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 activation and performance in response to sudden, unexpected perturbations during a weight-bearing task. METHODS:Motion of the knee was measured as subjects were asked to track a visual target as accurately as possible while performing a resisted single leg squat task. Random perturbations were delivered in 20% of the trials by unexpectedly releasing the resistance during the flexion phase of the exercise. Absolute and constant errors were calculated to evaluate target tracking performance. Quadriceps and hamstring muscle activity was recorded during both perturbed and unperturbed trials. Twelve healthy women were tested before and after completing a repetitive submaximal eccentric quadriceps fatigue protocol. A second group of 12 women served as controls. Unexpected perturbations elicited long-latency responses characterized by facilitation of the quadriceps and inhibition of the hamstrings. RESULTS:Muscle fatigue increased the amplitude of the long-latency response in vastus lateralis by 4.3% maximum voluntary isometric contraction (P = 0.004). Changes in tracking error occurred in response to perturbations after fatigue in spite of significantly increased quadriceps muscle activity, especially during the extension phase of the exercise. CONCLUSION:Quadriceps muscle fatigue alters the patterns of coordinated muscle activity and may render subjects less able to cope with unexpected perturbations during weight-bearing tasks.
journal_name
Med Sci Sports Exercjournal_title
Medicine and science in sports and exerciseauthors
Ballantyne BT,Shields RKdoi
10.1249/MSS.0b013e3181d85527subject
Has Abstractpub_date
2010-09-01 00:00:00pages
1712-22issue
9eissn
0195-9131issn
1530-0315journal_volume
42pub_type
杂志文章abstract:PURPOSE:The extent to which the diaphragm is targeted during a bout of inspiratory muscle training (IMT) is unknown. The purpose of this study was to characterize the relative activation patterns of the diaphragm and extradiaphragmatic inspiratory muscles during a bout of IMT and to determine whether diaphragmatic recr...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000000881
更新日期:2016-06-01 00:00:00
abstract:PURPOSE:To examine change in physical fitness and body composition after a military deployment to Afghanistan. METHODS:One hundred and ten infantry soldiers were measured before and after a 9-month deployment to Afghanistan for Operation Enduring Freedom. Measurements included treadmill peak oxygen uptake (peak VO2), ...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0b013e318176b978
更新日期:2008-09-01 00:00:00
abstract::Muscle fatigue has been studied with a variety approaches, tools and technologies. The foci of these studies have ranged tremendously, from molecules to the entire organism. Single cell and animal models have been used to gain mechanistic insight into the fatigue process. The theme of this review is the concept that t...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章,评审
doi:10.1249/MSS.0000000000001052
更新日期:2016-11-01 00:00:00
abstract:INTRODUCTION:Arterialization of venous gas emboli (VGE) formed after surfacing from SCUBA diving can become arterial gas emboli (AGE) through intrapulmonary arterial-venous anastomoses that open with exercise. METHODS:We recruited twenty patent foramen ovale-negative SCUBA divers and conducted a field and a laboratory...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000000625
更新日期:2015-09-01 00:00:00
abstract:PURPOSE:Resting cardiac vagal modulation (RCVM) and postexercise vagal reactivation (PEVR) are markers of parasympathetic activity. We investigated whether adaptations in these markers to aerobic training are influenced by baseline autonomic control. METHODS:Forty healthy men (19.2 ± 0.8 yr) of similar cardiorespirato...
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.0000000000000532
更新日期:2015-06-01 00:00:00
abstract:BACKGROUND:Pedometry methods for collecting data in young populations are advancing, but it is unclear how many days of data are enough for population monitoring. METHODS:Using random-digit dialing, 11,669 5- to 19-yr-olds were recruited into the Canadian Physical Activity Levels among Youth study and mailed a data co...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0b013e3181b67544
更新日期:2010-03-01 00:00:00
abstract:PURPOSE:The main purpose of the present investigation was to test whether and to what extent familial/genetic factors are involved in the changes of postheparin lipoprotein lipase (deltaPH-LPL) activity and triglyceride (deltaTG) levels in response to exercise training. Additional hypotheses were also tested as to whet...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-200008000-00012
更新日期:2000-08-01 00:00:00
abstract::To determine the relation of plasma volume change to intensity of weight lifting, blood samples were obtained from 15 males [mean (+/- SD) age = 22.3 +/- 3.2 yr; height = 176.3 +/- 6.9 cm; weight = 73.0 +/- 11.7 kg] before and over a 60-min period following weight lifting at four different intensities [40, 50, 60, and...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:
更新日期:1989-04-01 00:00:00
abstract::Vigorous exercise is associated with a sensation of well-being, and this subjective state has been objectively quantified with psychometric, cardiovascular, and neurophysiological data. Reductions in state anxiety have been demonstrated to follow acute physical activity, and this response persists for 2-5 h. Chronic p...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章,评审
doi:
更新日期:1985-02-01 00:00:00
abstract:PURPOSE:The present study was designed to develop and validate a prediction equation for peak oxygen consumption VO2peak) using a progressive treadmill test and to refine the current target HR exercise guidelines for pregnancy (PARmed-X for Pregnancy). METHODS:One hundred fifty-six women between 16 and 22 wk of gestat...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/01.mss.0000228940.09411.9c
更新日期:2006-08-01 00:00:00
abstract:PURPOSE:Strain magnitude is known to be a primary determinant of the osteogenic response to loading. However, whether bone adaptation to muscle loading is determined primarily by load magnitude is unclear. The purpose of this study was to determine the contribution of load magnitude from muscle action on the site-speci...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-199909000-00009
更新日期:1999-09-01 00:00:00
abstract:PURPOSE:This study aimed to analyze the influence of foot strike pattern on running economy and biomechanical characteristics in subelite runners with a similar performance level. METHODS:Twenty subelite long-distance runners participated and were divided into two groups according to their foot strike pattern: rearfoo...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000000139
更新日期:2014-03-01 00:00:00
abstract:PURPOSE:The present study assessed the factorial validity and gender invariance of the Social Physique Anxiety Scale (SPAS) using a sample of young adolescents. Existing SPAS 12-item, one- and two-factor and truncated, one-factor (i.e., nine-item and seven-item) measurement models reported in the adult literature were ...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/01.mss.0000117111.76228.bf
更新日期:2004-03-01 00:00:00
abstract:PURPOSE:The purpose of the current study was to investigate the associations between the GNB3 C825T polymorphism, body fatness and fitness, and blood pressure in a sample of young Korean men. METHODS:A total of 282 apparently healthy Korean men (nonobese N = 152, obese N = 130) aged 19-33 yr participated in the study....
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/01.mss.0000170096.96662.05
更新日期:2005-07-01 00:00:00
abstract:PURPOSE:High-intensity interval training (HIIT) represents a potent stimulus to the dynamic oxygen uptake (V˙O2) response in adults, but whether the same is evident in youth is unknown. HIIT has also been suggested to place a lower demand on the respiratory system, decreasing the likelihood of exacerbation in those wit...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000002270
更新日期:2020-06-01 00:00:00
abstract:OBJECTIVE:To evaluate the effect of chronic moderate-intensity exercise upon the alterations of immune system cell function induced by energy restriction. METHODS:Forty male Wistar rats were randomly assigned to the following groups: sedentary animals fed ad libitum (SF, N = 10) or submitted to energy restriction (SER...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/01.mss.0000147626.32295.38
更新日期:2004-12-01 00:00:00
abstract:INTRODUCTION/PURPOSE:To examine whether fluctuations in training load during an Olympic year lead to changes in bone mineral densities and factors that regulate bone (sclerostin, osteoprotegerin and receptor activator of nuclear factor kappa-B ligand), energy metabolism (insulin-like growth factor-1 and leptin), and in...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000001640
更新日期:2018-09-01 00:00:00
abstract::It has been widely claimed that exercise is beneficial to dysmenorrhea, yet solid evidence is lacking. Studies investigating this relationship have been reviewed for this paper. Most showed decreased prevalence and/or improved symptomatology with exercise. However, controlled longitudinal studies involving women with ...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章,评审
doi:10.1097/00005768-199806000-00020
更新日期:1998-06-01 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::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::Although low back pain (LBP) is a widespread and disabling health problem, there is a lack of evidence based medicine with respect to its treatment and rehabilitation. A major reason for this is the poor understanding of the underlying mechanisms of the LBP syndromes. In an attempt to fill this gap, the present review...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章,评审
doi:10.1097/00005768-200111000-00014
更新日期:2001-11-01 00:00:00
abstract:INTRODUCTION:The significant sex disparity in sports-related knee injuries may be due to underlying differences in motor control. Although the development of sex-specific movement patterns is likely multifactorial, this study specifically focuses on the potential modulatory role of sex hormones. PURPOSE:This study aim...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000000134
更新日期:2014-03-01 00:00:00
abstract:PURPOSE:To determine the prevalence of reversible airway obstruction in a group of professional football training camp participants. METHODS:All attendees at a Canadian Football League team rookie preseason training camp were invited to participate in a protocol designed to elicit symptoms and signs of reversible airw...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-200012000-00003
更新日期:2000-12-01 00:00:00
abstract:PURPOSE:We investigated the knee-extensor torque at which reoxygenation (inflow of arterial blood) during an isometric contraction stopped, whether this torque depended on maximal torque capacity (MTC), and whether there were differences among the synergists. METHODS:Isometric knee-extension torque was measured using ...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/mss.0b013e31802dd3cc
更新日期:2007-03-01 00:00:00
abstract:INTRODUCTION:Unilateral elbow pain results in sensorimotor dysfunction that is frequently bilateral, affects local and remote upper limb muscles, and persists beyond resolution of local tendon symptoms. These characteristics suggest supraspinal involvement. Here, we investigated 1) the excitability and organization of ...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000000469
更新日期:2015-04-01 00:00:00
abstract:INTRODUCTION:The isometric muscle force attained after active stretch is greater than that attained in a purely isometric contraction. This property is referred to as residual force enhancement (RFE). Because RFE is thought to be caused by a titin-based passive force, it should be preserved in reduced contractile force...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/MSS.0000000000001563
更新日期:2018-06-01 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:INTRODUCTION:The purpose of this study was to validate a parent proxy record of children's physical activity with CSA Model 7164 accelerometers. METHODS:A parent proxy record was developed to record children's activity after school on weekdays and all day long on weekends for 7 d. Parents recorded both duration and in...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1249/01.mss.0000174906.38722.2e
更新日期:2005-08-01 00:00:00
abstract:PURPOSE:The influence of maximal strength, as measured by the maximal load lifted for one repetition (1RM), on power production in the initial 200 ms of the concentric phase for both rebound and nonrebound movements was investigated. We also investigated the effect of external load upon this relationship. METHODS:Twen...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-200010000-00016
更新日期:2000-10-01 00:00:00
abstract:OBJECTIVE:To examine the effect of an increase in roller ski rolling resistance on the physiological and upper body demands of roller skiing with the V2-alternate technique. METHODS:Nine highly skilled cross-country skiers roller skied at three paced speeds on a flat oval loop using roller skis with high (HiR) and low...
journal_title:Medicine and science in sports and exercise
pub_type: 杂志文章
doi:10.1097/00005768-199805000-00018
更新日期:1998-05-01 00:00:00