Dianne Newham

Abdominal muscle size and symmetry in normal subjects

This study was undertaken to establish normal reference ranges for abdominal muscle size and symmetry and to examine the effects on these of gender and age. We studied 123 subjects, consisting of 55 men (aged 21–72 years) and 68 women (aged 20–64 years). Real‐time ultrasound imaging of the abdominal muscles was performed. Thickness of internal and external oblique (IO, EO), transversus abdominis (TA), and rectus abdominis (RA), and cross‐sectional area (CSA) of RA were measured, and absolute and relative muscle thickness (percent total muscle thickness), order of thickness, and symmetry (percent difference between sides) were determined. Males had significantly larger muscles than females and size was poorly correlated with age. The pattern of relative muscle thickness was RA > IO > EO > TA. Symmetry for total absolute thickness of all three lateral muscles was 8%–9% (mean) but for individual muscles there was asymmetry of absolute size (13%–24%), whereas relative thickness was symmetrical for all muscles. These findings provide robust reference data for the abdominal muscles in normal males and females in order to enable comparison with clinical groups to assess abnormalities and establish sensitivity for evaluating the effectiveness of interventions. Muscle Nerve, 2006

Muscle strength and walking ability in Diplegic Cerebral Palsy: Implications for assessment and management

Muscle weakness is a recognised problem in children with Cerebral Palsy (CP). Changes in the understanding of motor control, and progress in the treatment of spasticity, have led to a greater appreciation that spastic muscles are also weak. In recent years weakness has been identified in isolated muscle groups, but studies quantifying the degree and distribution of weakness in multiple muscles remain limited. This study evaluated isometric lower limb muscle strength in 50 ambulant children with CP/Spastic Diplegia (mean age 11 years 7 months) at GMFCS levels I (n=14), II (n=26) and III (n=10). Muscle strength was compared with 15 control children (mean age 11 years 1 month) using the same protocol. Six muscle groups in both lower limbs were measured using a digital dynamometer. All lower limb muscles were significantly weaker in the CP children than in healthy children (p<0.05) except for the hip extensors. Muscle strength ranged from 43% to 90% of control values depending on the muscle group, with the knee extensors measured at 30° being the relatively weakest group. There was a significant difference in strength between GMFCS levels in 4/6 muscle groups with a progressive reduction in strength in all muscle groups with increasing walking difficulty from GMFCS levels I to III. The greatest difference in strength between independent walkers and those dependent on walking aids was in the hip abductors and knee extensors at 30°, which are key muscle groups in sagittal and coronal plane walking stability. This has implications in targetting strength training to maximise functional outcomes.

The Effect of Coil Type and Navigation on the Reliability of Transcranial Magnetic Stimulation

The objective of this study was to investigate reliability of transcranial magnetic stimulation (TMS) parameters for three coil systems; hand-held circular and figure-of-eight and navigated figure-of-eight coils. Stimulus response curves, intracortical inhibition (SICI) and facilitation (ICF) were studied in the right first dorsal interosseus muscle of 10 healthy adults. Each coil system was tested twice per subject. Navigation was conducted by a custom built system. Cortical excitability showed moderate-to-good reliability for the hand-held and navigated figure-of-eight coils (Intraclass correlation coefficients (ICCs) 0.55-0.89). The circular coil showed poor reliability for motor evoked potential (MEP) amplitude at 120% resting motor threshold (RMT; MEP<;sub>;120<;/sub>;) and MEP sum (ICCs 0.09 & 0.48). Reliability for SICI was good for all coil systems when an outlier was removed (ICCs 0.87-0.93), but poor for ICF (ICCs <; 0.3). The circular coil had a higher MEP<;sub>;120<;/sub>; than the navigated figure-of-eight coil (p = 0.004). Figure-of-eight coils can be used confidently to investigate cortical excitability over time. ICF should be interpreted with caution. The navigation device frees the experimenter and enables tracking of the position of the coil and subject. The results help guide the choice of coil system for longitudinal measurements of motor cortex function.

Energy turnover in relation to slowing of contractile properties during fatiguing contractions of the human anterior tibialis muscle

Slowing and loss of muscle power are major factors limiting physical performance but little is known about the molecular mechanisms involved. The slowing might be a consequence of slow detachment of cross bridges and, if this were the case, then a reduction in the ATP cost of an isometric contraction would be expected as the muscle fatigued. The human anterior tibialis muscle was stimulated repeatedly under ischaemic conditions at 50 Hz for 1.6 s with a 50% duty cycle and muscle metabolites measured by 31P magnetic resonance spectroscopy. Over the course of 20 contractions the half‐time of relaxation increased from 36.5 ± 0.09 ms (mean ±s.e.m.) to 113 ± 17 ms and isometric force was reduced to 63 ± 3% of the initial value. ATP turnover was determined from the change in high energy phosphates and lactate production, the latter estimated from the change of intracellular pH. ATP turnover over the first three contractions was 2.45 ± 0.09 mm s−1 and decreased to 1.8 ± 0.06 mm s−1 over the last five tetani. However, when this latter value was normalised for the decrease in isometric force, it became 2.56 ± 0.3 mm s−1, which is the same as the turnover of the fresh muscle. The data suggest that the rate of cross bridge detachment is unaffected by fatigue and are consistent the suggestion that it is the rate of attachment which is slowed rather than the rate of detachment. The present results focus attention on stages in the cross bridge cycle concerned with attachment and the transition from low to high force states that may be influenced by metabolic changes in the fatiguing muscle.

Electromyographic Response to Manual Passive Stretch of the Hemiplegic Wrist: Accuracy, Reliability, and Correlation With Clinical Spasticity Assessment and Function

Background. The management of spasticity is important in neurorehabilitation and needs to be assessed accurately. The commonly used clinical tools have been criticized for lack of validity and sensitivity. Objective. To investigate the reliability of electromyographic (EMG) response to manual stretches of the hemiplegic wrist and its correlation with clinical assessments of spasticity and physical function. Methods. EMG activity was measured in 10 stroke patients and control participants (53.7 ± 10 and 32 ± 9.1 years respectively, mean ± SEM) during 3 cycles of 10 seconds passive manual movements of the wrist at 60 to 360° • s-1. Isometric maximal voluntary contractions (MVC) strength, range of movement (ROM) of the wrist flexors and extensors, spasticity (Modified Ashworth Scale [MAS]) and hand function (Block and Box Test [BBT]) were also assessed. Results. EMG activity of the stroke patients increased with velocity from 4% to 40% MVC (P < .001) but there was none in the controls. It was unaffected by repetition and good to moderate reliability occurred at all speeds (ICC, 0.71-0.81). EMG correlated negatively with MVC strength (r = -.9), active wrist flexion ROM ( r = -.8), and hand function scores (r = —.7), but not with clinical measures of spasticity except at the lowest velocity (r = .72). Conclusions. Consistent and accurate stretch velocities and EMG responses can be achieved with manual wrist stretches for the assessment of the neural component of spasticity. These objective tests did not correlate well with the standard clinical assessment of spasticity. They showed significant negative relationships with function, indicating that increased reflex excitability contributes to hand disability after stroke.

Effect of manual therapy techniques on the stretch reflex in normal human quadriceps

The effect of four manual therapy techniques on the quadriceps stretch reflex amplitude (elicited by mechanical vibration) was studied in a randomized, controlled trial in 120 (20 in each of six groups) healthy human subjects aged 18-64 years. Passive and active techniques were studied; each under static and dynamic conditions. The passive procedures were massage (static) and knee oscillation (dynamic) for 5 min. Active techniques involved eight repetitions of isometric quadriceps contractions (static) and leg extension (dynamic). The two static techniques had no effect on the stretch reflex amplitude. Both dynamic techniques caused a reduction (active by 25%, p < 0.00001 and passive 12%, p < 0.05). Only the active, dynamic technique caused a greater change than in the control group (p < 0.005). The effect lasted for less than 1 min. These data question the ability of such techniques to make clinically valid changes in motoneuron excitability. Further studies are required on those with neuromuscular pathology, who may respond differently to normal subjects.

The use of minimally invasive techniques in multi-level surgery for children with cerebral palsy: PRELIMINARY RESULTS

This study compares the initial outcomes of minimally invasive techniques for single-event multi-level surgery with conventional single-event multi-level surgery. The minimally invasive techniques included derotation osteotomies using closed corticotomy and fixation with titanium elastic nails and percutaneous lengthening of muscles where possible. A prospective cohort study of two matched groups was undertaken. Ten children with diplegic cerebral palsy with a mean age of ten years six months (7.11 to 13.9) had multi-level minimally invasive surgery and were matched for ambulatory level and compared with ten children with a mean age of 11 years four months (7.9 to 14.4) who had conventional single-event multi-level surgery. Gait kinematics, the Gillette Gait Index, isometric muscle strength and gross motor function were assessed before and 12 months after operation. The minimally invasive group had significantly reduced operation time and blood loss with a significantly improved time to mobilisation. There were no complications intra-operatively or during hospitalisation in either group. There was significant improvement in gait kinematics and the Gillette Gait Index in both groups with no difference between them. There was a trend to improved muscle strength in the multi-level group. There was no significant difference in gross motor function between the groups. We consider that minimally invasive single-event multi-level surgery can be achieved safely and effectively with significant advantages over conventional techniques in children with diplegic cerebral palsy.

Effect of recommended positioning on stroke outcome at six months: a randomized controlled trial

Objective: To evaluate the effect on patient outcome of a teaching package for nurses designed to improve the positioning of stroke patients. Design: Cluster randomized controlled trial with six-month follow-up. Setting: Ten stroke rehabilitation hospital units located within one UK inner city region. These were randomized to control or intervention group. Subjects: A sample of 120 patients admitted within four weeks of a first stroke and with a hemiplegia. No eligible patient refused to participate. Eighty-three (69%) completed the study. Intervention: All nursing staff on the intervention units received a group teaching package to improve their clinical practice in patient positioning. Main outcome measure: Rivermead Mobility Index (RMI) at six months post stroke. Patients position was recorded using an established observational tool. Results: After the teaching there was some evidence of better positioning in the intervention than the control group (difference in percentage of correct positions per patient 4.9%, 95% confidence interval (CI-0.1% to 9.9%, p-0.055). There was no evidence of differences between the two groups in any of the outcome measures at six months although there was a trend towards increased elbow flexor tone in the control group. Conclusions: A teaching intervention to improve patient positioning made no significant impact on outcome at six months post stroke. However, following the teaching there was only a slightly higher incidence of recommended patient positioning within the intervention group. Thus, a teaching package may not be powerful enough to enable any effect on patient outcome to be measured.

Skeletal Muscle Pain and Exercise

Summary This review article considers what is known about the mechanism and aetiology of skeletal muscle pain, in both health and disease. The role of physiotherapy in muscle pain is discussed.

Correction to Why is the Metabolic Efficiency of FES Cycling Low

In the above titled paper (ibid., vol. 17, no. 3, pp. 263-269, Jun. 09), the last paragraph of Section IV should appear as it is presented here.