Biomedical subjects

M Portscher

Publications and source records attributed to M Portscher.

3 recordsLinked to original sources

PubMed2000

[Reproducibility of lumbar spine kinematics in clinical gait analysis].

The objective measurement of functional lumbopelvical movements enables the evaluation of the quantity and quality of movements referring to functional disorders in dynamic test-situations. The goal of the present study is the determination of the reproducibility of time-continuous movement analysis of the pelvic region during walking and the determination of possible errors. The movements of the thoracic (Th12), lumbar and sacrum-region (S1) of 17 healthy subjects (age: 32.1 +/- 2.3 years) during walking on a treadmill (4.5 km/h) were investigated twice in an interval of 24 hours by means of a 3D ultrasonic movement analysis system. The ensemble averages of the low-pass filtered and time-normalized angle-time sequences of all anatomical planes and regions showed high test-retest correlations (r > or = 0.92, p < 0.01) except fo the lumbar movement in the sagittal plane (r = 0.79, p < 0.01). A paired t-test showed no significant differences for the amplitudes of test and retest measurements except for the thoracolumbar movement in the sagittal plane (p < .05). The results show that the evaluation of lumbar movement patterns can be regarded as admissible and desirable for clinical movement analysis. The data can be used as a diagnostic tool for the planning and control of therapeutic interventions.

Adult↗

PubMedDate not supplied

[Sensomotor function while wearing lumbar support ortheses].

AIM: Flexible lumbar corsets should contribute to an improved active and passive stabilisation of the lumbar spine. In the present study, the effects of flexible corsets on sensory-motor abilities have been investigated. METHODS: 24 healthy subjects (m = 10, f = 14, 26.7 years) performed angle- and force-reproduction tasks with and without wearing a flexible corset. The subjects tried to reproduce trunk flexion angles of 20 degrees und 40 degrees as well as forces of 33% and 66% of the maximum strength of the back extensor muscles. Additionally, muscular reactions were measured during destabilizing stimuli. RESULTS: No significant differences were found for the reproduction tasks. When wearing the corset, the left erector spinae muscles showed a delayed onset (+15 ms, p < 0.05), and the obliquus abdominis reached maximal activity more rapidly (-18 ms, p < 0.05). In the preinnervation phase the obliquus abdominis (-33%, p < 0.01), in the eccentric phase the erector spinae (-27%, p < 0.05) and the right obliquus abdominis (-46%, p < 0.05) and in the concentric phase the right obliquus abdominis (-35%, p < 0.01) and the rectus abdominis (-32%, p < 0.05) showed lower activities. CONCLUSION: The reduced muscle activities with destabilizing stimuli can be interpreted as the result of an improved passive stabilisation of the lumbar region by wearing a flexible corset.

Adult↗

PubMedDate not supplied

Lumbar corsets: their effect on three-dimensional kinematics of the pelvis.

Lumbar corsets have been recommended for low back pain patients as a way of stabilizing the lumbar region, facilitating flexion movements, and reducing pain. However, little is known about how these devices affect lumbar motion. To determine the degree of changes in the lumbar region, our approach was to quantify three-dimensional kinematic data of the pelvis in harness-supported treadmill walking. Twelve healthy subjects (age=32+/-11.8 years) walked on a motorized treadmill at 4.5 km/h with and without wearing a lumbar corset. Three external markers overlying the sacrum were tracked by three ultrasound microphones, determining a local coordinate system, to obtain pelvic motions in the frontal, sagittal, and transverse planes. Raw kinematic data were low-pass filtered and normalized relative to the right heel strike. Mean values for net angular displacements of the pelvis were calculated for each plane within the 5th and 95th percentile. The Student's t-test demonstrated significant differences (P<0.001) between the corset/no-corset conditions in the frontal plane. An average 40% decrease in the relative pelvis up- and downward movement occurred in the frontal plane (4.1 degrees+/-2.9 degrees vs. 7.1 degrees+/-3.3 degrees). The analysis revealed no significant differences of net angular displacements in the sagittal (2.9 degrees+/-1.4 vs. 3.4 degrees+/-1.7 degrees) and the transverse planes (4.4 degrees+/-2.6 degrees vs. 4.3 degrees+/-2.1 degrees).

Adult↗