Katie Bouche

Trunk muscle activity in healthy subjects during bridging stabilization exercises

BackgroundTrunk bridging exercises are often used as therapeutic exercises for lumbopelvic stabilization. These exercises focus on the retraining of muscle coordination patterns in which optimal ratios between local segmental stabilizing and global torque producing muscle activity are assumed to be essential. However, a description of such ratios is lacking. The purpose of this study was to investigate both relative (as a percentage of maximal voluntary isometric contraction) muscle activity levels and ratios of local to global muscle activity, during bridging stabilization exercises.MethodsThirty healthy university students (15 men, 15 women) with a mean age of 19.6 year volunteered to perform 3 bridging exercises (single bridging, ball bridge and unilateral bridging). The surface electromyographic activity of different trunk muscles was evaluated on both sides.ResultsDuring all bridging exercises, the ratio of the internal oblique to the rectus abdominis was very high due to minimal relative activity of the rectus abdominis. In general, the ratio of the internal/external abdominal oblique activity was about 1. However, during the unilateral bridging exercise, the ipsilateral internal/external abdominal oblique activity ratio was 2.79 as a consequence of the significant higher relative activity of the internal oblique compared to the external oblique. The relative muscle activity and the ratios of the back muscles demonstrated similar activity levels for all back muscles, resulting in ratios about 1.ConclusionBoth the minimal relative activity of the rectus abdominis and the high internal oblique to the rectus abdominis activity ratio reported in the present study are in accordance with results of other trunk stabilization exercises. The relative muscle activity and the ratio of the abdominal obliques seem to alter depending on the task and the presumable need for stability. The findings concerning the relative muscle activity and the ratios of the back muscles support the assumption that during these bridging exercises, all back muscles contribute in a similar way to control spine positions and movements in a healthy population.

Computed tomographic analysis of the quality of trunk muscles in asymptomatic and symptomatic lumbar discectomy patients

BackgroundNo consensus exists on how rehabilitation programs for lumbar discectomy patients with persistent complaints after surgery should be composed. A better understanding of normal and abnormal postoperative trunk muscle condition might help direct the treatment goals.MethodsA three-dimensional CT scan of the lumbar spine was obtained in 18 symptomatic and 18 asymptomatic patients who had undergone a lumbar discectomy 42 months to 83 months (median 63 months) previously. The psoas muscle (PS), the paraspinal muscle mass (PA) and the multifidus muscle (MF) were outlined at the L3, L4 and L5 level. Of these muscles, fat free Cross Sectional Area (CSA) and fat CSA were determined. CSA of the lumbar erector spinae (LES = longissimus thoracis + iliocostalis lumborum) was calculated by subtracting MF CSA from PA CSA. Mean muscle CSA of the left and right sides was calculated at each level. To normalize the data for interpersonal comparison, the mean CSA was divided by the CSA of the L3 vertebral body (mCSA = normalized fat-free muscle CSA; fCSA = normalized fat CSA). Differences in CSA between the pain group and the pain free group were examined using a General Linear Model (GLM). Three levels were examined to investigate the possible role of the level of operation.ResultsIn lumbar discectomy patients with pain, the mCSA of the MF was significantly smaller than in pain-free subjects (p = 0.009) independently of the level. The mCSA of the LES was significantly smaller in pain patients, but only on the L3 slice (p = 0.018). No significant difference in mCSA of the PS was found between pain patients and pain-free patients (p = 0.462). The fCSA of the MF (p = 0.186) and of the LES (p = 0.256) were not significantly different between both populations. However, the fCSA of the PS was significantly larger in pain patients than in pain-free patients. (p = 0.012).The level of operation was never a significant factor.ConclusionsCT comparison of MF, LES and PS muscle condition between lumbar discectomy patients without pain and patients with protracted postoperative pain showed a smaller fat-free muscle CSA of the MF at all levels examined, a smaller fat- free muscle CSA of the LES at the L3 level, and more fat in the PS in patients with pain. The level of operation was not found to be of importance. The present results suggest a general lumbar muscle dysfunction in the pain group, in particular of the deep stabilizing muscle system.

Reliability of a functional clinical test battery evaluating postural control, proprioception and trunk muscle activity

Stevens VK, Bouche KG, Mahieu NN, Cambier DC, Vanderstraeten GG, Danneels LA: Reliability of a functional clinical test battery evaluating postural control, proprioception and trunk muscle activity. Am J Phys Med Rehabil 2006;85:727–736. Objective:The purpose of this study was to examine the repeatability and reproducibility of the different tests of a clinical test battery evaluating the components of functional spinal stability: postural control (sway velocity data), proprioception (repositioning error), and muscle activation (electromyographic data). Design:A total of 28 healthy volunteers participated in this study: 14 in the repeatability study and 14 in the reproducibility study. Each subject was tested three times, with an interval of 1 wk between the test sessions. The intraclass correlation coefficients and the standard error of the measurements as a percentage of the grand mean were calculated. Results:The intraclass correlation coefficients for both the repeatability and the reproducibility evaluation showed good to excellent reliability for all variables (intraclass correlation coefficient, 0.60–0.98). The standard error of the measurements as a percentage of the grand mean ranged from 0.004 to 19.94. Conclusions:The functional clinical test battery investigated in this study proved to be a reliable tool in the assessment of healthy subjects. The evaluation of postural control, proprioception, and muscle activity (coordination, stabilization, maximal voluntary isometric contraction, endurance, and flexion–relaxation) showed good to excellent repeatability and reproducibility. Further analysis of the reliability of these variables in a clinical setting, particularly in patients with low back pain, seems appropriate.

A stereotaxic atlas of the forebrain of the bank vole (Clethrionomys glareolus)

In this article part of the forebrain of the bank vole (Clethrionomys glareolus) is presented in stereotaxic coordinates. The stereotaxic procedure was performed as follows. With the voles head mounted in a stereotaxic adaptor, internal reference tracks were made with a 0.5-mm diameter microdialysis cannula and India ink, 2 mm in front and 2.6 mm behind the skull landmark bregma. Brains were fixed for 72 h in 4% commercial formaldehyde in sodiumcacodylate buffer containing 1% CaCl2. To determine shrinkage they were weighed before and after fixation. After embedding in paraffin they were sectioned at 25 microm and stained with Nissl. Photomicrographs were taken from the brain of one animal while its frontal (antero-posterior) coordinates of five neural structures were compared with those of 12 other voles. Variability was also checked in lateral and vertical directions at frontal level -1.0 mm (relative to bregma). The results show that the distance between the two skull landmarks bregma and lambda correlates significantly and negatively with the antero-posterior position of each of the brain areas. On the basis of these results an equation is proposed to improve accuracy in locating neural structures that deviate due to biological variability.