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.

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.

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.

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 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.

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.

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 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.

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.

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.

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.

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.

An Investigation of Maximal Strength of the Upper Limb Bilaterally in Individuals With Lateral Elbow Tendinopathy: A Systematic Review With Meta-Analysis.

OBJECTIVE: The aim of this study was to investigate whether there is evidence of bilateral upper limb strength deficits in individuals with unilateral lateral elbow tendinopathy (LET). METHODS: The electronic databases Medline via Ovid, PubMed, and Scopus were searched from inception to March 2020. Included studies encompassed maximal strength outcomes of any upper limb and appendicular musculature in individuals with LET and an asymptomatic comparator. Study quality was rated using a modified version of the Epidemiological Appraisal Instrument. Hedges g effect sizes (ES) and 95% CIs were calculated for comparisons of maximal strength in the LET group and an asymptomatic control group. Meta-analysis using a random-effects model was performed when possible. RESULTS: Fourteen studies were included. Quality appraisal resulted in a mean Epidemiological Appraisal Instrument score of 46% (SD = 10%). Meta-analysis revealed strength deficits in shoulder abduction (pooled ES = -0.37 [95% CI = -0.62 to -0.12]) and shoulder external rotation (pooled ES = -0.55 [95% CI = -0.83 to -0.28]) of the symptomatic limb compared with an asymptomatic control group. Meta-analysis also revealed maximal strength deficits in the upper trapezius (pooled ES = -0.26 [95% CI = -0.49 to -0.02]) of the asymptomatic limb compared with an asymptomatic control group. There was also consistent evidence for strength deficits in the serratus anterior, lower trapezius, and wrist extensor muscles and deficits in grip strength of the symptomatic limb as well as strength deficits in the wrist extensor muscles of the asymptomatic limb in individuals with unilateral LET. CONCLUSION: In individuals with LET, there were maximal strength deficits in shoulder abduction, shoulder external rotation, serratus anterior and lower trapezius muscles, and wrist extension, as well as deficits in grip strength of the symptomatic limb compared with an asymptomatic control group. In addition, there appeared to be strength deficits in the upper trapezius muscle, wrist extension, and metacarpophalangeal joint flexion and extension, as well as deficits in grip strength of the asymptomatic limb in individuals with LET compared with an asymptomatic control group. These results suggest bilateral strength deficits. IMPACT: These findings highlight the importance of a thorough physical examination and appropriate strengthening intervention for the upper limb with a focus on shoulder and scapular stabilizers, in addition to forearm muscles, in individuals with LET. LAY SUMMARY: In people with tennis elbow, widespread strength deficits, including weakness of the shoulder, forearm, and wrist muscles, may exist. Interestingly, some of these weaknesses appear on both the affected and the unaffected sides in people with tennis elbow. A physical therapist can help strengthen these areas.

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.

The Free Achilles Tendon Is Shorter, Stiffer, Has Larger Cross-Sectional Area and Longer T2* Relaxation Time in Trained Middle-Distance Runners Compared to Healthy Controls.

Tendon geometry and tissue properties are important determinants of tendon function and injury risk and are altered in response to ageing, disease, and physical activity levels. The purpose of this study was to compare free Achilles tendon geometry and mechanical properties between trained elite/sub-elite middle-distance runners and a healthy control group. Magnetic resonance imaging (MRI) was used to measure free Achilles tendon volume, length, average cross-sectional area (CSA), regional CSA, moment arm, and T2* relaxation time at rest, while freehand three-dimensional ultrasound (3DUS) was used to quantify free Achilles tendon mechanical stiffness, Young's modulus, and length normalised mechanical stiffness. The free Achilles tendon in trained runners was significantly shorter and the average and regional CSA (distal end) were significantly larger compared to the control group. Mechanical stiffness of the free Achilles tendon was also significantly higher in trained runners compared to controls, which was explained by the group differences in tendon CSA and length. T2* relaxation time was significantly longer in trained middle-distance runners when compared to healthy controls. There was no relationship between T2* relaxation time and Young's modulus. The longer T2* relaxation time in trained runners may be indicative of accumulated damage, disorganised collagen, and increased water content in the free Achilles tendon. A short free Achilles tendon with large CSA and higher mechanical stiffness may enable trained runners to rapidly transfer high muscle forces and possibly reduce the risk of tendon damage from mechanical fatigue.

Targeted Achilles Tendon Training and Rehabilitation Using Personalized and Real-Time Multiscale Models of the Neuromusculoskeletal System.

Musculoskeletal tissues, including tendons, are sensitive to their mechanical environment, with both excessive and insufficient loading resulting in reduced tissue strength. Tendons appear to be particularly sensitive to mechanical strain magnitude, and there appears to be an optimal range of tendon strain that results in the greatest positive tendon adaptation. At present, there are no tools that allow localized tendon strain to be measured or estimated in training or a clinical environment. In this paper, we first review the current literature regarding Achilles tendon adaptation, providing an overview of the individual technologies that so far have been used in isolation to understand in vivo Achilles tendon mechanics, including 3D tendon imaging, motion capture, personalized neuromusculoskeletal rigid body models, and finite element models. We then describe how these technologies can be integrated in a novel framework to provide real-time feedback of localized Achilles tendon strain during dynamic motor tasks. In a proof of concept application, Achilles tendon localized strains were calculated in real-time for a single subject during walking, single leg hopping, and eccentric heel drop. Data was processed at 250 Hz and streamed on a smartphone for visualization. Achilles tendon peak localized strains ranged from ∼3 to ∼11% for walking, ∼5 to ∼15% during single leg hop, and ∼2 to ∼9% during single eccentric leg heel drop, overall showing large strain variation within the tendon. Our integrated framework connects, across size scales, knowledge from isolated tendons and whole-body biomechanics, and offers a new approach to Achilles tendon rehabilitation and training. A key feature is personalization of model components, such as tendon geometry, material properties, muscle geometry, muscle-tendon paths, moment arms, muscle activation, and movement patterns, all of which have the potential to affect tendon strain estimates. Model personalization is important because tendon strain can differ substantially between individuals performing the same exercise due to inter-individual differences in these model components.

Evaluating the immediate effect of forearm and wrist orthoses on pain and function in individuals with lateral elbow tendinopathy: A systematic review.

BACKGROUND: Lateral elbow tendinopathy is associated with pain during gripping, with forearm/wrist orthoses prescribed for treatment. OBJECTIVES: To investigate the immediate effects of forearm and/or wrist orthoses on outcome measures of pain and function in individuals with lateral elbow tendinopathy. DESIGN: Systematic review METHODS: Four electronic databases were searched to identify randomised controlled trials reporting the immediate effects of forearm and/or wrist orthoses on pain and function in individuals with lateral elbow tendinopathy. The quality of evidence was rated from high to very low, using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) for the primary outcomes. Where possible, standardised mean difference (SMD) and 95% confidence intervals were calculated to compare post measures between forearm and/or wrist orthoses and control/placebo conditions. RESULTS: The search revealed 1965 studies, of which, seven randomised crossover trials were included. Using the GRADE approach there was low quality evidence revealing a significant decrease in pain during contraction (SMD range -0.65 to -0.83) with forearm orthoses compared to a control/placebo condition. Low quality evidence revealed improvements in pain-free grip strength with the use of a forearm orthosis (SMD range 0.24-0.38), but not maximal grip strength (SMD range 0.14-0.15). Low quality evidence revealed a static wrist orthosis did not improve pain-free grip strength (SMD -0.08) or maximal grip strength (SMD -0.22). CONCLUSION: There is low quality evidence that forearm orthoses can immediately reduce pain during contraction and improve pain-free grip strength but not maximal grip strength in individuals with lateral elbow tendinopathy.

Increasing level of neuromusculoskeletal model personalisation to investigate joint contact forces in cerebral palsy: A twin case study.

BACKGROUND: Cerebral palsy is a complex neuromuscular disorder that affects the sufferers in multiple different ways. Neuromusculoskeletal models are promising tools that can be used to plan patient-specific treatments for cerebral palsy. However, current neuromusculoskeletal models are typically scaled from generic adult templates that poorly represent paediatric populations. Furthermore, muscle activations are commonly computed via optimisation methods, which may not reproduce co-contraction observed in cerebral palsy. Alternatively, calibrated EMG-informed approaches within OpenSim can capture pathology-related muscle activation abnormalities, possibly enabling more feasible estimations of muscle and joint contact forces. METHODS: Two identical twin brothers, aged 13, one with unilateral cerebral palsy and the other typically developing, were enrolled in the study. Four neuromusculoskeletal models with increasing subject-specificity were built in OpenSim and CEINMS combining literature findings, experimental motion capture, EMG and MR data for both participants. The physiological and biomechanical validity of each model was assessed by quantifying its ability to track experimental joint moments and muscle excitations. FINDINGS: All developed models accurately tracked external joint moments; however EMG-informed models better tracked muscle excitations compared to neural solutions generated by static optimisation. Calibrating muscle-tendon unit parameters with EMG data allowed for more physiologically plausible joint contact forces estimates. Further scaling the maximal isometric force of muscles with MR-derived muscle volumes did not affect model predictions. INTERPRETATION: Given their ability to identify atypical joint contact forces profiles and accurately reproduce experimental data, calibrated EMG-informed models should be preferred over generic models using optimisation methods in informing the management of cerebral palsy.