Objective: To determine intra-rater and inter-rater reliability of ultrasound imaging for measuring muscle and non-contractile (subcutaneous fat and perimuscular fascia) tissue thickness of the anterior thigh.Approach: Ultrasound imaging has been used for clinical research to assess the morphology and cross-sectional area of muscles and other musculoskeletal structures.Repeatability of measurements with the ultrasound imaging technique between operators and test re-test reliability are important and need to be established for specific muscles.Twenty-four healthy moderately active adults (aged 36-64 years), underwent B-mode ultrasound imaging by two investigators.The anterior thighs were scanned at a site two-thirds of the distance between the anterosuperior iliac spine and the superior pole of the patella.Intraclass Correlation Coefficients (ICCs, model 3,1 for inter-rater and 3,2 for intra-rater reliability betweendays) with 95% confidence intervals (CI) was used to assess reliability.Main results: Inter-rater reliability of ultrasound imaging measurements were ICC3,1 of 0.98 (95% CI: 0.95-0.99)for muscle thickness, 0.81 (95% CI: 0.60-0.91)for subcutaneous fat, 0.78 (95% CI: 0.56-0.90)for non-contractile tissue (subcutaneous fat combined with perimuscular fascia), and 0.70 (95% CI: 0.42-0.86)for perimuscular fascia.Intra-rater reliability values were ICC3,2 0.96 (95% CI: 0.90-0.98)for muscle thickness, 0.99 (95% CI: 0.97-0.99)for subcutaneous fat, 0.98 (95% CI: 0.96-0.99)for non-contractile tissue, and -0.02 (95% CI: -0.41-0.38)for perimuscular fascia.Significance: The present findings indicate very high inter-rater and intra-rater reliability of ultrasound imaging thickness measurements of the quadriceps muscles and non-contractile tissue of the anterior thigh, while perimuscular fascia measurements alone were not reliable between days.
Objective: To investigate the effects of tilt table incline and knee flexion angle on the degree of weight bearing and forces exerted across the supporting straps. Design: A quantitative and exploratory study to investigate the effects of a mechanical procedure. Setting: Physiotherapy gymnasium. Subjects: Twelve healthy subjects (9 female, 3 male) aged 22–45 years. Interventions: Subjects stood on a tilt table, on two occasions, with simulated contractures of 10° and 40° knee flexion. Nine tilt angles, between 10° and 90°, were maintained for 1 minute each in random order. Main outcome measures: Force was recorded from single-point load cells placed under the feet, and at knee and chest straps. Results: The degree of simulated knee contracture (10° or 40°) influenced the distribution of forces at different recording sites. Weight bearing increased with table incline and was significantly less with the 40° than the 10° knee angle ( p < 0.001). Conversely, forces across the knee straps were systemically higher with the 40° knee angle ( p < 0.0001). The effects were accentuated by greater body weight. Forces across the chest strap also increased with tilt and were significantly larger with the 40° knee angle ( p < 0.05). Conclusions: The relationships between table incline, angle of knee flexion and distribution of forces generated during tilt table standing have been quantified and described. Standing with flexed knees involved less weight bearing under the feet and greater force exerted across the supporting straps. These effects were more pronounced at the higher knee angle and with greater body weight, and could be modified by reducing table incline.
Inactive older adults tend to have decreased strength and balance compared with their more active peers. Playing golf has the potential to improve strength and balance in older adults. The aim of the study was to compare the strength and balance of recreational golfers with non-golfers, aged 65-79 years. Grip strength, single leg balance, and Y Balance Test (YBT) were assessed. Golfers (n = 57) had significantly (right, p = .042; left, p = .047) higher maximal grip strength, than non-golfers (n = 17). Single leg stance times were significantly longer in golfers (right, p = .021; left, p = .001). Normalized YBT reach distances were significantly greater for golfers than non-golfers for composite, posteromedial, and posterolateral directions on both right and left legs. Playing golf appears to be associated with better grip and both static and dynamic balance in 65-79 year olds, indicating that a study of the effects of playing golf is warranted through a larger, fully powered, longitudinal study.
Abstract Background The use of large-scale pooled analyses and data sharing is a potential source to generate evidence to address complex scientific challenges and develop strategies to promote healthy ageing. However, the success of such analyses depends on robust measurements of musculoskeletal (MSK) health in ageing. Simple tests indicative of MSK health and suitable for use with older people are required. This study aims to assess the discriminatory ability of a combination of routine physical function tests and novel measures, notably muscle mechanical properties and ultrasound imaging of thigh composition (relative contribution of muscle and subcutaneous adipose tissue) to classify healthy individuals according to their age and gender. Methods This cross-sectional study included 138 community-dwelling, self-reported healthy males and females (65 young, mean age±SD = 25.7±4.8 years; 73 older, 74.9±5.9 years). Handgrip strength; quadriceps strength; respiratory peak flow; timed up and go; stair climbing; anterior thigh tissue thickness (using ultrasound imaging), muscle mechanical properties (stiffness, tone and elasticity; Myoton technology); and self-reported health related quality of life (SF36) were assessed. Stepwise linear discriminant analysis was used to classify cases based on criterion variable derived from the known effects of age on physical function. Results Combining conventional physical function tests with novel measures, revealed two discriminant functions which significantly (Wilks's λ = 0.05, 0.34; p>0.001) classified 89% of grouped cases with 11% error rate using leave-one-out cross-validation. Seven variables associated with grip strength, peak flow, timed up and go, anterior thigh thickness, and muscle mechanical properties demonstrated high discriminant ability (p>0.05 correlation with discriminant functions) to classify healthy people. Conclusions The present study provides reference data for comparison with clinical populations and a comprehensive battery of non-invasive dry biomarkers with high discriminant ability indicative of musculoskeletal health. The most sensitive novel biomarkers require no volition, highlighting potentially useful tests for screening and monitoring effects of interventions on MSK health for vulnerable older people with pain or cognitive impairment. Older misclassified cases who appeared younger than predicted support the need for studies of older people with different habitual activity levels, to provide relevant reference values for assessment, so rehabilitation goals are targeted appropriately.
Human adductor pollicis was fatigued during circulatory occlusion by supramaximal stimulation via the ulnar nerve using intermittent trains of stimuli in ascending (1, 10, 20, 50 and 100 Hz) and descending (100, 50, 20, 10 and 1 Hz) frequencies to investigate the contribution of relaxation rate slowing and post‐tetanic potentiation (PTP) to fatigue resistance. At 50 and 100 Hz force was initially well maintained despite a marked loss of excitation as indicated by EMG, demonstrating the operation of a high‐frequency ‘safety factor’ which appeared independent of the pattern of stimulation. At 10 Hz, force was initially potentiated before declining during both activity series. Potentiation was greater during the descending frequency series and the rate of decline of force, or fatigability, was reduced. The ‘extra’ low‐frequency potentiation at 10 Hz was not simply the result of PTP of twitch force, since this declined more during the descending than during the ascending series, nor the result of maximal relaxation rate changes which were identical for both fatiguing series. It is hypothesized that the extra potentiation and reduced fatigability at low stimulation frequencies, when preceded by high frequency, is the result of increased myofibrillar Ca 2+ availability and/or sensitivity. These findings may have important practical implications in relation to functional electrical stimulation techniques as used in paraplegia and in other areas of muscle research where fatigue is to be minimized.
Objective: To determine the intra-rater reliability of a newly developed movement screening tool; the ‘Movement control screen for older people in community settings’. The movement screening tool aims to identify movement control impairments which can potentially influence movement function. Method: Thirty one active female recreational golfers, aged 65-77 years, carried out three movement control tests included in the screening tool. Performance was videorecorded to enable repeated ratings. Each test was evaluated by criteria which were rated as pass or fail and ratings were carried out three weeks apart to examine intra-rater reliability. Reliability was assessed using percentage agreement and Cohen’s Kappa. Results: Percentage agreement for each test ranged from 93.0-97.3%, with an overall mean agreement of 95.5%. Kappa values for test scores ranged from 0.35-0.90. Percentage agreement for individual criteria ranged from 83.0-100.0%, with kappa values ranging from 0.00-1.00. Discussion: Acceptable intra-rater reliability was established for overall tests scores of the screening tool but certain criteria were identified as being less reliable than others. Recommendations are made for refinement of some criteria to improve reliability of the screening tool.
A simple tool to estimate loading on the lower limb joints outside a laboratory may be useful for people who suffer from degenerative joint disease. Here, the accelerometers on board of wearables (smartwatch, smartphone) were used to estimate the load rate on the lower limbs and were compared to data from a treadmill force plate. The aim was to assess the validity of wearables to estimate load rate transmitted through the joints.Twelve healthy participants (female n = 4, male n = 8; aged 26 ± 3 years; height: 175 ± 15 cm; body mass: 71 ± 9 kg) carried wearables, while performing locomotive activities on an anti-gravity treadmill with an integrated force plate. Acceleration data from the wearables and force plate data were used to estimate the load rate. The treadmill enabled 7680 data points to be obtained, allowing a good estimate of uncertainty to be examined. A linear regression model and cross-validation with 1000 bootstrap resamples were used to assess the validation.Significant correlation was found between load rate from the force plate and wearables (smartphone: R2=0.71 ; smartwatch: R2=0.67 ).Wearables' accelerometers can estimate load rate, and the good correlation with force plate data supports their use as a surrogate when assessing lower limb joint loading in field environments.
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