Interventions for improving mobility after hip fracture surgery in adults.

BACKGROUND: Improving mobility outcomes after hip fracture is key to recovery. Possible strategies include gait training, exercise and muscle stimulation. This is an update of a Cochrane Review last published in 2011. OBJECTIVES: To evaluate the effects (benefits and harms) of interventions aimed at improving mobility and physical functioning after hip fracture surgery in adults. SEARCH METHODS: We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register, the Cochrane Central Register of Controlled Trials, MEDLINE, Embase, CINAHL, trial registers and reference lists, to March 2021. SELECTION CRITERIA: All randomised or quasi-randomised trials assessing mobility strategies after hip fracture surgery. Eligible strategies aimed to improve mobility and included care programmes, exercise (gait, balance and functional training, resistance/strength training, endurance, flexibility, three-dimensional (3D) exercise and general physical activity) or muscle stimulation. Intervention was compared with usual care (in-hospital) or with usual care, no intervention, sham exercise or social visit (post-hospital). DATA COLLECTION AND ANALYSIS: Members of the review author team independently selected trials for inclusion, assessed risk of bias and extracted data. We used standard methodological procedures expected by Cochrane. We used the assessment time point closest to four months for in-hospital studies, and the time point closest to the end of the intervention for post-hospital studies. Critical outcomes were mobility, walking speed, functioning, health-related quality of life, mortality, adverse effects and return to living at pre-fracture residence. MAIN RESULTS: We included 40 randomised controlled trials (RCTs) with 4059 participants from 17 countries. On average, participants were 80 years old and 80% were women. The median number of study participants was 81 and all trials had unclear or high risk of bias for one or more domains. Most trials excluded people with cognitive impairment (70%), immobility and/or medical conditions affecting mobility (72%). In-hospital setting, mobility strategy versus control Eighteen trials (1433 participants) compared mobility strategies with control (usual care) in hospitals. Overall, such strategies may lead to a moderate, clinically-meaningful increase in mobility (standardised mean difference (SMD) 0.53, 95% confidence interval (CI) 0.10 to 0.96; 7 studies, 507 participants; low-certainty evidence) and a small, clinically meaningful improvement in walking speed (CI crosses zero so does not rule out a lack of effect (SMD 0.16, 95% CI -0.05 to 0.37; 6 studies, 360 participants; moderate-certainty evidence). Mobility strategies may make little or no difference to short-term (risk ratio (RR) 1.06, 95% CI 0.48 to 2.30; 6 studies, 489 participants; low-certainty evidence) or long-term mortality (RR 1.22, 95% CI 0.48 to 3.12; 2 studies, 133 participants; low-certainty evidence), adverse events measured by hospital re-admission (RR 0.70, 95% CI 0.44 to 1.11; 4 studies, 322 participants; low-certainty evidence), or return to pre-fracture residence (RR 1.07, 95% CI 0.73 to 1.56; 2 studies, 240 participants; low-certainty evidence). We are uncertain whether mobility strategies improve functioning or health-related quality of life as the certainty of evidence was very low. Gait, balance and functional training probably causes a moderate improvement in mobility (SMD 0.57, 95% CI 0.07 to 1.06; 6 studies, 463 participants; moderate-certainty evidence). There was little or no difference in effects on mobility for resistance training. No studies of other types of exercise or electrical stimulation reported mobility outcomes. Post-hospital setting, mobility strategy versus control Twenty-two trials (2626 participants) compared mobility strategies with control (usual care, no intervention, sham exercise or social visit) in the post-hospital setting. Mobility strategies lead to a small, clinically meaningful increase in mobility (SMD 0.32, 95% CI 0.11 to 0.54; 7 studies, 761 participants; high-certainty evidence) and a small, clinically meaningful improvement in walking speed compared to control (SMD 0.16, 95% CI 0.04 to 0.29; 14 studies, 1067 participants; high-certainty evidence). Mobility strategies lead to a small, non-clinically meaningful increase in functioning (SMD 0.23, 95% CI 0.10 to 0.36; 9 studies, 936 participants; high-certainty evidence), and probably lead to a slight increase in quality of life that may not be clinically meaningful (SMD 0.14, 95% CI -0.00 to 0.29; 10 studies, 785 participants; moderate-certainty evidence). Mobility strategies probably make little or no difference to short-term mortality (RR 1.01, 95% CI 0.49 to 2.06; 8 studies, 737 participants; moderate-certainty evidence). Mobility strategies may make little or no difference to long-term mortality (RR 0.73, 95% CI 0.39 to 1.37; 4 studies, 588 participants; low-certainty evidence) or adverse events measured by hospital re-admission (95% CI includes a large reduction and large increase, RR 0.86, 95% CI 0.52 to 1.42; 2 studies, 206 participants; low-certainty evidence). Training involving gait, balance and functional exercise leads to a small, clinically meaningful increase in mobility (SMD 0.20, 95% CI 0.05 to 0.36; 5 studies, 621 participants; high-certainty evidence), while training classified as being primarily resistance or strength exercise may lead to a clinically meaningful increase in mobility measured using distance walked in six minutes (mean difference (MD) 55.65, 95% CI 28.58 to 82.72; 3 studies, 198 participants; low-certainty evidence). Training involving multiple intervention components probably leads to a substantial, clinically meaningful increase in mobility (SMD 0.94, 95% CI 0.53 to 1.34; 2 studies, 104 participants; moderate-certainty evidence). We are uncertain of the effect of aerobic training on mobility (very low-certainty evidence). No studies of other types of exercise or electrical stimulation reported mobility outcomes. AUTHORS' CONCLUSIONS: Interventions targeting improvement in mobility after hip fracture may cause clinically meaningful improvement in mobility and walking speed in hospital and post-hospital settings, compared with conventional care. Interventions that include training of gait, balance and functional tasks are particularly effective. There was little or no between-group difference in the number of adverse events reported. Future trials should include long-term follow-up and economic outcomes, determine the relative impact of different types of exercise and establish effectiveness in emerging economies.

Involuntary hamstring muscle activity reduces passive hip range of motion during the straight leg raise test: a stimulation study in healthy people.

BACKGROUND: Involuntary hamstring muscle activity is present in some people during the straight leg raise test, but it is not known to what extent involuntary muscle activity limits passive joint range of motion. This study aimed to determine whether small amounts of involuntary hamstring activity limit passive hip range of motion during the straight leg raise test in healthy people. METHODS: Thirty healthy subjects were recruited from The University of Sydney. As the hamstring muscles were continuously stimulated to generate 0, 2.5, 5, 7.5 and 10% of knee flexion maximal voluntary contraction force, an investigator blinded to the amount of stimulation performed a straight leg raise test by passively raising the tested leg while keeping the knee extended. The test was stopped when the knee started to flex, at which point hip range of motion was recorded. RESULTS: On average, passive hip range of motion decreased by 0.6° for every 1% increase in knee flexion force caused by muscle activation (95% CI 0.3 to 0.9°, p = 0.0012). Subjects were instructed to fully relax when the straight leg raise test was performed, but a small amount of involuntary muscle activity (median 2.4% of maximal activation) was present during the trial without stimulation. CONCLUSIONS: Small amounts of involuntary hamstring muscles activity reduce passive hip range of motion during the straight leg raise test in healthy people. TRIAL REGISTRATION: The protocol for this study was registered with the Open Science Framework, reference: https://osf.io/fejpf/ . Registered 9 March 2017.

Tension-referenced measures of gastrocnemius slack length and stiffness in Parkinson's disease.

BACKGROUND: It is not known how passive muscle length and stiffness contribute to rigidity in Parkinson's disease. The objective of this study was to compare passive gastrocnemius muscle-tendon slack length and stiffness at known tension in Parkinson's disease subjects with ankle rigidity and in able-bodied people. METHODS: Passive ankle torque-angle curves were obtained from 15 Parkinson's disease subjects with rigidity and 15 control subjects. Torque-angle data were used to derive passive gastrocnemius length-tension data and calculate slack length and stiffness of the gastrocnemius muscle. Between-group comparisons were made with linear models. RESULTS: Gastrocnemius muscle-tendon slack lengths (adjusted between-group difference, 0.01 m; 95% CI, -0.02 to 0.04 m; P = 0.37) and stiffness (adjusted between-group difference, 15.7 m-1 ; 95% CI, -8.5 to 39.9 m-1 ; P = 0.19) were not significantly different between groups. CONCLUSIONS: Parkinson's disease subjects with ankle rigidity did not have significantly shorter or stiffer gastrocnemius muscles compared with control subjects. © 2016 International Parkinson and Movement Disorder Society.

Structured exercise improves mobility after hip fracture: a meta-analysis with meta-regression.

OBJECTIVES: To determine the effect of structured exercise on overall mobility in people after hip fracture. To explore associations between trial-level characteristics and overall mobility. DESIGN: Systematic review, meta-analysis and meta-regression. DATA SOURCES: MEDLINE, EMBASE, CINAHL, the Cochrane Central Register of Controlled Trials, the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register and the Physiotherapy Evidence Database to May 2014. STUDY ELIGIBILITY CRITERIA, PARTICIPANTS AND INTERVENTIONS: Randomised controlled trials of structured exercise, which aimed to improve mobility compared with a control intervention in adult participants after surgery for hip fracture were included. DATA EXTRACTION AND SYNTHESIS: Data were extracted by one investigator and checked by an independent investigator. Standardised mean differences (SMD) of overall mobility were meta-analysed using random effects models. Random effects meta-regression was used to explore associations between trial-level characteristics and overall mobility. RESULTS: 13 trials included in the meta-analysis involved 1903 participants. The pooled Hedges' g SMD for overall mobility was 0.35 (95% CI 0.12 to 0.58, p=0.002) in favour of the intervention. Meta-regression showed greater treatment effects in trials that included progressive resistance exercise (change in SMD=0.58, 95% CI 0.17 to 0.98, p=0.008, adjusted R2=60%) and delivered interventions in settings other than hospital alone (change in SMD=0.50, 95% CI 0.08 to 0.93, p=0.024, adjusted R2=49%). CONCLUSIONS AND IMPLICATIONS: Structured exercise produced small improvements on overall mobility after hip fracture. Interventions that included progressive resistance training and were delivered in other settings were more effective, although the latter may have been confounded by duration of interventions.

Is ankle contracture after stroke due to abnormal intermuscular force transmission?

Contracture after stroke could be due to abnormal mechanical interactions between muscles. This study examined if ankle plantarflexor muscle contracture after stroke is due to abnormal force transmission between the gastrocnemius and soleus muscles. Muscle fascicle lengths were measured from ultrasound images of soleus muscles in five subjects with stroke and ankle contracture and six able-bodied subjects. Changes in soleus fascicle length or pennation during passive knee extension at fixed ankle angle were assumed to indicate intermuscular force transmission. Changes in soleus fascicle length or pennation were adjusted for changes in ankle motion. Subjects with stroke had significant ankle contracture. After adjustment for ankle motion, 9 of 11 subjects demonstrated small changes in soleus fascicle length with knee extension, suggestive of intermuscular force transmission. However, the small changes in fascicle length may have been artifacts caused by movement of the ultrasound transducers. There were no systematic differences in change in fascicle length (median between-group difference adjusting for ankle motion = -0.01, 95% CI -0.26-0.08 mm/degree of knee extension) or pennation (-0.05, 95% CI -0.15-0.07 degree/ degree of knee extension). This suggests ankle contractures after stroke were not due to abnormal (systematically increased or decreased) intermuscular force transmission between the gastrocnemius and soleus.

The effect of face-to-face versus online learning on student performance in anatomy: an observational study using a causal inference approach.

Introduction: This study aimed to estimate the causal effect of face-to-face learning on student performance in anatomy, compared to online learning, by analysing examination marks under a causal structure. Methods: We specified a causal graph to indicate how the mode of learning affected student performance. We sampled purposively to obtain end-semester examination marks of undergraduate and postgraduate students who learned using face-to-face (pre-COVID, 2019) or online modes (post-COVID, 2020). The analysis was informed by the causal graph. Marks were compared using linear regression, and sensitivity analyses were conducted to assess if effects were robust to unmeasured confounding. Results: On average, face-to-face learning improved student performance in the end-semester examination in undergraduate students (gain of mean 8.3%, 95% CI 3.3 to 13.4%; E-value 2.77, lower limit of 95% CI 1.80) but lowered performance in postgraduate students (loss of 8.1%, 95% CI 3.6 to 12.6%; E-value 2.89, lower limit of 95% CI 1.88), compared to online learning. Discussion: Under the assumed causal graph, we found that compared to online learning, face-to-face learning improved student performance in the end-semester examination in undergraduate students, but worsened student performance in postgraduate students. These findings suggest that different modes of learning may suit different types of students. Importantly, this is the first attempt to estimate causal effects of the mode of learning on student performance under a causal structure. This approach makes our assumptions transparent, informs data analysis, and is recommended when using observational data to make causal inferences.

Responsible research practices could be more strongly endorsed by Australian university codes of research conduct.

BACKGROUND: This study aimed to investigate how strongly Australian university codes of research conduct endorse responsible research practices. METHODS: Codes of research conduct from 25 Australian universities active in health and medical research were obtained from public websites, and audited against 19 questions to assess how strongly they (1) defined research integrity, research quality, and research misconduct, (2) required research to be approved by an appropriate ethics committee, (3) endorsed 9 responsible research practices, and (4) discouraged 5 questionable research practices. RESULTS: Overall, a median of 10 (IQR 9 to 12) of 19 practices covered in the questions were mentioned, weakly endorsed, or strongly endorsed. Five to 8 of 9 responsible research practices were mentioned, weakly, or strongly endorsed, and 3 questionable research practices were discouraged. Results are stratified by Group of Eight (n = 8) and other (n = 17) universities. Specifically, (1) 6 (75%) Group of Eight and 11 (65%) other codes of research conduct defined research integrity, 4 (50%) and 8 (47%) defined research quality, and 7 (88%) and 16 (94%) defined research misconduct. (2) All codes required ethics approval for human and animal research. (3) All codes required conflicts of interest to be declared, but there was variability in how strongly other research practices were endorsed. The most commonly endorsed practices were ensuring researcher training in research integrity [8 (100%) and 16 (94%)] and making study data publicly available [6 (75%) and 12 (71%)]. The least commonly endorsed practices were making analysis code publicly available [0 (0%) and 0 (0%)] and registering analysis protocols [0 (0%) and 1 (6%)]. (4) Most codes discouraged fabricating data [5 (63%) and 15 (88%)], selectively deleting or modifying data [5 (63%) and 15 (88%)], and selective reporting of results [3 (38%) and 15 (88%)]. No codes discouraged p-hacking or hypothesising after results are known. CONCLUSIONS: Responsible research practices could be more strongly endorsed by Australian university codes of research conduct. Our findings may not be generalisable to smaller universities, or those not active in health and medical research.

Encouraging responsible reporting practices in the Instructions to Authors of neuroscience and physiology journals: There is room to improve.

Journals can substantially influence the quality of research reports by including responsible reporting practices in their Instructions to Authors. We assessed the extent to which 100 journals in neuroscience and physiology required authors to report methods and results in a rigorous and transparent way. For each journal, Instructions to Authors and any referenced reporting guideline or checklist were downloaded from journal websites. Twenty-two questions were developed to assess how journal Instructions to Authors address fundamental aspects of rigor and transparency in five key reporting areas. Journal Instructions to Authors and all referenced external guidelines and checklists were audited against these 22 questions. Of the full sample of 100 Instructions to Authors, 34 did not reference any external reporting guideline or checklist. Reporting whether clinical trial protocols were pre-registered was required by 49 journals and encouraged by 7 others. Making data publicly available was encouraged by 64 journals; making (processing or statistical) code publicly available was encouraged by ∼30 of the journals. Other responsible reporting practices were mentioned by less than 20 of the journals. Journals can improve the quality of research reports by mandating, or at least encouraging, the responsible reporting practices highlighted here.

Poor statistical reporting, inadequate data presentation and spin persist despite Journal awareness and updated Information for Authors.

Sound reporting of research results is fundamental to good science. Unfortunately, poor reporting is common and does not improve with editorial educational strategies. We investigated whether publicly highlighting poor reporting at a journal can lead to improved reporting practices. We also investigated whether reporting practices that are required or strongly encouraged in journal Information for Authors are enforced by journal editors and staff. A 2016 audit highlighted poor reporting practices in the Journal of Neurophysiology. In August 2016 and 2018, the American Physiological Society updated the Information for Authors, which included the introduction of several required or strongly encouraged reporting practices. We audited Journal of Neurophysiology papers published in 2019 and 2020 (downloaded through the library of the University of New South Wales) on reporting items selected from the 2016 audit, the newly introduced reporting practices, and items from previous audits. Summary statistics (means, counts) were used to summarize audit results. In total, 580 papers were audited. Compared to results from the 2016 audit, several reporting practices remained unchanged or worsened. For example, 60% of papers erroneously reported standard errors of the mean, 23% of papers included undefined measures of variability, 40% of papers failed to define a statistical threshold for their tests, and when present, 64% of papers with p-values between 0.05 and 0.1 misinterpreted them as statistical trends. As for the newly introduced reporting practices, required practices were consistently adhered to by 34 to 37% of papers, while strongly encouraged practices were consistently adhered to by 9 to 26% of papers. Adherence to the other audited reporting practices was comparable to our previous audits. Publicly highlighting poor reporting practices did little to improve research reporting. Similarly, requiring or strongly encouraging reporting practices was only partly effective. Although the present audit focused on a single journal, this is likely not an isolated case. Stronger, more strategic measures are required to improve poor research reporting.

Upper Limb Function but Not Proprioception is Impaired in Essential Tremor: A Between-Groups Study and Causal Mediation Analysis.

Background: Essential tremor (ET) is characterized by abnormal oscillatory muscle activity and cerebellar involvement, factors that can lead to proprioceptive deficits, especially in active tasks. The present study aimed to quantify the severity of proprioceptive deficits in people with ET and estimate how these contribute to functional impairments. Methods: Upper limb sensory, proprioceptive and motor function was assessed inindividuals with ET (n = 20) and healthy individuals (n = 22). To measure proprioceptive ability, participants discriminated the width of grasped objects and the weight of objects liftedwith the wrist extensors. Causal mediation analysis was used to estimate the extentthat impairments in upper limb function in ET was mediated by proprioceptive ability. Results: Participants with ET had impaired upper limb function in all outcomes, and had greater postural and kinetic tremor. There were no differences between groups in proprioceptive discrimination of width (between-group mean difference [95% CI]: 0.32 mm [-0.23 to 0.87 mm]) or weight (-1.12 g [-7.31 to 5.07 g]). Causal mediation analysis showed the effect of ET on upper limb function was not mediated by proprioceptive ability. Conclusions: Upper limb function but not proprioception was impaired in ET. The effect of ET on motor function was not mediated by proprioception. These results indicate that the central nervous system of people with ET is able to accommodate mild to moderate tremor in active proprioceptive tasks that rely primarily on afferent signals from muscle spindles.

Passive mechanical properties of the gastrocnemius after spinal cord injury.

INTRODUCTION: In this study we compared passive mechanical properties of gastrocnemius muscle-tendon units, muscle fascicles, and tendons in control subjects and people with ankle contractures after spinal cord injury. METHODS: Passive gastrocnemius length-tension curves were derived from passive ankle torque-angle data obtained from 20 spinal cord injured subjects with ankle contractures and 30 control subjects. Ultrasound images of muscle fascicles were used to partition length-tension curves into fascicular and tendinous components. RESULTS: Spinal cord injured subjects had stiffer gastrocnemius muscle-tendon units (stiffness index: 74.8 ± 27.0 m(-1) ) than control subjects (54.4 ± 17.7 m(-1) ) (P = 0.004). Muscle-tendon slack lengths, as well as slack lengths and changes in length of fascicles and tendons, were similar in the two groups. CONCLUSIONS: People with ankle contractures after spinal cord injury have stiff gastrocnemius muscle-tendon units. It is not clear whether this reflects changes in properties of muscle fascicles or tendons.

Passive mechanical properties of gastrocnemius muscles of people with ankle contracture after stroke.

OBJECTIVE: To investigate the mechanisms of contracture after stroke by comparing passive mechanical properties of gastrocnemius muscle-tendon units, muscle fascicles, and tendons in people with ankle contracture after stroke with control participants. DESIGN: Cross-sectional study. SETTING: Laboratory in a research institution. PARTICIPANTS: A convenience sample of people with ankle contracture after stroke (n=20) and able-bodied control subjects (n=30). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Stiffness and lengths of gastrocnemius muscle-tendon units, lengths of muscle fascicles, and tendons at specific tensions. RESULTS: At a tension of 100N, the gastrocnemius muscle-tendon unit was significantly shorter in participants with stroke (mean, 436mm) than in able-bodied control participants (mean, 444mm; difference, 8mm; 95% confidence interval [CI], 0.2-15mm; P=.04). Muscle fascicles were also shorter in the stroke group (mean, 44mm) than in the control group (mean, 50mm; difference, 6mm; 95% CI, 1-12mm; P=.03). There were no significant differences between groups in the mean stiffness or length of the muscle-tendon units and fascicles at low tension, or in the mean length of the tendons at any tension. CONCLUSIONS: People with ankle contracture after stroke have shorter gastrocnemius muscle-tendon units and muscle fascicles than control participants at high tension. This difference is not apparent at low tension.

Muscle electromyographic activity normalized to maximal muscle activity, not to Mmax, better represents voluntary activation.

In human applied physiology studies, the amplitude of recorded muscle electromyographic activity (EMG) is often normalized to maximal EMG recorded during a maximal voluntary contraction. When maximal contractions cannot be reliably obtained (e.g. in people with muscle paralysis, anterior cruciate ligament injury, or arthritis), EMG is sometimes normalized to the maximal compound muscle action potiential evoked by stimulation, the Mmax. However, it is not known how these two methods of normalization affect the conclusions and comparability of studies. To address this limitation, we investigated the relationship between voluntary muscle activation and EMG normalized either to maximal EMG or to Mmax. Twenty-five able-bodied adults performed voluntary isometric ankle plantarflexion contractions to a range of percentages of maximal voluntary torque. Ankle torque, plantarflexor muscle EMG, and voluntary muscle activation measured by twitch interpolation were recorded. EMG recorded at each contraction intensity was normalized to maximal EMG or to Mmax for each plantarflexor muscle, and the relationship between the two normalization approaches quantified. A slope >1 indicated EMG amplitude normalized to maximal EMG (vertical axis) was greater than EMG normalized to Mmax (horizontal axis). Mean estimates of the slopes were large and had moderate precision: soleus 8.7 (95% CI 6.9 to 11.0), medial gastrocnemius 13.4 (10.5 to 17.0), lateral gastrocnemius 11.4 (9.4 to 14.0). This indicates EMG normalized to Mmax is approximately eleven times smaller than EMG normalized to maximal EMG. Normalization to maximal EMG gave closer approximations to the level of voluntary muscle activation assessed by twitch interpolation.

Eccentric exercise improves joint flexibility in adults: A systematic review update and meta-analysis.

BACKGROUND: Eccentric exercise is thought to improve joint flexibility, but the size of the effect is not known. We aimed to quantify the overall effect of eccentric exercise on joint flexibility in adults. DESIGN: Systematic review, meta-analysis. DATA SOURCES: AMED, CINAHL, MEDLINE, EMBASE, SportDiscus. PARTICIPANTS: Adults. INTERVENTION: Eccentric exercise compared to no intervention or to a different intervention. OUTCOME MEASURES: Joint range of motion or muscle fascicle length. DATA EXTRACTION AND SYNTHESIS: Descriptive data of included trials and estimates of effect sizes were extracted. Standardised mean differences (SMD) of range of motion or fascicle length outcomes were meta-analysed using random effects models. Overall quality of evidence was assessed using the GRADE scale. RESULTS: 32 trials (1122 participants, 108 lost to follow-up) were included in the systematic review. The mean (SD) PEDro score was 5.2 (1.3). Four trials reported insufficient data for meta-analysis. Data from 27 trials (911 participants, 82 lost to follow-up) were meta-analysed. Eccentric exercise improved joint flexibility in adults (pooled random effects Hedges' g SMD = 0.54, 95% CI 0.34 to 0.74). The true effect size is different across studies and 50% of the variance in observed effects is estimated to reflect variance in true effects rather than sampling error (I2 = 50%, Q = 67.6, d.f. = 34, p = 0.001). Overall quality of evidence ranged from 'low' to 'high'. CONCLUSION: Eccentric exercise improves joint flexibility in adults. The overall standardised mean effect of eccentric exercise was moderately large, and the narrow width of the 95% confidence interval indicates the effect was estimated with good precision. REGISTRATION: Open Science Foundation (https://osf.io/mkdqr); PROSPERO registration CRD42020151303.

In vivo passive mechanical behaviour of muscle fascicles and tendons in human gastrocnemius muscle-tendon units.

Ultrasound imaging was used to measure the length of muscle fascicles in human gastrocnemius muscles while the muscle was passively lengthened and shortened by moving the ankle. In some subjects the muscle belly 'buckled' at short lengths. When the gastrocnemius muscle-tendon unit was passively lengthened from its shortest in vivo length by dorsiflexing the ankle, increases in muscle-tendon length were not initially accompanied by increases in muscle fascicle lengths (fascicle length remained constant), indicating muscle fascicles were slack at short muscle-tendon lengths. The muscle-tendon length at which slack is taken up differs among fascicles: some fascicles begin to lengthen at very short muscle-tendon lengths whereas other fascicles remain slack over a large range of muscle-tendon lengths. This suggests muscle fascicles are progressively 'recruited' and contribute sequentially to muscle-tendon stiffness during passive lengthening of the muscle-tendon unit. Even above their slack lengths muscle fascicles contribute only a small part (<~30%) of the total change in muscle-tendon length. The contribution of muscle fascicles to muscle-tendon length increases with muscle length. The novelty of this work is that it reveals a previously unrecognised phenomenon (buckling at short lengths), posits a new mechanism of passive mechanical properties of muscle (recruitment of muscle fascicles), and confirms with high-resolution measurements that the passive compliance of human gastrocnemius muscle-tendon units is due largely to the tendon. It would be interesting to investigate if adaptations of passive properties of muscles are associated with changes in the distribution of muscle lengths at which fascicles fall slack.

Acute experimentally-induced pain replicates the distribution but not the quality or behaviour of clinical appendicular musculoskeletal pain. A systematic review.

OBJECTIVES: Experimental pain is a commonly used method to draw conclusions about the motor response to clinical musculoskeletal pain. A systematic review was performed to determine if current models of acute experimental pain validly replicate the clinical experience of appendicular musculoskeletal pain with respect to the distribution and quality of pain and the pain response to provocation testing. METHODS: A structured search of Medline, Scopus and Embase databases was conducted from database inception to August 2020 using the following key terms: "experimental muscle pain" OR "experimental pain" OR "pain induced" OR "induced pain" OR "muscle hyperalgesia" OR ("Pain model" AND "muscle"). Studies in English were included if investigators induced experimental musculoskeletal pain into a limb (including the sacroiliac joint) in humans, and if they measured and reported the distribution of pain, quality of pain or response to a provocation manoeuvre performed passively or actively. Studies were excluded if they involved prolonged or delayed experimental pain, if temporomandibular, orofacial, lumbar, thoracic or cervical spine pain were investigated, if a full text of the study was not available or if they were systematic reviews. Two investigators independently screened each title and abstract and each full text paper to determine inclusion in the review. Disagreements were resolved by consensus with a third investigator. RESULTS: Data from 57 experimental pain studies were included in this review. Forty-six of these studies reported pain distribution, 41 reported pain quality and six detailed the pain response to provocation testing. Hypertonic saline injection was the most common mechanism used to induce pain with 43 studies employing this method. The next most common methods were capsaicin injection (5 studies) and electrical stimulation, injection of acidic solution and ischaemia with three studies each. The distribution of experimental pain was similar to the area of pain reported in clinical appendicular musculoskeletal conditions. The quality of appendicular musculoskeletal pain was not replicated with the affective component of the McGill Pain Questionnaire consistently lower than that typically reported by musculoskeletal pain patients. The response to provocation testing was rarely investigated following experimental pain induction. Based on the limited available data, the increase in pain experienced in clinical populations during provocative maneuvers was not consistently replicated. CONCLUSIONS: Current acute experimental pain models replicate the distribution but not the quality of chronic clinical appendicular musculoskeletal pain. Limited evidence also indicates that experimentally induced acute pain does not consistently increase with tests known to provoke pain in patients with appendicular musculoskeletal pain. The results of this review question the validity of conclusions drawn from acute experimental pain studies regarding changes in muscle behaviour in response to pain in the clinical setting.

Strengthening the incentives for responsible research practices in Australian health and medical research funding.

BACKGROUND: Australian health and medical research funders support substantial research efforts, and incentives within grant funding schemes influence researcher behaviour. We aimed to determine to what extent Australian health and medical funders incentivise responsible research practices. METHODS: We conducted an audit of instructions from research grant and fellowship schemes. Eight national research grants and fellowships were purposively sampled to select schemes that awarded the largest amount of funds. The funding scheme instructions were assessed against 9 criteria to determine to what extent they incentivised these responsible research and reporting practices: (1) publicly register study protocols before starting data collection, (2) register analysis protocols before starting data analysis, (3) make study data openly available, (4) make analysis code openly available, (5) make research materials openly available, (6) discourage use of publication metrics, (7) conduct quality research (e.g. adhere to reporting guidelines), (8) collaborate with a statistician, and (9) adhere to other responsible research practices. Each criterion was answered using one of the following responses: "Instructed", "Encouraged", or "No mention". RESULTS: Across the 8 schemes from 5 funders, applicants were instructed or encouraged to address a median of 4 (range 0 to 5) of the 9 criteria. Three criteria received no mention in any scheme (register analysis protocols, make analysis code open, collaborate with a statistician). Importantly, most incentives did not seem strong as applicants were only instructed to register study protocols, discourage use of publication metrics and conduct quality research. Other criteria were encouraged but were not required. CONCLUSIONS: Funders could strengthen the incentives for responsible research practices by requiring grant and fellowship applicants to implement these practices in their proposals. Administering institutions could be required to implement these practices to be eligible for funding. Strongly rewarding researchers for implementing robust research practices could lead to sustained improvements in the quality of health and medical research.