Cyclic pneumatic soft-tissue compression accelerates the union of distal radial osteomoties in an ovine model

The aim of this randomised, controlled in vivo study in an ovine model was to investigate the effect of cylic pneumatic pressure on fracture healing. We performed a transverse osteotomy of the right radius in 37 sheep. They were randomised to a control group or a treatment group where they received cyclic loading of the osteotomy by the application of a pressure cuff around the muscles of the proximal forelimb. Sheep from both groups were killed at four or six weeks. Radiography, ultrasonography, biomechanical testing and histomorphometry were used to assess the differences between the groups. The area of periosteal callus, peak torsional strength, fracture stiffness, energy absorbed over the first 10° of torsion and histomorphometric analysis all showed that the osteotomies treated with the cyclic pneumatic pressure at four weeks were not significantly different from the control osteotomies at six weeks.

Illusory changes in head position induced by neck muscle vibration can alter the perception of elbow position

Acuity for elbow joint position sense (JPS) is reduced when head position is modified. Movement of the head is associated with biomechanical changes in the neck and shoulder musculoskeletal system, which may explain changes in elbow JPS. The present study aimed to determine whether elbow JPS is also influenced by illusory changes in head position. Simultaneous vibration of sternocleidomastoid (SCM) and the contralateral splenius was applied to 14 healthy adult human subjects. Muscle vibration or passive head rotation was introduced between presentation and reproduction of a target elbow position. Ten out of 14 subjects reported illusions consistent with lengthening of the vibrated muscles. In these 10 subjects, absolute error for elbow JPS increased with left SCM/right splenius vibration but not with right SCM/left splenius vibration. Absolute error also increased with right rotation, with a trend for increased error with left rotation. These results demonstrated that both actual and illusory changes in head position are associated with diminished acuity for elbow JPS, suggesting that the influence of head position on upper limb JPS depends, at least partially, on perceived head position.

Postural activity of the pelvic floor muscles is delayed during rapid arm movements in women with stress urinary incontinence

The aim of this study was to determine whether postural activity of the pelvic floor (PF) and abdominal muscles differs between continent and incontinent women during rapid arm movements that present a postural challenge to the trunk. A further aim was to study the effect of bladder filling. Electromyographic activity (EMG) of the PF, abdominal, erector spinae (ES), and deltoid muscles was recorded with surface electrodes. During rapid shoulder flexion and extension, PF EMG increased before that of the deltoid in continent women, but after the deltoid in incontinent women (p= 0.002). In many incontinent women, PF EMG decreased before the postural activation. Although delayed, postural PF EMG amplitude was greater in women with incontinence ( p= 0.010). In both groups, PF EMG decreased and abdominal and ES EMG increased when the bladder was moderately full. These findings would be expected to have negative consequences for continence and lumbopelvic stability in women with incontinence.

Reduced variability of postural strategy prevents normalization of motor changes induced by back pain: A risk factor for chronic trouble?

Variability is fundamental to biological systems and is important in posturomotor learning and control. Pain induces a protective postural strategy, although variability is normally preserved. If variability is lost, does the normal postural strategy return when pain stops? Sixteen subjects performed arm movements during control trials, when the movement evoked back pain and then when it did not. Variability in the postural strategy of the abdominal muscles and pain-related cognitions were evaluated. Only those subjects for whom pain induced a reduction in variability of the postural strategy failed to return to a normal strategy when pain stopped. They were also characterized by their pain-related cognitions. Ongoing perception of threat to the back may exert tighter evaluative control over variability of the postural strategy.

Low back pain patients demonstrate increased hip extensor muscle activity during standardized submaximal rotation efforts

Study Design. A comparative study of trunk and hip extensor muscle recruitment patterns in 2 subject groups. Objective. To examine for changes in recruitment of the hip and back extensor muscles during low level isometric trunk rotation efforts in chronic low back pain (CLBP) subjects by comparison with matched asymptomatic control subjects. Summary of Background Data. Anatomic and biomechanical models have provided evidence that muscles attaching to the thoracolumbar fascia (TLF) are important for providing stabilization to the lumbopelvic region during trunk rotation. This has guided rehabilitation programs. The muscles that link diagonally to the posterior layer of the TLF have not previously been examined individually and compared during low-level trunk rotation efforts in CLBP patients and matched controls. Methods. Thirty CLBP patients and 30 matched controls were assessed using surface electromyography (EMG) as they performed low-level isometric rotation efforts while standing upright. Muscles studied included latissimus dorsi, erector spinae, upper and lower gluteus maximus, and biceps femoris. Subjects performed the rotation exertion with various levels of external trunk support, related to different functional tasks. Results. EMG results demonstrated that subjects with CLBP had significantly higher levels of recruitment for the lower and upper gluteus maximus (P < 0.05), hamstrings (P < 0.05), and erector spinae muscles (P < 0.05) during rotation to the left compared with the control subjects. Conclusion. This study provided evidence of increased muscle recruitment in CLBP patients when performing a standardized trunk rotation task. These results may have implications for the design of therapeutic exercise programs for CLBP patients.

Interaction of psychosocial risk factors explain increased neck problems among female office workers

This study investigated the relationship between psychosocial risk factors and (1) neck symptoms and (2) neck pain and disability as measured by the neck disability index (NDI). Female office workers employed in local private and public organizations were invited to participate, with 333 completing a questionnaire. Data were collected on various risk factors including age, negative affectivity, history of previous neck trauma, physical work environment, and task demands. Sixty-one percent of the sample reported neck symptoms lasting greater than 8 days in the last 12 months. The mean NDI of the sample was 15.5 out of 100, indicating mild neck pain and disability. In a hierarchical multivariate logistic regression, low supervisor support was the only psychosocial risk factor identified with the presence of neck symptoms. Similarly, low supervisor support was the only factor associated with the score on the NDI. These associations remained after adjustment for potential confounders of age, negative affectivity, and physical risk factors. The interaction of job demands, decision authority, and supervisor support was significantly associated with the NDI in the final model and this association increased when those with previous trauma were excluded. Interestingly, and somewhat contrary to initial expectations, as job demands increased, high decision authority had an increasing effect on the NDI when supervisor support was low. Crown copyright (c) 2006 Published by Elsevier B.V. All rights reserved.