Influence of ankle plantar flexor muscle architecture and strength on gait in boys with haemophilia in comparison to typically developing children.

Altered gait patterns, muscle weakness and atrophy have been reported in young boys with severe haemophilia when compared to unaffected peers. The aim of this study was to determine whether lateral gastrocnemius muscle size and architecture influenced biomechanical walking patterns of boys with haemophilia and if these relationships differed from age-matched typically developing boys. Biomechanical function of the knee and ankle during level walking, lateral gastrocnemius anatomical cross-sectional area, thickness, width, fascicle length and pennation angle and ankle plantar flexor muscle strength were recorded in 19 typically developing boys aged 7-12 years and 19 age-matched haemophilic boys with a history of ankle joint bleeding. Associations between gait, strength and architecture were compared using correlations of peak gait values. Haemophilic boys walked with significantly larger (P < 0.05) ankle dorsi flexion angles and knee flexion moments. The ankle plantar flexor muscles of haemophilic boys were significantly weaker and smaller when compared to typically developing peers. In the typically developing boys there was no apparent association between muscle architecture, strength and walking patterns. In haemophilic boys maximum muscle strength and ACSA normalized torque of the ankle plantar flexors together with the muscle width, thickness, fascicle length and angulation (P < 0.05) were associated with motion at the ankle and peak moments at the knee joint. Muscle strength deficits of the ankle plantar flexors and changes in muscle size and architecture may underpin the key biomechanical alterations in walking patterns of haemophilic boys with a history of ankle joint bleeding.

Outcome measures monitoring physical function in children with haemophilia: a systematic review.

Our objective was to provide a synthesis of measurement properties for performance-based outcome measures used to evaluate physical function in children with haemophilia. A systematic review of articles published in English using Medline, PEDro, Cinahl and The Cochrane Library electronic databases was conducted. Studies were included if a performance-based method, clinical evaluation or measurement tool was used to record an aspect of physical function in patients with haemophilia aged ≤ 18 years. Recording of self-perceived or patient-reported physical performance, abstracts, unpublished reports, case series reports and studies where the outcome measure was not documented or cross-referenced was excluded. Description of outcome measures, patient characteristics, measurement properties for construct validity, internal consistency, repeatability, responsiveness and feasibility was extracted. Data synthesis of 41 studies evaluating 14 measures is reported. None of the outcome measures demonstrated the requirements for all the measurement properties. Data on validity and test-retest repeatability were most lacking together with studies of sufficient size. Measurement of walking and muscle strength demonstrated good repeatability and discriminative properties; however, correlation with other measures of musculoskeletal impairment requires investigation. The Haemophilia Joint Health Score demonstrated acceptable construct validity, internal consistency and repeatability, but the ability to discriminate changes in physical function is still to be determined. Rigorous evaluation of the measurement properties of performance-based outcome measures used to monitor physical function of children with haemophilia in larger collaborative studies is required.

Low intensity strength training for ambulatory stroke patients.

PURPOSE: To investigate feasibility and effectiveness of an individually-directed, group strength-training programme on knee muscle strength after stroke. METHOD: Ten volunteers (62 +/- 11 years, mean +/- SD), 6 - 12 months after first-ever unilateral stroke, walking independently with or without aids were recruited. Using an A1-B-A2 design, 3 sets of baseline measures were taken at 2 weekly intervals; volunteers then attended twice weekly sessions of low intensity progressive strengthening exercises and were assessed after each series of 8 sessions to a maximum of 24 sessions; post training, measures were repeated after 4 - 6 weeks. Measures included isometric and concentric knee extensor muscle strength and 10 m walking velocity. RESULTS: Strength of knee extensor muscles was improved after training (ANOVA, p < 0.05). On cessation of training, isometric strength increased by 58 +/- 19% and concentric strength at 30 degrees /s by 51 +/- 14%; walking velocity quickened from 0.47 +/- 0.06 m x s-1 to 0.57 +/- 0.08 m x s-1 (t = -3.31, p < 0.01). These gains were maintained 4 - 6 weeks after completion of training. CONCLUSIONS: These findings support the use of low intensity strength training after stroke and confirm published evidence. It was feasible for one therapist to deliver the training programmes for 4 - 6 participants at a time; an important feature when resources are limited.

The effect of aerobic training on rehabilitation outcomes after recent severe brain injury: a randomized controlled evaluation.

OBJECTIVE: To examine the impact of fitness training with recently brain-injured inpatients on exercise capacity and functional and psychologic outcome measures. DESIGN: A randomized controlled trial of exercise versus relaxation training for 3 months. Blind assessments were conducted before and after the end of a 12-week training program, as well as at follow-up assessment 12 weeks posttraining. SETTING: Four regional neurologic inpatient rehabilitation units. PATIENTS: Of 157 patients recruited 24 +/- 14 weeks after single-incident brain injury, 142 patients were assessed at week 12, and 128 patients at follow-up. INTERVENTIONS: Patients were randomized between cycle ergometer aerobic training and a relaxation training control condition, which was theoretically inert with respect to cardiovascular fitness. MAIN OUTCOME MEASURES: Validation of exercise training (peak work rate, peak heart rate, body mass index); mobility and physical function (modified Ashworth scale, Berg balance scale, Rivermead Mobility Index, 10-m walk velocity); disability and dependency (Barthel index, FIMtrade mark instrument, Nottingham Extended Activities of Daily Living); and psychologic function (fatigue questionnaire, Hospital Anxiety and Depression Scale). RESULTS: Significant improvements in exercise capacity (p <.05) in the exercise training group (n = 70) relative to the control group (n = 72) were not matched by greater improvements in functional independence, mobility, or psychologic function, at either 12 weeks or follow-up. CONCLUSIONS: The benefits of improved cardiovascular fitness did not appear to extend to measurable change in function or psychologic state.

High-intensity cycling exercise after a stroke: a single case study.

Aerobic exercise training has demonstrated positive effects after brain injury. However, therapists express concern regarding the use of effortful exercise in individuals presenting with spasticity or involuntary muscle activity. This study aimed to address this concern and to evaluate whether an intervention of maximal intensity cycling exercise impaired an individual's ability to actively extend his hemiparetic elbow. Using a single case design, it was shown that active elbow extension improved during the period of this investigation, and was not impaired immediately following maximal cycling exercise.

Therapeutic possibilities of chronic low frequency electrical stimulation in children with Duchenne muscular dystrophy.

To evaluate the therapeutic possibilities of chronic electrical stimulation, muscle function studies and quantitative tests of physical assessment were used to monitor the response of quadriceps femoris to prolonged low frequency stimulation. Comparative studies of the maximum voluntary and electrically elicited responses of muscles of young ambulant children with Duchenne muscular dystrophy, when compared to those of normal children's muscles, revealed lower values of maximum voluntary contraction, significant slowing (P less than 0.001) of mean relaxation times and a higher resistance to fatigue testing. Intermittent chronic low frequency stimulation resulted in a significant (P less than 0.01) increase in mean maximum voluntary contraction of the stimulated muscles compared with the mean force exerted by the unstimulated control muscles. There are clear therapeutic possibilities for the use of chronic low frequency stimulation in these children.

Changes in center of gravity in boys with Duchenne muscular dystrophy.

A study was undertaken, using methods of stabilometry to compare stability of stance in normal children (n = 37) and those with Duchenne muscular dystrophy (n = 61). The purpose of this study was to monitor changes in the locus of the center of gravity and the range and frequency of sway and to evaluate the effect of orthotic application in an attempt to obtain information that would assist further development of orthoses. In group 1, boys with Duchenne muscular dystrophy who were still walking without assistance (mean age 7.2 +/- 1.76 years), the analysis of sway showed that, between 5 and 6 years of age, the boys already had ranges of anteroposterior (A/P) and lateral (Lat) sway that were significantly greater than those found in normal children (A/P P less than 0.05, Lat P less than 0.01). In group 2, boys with Duchenne muscular dystrophy when orthoses had been introduced (n = 23, mean age 10.4 +/- 1.47 years), the center of gravity was returned to a more normal position. There was a reduction of the anteroposterior range of sway, but the lateral range of sway remained significantly greater (P less than 0.01) as did the frequency of sway in both the anteroposterior and lateral directions (A/P P less than 0.001, Lat P less than 0.001).

Responses of muscles of patients with Duchenne muscular dystrophy to chronic electrical stimulation.

The effect of chronic low frequency stimulation on the tibialis anterior muscle of children with Duchenne muscular dystrophy was investigated. Baseline data from 16 boys established low values of maximum voluntary contraction which did not improve with age. Studies of the contractile properties revealed significant slowing (p less than 0.001) of mean relaxation time compared to that of normal children's muscles. There was no loss of force during fatigue testing, as in normal children, but in contrast to normal children, there was no potentiation at lower frequencies of stimulation. Intermittent chronic low frequency stimulation of muscles in six young ambulant children with Duchenne muscular dystrophy resulted in a significant increase (p less than 0.05) in mean maximum voluntary contraction compared with the mean forces exerted by the unstimulated control muscles of the contralateral leg.

Effects of chronic low frequency electrical stimulation on normal human tibialis anterior muscle.

The loss of force that occurred during intermittent electrically evoked tetanic contractions was determined for the tibialis anterior muscle of normal subjects. Adult muscles showed a characteristic reduction of tension over the first two to three minutes until a steady plateau was reached. Muscles of young children showed no comparable decrease of the initial tension in response to this method of fatigue testing. After fatigue the muscles of both groups of subjects produced a higher proportion of tension at lower rates of stimulation. Following prolonged chronic low frequency stimulation at 8-10 Hz, adult muscles showed a significant increase (p less than 0.01) in fatigue resistance compared to unstimulated control: the muscles of the normal child showed no measured change. It is concluded that it is possible to alter the properties of adult human muscle by superimposed low frequency electrical stimulation.

Quantitation of muscle function in children: a prospective study in Duchenne muscular dystrophy.

A protocol has been developed for the quantitative assessment of muscle function in children with muscle disease. It includes total muscle strength (% MRC) based on a clinical assessment of strength of 32 groups using the 6-point MRC grading; the force of 8 selected muscle groups measured with a specially designed electromyometer; a motor ability score based on 20 consecutive motor activities; walking times over 28 and 150 feet, and recording of muscle contractures. A 3-year sequential study of 61 boys with Duchenne dystrophy showed progressive decline of muscle strength with age, a close correlation of total strength and the motor ability score (r = 0.89), and a curvilinear relationship of muscle strength with walking times over 28 and 150 feet (r = 0.78 and 0.79, respectively). A profile of the natural progression of Duchenne dystrophy has been established which could serve as a reference base for the assessment of cases at varying ages and their response to therapy and management.