Anaerobic Contribution Research Articles

Energy System Contribution during 1500M Running in Untrained and Endurance-Trained Asian Male College Students

OBJECTIVES To compare the aerobic and anaerobic energy system contribution during 1500m running between collegiate untrained (UT) and endurance trained (ET) subjects.METHODS Five Asian UT (age: 23.8 ± 0.4 yrs, body fat %: 15.9 ± 5.7 %, height: 174.0 ± 4.1 cm, weight: 65.5 ± 4.1 kg) and 5 Asian ET male participants (age: 24.4 ± 3.9 yrs, body fat %: 12.9 ± 6.9 %, height: 169.4 ± 5.1 cm, weight: 60.6 ± 8.1 kg) participated in this study. Participants attended 3 sessions to determine their body composition, submaximal and maximal oxygen consumption (VO2max) test, 1500m track running session (RS) and 1500m treadmill RS. The maximally accumulated oxygen deficit (MAOD) method was used to calculate energy system contribution.RESULTS The times for the 1500m track run for the UT and ET were 428.0 ± 48.7 and 331.6 ± 14.0 seconds (p=0.004) respectively. There were no significant differences in VO2 between the 1500m track and treadmill RS indicating the participants ran to their personal best times for both trials. The mean VO2max(mL•kg-1•min-1) were significantly different between UT (45.1 ± 5.0) and ET participants (58.3 ± 2.2) (p=0.002). The mean relative contributions of the aerobic and anaerobic energy system during 1500m running were significantly different for the UT, 65.4 ± 7.0%, 34.6 ± 7.0 and ET, 75.7 ± 1.5%, 24.3 ± 1.5 % (p =0.011).CONCLUSIONS The point of equal contribution of the aerobic and the anaerobic systems occurred after thirty to forty seconds of intensive exhaustive running after which the aerobic contribution continues to increase while the anaerobic contribution decreases with increasing duration. By the end of 60th second of exhaustive running, the ET mean aerobic contribution is 71.5% compared to the UT’s 58.6%. This finding suggests a greater reliance on the aerobic energy system by the ET.

Applicability of Maximal Ergometer Testing and Sprint Performance in Adolescent Endurance and Sprint Trained Swimmers.

Sprint swimming is a short duration, high intensity sport requiring a relatively greater contribution of energy from anaerobic metabolism. Understanding energy system utilization for the classification of a competitive swimmer (sprint or distance) may be useful for both training prescription and event specialization. The relationship between anaerobic swim ergometer testing and adolescent sprint swimming performance has not been investigated. The purpose of this study was to compare the performance and physiological responses during a maximal all-out ergometer test as well as the maximal anaerobic lactate test in a group of sprint vs. middle-distance specialized swimmers. Sixteen (n = 16) competitive swimmers (mean ± standard deviation (SD), age 16.8 ± 0.7 year; body mass 67.3 ± 9.8 kg) were categorized into two gender matched groups: sprint (n = 8) and middle-distance (n = 8). Each athlete performed (1) a 45 s swim ergometer maximal test to determine peak and mean power output (Watts (W)), (2) a MANLT test to determine peak and average velocity as well as the post-exercise lactate response, and (3) a 50 m swim time trial. The sprint group showed a higher mean (p = 0.026) and peak (p = 0.031) velocity during the MANLT. In addition, blood lactate concentration was significantly (p < 0.01) higher in the sprint vs. middle-distance trained group at 3 and 12 min after completion of the MANLT (3-min post 11.29 ± 2.32 vs. 9.55 ± 3.48 mmol/L; 12-min post 8.23 ± 2.28 vs. 7.05 ± 2.47 mmol/L). The power output during the 45 s all-out swimming ergometer test was higher in the sprint trained group. The results of this study demonstrate the anaerobic contribution to sprint swimming measured during an all-out dryland ergometer test.

Metabolic Profiles of the 30-15 Intermittent Fitness Test and the Corresponding Continuous Version in Team-Sport Athletes-Elucidating the Role of Inter-Effort Recovery.

To elucidate the role of inter-effort recovery in shuttle running by comparing the metabolic profiles of the 30-15 Intermittent Fitness Test (30-15IFT) and the corresponding continuous version (30-15IFT-CONT). Sixteen state-level handball players (age = 23 [3]y, height = 185 [7]cm, weight = 85 [14]kg) completed the 30-15IFT and 30-15IFT-CONT, and speed at the last completed stage (in kilometers per hour) and time to exhaustion (in seconds) were assessed. Furthermore, oxygen uptake (in milliliters per kilogram per minute) and blood lactate were obtained preexercise, during exercise, and until 15minutes postexercise. Metabolic energy (in kilojoules), metabolic power (in Watts per kilogram), and relative (in percentage) energy contribution of the aerobic (WAER, WAERint), anaerobic lactic (WBLC, WBLCint), and anaerobic alactic (WPCr, WPCrint) systems were calculated by PCr-La-O2 method for 30-15IFT-CONT and 30-15IFT. No difference in peak oxygen uptake was found between 30-15IFT and 30-15IFT-CONT (60.6 [6.6] vs 60.5 [5.1]mL·kg-1·min-1, P = .165, d = 0.20), whereas speed at the last completed stage was higher in 30-15IFT (18.3 [1.4] vs 16.1 [1.0]km·h-1, P < .001, d = 1.17). Metabolic energy was also higher in 30-15IFT (1224.2 [269.6] vs 772.8 [63.1]kJ, P < .001, d = 5.60), and metabolic profiles differed substantially for aerobic (30-15IFT = 67.2 [5.2] vs 30-15IFT-CONT = 85.2% [2.5%], P < .001, d = -4.01), anaerobic lactic (30-15IFT = 4.4 [1.4] vs 30-15IFT-CONT = 6.2% [1.8%], P < .001, d = -1.04), and anaerobic alactic (30-15IFT = 28.4 [4.7] vs 30-15IFT-CONT = 8.6% [2.1%], P < .001, d = 5.43) components. Both 30-15IFT and 30-15IFT-CONT are mainly fueled by aerobic energy, but their metabolic profiles differ substantially in both aerobic and anaerobic alactic energy contribution. Due to the presence of inter-effort recovery, intermittent shuttle runs rely to a higher extent on anaerobic alactic energy and a fast, aerobic replenishment of PCr during the short breaks between shuttles.

High-Intensity Warm-Up Increases Anaerobic Energy Contribution during 100-m Sprint.

Simple SummaryCertain exercise performances or movements cause sudden changes (or increases) in metabolic response. Track and field running events that require explosive energy in the shortest time, such as a 100-m sprint, need an immediate energy supply. Referring to the relevant studies to date, metabolic responses to submaximal exercise have been well documented, while information on the metabolic responses of short-term sprint performance is relatively insufficient. In this regard, based on the evidence that the human body relies on anaerobic energy metabolism during intense, short-term exercise, we investigated anaerobic energy contributions following the acute effect of a high-intensity warm-up during a 100 m-sprint. The main finding of our study revealed that a high-intensity warm-up (HIW) increases the contribution of the anaerobic system, probably by activating key regulatory enzymes related to anaerobic energy metabolism, compared to a low-intensity warm-up, for a 100-m sprint. Therefore, an HIW is effective in increasing anaerobic energy contribution during a 100-m sprint, which can be a useful strategy for coaches and athletes in the field.This study aimed to evaluate the effects of warm-up intensity on energetic contribution and performance during a 100-m sprint. Ten young male sprinters performed 100-m sprints following both a high-intensity warm-up (HIW) and a low-intensity warm-up (LIW). Both the HIW and LIW were included in common baseline warm-ups and interventional warm-ups (eight 60-m runs, HIW; 60 to 95%, LIW; 40% alone). Blood lactate concentration [La−], time trial, and oxygen uptake (VO2) were measured. The different energy system contribution was calculated by using physiological variables. [La−1]Max following HIW was significantly higher than in LIW (11.86 ± 2.52 vs. 9.24 ± 1.61 mmol·L−1; p < 0.01, respectively). The 100-m sprint time trial was not significantly different between HIW and LIW (11.83 ± 0.57 vs. 12.10 ± 0.63 s; p > 0.05, respectively). The relative (%) phosphagen system contribution was higher in the HIW compared to the LIW (70 vs. 61%; p < 0.01, respectively). These results indicate that an HIW increases phosphagen and glycolytic system contributions as compared to an LIW for the 100-m sprint. Furthermore, an HIW prior to short-term intense exercise has no effect on a 100-m sprint time trial; however, it tends to improve times (decreased 100-m time trial; −0.27 s in HIW vs. LIW).

Determinant physiological factors of simulated BMX race

Evaluating the physiological demands of BMX cycling on a track provides coaches with the information required to prescribe more effective training programmes. To determine the relative importance of physiological factors during simulated BMX race, 12 male riders (age 19.2 ± 3.5 years, height 1.76 ± 0.06 m, mass 68.5 ± 4.3 kg) completed a maximum aerobic capacity (V̇O2max) test in a laboratory, and a week later, completed six laps on a BMX track interspersed by 15 min passive recovery. Peak power, immediate post-lap V̇O2peak, blood lactate, and heart rate were measured in each lap. Peak power to weight ratio was significantly correlated with lap time, however, the strength of this association decreased in each subsequent lap. Mean V̇O2peak was greater than 80% of laboratory-measured V̇O2max in every lap, indicating a strong contribution of the aerobic energy system during BMX racing. This study also identified that mean blood lactate was significantly associated with lap time, which showed the importance of the anaerobic energy system contribution to BMX race. Despite the short period of pedalling during BMX racing, both aerobic and anaerobic energy systems are important contributors to lap performance. Coaches should consider maximising both anaerobic power and aerobic capacity to improve riders’ overall performance in multiple laps.

Energy contributions in swimmers with physical impairments in an all-out 200-m front crawl test

In competitive swimming, performance is associated with swimming a certain distance in the shortest possible time. Specifically, in an all-out 200-m front crawl test (T200), the intensity and duration of effort represent a challenge for coaches and swimmers to balance swimming speed with the ability to use different energy sources (aerobic and anaerobic) with lower energy cost (C). In the case of swimmers with physical impairments, physiological parameters are still little explored, and their monitoring may allow a better understanding of performance. The aim of this study was to assess the total metabolic energetic contribution (Etot) and C of swimmers with physical impairments in a T200. Eleven swimmers (7 males and 4 females; age: 32.3 ± 12.3 years) with physical impairments performed a T200 with the use of a snorkel and respiratory valve system. Measurements were performed for peak oxygen uptake (VO2peak), blood lactate concentration (La), Etot and C. The performance was 210.2 ± 48.1 s (swimming speed 0.99 ± 0.14im·s−1). The aerobic, anaerobic lactic and anaerobic alactic contributions were 70.1%, 17.1% and 12.8%, respectively. C was 1.22 ± 0.52 kJ m−1. Swimmers with physical impairment of different sport classes presented, predominately, high aerobic metabolism contribution to the Etot and different values of C, with a certain tendency of C being lower in those faster swimmers than in slower swimmers. Possible divergences in this trend seem to be explained by the different competitive levels, body position and upper limb impairment.

Does caffeine supplementation alter energy contribution during a work-based ~30 min cycling time-trial?

Caffeine has been shown to increase anaerobic energy contribution during short-duration cycling time-trials (TT) though no information exists on whether caffeine alters energy contribution during more prolonged, aerobic type TTs. The aim of this study was to determine the effects of caffeine supplementation on longer and predominantly aerobic exercise. Fifteen recreationally-trained male cyclists (age 38±8 y, height 1.76±0.07 m, body mass 72.9±7.7 kg) performed a ~30 min cycling TT following either 6 mg·kg-1BM caffeine (CAF) or placebo (PLA) supplementation, and one control (CON) session without supplementation, in a double- -blind, randomised, counterbalance and cross-over design. Mean power output (MPO) was recorded as the outcome measure. Respiratory values were measured throughout exercise for the determination of energy system contribution. Data were analysed using mixed-models. CAF improved mean MPO compared to CON (P=0.01), and a trend towards an improvement compared to PLA (P=0.07); there was no difference in MPO at any timepoint throughout the exercise between conditions. There was a main effect of Condition (P=0.04) and Time (P&lt;0.0001) on blood lactate concentration, which tended to be higher in CAF vs. both PLA and CON (Condition effect, both P=0.07). Ratings of perceived exertion increased over time (P&lt;0.0001), with no effect of Condition or interaction (both P&gt;0.05). Glycolytic energy contribution was increased in CAF compared to CON and PLA (both P&lt;0.05), but not aerobic or ATP-CP (both P&gt;0.05). CAF improved aerobic TT performance compared to CON, which could be explained by increased glycolytic energy contribution.

Effect of racetrack surface on glycolytic activity of trained endurance horses

ABSTRACT No study has analysed the effects of wet and dry racetrack surface on the glycolytic activity of Arabian horses. The aim of the present study was to investigate the effects of wet and dry racetrack surfaces during a riding test in an Arabian endurance horse. Using a counterbalanced design, nine healthy and trained mixed-bred Arabian horses performed a single-step riding test on a wet (compacted sand) or dry (uncompacted sand) racetrack surface. The wet racetrack received a daily wetting and was compacted using a tractor, while the dry racetrack was upturned by a tractor daily. Both racetracks were elliptical with straight lines of 600 m and total length around 900 metres. Blood samples were drawn from the jugular vein, immediately after the end of the test, and used for the analysis of blood lactate concentration. Mean blood lactate concentration was significantly higher after the riding test on the dry racetrack (2.6 ± 1.6 mmol/L) compared with wet racetrack (0.9 ± 0.3 mmol/L) surface (p = 0.007; d = 1.48, [large]; 95%CI = 0.37–2.44). In conclusion, dry racetrack surface increases lactic anaerobic contribution in trained Arabian horses during a single-step riding test in the field.

Does caffeine supplementation alter energy contribution during a work-based ~30 min cycling time-trial?

Caffeine has been shown to increase anaerobic energy contribution during short-duration cycling time-trials (TT) though no information exists on whether caffeine alters energy contribution during more prolonged, aerobic type TTs. The aim of this study was to determine the effects of caffeine supplementation on longer and predominantly aerobic exercise. Fifteen recreationally-trained male cyclists (age 38±8 y, height 1.76±0.07 m, body mass 72.9±7.7 kg) performed a ~30 min cycling TT following either 6 mg·kg-1BM caffeine (CAF) or placebo (PLA) supplementation, and one control (CON) session without supplementation, in a double- -blind, randomised, counterbalance and cross-over design. Mean power output (MPO) was recorded as the outcome measure. Respiratory values were measured throughout exercise for the determination of energy system contribution. Data were analysed using mixed-models. CAF improved mean MPO compared to CON (P=0.01), and a trend towards an improvement compared to PLA (P=0.07); there was no difference in MPO at any timepoint throughout the exercise between conditions. There was a main effect of Condition (P=0.04) and Time (P&lt;0.0001) on blood lactate concentration, which tended to be higher in CAF vs. both PLA and CON (Condition effect, both P=0.07). Ratings of perceived exertion increased over time (P&lt;0.0001), with no effect of Condition or interaction (both P&gt;0.05). Glycolytic energy contribution was increased in CAF compared to CON and PLA (both P&lt;0.05), but not aerobic or ATP-CP (both P&gt;0.05). CAF improved aerobic TT performance compared to CON, which could be explained by increased glycolytic energy contribution.

Metabolic load comparison between the quarters of a game in elite male basketball players using sport metabolomics

Purpose: A basketball match is characterized by intermittent high-intensity activities, thereby relying extensively on both aerobic and anaerobic metabolic pathways. Here, we aimed to compare the metabolic fluctuations between the four 10-min quarters of high-level basketball games using metabolomics analyses. Methods: 70 male basketball players with at least 3 years of experience in the Iran national top-league participated. Before and after each quarter, saliva samples were taken for subsequent untargeted metabolomics analyses, where Principal component analysis (PCA) and Partial least squares-discriminant analysis (PLS-DA) were employed for statistical analysis. Results: Quarters 1 and 3 showed similar metabolic profiles, with increased levels of ATP turnover (higher Lactate, Pyruvate, Succinic Acid, Citric Cid, Glucose and Hypoxanthine), indicating more reliance on anaerobic energy systems than quarters 2 and 4. In comparison, quarters 2 and 4 showed a reduction in Valine and Lucien and an increase in Alanine, Glycerol, AcetoAcetic Acid, Acetone, Succinic Acid, Citric Acid, Acetate and Taurine that was not present in quarters 1 and 3, indicating greater reliance of aerobic energy contribution, fat metabolism and gluconeogenesis. Conclusion: Our data demonstrate that the higher intensity of movements in the first quarter, where players are more rested, induce an increase in anaerobic energy contribution. This seems to be the case also for the third quarter that follows 15 min of rest, whereas the accumulated fatigue and reduction of high-intensity movements in the second and fourth quarters also reduces the speed of energy production and players thereby utilize more aerobic energy.

Cycling Performance Enhancement After Drop Jumps May Be Attributed to Postactivation Potentiation and Increased Anaerobic Capacity.

de Poli, RAB, Boullosa, DA, Malta, ES, Behm, D, Lopes, VHF, Barbieri, FA, and Zagatto, AM. Cycling performance enhancement after drop jumps may be attributed to postactivation potentiation and increased anaerobic capacity. J Strength Cond Res 34(9): 2465-2475, 2020-The study aimed to investigate the effects of drop jumps (DJs) on supramaximal cycling performance, anaerobic capacity (AC), electromyography, and fatigue. Thirty-eight recreational cyclists participated into 3 independent studies. In study 1 (n = 14), neuromuscular fatigue was assessed with the twitch interpolation technique. In study 2 (n = 16), the AC and metabolic contributions were measured with the maximal accumulated oxygen deficit method and the sum of the glycolytic and phosphagen pathways. In study 3 (n = 8), postactivation potentiation (PAP) induced by repeated DJs was evaluated. The DJ protocol was effective for significantly improving cycling performance by +9.8 and +7.4% in studies 1 and 2, respectively (p ≤ 0.05). No differences were observed in electromyography between conditions (p = 0.70); however, the force evoked by a doublet at low (10 Hz) and high frequencies (100 Hz) declined for control (-16.4 and -23.9%) and DJ protocols (-18.6 and -26.9%) (p < 0.01). Force decline was greater in the DJ condition (p < 0.03). Anaerobic capacity and glycolytic pathway contributions were +7.7 and +9.1% higher after DJ protocol (p = 0.01). Peak force during maximal voluntary contraction (+5.6%) and doublet evoked force at 100 Hz (+5.0%) were higher after DJs. The DJ protocol induced PAP, improved supramaximal cycling performance, and increased AC despite higher peripheral fatigue.

Physiological Responses And Energetic Of Two Sprint Interval Exercise Protocols Based On Rope-skipping And Cycling

High-intensity interval training could improve performance effectively. However, the acute physiological response and energy expenditure of a low-volume, high-intensity rope-skipping based protocol have not been determined. PURPOSE: To compare the physiological response and energy resource in repeated bouts of sprint interval cycling (SIC) and high-intensity intermittent double-under rope skipping (HIT-RS). METHOD: Fifteen college students (age=20.2±0.8yrs, body mass=67.7±4.8kg, BMI=22.4±1.2kg.m-2, VO2peak=51.90±7.83ml.kg-1.min-1) volunteered for this study. Participants completed two protocols (4⊆30s with 4min active recovery) on separate days with 1 week between trials. VO2 and heart rate were monitored at rest, during test and continue to 1 hour after test. Blood lactate was measured 3 minutes after each bout, and minute by minute after the last bout. Lactic (WBla) and alactic anaerobic (WPCr) energy outputs were calculated from net lactate production and the fast component of EPOC. Aerobic metabolism (Waer) was determined from VO2 during exercise. RESULT: Mean values for %VO2peak and %HRpeak for SIC (78.79±15.35% and 85.33±4.69%) and HIT-RS (74.93±16.21% and 83.17±5.37%) were not significantly different (p>0.05). The overall energy cost for SIC (102.75±13.15 kJ) was significantly higher (p<0.001) compared to HIT-RS (70.86±10.25 kJ). Waer, WBla and WPCr for SIC (17.39±3.08, 59.50±8.10 and 25.86±5.40 kJ) and HIT-RS (13.05±2.01, 27.97±6.77 and 29.84±6.28 kJ) were significantly different (p<0.01). Fractions of Waer, WBla and WPCr for SIC (16.92±1.77%, 57.99±4.70% and 25.09±3.65%) and HIT-RS (18.80±3.13%, 38.84±6.09% and 42.36±5.98%) were significantly different (p<0.001). Both protocols were anaerobic-dominated with similar fraction (SIC:83.08±3.01% vs HIT-RS: 81.20±4.52%). Compared to SIC, HIT-RS was more PCr dominant (42.36±5.98% vs 25.09±3.65%, p<0.01) with lower anaerobic lactic contribution (38.84±6.09% vs 57.99±4.70%, p<0.001). CONCLUSION: High-intensity interval protocol of rope skipping elicits vigorous cardiorespiratory responses and may confer physiological adaptations and performance improvements resembling as SIC.

Methods For Estimating Anaerobic Glycolytic Capacity (vLa Max ) In Trained Cyclists

PURPOSE: The maximum rate of lactate production (vLaMax) can be used to estimate the maximum anaerobic energy contribution, which can be used to optimize endurance training. The aim of this study was to examine the reliability of a 20-sec vLaMax estimate using either a variable or standardized alactic time interval (talac). METHODS: 16 trained male cyclists and triathletes (35.3 + 8.9 yo, 1.80 + 0.05 m, and 73.3 + 11.2 kg, average 30-sec Wingate power of 9.0 +1.6 W.kg-1) were recruited. Subjects completed two familiarization trials on their own before completing two 20-sec maximal sprints on their own bikes which were attached to a Wahoo Kickr trainer. Each session began with a 10-min warm-up at 100 W before each sprint and were then followed by 12-min passive rest. A lactate (HLa) sample was taken from the finger at the end of the sprint and then every 2-min after that until HLa dropped > 1 mM. vLaMax was then calculated using (HLa post - pre)/(20-sec - alactic time), where talac was either time 0-sec to time where power drops 3.5%, or was set at 5-sec. RESULTS: Individual sprint sessions data were analyzed and no significant differences (p>0.05) nor were noted between session 1 and 2 data; all data were pooled and then vLaMax calculated using methods described above. Mean 20-sec sprint power was 9.8 + 1.0 W.kg-1 (~109% of Wingate) and a total work of 14.5 + 2.7. The talac was calculated to be 4.0 + 2.3-sec. There was no significant difference (p>0.05) between the calculated vLaMax 0.51 + 0.18 mM.L-1.sec-1 and vLaMax using the a standard 5-sec value, 0.54 + 0.15 mM.L-1.sec-1. Neither vLaMax value appears to be associated (r2 < 0.10, p>0.05) with absolute sprint performance. CONCLUSIONS: These results indicate that using a standard talac of 5-sec produced similar results as calculating it using a 3.5% drop in power. While vLaMax may ultimately influence HLa testing curves (i.e., lactate threshold) and endurance performance, it does not appear to be associated with actual sprint power output.

Metabolic And Hemodynamic Responses To High Intensity Interval Training With Various Recovery Intervals

For more than twenty years, the Tabata protocol has provided the basis for high intensity interval training (HIIT). Although the improvements associated with the protocol are laudable, an intensity of 170% of max VO2, is difficult for even highly motivated athletes to achieve. A repeated bout HIIT protocol at 100% of Max VO2 may be a more tolerable option, if it achieves a similar metabolic stress. PURPOSE: The purpose was to determine the metabolic cost of 8 repetitions of HIIT at a workload equivalent to 100% Max VO2 (HIIT) for 20 sec with recovery intervals of 10, 20, 30 and 40 sec at 20% of Max VO2. METHODS: 14 recreationally active college-age students (age: 21.6±1.1 yrs., height: 171.410.5 cm, body mass: 75.0±10.6 kg, max VO2 2.89±.67, 8 ♂) volunteered to participate in a randomized, single-blind crossover design study with a minimum of 4 days between trials. A max VO2 ramp protocol on a Lode Cycle ergometer preceded the HIIT trials and established the max workload. VO2 was obtained by continuous open circuit spirometry and blood lactate by finger puncture. Excess Post Exercise O2 Consumption (EPOC) was obtained for 20 min. RESULTS: Statistical analysis by ANOVA with repeated measures (P<.05) was applied to the following data.CONCLUSION: The prescribed HIIT work intervals provide ample metabolic stimulus, however recovery intervals in excess of 30 seconds substantially attenuate the oxygen uptake, while still requiring a strong anaerobic contribution. The use of eight repeat bouts of HIIT at a workload equivalent to 100% of max VO2 may be a viable alternative to the traditional Tabata protocol.

Changes in energy system contributions to the Wingate anaerobic test in climbers after a high altitude expedition.

The Wingate anaerobic test measures the maximum anaerobic capacity of the lower limbs. The energy sources of Wingate test are dominated by anaerobic metabolism (~ 80%). Chronic high altitude exposure induces adaptations on skeletal muscle function and metabolism. Therefore, the study aim was to investigate possible changes in the energy system contribution to Wingate test before and after a high-altitude sojourn. Seven male climbers performed a Wingate test before and after a 43-day expedition in the Himalaya (23days above 5.000m). Mechanical parameters included: peak power (PP), average power (AP), minimum power (MP) and fatigue index (FI). The metabolic equivalents were calculated as aerobic contribution from O2 uptake during the 30-s exercise phase (WVO2), lactic and alactic anaerobic energy sources were determined from net lactate production (WLa) and the fast component of the kinetics of post-exercise oxygen uptake (WPCr), respectively. The total metabolic work (WTOT) was calculated as the sum of the three energy sources. PP and AP decreased from 7.3 ± 1.1 to 6.7 ± 1.1W/kg and from 5.9 ± 0.7 to 5.4 ± 0.8W/kg, respectively, while FI was unchanged. WTOT declined from 103.9 ± 28.7 to 83.8 ± 17.8kJ. Relative aerobic contribution remained unchanged (19.9 ± 4.8% vs 18.3 ± 2.3%), while anaerobic lactic and alactic contributions decreased from 48.3 ± 11.7 to 43.1 ± 8.9% and increased from 31.8 ± 14.5 to 38.6 ± 7.4%, respectively. Chronic high altitude exposure induced a reduction in both mechanical and metabolic parameters of Wingate test. The anaerobic alactic relative contribution increased while the anaerobic lactic decreased, leaving unaffected the overall relative anaerobic contribution to Wingate test.

Multi-ingredient pre-workout supplementation changes energy system contribution and improves performance during high-intensity intermittent exercise in physically active individuals: a double-blind and placebo controlled study

BackgroundNutritional ergogenic aids are commonly used to boost physiological adaptations to exercise and promote greater fitness gains. However, there is a paucity of data about multi-ingredient pre-workout supplementation (MIPS). Therefore, the aim of the present study was to investigate the acute effects of MIPS on the oxidative, glycolytic and ATP-CP energy systems contribution, time spent above 90% V̇O2max (T90% V̇O2max), excess post-exercise oxygen consumption (EPOC) magnitude, number of efforts and time to exhaustion during a high-intensity interval exercise (HIIE) session.MethodsTwelve physically-active and healthy men completed the HIIE sessions that involved running bouts of 15 s on the treadmill at 120% of the maximum aerobic speed (MAS), interspersed with 15 s of passive recovery. Blood lactate was collected at immediately post, 3, 5, and 7 min post exercise. The contribution of ATP-CP, glycolytic and oxidative systems was analyzed at rest, during the HIIE sessions and for 20 min post. Performance variables (time to exhaustion, number of efforts) and oxygen consumption were also analyzed.ResultsMIPS significantly increased the number of efforts performed (MIPS: 41 ± 10 vs Placebo: 36 ± 12, p = 0.0220) and time to exhaustion (MIPS: 20.1 ± 6 min vs Placebo: 17 ± 5 min, p = 0.0226). There was no difference between supplements for both T90% V̇O2max (p = 0.9705) and EPOC (p = 0.4930). Consuming MIPS significantly increased the absolute oxidative energy system contribution by 23.8% (p = 0.0163) and the absolute ATP-CP contribution by 28.4% (p = 0.0055) compared to placebo. There was only a non-significant tendency for a higher glycolytic system contribution after MIPS ingestion (p = 0.0683).ConclusionAcute MIPS ingestion appears effective at increasing both aerobic and anaerobic alactic energy contribution and time to exhaustion during a HIIE protocol.

Beta alanine supplementation effects on metabolic contribution and swimming performance

BackgroundInvestigations of β-alanine supplementation shows effects on metabolic (aerobic and anaerobic) participation and performance on swimming by a possible blood acidosis buffering. Considering this background, the objective of the present study was to analyze the effects of β-alanine supplementation on metabolic contribution and performance during 400-m swim.MethodsThirteen competitive swimmers underwent a 6-week, double-blind placebo-controlled study, ingesting 4.8 g.day− 1 of β-alanine or placebo. Before and after the supplementation period, the total anaerobic contribution (TAn) and 30-s all-out tethered swimming effort (30TS) were assessed. Anaerobic alactic (AnAl) and lactic energy (AnLa) was assumed as the fast component of excess post-exercise oxygen consumption and net blood lactate accumulation during exercise (∆[La−]), respectively. Aerobic contribution (Aer) was determined by the difference between total energy demand and TAn. In addition to conventional statistical analysis (Repeated measures ANOVA; p > 0.05), a Bayesian repeated measures ANOVA was used to evidence the effect probability (BFincl).ResultsNo differences and effects were found between groups, indicating no supplementation effects. Repeated measures ANOVA, with confirmation of effect, was indicate reduce in ∆Lactate (p: 0.001; BFincl: 25.02); absolute AnLa (p: 0.002; BFincl: 12.61), fatigue index (p > 0.001; BFincl: 63.25) and total anaerobic participation (p: 0.008; BFincl: 4.89).ConclusionsThus, the results demonstrated that all changes presented were evidenced as a result of exposure to the training period and β-alanine supplementation doesn’t affect metabolic contribution and performance during 400-m freestyle.

Relative Aerobic and Anaerobic Energy Contributions during Short-Duration Exercise Remain Unchanged over A Wide Range of Exercise Intensities

Relative Aerobic and Anaerobic Energy Contributions during Short-Duration Exercise Remain Unchanged over A Wide Range of Exercise Intensities

The 400-m Front Crawl Test: Energetic and 3D Kinematical Analyses.

The aim of the study was to verify the relative contributions of energetic and kinematic parameters to the performance in 400-m front crawl test. Fourteen middle-distance swimmers participated in the study. Oxygen consumption was measured directly and blood samples were collected to assay lactate concentration. Both oxygen consumption and lactate concentration were used to calculate the: (i) overall energy expenditure, (ii) anaerobic (alactic and lactic) and (iii) aerobic contributions. The mean centre of mass speed and intracycle velocity variation were determined through three-dimensional kinematic analysis. Mean completion time was 315.64±26.91s. Energetic contributions were as follows: 6.1±0.28% from alactic anaerobic metabolism, 5.9±0.63% from anaerobic lactic and 87.8±0.88% from aerobic. Mean intracycle velocity variation was 0.14±0.03. The results indicated that performance of 400-m test relies predominantly on aerobic power. Parameters such as lactate, mean speed, anaerobic lactic and alactic (kW) correlated with performance of 400-m test (p

Relative aerobic and anaerobic energy contribution in race fit endurance and Thoroughbred racehorses during strenuous exercise

The objective was to compare fit Arabian endurance and Thoroughbred racehorses’ responses to a maximal intensity standardised incremental treadmill test (MaxSIT) with respect to: (1) their relative aerobic contributions during maximal exercise; and (2) selected physiological parameters related to performance. Six high-level endurance Arabians and six race-ready Thoroughbreds performed a MaxSIT starting at 8 m/s and increasing by 1 m/s increments 60 s until maximum oxygen consumption (V̇O2max) was reached. Heart rate (HR), blood lactate concentration (BLac), haematocrit (Hct), minute ventilation (V̇E) and oxygen consumption (V̇O2) were measured. V̇O2max, the speeds at which the HR were 200 and 160 bpm, respectively (V200, V160), the speed at which the BLac reached 4 mmol/l (VLa4) and lactate at HR200(BLa200) were calculated. The relative aerobic energy input was determined using ΔBLacPeak-Restingincrease as previously described. Data were expressed as median with interquartile range and analysed with a Wilcoxon rank sum test (P&lt;0.05). Endurance horses had greater V̇O2max(202.5 ml/(kg.min) (190.3-211) vs 152.7 ml/(kg.min) (140.5-158.3);P&lt;0.001) and had a greater aerobic energy contribution to total exercise effort (89.9% (87.0-96) vs 82.8% (81.1-84.1);P=0.009) than Thoroughbreds. Endurance horses reached HR&gt;200 bpm on the treadmill, but had a lower HRmax(210 bpm (205-217) vs 226 bpm (219-228);P=0.008), BLa200(3.8 mmol/l (2.7-5.5) vs 4.8 mmol/l (3.6-5.2);P&lt;0.001) and Hctmax(56.4% (54.9-57.5) vs 61.5% (59-64);P=0.002). Endurance horses median VLa4 was 11.6 m/s (11.0-13.0); V200=11.9 m/s (10.9-12.3) and V160=8.5 m/s (7.2-8.6). Because of the HR and speed characteristics of modern endurance races, we proposed BLa200as a new calculated parameter with which to assess endurance horses. Trained endurance horses accumulate less lactate, have a greater V̇O2maxand relative aerobic contribution to their energy requirements at maximal intensity exercise despite a lower blood haematocrit.