Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0015672 (fatigue)
 51,768 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purposes of this study were to develop an electrically elicited fatigue test (EEFT) that uses electrically elicited isometric muscle contractions and to examine the reliability of this test on a group of healthy individuals. Fifteen subjects were tested on two occasions, one week apart. The subjects were seated and the left leg secured to an isokinetic dynamometer with the knee positioned at 45 degrees of flexion. Maximum voluntary isometric contraction (MVIC) of the quadriceps femoris muscle was obtained and resultant knee extension torque was recorded. The quadriceps femoris muscle then was stimulated 50 times at the current level that elicited a knee extension torque level equal to 60% of that obtained during the MVIC. Percentages of decline in torque were calculated. Test-retest reliability indexes were calculated for the means of contractions 21 to 25 (r = .82, ICC = .83) and for contractions 46 to 50 (r = .92, ICC = .82). The EEFT was found to be reliable and may provide a clinically applicable means of measuring peripheral muscle fatigue.
 ...
PMID:Electrically elicited fatigue test of the quadriceps femoris muscle. Description and reliability. 358 81

The importance of accurately reproducing isokinetic strength values is critical for the assessment of training induced changes in muscle function. The purpose of this study was to determine the test re-test reliability of the Biodex System 2 Isokinetic Dynamometer for concentric quadricep and hamstring strength and muscular endurance. Twenty-one healthy volunteers underwent isokinetic testing on 2 occasions separated by 7 days. Each subject performed 5 repetitions at 60 degrees/ second followed by a muscular endurance test which consisted of 30 repetitions at 180 degrees/second. The results demonstrated high ICC values ranging from r = 0.88 to r = 0.97 and r = 0.82 to r = 0.96 for variables measured at 60 degrees/second and 180 degrees/second, respectively, SEM values were found to range from low to moderate, 4.8% to 11.6% and 5.6% to 10.8%, at 60 and 180 degrees/second, respectively. ICC coefficients were found to be low, r = 0.52 to r = 0.74, and SEM values were found to be high, 9.8% to 20.8%, for the work fatigue index at 180 degrees/second. The results demonstrate that isokinetic values obtained at 60 and 180 degrees/second are highly reproducible with the Biodex System 2 Dynamometer provided that adequate calibration, gravity correction and patient positioning is recorded and standardized. However, the work fatigue index as a measure of muscular endurance has not been shown to be reliable or precise. Changes in muscular strength over time should be considered valid if these differences lie beyond the SEM values reported in this study.
 ...
PMID:Reliability and precision of isokinetic strength and muscular endurance for the quadriceps and hamstrings. 908 Dec 67

This study investigated the psychometric properties of a battery of physical performance tests, characterized physical function in patients with cancer referred for rehabilitation, and provided normative standards against which to compare disease progression and/or future treatment effectiveness. A total of 109 patients with cancer (55 women and 54 men) and 105 control subjects (66 women and 39 men) participated. Subjects completed self-report questionnaires regarding pain, physical function, and fatigue, and also performed nine physical performance tests: the time taken to complete various tasks (picking up coins, tying a belt, reaching up, putting on a sock, standing from sitting, a 50-foot fast walk, a 50-foot walk at preferred speed), the distance walked in 6 minutes, and the distance reached forward while standing were measured. Inter-tester and test-retest reliability was good to excellent for all tests (ICC(11) 0.69 to 0.99). Known group analyses controlling for age were significant (P < 0.001) for all physical performance tests. Control subjects significantly and systematically outperformed those with cancer by a factor of two or three. Examination of the correlation matrices showed relatively low correlations between performance and external measures (r = 0.01 to 0.45). In contrast, correlations among performance measures were generally in the range of r = 0.25 to 0.85. Correlations between self-report of function and performance of functional tests were moderate, suggesting that the two methods of measuring function are complementary and both should be used for assessment and as outcome measures.
 ...
PMID:Physical function in patients with cancer: psychometric characteristics and clinical usefulness of a physical performance test battery. 1250 9

The aim of this study was to investigate the reliability of peak torque and surface electromyography (EMG) variable's root mean square (RMS) and mean frequency (MNF) during an endurance test consisting of repetitive maximum concentric knee extensions. Muscle fatigue has been quantified in several ways, and in isokinetic testing it is based on a set of repetitive contractions. To assess test-retest reliability, two sets of 100 dynamic maximum concentric knee extensions were performed using an isokinetic dynamometer. The two series were separated by 7-8 days. The subjects relaxed during the passive flexion phase. Twenty (10 men and 10 women) clinically healthy subjects volunteered. Peak torque and EMG from rectus femoris, vastus medialis, vastus lateralis and biceps femoris were recorded. RMS and MNF were calculated from the EMG signal. The reliability was calculated with intraclass correlation coefficient ICC (1.1) and standard error of measurements (SEM). The reliability of peak torque was good (ICC=0.93) and SEM showed low values. ICC was good for absolute RMS of rectus femoris (ICC>/=0.80), vastus medialis (ICC>/=0.88) and vastus lateralis (ICC>/=0.82) and MNF of rectus femoris (ICC>/=0.82) and vastus medialis (ICC>/=0.83). Peak torque, and MNF and RMS of rectus femoris and vastus medialis are reliable variables obtained from an isokinetic endurance test of the knee extensors.
 ...
PMID:Test-retest reliability of EMG and peak torque during repetitive maximum concentric knee extensions. 1270 7

The purpose of this study was to develop a test battery of hop tests with high ability to discriminate (i.e. high test-retest reliability, sensitivity, specificity and accuracy) between the hop performance of the injured and the uninjured side in patients with an ACL injury and in patients who have undergone ACL reconstruction. Five hop tests were analysed: three maximum single hop tests and two hop tests while developing fatigue. Fifteen healthy subjects performed the five hop tests on three separate occasions in a test-retest design. Thirty patients, mean 11 months after an ACL injury and 35 patients, mean 6 months after ACL reconstruction were tested. ICC values ranged from 0.85 to 0.97 for the five hop tests, indicating that all the tests had high test-retest reliability. Sixty-seven percent to 100% of the healthy subjects had normal symmetry (i.e. <10% side-to-side difference) in the five hop tests. Abnormal symmetry in the five hop tests ranged from 43 to 77% for patients with an ACL injury and from 51 to 86% for patients who had undergone ACL reconstruction respectively. The three tests with the highest ability to discriminate hop performance were chosen for the test battery; they were the vertical jump, the hop for distance and the side hop. The test battery revealed a high level of sensitivity and accuracy in patients with an ACL injury (87 and 84%) and in patients who had undergone ACL reconstruction (91 and 88%), when at least one of the three tests was classified as abnormal. To summarise, the test battery consisting of both maximum single hop performances: the vertical jump and the hop for distance and hop performance while developing fatigue: the side hop, produced high test-retest reliability, sensitivity and accuracy. Further, the test battery produced higher values compared with any of the three hop tests individually revealing that only one out of ten patients had restored hop performance 11 months after an ACL injury and 6 months after ACL reconstruction. It is concluded that this test battery showed a high ability to discriminate between the hop performance of the injured and the uninjured side both in patients with an ACL injury and in patients who have undergone ACL reconstruction.
 ...
PMID:A test battery for evaluating hop performance in patients with an ACL injury and patients who have undergone ACL reconstruction. 1652 96

Patients with knee osteoarthritis have both poor strength and endurance of their quadriceps muscles. It is possible to assess muscle fatigue by monitoring frequency spectrum using electromyography (EMG). This study used the closed kinetic chain approach to muscle assessment. Fifty-five subjects with knee osteoarthritis were examined twice within 1 week. To test maximum voluntary isometric contraction into extension an isokinetic dynamometer, with a closed kinetic chain "leg press" attachment was used. EMG assessment of signal median frequency was done by measuring median frequency shift associated with fatiguing of muscle during a 60s isometric contraction at 60% of maximum isometric contraction. Intra-class correlation coefficients with 95% confidence intervals, standard errors of measurement and smallest detectable differences were calculated. Results showed the reliability of the maximum voluntary isometric contraction extension strength test was ICC 0.99 and SEM 3.95Nm. The initial median frequency indices also demonstrated excellent ICC and SEM statistics (ICC 0.84-0.91, SEM 9.2-11Hz) for the three heads of the quadriceps; however, the fatigue slopes for all three muscles were unreliable with poor ICCs (0.04-0.72) and SDD values (2207-4000%). The assessment of peak muscle torque using a closed kinetic chain isometric technique is reliable, as is the determination of median frequency values for the quadriceps. Error for the assessment of fatigue was of an unacceptable scale. While the use of a closed kinetic chain leg press technique provides a reliable measurement of lower limb strength, EMG power spectrum decrease during an isometric contraction is of little value.
 ...
PMID:The reliability of isometric strength and fatigue measures in patients with knee osteoarthritis. 1729 24

The six-minute walk test (6-MWT) is widely used to assess functional status in patients with chronic heart failure (CHF). The aims of the present study were: (1) to compare metabolic gas exchange during the 6-MWT in older patients with left ventricular systolic dysfunction (LVSD) and in breathless patients with no major structural heart disease (MSHD); (2) to determine the exercise intensity of the 6-MWT relative to peak oxygen uptake; (3) to establish the accuracy and reproducibility of the Metamax 3B ergospirometer during an incremental workload. Twenty four older patients with LVSD (19 male; age 76 +/- 5 years; BMI 27 +/- 4), and 18 patients with no MSHD (12 male; age 75 +/- 8 years; BMI 27 +/- 4) attended on consecutive days at the same time. Patients completed a 6-MWT with metabolic gas exchange measurements using the Metamax 3B portable ergospirometer, and an incremental cycle ergometry test using both the Metamax 3B and Oxycon Pro metabolic cart. Patients returned and performed a second 6-MWT and an incremental treadmill test, metabolic gas exchange was measured with the Metamax 3B. In patients with LVSD, the 6-MWT was performed at a higher fraction of maximal exercise capacity (p = 0.02). The 6-MWT was performed below the anaerobic threshold in patients with LVSD (83 %) and in patients with no MSHD (61 %). The Metamax 3B showed satisfactory to high accuracy at 10 W and 20 W in patients with LVSD (r = 0.77 - 0.97, p < 0.05), and no MSHD (r = 0.76 - 0.94, p < 0.05). Metabolic gas exchange variables measured during the 6-MWT showed satisfactory to high day-to-day reproducibility in patients with LVSD (ICC = 0.75 - 0.98), but a higher variability was evident in participants with no MSHD (ICC = 0.62 - 0.97). The Metamax 3B portable ergospirometer is an accurate and reproducible device during submaximal, fixed rate exercise in older patients with LVSD and no MSHD. In elderly patients with LVSD and no MSHD, the 6-MWT should not be considered a maximal test of exercise capacity but rather a test of submaximal exercise performance. Our study demonstrates that the 6-MWT takes place at a higher proportion of peak oxygen uptake in patients with LVSD compared to those with no MSHD, and may be one reason why fatigue is a more prominent symptom in these patients.
 ...
PMID:Cardiorespiratory requirements of the 6-min walk test in older patients with left ventricular systolic dysfunction and no major structural heart disease. 1743 92

This study's aim was to determine the between days reliability of surface EMG recordings from the superficial quadriceps during a multi joint sub-maximal fatiguing protocol. Three subject groups (healthy n=29; patellofemoral pain syndrome n=74; knee osteoarthritis n=55) performed the task at 60 maximum voluntary isometric contraction on three separate days. Spectral and amplitude EMG parameters were recorded from vastus medialis oblique, vastus lateralis and rectus femoris and were analysed for between days reliability using intraclass correlation coefficient (ICC((2,1))), the standard errors of measure and smallest detectable differences. For frequency results, initial and final frequency values had 'good' or 'excellent' reliability in all groups for all muscles. ICCs for median frequency slopes for vastus medialis oblique, vastus lateralis, and rectus femoris respectively, in the osteoarthritis group were 0.04, 0.55, and 0.72; in the patellofemoral pain group were 0.41, 0.17, and 0.33; in the healthy group were 0.68, 0.64, and 0.31. The standard errors of measurement and smallest detectable differences for all groups and for all muscles were unacceptably high. For amplitude results, ICC root mean squared initial and final values were 'good' to 'excellent' for all groups and all muscles, albeit with high measurement error. The ICCs for root mean squared slopes in all tests were 'poor' with extremely high measurement error. The poor between days reliability and high measurement error suggests that surface EMG should not be adopted to assess fatigue during multi joint sub-maximal isometric quadriceps testing.
 ...
PMID:The reliability of surface electromyography to assess quadriceps fatigue during multi joint tasks in healthy and painful knees. 1762 11

Non-motor symptoms (NMS) in Parkinson's disease (PD) are common, significantly reduce quality of life and at present there is no validated clinical tool to assess the progress or potential response to treatment of NMS. A new 30-item scale for the assessment of NMS in PD (NMSS) was developed. NMSS contains nine dimensions: cardiovascular, sleep/fatigue, mood/cognition, perceptual problems, attention/memory, gastrointestinal, urinary, sexual function, and miscellany. The metric attributes of this instrument were analyzed. Data from 242 patients mean age 67.2 +/- 11 years, duration of disease 6.4 +/- 6 years, and 57.3% male across all stages of PD were collected from the centers in Europe, USA, and Japan. The mean NMSS score was 56.5 +/- 40.7, (range: 0-243) and only one declared no NMS. The scale provided 99.2% complete data for the analysis with the total score being free of floor and ceiling effect. Satisfactory scaling assumptions (multitrait scaling success rate >95% for all domains except miscellany) and internal consistency were reported for most of the domains (mean alpha, 0.61). Factor analysis supported the a prori nine domain structure (63% of the variance) while a small test-retest study showed satisfactory reproducibility (ICC > 0.80) for all domains except cardiovascular (ICC = 0.45). In terms of validity, the scale showed modest association with indicators of motor symptom severity and disease progression but a high correlation with other measures of NMS (NMSQuest) and health-related quality of life measure (PDQ-8) (both, rS = 0.70). In conclusion, NMSS can be used to assess the frequency and severity of NMS in PD patients across all stages in conjunction with the recently validated non-motor questionnaire.
 ...
PMID:The metric properties of a novel non-motor symptoms scale for Parkinson's disease: Results from an international pilot study. 2623 Jul 48

The objective of this study was to determine if a transcranial magnetic stimulation (TMS) method of quantifying the degree to which the motor cortex drives the muscles during voluntary efforts can be reliably applied to the human knee extensors. Although the technique for estimating "cortical" voluntary activation (VA) is valid and reliable for elbow flexors and wrist extensors, evidence that it can be applied to muscles of the lower limb is necessary if twitch interpolation with TMS is to be widely used in research or clinical practice. Eight subjects completed two identical test sessions involving brief isometric knee extensions at forces ranging from rest to maximal voluntary contraction (MVC). Electromyographic (EMG) responses to TMS of the motor cortex and electrical stimulation of the femoral nerve were recorded from the rectus femoris (RF) and biceps femoris (BF) muscles, and knee extension twitch forces evoked by stimulation were measured. The amplitude of TMS-evoked twitch forces decreased linearly between 25% and 100% MVC (r(2) > 0.9), and produced reliable estimations of resting twitch and VA (ICC(2,1) > 0.85). The reliability and size of cortical measures of VA were comparable to those derived from motor nerve stimulation when the resting twitches were estimated on the basis of as few as three TMS trials. Thus, TMS measures of VA may provide a reliable and valid tool in studies investigating central fatigue due to exercise and neurological deficits in neural drive in the lower limbs.
 ...
PMID:Cortical voluntary activation of the human knee extensors can be reliably estimated using transcranial magnetic stimulation. 1903 56


1 2 3 4 Next >>