Short-Term Muscle Power Is Related to Lower Limb Muscle Volume in Young Children.

PURPOSE: Muscle power is a component of muscular fitness and is proportional to its volume. Reduced muscular fitness in children is linked to negative health outcomes. Associations between muscle volume (MV) and power have not been examined in young children and could reveal important insights into early neuromuscular development. METHOD: Forty-four children (2-8 y) completed 3 tests of short-term muscular power: repeated anaerobic sprint test, vertical jump, and horizontal jump. MV was assessed using 3D ultrasound for 3 lower limb muscles (rectus femoris, medial gastrocnemius, and tibialis anterior) and summed for across legs. Associations between muscular power and summed MV were assessed using Pearson correlation (r). Sex-based differences in muscular power and MV were assessed using 1-way analysis of covariance. RESULTS: Moderate-strong associations (r = .57 - .87) were found between muscular power and summed MV. No differences were found between boys and girls for height, weight, MV, or muscular power. CONCLUSIONS: Young children who have larger lower limb muscles perform better at tasks dependent on short-term muscular power, such as running and jumping, compared with children with smaller muscles. Sex-based differences in short-term muscular power do not exist in young children and reflect similar anthropometry, including lower limb MV.

The immediate effect of multidirectional elastic tape on the passive mechanical properties of the ankle joint.

This study examined the immediate effects of multidirectional elastic tape (MET) on passive ankle joint torque in healthy adults. A randomised crossover trial evaluated four tape conditions (no-tape-NT, low-tension-LT, medium-tension-MT, and high-tension-HT) at two angular speeds on peak dorsiflexion torque, low- (stiffness 1) and high-torque stiffness (stiffness 2), area under the loading curve (AUC) and hysteresis. Twenty-two adults completed the study (17 females; mean (SD): age 26.0 (6.9) years, height 1.7 (0.1) m, body mass 71.1 (20.2) kg. There was no significant condition-by-speed interaction for any ankle torque variable. There was a significant main effect of condition on peak dorsiflexion torque, stiffness 1, and AUC, but not stiffness 2 or hysteresis. Post-hoc tests revealed that peak dorsiflexion torque, stiffness 1 and AUC were significantly lower in the NT condition, compared to the three taped conditions, and between the LT and HT conditions, though the effect sizes were considered small. MET applied with increasing levels of pre-tension, led to a small and incremental increase in stretch resistance and elastic energy stored (range 5.5% to 12.5%) during passive ankle dorsiflexion. Importantly, effect sizes were small and may not translate to measurable improvements in muscle-tendon unit performance during dynamic exercise.

Medial gastrocnemius growth in children who are typically developing: Can changes in muscle volume and length be accurately predicted from age?

Muscle size is an important determinant of muscular fitness and health, and so it is important to have accurate estimates of actual muscle growth in children. This study compared actual versus age-predicted growth rates of the medial gastrocnemius (MG) muscle in young children over a 12-month period. Three-dimensional ultrasound was used to measure MG length and volume in 50 children (mean ± standard deviation [SD] age = 70.3 ± 29.9 months) to establish age-predicted muscle growth rates using a least-squares linear regression. Twenty children (mean ± SD age = 78.5 ± 27.2 months) were followed up at 6 and 12 months to establish actual muscle growth of MG volume and length. These data were then compared to their age-predicted muscle growth from the linear regression equation using paired t-tests and Bland-Altman limits of agreement method. Age-predicted MG growth significantly underestimated actual muscle growth for both volume and length at each timepoint. On average, actual muscle volume and length were 11.5% and 21.5% greater than the age-predicted volume and length respectively. Caution is warranted when predicting future muscle size in young children based solely on age.

The effect of deloading tape on medial gastrocnemius muscle fascicle behaviour during dynamic exercise.

This study examined the effect of diamond deloading tape on medial gastrocnemius (MG) muscle behaviour during exercise in healthy adults (n = 27). A randomised cross-over trial assessed the effect of tape (no-tape, sham-tape and deload-tape) on ankle and MG fascicle kinematics during three heel raise-lower exercises [double leg (DL), single leg (SL) and loaded single leg (LSL)]. There was no effect of tape on standing fascicle length (FL) or pennation angle (PA), or ankle or knee joint angle. There was a significant effect of tape on ankle kinematics for all exercises. Both the deload-tape and sham-tape resulted in less ankle plantar flexion but had no effect on dorsiflexion. There was a significant effect of tape on FL change for the SL and LSL exercise. Compared to no-tape, the deload-tape resulted in less fascicle shortening during ankle plantar flexion, and more fascicle lengthening during ankle dorsiflexion. For the LSL exercise, deload-tape caused MG fascicles to operate at longer lengths, for a given joint angle. Diamond taping, with or without added tension, has only a small effect on ankle and MG fascicle kinematics during the heel raise-lower exercise. With the exception of the LSL exercise, both tape conditions resulted in similar changes in the FL-angle relations.

Three-dimensional morphology and volume of the free Achilles tendon at rest and under load in people with unilateral mid-portion Achilles tendinopathy.

NEW FINDINGS: What is the central question of this study? The aim was to determine the effect of mid-portion Achilles tendinopathy (MAT) on free Achilles tendon three-dimensional morphology and volume at rest and under load in people with unilateral MAT. What is the main finding and its importance? Tendinopathic tendon had a larger resting tendon cross-sectional area and anteroposterior diameter relative to healthy tendon. When loaded, tendinopathic tendon experienced a reduction in transverse morphology (i.e. cross-sectional area, anteroposterior and mediolateral diameters) and overall volume reduction. In contrast, the healthy tendon remained isovolumetric and bulged along the anteroposterior axis. These findings suggest a fundamental reorganization of tendinopathic tendon matrix components and altered tendon fluid content when under load. ABSTRACT: Mid-portion Achilles tendinopathy (MAT) adversely affects free Achilles tendon (AT) structure and composition. However, it is not known how these pathological alterations associated with MAT change the normal three-dimensional (3-D) morphology of free AT at rest and under load throughout the entire free tendon length. Here, we used 3-D ultrasound to examine the effect of unilateral MAT on free tendon 3-D morphology [length, cross-sectional area (CSA), anteroposterior (AP) diameter and mediolateral (ML) diameter] and volume at rest and during a submaximal (50%) voluntary isometric plantarflexion contraction bilaterally in individuals with unilateral MAT (n = 10) compared with a matched healthy control group (n = 10). The tendinopathic free AT had a greater CSA relative to the control tendons along the entire tendon length, which was mainly driven by a greater tendon AP diameter. Under load, the tendinopathic tendon experienced greater longitudinal and transverse strains than the control tendons. In contrast to the control tendons, which experienced a reduction in tendon CSA and ML diameter, bulged along the AP axis and behaved isovolumetrically under load, the tendinopathic tendon experienced a reduction in tendon CSA, AP diameter and ML diameter and an overall volume reduction. Overall, these findings suggest that the magnitude of longitudinal strain and volume change and the corresponding magnitude and direction of transverse strain under load are altered in MAT compared with normal tendon. These findings are indicative of a fundamental reorganization of the tendon matrix and alterations in tendon fluid content and distribution under load in tendinopathic tendon.

The tendinopathic Achilles tendon does not remain iso-volumetric upon repeated loading: insights from 3D ultrasound.

Mid-portion Achilles tendinopathy (MAT) alters the normal three-dimensional (3D) morphology of the Achilles tendon (AT) at rest and under a single tensile load. However, how MAT changes the 3D morphology of the AT during repeated loading remains unclear. This study compared the AT longitudinal, transverse and volume strains during repeated loading of the tendinopathic AT with those of the contralateral tendon in people with unilateral MAT. Ten adults with unilateral MAT performed 10 successive 25 s submaximal (50%) voluntary isometric plantarflexion contractions with both legs. Freehand 3D ultrasound scans were recorded and used to measure whole AT, free AT and proximal AT longitudinal strains and free AT cross-sectional area (CSA) and volume strains. The free AT experienced higher longitudinal and CSA strain and reached steady state following a greater number of contractions (five contractions) in the tendinopathic AT compared with the contralateral tendon (three contractions). Further, free tendon CSA and volume strain were greater in the tendinopathic AT than in the contralateral tendon from the first contraction, whereas free AT longitudinal strain was not greater than that of the contralateral tendon until the fourth contraction. Volume loss from the tendon core therefore preceded the greater longitudinal strain in the tendinopathic AT. Overall, these findings suggest that the tendinopathic free AT experiences an exaggerated longitudinal and transverse strain response under repeated loading that is underpinned by an altered interaction between solid and fluid tendon matrix components. These alterations are indicative of accentuated poroelasticity and an altered local stress-strain environment within the tendinopathic free tendon matrix, which could affect tendon remodelling via mechanobiological pathways.

Reliability of Achilles Tendon Moment Arm Measured In Vivo Using Freehand Three-Dimensional Ultrasound.

This study investigated reliability of freehand three-dimensional ultrasound (3DUS) measurement of in vivo human Achilles tendon (AT) moment arm. Sixteen healthy adults were scanned on 2 separate occasions by a single investigator. 3DUS scans were performed over the free AT, medial malleolus, and lateral malleolus with the ankle passively positioned in maximal dorsiflexion, mid dorsiflexion, neutral, mid plantar flexion and maximal plantar flexion. 3D reconstructions of the AT, medial malleolus, and lateral malleolus were created from manual segmentation of the ultrasound images and used to geometrically determine the AT moment arm using both a straight (straight ATMA) and curved (curved ATMA) tendon line-of-action. Both methods were reliable within- and between-session (intra-class correlation coefficients > 0.92; coefficient of variation < 2.5 %) and revealed that AT moment arm increased by ∼ 7 mm from maximal dorsiflexion (∼ 41mm) to maximal plantar flexion (∼ 48 mm). Failing to account for tendon curvature led to a small overestimation (< 2 mm) of AT moment arm that was most pronounced in ankle plantar flexion, but was less than the minimal detectable change of the method and could be disregarded.

Three-dimensional morphology and strain of the human Achilles free tendon immediately following eccentric heel drop exercise.

Our understanding of the immediate effects of exercise on Achilles free tendon transverse morphology is limited to single site measurements acquired at rest using 2D ultrasound. The purpose of this study was to provide a detailed 3D description of changes in Achilles free tendon morphology immediately following a single clinical bout of exercise. Freehand 3D ultrasound was used to measure Achilles free tendon length, and regional cross-sectional area (CSA), medio-lateral (ML) diameter and antero-posterior (AP) diameter in healthy young adults (N=14) at rest and during isometric muscle contraction, immediately before and after 3×15 eccentric heel drops. Post-exercise reductions in transverse strain were limited to CSA and AP diameter in the mid-proximal region of the Achilles free tendon during muscle contraction. The change in CSA strain during muscle contraction was significantly correlated to the change in longitudinal strain (r=-0.72) and the change in AP diameter strain (r=0.64). Overall findings suggest the Achilles free tendon experiences a complex change in 3D morphology following eccentric heel drop exercise that manifests under contractile but not rest conditions, is most pronounced in the mid-proximal tendon and is primarily driven by changes in AP diameter strain and not ML diameter strain.

Maximal Lower Limb Strength in Patellar Tendinopathy: A Systematic Review With Meta-Analysis.

OBJECTIVE: To investigate whether lower limb strength is reduced in people with patellar tendinopathy (PT) compared with asymptomatic control individuals or the asymptomatic contralateral limb. DATA SOURCES: MEDLINE, PubMed, Scopus, and Web of Science. STUDY SELECTION: To be included in the systematic review and meta-analysis, studies were required to be peer reviewed, published in the English language, and case control investigations; include participants with a clinical diagnosis of PT and an asymptomatic control or contralateral limb group; and include an objective measure of lower limb maximal strength. DATA EXTRACTION: We extracted descriptive statistics for maximal strength for the symptomatic and asymptomatic limbs of individuals with PT and the limb(s) of the asymptomatic control group, inferential statistics for between-groups differences, participant characteristics, and details of the strength-testing protocol. The risk of bias was assessed using the Joanna Briggs Institute critical appraisal tool for analytical cross-sectional studies. DATA SYNTHESIS: Of the 23 included studies, 21 reported knee strength, 3 reported hip strength, and 1 reported ankle strength. Random-effects models (Hedges g) were used to calculate the pooled effect sizes (ESs) of muscle strength according to the direction of joint movement and type of contraction. The pooled ESs (95% CI) for maximal voluntary isometric contraction knee-extension strength, concentric knee-extension strength, and concentric knee-flexion strength were 0.54 (0.27, 0.80), 0.78 (0.30, 1.33), and 0.41 (0.04, 0.78), respectively, with all favoring greater strength in the asymptomatic control group. Researchers of 2 studies described maximal eccentric knee-extensor strength with no differences between the PT and asymptomatic control groups. In 3 studies, researchers measured maximal hip strength (abduction, extension, and external rotation), and all within-study ESs favored greater strength in the asymptomatic control group. CONCLUSIONS: Isometric and concentric knee-extensor strength are reduced in people with PT compared with asymptomatic control individuals. In contrast, evidence for reduced eccentric knee-extension strength in people with PT compared with asymptomatic control individuals is limited and inconsistent. Although evidence is emerging that both knee-flexion and hip strength may be reduced in people with PT, more examination is needed to confirm this observation.

Isokinetic Shoulder Strength and its Associations to Injury in Tactical Populations: A Critical Review.

The aim of this review is to evaluate existing isokinetic testing protocols for the shoulder in tactical occupations, document their shoulder strength profiles, and determine any associations to shoulder injury. Four electronic databases were searched (Medline/Pubmed, Ovid/Emcare, CINAHL/Ebsco and Embase) using the keywords police OR law enforcement, firefighter, military, AND isokinetic. Articles were eligible if they had at least one cohort of a tactical population and included isokinetic testing of the glenohumeral joint. The search yielded 275 articles. After screening for duplicates and inclusion criteria, 19 articles remained for review, six of which assessed injury correlation. 17 articles evaluated military personnel and two examined firefighters. Articles were categorized by study design, population, isokinetic protocols, strength outcome measures and statistical measures. Concentric internal rotation (IR) and external rotation (ER) strength at 60 degrees/second were reported most frequently (84% of cases). There was a paucity of testing speeds, repetition ranges and contraction types evaluated when compared to existing literature in other populations with high shoulder injury occurrence such as overhead and collision athletes. Outside of military cohorts, there is limited data available to characterise the isokinetic strength profile of the shoulder in tactical occupations. Meta-analysis for injury association was unable to be performed due to independent variable and statistical heterogeneity. However, a best evidence synthesis suggested conflicting evidence to support the association of injury with isokinetic strength testing in tactical populations. Future studies should prioritise prospective designs utilising variable speeds, repetition schemes and contraction types to better capture the dynamic occupational demands in tactical groups.

Tides of Change-Barriers and Facilitators to Beach Accessibility for Older People and People with Disability: An Australian Community Survey.

The beach is Australia's most popular recreational destination with participation in beach-based activities associated with a wide range of health and wellbeing benefits. Unfortunately, access to beach environments is not possible for many older people and people with a disability. The purpose of this study was to investigate the barriers and facilitators of beach accessibility using a framework that recognises the complex interconnections between blue space, accessibility, physical activity, and health and wellbeing. A 39-item anonymous online cross-sectional survey was developed and administered to explore the perspectives of older people and people with a disability regarding beach accessibility. In total, 350 people completed the survey (69% female, age range 2-90 years (mean = 52)). Disability was reported by 88% of respondents, with 77% requiring a community mobility aid. Two-thirds (68%) of respondents were unable to visit the beach as often as they wanted, with 45% unable to visit at all. The most frequently reported barriers to beach access included difficulty moving on soft sand (87%), no specialised mobility equipment (75%), and inaccessible lead-up pathways (81%). If beach access was improved, respondents reported they would visit the beach more often (85%), for longer (83%), and have an improved experience (91%). The most frequently reported facilitators to beach access were the presence of accessible lead-up pathways (90%), sand walkways (89%), and parking (87%). Older people and people with disability have limited beach access, primarily due to a lack of accessible equipment, excluding them from the wide range of health benefits associated with visiting the beach.

The immediate effect of unilaterally applied lumbar mobilisations on the passive straight leg raise and ninety-ninety test in asymptomatic adults: A randomised crossover trial.

OBJECTIVES: This study assessed the immediate effect of unilateral posterior-anterior lumbar mobilisations on trunk and lower limb flexibility in asymptomatic individuals. STUDY DESIGN: Randomised cross-over trial. PARTICIPANTS: Twenty-seven participants (age = 26.0 years ±6.4) with no current or recent history of lower back or leg pain/surgery completed the study. MAIN OUTCOME MEASURES: Participants attended two sessions, receiving either grade 3 ('treatment') or grade 1 ('sham') unilateral spinal mobilisations. Outcome measures (modified-modified Schober's test [MMST], ninety-ninety test [NNT], and passive straight-leg raise [PSLR]) were assessed immediately before and after (post-1 and post-2) the intervention. An instrumented hand-held dynamometer was used to measure the change in NNT and PSLR joint angle (deg) and passive stiffness (Nm/deg) pre- and post-intervention. RESULTS: The mean change in PSLR angle at the first (P1) and maximal (P2) point of discomfort following the treatment was 4.8° and 5.5°, and 5.6° and 5.7°, larger than the sham at post-1 and post-2, respectively. There was no effect of the treatment on the PSLR at P1 or P2 for the contralateral limb at either timepoint. There was no effect of the treatment on MMST distance, NNT angle or passive stiffness, or PSLR passive stiffness, for either limb. CONCLUSIONS: Immediate effects of unilateral posterior-anterior lumbar mobilisations in asymptomatic individuals are isolated to treatment side and limited to a small increase in PSLR range, with no change in lumbar motion or the NNT test.

Fixed-intensity exercise tests to measure exertional dyspnoea in chronic heart and lung populations: a systematic review.

INTRODUCTION: Exertional dyspnoea is the primary diagnostic symptom for chronic cardiopulmonary disease populations. Whilst a number of exercise tests are used, there remains no gold standard clinical measure of exertional dyspnoea. The aim of this review was to comprehensively describe and evaluate all types of fixed-intensity exercise tests used to assess exertional dyspnoea in chronic cardiopulmonary populations and, where possible, report the reliability and responsiveness of the tests. METHODS: A systematic search of five electronic databases identified papers that examined 1) fixed-intensity exercise tests and measured exertional dyspnoea, 2) chronic cardiopulmonary populations, 3) exertional dyspnoea reported at isotime or upon completion of fixed-duration exercise tests, and 4) published in English. RESULTS: Searches identified 8785 papers. 123 papers were included, covering exercise tests using a variety of fixed-intensity protocols. Three modes were identified, as follows: 1) cycling (n=87), 2) walking (n=31) and 3) other (step test (n=8) and arm exercise (n=2)). Most studies (98%) were performed on chronic respiratory disease patients. Nearly all studies (88%) used an incremental exercise test. 34% of studies used a fixed duration for the exercise test, with the remaining 66% using an exhaustion protocol recording exertional dyspnoea at isotime. Exertional dyspnoea was measured using the Borg scale (89%). 7% of studies reported reliability. Most studies (72%) examined the change in exertional dyspnoea in response to different interventions. CONCLUSION: Considerable methodological variety of fixed-intensity exercise tests exists to assess exertional dyspnoea and most test protocols require incremental exercise tests. There does not appear to be a simple, universal test for measuring exertional dyspnoea in the clinical setting.

The impact of a targeted education package on the knowledge, attitudes, and utilisation of patient reported outcome measures amongst chiropractors in Australia.

BACKGROUND: Patient Reported Outcome Measures (PROMs) have been shown to be valid and reliable indicators of health status and treatment outcomes, however, the current knowledge, understanding, and utilisation of PROMs within the Australian Chiropractic profession is limited. This study used the New World Kirkpatrick Model (NWKM) to evaluate whether an online PROM education package could improve knowledge, confidence, attitude, and utilisation of PROMs by chiropractors in Australia. METHODS: A longitudinal cohort interventional study of chiropractors in Australia. The recruitment phase and data collection period occurred from November 2020 - May 2021. Participants completed three online surveys two weeks before, four weeks after, and 12 weeks after receiving an online education package that included ten evidence-based region-specific modules on PROMs. Survey questions were grouped into five subthemes for analysis according to the NWKM levels: (1) Reaction; (2) Learning - knowledge; (3) Learning - confidence; (4) Behaviour - attitude; (5) and Behaviour - utilisation). RESULTS: Of the 116 participants that enrolled in the study, 43 completed all three survey and were included in the analysis. There was very positive reaction to the education package with mean response scores (1-5 Likert scale) for the reaction questions ranging from 3.75 to 4.43. There was a small, but significant, increase in knowledge (out of 32) at four weeks (24.3 ± 6.1) and 12 weeks after receiving the education package (27.2 ± 5.5), compared to baseline (27.4 ± 5.1). There was no effect of the intervention on clinician confidence or attitude towards PROMs. Utilisation of function- and pain-related PROMs did not change after the intervention. There was a small and significant (p < 0.05) increase in utilisation of health-related PROMs 12 weeks after the intervention. CONCLUSION: Despite modest improvements in knowledge, which were retained 12 weeks after the educational package was provided, there was no evidence that participant confidence, attitude, or utilisation of PROMs changed because of the intervention. While the respondents' have positive attitudes and beliefs regarding PROMs use, further education surrounding the clinical translation process into clinical practice is required. Caution is advised when interpreting these findings due to the low participant response and completion rate with the potential for selection bias and the inability to generalise the results.

The size and echogenicity of the tibialis anterior muscle is preserved in both limbs in young children with unilateral spastic cerebral palsy.

PURPOSE: The primary of this study was to compare the volume, length, echo intensity, and growth rate of the medial gastrocnemius (MG) and tibialis anterior (TA) muscle of both limbs (more-involved and less-involved) in children with unilateral spastic cerebral palsy (USCP), with those of an age-matched typically developing (TD) group. A secondary aim in the USCP group was to explore the associations between these muscle parameters and discrete ankle positions during phase of gait. METHODS: Muscle parameters were assessed using 3D ultrasound. Maximal ankle dorsiflexion in stance and swing during walking were determined from 2D video analysis. Group differences in muscle size and echo intensity were assessed using a two-way analysis of covariance (age-by-group), with the interaction term used to compare muscle growth rates. Associations between muscle parameters and maximal ankle dorsiflexion in stance and swing were assessed using backwards multiple linear regression analyses. RESULTS: The MG of both limbs in children with USCP had signs of impaired muscle development (smaller volume and length, higher echo intensity and lower growth rate). There was no evidence of impaired muscle development of TA between limbs or compared the TD children. Tibialis anterior volume, length, echo intensity and MG volume explained 66% and 83% of the variance in maximal ankle dorsiflexion position in the stance and swing phases of walking, respectively. CONCLUSIONS: Unlike the MG, the TA volume and growth rate in children with USCP are equivalent between limbs and compared to TD children. For the more-involved limb only, TA volume, length, and echo intensity appear associated with maximal ankle dorsiflexion during walking and represent important muscle parameters that could be targeted in with early exercise therapy.Implications for rehabilitationTibialis anterior (TA) size and echogenicity appear normal in both limbs in young children with unilateral spastic cerebral palsy (USCP); findings that could indicate sufficient mechanical stimulus and muscle anabolism to maintain normal muscle growth.Tibialis anterior size and echogenicity are associated with maximal ankle dorsiflexion in both stance and swing phase of walking in young children with USCP; though such relations appear isolated to the more-involved limb.Early therapeutic interventions that target TA are likely to be successful in maintaining muscle size and may offset the negative effects of medial gastrocnemius atrophy in the development of fixed ankle equinus of the more-involved limb and improve ankle positioning during gait.

Free Achilles tendon strain during selected rehabilitation, locomotor, jumping, and landing tasks.

A better understanding of the strains experienced by the Achilles tendon during commonly prescribed exercises and locomotor tasks is needed to improve efficacy of Achilles tendon training and rehabilitation programs. The aim of this study was to estimate in vivo free Achilles tendon strain during selected rehabilitation, locomotor, jumping, and landing tasks. Sixteen trained runners with no symptoms of Achilles tendinopathy participated in this study. Personalized free Achilles tendon moment arm and force-strain curve were obtained from imaging data and used in conjunction with motion capture and surface electromyography to estimate free Achilles tendon strain using electromyogram-informed neuromusculoskeletal modeling. There was a strong correspondence between Achilles tendon force estimates from the present study and experimental data reported in the literature (R2 > 0.85). The average tendon strain was highest for maximal hop landing (8.8 ± 1.6%), lowest for walking at 1.4 m/s (3.1 ± 0.8%), and increased with locomotor speed during running (run 3.0 m/s: 6.5 ± 1.6%; run 5.0 m/s: 7.9 ± 1.7%) and during heel rise exercise with added mass (BW: 5.8 ± 1.3%; 1.2 BW: 6.9 ± 1.7%). The peak tendon strain was highest during running (5 m/s: 13.7 ± 2.5%) and lowest during walking (1.4 m/s: 7 ± 1.8%). Overall findings provide a preliminary evidence base for exercise selection to maximize anabolic tendon remodeling during training and rehabilitation of the Achilles tendon.NEW & NOTEWORTHY Our work combines medical imaging and electromyogram-informed neuromusculoskeletal modeling data to estimate free Achilles tendon strain during selected rehabilitation, locomotor, jumping, and landing tasks in trained middle-distance runners. These data may potentially be used to inform Achilles tendon training and rehabilitation to maximize anabolic tendon remodeling.

Clinicians' perceived value and demographic factors that predict the utilisation of patient reported outcome measures for low back pain amongst chiropractors in Australia.

BACKGROUND: Factors that influence utilisation rates of patient reported outcome measures (PROMs) for low back pain (LBP) within the chiropractic profession of Australia are currently unknown. This study aimed to examine whether factors, including age, sex, experience level, clinical title (principal vs associate), or a clinicians' perceived value of PROMs, are predictive of the frequency and/or type of PROMs used by chiropractors in the management of LBP. METHODS: A cross sectional online survey was distributed to members of the Chiropractic Association of Australia (CAA now known as Australian Chiropractors Association-ACA) and Chiropractic Australia (CA). 3,014 CAA members and 930 CA members were invited to participate totaling 3,944, only respondents that were using PROMs were included in the analysis (n = 370). Ordinal logistic regression was used to examine associations between clinician demographics and perceived value of PROMs, and the frequency of pain, health, and functional patient reported outcome measure (PROM) usage by chiropractors. RESULTS: Principal chiropractors were more likely (Wald = 4.101, p = 0.04, OR = 1.4 (1.0-2.1)) than associate chiropractors to frequently use pain-related PROMs for the management of patients with LBP. The remaining demographic factors (age, sex, and experience level) were not associated with the frequency of PROM usage; nor were the perceived value clinicians place on PROMs in clinical practice. CONCLUSION: Principal chiropractors were more likely to frequently use pain-related PROMs for the management of patients with LBP when compared to associate chiropractors. Demographic factors, appear to have little influence on PROM usage. While chiropractors place high value on PROMs, these beliefs are not associated with increased frequency of PROM usage for the management of LBP.

Regional Variation in Muscle Echogenicity Is Related to Muscle Thickness in Young Children.

Quantitative ultrasound of muscle echogenicity may be influenced by the size of the muscle and, so, corrections may be required when comparing echogenicity between populations with different muscle size. This study examined the relationship between regional muscle echogenicity and geometry in young, typically developing children (n = 49, mean ± standard deviation [SD] age = 70.8 ± 30.0 mo). Three-dimensional ultrasound was used to measure mean echo intensity (EI) and echo variation (EV), together with muscle thickness, cross-sectional area (CSA) and width, over the entire muscle length for the medial gastrocnemius (MG), rectus femoris (RF) and tibialis anterior muscles. Pearson's correlation coefficient (r) was used to assess the strength of the relationship between echogenicity and geometry using all images taken over the entire muscle length. There were moderate-strong correlations (r = 0.67-0.90) between EI and EV and thickness for each muscle, with the strongest correlations evident for the MG and RF. EI and EV were moderately correlated with muscle CSA and weakly correlated with muscle width. Normalisation of echogenicity to muscle thickness may help delineate between regions of contractile and non-contractile tissue and provide a useful measure of muscle echogenicity when comparing muscles of different cross-sectional dimensions. We recommend that researchers consider controlling for muscle size-dependent effects on echogenicity, by normalising EI and EV to muscle thickness, or including the latter as a covariate when comparing between groups.

Upper limb position affects pain-free grip strength in individuals with lateral elbow tendinopathy.

BACKGROUND AND PURPOSE: Pain-free grip (PFG) force is commonly used to monitor treatment outcomes in lateral elbow tendinopathy (LET); however, it is unclear whether changes in forearm and elbow position affect PFG force values. This study aims to examine the effect of elbow/shoulder and forearm position on non-normalised and normalised PFG force in individuals with unilateral LET. METHODS: A cohort study including 21 subjects with clinically diagnosed unilateral LET (13 females, mean [SD] age 50 [8] years) performed PFG force (symptomatic arm) and maximal grip (asymptomatic arm) tasks using four upper limb positions: (1) shoulder neutral, elbow flexed (90°), forearm pronated; (2) shoulder neutral, elbow flexed (90°), forearm neutral; (3) shoulder flexed (90°), elbow extended, forearm pronated; and (4) shoulder flexed (90°), elbow extended, forearm neutral. PFG force was normalised to the maximal grip of the asymptomatic side. Repeated-measures analyses of variance were used to compare non-normalised and PFG force normalised to maximal grip between positions. RESULTS: Both non-normalised and normalised PFG forces were greater in position 2 than position 1, position 3 and position 4 (elbow-by-forearm interaction non-normalised p = 0.002, normalised p = 0.004). There were no differences between positions 1, 3 and 4 for either non-normalised or normalised PFG strength. DISCUSSION: This study shows that PFG force was higher when performed with forearm neutral supination/pronation, elbow flexion and shoulder neutral than other tested positions, and irrespective of whether PFG force was normalised to the maximal grip force of the contralateral limb. This indicates that arm position should be standardised for comparison.