Science
The research the BLOCKS assistant answers from: 1,118 studies and 81 guides, each graded for how strong the evidence is and who it was measured on, with a link to the original paper.
139 entries in Endurance physiology
B+Same rider, same watts, same fluid replacement: heart rate drifted 11% and VO2max fell 15% at 35 °C, while at 22 °C it drifted 2% and VO2max did not significantly changeThe environment, not the athlete, wrote most of the numberLafrenz 2008C+Cardiovascular drift begins after about 10 min of prolonged moderate exercise, and the heart-rate rise is not noise: it comes with a genuine fall in maximal oxygen uptake, so the same watts become a harder effortWingo 2012BDoes leg strength relate to W′?In 11 elite male cyclists, knee-extensor max torque tracked W′ (r = 0.87; our 95% CI 0.57-0.97), thigh volume borderline (r = 0.60, p = 0.05), CP neither. Correlation only: strength-for-W′ is…Kordi 2018BIs holding a weight harder than pushing a wall?At 80% MVC in 10 adults, a held elbow position stayed still 19 s vs 41 s when pushing; total time at that force differed less (50 vs 59 s). One small arm study.Schaefer & Bittmann 2017BSex differences in durability following heavy intensity cycling exercise in trained athletesAfter 90 min at 110% of GET on water only, power at the first threshold fell 16% in men and 2% in women, while peak power, VO2peak and neuromuscular function fell alikePastorio 2026BGraded carbohydrate ingestion up to 120 g·h−1 attenuates the reduction in critical power following 3 h of moderate-intensity exercise in a dose-dependent mannerNorte 2026BAccelerating endogenous carbohydrate oxidation impairs durability of the moderate-to-heavy intensity transitionMaunder 2026BDurability improved similarly after 10 weeks of low-intensity (6.8 h/week) or high-intensity (1.6 h/week) cycling in sedentary and recreationally active adults, measured over a 3-h ride at 48% VO2max; only high-intensity training raised VO2max, and the changes in drift were smallMatomäki 2023BDurability — how to measure it: the fatiguing protocol shapes the result (higher relative intensity and longer duration deteriorate baseline measures more), and nutrition and environment must be controlled for a durability number to be repeatable or comparableHunter 2025B+"Much Ado About Zone 2" — a narrative review from the Gurd and Gibala groups: current evidence does not support Zone 2 as the optimal intensity for improving mitochondrial or fatty-acid oxidative capacity; the popular claim rests largely on observational data from elite endurance athletes, and higher intensities matter more at lower training volumesStoroschuk 2025B+3 months of HIIT vs moderate-intensity continuous training (MICT) in obese adults: VO2peak +16% vs +6%; maximal fat oxidation rose only after HIIT; mitochondrial respiration rose in both (+36% vs +67%, no significant difference); after 4 months of follow-up only the HIIT group kept higher VO2peak and fat oxidationVaccari 2020C+Respiratory Frequency during Exercise: The Neglected Physiological MeasureA Perspective article: unlike heart rate, VO2 and blood lactate, respiratory frequency (fR) is strongly associated with perceived exertion across many exercise paradigms and under muscle fatigue…Nicolò 2017BRespiratory frequency is strongly associated with perceived exertion during time trials of different duration9 well-trained male cyclists, self-paced 10-, 20- and 30-min time trials: RPE and breathing rate (fR) rose almost linearly and, on relative time, followed the same course in every trial, while minute…Nicolò 2015BRiding in 5-minute reps with 1-minute rests, trained cyclists held 17 W more at their lactate steady state and lasted 24% longer than in continuous ridingA result that did not repeat for duration in runnersGrossl 2012B+At the same power and the same 30 minutes of work, breaking the ride every 5 minutes with a 30–90-second pause lowered lactate by 1–1.5 mmol/L and removed its drift; the lactate steady state then sits 22–32 W higherBeneke 2003B+In 580 competitive cyclists the best power-based VO2max equation still had 95% limits of agreement of about ±12 mL/kg/min in men; within a trained group power explains under half of the varianceJurov 2023B+External validation: the 5-minute-power VO2max equation underestimated measured VO2max by 6.6 mL/kg/min on average, with limits of agreement from −17.2 to +3.8Borszcz 2024BIn 46 road cyclists VO2max was predicted from best 5-minute power as 16.6 + 8.87 × W/kg, explaining 61–77% of the variance when taken from a field-style 5-minute testSitko 2022BMuscle efficiency improves over time in world-class cyclistsSantalla 2009B+Long-Term Development of Training Characteristics and Performance-Determining Factors in Elite/International and World-Class Endurance Athletes: A Scoping ReviewStaff 2023B+Elite Aerobic Endurance Performance: Is It Really Related to Lactate Threshold Expressed Relative to Peak Oxygen Uptake?Johansen 2025C+Fractional Utilization of V̇O2maxA Key Performance Determinant in Endurance Sports?Sondermann 2026C+The talk test: a useful tool for prescribing and monitoring exercise intensityReed & Pipe 2014BConsistency of the talk test for exercise prescriptionPersinger 2004BCentral and peripheral contributions to neuromuscular fatigue induced by a 24-h treadmill runMartin 2010BRelationship between run times to exhaustion at 90, 100, 120, and 140% of vVO2max and velocity expressed relatively to critical velocity and maximal velocityBlondel 2001BAnaerobic Speed Reserve: A Key Component of Elite Male 800-m RunningSandford 2019BThe Reliability and Validity of the 3-min All-out Cycling Critical Power TestWright 2017BA Single-Visit Field Test of Critical SpeedGalbraith 2014BIs the Functional Threshold Power a Valid Surrogate of the Lactate Threshold?Valenzuela 2018BA 3-min all-out cycling test is sensitive to a change in critical powerVanhatalo 2008BFlat and Uphill Climb Time Trial Performance Prediction in Elite Amateur CyclistsAntón 2007BValidation of a Mathematical Model for Road Cycling PowerMartin 1998BThe Effect of the Aerodynamic Time-Trial Position on Gross Efficiency and Self-Paced Time-Trial PerformanceFennell 2020COptimal Cycling Time Trial Position Models: Aerodynamics versus Power Output and Metabolic EnergyFintelman 2014C+Scientific Approach to the 1-h Cycling World Record: A Case StudyPadilla 2000BIntensity and Load Characteristics of Professional Road Cycling: Differences Between Men's and Women's RacesSanders 2019C+Distribution of Power Output When Establishing a Breakaway in CyclingAbbiss 2013BPower Output during Women's World Cup Road Cycle RacingEbert 2005CMetabolic Factors Limiting Performance in Marathon RunnersRapoport 2010