Biomedical subjects

Pierre Portero

Publications and source records attributed to Pierre Portero.

4 recordsLinked to original sources

PubMed2006

Acute neck pain: cervical spine range of motion and position sense prior to and after joint mobilization.

Despite the relatively high prevalence of cervical spine pain, the efficacy of treatment procedures is limited. In the current study, range of motion and proprioception was assessed prior to and after specific cervical spine mobilisation techniques. A 44-year-old male office worker presented with a history of cervical pain of 1 day duration. He had woken with pain, stiffness and a loss of range of motion. Examination findings indicated pain to be at C5-6 on the left side. Measurement of maximal three-dimensional cervical motion was undertaken using a Zebris system. A position matching task tested the individual's ability to actively reposition their head and neck. The treatment undertaken involved grade III down-slope mobilisations on the left side at C5-6 and C6-7 in supine lying. This technique was then progressed by placing the subject in an upright sitting position, and sustained natural apophyseal glides were performed at C6. Immediately following the treatment, the patient reported a considerable decrease in pain, less difficulty in movement and reduced stiffness. Motion analyses showed the most marked percentage improvements in range of motion after treatment were in flexion (55%), extension (35%), left rotation (56%), and left lateral flexion (22%). Ipsilateral lateral flexion with axial rotation was also notably improved following treatment. No change in proprioceptive ability was found following the treatment. The findings showed that the application of standardised specific mobilisation techniques led to substantial improvements in the range of motion and the restitution of normal coupled motion.

Adult↗

PubMed2005

Repeatability of surface EMG parameters at various isometric contraction levels and during fatigue using bipolar and Laplacian electrode configurations.

The objective of this work was to assess the repeatability of two surface electromyographic (sEMG) recording techniques, the classical bipolar configuration and a Laplacian configuration to document their ability to provide reliable information during follow-up studies. The signals were recorded on 10 healthy subjects during voluntary isometric contractions of the biceps brachii muscle at different constant contraction levels. Slopes, area ratios (at 60% of the maximal voluntary contraction (MVC)) and initial values (at 20%, 40%, 60%, 80% and 100% MVC) of the root mean square (RMS), the mean power frequency (MPF) and the muscle fibre conduction velocity (CV) were estimated. Experimental sessions were repeated on three different days with both electrode sets to evaluate the repeatability of sEMG parameter estimates. Classical results were observed, such as an increase in the RMS and the CV with the contraction level. Only initial values of RMS and MPF were shown to be dependent on electrode type. These two parameters presented intra-class correlation coefficient values higher than .80 for high contraction levels. On the whole, the repeatability of the measures was good; however it was better for all sEMG parameter estimates with bipolar electrodes than Laplacian electrodes. Because a bipolar configuration is less selective than a Laplacian one, it provides a global view of muscular activity, which is more repeatable, hence more suitable for follow-up studies.

Adult↗

PubMed2005

Exercise tolerance and daily life in McArdle's disease.

McArdle's disease is a common disorder of muscle metabolism and is due to myophosphorylase deficiency. The major complaint of patients with this disease is effort intolerance. Although the clinical features of affected patients are well known, their daily lifestyle is not well documented. The main objective of this work was to assess their mean daily energy expenditure (DEE) and compare it with control subjects. Thirty patients and 87 control subjects completed a questionnaire. A 3-day self-record of daily physical activities was used to estimate the mean DEE for patients and control subjects. A separate section of the questionnaire was used to assess patients' clinical features and daily lifestyle. The DEE of patients (44.1 +/- 6.9 kcal/kg) was not significantly different from control subjects (44.5 +/- 5.6 kcal/kg). Half of the patients with McArdle's disease performed a daily physical leisure activity as sport, sometimes at a high level (17%). Despite large individual variation, physical abilities and patients' symptoms were negatively correlated. Physical leisure activity significantly decreased the sensation of muscle pain (P < 0.03). These findings show that patients with McArdle's disease do not have a strictly sedentary lifestyle. Moreover, physical exercise appears to have positive effects on the main clinical features, such as effort intolerance. Thus, regular, moderate physical activity may be beneficial in McArdle's disease.

Activities of Daily Living↗

PubMed2004

Human muscle hardness assessment during incremental isometric contraction using transient elastography.

The aim of this study was to investigate the relationship between biceps brachii hardness using the transient elastography technique, and its activity level by quantifying the surface electromyographic signal (sEMG). Ten healthy subjects volunteered for this protocol. To assess the maximal biceps brachii myoelectric activity (sEMG-RMSm), subjects had to achieve their maximal voluntary contraction trial during an elbow flexion effort. They were then asked to perform an isometric biceps sEMG-RMS ramp trial in elbow flexion from 0% to 50% of their sEMG-RMSm in 120 s. A low-frequency pulse was sent every 5 s during all trials by an innovative shear elasticity probe previously placed over the belly of the biceps brachii allowing the calculation of a transverse shear modulus. The main results of this study were (i) the finding of a systematic linear relationship between the biceps brachii transverse shear moduli and the corresponding sEMG-RMS values. This was not the case when plotting transverse shear modulus versus the elbow flexion torque production. Therefore, the computation of a hardness index from the slope of individual transverse shear modulus-sEMG-RMS linear relationship was enabled; (ii) It was also found that the higher is the rest shear modulus, the lower is the hardness index, indicating that the transverse shear modulus change during contraction depends on its level at rest. Therefore, this non-invasive technique could be useful in the medical field to explore deep muscles which are unreachable by classical testing methods. It could also be applied for the follow-up of neuromuscular diseases inducing stiffness changes such as in Duchenne muscular dystrophy.

Adult↗