Anaerobic Work Capacity Research Articles

Acute alcohol ingestion decreases the work done above the end-test power during a 3-min all-out cycling exercise.

Alcohol ingestion influences metabolism during a subsequent exercise session, as evidenced by increased blood lactate concentration during fixed-intensity exercise. Therefore, augmented blood concentrations of alcohol may interfere with the anaerobic metabolism during high-intensity, short-duration exercise bout, thereby leading to impaired athletic performance. This study investigated whether the acute ingestion of alcohol as ethanol modulates performance parameters derived from the power-duration relationship in a 3-min all-out cycling test that allows for identifying the power output related to heavy and severe exercise intensities. Twenty-four recreationally active cyclists (16 men and 8 women) ingested a beverage containing either 0.4g ethanol.kg-1 body mass (EtOH) or a placebo (PLA) solution. Thirty minutes following ingestion, they completed a 3-min all-out test to measure power output and determine the end-test power (EP) and the work done above EP (WEP). Alcohol ingestion decreased WEP by 16% (EtOH: 5.6 ± 2.5kJ vs. PLA: 6.7 ± 2.4kJ; P = .003) but did not change EP (EtOH: 211 ± 44W vs. PLA: 212 ± 44W; P = .671). The alcohol-mediated effect in WEP was not influenced when controlling for participants' sex or accuracy in identifying the beverage ingested. Our data indicate that alcohol ingestion impaired the anaerobic work capacity, as evidenced by the reduction in WEP during the 3-min all-out test. Moreover, the ability to exercise at an intensity above the heavy domain may be decreased after ingestion of a moderate alcohol dose.

THE INFLUENCE OF BIOFEEDBACK ON ANAEROBIC WORKING CAPACITY IN JUMP TEST IN THE SCHOOLCHILDREN AGED 11-12

THE INFLUENCE OF BIOFEEDBACK ON ANAEROBIC WORKING CAPACITY IN JUMP TEST IN THE SCHOOLCHILDREN AGED 11-12

APRIMORAMENTO DA COORDENAÇÃo FÍSICA DOS NADADORES BASEADO NO TREINAMENTO DE RESISTÊNCIA ANAERÓBICA

ABSTRACT Introduction: Anaerobic exercise is a critical factor in swimming training. Coaches who monitor an athlete’s anaerobic capacity can use this tool to improve competitive performance. Objective: Analyze the effect of the anaerobic function test on swimmers’ training. Methods: We examined the anaerobic exercise capacity of swimmers the relationship between human body composition and anaerobic work capacity. For this purpose, 14 swimmers were selected by random sampling. Individual anaerobic threshold, serum testosterone and serum cortisol of the athletes at different periods were measured. Results: Individual anaerobic thresholds were significantly lower in male and female athletes after training. The difference was statistically significant (P<0.05). The plasma testosterone/cortisol content of female swimmers after six weeks of anaerobic endurance training was significantly lower than the pre-training mean (P<0.05). After six weeks of anaerobic endurance training, the plasma testosterone/cortisol content of the male swimmers was lower than that of the standard group (P<0.05). Conclusion: The swimmers’ bodies were impacted after anaerobic endurance training. The importance of attention by the coach to consider the differences between male and female athletes when conducting dedicated anaerobic threshold training is emphasized. Level of evidence II; Therapeutic studies-investigating treatment outcomes .

EFFECTS OF HIGH-INTENSITY INTERVAL TRAINING ON THE ANAEROBIC CAPACITY OF WRESTLERS

ABSTRACT Introduction Since the Wingate anaerobic experiment was proposed in the 1970s, it has come to be used as an important detection method to evaluate athletes’ high-power sport capacity, the effect of training, and the training method. Therefore, it is often used to measure and evaluate the anaerobic work capacity of the human body. Objective Analyze the effects of high-intensity interval training on the anaerobic capacity of male wrestlers. Methods Professional wrestlers from a sports college were selected, as well as 30 college students majoring in physical education at a sports college, to compare the anaerobic power test. Results When evaluated by the Wingate anaerobic experiment, the value level of anaerobic power of training effects is best reflected in the first 10 s of the wrestling anaerobic experiment. The 30 s Wingate mainly reflects the effect of wrestling training on human anaerobic power, but the evaluation of anaerobic capacity from this period was not evidenced. Conclusion The Wingate anaerobic experiment is an important method for evaluating the level of wrestling training and can be used as a basis for evaluating the effect of training and the level of wrestling. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

Field-Derived Maximal Power Output in Cycling: An Accurate Indicator of Maximal Performance Capacity?

To determine the validity of field-derived mean maximum power (MMP) values for monitoring maximal cycling endurance performance. Twenty-seven male professional cyclists performed 3 timed trials (TTs) of 1-, 5-, and 20-minute duration that were used as the gold standard reference. Field-based power output data (3336 files; 124 [25] per cyclist) were registered during the preparatory (60d pre-TT, including training data only) and specific period of the season (60d post-TT, including both training and competitions). Comparisons were made between TT performance (mean power output) and MMP values obtained for efforts of the same duration as TT (MMP of 1-, 5-, and 20-min duration). The authors also compared TT- and MMP-derived values of critical power (CP) and anaerobic work capacity. A large correlation (P < .001, r > .65) was found between MMP and TT performance regardless of the effort duration or season period. However, considerable differences (P < .05, standard error of measurement [SEM] > 5%) were found between MMP and TT values for all effort durations in the preparatory period, as well as for the derived CP and anaerobic work capacity. Significant differences were also found between MMP and TT of 1 minute in the specific period, as well as for anaerobic work capacity, yet with no differences for MMP of 5- and 20-minute duration or the derived CP (P > .05, SEM < 5%). MMP values (for efforts ≥5min) and the associated CP obtained from both training sessions and competitions can be considered overall accurate indicators of the cyclist's maximal capabilities, but specific tests might be necessary for shorter efforts or when considering training sessions only.

A simulation study to compare physiological responses to hypoxia and exercise between anaemic subjects and healthy controls

Objectives: Military flying is a complex task and requires high level of physical fitness of aviators. Various aviation stressors such as acceleratory force, hypoxia, cold weather conditions and decompression sickness place enormous stress on human physiological systems of the aviators. Individuals with Hb &lt;13 g/dL (males) are being placed in the lower medical category which makes them unfit to fly. The present study was undertaken to assess the implication of low haemoglobin (Hb) on exercise capacity and hypoxia tolerance. Materials and Methods: Twenty-five individuals with anaemia and 15 healthy controls participated in the study. The participants were subjected to normobaric hypoxia (NH) equivalent to an altitude of 15,000 feet. Different physiological parameters such as heart rate (HR), systolic and diastolic blood pressure (SBP and DBP), respiratory rate (fR) and arterial oxygen saturation (SpO2) were measured during NH. Participants also performed maximal aerobic capacity (VO2 max) and maximal anaerobic capacity test in bicycle ergometer. Results: HR, SBP, DBP and fR in anaemic subjects were higher than healthy controls during NH, whereas SpO2 in anaemic subjects was lower as compared to healthy controls. Anaemic individuals had a lower VO2 max than their healthy counterparts. Critical power and anaerobic work capacity were lower in anaemic subjects than healthy controls. Conclusion: There is a deterioration in exercise capacity and hypoxia tolerance in individuals with low Hb levels. Adequate precaution should be exercised for permitting military aviators to fly with low Hb level.

Anaerobic work capacity in cycling: the effect of computational method

PurposeTo compare the anaerobic work capacity (AnWC, i.e., attributable anaerobic mechanical work) assessed using four different approaches/models applied to time-trial (TT) cycle-ergometry exercise.MethodsFifteen male cyclists completed a 7 × 4-min submaximal protocol and a 3-min all-out TT (TTAO). Linear relationships between power output (PO) and submaximal metabolic rate were constructed to estimate TT-specific gross efficiency (GE) and AnWC, using either a measured resting metabolic rate as a Y-intercept (7 + YLIN) or no measured Y-intercept (7-YLIN). In addition, GE of the last submaximal bout (GELAST) was used to estimate AnWC, and critical power (CP) from TTAO (CP3´AO) was used to estimate mechanical work above CP (W’, i.e., “AnWC”).ResultsAverage PO during TTAO was 5.43 ± 0.30 and CP was 4.48 ± 0.23 W∙kg−1. The TT-associated GE values were ~ 22.0% for both 7 + YLIN and 7-YLIN and ~ 21.1% for GELAST (both P < 0.001). The AnWC were 269 ± 60, 272 ± 55, 299 ± 61, and 196 ± 52 J∙kg−1 for the 7 + YLIN, 7-YLIN, GELAST, and CP3´AO models, respectively (7 + YLIN and 7-YLIN versus GELAST, both P < 0.001; 7 + YLIN, 7-YLIN, and GELAST versus CP3´AO, all P < 0.01). For the three pair-wise comparisons between 7 + YLIN, 7-YLIN, and GELAST, typical errors in AnWC values ranged from 7 to 11 J∙kg−1, whereas 7 + YLIN, 7-YLIN, and GELAST versus CP3´AO revealed typical errors of 55–59 J∙kg−1.ConclusionThese findings demonstrate a substantial disagreement in AnWC between CP3´AO and the other models. The 7 + YLIN and 7-YLIN generated 10% lower AnWC values than the GELAST model, whereas 7 + YLIN and 7-YLIN generated similar values of AnWC.

Relationship between anaerobic work capacity and critical oxygenation in athletes

Objective: Anaerobic work capacity (AWC) is understood as the maximum power that the athlete can withstand over time, conditioned by high intensity effort and it is important to interpret it for the performance improvement. In addition, the muscle oxygen saturation (SmO2) provides information on muscle metabolism and hemodynamics. Likewise, critical oxygenation (CO) is the highest metabolic rate that results in a fully oxidative energy supply that reaches a stable state at the substrate level. The main problem is that SmO2 generally offers a traditional laboratory interpretation without application in field tests, Therefore, the purpose of this study is to provide the use of CO as an indicator of AWC performance in high intensity exercise. &#x0D; Methods: Twenty-two male rugby players participated. Peak torques during an isokinetic fatigue test and muscle oxygen consumption (mVO2) and SmO2 in the vastus lateralis were measured. A correlation and multiple regression analysis were applied to find an explanatory prediction model of the AWC. &#x0D; Results: A greater SmO2 amplitude and CO would mean less anaerobic work (r = -0.58 and r=-0.63) and less force production. In addition, CO along with weight (kg) can explain the AWC by 64% during high intensity exercise. &#x0D; Conclusion: The measurement of critical oxygenation is associated with the AWC, so should be considered a performance factor. These parameters could be included in NIRS sensors to evaluate muscle metabolism.

Associations among sleep, hematologic profile, and aerobic and anerobic capacity of young swimmers: A complex network approach.

Although the link between sleep and hematological parameters is well-described, it is unclear how this integration affects the swimmer’s performance. The parameters derived from the non-invasive critical velocity protocol have been extensively used to evaluate these athletes, especially the aerobic capacity (critical velocity—CV) and the anaerobic work capacity (AWC). Thus, this study applied the complex network model to verify the influence of sleep and hematological variables on the CV and AWC of young swimmers. Thirty-eight swimmers (male, n = 20; female, n = 18) completed five experimental evaluations. Initially, the athletes attended the laboratory facilities for venous blood collection, anthropometric measurements, and application of sleep questionnaires. Over the 4 subsequent days, athletes performed randomized maximal efforts on distances of 100, 200, 400, and 800-m. The aerobic and anerobic parameters were determined by linear function between distance vs. time, where CV relates to the slope of regression and AWC to y-intercept. Weighted but untargeted networks were generated based on significant (p < 0.05) correlations among variables regardless of the correlation coefficient. Betweenness and eigenvector metrics were used to highlight the more important nodes inside the complex network. Regardless of the centrality metric, basophils and red blood cells appeared as influential nodes in the networks with AWC or CV as targets. The role of other hematologic components was also revealed in these metrics, along with sleep total time. Overall, these results trigger new discussion on the influence of sleep and hematologic profile on the swimmer’s performance, and the relationships presented by this targeted complex network can be an important tool throughout the athlete’s development.

Beta-alanine supplementation and anaerobic performance in highly trained judo athletes

Introduction. Previous studies have shown that several weeks of beta-alanine (BA) supplementation increases anaerobic work capacity and decreases muscular fatigue, but limited research was conducted on elite martial arts athletes. Therefore, the purpose of this study was to investigate the effect of chronic BA supplementation on high-intensity intermittent upper and lower-body performance in highly-trained judo athletes. Material and Methods: Sixteen elite judo athletes (21.8 ± 2.5 years old) were randomly assigned to receive either BA (4 g/d over the first 2 weeks and 6 g/d in the last 2 weeks) or placebo for 4 weeks. Before and after BA supplementation, the athletes completed two double 30-s upper and lower limb Wingate tests, separated by 3 min. Blood samples were collected for lactate and di-carbonate concentration at baseline and post-exercise. Results: BA supplementation improved Lower and Upper Limb Total Work (p &lt; 0.001) and Upper Limb Mean Power (p &lt; 0.001) during Wingate Test. However, there were no significant differences in Lower Limb Mean Power in the BA group and in any obtained results in the placebo group. Additionally, a significant increase in the postworkout lactate and di-carbonate concentration (p &lt; 0.001) was observed. Conclusions: Chronic supplementation of BA effectively enhances high-intensity intermittent upper and lower-body performance in highly-trained judo athletes.

Effect of Fatiguing Wheelchair Propulsion and Weight Relief Lifts on Subacromial Space in Wheelchair Users.

ObjectiveThis study aimed to identify targets of intervention for reducing shoulder pain in wheelchair users with spinal cord injury (SCI) by (1) examining changes in subacromial space [acromiohumeral distance (AHD) and occupation ratio (OccRatio)] with fatiguing wheelchair propulsion, and different loading conditions [unloaded position vs. weight relief lifts (WRL)]; (2) associating these changes with wheelchair user capacity, as well as (3) identifying subject characteristics associated with subacromial space, such as sex, lesion level, time since injury, body mass index and impaired shoulder range of motion.MethodsFifty manual wheelchair users with SCI [11 females, age = 50.5 (9.7) years, time since injury = 26.2 (11.4) years] participated in this quasi-experimental one-group pretest-posttest study. Ultrasound images were used to define AHD during an unloaded position, and during personal and instructed WRL before and after fatiguing wheelchair propulsion. Furthermore, supraspinatus and biceps thickness defined from ultrasound images were used to calculate OccRatios. Wheelchair user capacity was quantified as functional strength (maximum resultant force reached during maximum isometric forward push) and anaerobic work capacity (highest power output reached during 15-m sprint test). Multilevel mixed-effects linear regression analyses controlling for between subject variability and covariables were performed to address the research questions.ResultsAHD was significantly smaller during personal WRL (p < 0.001) and instructed WRL (p = 0.009, AHD both 11.5 mm) compared to the unloaded position (11.9 mm). A higher wheelchair user capacity (higher anaerobic work capacity) reduced the impact of WRL on AHD decrease. The fatiguing wheelchair propulsion had no effect on AHD (p = 0.570) and on OccRatio of supraspinatus (p = 0.404) and biceps (p = 0.448). Subject characteristics related to a larger subacromial space were lower lesion level, shorter time since injury, impaired external rotation, a lower body mass index and a higher anaerobic work capacity.ConclusionThis study showed a significant reduction in AHD during WRL with no effect of fatiguing wheelchair propulsion on the subacromial space in wheelchair users with SCI. A higher anaerobic work capacity was beneficial in stabilizing the shoulder during WRL. Our findings may assist clinicians in designing a shoulder injury prevention program.

Caffeine intake improves muscular endurance and induces depletion of anaerobic work capacity in the bench press

Aim: To investigate the effects of caffeine (CAF) ingestion on anaerobic work capacity (AWC) and muscular endurance in the bench press exercise at predictive intensities equivalent to 20, 25, and 30% of 1RM. Methods: Thirteen males (age: 23 ± 3 years; body mass 83.5 ± 4.9 kg; height 172.8 ± 5.0 cm and 1RM 82 ± 24 kg) had their 1RM test evaluated in the bench press exercise and the time until failure was performed at intensities equivalent to 20%, 25%, and 30% of 1RM to CAF (350mg) or placebo (PLA, cellulose). AWC was measured from the linear equation: “Force = Critical Force + (AWC x 1/timeout)”. Results: CAF enhanced the time until failure at 20% of 1RM (PLA = 202.6 ± 29.1s; CAF = 243.2 ± 20.6s), but there was no ergogenic effect at 25% (PLA = 188.8 ± 23.5 s; CAF = 195.6 ± 27.1 s), and 30% (PLA = 147.4 ± 15.8 s; CAF = 145.4 ± 14.8 s). AWC in CAF was lower than PLA (PLA = 6378.0 ± 1214.9 J; CAF = 3246.4 ± 1389.7 J; p = 0.03; Effect size = 0.88). Critical Force (N) was not different between treatments PLA 29.97 ± 11.54% of 1RM and CAF 3.74 ± 3.69% of 1 RM (p=0.47; Effect size= 0.28). Conclusion: Acute CAF intake (350mg) reduces the AWC and increases the time until failure at 20% of 1 RM, but not Critical Force and muscular endurance at 25% and 30% of 1 RM in the bench press.

Research of Cycling Race Strategy Based on Segment Optimization Technique

This paper examines race strategies in cycling to help athletes win. The three-parameter CP model, which is regarded to critical power CP, anaerobic work capacity AWC and the maximum duration T, and a total energy consumption model are establishment in this paper. We present a segmented optimum technique to investigate riders’ energy distribution, whose target is to obtain relative optimality in each divided tiny time period. To build a total energy consumption model, the player's functional threshold power FTP, available anaerobic work W', and fatigue effect α are all taken into account throughout each time period tk. Then we investigate two typical stages of courses: straight sections and slopes. The model is then applied to real track. The results reveal that the theoretical final time has little difference when compared to the champion's time.

Effects of Eight Interval Training Sessions in Hypoxia on Anaerobic, Aerobic, and High Intensity Work Capacity in Endurance Cyclists.

Aim: This study aimed to determine if eight sessions of supramaximal but steady-state, set duration interval training in hypoxia enhanced measured anaerobic capacity and work performed during high intensity exercise. High Alt Med Biol. 21:370-377, 2020. Materials and Methods: Eighteen cyclists (V̇O2peak: 57 ± 7 ml·kg-1·min-1) were pair-matched for anaerobic capacity determined by maximal accumulated oxygen deficit (MAOD) and allocated to a 4-week interval training in hypoxia (IHT; FiO2 = 14.7% ± 0.5%, n = 9) or interval training in normoxia (NORM; FiO2 = 20.6% ± 0.3%, n = 9). Cyclists completed twice weekly interval training (8 × 1 minutes: ∼120% V̇O2peak, 5 minutes recovery: ∼50% V̇O2peak) in addition to their habitual training. Before and after the intervention, a constant work rate supramaximal time to fatigue and a graded exercise test were used to determine changes in anaerobic capacity/supramaximal work performed and aerobic capacity/peak aerobic power output, respectively. Results: No interaction or main effects were observed. Using indirect calorimetry, anaerobic capacity was not significantly different in either group pre- to postintervention using MAOD (IHT: 4% ± 15%; NORM: -5% ± 12%) or gross efficiency methods (IHT: 7% ± 14%; NORM: -2% ± 9%), and VO2peak was unchanged (IHT: 1% ± 6%; NORM: 1% ± 4%). However, within-group analysis shows that supramaximal work performed improved with IHT (14% ± 13%; p = 0.02; d = 0.42) but not NORM (1% ± 22%), and peak aerobic power output increased with IHT (5% ± 7%; p = 0.04; d = 0.32) but not NORM (2% ± 4%). Conclusion: Steady-state, set duration supramaximal interval training in hypoxia appears to provide a small beneficial effect on work capacity during supramaximal and high intensity exercise.

Validity Of A Field-based Critical Velocity Test On Predicting 5,000 M Running Performance

Measuring and modeling known adaptations to endurance training can be achieved through a variety of physiological parameters. A unique and emerging performance parameter receiving attention is the notion of critical velocity (CV). This concept allows an athlete’s performance to be mathematically modeled based on the relationship that exists between distance and time. PURPOSE: To assess the validity of a field-based CV test on predicting 5,000 m running performance. METHODS: Five runners (VO2peak 60.14 ± 4.96 ml•kg-1•min-1) completed a graded exercise test to determine VO2peak, a CV test to predict performance, and a 5,000 m time-trial. The CV assessment protocol included time-trials of 3,600 m, 2,400 m, and 1,200 m at maximal exertion on a standard 200 m indoor track. Running performance was predicted using the distance-time model where CV was given by the slope and the anaerobic work capacity (D’) was given by the intercept from linear regression analysis of distance covered against time for each of the three time-trials. Statistical significance was determined a priori at p < 0.05. RESULTS: Predicted 5,000 m performance (18.28 ± 4.38 min) and actual 5,000 m performance (18.17 ± 4.07 min) were not significantly different, t(4) = 0.58, p = 0.594, d = 0.26. The mean difference in performance was 0.11 ± 0.42 min [95% LoA, -0.71 min, 0.93 min]. CV (4.59 ± 0.88 m•s-1) was significantly slower than actual 5,000 m velocity (4.73 ± 0.82 m•s-1), t(4) = -3.081, p < 0.05, d = -1.37. The mean difference in velocity was -0.14 m•s-1 ± 0.10 m•s-1 [95% LoA, -0.34 m•s-1, 0.06 m•s-1]. CONCLUSION: The linear distance-time model can be used to predict 5,000 m running performance. This field-based approach allows performance predictions to be made in a relatively short period of time without the need for access to expensive laboratory equipment.

Dynamic post-activation potentiation protocol improves rowing performance in experienced female rowers

ABSTRACT Post-activation potentiation likely acutely improves power-based performance; however, few studies have demonstrated improved endurance performance. Forty collegiate female rowers performed isometric potentiating (ISO), dynamic potentiating (DYN) and control (CON) warm-up protocols on a rowing ergometer, followed by a three-minute all-out test to evaluate their total distance, peak power, mean power, critical power, anaerobic working capacity (W’) and stroke rate. Fifteen-second splits were also analysed. ISO consisted of 5 × 5-second static muscle actions with the ergometer handle rendered immovable with a nylon strap, while DYN consisted of 2 × 10-second all-out rowing bouts, separated by a 2-minute rest interval. The participants were divided into high and low experience groups by median experience level (3.75 years) for statistical analysis. Significant differences (DYN > CON; p < 0.05) were found for distance (+5.6 m), mean power (+5.9 W) and W’ (+1561.6 J) for more experienced rowers (n = 19) and no differences for less experienced rowers (n = 18). Mean power in DYN was significantly greater than CON and ISO in the 15–30, 30–45, 45–60 and 60–75 second intervals independent of experience level. These results suggest that DYN may benefit experienced female rowers and that these strategies might benefit a greater power output over shorter distances regardless of experience.

Chronic metformin intake improves anaerobic but not aerobic capacity in healthy rats.

The effect of chronic metformin intake on aerobic and anaerobic capacity was examined in healthy rats. Twenty rats completed 10 days of metformin (MET) ingestion (250 mg). After this period, the animals performed four high-intensity bouts until exhaustion at 9%, 11%, 13%, and 15% of body mass (BM) in swimming, separated by 24 h, with prior metformin (250 mg) or placebo (PL). The critical load (CL) and anaerobic work capacity (AWC - W') were calculated and considered aerobic and anaerobic capacity, respectively. There was no difference in CL between the MET and PL groups (p > 0.05). The AWC - W' was higher in the MET group than in the PL group (p = 0.004). Time until exhaustion (seconds) at all bouts were higher (p < 0.004) in the MET group (9% of BM = 434.5 ± 267.3, 11% of BM = 269.6 ± 214.2, 13% of BM = 174.0 ± 40.9, 15% of BM = 146.6 ± 15.9) compared to the PL group (9% of BM = 96.4 ± 22.3, 11% of BM = 65.5 ± 13.4, 13% of BM = 51.1 ± 5.5, 15% of BM = 40.8 ± 7.5). Glucose concentration was higher at 90 and 120 min than at 0 and 30 min for the MET group (intragroup) during the oral glucose test tolerance; there was no difference between the MET and PL groups for area under curve. MET ingestion enhances AWC - W' and times to exhaustion but not aerobic capacity.

Power profiling in elite U23 riders during a competitive season

Power profiling in elite U23 riders during a competitive season Peter Leo 1 , Inigo Mujika 2 , Verena Menz and Justin Lawley 3 1 Cycling Team Tirol, Innsbruck Austria 2 University of the Basque Country 3 University of Innsbruck, Sports Science Department Background: Changes in the power profile of elite U23 cyclists throughout a competitive season could provide valuable information about racing demands and the training process. A rider’s power-duration relationship shows a dynamic behaviour affected by training and racing, and repeated computation is required to gain accurate insights into a rider’s performance capabilities. Assessing the power-duration relationship by means of different performance tests in the field is one common way to proceed. However, such tests require regular attempts as well as a motivated and rested athlete, which could be difficult during a competitive season. Therefore, the aim of this study was to investigate changes in the power-duration relationship based on peak power output values obtained during racing. Methods: Fourteen highly trained elite U23 cyclists (N=14; mean ± SD age 20.6 ± 1.1 years; body mass 67.7 ± 6.0 kg; height 180.7 ± 5.6 cm; maximum oxygen uptake 73.9 ± 2.0 mL·kg-1 min-1·; maximal aerobic power 443 ± 27 W) completed 3 maximal efforts on their road bike in the pre-competitive period. The efforts lasted 12, 5 and 2 min on a climb of 5-6% gradient, interspersed by a 30-min recovery period after each trial. In a further step 12, 5 and 2 min power outputs were used to calculate critical power and anaerobic work capacity. During the competitive season peak power outputs during efforts lasting 12, 5 and 2 min were used to track changes in the power-duration relationship over three consecutive periods, for the early (February – April), mid (May – July) and late (August – October) season. A repeated-measure ANOVA was used to compare the peak power outputs across the three periods. Results: Mean power output during the 12, 5 and 2 min maximal effort trials were 379 ± 23, 420 ± 7 and 505 ± 33 W, respectively, resulting in a critical power of 352 ± 24 W (see Graph 1).   Graph 1: Mean power outputs of the pre - season Critical Power Test The 2 min peak power outputs over the three consecutive periods were 484 ± 54, 515 ± 35 and 518 ± 40 W, with significant differences between the first and third periods (p = 0.009). The 5 min peak power outputs were 415 ± 26 W, 441 ± 25 W and 445 ± 24 W, with significant changes between the first and second (p = 0.012) as well as first and third (p = 0.002) periods. Peak power outputs for 12 min were 373 ± 32 W, 397 ± 26 W and 405 ± 24 W, with significant differences between the first and second (p = 0.001) as well as the first and third periods (p = 0.001). Critical power values (see Graph 2) during the three consecutive periods were 342 ± 9 W, 360 ± 6 W and 366 ± 6 W, with significant changes between the first and third periods (p = 0.017).  Graph 2: Variations in Critical power before and during the season Discussion: These findings reveal that variations in peak power outputs during a competitive season have a significant influence on the power-duration relationship. Relatively small changes in peak power outputs could nonetheless be of practical relevance . Indeed, mean improvements of 8.6%, 7.2% and 7.0% in 12, 5 and 2 min peak power outputs from the first to the third period could be quite beneficial for a rider’s and a team’s competition outcomes. In addition, using racing power output data to determine the power-duration relationship as well as parameter estimates of critical power might be a practical means of assessing a cyclist’s fitness. Keywords : cycling, power-duration relationship, critical power

Examining Work-to-Rest Ratios to Optimize Upper Body Sprint Interval Training

PURPOSE: The primary purpose of this study was evaluate the effectiveness of upper body sprint interval training (SIT) protocols with varying work-to-rest ratios on both aerobic and anaerobic performance. The secondary purpose was to investigate the changes in metabolic and neuromuscular fatigue thresholds from two weeks of SIT in recreationally active men. METHODS: Forty-two recreationally trained men were randomized into one of three training groups [10s work bouts with two minutes of rest (10:2) or four minutes of rest (10:4), or 30s work bouts with four minutes of rest (30:4)] or a control group (CON). Participants underwent six training sessions over two weeks with four to six ‘all-out’ sprints. During pre- and post-intervention visits, participants underwent a graded exercise test to determine maximal oxygen consumption (V̇ O2peak) and peak power output (PPO), four constant-work rate trials to determine critical power (CP), anaerobic working capacity (W’), and electromyographic fatigue threshold (EMGFT), and an upper body Wingate test to determine peak power (PP), mean power (MP), and total work (TW). An analysis of covariance was performed on all testing measurements collected at post with the associated pre-values used as covariates. RESULTS: There were significant between group differences in post-test absolute V̇ O2peak, with an adjusted pre-test mean of 2.44L·min-1, and PPO, with an adjusted pre-test mean of 130.9W. Absolute V̇ O2peak was greater in 30:4 (2.36±0.26L·min-1, p = .007) and 10:2 (2.53±0.38L·min-1, p = .036) than CON (2.17±0.34L·min-1), and PPO was greater in 30:4 than CON (136±14 vs. 127±22W, p = .007, respectively). No differences were observed between groups in CP (p = .530), W’ (p = .900), EMGFT (p = .692), PP (p = .692), MP (p = .290), or TW (p = .291). CONCLUSION: SIT protocols with larger work-to-rest ratios appears to have enhanced V̇ O2peak in the upper body over a short-term two-week intervention.

Impact of dietary nitrate supplementation on the speed/duration relationship in mice with sickle cell anemia

Sickle cell disease (SCD) compromises nitric oxide (NO) bioavailability and results in a plethora of cardiopulmonary and skeletal muscle complications causing severe exercise intolerance. It is now widely recognized that dietary nitrate can be reduced to nitrite and, subsequently, NO and impact hemodynamic and metabolic control during exercise. Therefore, the purpose of this investigation was to measure the impact of nitrate supplementation on exercise capacity as measured by the running speed/ exercise duration relationship (critical speed, CS) and the anaerobic work capacity (W′, the finite work capacity available above CS) in mice with SCD. We tested the hypothesis that dietary nitrate supplementation via beetroot juice (BR) would attenuate the exercise intolerance observed in mice with SCD. Ten wild‐type (WT) and 18 Berkley sickle‐cell mice (BERK) received either water (WT: n=10, BERK: n=10) or nitrate‐rich BR (BERK+BR: n=8, nitrate dose 1 mmol/kg/day) for five days). Following the supplementation period, all mice performed 4 constant‐speed treadmill tests that resulted in fatigue within 1.5 to 20 min. Time to fatigue vs. treadmill speed were fit to a hyperbolic model to determine CS. Speed and time to exhaustion for WT, BERK, and BERK+BR conformed to a hyperbolic relationship (WT: r2 = 0.93 ± 0.02, BERK: r2 = 0.97 ± 0.01, BERK+BR: r2= 0.97 ± 0.03, p&gt;0.05). CS was significantly lower in BERK when compared to WT and BERK+BR with no significant difference between WT and BERK+BR (WT: 33.1 ± 1.5, BERK: 24.7 ± 0.7, BERK+BR: 31.9 ± 1.4 m/min, p&lt;0.05). Additionally, the W′ was significantly higher in BERK relative to WT and BERK+BR (WT: 1456.2 ± 237.2, BERK: 2639.2 ± 106.8, BERK+BR: 1134.7 ± 156.7, P&lt;0.05). To summarize, exercise tolerance, as measured via CS, was significantly lower in BERK mice relative to WT. However, BERK mice that had received a 5‐day dietary nitrate intervention exhibited no difference in exercise tolerance when compared to WT. In addition, the W′ was significantly higher in BERK mice relative to WT, but this difference was not observed in BERK+BR. The CS threshold is a well‐described fundamental feature of exercise energetics that represents the highest sustainable rate of aerobic metabolism and remains valid across species. Considering the lower CS in BERK mice and the ability of BR to restore CS in BERK mice, these results provide compelling support for the use of a dietary nitrate intervention to improve functionality in the SCD patient population.Support or Funding InformationFunded by NIH (R01HL125642) to DCI and Colorado Nutrition and Obesity Research Center (P30DK048520) award to SKF.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.