Abstract:
PURPOSE:Isokinetic strength is normally measured for a single range of motion and body position. This study quantified the variability, between individuals, in the relationships between a single peak knee extension moment and the isokinetic extension moments measured for different hip angles and ranges of knee motion. Effects of hip angle, and of the starting knee angle of the range of motion, on isokinetic knee extension strength were also determined. METHODS:The isokinetic knee extension strength of 10 subjects was measured at 30 degrees x s(-1) to a knee flexion angle of 10 degrees from starting knee angles of 90, 75, 60, 45, and 30 degrees, in both the seated and supine positions. Moments were normalized to the peak moment from a reference contraction. RESULTS:Peak moments and moments at larger knee flexion angles were greater in the seated than in the supine position. The starting knee angle affected the peak moment, the angle of peak moment, and the moments over the initial and final portions of the range of motion. Peak moments were highly correlated between all hip angle-starting knee angle combinations. However, the normalized peak moments, the angles of peak moment, and the normalized angle-specific moments all varied considerably between subjects. The pooled standard deviation and average coefficient of variation of the normalized angle-specific moments between subjects were 10.5% of the normalizing moment and 15.7%, respectively. Excluding the reference contraction, between-subject variability was unaffected by hip angle or starting knee angle. CONCLUSIONS:Influences of hip angle, starting knee angle, and individual differences on isokinetic knee extension strength must be considered to ensure that the moments obtained from isokinetic testing adequately reflect the general strength capabilities of an individual.
journal_name
Med Sci Sports Exercjournal_title
Medicine and science in sports and exerciseauthors
Pavol MJ,Grabiner MDdoi
10.1097/00005768-200005000-00016subject
Has Abstractpub_date
2000-05-01 00:00:00pages
985-92issue
5eissn
0195-9131issn
1530-0315journal_volume
32pub_type
杂志文章abstract:PURPOSE:This study examined the direct, moderating, and indirect effects of dispositional optimism on the prediction of, and athletes' responses to, injury. METHODS:A 2-yr longitudinal design was conducted with a baseline sample of 694 asymptomatic participants (389 men, 305 women; mean ± SD age = 19.17 ± 1.69 yr), 10...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0b013e31826ea8e3
更新日期:2013-02-01 00:00:00
abstract:PURPOSE:The purpose of this study was to compare architectural characteristics of leg muscles of sprinters and distance runners. METHODS:Skeletal muscle architectural characteristics were studied in 23 elite male 100-m sprinters (SPR, 10.0-10.9 s for 100 m), 24 elite male distance runners (DR, 13.5-14.5 min for 5000 m...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-200006000-00014
更新日期:2000-06-01 00:00:00
abstract:PURPOSE:To determine the effects of age, gender, and ethnicity on the predicted aerobic power of youth as they age from 8 to 16 yr. METHODS:The sample was a multicohort group of 2540 African Americans (N = 543) and Caucasians (N = 1997), 1279 (50.4%) girls and 1261 (49.6%) boys. Heights, weights, and sum of skin folds...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-200201000-00022
更新日期:2002-01-01 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::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:PURPOSE:During and following exercise there are a number of changes in pulmonary function, among which is a decrease in forced vital capacity (FVC). Several potential mechanisms may explain this decreased FVC, including an exercise-induced increase in thoracic blood volume. METHODS:We tested the hypothesis that altere...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-199807000-00003
更新日期:1998-07-01 00:00:00
abstract:INTRODUCTION:Increased sedentary behavior predicts greater cardiovascular morbidity and mortality and does so independently of physical activity (PA). This association is only partially explained by body mass index (BMI) and overall body fat, suggesting mechanisms besides general increased adiposity. The purpose of thi...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0b013e3182a77220
更新日期:2014-03-01 00:00:00
abstract::The ventilatory stimulating effects of hypoxia occurring at carotid bodies are potentiated by exercise. However, hypoxia also has central ventilatory depressive effects; the potential interactions between this hypoxic depression and exercise have not been studied. We examined the ventilatory response to a 20 min perio...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:
更新日期:1991-06-01 00:00:00
abstract:PURPOSE:This study aimed to investigate atrophy in the deep abdominal muscles, spinal extensors, and the effect of high-load resistive exercise with and without whole-body vibration after 60 d of strict bed rest. METHODS:Twenty-four subjects underwent 60 d of head-down tilt bed rest and performed either resistive vibr...
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.0000000000001096
更新日期:2017-02-01 00:00:00
abstract:PURPOSE:High internal stress is considered to be a possible cause of heel-pad problems. External biomechanical measurements are used to attempt to understand the causes of heel pain. However, internal stress cannot be measured experimentally. Therefore, the purpose of this study was to quantify the relationship between...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:
更新日期:2005-06-01 00:00:00
abstract:PURPOSE:The effects of chronic eccentric-only versus concentric-only exercise on muscle physiology and blood biochemistry were investigated. METHODS:Twenty women performed on an isokinetic dynamometer a concentric (n = 10;mean ± SEM: age = 21.0 ± 0.4 yr, body fat = 22.0% ± 0.9%) or an eccentric (n = 10, age = 20.0 ± 0...
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.0b013e3181e91d90
更新日期:2011-01-01 00:00:00
abstract::We suggest a mechanism by which blood volume changes might explain the hypotension that, after space flight, often accompanies the return to normal gravity. Upon entering microgravity, peripheral veins may collapse and, because of volume redistribution, raise the pressure in the central venous compartment. After some ...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-199610000-00029
更新日期:1996-10-01 00:00:00
abstract:PURPOSE:Reducing ice friction was one of the motives for developing the klapskate. However, the magnitude of power dissipation that occurs with conventional skates when a skater plantar flexes his ankle and the tip of the blade is pressed into the ice has not been quantified previously. In this study, we examine how ic...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-200103000-00025
更新日期:2001-03-01 00:00:00
abstract:PURPOSE:The study's purpose was to relate body mass index (BMI) to body fat percentage as measured by dual-energy x-ray absorptiometry in female elite athletes from different sports and nonathletic controls and to investigate what characterizes the athletes with unhealthy low and high body fat values. METHODS:This stu...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0b013e31823fe4ef
更新日期:2012-05-01 00:00:00
abstract:PURPOSE:We examined the effect of electric fan use on cardiovascular and thermoregulatory responses of nine young (26 ± 3 yr) and nine aged (68 ± 4 yr) adults exposed to extreme heat and humidity. METHODS:While resting at a temperature of 42°C, relative humidity increased from 30% to 70% in 2% increments every 5 min. ...
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.0000000000001348
更新日期:2017-11-01 00:00:00
abstract::Since many physiological, metabolic, and endocrine changes that occur during pregnancy are evident even at rest, the alterations found during exercise may not necessarily be the same as those found in the normal population. Nonetheless, the exercise-induced cardiopulmonary changes are essentially normal or slightly ex...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章,评审
doi:10.1249/00005768-198508000-00001
更新日期:1985-08-01 00:00:00
abstract:PURPOSE:The purpose of this study was to examine and quantify the effect of repeated driving stints on the physiologic, metabolic, and hormonal responses of three professional endurance driver-athletes. METHODS:Core body temperature, HR, and physiological strain index were recorded during the Rolex 24 Hours of Daytona...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000002507
更新日期:2020-09-01 00:00:00
abstract::Sprint-trained athletes demonstrate a remarkable ability to perform exercise which results in fatigue quickly. However, the mechanisms for these enhanced performance capabilities have not been fully elucidated. Elevation in glycolytic enzymes and increased fast-twitch fiber compositions which would result in an enhanc...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章,评审
doi:
更新日期:1984-08-01 00:00:00
abstract:PURPOSE:Physical activity (PA) associates with cardiovascular autonomic function, but the relationship with lifelong PA is unclear. We hypothesized that lifelong PA would associate with cardiovascular autonomic function in midlife. METHODS:At the age of 46 yr, the subjects of the prospective Northern Finland Birth Coh...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000000942
更新日期:2016-08-01 00:00:00
abstract:PURPOSE:Studies have shown that absolute intensity of physical activity is associated with reduced risk of preeclampsia. This analysis was performed to examine whether relative intensity may also be related to preeclampsia risk. METHODS:Using data from a case-control study conducted from 1998 to 2002, the authors asse...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/01.mss.0000175862.41620.41
更新日期:2005-11-01 00:00:00
abstract:PURPOSE:To evaluate the effects of intensity of exercise on insulin resistance and the expression of inflammatory proteins in the skeletal muscle of diet-induced obese (DIO) rats after a single bout of exercise. METHODS:In the first exercise protocol, the rats swam for two 3-h bouts, separated by a 45-min rest period ...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0b013e3181e45d08
更新日期:2010-12-01 00:00:00
abstract:PURPOSE:We examined bilateral bone mineral density (BMD) in the arms of female college gymnasts to assess the relative contribution of high-impact loading forces versus daily activities on bone plasticity. METHODS:Twenty-five female collegiate gymnasts and 25 controls were studied. BMD of the lumbar spine, proximal fe...
journal_title:Medicine and science in sports and exercise
pub_type: 临床试验,杂志文章
doi:10.1097/00005768-200211000-00021
更新日期:2002-11-01 00:00:00
abstract::Regression analysis is often used to demonstrate associations among variables believed to be biologically related. Failure to demonstrate a "significant" relationship may be due to two factors: 1) the variables are truly unrelated, or 2) a relationship exists but goes undetected due to inadequate statistical power. In...
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::Two swims (1993 and 1994) are described which led to post-swim orthostatic intolerance and one episode of syncope in a 50/51-yr-old well-trained and experienced marathon swimmer. The swims of 33 km and 38 km took 12 h 30 s and 17 h 35 min, respectively. Water temperature in each swim was above 23 degrees C and rectal ...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:
更新日期:1995-09-01 00:00:00
abstract:PURPOSE:To compare the physiological and performance adaptations between periodized and nonperiodized resistance training in women collegiate tennis athletes. METHODS:Thirty women (19 +/- 1 yr) were assigned to either a periodized resistance training group (P), nonperiodized training group (NV), or a control group (C)...
journal_title:Medicine and science in sports and exercise
pub_type: 临床试验,杂志文章
doi:10.1097/00005768-200301000-00024
更新日期:2003-01-01 00:00:00
abstract:PURPOSE:Existing studies have failed to provide evidence of a positive effect on exercise performance by wearing compression short tights covering only both thighs. This could be due to an inadequate pressure intensity that otherwise has a significant effect if applied on the crucial point in the thigh. This study aime...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000000330
更新日期:2014-11-01 00:00:00
abstract:BACKGROUND:Skeletal muscle from lean and obese subjects elicit differential adaptations in response to exercise/muscle contractions. In order to determine whether obesity alters the adaptations in mitochondrial dynamics in response to exercise/muscle contractions and whether any of these distinct adaptations are linked...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000002580
更新日期:2020-12-11 00:00:00
abstract::Sixteen untrained males, age 46 +/- 11 yr (mean +/- SD), were studied to determine the effects of 20 wk of strength training on lipoprotein-lipid profiles and post-heparin lipase activities. All subjects had abnormal lipoprotein-lipid profiles and at least two other risk factors for coronary heart disease (CHD). To co...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:
更新日期:1991-10-01 00:00:00
abstract:PURPOSE:To describe the level of usage of protective devices and equipment in a cohort of New Zealand rugby players. METHODS:Male and female players (N = 327) from a range of competitive grades were followed over the course of the season. Participants were interviewed weekly about their participation in rugby and use ...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-200112000-00024
更新日期:2001-12-01 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