Abstract：
:The purpose of this study was to determine the validity and evaluate the accuracy of a portable telemetric oxygen uptake analyzer (K2). Two experiments were carried out: a) using a mechanical lung, the accuracy of the K2 to measure oxygen fractions and minute ventilation following 10 and 60 min of warm-up was determined; and b) two maximal graded exercise tests (GXT) on 15 subjects, one with the K2 system and the other with a standardized breath-by-breath (BBB) system, while heart rate (HR), minute ventilation (VE), and oxygen uptake (VO2) were compared. Following 10-min warm-up prior to calibration, the K2 underestimated the true oxygen fraction as early as 5 min into the test, and this value continued to decrease throughout the 30-min test. After 60 min of warm-up prior to calibration, the K2 accurately measured the true oxygen fraction for the first 15 min; at minute 20, and on to minute 30, the K2 underestimated the oxygen fraction. Ventilation volumes were not affected by warm-up time. Minute ventilation during the K2 GXT was significantly higher than VE for the BBB test. No significant differences were found between the HRs obtained with the BBB or K2 systems. No differences in VO2 for any stage of the GXT were identified between the K2 device, BBB device or when a respiratory exchange ratio (RER) correction factor was applied to the K2 derived values. However, the RER correction factor did minimize the VO2 differences between the BBB and K2 systems. Therefore, we conclude that the K2 accurately measures VO2 during a GXT; however, its accuracy can be compromised by limitations inherent to the system.
journal_name
Med Sci Sports Exercjournal_title
Medicine and science in sports and exerciseauthors
Crandall CG,Taylor SL,Raven PBsubject
Has Abstractpub_date
1994-01-01 00:00:00pages
108-11issue
1eissn
0195-9131issn
1530-0315journal_volume
26pub_type
杂志文章abstract：:Cardiovascular responses were obtained during cycling with graded levels of lower-body positive pressure (LBPP) applied to the exercising limbs. Seven men performed four incremental work rate (25 W.min-1) exercise (IWREx) tests to their limit of tolerance while exposed to 0, 15, 30, or 45 Torr LBPP. They also performe...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/00005768-199406000-00008
更新日期：1994-06-01 00:00:00
abstract：PURPOSE:The aim of the present study was to investigate the changes occurring in leukocyte levels of reactive oxygen species (ROS) and total blood plasma antioxidant capacity (TAS) as a result of a marathon/half-marathon race. METHODS:Fourteen men participating in the Oslo Marathon 2000 and 8 women and 8 men participa...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/01.MSS.0000106168.12113.95
更新日期：2004-01-01 00:00:00
abstract：PURPOSE:This study tested the hypothesis that exercise training improves myocardial blood flow and regional myocardial contractile function in a lateral border zone located adjacent to the ischemic zone during coronary artery occlusion. METHODS:Fourteen dogs were subjected to either 12 wk of dynamic exercise training ...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1097/00005768-200104000-00008
更新日期：2001-04-01 00:00:00
abstract：PURPOSE:Objective measurement with body worn instrumentation is a preferred and increasingly common way to gather information about young people's physical activity. Measured samples have been typically small and recruited through schools. The purpose of this article was to present the descriptive epidemiology of child...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0b013e3181d58a92
更新日期：2010-09-01 00:00:00
abstract：:A group of 103 female weight lifters (WL) and 92 control (C) women answered a survey concerning eating behavior and attitudes (including the Eating Disorder Inventory) and menstrual function. The incidence of menstrual dysfunction, defined as oligomenorrhea plus amenorrhea, was significantly higher for the WL (30%) th...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：
更新日期：1991-01-01 00:00:00
abstract：PURPOSE:To determine which combination of landing protocol and analysis technique would be the most effective at detecting differences in dynamic stability between healthy subjects and subjects with functional ankle instability (FAI). METHODS:Fifty-eight subjects participated in this investigation: 29 healthy individu...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/01.mss.0000149887.84238.6c
更新日期：2005-02-01 00:00:00
abstract：PURPOSE:To investigate the use of Tritrac accelerometers to measure energy expenditure (EE) of various activities for women in the field setting, as compared with portable indirect calorimetry. METHODS:Twenty women (age 20-29) performed a choreographed routine of six activities (walking, jogging, stair climbing, walki...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1097/00005768-200210000-00020
更新日期：2002-10-01 00:00:00
abstract：INTRODUCTION:Strenuous exercise induces significant increases in cardiac biomarkers. However, it is still unclear whether this is caused by cardiomyocyte necrosis or secondary mechanisms such as ischemia, cardiac energy deficiency, increased inflammation, or renal dysfunction. METHODS:Therefore, we investigated cardia...
journal_title：Medicine and science in sports and exercise
pub_type： 临床试验,杂志文章
doi：10.1249/MSS.0b013e31821b12eb
更新日期：2011-10-01 00:00:00
abstract：:Motivation to engage in health-promoting exercise has been ascribed to global personality traits such as self-esteem or athletic self-confidence. Self-Efficacy Theory challenges this view by proposing that highly specific estimates of personal capabilities mediate adoption of new or difficult behavior patterns. We tes...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：
更新日期：1986-10-01 00:00:00
abstract：PURPOSE:The objectives of this study were 1) to examine the differences between a noninjured (C) cohort of runners (N = 70) and runners afflicted with anterior knee pain (AKP) according to selected training, anthropometric, rearfoot motion, ground reaction force, and muscular strength and endurance variables; 2) to exp...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1097/00005768-200011000-00003
更新日期：2000-11-01 00:00:00
abstract：INTRODUCTION/PURPOSE:This study investigated whether the progressive rise in heart rate (HR) and fall in stroke volume (SV) during prolonged, constant-rate, moderate-intensity exercise (cardiovascular drift, CVdrift) in a hot environment is associated with a reduction in VO(2max). METHODS:CVdrift was measured in nine ...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/01.mss.0000152731.33450.95
更新日期：2005-02-01 00:00:00
abstract：PURPOSE:The Compendium of Physical Activities was developed to enhance the comparability of results across studies using self-report physical activity (PA) and is used to quantify the energy cost of a wide variety of PA. We provide the second update of the Compendium, called the 2011 Compendium. METHODS:The 2011 Compe...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0b013e31821ece12
更新日期：2011-08-01 00:00:00
abstract：PURPOSE:The aim of this study was to test the hypothesis that intermittent hypoxic interval training improves sea level cycling performance more than equivalent training in hypoxia or normoxia. METHODS:Thirty-three well-trained cyclists and triathletes (25.9 +/- 2.7 yr, VO(2max) 66.1 +/- 6.1 mL.min(-1).kg(-1)) were di...
journal_title：Medicine and science in sports and exercise
pub_type： 临床试验,杂志文章
doi：10.1249/01.mss.0000150077.30672.88
更新日期：2005-01-01 00:00:00
abstract：PURPOSE:Exercise training reduces pathological remodeling and improves cardiac function in ischemic heart failure; however, causal mechanisms underlying the cardiac benefits of exercise are poorly understood. Because opening of adenosine triphosphate (ATP)-sensitive K ⁺(KATP) channels protects the heart during myocardi...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0000000000000714
更新日期：2015-12-01 00:00:00
abstract：INTRODUCTION:Parents play a critical role in shaping children's attitudes, beliefs, and behaviors, including those around physical activity and inactivity. Our ability to identify which practices effectively promote children's physical activity and limit inactivity is limited by existing measurement instruments. This p...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0b013e31829d27de
更新日期：2013-12-01 00:00:00
abstract：PURPOSE:Physiological and perceptual measures during interval exercise are not well understood. The current study therefore examined the correspondence between RPE, HR, and blood lactate concentration ([La]) during interval cycling. METHODS:VO2peak and the 4.0 mmol x L(-1) lactate threshold were determined. In session...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/01.mss.0000180359.98241.a2
更新日期：2006-01-01 00:00:00
abstract：:The degree of parasympathetic control of resting heart rate (PC) was assessed by measurement of variation in heart period (VHP) during cardiopulmonary synchronization of respiration. Respiratory period was arbitrarily preset and standardized at 7 heart beats (3 beats inspiration, 4 beats expiration). The mathematical ...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/00005768-198508000-00008
更新日期：1985-08-01 00:00:00
abstract：PURPOSE:Greater resistance to muscle fatigue has been observed in women versus men and in older versus young individuals. As suggested mechanisms for these differences include task intensity and duty cycle, the purpose of this study was to evaluate fatigue in healthy young and older men and women during maximum-effort ...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/mss.0b013e31815bbb93
更新日期：2008-02-01 00:00:00
abstract：PURPOSE:To evaluate long-term susceptibility to subsequent serious exertional heat illness (EHI) in military recruits who suffered exertional heat illness during basic training. METHODS:We identified Marine Corps members who completed at least 6 months of military service and suffered EHI treated as outpatients (N = 8...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1097/00005768-200109000-00004
更新日期：2001-09-01 00:00:00
abstract：PURPOSE:The purpose of this paper was to determine whether differences in hemoglobin (Hb) and muscle aerobic capacity exist between African-American (AA) and Caucasian (CA) premenopausal women and to determine whether Hb and aerobic capacity of the muscle are associated with the racial differences in maximum oxygen upt...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1097/00005768-200110000-00019
更新日期：2001-10-01 00:00:00
abstract：:Twelve male swimmers were studied psychologically before, during, and after 10 d of increased training. Daily training distance was increased from 4,000 to 9,000 m.d-1, and intensity was maintained at 94% of VO2max. Three of the swimmers were unable to tolerate the increased training load, and they did the same distan...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/00005768-198808000-00014
更新日期：1988-08-01 00:00:00
abstract：PURPOSE:The purpose of the study was to investigate the core temperature responses to the induction of electrical exercise and to clarify whether an increase in temperature could be responsible for some of the observed reactions to acute and repeated exposure to electrical muscle stimulation. METHODS:The paralyzed thi...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1097/00005768-200103000-00015
更新日期：2001-03-01 00:00:00
abstract：PURPOSE:The purpose of this study was to investigate the effect of acute ingestion of modafinil (M) on time to exhaustion during high-intensity exercise. Modafinil (M) is a psychostimulant developed to treat narcolepsy, with "arousal" properties attributed to an increased release of dopamine in the CNS. Because other s...
journal_title：Medicine and science in sports and exercise
pub_type： 临床试验,杂志文章
doi：10.1249/01.mss.0000128146.12004.4f
更新日期：2004-06-01 00:00:00
abstract：PURPOSE:We investigated the development and recovery of peripheral and central fatigue during repeated cycling sprints and its influence on power output. METHODS:On six separate days, 12 healthy males performed the following tests: 1, 4, 6, 8, and 10 × 10 s sprints with 30 s of passive recovery between sprints, as wel...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0000000000000800
更新日期：2016-03-01 00:00:00
abstract：INTRODUCTION:Regular exercise can reduce the risk of developing cardiovascular disease through risk factor modification, with high-intensity exercise and more recently small muscle mass training providing alternatives to moderate-intensity exercise. METHODS:This study randomly assigned 53 healthy middle-age adults (ag...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章,多中心研究,随机对照试验
doi：10.1249/MSS.0000000000002053
更新日期：2019-11-01 00:00:00
abstract：:The immune response was assessed in 13 competitive bodybuilders self-administering anabolic-androgenic steroids and ten competitive bodybuilders not administering these drugs. Laboratory assessment included the number and relative distribution of T-cells, T-helper/inducer cells, T-cytotoxic/suppressor cells, activated...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章,评审
doi：
更新日期：1989-08-01 00:00:00
abstract：INTRODUCTION:Acute stress can increase fatigability and decrease steadiness of sustained low-force contractions that are required for functional tasks in upper limb muscles. Whether motor performance is more impaired in people with a chronic stress disorder is not known. PURPOSE:This study compared the fatigability an...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章,随机对照试验
doi：10.1249/MSS.0000000000000244
更新日期：2014-07-01 00:00:00
abstract：:Perceptual and physiological congruity was examined during recovery from high-intensity dynamic exercise. Nine males (24.8 +/- 0.6 yr; VO2max; 52.3 +/- 1.5 ml.kg-1.min-1) undertook in random order four maximal treadmill protocols. Treadmill speed was held constant (5.3 km.h-1) while grade was incremented by 2, 4, 6, o...
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：
更新日期：1992-03-01 00:00:00
abstract：:The extent of the growth changes in maximal work output during 10 s (MWO10), 30 s (MWO30), and 90 s (MWO90) of maximal repetitive knee flexions and extensions assessed on a modified Hydra-Gym machine was investigated in 84 boys and 83 girls, 9-19 yr of age. Body weight, fat mass and fat free mass by underwater weighin...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：
更新日期：1991-09-01 00:00:00
abstract：UNLABELLED:Limited information is currently available regarding muscle synergistic patterns and triggered reflex responses during dynamic weight-bearing activities in the presence of muscle fatigue. PURPOSE:The purpose of this study was to examine the effects of quadriceps muscle fatigue on patterns of muscle activati...
journal_title：Medicine and science in sports and exercise
pub_type： 杂志文章
doi：10.1249/MSS.0b013e3181d85527
更新日期：2010-09-01 00:00:00
