Biomedical subjects

George A Koumantakis

Publications and source records attributed to George A Koumantakis.

4 recordsLinked to original sources

PubMed2005

Supplementation of general endurance exercise with stabilisation training versus general exercise only. Physiological and functional outcomes of a randomised controlled trial of patients with recurrent low back pain.

BACKGROUND: Determination of the mode of action of new exercise techniques in different back pain populations is lacking. The effectiveness of supplementing an exercise programme with stabilisation exercises concerning physiological and functional parameters in non-specific back pain patients is unknown. METHODS: Randomised controlled trial, comparing a general trunk muscle endurance exercise approach enhanced with specific muscle stabilisation exercises (S&G group) with a general exercise approach only (G group). 55 patients with recurrent back pain were randomised in S&G group (n=29) and G group (n=26). Both groups received an 8-week exercise intervention and written advice. Paraspinal muscle strength and electromyographic fatigue of the erector spinae and multifidus were measured. Additionally, 3 functional speed tests were assessed. Outcomes were collected pre- and post-intervention. FINDINGS: No differences were detected for any of the paraspinal fatigue characteristics either within or between groups, apart from a significant decrease in normalised median frequency slope of the erector spinae for the G group. Paraspinal muscle strength and all functional tests have demonstrated significant within-group improvements for both groups, without any between-group differences. INTERPRETATION: An 8-week stabilisation exercise-enhanced approach presented equal benefits to a general endurance-based exercise programme for patients with recurrent non-specific back pain. A slightly steeper slope for the erector spinae in the G group was the only electromyographic fatigue alteration noted. Concomitant strength improvement probably reflects neural input changes rather than histochemical muscle changes. Physical exercise alone and not the exercise type was the key determinant for improvement in this patient group.

Back↗

PubMed2005

Trunk muscle stabilization training plus general exercise versus general exercise only: randomized controlled trial of patients with recurrent low back pain.

BACKGROUND AND PURPOSE: The purpose of this randomized controlled trial was to examine the usefulness of the addition of specific stabilization exercises to a general back and abdominal muscle exercise approach for patients with subacute or chronic nonspecific back pain by comparing a specific muscle stabilization-enhanced general exercise approach with a general exercise-only approach. SUBJECTS: Fifty-five patients with recurrent, nonspecific back pain (stabilization-enhanced exercise group: n=29, general exercise-only group: n=26) and no clinical signs suggesting spinal instability were recruited. METHODS: Both groups received an 8-week exercise intervention and written advice (The Back Book). Outcome was based on self-reported pain (Short-Form McGill Pain Questionnaire), disability (Roland-Morris Disability Questionnaire), and cognitive status (Pain Self-Efficacy Questionnaire, Tampa Scale of Kinesiophobia, Pain Locus of Control Scale) measured immediately before and after intervention and 3 months after the end of the intervention period. RESULTS: Outcome measures for both groups improved. Furthermore, self-reported disability improved more in the general exercise-only group immediately after intervention but not at the 3-month follow-up. There were generally no differences between the 2 exercise approaches for any of the other outcomes. DISCUSSION AND CONCLUSION: A general exercise program reduced disability in the short term to a greater extent than a stabilization-enhanced exercise approach in patients with recurrent nonspecific low back pain. Stabilization exercises do not appear to provide additional benefit to patients with subacute or chronic low back pain who have no clinical signs suggesting the presence of spinal instability.

Abdominal Muscles↗

PubMed2002

Between-days reliability of electromyographic measures of paraspinal muscle fatigue at 40, 50 and 60% levels of maximal voluntary contractile force.

OBJECTIVE: To ascertain which percentage of maximal voluntary contractile force of the paraspinal muscles, when tested in a functional position, is most reliable for assessing electromyographic (EMG) fatigue changes. SUBJECTS: Ten healthy volunteers with no history of low back pain (six males). MAIN OUTCOME MEASURES: The surface EMG signal during 60-second isometric contractions of the paraspinal muscles at 40, 50 and 60% levels of maximal voluntary contractile force was captured and analysed. Each contraction level was assessed on two occasions, at least three days apart. The initial median frequency, the decline in median frequency slope and the increase in root mean square values were assessed for between-days reliability, using intraclass correlation coefficients (ICCs) and standard errors of measurements (SEM). Normalized median frequency and root mean square values were also assessed. RESULTS: At 40% of maximal voluntary contraction, little or no EMG fatigue changes occurred in any of the observed parameters. At 50% maximal voluntary contraction the initial mean frequency and root mean square changes proved highly reliable, with ICCs ranging from 0.74 to 0.86 and 0.75 to 1.00 respectively. Normalizing the root mean square data reduced the reliability, but this was still acceptable with ICCs 0.70-0.83. The median frequency decline slope proved less reliable with ICCs 0.24-0.74 for raw and 0.26-0.77 for normalized data. At 60% maximal voluntary contraction the initial mean frequency proved as reliable as initial median frequency at 50% with ICCs 0.70-0.89. The raw and normalized root mean squares (ICCs 0.43-0.89 and 0.30-0.87 respectively) and raw and normalized median frequency (ICCs 0.27-0.51 and 0.24-0.53 respectively) changes were less reliable than at 50% MVC. Overall, the reliability is better at the L4/5 than at the L2/3 level. CONCLUSION: Outcome measures taken at 50% maximal voluntary contraction are the most reliable in functional testing the paraspinal muscles of healthy volunteers. With initial median frequency and root mean square values being more reliable parameters than median frequency decline. At the L4/5 level, however, all parameters were acceptably reliable at 50% of maximum effort. However the between-subject variability of the median frequency decline and root mean square incline slopes suggest that these parameters are not yet fully suitable for monitoring fatigue changes during prolonged isometric contraction.

Adult↗

PubMed2002

Thoracolumbar proprioception in individuals with and without low back pain: intratester reliability, clinical applicability, and validity.

STUDY DESIGN: Repeated measures design of active spinal position sense in individuals with and without low back pain (LBP). OBJECTIVES: Reproducibility and validity evaluation of thoracolumbar proprioception measurement. BACKGROUND: Proprioception studies in peripheral joints and the spine suggest that there may be proprioception deficits due to injury, pain, or degeneration. Kinesthetic retraining may be useful in rehabilitation of patients with LBP, but appropriate measures are required to objectively quantify spinal proprioception. METHODS AND MEASURES: Active-target reproduction in the sagittal, horizontal, and coronal planes was assessed (3 separate occasions for 18 asymptomatic volunteers and 2 occasions for 62 patients with LBP). Repositioning accuracy was expressed as absolute errors (AE) and variable errors (VE). Reliability was analyzed with intraclass correlation coefficient (ICC) and precision with standard error of measurement (SEM) and calculation of the smallest detectable difference (SDD) index. Repeated measures ANOVA and correlations were used for within-group comparisons and discriminant analysis for between-group comparisons. RESULTS: Reproducibility was better for the asymptomatic group, with AE for flexion and rotation being the most reliable (ICC = 0.76-0.80, SEM = 0.91 degrees-1.34 degrees). SDDs were high for all tests, suggesting limited clinical applicability. Reproducibility for the same tests was poor-moderate (ICC = 0.31-0.64, SEM = 0.45 degrees-3.90 degrees) for the patient group. AE for right-side rotation could discriminate between subject groups with 83.3% specificity but only 54.8% sensitivity. CONCLUSIONS: Proprioception testing, with the methods employed, did not demonstrate good measurement properties in a sample of patients with recurrent LBP. Neither could it sufficiently discriminate between individuals with and without LBP. Possible reasons for these findings are discussed.

Adult↗