The science library
No black-box scores. Every number has a source.
QuikShift doesn't invent metrics. Each one is built on published sport science — listed below with a link to the original work. The library is maintained: as the engine grows and new research lands, this page keeps up.
Power & critical power
- Monod & Scherrer (1965) Peer-reviewed The work capacity of a synergic muscular group Ergonomics Critical Power (CP) and W′ — the power you can hold vs. the battery above it.
- Skiba, Chidnok, Vanhatalo & Jones (2012) Peer-reviewed Modeling the expenditure and reconstitution of work capacity above critical power Medicine & Science in Sports & Exercise W′ balance — how much of your anaerobic reserve is left, second by second.
- Poole, Burnley, Vanhatalo, Rossiter & Jones (2016) Peer-reviewed Critical Power: an important fatigue threshold in exercise physiology Medicine & Science in Sports & Exercise Why critical power — not an arbitrary %FTP — marks the heavy/severe boundary behind the CP/W′ curve.
- Jones, Vanhatalo, Burnley, Morton & Poole (2010) Peer-reviewed Critical power: implications for determination of V̇O2max and exercise tolerance Medicine & Science in Sports & Exercise Fitting CP/W′ from maximal efforts and predicting time-to-exhaustion on the power-duration curve.
- Wong, Burnley, Mauger et al. (2023) Peer-reviewed Functional threshold power is not a valid marker of the maximal metabolic steady state Journal of Sports Sciences Why eFTP is shown as a trackable trend, not an exact physiological threshold.
Training load & form
- Allen & Coggan (2010) Reference text Training and Racing with a Power Meter (2nd ed.) VeloPress Normalized Power, Intensity Factor, Variability Index, TSS, and the PMC.
- Banister, Calvert, Savage & Bach (1975) Peer-reviewed A systems model of training for athletic performance Australian Journal of Sports Medicine Fitness–fatigue (impulse–response): CTL, ATL and TSB — your form curve.
- Gabbett (2016) Peer-reviewed The training—injury prevention paradox: should athletes be training smarter and harder? British Journal of Sports Medicine The acute:chronic workload ratio behind the load-spike warning — chronic fitness protects, rapid spikes injure.
- Hulin, Gabbett, Lawson, Caputi & Sampson (2016) Peer-reviewed The acute:chronic workload ratio predicts injury: high chronic workload may decrease injury risk British Journal of Sports Medicine Quantifies why the replan refuses to cram missed load — a high acute:chronic ratio sharply raises injury risk.
- Foster, Florhaug, Franklin et al. (2001) Peer-reviewed A new approach to monitoring exercise training Journal of Strength and Conditioning Research Session-RPE load — a device-free way to feed CTL/ATL/TSB when power or HR is missing.
- Bosquet, Montpetit, Arvisais & Mujika (2007) Peer-reviewed Effects of tapering on performance: a meta-analysis Medicine & Science in Sports & Exercise The pre-race taper template — cut volume ~40–60% over two weeks while holding intensity.
- Mujika & Padilla (2003) Peer-reviewed Scientific bases for precompetition tapering strategies Medicine & Science in Sports & Exercise Why form (TSB) peaks when fatigue clears faster than fitness during a taper.
- Rønnestad et al. (2019) Peer-reviewed Block periodization of endurance training – a systematic review and meta-analysis Open Access Journal of Sports Medicine Concentrating intensity into focused blocks rather than smearing it evenly across every week.
Intensity distribution
- Seiler (2010) Peer-reviewed What is best practice for training intensity and volume distribution in endurance athletes? Int. Journal of Sports Physiology & Performance Polarized vs. threshold distribution and the "grey-zone" warning.
- Stöggl & Sperlich (2014) Peer-reviewed Polarized training has greater impact on key endurance variables than threshold, high intensity, or high volume training Frontiers in Physiology Evidence the session ladder should lean on mostly-easy plus targeted-hard, not a tempo-heavy diet.
- Rosenblat, Perrotta & Vicenzino (2019) Peer-reviewed Polarized vs. threshold training intensity distribution on endurance sport performance: a systematic review and meta-analysis of RCTs Journal of Strength and Conditioning Research Meta-analytic support for capping time-in-Tempo in favour of a polarized split.
Thresholds & physiology
- Faude, Kindermann & Meyer (2009) Peer-reviewed Lactate threshold concepts: how valid are they? Sports Medicine Why time-in-zone boundaries and eFTP track the second (MLSS-related) threshold.
- Bacon, Carter, Ogle & Joyner (2013) Peer-reviewed VO2max trainability and high intensity interval training in humans: a meta-analysis PLoS ONE Realistic ceilings on VO2max improvement when reading a fitness-trend block.
- Maunder, Seiler, Mildenhall, Kilding & Plews (2021) Peer-reviewed The importance of 'durability' in the physiological profiling of endurance athletes Sports Medicine Durability — reading late-activity decoupling and drift as resistance to fatigue.
- Jones (2024) Peer-reviewed The fourth dimension: physiological resilience as an independent determinant of endurance exercise performance The Journal of Physiology Treating late-stage fade as a fourth axis of the athlete profile, not noise.
Recovery & readiness
- Coyle & González-Alonso (2001) Peer-reviewed Cardiovascular drift during prolonged exercise: new perspectives Exercise and Sport Sciences Reviews Aerobic decoupling (Pw:HR drift) as a durability and fatigue marker.
- Plews, Laursen, Stanley, Kilding & Buchheit (2013) Peer-reviewed Training adaptation and heart rate variability in elite endurance athletes Sports Medicine HRV trend interpretation behind the wellness readiness signals.
- Buchheit (2014) Peer-reviewed Monitoring training status with HR measures: do all roads lead to Rome? Frontiers in Physiology Resting-HR and HRV monitoring methods used on the wellness page.
- Plews, Laursen, Kilding & Buchheit (2012) Peer-reviewed Heart rate variability in elite triathletes, is variation in variability the key to effective training? A case comparison European Journal of Applied Physiology Why the HRV driver uses a 7-day rolling mean and watches day-to-day variation, not single readings.
- Kiviniemi, Hautala, Kinnunen & Tulppo (2007) Peer-reviewed Endurance training guided individually by daily heart rate variability measurements European Journal of Applied Physiology The original evidence that gating hard days on HRV beats a fixed plan — 'readiness disposes'.
- Vesterinen et al. (2016) Peer-reviewed Individual endurance training prescription with heart rate variability Medicine & Science in Sports & Exercise Why high readiness can green-light intensity, not only veto it.
- Javaloyes, Sarabia, Lamberts & Moya-Ramón (2019) Peer-reviewed Training prescription guided by heart-rate variability in cycling International Journal of Sports Physiology and Performance HRV-guided prescription validated in trained cyclists — better timing, not more volume.
- Nuuttila, Nikander, Polomoshnov, Laukkanen & Häkkinen (2017) Peer-reviewed Effects of HRV-guided vs. predetermined block training on performance, HRV and serum hormones International Journal of Sports Medicine Justifies tying the readiness veto to a rolling HRV trend so hard blocks defer when recovery is incomplete.
- Mah, Mah, Kezirian & Dement (2011) Peer-reviewed The effects of sleep extension on the athletic performance of collegiate basketball players Sleep Why banked sleep above baseline lifts readiness, not just deficits lowering it.
- Fullagar, Skorski, Duffield, Hammes, Coutts & Meyer (2015) Peer-reviewed Sleep and athletic performance: the effects of sleep loss on exercise performance, and physiological and cognitive responses to exercise Sports Medicine The sleep-debt penalty in the readiness score — sleep loss hits endurance harder than max strength.
- Saw, Main & Gastin (2016) Peer-reviewed Monitoring the athlete training response: subjective self-reported measures trump commonly used objective measures: a systematic review British Journal of Sports Medicine Why the subjective driver carries real weight — self-report tracks training load more sensitively than objective markers.
- Kellmann, Bertollo, Bosquet et al. (2018) Consensus statement Recovery and performance in sport: consensus statement International Journal of Sports Physiology and Performance The recovery–stress balance behind the Rest/Recovery rungs and the deep-negative-TSB guardrail.
Running & gradient
- Minetti, Moia, Roi, Susta & Ferretti (2002) Peer-reviewed Energy cost of walking and running at extreme uphill and downhill slopes Journal of Applied Physiology Grade-Adjusted Pace (GAP) — comparing hilly and flat running fairly.
- Saunders, Pyne, Telford & Hawley (2004) Peer-reviewed Factors affecting running economy in trained distance runners Sports Medicine Why improving GAP/efficiency can advance pace at the same cost — economy as a performance signal.
- di Prampero, Capelli, Pagliaro et al. (1993) Peer-reviewed Energetics of best performances in middle-distance running Journal of Applied Physiology The energy-cost basis for critical speed, running power, and grade-adjusted pace.
Fueling & hydration
- Jeukendrup (2014) Peer-reviewed A step towards personalized sports nutrition: carbohydrate intake during exercise Sports Medicine Duration-tiered in-session carb targets (~30 / 60 / up to 90 g·h⁻¹) for long sessions.
- Thomas, Erdman & Burke (2016) Consensus statement Nutrition and athletic performance (joint position stand: AND, DC & ACSM) Journal of the Academy of Nutrition and Dietetics Daily carbohydrate and protein targets keyed to training load.
- Impey, Hearris, Hammond et al. (2018) Peer-reviewed Fuel for the work required: a theoretical framework for carbohydrate periodization and the glycogen threshold hypothesis Sports Medicine Train-low on easy days, fuel hard and long sessions fully — periodized fueling.
- Sawka, Burke, Eichner et al. (2007) Consensus statement American College of Sports Medicine position stand: exercise and fluid replacement Medicine & Science in Sports & Exercise Sweat-rate-based hydration with a <2% body-mass-loss guardrail for long or hot sessions.
- Ganio, Klau, Casa, Armstrong & Maresh (2009) Peer-reviewed Effect of caffeine on sport-specific endurance performance: a systematic review Journal of Strength and Conditioning Research Pre-race caffeine (~3–6 mg·kg⁻¹) as a modest, variable ergogenic aid for key efforts.
Heat & altitude
- Périard, Racinais & Sawka (2015) Peer-reviewed Adaptations and mechanisms of human heat acclimation: applications for competitive athletes and sports Scandinavian Journal of Medicine & Science in Sports A 1–2 week heat-acclimation block and heat-derating notes for pace and effort targets.
- Levine & Stray-Gundersen (1997) Peer-reviewed 'Living high-training low': effect of moderate-altitude acclimatization with low-altitude training on performance Journal of Applied Physiology Altitude-camp planning and the post-altitude re-acclimatization caveat on readiness and pace.
Female physiology
- McNulty, Elliott-Sale, Dolan et al. (2020) Peer-reviewed The effects of menstrual cycle phase on exercise performance in eumenorrheic women: a systematic review and meta-analysis Sports Medicine Optional cycle-aware readiness — flags the early follicular phase as a small, individual down-day.
- Hunter & Senefeld (2024) Peer-reviewed Sex differences in human performance The Journal of Physiology Sex-aware benchmark ranges and substrate/fueling notes (greater relative fat oxidation) in analysis.
Health & overtraining
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