Repeated Sprint Cycling Performance Research Articles

The effect of ischemic preconditioning on repeated sprint cycling performance: a randomized crossover study.

Ischemic preconditioning (IPC) has been suggested to improve exercise performance by 1-8%. Prior research concerning its impact on short-duration exercises, such as sprints, has been limited and yielded conflicting results. The aim of this study, which included a non-occlusion-based placebo control, was to determine whether IPC improves repeated sprint performance in a manner that accounted for psychophysiological effects. Twenty-two healthy males participated in this study, which employed a randomized crossover design. Following the 10-min baseline period, participants received intervention under four different conditions: 1) no-intervention control (CON); 2) non-occlusion-based placebo control (SHAM); 3) remote IPC (RIPC); and 4) local IPC (LIPC). Participants then performed a standardized repeated sprint cycling (5×10s maximal cycling sprint, separated by a 40-s rest in each set). Repeated sprint performance, as indexed by average power output, peak power output, and total work, the improvement was observed in the RIPC and LIPC during the initial phase (set 1-3) when compared with CON (P<0.05). SHAM condition also showed an increase in peak power output in the set 1 (CON 9.97±1.05 vs. SHAM 10.30±1.13 w/kg, P<0.05), which may represent a psychophysiological component in the IPC-induced improvement. Higher lactate concertation was found in the SHAM and LIPC groups, than in the CON group, 5 minutes after the exercise (CON 15.72±0.68 vs. SHAM 16.82±0.41 vs. LIPC 17.19±0.39 mmol/L, P<0.0001 for both, respectively). In conclusion, LIPC enhanced repeated sprint cycling performance during the initial phase, beyond what could be accounted for entirely by a psychophysiological effect. The improvement associated with RIPC, however, did not surpass the effect of a placebo intervention.

A Double-Blind, Randomized, Placebo-Controlled Pilot Study examining an Oxygen Nanobubble Beverage for 16.1-km Time Trial and Repeated Sprint Cycling Performance

There is growing interest of ergogenic aids that deliver supplemental oxygen during exercise and recovery, however, breathing supplemental oxygen via specialist facemasks is often not feasible. Therefore, this study investigated the effect of an oxygen-nanobubble beverage during submaximal and repeated sprint cycling. In a double-blind, randomized, placebo-controlled study, 10 male cyclists (peak aerobic capacity, 56.9 ± 6.1 mL·kg−1·min−1; maximal aerobic power, 385 ± 25 W) completed submaximal or maximal exercise after consuming an oxygen-nanobubble (O2) or placebo (PLA) beverage. Submaximal trials comprised 30-min of steady-state cycling at 60% peak aerobic capacity and 16.1-km time-trial (TT). Maximal trials involved 4 × 30 s Wingate tests interspersed by 4-min recovery. Time-to-completion during the 16.1-km TT was 2.4% faster after O2 compared with PLA (95% CI = 0.7–4.0%, p = 0.010, d = 0.41). Average power for the 16.1-km TT was 4.1% higher for O2 vs. PLA (95% CI = 2.1–7.3%, p = 0.006, d = 0.28). Average peak power during the repeated Wingate tests increased by 7.1% for O2 compared with PLA (p = 0.002, d = 0.58). An oxygen-nanobubble beverage improves performance during submaximal and repeated sprint cycling, therefore may provide a practical and effective ergogenic aid for competitive cyclists.

Listening to Fast-Tempo Music During a Post-Exercise Passive Rest Period Improved Subsequent Sprint Cycling.

Listening to music during active recovery between exercise bouts has been found to help maintain high levels of exercise performance; however, the effect of listening to music alone with no exercise while resting passively has not been elucidated. We examined whether listening to music during static (passive) recovery affects subsequent repeated sprint performances and/or psychological and physiological responses in healthy young males. Twelve healthy young male athletes completed two consecutive sets of 7 × 7 second maximal cycling sprints with a 30-second rest interval between the sprints. During a 15-minute interval between the sets, the participants rested passively while listening to fast-tempo (Fast, 130 bpm), slow-tempo (Slow, 70 bpm) music, or no music (Con). We assessed affective valence and arousal using the Affect Grid. The valence and arousal scores immediately after listening to fast-tempo music were significantly higher than those in the no music condition. Mean and peak power outputs during the second set after listening to fast-tempo music were significantly higher compared to those after the Slow and Con conditions (both adjusted p < .05). Moreover, the changes in exercise performances between the first and second set were significantly associated with changes in the arousal score induced by the music conditions, but not with changes in the valence score. These results suggested that listening to fast-tempo songs during passive recovery between the exercises improved subsequent repeated sprint cycling performance in physically active males. This type of rapid exercise recovery might be useful for competitive athletes, such as judo, track and fields, and swimming races.

The Effects Of Beetroot And Tart Cherry Supplementation On Repeated Sprint Performance

PURPOSE: In recent years, sports supplements have been of interest to athletes as a possible way to increase performance. Two supplements of high interest are beetroot (BR) and tart cherry (TC) juice. BR is known to have an ergogenic effect due to its high nitrate contents, helping to vasodilate blood vessels in times of low oxygen availability. TC is known for its anti-oxidative and anti-inflammatory properties, which is shown to benefit athletes as well. Therefore, this study aimed to investigate whether beetroot and tart cherry supplementation would improve repeated sprint performance in healthy individuals. METHODS: Using a randomized cross-over, double-blind, placebo-controlled design, 12 healthy individuals ( 4 females and 8 males, 24.4 ± 2.7 years) were consumed BR, TC, and placebo capsules separately to determine the effects of these supplements on repeated sprint cycling performance. Participants completed a baseline sprint test, including a 5-minute warm-up, followed by six 10 second sprints (6x10) interspersed by a minute passive recovery. Participants received capsule contained 500mg of powder. In total, 2000mg of BR, TC, and placebo were separately consumed for four days prior to testing day. Peak power (W) and average power (W) were measured using Monark bike instrument data. Blood pressure was taken before and following the test. Lactate testing was done prior to the test, immediately after, as well as 10 minutes following the cycling sprint protocol. RESULTS: Results showed that the average power was significantly higher in BR (491.5±78 W) and TC (497±82 W) against PL (477±90 W), while no difference was found between BR and TC conditions. Furthermore, the lactate level at 10 minutes following the test was significantly lower in BR (10.3±0.67 mmol/l) versus TC (11.08±1.23 mmol/l) and PL (11.6±1.12 mmol/l) conditions. There was no significant difference among TC, BR, and PL on peak power. CONCLUSIONS: Our results indicate that while BR and TC supplementation both improved performance at the 10-s repeated cycling sprint, this improvement was only accompanied by differences in lactate levels after the protocol in response to BR supplementation.

Repeated sprint cycling performance is not enhanced by ischaemic preconditioning or muscle heating strategies

ABSTRACT Introduction: Both ischaemic preconditioning (IPC) and muscle heat maintenance can be effective in enhancing repeated-sprint performance (RSA) when applied individually, acting mechanisms of these interventions, however, likely differ. It is unclear if, when combined, these interventions could further improve RSA. Methods: Eleven trained cyclists undertook experimental test sessions, whereby IPC (4 × 5-min at 220 mmHg) and SHAM (4 × 5-min at 20 mmHg) were each performed on two separate visits, each combined with either passive muscle heating or thermoneutral insulation prior to an “all-out” repeated-sprint task (10 × 6-s sprints with 24-s recovery). Primary outcome measures were peak and average power output (W), whist secondary measures were muscular activation and muscular oxygenation, measured via Electromyography (EMG) and Near-infrared spectroscopy (NIRS), respectively. Results: IPC did not enhance peak [6 (−14–26)W; P = 0.62] or average [12 (−7–31)W; P = 0.28] power output versus SHAM. Additionally, no performance benefits were observed when increasing muscle temperature in combination with IPC [5 (−14–19) watts; P = 0.67], or in isolation to IPC [9 (−9–28)W; P = 0.4] versus SHAM. No changes in EMG or microvascular changes were present (P > 0.05, respectively) between conditions. Conclusion: Overall, neither IPC, muscle heating, or a combination of both enhances RSA cycling performance in trained individuals.

Commentary: Active Preconditioning With Blood Flow Restriction or/and Systemic Hypoxic Exposure Does Not Improve Repeated Sprint Cycling Performance.

Commentary: Active Preconditioning With Blood Flow Restriction or/and Systemic Hypoxic Exposure Does Not Improve Repeated Sprint Cycling Performance.

Active Preconditioning With Blood Flow Restriction or/and Systemic Hypoxic Exposure Does Not Improve Repeated Sprint Cycling Performance.

PurposeThe aim of this study was to evaluate the effects of active preconditioning techniques using blood flow restriction or/and systemic hypoxic exposure on repeated sprint cycling performance and oxygenation responses.MethodsParticipants were 17 men; 8 were cycle trained (T: 21 ± 6 h/week) and 9 were untrained but physically active (UT). Each participant completed 4 cycles of 5 min stages of cycling at 1.5 W⋅kg–1 in four conditions [Control; IPC (ischemic preconditioning) with partial blood flow restriction (60% of relative total occlusion pressure); HPC (hypoxic preconditioning) in normobaric systemic hypoxia (FIO2 13.6%); and HIPC (hypoxic and ischemic preconditioning combined)]. Following a 40 min rest period, a repeated sprint exercise (RSE: 8 × 10 s sprints; 20 s of recovery) was performed. Near-infrared spectroscopy parameters [for each sprint, change in deoxyhemoglobin (Δ[HHb]), total hemoglobin (Δ[tHb]), and tissue saturation index (ΔTSI%)] were measured.ResultsTrained participants achieved higher power outputs (+10–16%) than UT in all conditions, yet RSE performance did not differ between active preconditioning techniques in the two groups. All conditions induced similar sprint decrement scores during RSE in both T and UT (16 ± 2 vs. 23 ± 9% in CON; 17 ± 3 vs. 19 ± 6% in IPC; 18 ± 5 vs. 20 ± 10% in HPC; and 17 ± 3 vs. 21 ± 5% in HIPC, for T and UT, respectively). During the sprints, Δ[HHb] was larger after IPC than both HPC and CON in T (p < 0.001). The Δ[tHb] was greater after HPC than all other conditions in T, whereas IPC, HPC, and HIPC induced higher Δ[tHb] than CON in UT.ConclusionNone of the active preconditioning methods had an ergogenic effect on repeated sprint cycling performance, despite some specific hemodynamic responses (e.g., greater oxygen extraction and changes in blood volume), which were emphasized in the trained cyclists.

Relationship between skeletal muscle carnosine content and cycling sprint performance

Background: High-intensity exercise is limited by muscle acidosis, among other factors. Supplementation with buffering agents can delay the onset of muscular fatigue and improve performance ( Saunders et al., 2017 , Heibel et al., 2018 ). These include supplements that can increase the extracellular buffering capacity (e.g., sodium bicarbonate, which increases blood bicarbonate) and the intracellular buffering capacity (e.g., beta-alanine, which increases muscle carnosine). Since high-intensity performance has been associated with hydrogen ion buffering capacity ( Rampinini et al., 2009 ), we sought to examine whether pre-exercise blood bicarbonate concentration and muscle carnosine content are associated with repeated-sprint cycling performance. Purpose: To determine the relationship between blood bicarbonate and muscle carnosine of trained cyclists and high-intensity performance during the 4-bout Wingate cycling test. Methods: Forty-one trained male cyclists (age: 35 ± 7 y; weight: 74.7 ± 10.5 kg; height: 1.78 ± 0.08 m) that had been training for at least 2 years (experience: 9 ± 8 years; training hours: 12 ± 6 hours∙week -1 ; training distance: 261 ± 165 km∙week -1 ) participated in the study. Participants were required not to have used supplements containing creatine in the 3 months, or beta-alanine in the 6 months prior to the study. A 4-bout Wingate cycling test (30 s all-out with 3-min passive recovery between bouts) protocol was performed on a mechanically braked cycle-ergometer. Total mechanical work (TMW) was determined for each single bout and for the overall protocol (i.e., the four bouts altogether). Blood samples were taken immediately before and after exercise for the determination of blood pH and bicarbonate using a blood gas analyser (Rapid Point 350, Siemens, Germany). Sample muscles were obtained from the m. vastus lateralis using the biopsy technique; carnosine was determined using tandem liquid chromatography-mass spectrometry (HPLC-ESI + -MS/MS) as described by Carvalho et al. (2018) . Data are presented as mean ± 1 standard deviation. The relationship between blood bicarbonate and muscle carnosine variables and exercise performance was determined using Pearson’s correlation and a paired t-test was used to compare blood variables before and after the exercise test. All data were analysed using GraphPad 6.0 and statistical signii¬cance was accepted at p 0.05; Figure 2). A significant decrease in blood bicarbonate (rest 29.6 ± 2.1 vs post 14.6 ± 3.7 mmol∙L -1 ; p < 0.0001) and blood pH (rest 7.353 ± 0.035 vs post 7.048 ± 0.094; p < 0.0001; Figure 3) was shown following the cycling protocol. Discussion: This study showed no association between repeated sprint cycling performance and blood bicarbonate or muscle carnosine, suggesting that neither initial blood bicarbonate concentration nor muscle carnosine content influences performance during this type of exercise. Interestingly, sodium bicarbonate and beta-alanine supplementation have previously been shown to improve repeated Wingate performance, particularly in the final bouts ( Tobias et al., 2013 , Artioli et al., 2007 , Painelli et al., 2014 ). Since fatigue during high-intensity activity is multifactorial, this may indicate that small baseline variations in blood bicarbonate and muscle carnosine are not large enough to translate into performance benefits. It is likely that supplementation with sodium bicarbonate and beta-alanine, on the other hand, result in changes of sufficient magnitude to delay fatigue and improve performance. Conclusions: The current study showed that initial levels of blood bicarbonate and muscle carnosine were not associated with repeated Wingate performance, suggesting that these variables are not good predictors of cycling sprint performance.

The effects of hyperoxia on repeated sprint cycling performance & muscle fatigue

ObjectivesHyperoxia (>21% oxygen) can evoke performance improvements in aerobic and anaerobic exercise. The aims of the current study were to determine the effects of breathing hyperoxic gas (fraction of inspired oxygen [FiO2] 1.00) on repeated cycle performance, and to assess the nature and extent of fatigue after intermittent sprinting. Design & methodsTesting (n=14 males) comprised two visits to the laboratory. Each session involved 10×15s repeated cycle sprints breathing FiO2 1.00 (hyperoxia) or FiO2 0.21 (normoxia). Muscle fatigue was measured pre and post sprints using Maximal Voluntary Contraction (MVC), voluntary activation (VA) and potentiated doublet twitch (PTF). Blood lactate (BLa) was taken between sprints.Paired samples t-tests were used to examine difference between conditions in power output (peak and mean Watts) and BLa. Two-way ANOVA was used to examine fatigue variables pre and post sprints according to condition. ResultsMean power output was 4% greater in hyperoxia (p<0.01), with no difference in peak power (p>0.05). There was a significant increase in BLa in hyperoxia compared with normoxia (p<0.01) in sprints 4 and 8, as well as meaningful difference in sprints 4–10. There was no significant difference in fatigue factors (MVC, VA and PTF) (p>0.05) in response to the cycling, although a large drop in PTF occurred in both conditions. ConclusionHyperoxia can elicit improvements in mean cycling power, with no significant change in post exercise muscle fatigue. Hyperoxia as a training aid may provide performance enhancing effects during repeated sprint cycling by reducing concurrent muscle fatigue, primarily via peripheral factors.

Differences in the Repeated Sprint Performance Between the First and Latter Halves of Trials Under Conditions of Several Thermal States in Exercising Muscles.

Inoue, K, Yamashita, N, Kume, M, and Yoshida, T. Differences in the repeated sprint performance between the first and latter halves of trials under conditions of several thermal states in exercising muscles. J Strength Cond Res 35(3): 782-790, 2021-The purpose of this study was to determine whether the effects of thermal states in exercising muscle on repeated sprint cycling (RSC) performance differ between the first and latter half of trials. Nine male subjects performed 8 × 8 seconds of RSC with a 40-second rest period. The subjects wore water-perfused trousers with water at 6° C (COLD), 17° C (COOL), 30° C (WARM), or 44° C (HOT). During the first half of trials, the peak power output (PPO), mean power output (MPO), and sum of work output (SWO) were significantly (p < 0.05) greater under the WARM and HOT conditions than under the COLD and COOL conditions, and a difference in the PPO and MPO between WARM and HOT was noted in the second sprint bout during the first half of the exercise. However, during the latter half of trials, there was no significant difference in the PPO, MPO, and SWO among the 4 conditions. The tympanic temperature (Tty) was significantly elevated under the HOT condition but fell under the COLD and COOL conditions, whereas the Tty under the WARM condition did not change significantly (p < 0.05) during the experiment. The total sweat loss was significantly (p < 0.05) greater in the HOT condition than in the other conditions. These results suggest that the effect of thermal states in exercising muscle on the RSC performance is greater in the first half of exercise than in the latter half, possibly because of the elevation of the core temperature and sweat loss under HOT conditions.

Creatine-electrolyte supplementation improves repeated sprint cycling performance: A double blind randomized control study

BackgroundCreatine supplementation is recommended as an ergogenic aid to improve repeated sprint cycling performance. Furthermore, creatine uptake is increased in the presence of electrolytes. Prior research examining the effect of a creatine-electrolyte (CE) supplement on repeated sprint cycling performance, however, did not show post-supplementation improvement. The purpose of this double blind randomized control study was to investigate the effect of a six-week CE supplementation intervention on overall and repeated peak and mean power output during repeated cycling sprints with recovery periods of 2 min between sprints.MethodsPeak and mean power generated by 23 male recreational cyclists (CE group: n = 12; 24.0 ± 4.2 years; placebo (P) group: n = 11; 23.3 ± 3.1 years) were measured on a Velotron ergometer as they completed five 15-s cycling sprints, with 2 min of recovery between sprints, pre- and post-supplementation. Mixed-model ANOVAs were used for statistical analyses.ResultsA supplement-time interaction showed a 4% increase in overall peak power (pre: 734 ± 75 W; post: 765 ± 71 W; p = 0.040; ηp2 = 0.187) and a 5% increase in overall mean power (pre: 586 ± 72 W; post: 615 ± 74 W; p = 0.019; ηp2 = 0.234) from pre- to post-supplementation for the CE group. For the P group, no differences were observed in overall peak (pre: 768 ± 95 W; post: 772 ± 108 W; p = 0.735) and overall mean power (pre: 638 ± 77 W; post: 643 ± 92 W; p = 0.435) from pre- to post-testing. For repeated sprint analysis, peak (pre: 737 ± 88 W; post: 767 ± 92 W; p = 0.002; ηp2 = 0.380) and mean (pre: 650 ± 92 W; post: 694 ± 87 W; p < 0.001; ηp2 = 0.578) power output were significantly increased only in the first sprint effort in CE group from pre- to post-supplementation testing. For the P group, no differences were observed for repeated sprint performance.ConclusionA CE supplement improves overall and repeated short duration sprint cycling performance when sprints are interspersed with adequate recovery periods.

Sprint Cycling Performance Improvement Post-Creatine Supplementation is Associated with Increase in Lean Body Mass

Creatine supplementation is recommended as an ergogenic aid to improve repeated cycling sprint performance. Creatine absorption is increased in the presence of electrolytes. Research examining the effect of a creatine-electrolyte (CE) supplement on repeated sprint cycling performance failed to show post-supplementation improvement. These results can be attributed to inadequate recovery periods between repeated sprints. A recovery of 2-minutes is adequate for phosphocreatine resynthesis and may allow for maximal performance during repeated cycling sprints. PURPOSE: To investigate the effect of a 6-week CE supplementation intervention on peak power and average work performed during repeated cycling sprints interspersed with 2-minute recovery periods. METHODS: Peak power and average work performed by 38 recreational cyclists (CE group: n = 17; 23.4 ± 4.0 years; placebo (P) group: n = 18; 23.4 ± 4.0 years) were measured on a Velotron ergometer as they completed five, 15-s cycling sprints, with two minutes of recovery between sprints, pre- and post-supplementation. Peak power was the highest overall power measured across the sprints. Average work was the mean of total work performed across the five sprints. Participants’ body composition was estimated using three site skinfold measurements. Mixed-model ANOVAs were used for statistical analyses. RESULTS: For almost all participants, the peak power was generated during the first sprint. A supplement-time interaction showed a 4% increase in peak power (27 W; p < 0.001) and a 5% increase in average work (376 J; p < 0.001) from pre- to post-supplementation for the CE group. For the P group, no differences were observed in these variables from pre- to post-testing. Similarly, the lean body mass increased by 2% (1.4 kg; p = 0.001) from pre- to post-testing for the CE group, whereas no differences were found for the P group (supplement-time interaction; p = 0.001). For the CE group, a modest association (r = 0.626; p = 0.007) was observed between the increases in peak power and lean body mass from pre- to post-supplementation. CONCLUSION: A CE supplement improves repeated short duration cycling sprint performance when sprints are interspersed with adequate recovery periods. Additionally, the ergogenic effect of CE supplement is associated with an increase in lean body mass.

Endurance, aerobic high-intensity, and repeated sprint cycling performance is unaffected by normobaric "Live High-Train Low": a double-blind placebo-controlled cross-over study.

The aim was to investigate whether 6weeks of normobaric "Live High-Train Low" (LHTL) using altitude tents affect highly trained athletes incremental peak power, 26-km time-trial cycling performance, 3-min all-out performance, and 30-s repeated sprint ability. In a double-blinded, placebo-controlled cross-over design, seven highly trained triathletes were exposed to 6weeks of normobaric hypoxia (LHTL) and normoxia (placebo) for 8h/day. LHTL exposure consisted of 2 weeks at 2500m, 2weeks at 3000m, and 2weeks at 3500m. Power output during an incremental test, ~26-km time trial, 3-min all-out exercise, and 8 × 30s of all-out sprint was evaluated before and after the intervention. Following at least 8weeks of wash-out, the subjects crossed over and repeated the procedure. Incremental peak power output was similar after both interventions [LHTL: 375 ± 74 vs. 369 ± 70W (pre-vs-post), placebo: 385 ± 60 vs. 364 ± 79W (pre-vs-post)]. Likewise, mean power output was similar between treatments as well as before and after each intervention for time trial [LHTL: 257 ± 49 vs. 254 ± 54W (pre-vs-post), placebo: 267 ± 57 vs. 267 ± 52W (pre-vs-post)], and 3-min all-out [LHTL: 366 ± 68 vs. 369 ± 72W (pre-vs-post), placebo: 365 ± 66 vs. 355 ± 71W (pre-vs-post)]. Furthermore, peak- and mean power output during repeated sprint exercise was similar between groups at all time points (n = 5). In conclusion, 6weeks of normobaric LHTL using altitude tents simulating altitudes of 2500-3500m conducted in a double-blinded, placebo-controlled cross-over design do not affect power output during an incremental test, a ~26-km time-trial test, or 3-min all-out exercise in highly trained triathletes. Furthermore, 30s of repeated sprint ability was unaltered.

Coffee and Caffeine Ingestion Have Little Effect on Repeated Sprint Cycling in Relatively Untrained Males.

The present study investigated the effect of ingesting caffeine-dose-matched anhydrous caffeine or coffee on the performance of repeated sprints. Twelve recreationally active males (mean ± SD age: 22 ± 2 years, height: 1.78 ± 0.07 m, body mass: 81 ± 16 kg) completed eighteen 4 s sprints with 116 s recovery on a cycle ergometer on four separate occasions in a double-blind, randomised, counterbalanced crossover design. Participants ingested either 3 mg·kg−1 of caffeine (CAF), 0.09 g·kg−1 coffee, which provided 3 mg·kg−1 of caffeine (COF), a taste-matched placebo beverage (PLA), or a control condition (CON) 45 min prior to commencing the exercise protocol. Peak and mean power output and rating of perceived exertion (RPE) were recorded for each sprint. There were no significant differences in peak power output (CAF: 949 ± 199 W, COF: 949 ± 174 W, PLA: 971 ± 149 W and CON: 975 ± 170 W; p = 0.872; = 0.02) or mean power output (CAF: 873 ± 172 W, COF: 862 ± 44 W, PLA: 887 ± 119 W and CON: 892 ± 143 W; p = 0.819; = 0.03) between experimental conditions. Mean RPE was similar for all trials (CAF: 11 ± 2, COF: 11 ± 2, PLA: 11 ± 2 and CON: 11 ± 2; p = 0.927; = 0.01). Neither the ingestion of COF or CAF improved repeated sprint cycling performance in relatively untrained males.

The Effect of Ischemic Preconditioning on Repeated Sprint Cycling Performance.

Ischemic preconditioning enhances exercise performance. We tested the hypothesis that ischemic preconditioning would improve intermittent exercise in the form of a repeated sprint test during cycling ergometry. In a single-blind, crossover study, 14 recreationally active men (mean ± SD age, 22.9 ± 3.7 yr; height, 1.80 ± 0.07 m; and mass, 77.3 ± 9.2 kg) performed twelve 6-s sprints after four 5-min periods of bilateral limb occlusion at 220 mm Hg (ischemic preconditioning) or 20 mm Hg (placebo). Ischemic preconditioning resulted in a 2.4% ± 2.2%, 2.6% ± 2.7%, and 3.7% ± 2.4% substantial increase in peak power for sprints 1, 2, and 3, respectively, relative to placebo, with no further changes between trials observed for any other sprint. Similar findings were observed in the first three sprints for mean power output after ischemic preconditioning (2.8% ± 2.5%, 2.6% ± 2.5%, and 3.4% ± 2.1%, for sprints 1, 2, and 3, respectively), relative to placebo. Fatigue index was not substantially different between trials. At rest, tissue saturation index was not different between the trials. During the ischemic preconditioning/placebo stimulus, there was a -19.7% ± 3.6% decrease in tissue saturation index in the ischemic preconditioning trial, relative to placebo. During exercise, there was a 5.4% ± 4.8% greater maintenance of tissue saturation index in the ischemic preconditioning trial, relative to placebo. There were no substantial differences between trials for blood lactate, electromyography (EMG) median frequency, oxygen uptake, or rating of perceived exertion (RPE) at any time points. Ischemic preconditioning improved peak and mean power output during the early stages of repeated sprint cycling and may be beneficial for sprint sports.

The influence of acetaminophen on repeated sprint cycling performance

The aim of this study was to investigate the effect of acetaminophen on repeated sprint cycling performance. Nine recreationally active male participants completed a graded exercise test, a familiarisation set of Wingate Anaerobic Tests (WAnTs) and two experimental sets of WAnTs (8 × 30 s sprints, 2 min active rest intervals). In the experimental WAnTs, participants ingested either 1.5 g acetaminophen or a placebo in a double-blind, randomised, crossover design. During the WAnT trials, participants provided ratings of perceived pain 20 s into each sprint. Mean and peak power output and heart rate were recorded immediately following each sprint, and percentage decrement in mean power output was subsequently calculated. Participants cycled at a significantly greater mean power output over the course of 8 WAnTs (p < 0.05) following the ingestion of acetaminophen (391 ± 74 vs. 372 ± 90 W), due to a significantly greater mean power output during sprints 6, 7 and 8 (p < 0.05). Percentage decrements in mean power output were also significantly reduced (p < 0.05) following acetaminophen ingestion (17 ± 14 vs. 24 ± 17 %). No significant differences in peak power output, perceived pain or heart rate were observed between conditions. Acetaminophen may have improved performance through the reduction of pain for a given work rate, thereby enabling participants to exercise closer to a true physiological limit. These results suggest that exercise may be regulated by pain perception, and that an increased pain tolerance can improve exercise performance.

Hot conditions improve power output during repeated cycling sprints without modifying neuromuscular fatigue characteristics

This study investigated the effect of hot conditions on repeated sprint cycling performance and post-exercise alterations in isometric knee extension function. Twelve physically active participants performed 10×6-s "all-out" sprints on a cycle ergometer (recovery=30s), followed 6min later by 5×6-s sprints (recovery=30s) in either a neutral (24°C/30%rH) or a hot (35°C/40%rH) environment. Neuromuscular tests including voluntary and electrically evoked isometric contractions of the knee extensors were performed before and after exercise. Average core temperature during exercise was higher (38.0±0.1 vs. 37.7±0.1°C, respectively; P<0.05) in hot versus neutral environments. Peak power output decreased (-17.9% from sprint 1 to sprint 10 and -17.0% from sprint 11 to sprint 15; P<0.001) across repetitions. Average peak power output during the first ten sprints was higher (+3.1%; P<0.01) in the hot ambient temperature condition. Maximal strength (-12%) and rate of force development (-15 to -26%, 30-200ms from the onset of contraction) decreased (P<0.001) during brief contractions after exercise, irrespectively of the ambient temperature. During brief maximal contractions, changes in voluntary activation (~80%) were not affected by exercise or temperature. Voluntary activation declined (P<0.01) during the sustained contraction, with these reductions being more pronounced (P<0.05) after exercise but not affected by the ambient temperature. Resting twitch amplitude declined (P<0.001) by ~42%, independently of the ambient temperature. In conclusion, heat exposure has no effect on the pattern and the extent of isometric knee extensor fatigue following repeated cycling sprints in the absence of hyperthermia.

The Effects of Different Recovery Intervals on Repeated Sprint Cycling Performance after Caffeine Ingestion

The Effects of Different Recovery Intervals on Repeated Sprint Cycling Performance after Caffeine Ingestion

Point: Positive effects of intermittent hypoxia (live high:train low) on exercise performance are mediated primarily by augmented red cell volume

Point: Positive effects of intermittent hypoxia (live high:train low) on exercise performance are mediated primarily by augmented red cell volume