g/kg-bw of either SBL or PLA to the quadriceps, hamstrings, and gastrocnemius. Capillary samples were collected at 1-minute and 3-minutes following the MAP, FTP, and AC tests to measure blood lactate. Differences in power output and lactate responses between conditions were tested using Wilcoxon signed-rank tests. RESULTS: There were no differences in power output during the any of the efforts between conditions. In the SBL condition, participants had higher blood lactate concentrations one-minute following the MAP test compared to PLA (p = 0.01, mean dif. = 4.3 mmol/L). CONCLUSION: Our findings suggest that pre-exercise application of SBL did not influence performance in trained cyclists. The elevated blood lactate response to the MAP effort in SBL could indicate enhanced cellular buffering and lactate clearance. Practically, this suggests that SBL could be beneficial prior to shorter time-trials or intervals performed near maximal aerobic capacity. Once the target sample of 16 cyclists have completed the study, we can provide further insight on the ergogenic effects of SBL application in this population.