Onset Of Blood Lactate Accumulation Research Articles

Anaerobic Threshold in Stand-up Paddle: Comparison Between Direct and Alternative Methods.

Balikian, P, Gomes de Araujo, G, Prado, ES, Ryan Geraldes, AA, Marinho de Lima, AH, and Mendes, EV. Anaerobic threshold in stand-up paddle: comparison between direct and alternative methods. J Strength Cond Res 36(7): 1896-1900, 2022-The purpose of this study was to test the validity of alternative protocols, mean velocity during 30 minutes of continuous effort (V30min) and critical velocity (CV), to estimate the anaerobic threshold in stand-up paddle (SUP). Eight athletes performed: 3 maximal efforts at 400-, 500-, and 800-m distances to determine CV values, using the distance-time relationship; 3 efforts at 85, 90, and 100% of maximal 500-m effort to determine the velocity related to 3.5 mmol·L-1 of lactate, assumed as the onset of blood lactate accumulation (OBLA) and; a 30-minute continuous effort to determine the V30min. All evaluations were separated by 48 hours, with the athletes using their own boards and paddles in the water. No differences were observed between the OBLA (2.35 ± 0.13 m·s-1) and alternative methods (CV: 2.42 ± 0.20 m·s-1; p = 0.10 and V30min: 2.32 ± 0.13 m·s-1; p = 0.63). Although strong correlations were observed between the OBLA and alternative methods (CV: r = 0.84 and V30min: r = 0.94), the limits of agreement were higher in CV (±0.23 m·s-1) than V30min (±0.08 m·s-1). These results demonstrate that both the CV and V30min are valid to estimate the OBLA. In view of the specificity of SUP and the high levels of agreement, the use of the V30min is recommended to prescribe training intensities.

Work-matched High-intensity Interval And Moderate-intensity Continuous Training Adaptations On 17 Lactate Threshold Methods In Females

PURPOSE: to compare exercise training effects on 17 lactate threshold methods to 6 weeks (3x/week) of high-intensity interval training (HIIT) or moderate-intensity continuous training (MICT) in females. METHODS: 24 healthy sedentary females (mean ± SD: peak oxygen uptake 30.0 ± 3.2 mLᐧkg-1ᐧmin-1, peak power output 151 ± 21 W, body mass index 23.4 ± 2.6 kgᐧm-2) were randomly assigned to either HIIT or MICT. Participants performed a step-incremental test on a cycle ergometer (3-min stages of 25-W increments, starting at 25 W) pre- and post-training. The HIIT group (N = 12) performed a 10-min warm-up (power output (PO) at 70% of the maximal heart rate (HRmax)), and four 4-min intervals (PO at 90% HRmax) interspersed with 4-min recovery at 30 W. The MICT group (N = 12) performed 60-min continuous cycling (PO at 90% of the first lactate turning-point (LT1)). Lactate thresholds were analyzed as: Log-log, onset of blood lactate accumulation (OBLA, N = 5), fixed value above baseline (Bsln+, N = 3), Dmax and its modified versions (N = 5), lactate turning-points (LT1 and LT2), and the minimal lactate-intensity ratio (LTratio). A two-way analysis of variance was used to test differences within (post versus pre) and between groups. Additionally, the width of confidence intervals (CIwidth) from the delta change was calculated for each method and group. RESULTS: In the HIIT group, the intensity derived from all the methods significantly increased after training (p < 0.01), except for LTratio (p = 0.6). In the MICT group, the intensity from OBLA, Bsln+, and the modified Dmax methods significantly increased after training (p < 0.05), whereas Log-log, Dmax, LT1, LT2, and LTratio did not improve significantly (p > 0.05). The HIIT group showed a higher increase in intensity from the Dmax methods, and in LT1 and LT2 compared with the MICT group (p < 0.05). No differences were observed between the groups in the improvements of Log-log, OBLA, Bsln+, and LTratio. OBLA at 3.5 and 4.0 mM, and Dmax presented the narrowest CIwidth (range 7 - 12 W), while Bsln+ 0.5 mM, Bsln+ 1.0 mM, and Log-log had the widest CIwidth (range 24 - 32 W). CONCLUSIONS: In healthy sedentary females, improvements of the Dmax methods, LT1, and LT2 were superior in the HIIT group. The lowest intra-individual variability in response to training was observed in the Dmax and OBLA at 3.5 and 4.0 mM methods.

Reliability and Validity of Integrated External and Internal Load Ratios as Measures of Fitness in Academy Rugby Union Players.

Taylor, RJ, Sanders, D, Myers, T, and Akubat, I. Reliability and validity of integrated external and internal load ratios as measures of fitness in academy rugby union players. J Strength Cond Res 34(6): 1723-1730, 2020-This study aimed to assess the relationships between integrated ratios of external and internal load measures and aerobic fitness in 3 different training exercise protocols. Twelve academy rugby union players (aged; 17.6 ± 0.44 years, height; 179.4 ± 6.3 cm, body mass 83.3 ± 9.7 kg) performed a lactate threshold/V[Combining Dot Above]O2max test (LT/V[Combining Dot Above]O2max) followed by 3 exercise protocols; 760 m continuous shuttle running (20 m shuttle run at 9 km·h), sprint interval training (SIT: 6 × 6 seconds sprint with 54 seconds recovery), and a small-sided game (SSG: 6 vs. 6, 10 minutes on a 39 × 51 m pitch) on 2 occasions. A LT/V[Combining Dot Above]O2max test was used to determine velocity at lactate threshold (vLT) and at the onset of blood lactate accumulation (vOBLA), maximal oxygen uptake (V[Combining Dot Above]O2max) and the heart rate-blood lactate profile for the calculation of internal load (individualized training impulse or iTRIMP). The total distance (TD), PlayerLoad, metabolic power (MP), high-speed distance >15 km·h (HSD), very high-speed distance >18 km·h (VHSD) and individualized high-speed distance based on each player's vOBLA (iHSD) for the 3 exercise protocols were measured using Micro Electro Mechanical Systems/Global Positioning System technology. Bayesian analysis was used to assess the ratios validity and reliability. Ratios demonstrated large-to-very large associations with vOBLA (Rho = 0.64-0.76), vLT (Rho = 0.63-0.71). Reliability of the ratios ranged from 7.06 to 36.28% (coefficient of variation [CV]%). The results suggest that integrated load ratios from the SIT and SSG protocols provide a measure which is reliable with large-to-very large associations to submaximal aerobic fitness in rugby union.

The physiological correlates of variable gradient cycling performance

This study investigates the physiological correlates of computer simulated rolling terrain time-trial performance in a group of competitive cyclists. Twenty eight trained cyclists (age 33 ± 10 years, body mass 74.4 ± 7.3 kg, and peak oxygen uptake 64 ± 7 mL . kg -1. min -1 ) participated in this study. Cyclists initially completed a graded exercise test (GXT) to establish measures of peak power output (PPO), peak oxygen uptake ( O2peak), onset blood lactate accumulation (OBLA), ventilatory threshold (VT) and gross efficiency (GE). On a further occasion cyclists then completed a 20-km time-trial over a computer simulated rolling terrain course from which performance time and mean power output were determined. Pearson’s correlation (r) was used to examine the magnitude of the relationship between measures in the GXT and time-trial. There were large to very large (r = 0.51-0.9) correlations between performance time and mean power output in the time-trial and measures of absolute O2peak and PPO from the GXT. Correlations between time-trial performance time and physiological measures were further increased when physiological measures were expressed relative to body mass. The smallest correlations (r < 0.3) were reported between time-trial performance time and mean power output when anaerobic threshold parameters were reported as fractional utilisations of peak power. These findings support the use of body mass corrected variables for predicting performance in rolling terrain time-trials. Cyclists preparing for rolling terrain races are recommended to optimise their power to weight ratio to gain a performance advantage.

Changes in lactate kinetics underpin soccer performance adaptations to cycling-based sprint interval training

In adolescent soccer, 23% of the distance covers happens at speeds above onset of blood lactate accumulation which suggests that lactate kinetics may be important for soccer performance. We sought to determine the effectiveness of sprint interval training (SIT) on changing performance and lactate kinetics in adolescent soccer players. Thirteen elite soccer academy players (age 15 ± 0.5y) underwent baseline testing (0–10 m and 10–20 m sprint performance, Wingate anaerobic Test (WaNT) with blood lactate measurements and incremental VO2 peak test) before being allocated to control or SIT group. The control group maintained training whilst the HIT group carried out twice-weekly all-out effort cycle sprints consisting of 6 × 10 s sprint with 80 s recovery. There were significant time x group interactions for 10–20 m sprint time (Control pre: 1.32 ± 0.07 s post: 1.35 ± 0.08 s; SIT pre: 1.29 ± 0.04 s post: 1.25 ± 0.04 s; p = 0.01), Peak Power (Control pre: 13.1 ± 1.3 W.kg−1 post: 13.2 ± 1.47 W.kg−1; SIT pre: 12.4 ± 1.3 W.kg−1 post: 15.3 ± 0.7 W.kg−1; p = 0.01) and time to exhaustion (Control pre: 596 ± 62 s post: 562 ± 85 s; SIT pre: 655 ± 54 s post: 688 ± 55 s; p = 0.001). The changes in performance were significantly correlated to changes in lactate kinetics (power: r = 0.55; 10–20 m speed: r = −0.54; time to exhaustion: r = 0.55). Therefore, cycle based SIT is an effective training paradigm for elite adolescent soccer players and the improvements in performance are associated with changes in lactate kinetics.

Effect of lactate supplementation on V̇O&lt;sub&gt;2peak&lt;/sub&gt; and onset of blood lactate accumulation: A double-blind, placebo-controlled trial

Background: Professional and recreational athletes use ergogenic aids to enhance aerobic performance, facilitate training adaptations, and reduce recovery time. While the ergogenic effect of commonly marketed and commercially available ergogenic aids (i.e., sodium bicarbonate and &#946;-alanine) have been investigated extensively, the effectiveness of lactate supplementation on aerobic capacity markers (i.e., V&#775;O2peak and the onset blood lactate accumulation) has not been thoroughly investigated. Objective: The purpose of this study was to examine the effect of lactate supplementation on V&#775;O2peak and the onset blood lactate accumulation (OBLA). Methods: Eighteen healthy individuals (14 men and 4 women, age: 24 &#177; 5 years, height: 171 &#177; 7 cm, body mass: 76 &#177; 17 kg) participated in a double-blind-placebo-controlled study and were randomly assigned to one of 2 groups: placebo (PLA, n = 8), or supplement (SUP, n = 10) consisting of a combination of magnesium lactate dihydrate and calcium lactate monohydrate. Prior to and following supplementation, participants performed a cycling graded exercise test to determine V&#775;O2peak, time to exhaustion, power output, V&#775;O2 and % V&#775;O2peak associated with OBLA. Results: There were no statistically significant differences between PLA and SUP in direct markers of aerobic capacity (all p &gt; .05). Heart rate at OBLA was reduced by 6 &#177; 6% in the PLA group post-supplementation compared to pre-supplementation (p = .03).Conclusions: Lactate supplementation did not present an advantage over a placebo in improving aerobic capacity. The results from this study support those by previous investigators suggesting that there is no physiological rationale for using lactate supplementation to improve aerobic capacity and/or performance.

Mobilization and Fcγ-Receptor Expression of Six NK Cell Subsets During and After Acute Exercise

Natural killer (NK) cells are the most responsive lymphocytes during acute exercise, with increased concentrations. After exercise, NK cell levels drop below their resting level if the exercise intensity was high, but values usually recover within 1-3 hours. NK cells may be divided into CD56dim and CD56bright subsets. The CD56dim subset is the major population, representing about 80% of NK cells. Smaller subpopulations were recently studied for cell developments and diseases. We previously reported that exercise decreased the expression of Fcγ-receptor III (CD16); however, it is not yet understood how exercise affects these small subsets. PURPOSE: To clarify the effect of acute exercise on the mobilization and expression of CD16 on the six different NK cell subsets. METHODS: Healthy male students (n=6, 22.8±0.8 years old) exercised on a cycle ergometer for 30 min at intensities corresponding to the individual’s onset of blood lactate accumulation (70-85% maximum oxygen consumption). Venous blood samples were collected at rest (PRE), just before the end of exercise (END), 30 (POST 30), 60 (POST 60), 120 (POST 120), and 180 (POST 180) min after exercise. Cell counts and proportions of total lymphocytes expressing CD16-CD56bright (R1), CD16+CD56bright (R2), CD16-CD56dim (R3), CD16dimCD56dim (R4), CD16brightCD56dim (R5) and CD16brightCD56- (R6) subsets were determined. CD16 expressions of these subsets were also examined by flow cytometry. ANOVA was used for statistical analyses. RESULTS: Exercise induced changes in NK cell concentration in CD56dim (R3, p=0.04; R4, p<0.01; R5, p<0.01) and CD56- (R6, p<0.01) subsets. However significant changes between time points were only found in R5. In this subset, NK cell counts increased from PRE (356±151 cells/μL) to END (1182±159 cells/μL, p<0.01) and decreased under the PRE-level at POST 30 (108±27 cells/μL, p<0.01) and POST 60 (106±70 cells/μL, p<0.01). There were no changes in CD56bright (R1, R2) subsets. These cell mobilizations were reflected in proportions to the total lymphocyte count. Expressions of CD16 were down-regulated at END in R5 (-502±135, p<0.01) and R6 (-416±99, p<0.01) then recovered at POST 30. CONCLUSIONS: These results suggest that the influence of acute exercise on NK cell mobilization and CD16 expression are clear in subset R5, but not in R1 and R2.

Spring-mass characteristics during human locomotion: Running experience and physiological considerations of blood lactate accumulation

The aim of this study was to examine how running experience affects leg stiffness (Kleg) and spring-mass characteristics during running stages associated with the onset of blood lactate accumulation (OBLA). Seven trained (66.9 ± 4.8 kg; 182 ± 4.0 cm; 23.1 ± 3.1 years) and 13 untrained (78.5 ± 7.6 kg; 182 ± 3.0 cm; 20.3 ± 1.5 years) runners completed an incremental treadmill run. Running velocity was increased by 1 km.h−1 every four minutes and blood lactate samples were taken at every stage, in addition to a 10 s video recording using ‘Runmatic’. Once 4 mmol L−1 (OBLA; the second lactate turn point) had been reached one more stage was completed. Spring-mass characteristics across groups and at pre-OBLA, OBLA and post-OBLA were compared. The velocity at OBLA was higher for the trained runners compared to the untrained runners (18 ± 0.7 vs 11 ± 1.3 km.h−1, p < 0.001). Kleg was similar between untrained and trained runners across each stage (15.8 ± 0.3 vs 14.3 ± 0.3 kN.m) and did not change between stages, yet spring-mass characteristics differed between groups. Vertical stiffness increased in the trained runners from pre-OBLA to post-OBLA (45.5 ± 3.35–51.9 ± 3.61 kN−1), but not in untrained runners (35.0 ± 5.2–39.6 ± 5.7 kN−1). Kleg was strongly related to Fpeak for trained runners only (r = 0.79; untrained runners, r = 0.34). Kleg was unaffected by physiological training status and was maintained across all OBLA stages. Trained runners appear to have optimised their spring-mass system in a homogenous manner, whilst less consistent spring-mass characteristics were observed in untrained runners.

Borg’s category ratio-scale (CR-10) is useful to predict the onset of blood lactate accumulation (OBLA) in young Mexicans adults, regardless their body mass

Aim: To evaluate the predictive value of Borg’s category ratio-scale (CR-10; 1-10) toward the onset of blood lactate accumulation (OBLA). Methods: 91 young Mexicans performed three non-consecutive sub-maximal exercise tests. Heart rate (HR), blood lactate and oxygen uptake were recorded at each CR-10 rating. Regression equations, reliable HR and CR-10 cut-off points of OBLA were then calculated. Results: HR (86 beats/min) and CR-10 (4.5) predicted OBLA with the same certainty, regardless the subject’s body mass. CR-10, HR and oxygen uptake, independently explained more than 60% of the associated variance to OBLA. Conclusions: CR-10 is useful to predict OBLA with almost the same certainty that HR, regardless the subject’s body mass.

Forces applied at the footrest during ergometer kayaking among female athletes at different competing levels \u2013 a pilot study

BackgroundPower output and force development during exercise are thought to be important indices of performance in elite athletes. The aim of this preliminary study was to determine the forces applied at the footrest during ergometric kayaking in individual kayakers at different competitive levels.MethodsThree elite female kayakers participated voluntarily in the study. Oxygen consumption (VO2) and mean power were measured during paddling at three different work levels (15 W below onset of blood lactate accumulation (OBLA), at OBLA, 15 W above OBLA and all-out paddling) on a modified kayak ergometer. External force sensors were attached to the wires on right and left side connecting the paddle to the flywheel of the kayak ergometer. Individual footrests were built to enable measurements of pushing and pulling forces and to distinguish between the left and right foot.ResultThe relative differences between the three athletes were similar for power, VO2peak and forces at the paddle. There were, however, differences in the forces applied at the footrest, where the most accomplished paddler generated forces 3 to 26 times as high as the least accomplished paddler.ConclusionThe relative differences between the three athletes were similar for power, VO2 and forces at the paddle. There were, however, dramatic differences in the forces applied at the footrest.

Role of lactic acid on cognitive functions

ABSTRACTObjectives: The aim of this research was to establish cognitive changes in relation to blood lactate levels obtained during slow performance of a regimen of exercise sessions.Methods: A total of 15 male professional bodybuilders participated in the study; CrossFit® professionals performed the Workout 15.5, Week 5 Open 2015 consisting of 27-21-15-9 repetitions for time of Row (calories) and Thrusters, with 1-min recovery. Blood lactate, blood glucose, reaction time (RT), execution time of a dual cognitive task, number of errors, and number of omissions were measured at rest, at conclusion of the session, and after recovery for 15 min.Results: The bodybuilders had slightly elevated basal lactate levels than in untrained individuals. The bodybuilders showed significantly increased lactacidemia and decreased RT after completing the training session. Need to define what onset of blood lactate accumulation (OBLA) means.Conclusion: We conclude that bodybuilding fitness regimens lead to an increase in basal lactate levels to 3.16 mmol/L and that acute training sessions can improve attentional performance in relation to lactacidemia, suggesting pro-cognitive effects of a workout.

Influence of Physical Fitness on Special Judo Fitness Test Performance: A Multiple Linear Regression Analysis.

Lopes-Silva, JP, Panissa, VLG, Julio, UF, and Franchini, E. Influence of physical fitness on Special Judo Fitness Test performance: a multiple linear regression analysis. J Strength Cond Res 35(6): 1732-1738, 2021-The purpose of this study was to identify the physical fitness variables that best predict Special Judo Fitness Test (SJFT) performance. Thirty-five male experienced judo athletes took part in this study. All athletes performed 5 tests: upper- and lower-body cycle ergometer graded exercise tests; upper- and lower-body Wingate tests; and SJFT. The peak oxygen consumption (V̇o2peak), maximum heart rate (HRmax), maximum aerobic power, and the variables corresponding to onset blood lactate accumulation (OBLA) were determined during the graded exercise tests. For the Wingate tests, peak power (PP) and mean power were used. Furthermore, the total number of throws, heart rate (HR) immediately and 1 minute after, and SJFT index were calculated. Four separated forward multiple linear regressions (forward model) were used to identify the physical fitness variables that best explained the SJFT variables. Upper-body V̇o2peak (ml·min-1·kg-1) explained 27% of variance in the total number of throws, whereas an additional 7% was explained by upper-body PP. Upper-body HRmax explained 46% of the variance in the HR immediately after the SJFT, whereas lower-body HR at OBLA accounted for an additional 8%. Lower-body HRmax explained 21% of the variance in the HR 1 minute after the SJFT, whereas peak lactate ([La-]peak) after the lower-body graded exercise test accounted for an additional 12%. Upper-body V̇o2peak (ml·min-1·kg-1) alone accounted for 15% of the variance in the SJFT index. Based on these results, the data suggest that physical fitness variables, derived from upper- and lower-body aerobic and anaerobic tests, have a small ability to predict the SJFT variables.

Effects of Repeated-Sprint Training in Hypoxia on Tennis-Specific Performance in Well-Trained Players.

This study examined the physiological, physical and technical responses to repeated-sprint training in normobaric hypoxia [RSH, inspired fraction of oxygen (FiO 2 ) 14.5%] vs. normoxia (RSN, FiO 2 20.9%). Within 12 days, eighteen well-trained tennis players (RSH, n=9 vs. RSN, n=9) completed five specific repeated-sprint sessions that consisted of four sets of 5 maximal shuttle-run sprints. Testing sessions included repeated-sprint ability and Test to Exhaustion Specific to Tennis (TEST). TEST’s maximal duration to exhaustion and time to attain the ‘onset of blood lactate accumulation’ at 4 mMol.L −1 (OBLA) improvements were significantly higher in RSH compared to RSN. Change in time to attain OBLA was concomitant with observations similar in time to the second ventilatory threshold. Significant interaction (P=0.003) was found for ball accuracy with greater increase in RSH (+13.8%, P=0.013) vs. RSN (–4.6%, P=0.15). A correlation (r=0.59, P<0.001) was observed between change in ball accuracy and TEST’s time to exhaustion. Greater improvement in some tennis-specific physical and technical parameters was observed after only 5 sessions of RSH vs. RSN in well-trained tennis players.

Four Weeks of Muscular Endurance Resistance Training Does Not Alter Fatigue Index

Background of Study: The implementation of a muscular endurance resistance training (MERT) program has been shown to be beneficial in augmenting the onset of blood lactate accumulation (OBLA). However, the effects of MERT on local muscular endurance has not been investigated. Objectives: The purposes of the current study were to investigate the effects of 4 weeks of MERT on local muscular endurance, and the relationship between OBLA and fatigue index (FI). Methods: Endurance trained males were randomly designated to either the experimental (EX) or control (CON) group: 9 EX and 8 CON. All participants continued current aerobic training. Baseline measures included OBLA, 1 repetition maximum (1RM) for: leg press (LP), leg curl (LC), and leg extension (LE). FI of the quadriceps was assessed via a dynamometer and the Thorstesson protocol. In addition, the EX group performed supervised MERT training for four weeks. A two way ANOVA was used to assess group and time differences in performance measures. The relationship between OBLA and FI was assessed using Pearson’s Correlation. Results: No significant group differences were observed in all baseline measurements (p&gt;0.05). There were no significant group or time differences for OBLA and FI (p&gt;0.05). Pearson’s correlation revealed no significant relationship (p&gt;0.05, r=&lt;0.01) existed between FI and OBLA. Conclusions: It was observed that four weeks of MERT provided an insufficient stimulus to improve OBLA and FI, and no significant relationship existed between OBLA and FI. Athletes using MERT should include additional mesocycles for favorable adaptations to local muscular endurance and OBLA.

The Validity of External:Internal Training Load Ratios in Rested and Fatigued Soccer Players.

Purpose: To examine the relationship of external:internal training load ratios with fitness and assess the impact of fatigue. Method: Ten soccer players performed a lactate threshold test followed by two soccer simulations (BEAST90mod) 48 h apart. Recovery (TQR) and muscle soreness (DOMS) was measured before each trial. Internal Training load (TL) (iTRIMP) and external load total distance (TD), high intensity distance (HID), PlayerLoad™ (PL) mean metabolic power (MMP) high metabolic power distance (HP) were collected for each trial and external:internal ratios produced. The relationships between ratios and velocity at lactate threshold (vLT) and velocity at Onset of Blood Lactate Accumulation (vOBLA) were examined in both trials along with changes in ratios. Results: Total Quality of Recovery and DOMS showed large changes. There were trivial to large decreases in TL from trial 1 to 2. Moderate increases in ratios for TD:iTRIMP, PL:iTRIMP and MMP:iTRIMP were seen but only small/trivial for HP:iTRIMP and HID:iTRIMP. In rested conditions all ratios show large relationships with vLT and vOBLA. However vLT vs. HID:iTRIMP; PL:iTRIMP; HP:iTRIMP and vOBLA vs. TD:iTRIMP; PL:iTRIMP; MMP:iTRIMP became weaker under fatigue. Conclusions: Acute changes in the ratios have implications forthe use of ratios as fitness measures but also as indicators of fatigue.

Aerobic Exercise Supplemented With Muscular Endurance Training Improves Onset of Blood Lactate Accumulation.

Farrell III, JW, Lantis, DJ, Ade, CJ, Cantrell, GS, and Larson, RD. Aerobic exercise supplemented with muscular endurance training improves onset of blood lactate accumulation. J Strength Cond Res 32(5): 1376-1382, 2018-Studies have shown that when aerobic exercise is supplemented with muscular endurance training metabolic adaptions occur that result in the delay of the onset of blood lactate accumulation (OBLA). However, previous studies have not explored any submaximal cardiorespiratory adaptations that may result from this training protocol. The aim of the current investigation was to evaluate the effect of supplementing an aerobic exercise training program with a muscular endurance training program on various cardiorespiratory and metabolic measurements. Fourteen aerobically active men performed an incremental exercise test to determine the OBLA, gas exchange threshold (GET), and maximal oxygen uptake (V[Combining Dot Above]O2max). Maximal strength was measured using 1 repetition maximum (1RM) for leg press (LP), leg curl (LC), and leg extension (LE). Eight subjects supplemented their aerobic activity (experimental [EX] group) with 8 weeks of muscular endurance training, while 6 continued their regular aerobic activity (control [CON] group). No significant group differences were observed for all pretraining variables. After 8 weeks of training, no significant differences in body mass, GET, and V[Combining Dot Above]O2max were observed for either group. However, the EX group showed a significant improvement for both absolute and relative V[Combining Dot Above]O2 at OBLA compared with the CON group. Leg curl and LE 1RM assessments for the EX group showed a significant improvement compared with CON group. Muscular endurance training did not improve GET and V[Combining Dot Above]O2max, but significantly increased V[Combining Dot Above]O2 at OBLA, LP, and LC. These findings suggest that this training protocol maybe useful in the development of submaximal aerobic performance and leg strength for endurance athletes.

Comparison of Three Lactate Threshold Determination METHODS in Trained Cyclists and in Non-Cyclists

While lactate threshold (LT) is a common laboratory test and is often used to design training plans and monitor fitness changes, there is no consensus as to which determination method should be used. Three of the most common are the break point (BREAK), 1 mmol.L-1 over baseline (+1 mmol), and reaching 4 mmol.L-1 (onset of blood lactate accumulation, OBLA). Currently, it is not clear if different determination methods could yield varying results in different populations. PURPOSE: We compared 3 most commonly used LT methods in trained cyclists and in athletes (soccer players) who were not accustomed to cycling exercise. We hypothesized that the BREAK and +1 mmol methods would yield similar results in both populations. METHODS: LT data were analyzed from 41 athletes [18 trained cyclists (15 males [m], 3 females [f]) and 23 female soccer players]. Tests were performed on a cycle ergometer using 5 min stages starting at 70 W (m)/50 W (f). Work rates were increased by 25 W (m)/15 W (f) for the first 3-4 stages, and by 15 W (m)/10 W (f) for the last 2-3 stages. Blood samples were obtained in the last min of each stage, and blood lactate was analyzed using a Lactate Plus device. For determinations of LT, 3 trained investigators independently analyzed the plots. RESULTS: In cyclists, LTs using BREAK and +1 mmol (247±48 W vs. 250±50 W, p=0.52) were not different but were significantly lower than that obtained with OBLA (270±54 W). Correlational analyses indicate that LT using BREAK and +1 mmol were strongly related (R=0.99). Associations were strong between +1 mmol and OBLA (R=0.96) and between BREAK and OBLA (R=0.96). In non-cyclists, LTs obtained with all 3 methods were significantly different (BREAK: 125±13 W; +1 mmol: 130±11 W; OBLA, 134±13 W; all p<0.04), although BREAK and +1 mmol were strongly associated (R=0.98). The associations between different LT methods were much weaker in non-cyclists (1 mmol and OBLA: R=0.90; BREAK and OBLA: R=0.85) compared with cyclists. CONCLUSIONS: Break point and +1 mmol.L-1 methods yield comparable results in trained cyclists but not in non-cyclists. Caution should be used when interpreting LT results obtained from different determination methods.

The effects of concurrent visual feedback on the control of swimming intensities above the onset of blood lactate accumulation

PurposeEffective control of swimming speed can increase training effectiveness and therefore enhance training adaptations. The aim of the present study was to investigate the effects of concurrent visual feedback on swimming speed at an exercise intensity above the onset of blood lactate accumulation (OBLA).MethodsThe study involved 12 healthy male and female swim team members. The participants executed two 200-m freestyle trials within an individually predetermined swim time matching an exercise intensity above OBLA (exercise zone 4). In one trial, no additional information was provided, whereas concurrent visual feedback was given on swimming speed in the other.ResultsConcurrent visual feedback narrowed the discrepancy between the predetermined and obtained swimming times (&lt;i&gt;p&lt;/i&gt; &lt; 0.001). This improvement in swimming time (accuracy) showed a negative correlation with the increase in post-trial lactate concentration. The correlation between the difference in the predetermined and obtained times and the increase in lactate was &lt;i&gt;R&lt;/i&gt; = –0.46 when no visual feedback was provided but &lt;i&gt;R&lt;/i&gt; = –0.64 with visual feedback, with the latter result statistically significant (&lt;i&gt;p&lt;/i&gt; = 0.024).ConclusionsConcurrent visual feedback allows swimmers to consistently maintain a predetermined swimming speed and therefore keep the specified exercise intensity as evidenced by the increase in lactate concentration. This can result in more effective execution of training goals and thereby enhance training outcomes.

Physiological characteristics and performance in elite enduro mountain biking.

Enduro mountain bike racing is composed of several timed predominantly downhill race stages linked by time restricted, non-competitive transition stages. This study aimed to 1) detail and compare the laboratory assessed physiological characteristics of elite and non-elite enduro mountain bike riders, and 2) evaluate the use of 10Hz global positioning systems (GPS) unit including a 100Hz triaxial accelerometer to define the demands of enduro mountain bike racing and identify components of successful performance. Eleven (n=11) male enduro mountain bike riders completed laboratory protocols for peak aerobic capacity (VO2peak), onset of blood lactate accumulation at 2 and 4 mmol/L (OBLA2 and OBLA4 respectively), intermittent sprint test (EST), and anthropometry measures. Participants were divided into elite (n=5) and non-elite (n=6) groups for analysis. Nine (n=9) elite enduro mountain bike athletes participated in field data collection at an international enduro mountain bike race. Two race stages were used for analysis of velocity, accumulated load, heart rate and time to complete specific sections of track calculated from GPS units placed on the bicycle seat mast and the rider’s torso. Elite athletes produced greater power during the EST and at VO2peak, OBLA2, OBLA4 when compared to non-elite riders (all p&lt;0.05) with no significant differences in anthropometry (p&gt;0.05). Accumulated load was significantly greater on the bicycle than the rider on both stages (p&lt;0.05) and accumulated load in both locations was significantly higher during stage two compared to stage 1 reflecting differences in terrain (p&lt;0.05). GPS analysis allowed detailed analysis of performance showing winning performances were characterised by reduced time to complete technical downhill and non-technical climbing sections during stage one and technical downhill sections only during stage two. In conclusion, successful performance in enduro mountain bike racing requires adequate skill and technique to sustain high velocities over technical terrain coupled with large aerobic and anaerobic capacities.

Accuracy of a Modified Lactate Minimum Test and Reverse Lactate Threshold Test to Determine Maximal Lactate Steady State

Wahl, P, Manunzio, C, Vogt, F, Strütt, S, Volmary, P, Bloch, W, and Mester, J. Accuracy of a modified lactate minimum test and reverse lactate threshold test to determine maximal lactate steady state. J Strength Cond Res 31(12): 3489-3496, 2017-This study evaluated the accuracy of a modified lactate minimum test (mLMT), a modified reverse lactate threshold test (mRLT), compared with 2 established threshold concepts (onset of blood lactate accumulation [OBLA] and modified maximal deviation method [mDmax]) to determine power output at maximal lactate steady state (MLSS) in cycling. Nineteen subjects performed an mLMT, mRLT, graded exercise test (100 W start, +20 W every 3 minutes) and 3 or more constant-load tests of 30 minutes to determine power output at MLSS. The mLMT and mRLT both consisted of an initial lactate priming segment, followed by a short recovery phase. Afterward, the initial load of the subsequent incremental or reverse segment was calculated individually and was increased or decreased by 10 W every 90 seconds, respectively. The mean difference to MLSS was +2 ± 7 W (mLMT), +5 ± 10 W (mRLT), +9 ± 21 W (OBLA), and +6 ± 14 W (mDmax). The correlation between power output at MLSS and mLMT was highest (r = 0.99), followed by mRLT (r = 0.98), mDmax (r = 0.95), and OBLA (r = 0.90). Because of the higher accuracy of the mLMT and the mRLT to determine MLSS compared with OBLA and mDmax, we suggest both tests as valid and meaningful concepts to estimate power output at MLSS in one single test in moderately trained to well-trained athletes. Additionally, our modified tests provide anaerobic data and do not require detailed knowledge of the subjects' training status compared with previous LMT or RLT protocols.