Abstract：
INTRODUCTION:Exogenous ketones potentially provide an alternative, energetically advantageous fuel to power exercising skeletal muscle. However, there is limited evidence regarding their relative contribution to energy expenditure during exercise. Furthermore, the effect of blood ketone concentration and exercise intensity on exogenous ketone oxidation rates is unknown. METHODS:Six athletes completed cycling ergometer exercise on three occasions within a single-blind, random-order controlled, crossover design study. Exercise duration was 60 min, consisting of 20-min intervals at 25%, 50%, and 75% maximal power output (WMax). Participants consumed (i) bitter flavored water (control), (ii) a low-dose β-hydroxybutyrate (βHB) ketone monoester (KME; 252 mg·kg BW-1, "low ketosis"), or (iii) a high-dose βHB KME (752 mg·kg BW-1, "high ketosis"). The KME contained a 13C isotope label, allowing for the determination of whole-body exogenous βHB oxidation rates through sampled respiratory gases. RESULTS:Despite an approximate doubling of blood βHB concentrations between low- and high-ketosis conditions (~2 mM vs ~4.4 mM), exogenous βHB oxidation rates were similar at rest and throughout exercise. The contribution of exogenous βHB oxidation to energy expenditure peaked during the 25% WMax exercise intensity but was relatively low (4.46% ± 2.71%). Delta efficiency during cycling exercise was significantly greater in the low-ketosis (25.9% ± 2.1%) versus control condition (24.1% ± 1.9%; P = 0.027). CONCLUSIONS:Regardless of exercise intensity, exogenous βHB oxidation contributes minimally to energy expenditure and is not increased by elevating circulating concentrations greater than ~2 mM. Despite low exogenous βHB oxidation rates, exercise efficiency was significantly improved when blood βHB concentration was raised to ~2 mM.
journal_name
Med Sci Sports Exercjournal_title
Medicine and science in sports and exerciseauthors
Dearlove DJ,Harrison OK,Hodson L,Jefferson A,Clarke K,Cox PJdoi
10.1249/MSS.0000000000002502subject
Has Abstractpub_date
2020-08-28 00:00:00eissn
0195-9131issn
1530-0315pub_type
杂志文章abstract：PURPOSE:The midfoot is instrumental to foot function; however, quantifying its roles in human movement has been difficult. A forceful dynamic activity like landing may help elucidate the midfoot's contribution to foot energetics and function. The main purpose of this study was to measure midtarsal joint kinematics and ...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0000000000001765
更新日期：2019-01-01 00:00:00
abstract：PURPOSE:To investigate the effects of blood flow restriction (BFR) combined with electrical muscle stimulation (EMS) on skeletal muscle mass and strength during a period of limb disuse. METHODS:Thirty healthy participants (22 ± 3 years; 23 ± 3 kg·m) were randomly assigned to either: control (CON; n=10), BFR alone (BFR...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0000000000002544
更新日期：2020-10-22 00:00:00
abstract：PURPOSE:Exercise improves the diagnostic performance of ankle-to-brachial index (ABI) in the detection of exercise-induced arterial endofibrosis (EIAE). Pressure values for all four limbs are required to calculate ABI, but rapid systemic pressure changes occur during the recovery period from exercise. We checked whethe...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/01.mss.0000232021.21361.9c
更新日期：2006-11-01 00:00:00
abstract：UNLABELLED:Clinical treatment in physical rehabilitation routinely uses perceived relative forces. PURPOSE:This study used psychophysical methods to quantify subjects' errors during submaximal muscular force production. METHODS:A sample of young adult (aged 23 +/- 3 yr) females (N = 60, 62 +/- 14 kg) and males (N = 5...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1097/00005768-200002000-00028
更新日期：2000-02-01 00:00:00
abstract：:The case of a table tennis player suffering from intra-articular loose bodies of the elbow is reported. The patient developed the first signs of osteochondritis dissecans of the right lateral humeral condyle at age 16 but underwent surgery only 6 yr later. He has now resumed training and competition, despite some resi...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：
更新日期：1991-08-01 00:00:00
abstract：:A 25-yr-old female triathlete presented with 4 d of increasing left calf pain that started 1 d after an elective termination of pregnancy during the eighth week of gestation. She had been training with running, bicycling, and swimming but did not recall any injury to the calf muscle. Deep venous thrombosis of the calf...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：
更新日期：1992-01-01 00:00:00
abstract：:Ingestion of fluids providing carbohydrate and electrolytes extends endurance times during prolonged exercise. To understand the contribution of these factors, we examined hormonal, physiologic, and metabolic responses to ingesting water (W) or a 7% glucose polymer/fructose/electrolyte solution (GPFE) in 10 men (age: ...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：
更新日期：1992-01-01 00:00:00
abstract：PURPOSE:Identify the prevalence of and traits that may increase the risk of low bone mineral density (BMD) among 93 female adolescent competitive endurance runners. METHODS:Participants were 93 high school runners, ages 13-18 yr, from southern California. Eating attitudes and behaviors were assessed using the Eating D...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0b013e3181822ea0
更新日期：2008-12-01 00:00:00
abstract：:Energy expenditure during bicycling on flat terrain depends predominantly on air resistance, which is a function of total frontal area (bicycle and rider), coefficient of drag, and air speed. Body position on the bicycle may affect energy expenditure by altering either frontal area or coefficient of drag. In this stud...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：
更新日期：1991-08-01 00:00:00
abstract：PURPOSE:The frequency of interruptions in sedentary time (sedentary breaks) is an aspect of sedentary behaviors that may be associated with metabolic health outcomes. The aim of this study was to describe the change in the frequency of sedentary breaks during a 10-yr period from ages 5 to 15 yr. METHODS:The longitudin...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0b013e318245ca20
更新日期：2012-06-01 00:00:00
abstract：PURPOSE:Physical activity (PA) promotion among youth is a public health priority, and there is a need for robust surveillance systems to help support such initiatives. Existing youth PA self-report instruments that are used for surveillance lack information regarding the types and contexts of activity. Further, these i...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0000000000001562
更新日期：2018-06-01 00:00:00
abstract：:To examine the hypothesis that the skin blood flow response to body heating is not uniform over the entire body surface, we compared forearm (FBF) and calf (CBF) blood flow responses to an increase in core temperature (esophageal temperature, Tes) during dynamic exercise. We studied 13 physically active men during sem...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：
更新日期：1992-02-01 00:00:00
abstract：PURPOSE:This study investigated whether natural killer (NK) cells and CD8+ T cells expressing cutaneous lymphocyte antigen (CLA)-a homing molecule for endothelial cell leukocyte adhesion molecule 1, which enables transmigration to the skin-are selectively mobilized in response to acute exercise. METHODS:Nine healthy m...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0000000000000914
更新日期：2016-07-01 00:00:00
abstract：:The effects of the potent opioid, sufentanil, were studied in 11 athletes. Sufentanil was administered intravenously (up to 0.5 microgram.kg-1 over 10 min) to the subjects while they ran at 14 km.hr-1 on a level treadmill. Prior to, and after, the drug infusion, the treadmill was inclined by 6% for 4 min and CO2 was i...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：
更新日期：1988-12-01 00:00:00
abstract：PURPOSE:The purpose of this study was to determine whether increased intraluminal pressure is the damaging factor that reduces flow-mediated dilation (FMD) in young, healthy subjects after resistance exercise to maximal exertion. HYPOTHESIS:Attenuating the rise in brachial artery pressure during weight lifting by plac...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0000000000001150
更新日期：2017-04-01 00:00:00
abstract：PURPOSE:This study determined the dose-response effects of inhaled salbutamol (SAL) on time-trial performance and urine concentrations of SAL (cSAL). METHODS:Nonasthmatic, trained male cyclists and triathletes (N = 37) were studied. Day 1 consisted of screening for airway hyperresponsiveness, using a eucapnic voluntar...
journal_title：Medicine and science in sports and exercise
pub_type： 临床试验,杂志文章,随机对照试验
doi：10.1249/mss.0b013e3181591df7
更新日期：2008-01-01 00:00:00
abstract：PURPOSE:Increasing step rate has been shown to elicit changes in joint kinematics and kinetics during running, and it has been suggested as a possible rehabilitation strategy for runners with patellofemoral pain. The purpose of this study was to determine how altering step rate affects internal muscle forces and patell...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0b013e3182a78c3a
更新日期：2014-03-01 00:00:00
abstract：PURPOSE:Since the introduction of carving skis, muscle activity has been investigated primarily on expert-level skiers with respect to EMG intensities. The three-part aim of this recreational skiing study was to analyze functional differences within the quadriceps muscle, to analyze the topographical influence, and to ...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0b013e3181d299cf
更新日期：2010-08-01 00:00:00
abstract：:To investigate the effect of temperature stress on responses to static-dynamic work in patients with ischemic heart disease (IHD), 10 men with IHD shoveled gravel for 30 min in a warm (29 degrees C), neutral (24 degrees C), and cold (-8 degrees C) environment (on separate days). A pace of 15 lifts.min-1 was set, and t...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/00005768-199307000-00006
更新日期：1993-07-01 00:00:00
abstract：:The purpose of this study was to investigate the association between elite endurance athlete (EEA) status and two restriction fragment length polymorphisms (RFLPs) at the muscle-specific creatine kinase (CKMM) gene locus. Genomic DNA was extracted from white blood cells or lymphoblastoid cell lines of 124 unrelated Ca...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1097/00005768-199711000-00009
更新日期：1997-11-01 00:00:00
abstract：:Throughout a beat swinging motion prior to a kip the gymnast changes the relative orientation of his legs and head-torso with respect to his arms. It was observed that if these changes occurred in a correct order he could rapidly increase his swing with his limited strength. If changes in orientation of the body parts...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：
更新日期：1980-04-01 00:00:00
abstract：PURPOSE:High school cross-country runners have a high incidence of injury, particularly at the shin and knee. An increased step rate during running has been shown to reduce impact forces and loading of the lower extremity joints. The purpose of this prospective study was to examine step rate as a risk factor for injury...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0000000000000890
更新日期：2016-07-01 00:00:00
abstract：PURPOSE:This study examined the validity of the assumption of lower-extremity kinematic parameter reproducibility and symmetry during running with different velocities and stride frequencies. METHODS:Each of 12 female long-distance runners ran on a treadmill in combinations of three different velocities (2.5, 3.0, and...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/01.MSS.0000069337.49567.F0
更新日期：2003-06-01 00:00:00
abstract：PURPOSE:Physically active women have a reduced risk of breast cancer, but the dose of activity necessary and the role of energy balance and other potential mechanisms have not been fully explored in animal models. We examined treadmill and wheel running effects on mammary tumorigenesis and biomarkers in p53-deficient (...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0b013e31819f1f05
更新日期：2009-08-01 00:00:00
abstract：BACKGROUND:The Sedentary Sphere is a method for the analysis, identification, and visual presentation of sedentary behaviors from a wrist-worn triaxial accelerometer. PURPOSE:This study aimed to introduce the concept of the Sedentary Sphere and to determine the accuracy of posture classification from wrist acceleromet...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0000000000000224
更新日期：2014-06-01 00:00:00
abstract：:The inheritance of cardiac changes during acute dynamic physical exercise was studied in 21 pairs of monozygotic and 12 pairs of dizygotic male twins, ages 18-31 yr. Echocardiography was performed in resting conditions and at submaximal supine bicycle exercise at a heart rate of 110 bpm. In resting conditions signific...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：
更新日期：1991-11-01 00:00:00
abstract：:Studies using wearable sensors to measure posture, physical activity (PA), and sedentary behavior typically use a single sensor worn on the ankle, thigh, wrist, or hip. Although the use of single sensors may be convenient, using multiple sensors is becoming more practical as sensors miniaturize. PURPOSE:We evaluated ...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0000000000002306
更新日期：2020-08-01 00:00:00
abstract：:The effects of metabolic alkalosis on muscle lactate accumulation and plasma catecholamine concentrations were studied in six highly trained subjects during short-term ergocycle exercises to exhaustion (375 W). The studies were performed after oral administration of NaHCO3 (alkalosis) and CaCO3 (placebo). There was a ...
journal_title：Medicine and science in sports and exercise
pub_type： 临床试验,杂志文章
doi：10.1249/00005768-198806000-00003
更新日期：1988-06-01 00:00:00
abstract：INTRODUCTION:Low lean mass (LM) is a risk factor for chronic disease, a major cause of disability and diminished quality of life, and is a heritable trait. However, relatively few specific genetic factors have been identified as potentially influencing this trait. METHODS:In this study, we selected 1493 single-nucleot...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0000000000000889
更新日期：2016-07-01 00:00:00
abstract：PURPOSE:Stroke volume response to exercise depends on changes in cardiac filling, intrinsic myocardial contractility, and left ventricular afterload. The purpose of this study was to compare these responses during an upright cycle test performed until exhaustion in children and adults. METHODS:Stroke volume, cardiac o...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1097/00005768-200203000-00012
更新日期：2002-03-01 00:00:00
