Blood Lactate Responses Research Articles

Effects of Static Apnea Training on Pulmonary Function, Blood Lactate Response and Exercise Performance of Elite Swimmers

PURPOSE: The purpose of this study was to investigate the effects of training on improvement in pulmonary function and swimming performance by implementing static apnea training for 4 weeks in elite male swimmers.METHODS: Twenty elite swimmers were divided into two groups, the apnea training group (Apnea, n=11) and the control group (control, n=9). Each swimmer received identical swimming and ground training for 4 weeks. The apnea group performed 10 sets of breathholding a day additionally. In all participants, the pulmonary function tests [forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1)] were evaluated. The blood lactate level was also measured after each swimmer completed swimming 5 laps.RESULTS: After 4 weeks of static apnea training, the FVC of the apnea group significantly increased (p=.008), whereas the FEV1/FVC ratio did not change. Breath-holding time increased significantly after apnea training (p=.001). There were no significant differences between the groups in the 50-m time trial records. However, the apnea group show a significant difference at the 4th (p=.013) and 5th trial (p=.023). The blood lactate levels after the 50-m trial was not significantly different between the groups, but the levels in the apnea group showed a significant increase in the results of the 2nd trial compared to those before apnea training (p=.008).CONCLUSIONS: The results of our study reveal that static apnea training improves pulmonary function, in contrast to a few time trials that show varying differences in swimming records and blood lactate levels. These results warrant a review of the training protocol to evaluate the effect on performance. In conclusion, static apnea training is a potential exercise that can improve performance in competitive sports.

Alterations in acid\u2013base balance and high-intensity exercise performance after short-term and long-term exposure to acute normobaric hypoxic conditions

This investigation assessed the course of renal compensation of hypoxia-induced respiratory alkalosis by elimination of bicarbonate ions and impairments in anaerobic exercise after different durations of hypoxic exposure. Study A: 16 participants underwent a resting 12-h exposure to normobaric hypoxia (3,000 m). Blood gas analysis was assessed hourly. While blood pH was significantly increased, PO2, PCO2, and SaO2 were decreased within the first hour of hypoxia, and changes remained consistent. A substantial reduction in [HCO3−] levels was observed after 12 h of hypoxic exposure (− 1.35 ± 0.29 mmol/L, p ≤ 0.05). Study B: 24 participants performed in a randomized, cross-over trial portable tethered sprint running (PTSR) tests under normoxia and after either 1 h (n = 12) or 12 h (n = 12) of normobaric hypoxia (3,000 m). No differences occurred for PTSR-related performance parameters, but the reduction in blood lactate levels was greater after 12 h compared with 1 h (− 1.9 ± 2.2 vs 0.0 ± 2.3 mmol/L, p ≤ 0.05). These results indicate uncompensated respiratory alkalosis after 12 h of hypoxia and similar impairment of high-intensity exercise after 1 and 12 h of hypoxic exposure, despite a greater reduction in blood lactate responses after 12 h compared with 1 h of hypoxic exposure.

The Use of Acute Exercise Interventions as Game Day Priming Strategies to Improve Physical Performance and Athlete Readiness in Team-Sport Athletes: A Systematic Review.

The use of exercise as a priming strategy to enhance sport performance is becoming increasingly popular in professional sports and as an area of research interest. Early research suggests that the acute physiological responses to exercise can positively influence performance for up to 48h. There is yet to be a comprehensive review of exercise strategies which could be implemented specifically on the day of competition. The aim of this systematic review was to provide a synthesis of research investigating acute exercise interventions as game day priming strategies for team-sport athletes to improve physical performance and athlete readiness when implemented in the 1-12h prior to competition. A literature search of SPORTDiscus, PubMed and Cochrane Central Register for Controlled Trials was conducted. A total of 6428 studies were retrieved and assessed against the following inclusion criteria: (1) randomised controlled trials and non-randomised comparative studies with reported pre-post intervention outcomes; (2) exercise interventions were applied 1-12h prior to the assessment of outcome measures. Studies were excluded if they used nutrition, supplementation, pre-heating, pre-cooling, stretching, massage or vibration training as the priming strategies, or if interventions were performed at altitude or in hypoxic environments. Studies were assessed for methodological quality at the study level using the Physiotherapy Evidence Database (PEDro) scale. Twenty-nine studies satisfied the eligibility criteria and were included in this review. Studies were categorised as resistance training; cycling; running; and other strategies. Resistance training using heavy loads at low volumes increased strength and power measures following a 4-6h recovery, with limited improvements observed following shorter (1-3h) and longer (6-12h) recovery periods. Running-based sprint priming led to improvements in subsequent sprint and repeat sprint performance following a 5-6h recovery, whereas cycling improved counter-movement jump height in a single study only. No significant differences were reported in any performance measures following endurance-based running or cycling strategies. Physiological markers, such a hormone and blood lactate responses, showed mixed results between studies. High-intensity low-volume resistance training leads to a greater physiological and performance response than high-volume resistance training. Maximal running sprints may be more effective than maximal cycling sprints due to an increased physiological demand; however, loading protocols must also be considered in conjunction with exercise volume and movement specificity to achieve a beneficial response for subsequent performance. There is limited evidence to suggest endurance cycling or running exercise is beneficial as a priming strategy.

Effects of surgical and FFP2/N95 face masks on cardiopulmonary exercise capacity

BackgroundDue to the SARS-CoV2 pandemic, medical face masks are widely recommended for a large number of individuals and long durations. The effect of wearing a surgical and a FFP2/N95 face mask on cardiopulmonary exercise capacity has not been systematically reported.MethodsThis prospective cross-over study quantitated the effects of wearing no mask (nm), a surgical mask (sm) and a FFP2/N95 mask (ffpm) in 12 healthy males (age 38.1 ± 6.2 years, BMI 24.5 ± 2.0 kg/m2). The 36 tests were performed in randomized order. The cardiopulmonary and metabolic responses were monitored by ergo-spirometry and impedance cardiography. Ten domains of comfort/discomfort of wearing a mask were assessed by questionnaire.ResultsThe pulmonary function parameters were significantly lower with mask (forced expiratory volume: 5.6 ± 1.0 vs 5.3 ± 0.8 vs 6.1 ± 1.0 l/s with sm, ffpm and nm, respectively; p = 0.001; peak expiratory flow: 8.7 ± 1.4 vs 7.5 ± 1.1 vs 9.7 ± 1.6 l/s; p < 0.001). The maximum power was 269 ± 45, 263 ± 42 and 277 ± 46 W with sm, ffpm and nm, respectively; p = 0.002; the ventilation was significantly reduced with both face masks (131 ± 28 vs 114 ± 23 vs 99 ± 19 l/m; p < 0.001). Peak blood lactate response was reduced with mask. Cardiac output was similar with and without mask. Participants reported consistent and marked discomfort wearing the masks, especially ffpm.ConclusionVentilation, cardiopulmonary exercise capacity and comfort are reduced by surgical masks and highly impaired by FFP2/N95 face masks in healthy individuals. These data are important for recommendations on wearing face masks at work or during physical exercise.

The Effects Of One-week Exogenous Ketone Consumption On Short Distance Time Trial Running Performance

Currently, there is equivocal knowledge concerning the effects of ketone salt supplementation on short distance running time trial (TT) performance in well-trained subjects. PURPOSE: To determine the effects of one-week exogenous ketone salt supplementation on 800m running TT performance during non-fatigued and pre-exhaustive states in endurance-trained subjects. METHODS: In a randomized, double-blind, placebo-controlled study, endurance-trained male and female participants were allocated to one of the following treatment groups for 8 days following an initial familiarization visit: Ketone supplementation (KET) (n=16) or placebo control (CON) (n=16). Subjects underwent two consecutive 800m TT before and after the 8-day treatment period on a self-propelled, non-motorized treadmill. Time-to-completion of the first (TT1) and second (TT2) TTs, the average time-to-completion across both TTs, and blood lactate response during the TTs were measured pre- and post-treatment. A mixed factorial ANOVA was used for data analysis. RESULTS: KET alone exhibited a significant increase in blood β-hydroxybutyrate from pre-post-treatment (p<0.05). A group x time interaction was only detected for TT2 performance (p<0.05) but not TT1. There was no pre- to post-treatment change in TT1 performance in either group. CON demonstrated no change in TT2 performance from pre- to post-treatment; however, KET improved TT2 performance as reflected by a 3.7% faster time-to-completion from pre- to post-treatment (p<0.05). When examining the average time-to-completion across both TTs, there was a significant group x time interaction (p=0.04). CON showed no change while KET demonstrated a faster average time-to-completion from pre- to post-treatment (p<0.05). Blood lactate response to TTs decreased (p<0.05) in KET but not CON. CONCLUSIONS: In endurance-trained subjects, ketone salt supplementation does not appear to affect short-distance running TT performance in a non-fatigued state reflective of competition scenarios. However, ergogenic effects may be observed in high-intensity exercise when some level of exhaustion or energy substrate depletion is experienced prior, such as during training or prolonged, intermittently high-intensity sporting bouts.

Heart rate and blood lactate responses during the cross-country test of 2-star to 5-star eventing competitions

The objective of this retrospective study was to evaluate the physiological demands of cross-country competitions at different levels. Heart rates (HR) and post exercise blood lactate concentrations (LAC) measured between 2010 and 2019 in response to 1,463 cross-country competitions (437 at 2-star, 703 at 3-star, 313 at 4-star and 10 at 5-star level) in 294 horses were analysed. The effect of competition level, mean velocity, height profile, total distance, number of jumping efforts, climate, age, sex, percentage of Thoroughbred blood and performance level on HR, LAC, HR recovery and LAC disappearance rates was evaluated by Linear Mixed Effects Models. Mean HR and LAC significantly increased from 2-star to 4-star level (P&lt;0.001). Each 30 m/min increase in mean velocity was associated with a 3 beats/min increase in HR (P&lt;0.001) and a 41% increase in LAC (P&lt;0.001) and each 30 m increase in cumulative elevation with a 2 beats/min increase in HR (P&lt;0.001) and a 32% increase in LAC (P&lt;0.001). Each 20 m increase in mean distance per jumping effort was associated with a 1 beat/min decrease in HR (P&lt;0.01) and a 13% decrease in LAC (P&lt;0.001). Compared to Warmbloods, horses with 75% Thoroughbred blood had 4 beats/min lower HRs (P&lt;0.05) and 34% lower LAC values (P&lt;0.001). Each 5 years increase in age was associated with a 4 beats/min decrease in HR (P&lt;0.001, only in mares) and an 11% decrease in LAC (P&lt;0.01). The HRs during the first 3 minutes of recovery were higher at warmer and more humid conditions (P&lt;0.05). The rate of LAC disappearance was higher in horses with higher percentages of Thoroughbred blood (P&lt;0.05).

Does caffeine affect the response of blood lactate to desensitization activities in young swimmers?

Does caffeine affect the response of blood lactate to desensitization activities in young swimmers?

Effect of β-Alanine Supplementation on Repeated Sprint Ability and Responses of Blood Lactate and Bicarbonate in Male Soccer Players

Effect of β-Alanine Supplementation on Repeated Sprint Ability and Responses of Blood Lactate and Bicarbonate in Male Soccer Players

Game format alters the physiological and activity demands encountered during small-sided football games in recreational players

BackgroundConditioning in the form of football small-sided games (SSG) is being increasingly utilized as a health-promoting and performance-enhancing activity. ObjectiveThe aim of this study was to quantify and compare the physiological responses and activity demands encountered during 3-a-side, 4-a-side, and 5-a-side football SSG in recreational players. MethodHeart rate, blood lactate (BLa), rating of perceived exertion (RPE) and activity demands were measured across 2 × 20-min football sessions played on a 40 × 20-m pitch in 12 recreationally active college students. Data were collected over a period of two weeks using a repeated-measures crossover design. ResultsMean heart rate was higher (moderate) during 5-a-side than 4-a-side (p = 0.02) and 3-a-side SSG (p < 0.001). BLa tended to be higher (small) in 3-a-side compared to 4-a-side (p = 0.12) and 5-a-side SSG (p = 0.46). The total distance covered was lower (large) during 5-a-side than 4-a-side SSG (p = 0.02), while the total number of accelerations (p = 0.01) and decelerations (p = 0.02) were higher (large) during 5-a-side than 4-a-side SSG. ConclusionThese data suggest: 1) 5-a-side SSG require a greater intermittent workload and exacerbated HR responses; 2) 4-a-side SSG require more sustained activity (distance); and 3) 3-a-side SSG result in higher BLa compared to other SSG formats. The observed intermittent workload and exacerbated HR response in 5-a-side SSG were likely due to greater turnover rates with more frequent interceptions. Sustained activity in 4-a-side SSG might be underpinned by format-specific structures permitting optimal team work, while isolated guarding of players in 3-a-side SSG may have exacerbated BLa responses.

Warming Up Before a 20-Minute Endurance Effort: Is It Really Worth It?

To analyze the effects of different warm-up protocols on endurance-cycling performance from an integrative perspective (by assessing perceptual, neuromuscular, physiological, and metabolic variables). Following a randomized crossover design, 15 male cyclists (35 [9]y; peak oxygen uptake [VO2peak] 66.4 [6.8]mL·kg-1·min-1) performed a 20-minute cycling time trial (TT) preceded by no warm-up, a standard warm-up (10min at 60% of VO2peak), or a warm-up that was intended to induce potentiation postactivation (PAP warm-up; 5min at 60% of VO2peak followed by three 10-s all-out sprints). Study outcomes were jumping ability and heart-rate variability (both assessed at baseline and before the TT), TT performance (mean power output), and perceptual (rating of perceived exertion) and physiological (oxygen uptake, muscle oxygenation, heart-rate variability, blood lactate, and thigh skin temperature) responses during and after the TT. Both standard and PAP warm-up (9.7% [4.7%] and 12.9% [6.5%], respectively, P < .001), but not no warm-up (-0.9% [4.8%], P = .074), increased jumping ability and decreased heart-rate variability (-7.9% [14.2%], P = .027; -20.3% [24.7%], P = .006; and -1.7% [10.5%], P = .366). Participants started the TT (minutes 0-3) at a higher power output and oxygen uptake after PAP warm-up compared with the other 2 protocols (P < .05), but no between-conditions differences were found overall for the remainder of outcomes (P > .05). Compared with no warm-up, warming up enhanced jumping performance and sympathetic modulation before the TT, and the inclusion of brief sprints resulted in a higher initial power output during the TT. However, no warm-up benefits were found for overall TT performance or for perceptual or physiological responses during the TT.

Oxygen Uptake, Heart Rate, and Lactate Responses for Continuous Forward Running and Stop-and-Go Running With and Without Directional Changes.

Bekraoui, N, Boussaidi, L, Cazorla, G, and Léger, L. Oxygen uptake, heart rate, and lactate responses for continuous forward running and stop-and-go running with and without directional changes. J Strength Cond Res 34(3): 699-707, 2020-The purpose of this study is to measure and quantify the differences for the gross oxygen uptake (V[Combining Dot Above]O2), heart rate (HR), and blood lactate ([LA]) responses to various modes of in-line running. Twelve healthy participants did an indirect continuous multistage field test to determine the maximal aerobic speed (MAS) before randomly performing in separate sessions 1 of the 3 running protocols at 3 intensities (60, 70, and 80% MAS) (a) in-line continuous running (IR), (b) fractioned running (FR) with stop and go every 20 m, and (c) 20-m shuttle run (SR). V[Combining Dot Above]O2 varied between 34.2 ± 2.5 and 54.6 ± 5.4 ml·kg·min, HR between 141 ± 14 and 184 ± 9 b·min, and [LA] between 4.2 ± 0.8 and 6.6 ± 0.9 mmol·L. In-line continuous running V[Combining Dot Above]O2 was lower than those of SR and FR at all intensities (p < 0.05). However, SR V[Combining Dot Above]O2 were higher than those of FR at 80% MAS only. Heart rate was similar in SR and FR but lower in IR at all intensities (p < 0.05). No significant differences were recorded in [LA]. Because only V[Combining Dot Above]O2 was affected by the introduction of a 180° angle directional change (SR vs. FR) at 80% MAS, the use of HR to assess such activities at such intensities will result in underestimating workloads. This study offers new insights into V[Combining Dot Above]O2, HR, and [LA] associated with accelerations while running with and without directional changes at submaximal speeds.

Acute effects of small-sided games combined with running drills on internal and external loads in young soccer players.

The purpose of this study was to compare the effects of regular small-sided games (SSGreg) and SSGs combined with running drills (SSGcom) on players’ internal and external loads. Eighteen young male soccer players (average age: 18.2 ± 0.5 years) participated in 3 vs. 3 and 4 vs. 4 games, under both SSGreg and SSGcom conditions. SSGreg bouts were played for 4 minutes without additional running drills, while SSGcom bouts consisted of 3 min 30 s SSG and 15 s running before and after the bout, making the duration of each bout 4 minutes. During all SSGs, measurements of heart rate (HR) responses as well as distances covered in four different speed zones – walking (WLK), low-intensity (LIR), moderate-intensity (MIR) and high-intensity running (HIR) – were recorded. Technical characteristics were monitored during the SSGs, and the rating of perceived exertion (RPE) and blood lactate (La-) responses were determined at the end of each SSG condition. Compared to the SSGreg in both 3 vs. 3 and 4 vs. 4 formats, the SSGcom condition resulted in higher La- and RPE responses (p < 0.05), greater distance covered at MIR and HIR speeds and greater total distance (p < 0.05). The results of this study show that replacing 30 s within the 4-min bouts of SSGs (both 3- and 4-a-side) by 2 x 15 s of running drills is effective in increasing internal (La- and RPE) and external loads (MIR and HIR) without a significant decrease in total passes and successful passes in young soccer players.

New On-Water Test for the Assessment of Blood Lactate Response to Exercise in Elite Kayakers.

Lactate thresholds are physiological parameters used to train athletes and monitor performance or training. Currently, the assessment of lactate thresholds in kayakers is performed in a laboratory setting utilizing specific ergometers; however, laboratory tests differ from on-water evaluation for several reasons. The aim of this study was to assess reliability and validity of a new on-water incremental test for the assessment of blood lactate response to exercise in flat-water kayakers. Maximal lactate steady state test (MLSS) was used as criterion measurement. Eleven junior (16.5 ± 1.9 yr) élite flat-water kayakers performed: i) an incremental cardiopulmonary test up to voluntary exhaustion on a stationary kayak ergometer to determine peak oxygen uptake; ii) an on-water 1000-m distance trial (T1000) to record best performance time and average speed (S1000); iii) two repetitions of on-water incremental kayaking test (WIK test); iv) several repetitions of on-water constant speed tests to determine MLSS. Speed, HR, and blood lactate concentrations were determined during on-water tests. The best performance time in T1000 was 262 ± 13 s, corresponding to an S1000 of 3.82 ± 0.19 m·s. Lactate threshold determined by modified Dmax method (LTDmod) during WIK test was 2.78 ± 1.02 mmol·L and the corresponding speed (SLT) was 3.34 ± 0.16 m·s. Test-retest reliability, calculated on SLT, was strong (ICC = 0.95 and r = 0.93). MLSS test corresponded to 3.06 ± 0.68 mmol·L and was reached at a speed (SMLSS) of 3.36 ± 0.14 m·s. Correlation coefficient between SLT and SMLSS was 0.90 (P = 0.0001). Interestingly, a significant correlation (r = 0.96, P < 0.0001) was observed between SLT and S1000. The WIK test showed good reliability and validity for the assessment of speed corresponding to LTDmod in flat-water kayakers and it could be a useful tool to monitor athletic performance. The speed value at LTDmod nicely predicted performance on 1000 m.

Active Video Games Versus Traditional Exercises: Energy Expenditure and Blood Lactate Responses

ABSTRACTPurpose: The current study aimed to investigate the exercise intensity and exercise characteristics of active video games (AVGs) by measuring various physiological responses, and to test whether AVGs can be used in components of training in sports branches. Methods: Twenty-two male athletes with good aerobic fitness level (age = 20.6 ± 2.2 years; maximum oxygen consumption (VO2max) = 52.2 ± 3.5 ml.kg−1.min−1) visited the laboratory three times (D1, D2, and D3). After taking measurements during rest, the VO2max was assessed (D1). Traditional brisk walking and running exercises were performed consecutively (D2), and AVGs—dancing and fighting—were performed at random (D3); each exercise session lasted 20 minutes, and for each experiment session oxygen consumption (VO2), heart rate (HR) were recorded, VO2max%, metabolic equivalent (MET), and energy expenditure (EE) were calculated. Results: No significant differences were found between AVG-dancing and brisk walking (p > .05) for VO2 (25.96 ± 3.3 vs. 24.39 ± 2.3 ml.kg−1.min−1), HR (137.02 ± 20.15 vs. 125.61 ± 6.49 beats.min−1) VO2max% (49.99 ± 7.00 vs. 46.84 ± 4.06), MET (7.49 ± 0.94 vs. 6.96 ± 0.65), and EE (181.19 ± 27.65 vs. 171.21 ± 22.51 Kcal). Additionally, no significant differences were found between AVG-fighting and running (p > .05) for VO2 (33.96 ± 5.88 vs. 33.13 ± 2.52 ml.kg−1.min−1), HR (155.66 ± 15.05 vs. 153.30 ± 6.83 beats.min−1), VO2max% (65.05 ± 9.76 vs. 63.60 ± 3.51), MET (9.70 ± 1.68 vs. 9.47 ± 0.72), and EE (236.75 ± 37.20 vs. 232.70 ± 27.06). Conclusions: AVG-dancing and fighting were defined as moderate (MET>7) and high (MET>9) intensity intermittent exercises, respectively. Consequently, AVGs can be a part of training for athletes; as a block, modified block or a traditional training cycle involving enjoyable alternative exercises, especially when the appropriate AVGs are chosen.

Four Days of Blueberry Powder Supplementation Lowers the Blood Lactate Response to Running But Has No Effect on Time-Trial Performance.

Blueberries are abundant with anthocyanins possessing antioxidant and anti-inflammatory properties. As these properties combat fatigue and promote recovery, blueberry supplementation may enhance performance and recovery. Thus, the objectives were to examine the effects of two blueberry supplementation protocols on running performance, physiological responses, and short-term recovery. Using a randomized, double-blind, placebo (PLA)-controlled crossover design, 14 runners completed an 8-km time trial (TT) after supplementation with 4 days of blueberries (4DAY), 4 days of a PLA, or 2 days of placebo followed by 2 days of blueberries (2DAY). Heart rate and ratings of perceived exertion were monitored during the TT. Blood lactate, vertical jump, reactive strength index, and salivary markers were assessed before and after. No significant differences were observed for time to complete the TT (PLA: 3,010 ± 459s; 2DAY: 3,014 ± 488s; 4DAY: 3,011 ± 423s), heart rate, ratings of perceived exertion, or any of the salivary markers. An interaction effect (p = .027) was observed for blood lactate, with lower post-TT concentrations in 4DAY (5.4 ± 2.0mmol/L) than PLA (6.6 ± 2.5mmol/L; p = .038) and 2DAY (7.4 ± 3.4mmol/L; p = .034). Post-TT decreases in vertical jump height were not different, whereas the decline in reactive strength index was less following 4DAY (-6.1% ± 13.5%) than the other conditions (PLA: -12.6% ± 10.1%; 2DAY: -11.6% ± 11.5%; p = .038). Two days of supplementation did not influence performance or physiological stress. Although 4 days of supplementation did not alter performance, it blunted the increase in blood lactate, perhaps reflecting altered lactate production and/or clearance, and offset the decrease in dynamic muscle function post-TT, as indicated by the reactive strength index differences.

Blood Lactate Concentration Is Not Related to the Increase in Cardiorespiratory Fitness Induced by High Intensity Interval Training.

Background: There is individual responsiveness to exercise training as not all individuals experience increases in maximal oxygen uptake (VO2max), which does not benefit health status considering the association between VO2max and mortality. Approximately 50% of the training response is genetic, with the other 50% accounted for by variations in dietary intake, sleep, recovery, and the metabolic stress of training. This study examined if the blood lactate (BLa) response to high intensity interval training (HIIT) as well as habitual dietary intake and sleep duration are associated with the resultant change in VO2max (ΔVO2max). Methods: Fourteen individuals (age and VO2max = 27 ± 8 years and 38 ± 4 mL/kg/min, respectively) performed nine sessions of HIIT at 130% ventilatory threshold. BLa was measured during the first and last session of training. In addition, sleep duration and energy intake were assessed. Results: Data showed that VO2max increased with HIIT (p = 0.007). No associations occurred between ΔVO2max and BLa (r = 0.44, p = 0.10), energy intake (r = 0.38, p = 0.18), or sleep duration (r = 0.14, p = 0.62). However, there was a significant association between training heart rate (HR) and ΔVO2max (r = 0.62, p = 0.02). Conclusions: When HIIT is prescribed according to a metabolic threshold, energy intake, sleep status, and BLa do not predict ΔVO2max, yet the HR response to training is associated with the ΔVO2max.

Correlation of competition performance with heart rate and blood lactate response during interval training sessions in eventing horses

Objective performance monitoring in eventing horses is rare as the implementation of standardised exercise tests is commonly perceived to interfere with the daily training routine. The validity of performance parameters derived from GPS data, heart rate (HR) and post exercise blood lactate concentration (LAC) measured during usual training sessions should therefore be evaluated. Velocity (V), HR and post exercise LAC recorded during 172 interval training sessions in 30 horses were retrospectively analysed. Linear regression of HR, averaged over retrospectively defined speed ranges, was used to calculate the V at HRs of 150 (V150) and 200 (V200) beats/min. A single exponential regression model, fitted to LAC in relation to HR values from the whole group of horses, was used to predict LAC for each horse’s individual HR value and to calculate the difference between measured and predicted LAC (LACdiff). Recovery HRs were derived from bi-exponential regression of HR decrease after exercise. Results were compared between different stages of training in the same horses and between horses categorised as superior (SP) and average performer (AP) according to their competition performance. V150 and V200 significantly increased with progressing training. SP had higher V150 and V200 values, lower LACdiff values and lower HRs after 1 min of recovery (HRR60s) than AP. Competition performance was positively correlated to V150 and V200 but negatively correlated to LACdiff and HRR60s. Regular monitoring of HR and LAC in response to interval training provided valuable indicators of performance. The results of this study may contribute to an increased applicability of routine performance monitoring in eventing horses.

Biomarkers of insulin action during single soccer sessions before and after a 12-week training period in type 2 diabetes patients on a caloric-restricted diet

BackgroundWe investigated the biomarkers of insulin action as well as changes in free fatty acids and lactate concentration after an acute soccer session pre and post training with caloric-restricted diet versus diet alone in type 2 diabetes (T2D) patients. MethodsFifty-one middle-aged (61.1 ± 6.4 years) T2D patients were randomly allocated to the soccer+diet group (SDG) or the diet group (DG). The control group comprised T2D patients observing a caloric-restricted diet who did not receive soccer training. Over 12 weeks, SDG performed 3 × 40 min per week of soccer training. ResultsThe first soccer session for SDG induced acute increases in blood lactate (1.4 ± 0.1–6.0 ± 0.7 mmol/l, P < 0.05) and glucagon levels (112.1 ± 6.2–142.9 ± 8.0 pg/ml, P < 0.05), whereas glucose and insulin levels remained unchanged. Moreover, this session showed suppressed insulin levels as well as higher free fatty acids, lactate levels and glucagon/insulin ratio compared to DG (p < 0.05). After 12 weeks, a baseline decrease was observed in glucagon, leptin and lactate levels in SDG and DG (p < 0.05), whereas HOMA-IR, Adipo-IR and glucose levels were lower only in SDG (p < 0.05). At the last soccer training session, the blood lactate response was significantly lower than for the first session (4.0 ± 0.4 vs 6.0 ± 0.7 mmol/l). At 48 h pre intervention, a decrease was observed in leptin levels (p < 0.05), which remained lower post intervention. The positive correlation between leptin and insulin, and the lower levels after training, could be attributed to the improved insulin sensitivity along with the weight loss observed in both groups (~3.4 kg for DG and 3.7 kg for SDG). ConclusionAcute soccer sessions markedly improved insulin action markers in T2D patients, while the cumulative effects enhanced insulin sensitivity and decreased risk factors associated with cardiovascular disease after 12 weeks of intervention better than caloric-restricted diet.

Blood lactate responses to plyometric training in cricket players of different maturity level: a randomised controlled trial

Previous studies commonly examined the acute effect of plyometric exercise on blood lactate. To the best of our knowledge, no study has examined the effect of short-term plyometric training on blood lactate levels of cricket players. To investigate the effect of an 8 week plyometric training program on blood lactate concentration in cricket players of different maturity level. 55 healthy male cricket players (aged 14-35 years) were categorised into 14-17, 18-25 and 26-35 groups. Blood lactate concentration (BLAC) was assessed before and after 8 weeks of the intervention period. Regardless of the maturity level, a significant reduction in BLAC was observed in the experimental cricketers (P&lt;0.05) in response to 8 weeks of training. Blood lactate responses did not vary significantly in 14-17, 18-25 and 26-35 groups of cricket players following plyometric training. Plyometric training significantly reduced BLAC in cricket players despite non-significant differences amongst 14-17, 18-25 and 26-35 groups. Plyometric training could be recommended for adolescent (14-17) and adult cricketers (18-25 and 26-35) for improving their physiological capacities so as to develop optimal performance.

Multi-Stage Fitness Test Performance, V˙O2 Peak and Adiposity: Effect on Risk Factors for Cardio-Metabolic Disease in Adolescents

The role of physical activity in determining the metabolic health of adolescents is poorly understood, particularly concerning the effect on low-grade chronic inflammation (chronic elevation of pro-inflammatory cytokines IL-1β, IL-6, TNF-α and acute phase protein CRP, which is implicated in the etiology of atherosclerosis) and anti-inflammatory mediators such as IL-10. Furthermore, there is limited information on the mediating effects of performance on the multi-stage fitness test (MSFT), O2 peak and adiposity on risk factors for cardio-metabolic disease in adolescents.Purpose: To examine the effect of performance on the MSFT, O2 peak and adiposity on risk factors for cardio-metabolic diseases in adolescents.Methods: Following ethical approval, 121 adolescents (11.3 ± 0.8 year) completed the study. Risk factors for cardio-metabolic disease (circulating inflammatory cytokines, blood glucose and plasma insulin concentrations) was assessed using a fasted capillary blood sample. Participants were separated into quartiles based upon distance ran during the MSFT, the blood lactate response to submaximal exercise, O2 peak (determined during an uphill graded treadmill test), and adiposity (determined as the sum of four skinfolds). The blood lactate response to submaximal exercise and V02 peak were measured in a sub-group of participants. Data were analyzed using two-way between-subjects ANCOVA and multiple linear regression.Results: Participants with the lowest performance on the MSFT had higher blood concentrations of IL-6 (3.25 ± 0.25 pg mL-1) and IL-1β (4.78 ± 0.54 pg mL-1) and lower concentrations of IL-10 (1.80 ± 0.27 pg mL-1) when compared with all other quartiles (all p < 0.05). Yet, when categorized into O2 peak quartiles, no differences existed in any of the inflammatory mediators (all p > 0.05). Performance on the MSFT was the only predictor of IL-6 (β = -0.291, p = 0.031), IL-1β (β = -0.405, p = 0.005), IL-10 (β = 0.325, p = 0.021) and fasted blood glucose (β = -0.545, p < 0.001) concentrations. Adiposity was the only predictor of plasma insulin concentration (β = 0.515, p < 0.001) and blood pressure (diastolic: β = 0.259, p = 0.042; mean arterial pressure: β = 0.322, p = 0.011).Conclusion: Enhanced performance on the MSFT, but not O2 peak, was associated with a favorable inflammatory profile in adolescents; whilst adiposity adversely affected plasma insulin, diastolic and mean arterial blood pressure. These findings demonstrate that enhancing performance on the MSFT and maintaining a healthy body composition are a potential therapeutic intervention for the attenuation of risk factors for cardio-metabolic diseases in adolescents.