Lactate Minimum Speed Research Articles

Determination of speed and assessment of conditioning in horses submitted to a lactate minimum test-alternative approaches.

The maximal lactate steady state (MLSS) is a well-known gold standard method for determining the aerobic capacity of athletic horses. Owing to its high cost and complex execution, there is a search for standardized exercise tests that can predict this value in a single session. One of the methods described for this purpose is the lactate minimum test (LMT), which could be more accurate despite being adequate to predict MLSS. This study aimed to examine the impact of training on the speed corresponding to lactate minimum speed (LMS) and to apply new mathematical methods to evaluate the fitness level of horses based on the curve obtained by the LMT. Ten Arabian horses underwent a 6-week training program based on LMS calculated by second-degree polynomial regression (LMSP). In addition, the LMS was also determined by visual inspection (LMSV), bi-segmented linear regression (LMSBI) and spline regression (LMSS). From the curve obtained during the LMT, it was possible to calculate angles α, β and ω, as well as the total area under the curve (AUCTOTAL) before (AUCPRELMS) and after (AUCPOSLMS) the LMS. The methods for determining the LMS were evaluated by ANOVA, intraclass correlation coefficient (ICC) and effect size (ES) by Cohen's d test. The Pearson correlation coefficient (r) between the proposed LMS determination methods and other mathematical methods was also calculated. Despite showing a good correlation (ICC >0.7), the LMS determination methods differed from each other (p < 0.05), albeit without a significant difference resulting from conditioning. There were reductions in α:β ratio, angle α, and AUCPOSTLMS, with the latter indicating lower lactate accumulation in the incremental phase of LMT after conditioning, in addition to an improvement in the animals' aerobic capacity. Considering that the most common methods for determining the LMS are applicable yet with low sensitivity for conditioning assessment, the approaches proposed herein can aid in analyzing the aerobic capacity of horses subjected to LMT. The mathematical models presented in this paper have the potential to be applied in human lactate-guided training program trials with a comparable study basis.

Effect of Lactate Minimum Speed-Guided Training on the Fluid, Electrolyte and Acid-Base Status of Horses.

The effect of lactate minimum speed (LMS)-guided training on horses' homeostasis is still unknown. Thus, this study aimed to evaluate the effect of an LMS-guided training program on the fluid, electrolyte and acid-base status of horses. Ten untrained Arabian horses were submitted to an LMS test on a treadmill before and after six weeks of training. The training intensity was 80% of the LMS in the first three sessions and 100% of the LMS in the other sessions. The venous blood was collected before (T-1) and after (T-2) training at rest, during and after the LMS test for lactate, pH, pCO2, HCO3-, and electrolyte measurements. The LMS and strong ion difference (SID4) were calculated. A mild increase in the mean values (p > 0.05) was observed at rest in T-2 in comparison with T-1 in the following variables: pH (from 7.436 ± 0.013 to 7.460 ± 0.012), pCO2 (from 42.95 ± 1.58 to 45.06 ± 0.81 mmHg), HCO3- (from 27.01 ± 1.02 to 28.91 ± 0.86 mmol/L), and SID4 (from 33.42 ± 1.45 to 35.06 ± 2.94 mmol/L). During T-2, these variables were more stable than during T-1. Despite the improvement in fitness, the LMS did not indicate a significant difference (from 5.40 ± 0.55 to 5.52 ± 0.20 m/s). The results confirmed that the LMS-guided training program had a positive impact on the horses' acid-base status, although some adaptations are still required to improve their fitness.

The Effects of a Supramaximal Intermittent Training Program on Aerobic and Anaerobic Running Measures in Junior Male Soccer Players.

This study investigated the effectiveness of supplementing regular preseason soccer training with a supramaximal intermittent shuttle-run training (ISRT) model prescribed from Carminatti's Test peak speed (PST-CAR) in aerobic performance-related indices and sprinting speed in male junior soccer players. Twenty-three national-level soccer players (mean ± SD; age 18.07 ± 0.9 y, body height 1.76 ± 0.65 m, body mass 71.9 ± 8.7 kg) were assigned to either an experimental group (EG; n = 13) performing ISRT + soccer training or a control group (CG; n = 10) that followed regular preseason soccer training alone. The following tests were applied before and after the eight-week training intervention: (i) incremental treadmill tests (VO2max and lactate minimum speed - LMS); (ii) linear 30-m sprint test and Carminatti's Test (PST-CAR). Results indicated larger gains for the EG in LMS (Δ = 9.53% vs. 2.82%) and PST-CAR (Δ = 5.50% vs. 2.10%) than in the CG. Furthermore, changes in VO2max produced higher effect size (d) values for the EG (Δ = 6.67%; d = 0.59) than the CG (Δ = 1.88%; d = 0.18). Both groups improved (p = 0.002) their flying 20-m sprint speed (EG: Δ = 1.01%; CG: Δ = 1.56%). However, small decreases were observed for 10-m sprint speed in the CG (Δ = -2.19%; d = -0.44), while only trivial changes were noticed for the EG (Δ = -0.50%; d = -0.16). Our data support that additional supramaximal ISRT is an effective training stimulus to enhance aerobic performance-related indices and promote small improvements in maximal running speed without impairing the soccer players' acceleration capacity. This study also shows that PST-CAR can be useful for individualizing running intensity in supramaximal ISRT modes.

Effect of Lactate Minimum Speed-Guided Conditioning on Selected Blood Parameters of Horses

During exercise, equines can suffer severe water and electrolyte imbalances depending on the intensity and duration. In this sense, conditioning aims to promote adaptations to the organism in order to maintain cardiovascular and thermoregulatory stability during exertion. This study aimed to evaluate the effect of conditioning guided by lactate minimum speed (LMS) test on the blood osmolality of horses. We hypothesized that after conditioning the blood osmolality would vary less during exercise and that LMS could be used in equine conditioning program. Ten Arabian horses were evaluated before (ET 1) and after (ET 2) 6 weeks of conditioning. The conditioning intensity was established from the LMS during ET 1. The blood was obtained at rest and during the ETs. An increase in LMS and a decrease in lactate were seen in individual horses; however, these differences were not significant at a group level. No change in blood osmolality was observed when comparing the ETs. The plasma volume remained unchanged in ET 2. The conditioning guided by LMS improved the animals’ fitness, which was evidenced by the lower lactate production in ET 2. The fact that the osmolality kept unchanged proves the effectiveness of the osmotic blood balance during exercise, as its control involves the interaction of different systems. Body adaptations occurred with conditioning, providing greater homeostasis control since the plasma volume remained stable in ET 2. It was concluded that the LMS test can be used to define an effective equine conditioning program even though some adjustments are still necessary.

Monitoring Training Load, Immune-Endocrine, Autonomic Nervous System Responses, and Swimming Performance in Women’s Water Polo

ABSTRACT Purpose: The purposes of the study were to: i) verify the variations in training load and the subsequent effects on swimming performance parameters, biochemical parameters, and autonomic nervous activity during a water polo season; ii) investigate the sensitivity of physiological markers in tracking training load and performance variations, and iii) verify the overreaching prevalence. Method: The training load of 20 female water polo players was monitored (using the session rating of perceived exertion method [sRPE], training monotony, and strain), and the lactate minimum speed (LMS), repeated sprint ability (RSA), plasma hormone and glutamine concentration, salivary immunoglobulin A (SIgA), and heart rate variability (lnRMSSD) were evaluated during the season. Result: The training load parameters were higher in the competitive cycle (p ≤ 0.002). The LMS improved only in the general cycle from baseline (p = .015), while the RSA best time improved in the general (p = .002) and specific cycles (p = .012) from baseline and deteriorated in the competitive from general cycle (p = .008). The SIgA secretion rate presented a reduction only in the specific cycle from baseline (p = .032), while the lnRMSSD increased in the general (p = .038) and competitive (p < .001) cycles from baseline. Five athletes were diagnosed as overreaching state. Conclusion: Therefore, the physiological markers (i.e., plasma hormone and glutamine concentration, SIgA, and lnRMSSD) showed little sensitivity to detect changes in training load and swimming performance. The higher training loads applied in the competitive cycle seem to limit swimming performance gains.

Profiling the Aerobic Window of Horses in Response to Training by Means of a Modified Lactate Minimum Speed Test: Flatten the Curve.

There is a great need for objective external training load prescription and performance capacity evaluation in equestrian disciplines. Therefore, reliable standardised exercise tests (SETs) are needed. Classic SETs require maximum intensities with associated risks to deduce training loads from pre-described cut-off values. The lactate minimum speed (LMS) test could be a valuable alternative. Our aim was to compare new performance parameters of a modified LMS-test with those of an incremental SET, to assess the effect of training on LMS-test parameters and curve-shape, and to identify the optimal mathematical approach for LMS-curve parameters. Six untrained standardbred mares (3–4 years) performed a SET and LMS-test at the start and end of the 8-week harness training. The SET-protocol contains 5 increments (4 km/h; 3 min/step). The LMS-test started with a 3-min trot at 36–40 km/h [until blood lactate (BL) > 5 mmol/L] followed by 8 incremental steps (2 km/h; 3 min/step). The maximum lactate steady state estimation (MLSS) entailed >10 km run at the LMS and 110% LMS. The GPS, heartrate (Polar®), and blood lactate (BL) were monitored and plotted. Curve-parameters (R core team, 3.6.0) were (SET) VLa1.5/2/4 and (LMS-test) area under the curve (AUC>/<LMS), LMS and Aerobic Window (AW) via angular vs. threshold method. Statistics for comparison: a paired t-test was applied, except for LMS: paired Wilcoxon test; (p < 0.05). The Pearson correlation (r > 0.80), Bland-Altman method, and ordinary least products (OLP) regression analyses were determined for test-correlation and concordance. Training induced a significant increase in VLa1.5/2/4. The width of the AW increased significantly while the AUC</>LMS and LMS decreased post-training (flattening U-curve). The LMS BL steady-state is reached earlier and maintained longer after training. BLmax was significantly lower for LMS vs. SET. The 40° angular method is the optimal approach. The correlation between LMS and VMLSS was significantly better compared to the SET. The VLa4 is unreliable for equine aerobic capacity assessment. The LMS-test allows more reliable individual performance capacity assessment at lower speed and BL compared to SETs. The LMS-test protocol can be further adapted, especially post-training; however, inducing modest hyperlactatemia prior to the incremental LMS-stages and omitting inclusion of a per-test recovery contributes to its robustness. This LMS-test is a promising tool for the development of tailored training programmes based on the AW, respecting animal welfare.

Predicting the individual lactate minimum speed by T10 and T30 in swimming.

This study investigated the relationship between the lactate minimum (LAC<inf>min</inf>) and the 10- (T10) and 30-min (T30) continuous tests in swimmers. Twelve swimmers (78.1±3.1% of the world record) performed the LAC<inf>min</inf> (hyperlactatemia: 2×50 m all-out 8-min apart, incremental part: N.×300 m 30-s apart), T30 and T10 using the front-crawl stroke. Blood samples were collected after each stage of LAC<inf>min</inf> for lactate analysis. Swimmers were oriented to swim as fast and as constant as possible in T10 and T30. Speeds in T10 (1.28±0.10 m/s) and T30 (1.21±0.09 m/s) were different from LAC<inf>min</inf> (1.24±0.09 m/s). T10 and T30 speeds presented a nearly perfect relationship with LAC<inf>min</inf> and acceptable prediction errors (T10: r=0.938, P<0.001, 0.033 m/s; T30: r=0.927, P<0.001, 0.036 m/s, respectively). T10 and T30 can be used as indirect tests for evaluating LAC<inf>min</inf> in swimming.

Effects of Seasonal Training Load on Performance and Illness Symptoms in Water Polo.

Brisola, GMP, Claus, GM, Dutra, YM, Malta, ES, de Poli, RAB, Esco, MR, and Zagatto, AM. Effects of seasonal training load on performance and illness symptoms in water polo. J Strength Cond Res 34(2): 406-413, 2020-The purpose of the study was to describe the training load distribution of a young female water polo team in different cycles of the season and verify its subsequent effects on specific fitness measured by the repeated sprints ability (RSA) test, aerobic endurance measured by the lactate minimum test, incidence and severity of upper respiratory tract infection (URTI) symptoms, and muscle damage markers. The training load (i.e., rating of perceived exertion × session duration) of 20 young female water polo players (mean ± SD: age = 15.65 ± 1.3 years; body mass = 60.93 ± 11.0 kg; height = 1.62 ± 0.1 m) was monitored, and the incidence and severity of URTI was assessed during part of the season. In addition, we assessed the lactate minimum speed (LMS), RSA, creatine kinase (CK), and lactate dehydrogenase (LDH) blood concentration during the season. The level of significance set was p < 0.05. The training loads were higher in the specific period (p < 0.01), whereas a high incidence of URTI was observed in the general cycle. The LMS was greater in the general cycle (p < 0.05), whereas total time and best time in the RSA test were greater in the competitive cycle (p < 0.05). The CK and LDH concentrations were significantly lower during the competitive cycle (p < 0.01). The general cycle of a female water polo team is critical regarding URTI and muscle damage, even with smaller training loads than the specific period.

Characteristics and effect of 8-week soccer training on lactate minimum speed

Purpose This study aimed to (1) characterize 8 weeks of specific soccer training according to heart rate (HR) zones and speed zones, and (2) verify the effects of 8 weeks of specific soccer training on lactate minimum speed (LMS), and the respective HR (HRLMS) of professional soccer players.

Relationship of aerobic and anaerobic parameters with 400 m front crawl swimming performance.

The aims of the present study were to investigate the relationship of aerobic and anaerobic parameters with 400 m performance, and establish which variable better explains long distance performance in swimming. Twenty-two swimmers (19.1±1.5 years, height 173.9±10.0 cm, body mass 71.2±10.2 kg; 76.6±5.3% of 400 m world record) underwent a lactate minimum test to determine lactate minimum speed (LMS) (i.e., aerobic capacity index). Moreover, the swimmers performed a 400 m maximal effort to determine mean speed (S400m), peak oxygen uptake () and total anaerobic contribution (CANA). The CANA was assumed as the sum of alactic and lactic contributions. Physiological parameters of 400 m were determined using the backward extrapolation technique ( and alactic contributions of CANA) and blood lactate concentration analysis (lactic anaerobic contributions of CANA). The Pearson correlation test and backward multiple regression analysis were used to verify the possible correlations between the physiological indices (predictor factors) and S400m (independent variable) (p < 0.05). Values are presented as mean ± standard deviation. Significant correlations were observed between S400m (1.4±0.1 m·s-1) and LMS (1.3±0.1 m·s-1; r = 0.80), (4.5±3.9 L·min-1; r = 0.72) and CANA (4.7±1.5 L·O2; r= 0.44). The best model constructed using multiple regression analysis demonstrated that LMS and explained 85% of the 400 m performance variance. When backward multiple regression analysis was performed, CANA lost significance. Thus, the results demonstrated that both aerobic parameters (capacity and power) can be used to predict 400 m swimming performance.

Running Anaerobic Sprint Test, Lactate Minimum and Critical Velocity Protocol in Shuttle Futsal Testing

The aims of this study were to investigate whether the running anaerobic sprint test, lactate minimum and critical velocity protocol can be applied in shuttle futsal testing, and to investigate if these protocols provide related variables. Seven male welltrained futsal players were evaluated. The lactate minimum test (LacMin) consisted of three phases: a) a hyperlactatemia phase using the running anaerobic sprint test (RAST); b) recovery phase; c) an incremental shuttle test for the lactate minimum speed (LMS) determination. Successful rate (SR) was calculated for feasibility analysis. Peak, mean and minimum power and fatigue index were obtained by the RAST application (six bouts – 35 meters). The critical velocity protocol (CV) was applied through three exhaustive shuttle tests (12, 13 and 14 km/h) with distances of 20 meters. Critical velocity (Cv) and anaerobic running capacity (ARC) were analysed by the linear (velocity vs.1/tlim) and hyperbolic (time vs.velocity) models. Fits of regression (R²) were considered as the main result for feasibility analysis of CV. ANOVA showed a difference between linear (11.04 ±0.55 km/h) and LMS (9.67 ±0.50 km/h), and no significant correlation was observed between them. High SR (85.71%) was observed for LacMin, and high R² for CV (linear-R² = 0.99 ±0.04; hyperbolic-R² = 0.98 ±0.02).Overall, the RAST, LacMin and CV can be successfully applied in shuttle futsal testing, nonetheless, precaution is necessary since the test results were not related.

Comparison Between Lactate Minimum and Critical Speed Throughout Childhood and Adolescence in Swimmers

This study aimed to examine the influence of age and degree of maturity on the comparison and relationship between lactate minimum intensity (LM) and critical speed (CS) throughout childhood and adolescence in swimmers. Forty-six male swimmers aged between 10 and 18 years were divided into three age groups according to pubertal stages and training status. Maximal efforts of 100 and 400 m and the LM protocol with 200 m performances were executed. CS was determined with a 3-distances combination (100, 200, and 400 m). One-way and mixed analysis of variance for repeated measures, Bland-Altman, Pearson correlation, percentage difference, and effect size were used to compare and examine the relationship between variables in each age group. The results revealed that LM and CS had differences in comparison with one another throughout childhood and adolescence in swimmers, because CS clearly underestimated LM in the 10 to 12.6-year age group, while overestimating it in the 15.4 to 18-year age group of swimmers. Thus, coaches and swimmers must be aware of the age-dependency of CS for indices of aerobic endurance measurements in the initial ages of systematized swimming training.

Comparison of maximal lactate steady state with V2, V4, individual anaerobic threshold and lactate minimum speed in horses

The anaerobic threshold is a physiologic event studied in various species. There are various methods for its assessment, recognized in the human and equine exercise physiology literature, several of these involving the relationship between blood lactate concentration (LAC) and exercise load, measured in a standardized exercise test. The aim of this study was to compare four of these methods: V2, V4, individual anaerobic threshold (IAT) and lactate minimum speed (LMS) with the method recognized as the gold standard for the assessment of anaerobic threshold, maximal lactate steady-state (MLSS). The five tests were carried out in thirteen trained Arabian horses, in which velocities and associated LAC could be measured. The mean velocities and the LAC associated with the anaerobic threshold for the five methods were respectively: V2 = 9.67±0.54; V4 = 10.98±0.47; V IAT = 9.81±0.72; V LMS = 7.50±0.57 and V MLSS = 6.14±0.45m.s-1 and LAC IAT = 2.17±0.93; LAC LMS = 1.17±0.62 and LAC MLSS = 0.84±0.21mmol.L-1. None of the velocities were statistically equivalent to V MLSS (P&lt;0.05). V2, V4 and V LMS showed a good correlation with V MLSS , respectively: r = 0.74; r = 0.78 and r = 0.83, and V IAT did not significantly correlate with V MLSS. Concordance between the protocols was relatively poor, i.e., 3.28±1.00, 4.84±0.30 and 1.43±0.32m.s-1 in terms of bias and 95% agreement limits for V2, V4 and LMS methods when compared to MLSS. Only LAC LMS did not differ statistically from LAC MLSS. Various authors have reported the possibility of the assessment of anaerobic threshold using rapid protocols such as V4 and LMS for humans and horses. This study corroborates the use of these tests, but reveals that adjustments in the protocols are necessary to obtain a better concordance between the tests and the MLSS.

Comparison of the lactate minimum speed and the maximal lactate steady state to determine aerobic capacity in purebred Arabian horses

AIM: To compare five different protocols for estimating the lactate minimum speed (LMS) with that for estimating the maximal lactate steady state (MLSS) in Arabian horses, in order to obtain a more rapid method for monitoring aerobic capacity and prescribing training schedules.METHODS: Eight purebred Arabian horses were conditioned to exercise on a treadmill for 12 days then submitted to three to five exercise sessions to determine the MLSS. Blood samples were collected from a jugular catheter at specific intervals for measurement of lactate concentrations. The MLSS was the velocity maintained during the last 20 minutes of constant submaximal exercise, at which the concentration of lactate increased by no more than 1.0 mmol/L. The LMS test protocols (P1 − P5) included a warm-up period followed by a high-intensity gallop. The speed was then reduced to 4 m/s, and the incremental portion of the test was initiated. In P1, P2, and P3, the velocity increment was 0.5 m/s, and the duration of each incremental stage was three, five and seven minutes, respectively. In P4 and P5, the velocity increments were 1.0 and 1.5 m/s, respectively, and the duration of the stages was fixed at five minutes each. A second-degree polynomial function was fitted to the lactate-velocity curve, and the velocity corresponding to the lowest concentration of lactate was the LMS.RESULTS: Only the mean LMS determined by P1 and P2 did not differ from the velocity determined by the MLSS test (p > 0.1). There was a strong correlation (r >0.6) between P1 and the MLSS velocity. A limits of agreement plot revealed that the best agreement occurred between the MLSS test and P1 (mean bias = 0.14 m/s), followed by P2 (bias = −0.22 m/s). The lactate concentrations associated with the various LMS protocols did not differ.CONCLUSIONS: This study shows the variation between protocols of the LMS test for determining the onset of blood lactate accumulation but also reveals that, at least for Arabian horses, the P1 protocol of the LMS has good agreement with the MLSS.

Uzun Süreli Aerobik ve Anaerobik Egzersizlerin Kan Nitrik Oksit Seviyeleri Üzerine Etkisi

Objective: Nitric oxide (NO) is a gas which has vasodilator, antioxidant and metabolic regulator features. The positive effect of aerobic exercise is well known on the production of NO in healthy men. However, the effects of chronic anaerobic exercise on blood NO levels remain unclear. The aim of the present study was to investigate the effects of both chronic aerobic and anaerobic exercise on basal serum nitric oxide (BSNO) levels, and the relationships between BSNO and some aerobic and anaerobic performance parameters. Material and Methods: Three groups participated in the present study, each of them was composed of 11 healthy men with similar physical characteristics. The groups consisted of volleyball players as the anaerobic group (AnG), swimmers as the aerobic group (AeG) with long-term exercise background and volunteers who did not exercise regularly as the control group (CG). BSNO (as total nitrite) analysis was determined in fasting venous blood by using Griess method. Mean power and peak power as the criteria of anaerobic performance were determined by using Wingate test, and lactate minimum speed (LMS) was determined as the criterion of aerobic endurance with the LMS test based on lactate elimination. Finger tip lactate measurements were taken during certain segments of LMS test. Results: The BSNO value of the AeG was significantly higher compared to the CG (90.34 vs. 74.39 µM), but it was not different from that of the AnG (80.02 µM). No significant relationships were observed between the BSNO and LMS values in any group. The LMS value of the AeG was significantly greater than that in the CG (11.59 vs. 10.27 km/h). Peak power (13.11 vs. 9.84 w/kg) and mean power (8.55 vs. 7.36 w/kg) were significantly greater in the AnG compared to the AeG. A positive correlation was found between BSNO in the AeG and peak power (r=0.648, p=0.031) in the AeG. Conclusion: Based on the results of the present study, it is suggested that regular aerobic exercise may improve blood NO levels while anaerobic exercise does not; nevertheless, NO may play a role in both aerobic and anaerobic adaptations to exercise.

Influence of recovery manipulation after hyperlactemia induction on the lactate minimum intensity

This study analyzed the influence of recovery phase manipulation after hyperlactemia induction on the lactate minimum intensity during treadmill running. Twelve male runners (24.6 +/- 6.3 years; 172 +/- 8.0 cm and 62.6 +/- 6.1 kg) performed three lactate minimum tests involving passive (LMT(P)) and active recoveries at 30%vVO(2max) (LMT(A30)) and 50%vVO(2max) (LMT(A50)) in the 8-min period following initial sprints. During subsequent graded exercise, lactate minimum speed and VO(2) in LMT(A50) (12.8 +/- 1.5 km h(-1) and 40.3 +/- 5.1 ml kg(-1) min(-1)) were significantly lower (P < 0.05) than those in LMT(A30) (13.3 +/- 1.6 km h(-1) and 42.9 +/- 5.3 ml kg(-1) min(-1)) and LMT(P) (13.8 +/- 1.6 km h(-1) and 43.6 +/- 6.1 ml kg(-1) min(-1)). In addition, lactate minimum speed in LMT(A30) was significantly lower (P < 0.05) than that in LMT(P). These results suggest that lactate minimum intensity is lowered by active recovery after hyperlactemia induction in an intensity-dependent manner compared to passive recovery.

The effect of pre-test carbohydrate ingestion on the anaerobic threshold, as determined by the lactate-minimum test

The purpose of this study was to investigate the effect of pre-test carbohydrate (CHO) ingestion on anaerobic-threshold assessment using the lactate-minimum test (LMT). Fifteen competitive male distance runners capable of running 10 km in 33.5-43 min were used as subjects. LMT was performed following CHO (2x300 mL, 7% solution) or comparable placebo (Pl) ingestion, in a double-blind, randomized order. The LMT consisted of two high-intensity 1 min treadmill runs (17-21 km.h(-1)), followed by an 8 min recovery period. Subsequently, subjects performed 5 min running stages, incremented by 0.6 km.h(-1) and separated by 1 min blood-sampling intervals. Tests were terminated after 3 consecutive increases in blood-lactate concentration ([La]) had been observed. Finger-tip capillary blood was sampled for [La] and blood-glucose determination 30 min before the test's onset, during the recovery phase following the 2 high-intensity runs, and following each of the subsequent 5 min stages. Heart rate (HR) and rating of perceived exertion (RPE) were recorded after each stage. The lactate-minimum speed (LMS) was determined from the individual [La]-velocity plots and was considered reflective of the anaerobic threshold. Pre-test CHO ingestion had no effect on LMS (13.19+/-1.12 km.h(-1) vs. 13.17+/-1.08 km.h(-1) in CHO and Pl, respectively), nor on [La] and glucose concentration at that speed, or on HR and RPE responses. Pre-test CHO ingestion therefore does not affect LMS or the LMT-estimated anaerobic threshold.

Correlações entre protocolos de determinação do limiar anaeróbio e o desempenho aeróbio em nadadores adolescentes

O objetivo do presente estudo foi correlacionar as velocidades de limiar anaeróbio (LAn) obtidas a partir de concentrações fixas de lactato (VLAn 4 e VLAn 3,5mM), velocidade de lactato mínimo (VLac min) e velocidade crítica (VC) determinada a partir de diferentes distâncias e número de coordenadas: VC1 (50/100/200m), VC2 (100/200/400m), VC3 (50/100/200/400m) e VC4 (200/400m) com o desempenho nos 400m(s) em nadadores adolescentes. Fizeram parte da amostra 15 nadadores (10 meninos e cinco meninas = 14,7 ± 0,7 anos; 61,9 ± 8,5kg; 171,1 ± 8,8cm) de nível nacional, com experiência entre cinco e sete anos na natação competitiva. Para análise das correlações entre os índices e o desempenho nos 400m(s) foi utilizado o coeficiente de correlação de Pearson. O nível de significância adotado foi de p &lt; 0,01. As correlações entre a VLAn 4mM, VLAn 3,5mM, VLac min e o desempenho nos 400m(s) foram de r = -0,63, r = -0,90 e r = -0,91, respectivamente (p &lt; 0,01). As correlações entre a VC1 (50/100/200m), VC2 (100/200/400m), VC3 (50/100/200/400m), VC4 (200/400m) e o desempenho nos 400m(s) foram: r = -0,62, r = -0,97, r = -0,98 e r = -0,94, respectivamente (p &lt; 0,01). Sugere-se que o LAn determinado a partir da concentração fixa de lactato de 3,5mM, bem como a VLac min e a VC obtidas por meio de distâncias maiores parecem ser os mais adequados índices preditores do desempenho aeróbio nos nadadores adolescentes estudados. Além disso, o número de coordenadas parece não influenciar a relação entre a VC e desempenho aeróbio.

Determination of the anaerobic threshold and maximal lactate steady state speed in equines using the lactate minimum speed protocol

Maximal blood lactate steady state concentration (MLSS) and anaerobic threshold (AT) have been shown to accurately predict long distance events performance and training loads, as well, in human athletes. Horse endurance races can take up to 160 km and, in practice, coaches use the 4 mM blood lactate concentration, a human based fixed concentration to establish AT, to predict training loads to horse athletes, what can lead to misleading training loads. The lactate minimum speed (LMS) protocol that consists in an initial elevation in blood lactate level by a high intensity bout of exercise and then establishes an individual equilibrium between lactate production and catabolism during progressive submaximal efforts, has been proposed as a nonfixed lactate concentration, to measure individual AT and at the same time predicts MLSS for human long distance runners and basketball players as well. The purpose of this study was to determine the reliability of the LMS protocol in endurance horse athletes. Five male horses that were engaged on endurance training, for at least 1 year of regular training and competition, were used in this study. Animals were submitted to a 500 m full gallop to determine each blood lactate time to peak (LP) after these determinations, animals were submitted to a progressive 1000 m exercise, starting at 15 km h(-1) to determine LMS, and after LMS determination animals were also submitted to two 10,000 m running, first at LMS and then 10% above LMS to test MLSS accuracy. Mean LP was 8.2+/-0.7 mM at approximately 5.8+/-6.09 min, mean LMS was 20.75+/-2.06 km h(-1) and mean heart rate at LMS was 124.8+/-4.7 BPM. Blood lactate remained at rest baseline levels during 10,000 m trial at LMS, but reached a six fold significantly raise during 10% above LMS trial after 4000 and 6000 m (p<0.05) and (p<0.01) after 8000 and 10,000 m. In conclusion, our adapted LMS protocol for horse athletes proposed here seems to be a reliable method to state endurance horse athletes LT and MLSS.

Effect of the passive recovery period on the lactate minimum speed in sprinters and endurance runners

The objective of this study was to verify the effect of the passive recovery time following a supramaximal sprint exercise and the incremental exercise test on the lactate minimum speed (LMS). Thirteen sprinters and 12 endurance runners performed the following tests: (1) a maximal 500 m sprint followed by a passive recovery to determine the time to reach the peak blood lactate concentration; (2) after the maximal 500 m sprint, the athletes rested eight mins, and then performed 6 x 800 m incremental test, in order to determine the speed corresponding to the lower blood lactate concentration (LMS1) and; (3) identical procedures of the LMS1, differing only in the passive rest time, that was performed in accordance with the time to peak lactate (LMS2). The time (min) to reach the peak blood lactate concentration was significantly higher in the sprinters (12.76 +/- 2.83) than in the endurance runners (10.25 +/- 3.01). There was no significant difference between LMS 1 and LMS2, for both endurance (285.7 +/- 19.9; 283.9 +/- 17.8 m/min; r = 0.96) and sprint runners (238.0 +/- 14.1; 239.4 +/- 13.9 m/min; r = 0.93), respectively. We can conclude that the LMS is not influenced by a passive recovery period longer than eight mins (adjusted according with the time to peak blood lactate), although blood lactate concentration may differ at this speed. The predominant type of training (aerobic or anaerobic) of the athletes does not seem to influence the phenomenon previously described.