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"Critical power"

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https://www.readbyqxmd.com/read/28704307/acute-cardiopulmonary-metabolic-and-neuromuscular-responses-to-severe-intensity-intermittent-exercises
#1
Felipe D Lisbôa, João A G Raimundo, Amadeo F Salvador, Kayo L Pereira, Tiago Turnes, Fernando Diefenthaeler, Mariana F M de Oliveira, Fabrizio Caputo
The purpose of this study was to compare cardiopulmonary, neuromuscular, and metabolic responses to severe-intensity intermittent exercises with variable or constant work rate. Eleven cyclists (28 ± 5 years; 74 ± 7 kg; 175 ± 5 cm; 63 ± 4 mL·kg·min) performed the following tests until exhaustion on separate days: 1) an incremental test; 2) in random order, two constant work rate tests at 95% and 110% of the peak power for the determination of Critical Power (CP); 3) 2-4 tests for the determination of the highest power that still permits the achievement of maximal oxygen uptake (PHIGH); and 4) two random severe-intensity intermittent exercises...
July 12, 2017: Journal of Strength and Conditioning Research
https://www.readbyqxmd.com/read/28687955/effects-of-recovery-interval-duration-on-the-parameters-of-the-critical-power-model-for-incremental-exercise
#2
Giovanni Vinetti, Nazzareno Fagoni, Anna Taboni, Stefano Camelio, Pietro Enrico di Prampero, Guido Ferretti
INTRODUCTION: We tested the linear critical power ([Formula: see text]) model for discrete incremental ramp exercise implying recovery intervals at the end of each step. METHODS: Seven subjects performed incremental (power increment 25 W) stepwise ramps to subject's exhaustion, with recovery intervals at the end of each step. Ramps' slopes (S) were 0.83, 0.42, 0.28, 0.21, and 0.08 W s(-1); recovery durations (t r) were 0 (continuous stepwise ramps), 60, and 180 s (discontinuous stepwise ramps)...
July 7, 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28686083/ischemic-preconditioning-enhances-critical-power-during-a-3-minute-all-out-cycling-test
#3
Patrick J Griffin, Richard A Ferguson, Conor Gissane, Stephen J Bailey, Stephen D Patterson
This study tested the hypothesis that ischemic preconditioning (IPC) would increase critical power (CP) during a 3 minute all-out cycling test. Twelve males completed two 3 minute all-out cycling tests, in a crossover design, separated by 7 days. These tests were preceded by IPC (4 x 5 minute intervals at 220 mmHg bilateral leg occlusion) or SHAM treatment (4 x 5 minute intervals at 20 mmHg bilateral leg occlusion). CP was calculated as the mean power output during the final 30 s of the 3 minute test with W' taken as the total work done above CP...
July 7, 2017: Journal of Sports Sciences
https://www.readbyqxmd.com/read/28627041/prior-exercise-speeds-pulmonary-oxygen-uptake-kinetics-and-increases-critical-power-during-supine-but-not-upright-cycling
#4
Richie P Goulding, Denise M Roche, Simon Marwood
Critical power (CP) is a fundamental parameter defining high-intensity exercise tolerance and is related to the time constant of phase II pulmonary oxygen uptake kinetics (τV̇O2 ). To test the hypothesis that this relationship is causal we determined the impact of prior exercise ("priming") on CP and τV̇O2 in the upright and supine positions. 17 healthy men were assigned to either upright or supine exercise groups, whereby CP, τV̇O2 and muscle deoxyhaemoglobin kinetics (τ[HHb] ) were determined via constant-power tests to exhaustion at four work-rates with (primed) and without (control) priming exercise at ∼31%Δ...
June 19, 2017: Experimental Physiology
https://www.readbyqxmd.com/read/28617848/effect-of-caffeine-ingestion-on-anaerobic-capacity-quantified-by-different-methods
#5
Lucyana Arcoverde, Rodrigo Silveira, Fabiano Tomazini, André Sansonio, Romulo Bertuzzi, Adriano Eduardo Lima-Silva, Victor Amorim Andrade-Souza
We investigated whether caffeine ingestion before submaximal exercise bouts would affect supramaximal oxygen demand and maximal accumulated oxygen deficit (MAOD), and if caffeine-induced improvement on the anaerobic capacity (AC) could be detected by different methods. Nine men took part in several submaximal and supramaximal exercise bouts one hour after ingesting caffeine (5 mg·kg-1) or placebo. The AC was estimated by MAOD, alternative MAOD, critical power, and gross efficiency methods. Caffeine had no effect on exercise endurance during the supramaximal bout (caffeine: 131...
2017: PloS One
https://www.readbyqxmd.com/read/28607465/spiraling-elliptic-hermite-gaussian-solitons-in-nonlocal-nonlinear-media-without-anisotropy
#6
Guo Liang, Zhiping Dai
We introduce a kind of the spiraling elliptic Hermite-Gaussian solitons in nonlocal nonlinear media without anisotropy, which carries the orbital angular momentum and can rotate in the transverse. The n-th mode of the spiraling elliptic Hermite-Gaussian solitons has n holes nested in the elliptic profile. The analytical spiraling elliptic Hermite-Gaussian solitons solutions are obtained based on the variational approach, which agree well with the numerical simulations. It is found that the critical power and the critical angular velocity for the spiraling elliptic Hermite-Gaussian solitons are the same as the counterpart of the ground mode...
June 12, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28596738/intensity-and-duration-based-options-to-regulate-endurance-training
#7
Peter Hofmann, Gerhard Tschakert
The regulation of endurance training is usually based on the prescription of exercise intensity. Exercise duration, another important variable of training load, is rarely prescribed by individual measures and mostly set from experience. As the specific exercise duration for any intensity plays a substantial role regarding the different kind of cellular stressors, degree, and kind of fatigue as well as training effects, concepts integrating the prescription of both intensity and duration within one model are needed...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28530517/contributions-of-body-composition-characteristics-to-critical-power-and-anaerobic-work-capacity
#8
M Travis Byrd, Jonathan Robert Switalla, Joel E Eastman, Brian J Wallace, Jody L Clasey, Haley C Bergstrom
Critical power (CP) and anaerobic work capacity (AWC) from the CP test represent distinct parameters related to metabolic characteristics of the whole body and active muscle tissue, respectively. PURPOSE: This study examined the contribution of whole body composition characteristics and local lean mass to further elucidate the differences in metabolic characteristics between CP and AWC as they relate to whole body and local factors. METHODS: Fifteen, anaerobically trained males were assessed for whole body (% body fat [%BF] and mineral-free, lean mass [LBM]) and local mineral-free thigh lean mass (TLM) composition characteristic...
May 22, 2017: International Journal of Sports Physiology and Performance
https://www.readbyqxmd.com/read/28530476/time-trials-versus-time-to-exhaustion-tests-effects-on-critical-power-w-and-oxygen-uptake-kinetics
#9
Bettina Karsten, Jonathan Baker, Fernando Naclerio, Andreas Klose, Antonino Bianco, Alfred Nimmerichter
PURPOSE: To investigate single-day time-to-exhaustion (TTE) and time trial (TT) based laboratory tests values of critical power (CP), Wprime (W') and respective oxygen kinetics responses. METHODS: Twelve cyclists performed a maximal ramp test followed by three TTE and three TT efforts interspersed by a 60-min recovery between efforts. Oxygen uptake was measured during all trials. The mean response time (MRT) was calculated as a description of the overall V̇O2 kinetic response from the onset to 2 min of exercise...
May 22, 2017: International Journal of Sports Physiology and Performance
https://www.readbyqxmd.com/read/28479931/cardiorespiratory-fitness-and-aerobic-performance-adaptations-to-a-4-week-sprint-interval-training-in-young-healthy-untrained-females
#10
Mykolas Kavaliauskas, Thomas P Steer, John A Babraj
PURPOSE: The aim of this study was to test the effects of sprint interval training (SIT) on cardiorespiratory fitness and aerobic performance measures in young females. METHODS: Eight healthy, untrained females (age 21 ± 1 years; height 165 ± 5 cm; body mass 63 ± 6 kg) completed cycling peak oxygen uptake ([Formula: see text] peak), 10-km cycling time trial (TT) and critical power (CP) tests pre- and post-SIT. SIT protocol included 4 × 30-s "all-out" cycling efforts against 7 % body mass interspersed with 4 min of active recovery performed twice per week for 4 weeks (eight sessions in total)...
2017: Sport Sciences for Health
https://www.readbyqxmd.com/read/28437928/terahertz-optical-bistability-of-graphene-in-thin-layers-of-dielectrics
#11
Kwang Jun Ahn, Fabian Rotermund
We theoretically studied in terahertz frequency regime optical bistability of graphene placed at the interface between thin dielectric layers. We solved self-consistently the nonlinear wave equations containing the third-order optical conductivity of graphene in four-layer structures and obtained hysteresis response of the transmitted power as a function of the incident power. We numerically observed that the critical powers for the up and down transitions and the Fermi-energy of graphene required for terahertz optical bistability can be reduced by carefully choosing material properties and the thicknesses of dielectric layers...
April 17, 2017: Optics Express
https://www.readbyqxmd.com/read/28388783/the-reliability-and-validity-of-the-3-min-all-out-cycling-critical-power-test
#12
James Wright, Stewart Bruce-Low, Simon A Jobson
Research suggests that critical power (CP) can be estimated from a single 3-min bout of all-out cycling. The purpose of this study was to investigate the reliability and validity of the 3-min all-out cycling test when carried out at a constant cadence (isokinetic) and against a fixed resistance (linear). 12 participants completed 8 tests: 1) a ramp test; 2-4) 3 fixed power tests to calculate CP and W' using the 1/time mathematical model; 5-8) four 3-min all-out tests to calculate EP and WEP; 2 isokinetic and 2 linear tests...
June 2017: International Journal of Sports Medicine
https://www.readbyqxmd.com/read/28386237/prediction-of-critical-power-and-w-in-hypoxia-application-to-work-balance-modelling
#13
Nathan E Townsend, David S Nichols, Philip F Skiba, Sebastien Racinais, Julien D Périard
Purpose: Develop a prediction equation for critical power (CP) and work above CP (W') in hypoxia for use in the work-balance ([Formula: see text]) model. Methods: Nine trained male cyclists completed cycling time trials (TT; 12, 7, and 3 min) to determine CP and W' at five altitudes (250, 1,250, 2,250, 3,250, and 4,250 m). Least squares regression was used to predict CP and W' at altitude. A high-intensity intermittent test (HIIT) was performed at 250 and 2,250 m. Actual and predicted CP and W' were used to compute W' during HIIT using differential ([Formula: see text]) and integral ([Formula: see text]) forms of the [Formula: see text] model...
2017: Frontiers in Physiology
https://www.readbyqxmd.com/read/28367980/power-scalable-subcycle-pulses-from-laser-filaments
#14
A A Voronin, A M Zheltikov
Compression of optical pulses to ultrashort pulse widths using methods of nonlinear optics is a well-established technology of modern laser science. Extending these methods to pulses with high peak powers, which become available due to the rapid progress of laser technologies, is, however, limited by the universal physical principles. With the ratio P/Pcr of the peak power of an ultrashort laser pulse, P, to the critical power of self-focusing, Pcr, playing the role of the fundamental number-of-particles integral of motion of the nonlinear Schrödinger equation, keeping this ratio constant is a key principle for the power scaling of laser-induced filamentation...
April 3, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28332113/the-critical-power-concept-applications-to-sports-performance-with-a-focus-on-intermittent-high-intensity-exercise
#15
REVIEW
Andrew M Jones, Anni Vanhatalo
The curvilinear relationship between power output and the time for which it can be sustained is a fundamental and well-known feature of high-intensity exercise performance. This relationship 'levels off' at a 'critical power' (CP) that separates power outputs that can be sustained with stable values of, for example, muscle phosphocreatine, blood lactate, and pulmonary oxygen uptake ([Formula: see text]), from power outputs where these variables change continuously with time until their respective minimum and maximum values are reached and exercise intolerance occurs...
March 2017: Sports Medicine
https://www.readbyqxmd.com/read/28302463/critical-power-testing-or-self-selected-cycling-which-one-is-the-best-predictor-of-maximal-metabolic-steady-state
#16
Felipe Mattioni Maturana, Daniel A Keir, Kaitlin M McLay, Juan M Murias
Critical power (CP) demarcates the boundary between heavy and very heavy exercise intensity domains, and therefore, the power output (PO) that can be sustained at the maximal metabolic steady-state during constant-PO exercise (i.e., maximal lactate steady-state (MLSS)). However, the estimated CP does not always reflect a sustainable intensity of exercise, where blood lactate concentration ([La]) and oxygen uptake (V˙O2) reach a plateau. OBJECTIVES: To test cyclists' ability to predict their highest PO associated with metabolic steady-state based on their own perception of effort...
January 24, 2017: Journal of Science and Medicine in Sport
https://www.readbyqxmd.com/read/28280973/determinants-of-curvature-constant-w-of-the-power-duration-relationship-under-normoxia-and-hypoxia-the-effect-of-pre-exercise-alkalosis
#17
RANDOMIZED CONTROLLED TRIAL
Sanjoy K Deb, Lewis A Gough, S Andy Sparks, Lars R McNaughton
PURPOSE: This study investigated the effect of induced alkalosis on the curvature constant (W') of the power-duration relationship under normoxic and hypoxic conditions. METHODS: Eleven trained cyclists (mean ± SD) Age: 32 ± 7.2 years; body mass (bm): 77.0 ± 9.2 kg; VO2peak: 59.2 ± 6.8 ml·kg(-1)·min(-1) completed seven laboratory visits which involved the determination of individual time to peak alkalosis following sodium bicarbonate (NaHCO3) ingestion, an environment specific ramp test (e...
May 2017: European Journal of Applied Physiology
https://www.readbyqxmd.com/read/28166117/the-respiratory-compensation-point-is-not-a-valid-surrogate-for-critical-power
#18
Jeffrey A Leo, Surendran Sabapathy, Michael J Simmonds, Troy J Cross
PURPOSE: It is unclear whether the respiratory compensation point (RCP) may be used as a valid surrogate for critical power (CP). Accordingly, we sought to determine the measurement agreement between the CP and the RCP obtained during incremental cycling of varying ramp slopes. METHODS: Eleven recreationally active men completed three separate ramp-incremental cycling protocols, where the work rate increment was slow (SR, 15 W·min), medium (MR, 30 W·min), or fast (FR, 45 W·min)...
July 2017: Medicine and Science in Sports and Exercise
https://www.readbyqxmd.com/read/28019724/a-comparison-of-methods-to-estimate-anaerobic-capacity-accumulated-oxygen-deficit-and-w-during-constant-and-all-out-work-rate-profiles
#19
Daniel Muniz-Pumares, Charles Pedlar, Richard Godfrey, Mark Glaister
This study investigated (i) whether the accumulated oxygen deficit (AOD) and curvature constant of the power-duration relationship (W') are different during constant work-rate to exhaustion (CWR) and 3-min all-out (3MT) tests and (ii) the relationship between AOD and W' during CWR and 3MT. Twenty-one male cyclists (age: 40 ± 6 years; maximal oxygen uptake [V̇O2max]: 58 ± 7 ml · kg(-1) · min(-1)) completed preliminary tests to determine the V̇O2-power output relationship and V̇O2max. Subsequently, AOD and W' were determined as the difference between oxygen demand and oxygen uptake and work completed above critical power, respectively, in CWR and 3MT...
December 26, 2016: Journal of Sports Sciences
https://www.readbyqxmd.com/read/28008101/muscle-metabolic-and-neuromuscular-determinants-of-fatigue-during-cycling-in-different-exercise-intensity-domains
#20
Matthew I Black, Andrew M Jones, Jamie R Blackwell, Stephen J Bailey, Lee J Wylie, Sinead T J McDonagh, Christopher Thompson, James Kelly, Paul Sumners, Katya N Mileva, Joanna L Bowtell, Anni Vanhatalo
Lactate or gas exchange threshold (GET) and critical power (CP) are closely associated with human exercise performance. We tested the hypothesis that the limit of tolerance (Tlim) during cycle exercise performed within the exercise intensity domains demarcated by GET and CP is linked to discrete muscle metabolic and neuromuscular responses. Eleven men performed a ramp incremental exercise test, 4-5 severe-intensity (SEV; >CP) constant-work-rate (CWR) tests until Tlim, a heavy-intensity (HVY; <CP but >GET) CWR test until Tlim, and a moderate-intensity (MOD; <GET) CWR test until Tlim Muscle biopsies revealed that a similar (P > 0...
March 1, 2017: Journal of Applied Physiology
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