Imperial College London

Anthony M J Bull .......... .... Professor of Musculoskeletal Mechanics

Faculty of EngineeringDepartment of Bioengineering

Professor of Musculoskeletal Mechanics



+44 (0)20 7594 5186a.bull Website




Mrs Angela Glyes +44 (0)20 7594 9794




B217Bessemer BuildingSouth Kensington Campus





Publication Type

319 results found

Weinberg PD, Schroter RC, Parker KH, Bull AMJ, Miller TE, Moore JEet al., 2022, In Memoriam: Colin Caro 1925-2022., J Biomech Eng, Vol: 144

Journal article

Ashworth E, Baxter D, Gibb I, Wilson M, Bull Aet al., 2022, Injuries underbody blast fatalities: identification of five distinct mechanisms of head injury, Journal of Neurotrauma, ISSN: 0897-7151

Previous research has shown that injuries to the head and neck were prevalent in 73%of all mounted fatalities of underbody blast. The mechanisms that cause such injuries to thecentral nervous system are not yet known. The aim of this study was to identify the head andspinal injuries in fatalities due to underbody blast and then develop hypotheses on the causativemechanisms.All UK military fatalities from underbody blast who suffered a head injury from 2007-2013 in the Iraq and Afghanistan conflicts were identified retrospectively. Post-mortem CTs(PMCTs) were interrogated for injuries to the head, neck and spine. All injuries weredocumented and classified using a radiology classification. Chi-squared and Fisher’s Exacttests were used to show a relationship between variables and form a hypothesis for injurymechanisms.There were 50 fatalities from underbody blast with an associated head injury. Of these,46 had complete CTPMs available for analysis. Chi-squared and Fisher’s exact showed arelationship between lateral ventricle blood and injuries to the abdomen and thorax.Five partially overlapping injury constellations were identified:1. multiple level spinal injury with skull fracture and brainstem injury;2. perimesencephalic haemorrhage3. spinal and brainstem injury;4. parenchymal contusions with injury to C0-C1; and5. an eggshell pattern of fractures from direct impact.These injury constellations can now be used to propose injury mechanisms in order todevelop mitigation strategies or clinical treatments.

Journal article

Sargent W, Bull AMJ, Gibb I, 2022, Focused Assessment with Sonography in Trauma (FAST) performance in paediatric conflict injury, CLINICAL RADIOLOGY, Vol: 77, Pages: 529-534, ISSN: 0009-9260

Journal article

Dyball D, Bennett AN, Schofield S, Cullinan P, Boos CJ, Bull AMJ, Wessely S, Stevelink SAM, Fear NT, ADVANCE studyet al., 2022, Mental health outcomes of male UK military personnel deployed to Afghanistan and the role of combat injury: analysis of baseline data from the ADVANCE cohort study., Lancet Psychiatry, Vol: 9, Pages: 547-554

BACKGROUND: The long-term psychosocial outcomes of UK armed forces personnel who sustained serious combat injuries during deployment to Afghanistan are largely unknown. We aimed to assess rates of probable post-traumatic stress disorder (PTSD), depression, anxiety, and mental health-associated multimorbidity in a representative sample of serving and ex-serving UK military personnel with combat injuries, compared with rates in a matched sample of uninjured personnel. METHODS: This analysis used baseline data from the ADVANCE cohort study, in which injured individuals were recruited from a sample of UK armed forces personnel who were deployed to Afghanistan and had physical combat injuries, according to records provided by the UK Ministry of Defence. Participants from the uninjured group were frequency-matched by age, rank, regiment, deployment, and role on deployment. Participants were recruited through postal, email, and telephone invitations. Participants completed a comprehensive health assessment, including physical health assessment and self-reported mental health measures (PTSD Checklist, Patient Health Questionnaire-9, and Generalised Anxiety Disorder-7). The mental health outcomes were rates of PTSD, depression, anxiety, and mental health-associated multimorbidity in the injured and uninjured groups. The ADVANCE study is ongoing and is registered with the ISRCTN registry, ISRCTN57285353. FINDINGS: 579 combat-injured participants (161 with amputation injuries and 418 with non-amputation injuries) and 565 uninjured participants were included in the analysis. Participants had a median age of 33 years (IQR 30-37 years) at the time of assessment. 90·3% identified as White and 9·7% were from all other ethnic groups. The rates of PTSD (16·9% [n=89] vs 10·5% [n=53]; adjusted odds ratio [AOR] 1·67 [95% CI 1·16-2·41], depression (23·6% [n=129] vs 16·8% [n=87]; AOR 1·46 [1·08-2·03]), anx

Journal article

Dyball D, Bennett A, Schofield S, Cullinan P, Boos C, Bull A, Wessely S, Stevelink S, Fear N, on behalf of the ADVANCE studyet al., 2022, Mental health outcomes of male UK military personnel deployed to Afghanistan and the role of combat-injury: The ADVANCE cohort study, The Lancet Psychiatry, ISSN: 2215-0366

Background: The long-term psychosocial outcomes of UK Armed Forces personnel who sustained serious combat-injuries during deployment to Afghanistan are largely unknown. This study hypothesised that the rates of probable Post Traumatic Stress Disorder (PTSD), depression, anxiety and mental health multimorbidity will be greater among a representative sample of ex-/serving military personnel with combat injuries compared to a matched sample of uninjured ex-/serving military personnel.Methods: 579 combat-injured and a comparison group of 565 uninjured male UK Armed Forces ex-/serving personnel, frequency-matched by age, rank, regiment, deployment, and role on deployment were included in this analysis. Participants had a median age of 33 (IQR 30, 37) at time of assessment. 90·3% identified as white and 9·7% were from all other ethnic groups. Participants completed a comprehensive health assessment including both physical health assessment and self-reported mental health measures.Results: The rates of PTSD (16·9% vs 10·5%; Adjusted Odds Ratio (AOR) 1·67 (95% Confidence Interval (CI) 1·16, 2·41), depression (23·6% vs 16·8%; AOR 1·46 (95%CI 1·08, 2·03), anxiety (20·8% vs 13·5%; AOR 1·56 (95%CI 1·13, 2·24) and mental health multimorbidity (15·3% vs 9·8%; AOR 1·62 (95%CI 1·12, 2·49) were greater in the injured versus uninjured group respectively. Minimal differences in odds of reporting any poor mental health outcome were noted between the amputation injury subgroup and the uninjured group, whereas up to double the odds were noted for the non-amputation injury subgroup.Interpretation: Serious physical combat-injuries are associated with poor mental health outcomes. However, type of injury influences this relationship. Regardless of injury, this cohort represents a group who present with greater rates of PTSD compared to the

Journal article

Boos C, Schofield S, Cullinan P, Dyball D, Fear N, Bull A, Pernet D, Bennett Aet al., 2022, Association between combat-related traumatic injury and cardiovascular risk, Heart, Vol: 108, Pages: 367-374, ISSN: 1355-6037

Objective The association between combat-related traumatic injury (CRTI) and cardiovascular risk is uncertain. This study aimed to investigate the association between CRTI and both metabolic syndrome (MetS) and arterial stiffness.Methods This was a prospective observational cohort study consisting of 579 male adult UK combat veterans (UK-Afghanistan War 2003–2014) with CRTI who were frequency-matched to 565 uninjured men by age, service, rank, regiment, deployment period and role-in-theatre. Measures included quantification of injury severity (New Injury Severity Score (NISS)), visceral fat area (dual-energy X-ray absorptiometry), arterial stiffness (heart rate-adjusted central augmentation index (cAIx) and pulse wave velocity (PWV)), fasting venous blood glucose, lipids and high-sensitivity C reactive protein (hs-CRP).Results Overall the participants were 34.1±5.4 years, with a mean (±SD) time from injury/deployment of 8.3±2.1 years. The prevalence of MetS (18.0% vs 11.8%; adjusted risk ratio 1.46, 95% CI 1.10 to 1.94, p<0.0001) and the mean cAIx (17.61%±8.79% vs 15.23%±8.19%, p<0.0001) were higher among the CRTI versus the uninjured group, respectively. Abdominal waist circumference, visceral fat area, triglycerides, estimated insulin resistance and hs-CRP levels were greater and physical activity and high-density lipoprotein-cholesterol lower with CRTI. There were no significant between-group differences in blood glucose, blood pressure or PWV. CRTI, injury severity (↑NISS), age, socioeconomic status (SEC) and physical activity were independently associated with both MetS and cAIx.Conclusions CRTI is associated with an increased prevalence of MetS and arterial stiffness, which are also influenced by age, injury severity, physical activity and SEC. The longitudinal impact of CRTI on clinical cardiovascular events needs further examination.

Journal article

Hazell GA, Pearce AP, Hepper AE, Bull AMJet al., 2022, Injury scoring systems for blast injuries: a narrative review, British Journal of Anaesthesia, Vol: 128, Pages: e127-e134, ISSN: 0007-0912

Injury scoring systems can be used for triaging, predicting morbidity and mortality, and prognosis in mass casualty incidents. Recent conflicts and civilian incidents have highlighted the unique nature of blast injuries, exposing deficiencies in current scoring systems. Here, we classify and describe deficiencies with current systems used for blast injury. Although current scoring systems highlight survival trends for populations, there are several major limitations. The reliable prediction of mortality on an individual basis is inaccurate. Other limitations include the saturation effect (where scoring systems are unable to discriminate between high injury score individuals), the effect of the overall injury burden, lack of precision in discriminating between mechanisms of injury, and a lack of data underpinning scoring system coefficients. Other factors influence outcomes, including the level of healthcare and the delay between injury and presentation. We recommend that a new score incorporates the severity of injuries with the mechanism of blast injury. This may include refined or additional codes, severity scores, or both, being added to the Abbreviated Injury Scale for high-frequency, blast-specific injuries; weighting for body regions associated with a higher risk for death; and blast-specific trauma coefficients. Finally, the saturation effect (maximum value) should be removed, which would enable the classification of more severe constellations of injury. An early accurate assessment of blast injury may improve management of mass casualty incidents.

Journal article

Urbanczyk CA, Bonfiglio A, McGregor AH, Bull AMJet al., 2021, Comparing optical and electromagnetic tracking systems to facilitate compatibility in sports kinematics data., International Biomechanics, Vol: 8, Pages: 75-84, ISSN: 2333-5432

Electromagnetic (EM) tracking has been used to quantify biomechanical parameters of the lower limb and lumbar spine during ergometer rowing to improve performance and reduce injury. Optical motion capture (OMC) is potentially better suited to measure comprehensive whole-body dynamics in rowing. This study compared accuracy and precision of EM and OMC displacements by simultaneously recording kinematics during rowing trials at low, middle, and high rates on an instrumented ergometer (n=12). Trajectories calculated from OMC and EM sensors attached to the pelvis, lumbar spine, and right leg were highly correlated, but EM tracking lagged behind ergometer and OMC tracking by approximately 6%, yielding large RMS errors. When this phase-lag was corrected by least squares minimization, agreement between systems improved. Both systems demonstrated an ability to adequately track large dynamic compound movements in the sagittal plane but struggled at times to precisely track small displacements and narrow angular ranges in medial/lateral and superior/inferior directions. An OMC based tracking methodology can obtain equivalence with a previously validated EM system, for spine and lower limb metrics. Improvements in speed and consistency of data acquisition with OMC are beneficial for dynamic motion studies. Compatibility ensures continuity by maintaining the ability to compare to prior work.

Journal article

Toderita D, Henson D, Klemt C, Ding Z, Bull AMJet al., 2021, An anatomical atlas-based scaling study for quantifying muscle and hip joint contact forces in above and through-knee amputees using validated musculoskeletal modelling, IEEE Transactions on Biomedical Engineering, Vol: 68, Pages: 3447-3456, ISSN: 0018-9294

Objective: Customisation of musculoskeletal modelling using magnetic resonance imaging (MRI) significantly improves the model accuracy, but the process is time consuming and computationally intensive. This study hypothesizes that linear scaling to a lower limb amputee model with anthropometric similarity can accurately predict muscle and joint reaction forces. Methods: An MRI-based anatomical atlas, comprising 18 trans-femoral and through-knee traumatic lower limb amputee models, is developed. Gait data, using a 10-camera motion capture system with two force plates, and surface electromyography (EMG) data were collected. Muscle and hip joint contact forces were quantified using musculoskeletal modelling. The predicted muscle activations from the subject-specific models were validated using EMG recordings. Anthropometry based multiple linear regression models, which minimize errors in force predictions, are presented. Results: All predictions showed excellent (error interval c=00.15), very good (c=0.150.30) or good (c=0.300.45) similarity to the recorded EMG data, demonstrating that the models accurately computed muscle activations. The primary predictors of discrepancies in force predictions were differences in pelvis width (p<0.001), body mass index (BMI, p<0.001) and stump length to pelvis width ratio (p<0.001) between the respective individual and underlying dataset. Conclusion: Linear scaling to a model with the most similar pelvis width, BMI and stump length to pelvis width ratio results in modelling outcomes with minimal errors. Significance: This study provides robust tools to perform accurate analyses of musculoskeletal mechanics for high-functioning lower limb military amputees, thus facilitating the further understanding and improvement of the amputee's function.

Journal article

Bull A, Hazell G, Pearce PA, Hepper Aet al., 2021, A critique of injury scoring systems when used for blastinjuries: a narrative review with recommendations forfuture work, British Journal of Anaesthesia, ISSN: 0007-0912

Injury scoring systems can be used for triaging, predicting morbidity and mortality, andprognosis. Recent conflicts and civilian incidents have highlighted the unique nature of blastinjuries, exposing deficiencies in current scoring systems. This review’s aim was to classifyand describe the issues with current systems when used in blast, identify deficiencies in theliterature, and propose scope for improvements of scoring systems.Strengths of current scoring systems include the ability to highlight survival trends forpopulations, thus allowing for assessment of medical advances. The review identified themajor limitations of current scoring systems as: the inability to accurately and reliably predictmortality outcomes for an individual patient; the saturation effect, where scoring systems areunable to discriminate between high injury score individuals; and underrepresentation of blastinjuries by omitting: systemic effects, the effect of the overall injury burden, lack of precisionin discriminating between injury mechanism, and lack of data underpinning scoring systemcoefficients. Other factors influence outcomes, including the level of healthcare, and the delaybetween injury and presentation. It is an open question whether these should be incorporatedin scoring systems.We recommend that a new score adapt the severity of injuries to the blast mechanism. Thismay include refined and additional codes, and severity scores, being added to the AIS systemfor high frequency blast-specific injuries; a weighting for body regions of higher risk of fatality;and blast specific trauma coefficients. Finally, the saturation effect (maximum value) beremoved enabling classification of more severe injury constellations

Journal article

Bin Abd Razak H, Chew D, Kazezian Z, Bull AMJet al., 2021, Autologous protein solution - a promising solution for osteoarthritis?, EFORT Open Reviews, Vol: 6, Pages: 716-726, ISSN: 2396-7544

Journal article

Henson DP, Edgar C, Ding Z, Sivapuratharasu B, Le Feuvre P, Finnegan ME, Quest R, McGregor AH, Bull AMJet al., 2021, Understanding lower limb muscle volume adaptations to amputation., Journal of Biomechanics, Vol: 125, Pages: 1-8, ISSN: 0021-9290

Amputation of a major limb, and the subsequent return to movement with a prosthesis, requires the development of compensatory strategies to account for the loss. Such strategies, over time, lead to regional muscle atrophy and hypertrophy through chronic under or overuse of muscles compared to uninjured individuals. The aim of this study was to quantify the lower limb muscle parameters of persons with transtibial and transfemoral amputations using high resolution MRI to ascertain muscle volume and to determine regression equations for predicting muscle volume using femur- and tibia-length, pelvic-width, height, and mass. Twelve persons with limb loss participated in this study and their data were compared to six matched control subjects. Subjects with unilateral transtibial amputation showed whole-limb muscle volume loss in the residual-limb, whereas minor volume changes in the intact limb were found, providing evidence for a compensation strategy that is dominated by the intact-limb. Subjects with bilateral-transfemoral amputations showed significant muscle volume increases in the short adductor muscles with an insertion not affected by the amputation, the hip flexors, and the gluteus medius, and significant volume decreases in the longer adductor muscles, rectus femoris, and hamstrings. This study presents a benchmark measure of muscle volume discrepancies in persons with limb-loss, and can be used to understand the compensation strategies of persons with limb-loss and the impact on muscle volume, thus enabling the development of optimised intervention protocols, conditioning therapies, surgical techniques, and prosthetic devices that promote and enhance functional capability within the population of persons with limb loss.

Journal article

Yeh C, Calder J, Antflick J, Bull A, Kedgley Aet al., 2021, Maximum dorsiflexion increases Achilles tendon force during exercise for midportion Achilles tendinopathy, Scandinavian Journal of Medicine and Science in Sports, Vol: 31, Pages: 1674-1682, ISSN: 0905-7188

Rehabilitation is an important treatment for non-insertional Achilles tendinopathy. To date, eccentric loading exercises (ECC) have been the predominant choice; however, mechanical evidence underlying their use remains unclear. Other protocols, such as heavy slow resistance loading (HSR), have shown comparable outcomes, but with less training time. This study aims to identify the effect of external loading and other variables that influence Achilles tendon (AT) force in ECC and HSR. Ground reaction force and kinematic data during ECC and HSR were collected from 18 healthy participants for four loading conditions. The moment arms of the AT were estimated from MRIs of each participant. AT force then was calculated using the ankle torque obtained from inverse dynamics. In the eccentric phase, the AT force was not larger than in the concentric phase in both ECC and HSR. Under the same external load, the force through the AT was larger in ECC with the knee bent than in HSR with the knee straight due to increased dorsiflexion angle of the ankle. Multivariate regression analysis showed that external load and maximum dorsiflexion angle were significant predictors of peak AT force in both standing and seated positions. Therefore, to increase the effectiveness of loading the AT, exercises should apply adequate external load and reach maximum dorsiflexion during the movement. Peak dorsiflexion angle affected the AT force in a standing position at twice the rate of a seated position, suggesting standing could prove more effective for the same external loading and peak dorsiflexion angle.

Journal article

Berthaume MA, Bull AMJ, 2021, Cyamella (a popliteal sesamoid bone) prevalence: a systematic review, meta-analysis, and proposed classification system, Clinical Anatomy, Vol: 34, Pages: 810-820, ISSN: 0897-3806

INTRODUCTION: The cyamella is a rare, generally asymptomatic, knee sesamoid bone located in the proximal tendon of the popliteal muscle. Only two studies have investigated cyamella presence/absence in humans, putting ossified prevalence rates at 0.57-1.8%. We aim to 1) determine cyamella prevalence in a Korean population, 2) examine coincident development of the cyamella and fabella, and 3) perform a systematic review and meta-analysis on the cyamella in humans. MATERIALS AND METHODS: Medical computed tomography scans of 106 individuals were reviewed. A systematic review and meta-analysis were performed following PRISMA guidelines. RESULTS: Cyamellae were found in 3/212 knees (1.4%), and presence/absence was uncorrelated to height, age, and sex. The cyamella was not found coincidentally with the fabella, although the statistical power was low. Our systematic review/meta-analysis revealed cyamellae were generally asymptomatic and ossification could occur at 14 years. Cyamellae were equally likely to be found in both sexes, knees, one or both knees, and there appeared to be no global variation in prevalence rates. Cyamellae were found in three distinct locations. CONCLUSIONS: There is little support for the role of intrinsic genetic and/or environmental factors in cyamella development in humans. However, the apparent phylogenetic signal in Primates suggests genetics plays a role in cyamella development. We propose a cyamella classification system based on cyamella location (Class I, popliteal sulcus; Class II, tibial condyle; Class III, fibular head) and hypothesize locations may correspond to distinct developmental pathways, and cyamella function may vary with location. This article is protected by copyright. All rights reserved.

Journal article

Farina D, Vujaklija I, Branemark R, Bull AMJ, Dietl H, Graimann B, Hargrove LJ, Hoffmann K-P, Huang HH, Ingvarsson T, Janusson HB, Kristjansson K, Kuiken T, Micera S, Stieglitz T, Sturma A, Tyler D, Weir RFF, Aszmann OCet al., 2021, Toward higher-performance bionic limbs for wider clinical use, Nature Biomedical Engineering, Pages: 1-13, ISSN: 2157-846X

Most prosthetic limbs can autonomously move with dexterity, yet they are not perceived by the user as belonging to their own body. Robotic limbs can convey information about the environment with higher precision than biological limbs, but their actual performance is substantially limited by current technologies for the interfacing of the robotic devices with the body and for transferring motor and sensory information bidirectionally between the prosthesis and the user. In this Perspective, we argue that direct skeletal attachment of bionic devices via osseointegration, the amplification of neural signals by targeted muscle innervation, improved prosthesis control via implanted muscle sensors and advanced algorithms, and the provision of sensory feedback by means of electrodes implanted in peripheral nerves, should all be leveraged towards the creation of a new generation of high-performance bionic limbs. These technologies have been clinically tested in humans, and alongside mechanical redesigns and adequate rehabilitation training should facilitate the wider clinical use of bionic limbs.

Journal article

Rebelo EA, Grigoriadis G, Carpanen D, Bull A, Masouros Set al., 2021, An experimentally validated finite element model of the lower limb to investigate the efficacy of blast mitigation systems, Frontiers in Bioengineering and Biotechnology, Vol: 9, ISSN: 2296-4185

Improvised explosive devices (IEDs) used in the battlefield cause damage to vehicles and their occupants. The injury burden to the casualties is significant. The biofidelity and practicality of current methods for assessing current protection to reduce the injury severity is limited. In this study, a finite-element (FE) model of the leg was developed and validated in relevant blast-loading conditions, and then used to quantify the level of protection offered by a combat boot. An FE model of the leg of a 35 years old male cadaver was developed. The cadaveric leg was tested physically in a seated posture using a traumatic injury simulator and the results used to calibrate the FE model. The calibrated model predicted hindfoot forces that were in good correlation (using the CORrelation and Analysis or CORA tool) with data from force sensors; the average correlation and analysis rating (according to ISO18571) was 0.842. The boundary conditions of the FE model were then changed to replicate pendulum tests conducted in previous studies which impacted the leg at velocities between 4 and 6.7 m/s. The FE model results of foot compression and peak force at the proximal tibia were within the experimental corridors reported in the studies. A combat boot was then incorporated into the validated computational model. Simulations were run across a range of blast-related loading conditions. The predicted proximal tibia forces and associated risk of injury indicated that the combat boot reduced the injury severity for low severity loading cases with higher times to peak velocity. The reduction in injury risk varied between 6 and 37% for calcaneal minor injuries, and 1 and 54% for calcaneal major injuries. No injury-risk reduction was found for high severity loading cases. The validated FE model of the leg developed here was able to quantify the protection offered by a combat boot to vehicle occupants across a range of blast-related loading conditions. It can now be used as a design an

Journal article

van Der Kruk E, Silverman AK, Reilly P, Bull AMJet al., 2021, Compensation due to age-related decline in sit-to-stand and sit-to-walk, JOURNAL OF BIOMECHANICS, Vol: 122, ISSN: 0021-9290

Journal article

van der Kruk E, Silverman AK, Koizia L, Reilly P, Fertleman M, Bull AMJet al., 2021, Age-related compensation: Neuromusculoskeletal capacity, reserve & movement objectives, JOURNAL OF BIOMECHANICS, Vol: 122, ISSN: 0021-9290

Journal article

Ding Z, Jarvis H, Bennett A, Baker R, Bull Aet al., 2021, Higher knee contact forces might underlie increased osteoarthritis rates in high functioning amputees: a pilot study, Journal of Orthopaedic Research, Vol: 39, Pages: 850-860, ISSN: 0736-0266

High functioning military transtibial amputees (TTAs) with well‐fitted state of the art prosthetics have gait that is indistinguishable from healthy individuals, yet they are more likely to develop knee osteoarthritis (OA) of their intact limbs. This contrasts with the information at the knees of the amputated limbs that have been shown to be at a significantly reduced risk of pain and OA. The hypothesis of this study is that biomechanics can explain the difference in knee OA risk. Eleven military unilateral TTAs and eleven matched healthy controls underwent gait analysis. Muscle forces and joint contact forces at the knee were quantified using musculoskeletal modeling, validated using electromyography measurements. Peak knee contact forces for the intact limbs on both the medial and lateral compartments were significantly greater than the healthy controls (P  ≤ .006). Additionally, the intact limbs had greater peak semimembranosus (P  = .001) and gastrocnemius (P  ≤ .001) muscle forces compared to the controls. This study has for the first time provided robust evidence of increased force on the non‐affected knees of high functioning TTAs that supports the mechanically based hypothesis to explain the documented higher risk of knee OA in this patient group. The results suggest several protentional strategies to mitigate knee OA of the intact limbs, which may include the improvements of the prosthetic foot control, socket design, and strengthening of the amputated muscles.

Journal article

Goodwin JE, Bull AMJ, 2021, Novel Assessment of Isometric Hip Extensor Function: Reliability, Joint Angle Sensitivity, and Concurrent Validity., J Strength Cond Res

ABSTRACT: Goodwin, JE and Bull, AMJ. Novel assessment of isometric hip extensor function: reliability, joint angle sensitivity, and concurrent validity. J Strength Cond Res XX(X): 000-000, 2021-Closed-chain hip extension function has not been well examined. The aim of this study was to examine the reliability, joint angle sensitivity, muscle recruitment, and concurrent validity of a force plate-based isometric hip extensor test (isometric hip thrust). All subjects were active men aged 19-29 years. In part 1, bilateral and unilateral hip extensor testing was completed on 4 occasions by 14 subjects to evaluate repeatability of force and torque measures. In part 2, joint angle sensitivity of force, torque, and surface electromyography was assessed by 10 subjects completing testing at 4 hip joint angles in a single test session. In part 3, concurrent validity of joint torque was assessed relative to standing and supine test positions on an isokinetic dynamometer, by 10 subjects in a single test session. The repeatability study found small changes in the mean from sessions 1-2 (mean standardized change d = 0.31) and close to no change in later sessions (mean d = 0.12). Typical error was predominantly low to moderate (mean 0.42), and intraclass correlation coefficient (ICC) was typically high (mean ICC = 0.87). The joint angle sensitivity study showed that increasing the hip flexion resulted in increases in peak extension force (p = 0.001) and gluteus maximus activation (p = 0.003) and a reduction in biceps femoris activation (p < 0.001). There was no change in torque (p = 0.585) and vastus lateralis activation (p = 0.482). The concurrent validity study found that torque was correlated with supine dynamometry (R2 = 0.555) but not with standing dynamometry (R2 = 0.193). In summary, the isometric hip thrust is repeatable, but benefits from familiarization. Force output and muscle recruitment are sensitive to joint position, providing an opportunity to assess different fu

Journal article

Kazezian Z, Yu X, Ramette M, Macdonald W, Bull Aet al., 2021, Development of a rodent high energy blast injury model for investigating conditions associated with traumatic amputations, Bone and Joint Research, Vol: 10, Pages: 1-8, ISSN: 2046-3758

In recent conflicts, most injuries to the extremities are due to blast resulting in a large number of lower limb amputations. These lead to heterotopic ossification (HO), phantom limb pain (PLP), and functional deficit. The mechanism of blast loading produces a combined facture and amputation. Therefore, to study these conditions, in vivo models that replicate this combined effect are required. The aim of this study is to develop a preclinical model of blast-induced lower limb amputation.

Journal article

Smith SHL, Coppack RJ, van den Bogert AJ, Bennett AN, Bull AMJet al., 2021, Review of musculoskeletal modelling in a clinical setting: Current use in rehabilitation design, surgical decision making and healthcare interventions, Clinical Biomechanics, Vol: 83, Pages: 1-9, ISSN: 0268-0033

BackgroundMusculoskeletal modelling is a common means by which to non-invasively analyse movement. Such models have largely been used to observe function in both healthy and patient populations. However, utility in a clinical environment is largely unknown. The aim of this review was to explore existing uses of musculoskeletal models as a clinical intervention, or decision-making, tool.MethodsA literature search was performed using PubMed and Scopus to find articles published since 2010 and relating to musculoskeletal modelling and joint and muscle forces.Findings4662 abstracts were found, of which 39 relevant articles were reviewed. Journal articles were categorised into 5 distinct groups: non-surgical treatment, orthoses assessment, surgical decision making, surgical intervention assessment and rehabilitation regime assessment. All reviewed articles were authored by collaborations between clinicians and engineers/modellers. Current uses included insight into the development of osteoarthritis, identifying candidates for hamstring lengthening surgery, and the assessment of exercise programmes to reduce joint damage.InterpretationThere is little evidence showing the use of musculoskeletal modelling as a tool for patient care, despite the ability to assess long-term joint loading and muscle overuse during functional activities, as well as clinical decision making to avoid unfavourable treatment outcomes. Continued collaboration between model developers should aim to create clinically-friendly models which can be used with minimal input and experience by healthcare professionals to determine surgical necessity and suitability for rehabilitation regimes, and in the assessment of orthotic devices.

Journal article

Kazezian Z, Bull AMJ, 2021, A review of the biomarkers and in vivo models for the diagnosis and treatment of heterotopic ossification following blast and trauma-induced injuries, Bone, Vol: 143, ISSN: 1873-2763

Heterotopic ossification (HO) is the process of de novo bone formation in non-osseous tissues. HO can occur following trauma and burns and over 60% of military personnel with blast-associated amputations develop HO. This rate is far higher than in other trauma-induced HO development. This suggests that the blast effect itself is a major contributing factor, but the pathway triggering HO following blast injury specifically is not yet fully identified. Also, because of the difficulty of studying the disease using clinical data, the only sources remain the relevant in vivo models. The aim of this paper is first to review the key biomarkers and signalling pathways identified in trauma and blast induced HO in order to summarize the molecular mechanisms underlying HO development, and second to review the blast injury in vivo models developed.The literature derived from trauma-induced HO suggests that inflammatory cytokines play a key role directing different progenitor cells to transform into an osteogenic class contributing to the development of the disease. This highlights the importance of identifying the downstream biomarkers under specific signalling pathways which might trigger similar stimuli in blast to those of trauma induced formation of ectopic bone in the tissues surrounding the site of the injury. The lack of information in the literature regarding the exact biomarkers leading to blast associated HO is hampering the design of specific therapeutics. The majority of existing blast injury in vivo models do not fully replicate the combat scenario in terms of blast, fracture and amputation; these three usually happen in one insult. Hence, this paper highlights the need to replicate the full effect of the blast in preclinical models to better understand the mechanism of blast induced HO development and to enable the design of a specific therapeutic to supress the formation of ectopic bone.

Journal article

Kazezian Z, Yu X, Ramette M, Macdonald W, Bull Aet al., 2020, Development of a blast injury model for investigating conditions associated with traumatic amputations, ORS 2021 Annual Meeting

INTRODUCTION: Most injuries in recent conflicts are due to blast, 70% of which are to the extremities resulting in a large number of lower limb amputations. Functional deficits due to blast induced amputation include difficulty in weight bearing and associated normal gait abnormali-ties. Significant complications following traumatic amputation are pain in the residual limb, and phantom limb pain. Heterotopic Ossification (HO) - ectopic bone formation in the soft tissues - is also highly prevalent (64%) among blast-related military amputations. The existing non-specific treatments include non-steroidal anti-inflammatory drugs (NSAID)s and low-dose radiation therapy which remain unsatisfactory leav-ing surgical bone excision the only possible curative treatment. While the prevention of HO in military amputees is the ultimate choice of treat-ment, it is yet to be identified, as the initial cause of triggering the disease is not understood. For this reason, and because studying amputation complications in humans is difficult, novel in vivo models need to be developed for further understanding of the disease mechanisms. There-fore, we hypothesised that developing a preclinical blast injury model in the hindlimb of rats which better represents the IED detonation in en-closed spaces could answer questions regarding the exact mechanism of HO and phantom limb pain. Current in vivo models exist, but none of these incorporate all blast features, that is, the blast, and the fracture in one insult. This research aims to develop a novel translational blast injury model in rats to better understand the mechanisms of phantom limb pain and HO.METHODS: This study was performed under institutional and departmental license from the Home Office UK. In line with the 3Rs principle, optimisation of the blast pressure was achieved using 34 male cadaveric Sprague-Dawley rats weighing between 285-481g to refine the experi-ments without using live animals to achieve a trans-tibial fracture at

Conference paper

Urbanczyk CA, Prinold JAI, Reilly P, Bull AMJet al., 2020, Avoiding high-risk rotator cuff loading: Muscle force during three pull-up techniques., Scandinavian Journal of Medicine and Science in Sports, Vol: 30, Pages: 2205-2214, ISSN: 0905-7188

Heavily loaded overhead training tasks, such as pull-ups are an effective strength training and rehabilitation exercise requiring high muscle forces maintained over a large range of motion. This study used experiments and computational modeling to examine loading patterns during three different pull-up variants and highlighted risks to vulnerable musculoskeletal structures. Optical motion tracking and a force platform captured kinematics and kinetics of 11 male subjects with no history of shoulder pathology, during performance of three pull-up variants-pronated front grip, pronated wide grip, and supinated reverse grip. UK National Shoulder model (UKNSM) simulated biomechanics of the shoulder girdle. Muscle forces and activation patterns were analyzed by repeated measures ANOVA with post-hoc comparisons. Motor group recruitment was similar across all pull-up techniques, with upper limb depression occurring secondary to torso elevation. Stress-time profiles show significant differences in individual muscle patterns among the three pull-up variants, with the most marked differences between wide grip and reverse grip. Comparing across techniques, latissimus dorsi was relatively more active in wide pull-ups (P < .01); front pull-ups favored activation of biceps brachii and brachialis (P < .02); reverse pull-ups displayed higher proportional rotator cuff activation (P < .01). Pull-ups promote stability of the shoulder girdle and activation of scapula stabilizers and performing pull-ups over their full range of motion is important as different techniques and phases emphasize different muscles. Shoulder rehabilitation and strength & conditioning programs should encourage incorporation of all three pull-up variants with systematic progression to provide greater global strengthening of the torso and upper limb musculature.

Journal article

Bennett AN, Dyball DM, Boos CJ, Fear NT, Schofield S, Bull AMJ, Cullinan P, ADVANCE Studyet al., 2020, Study protocol for a prospective, longitudinal cohort study investigating the medical and psychosocial outcomes of UK combat casualties from the Afghanistan war: the ADVANCE Study., BMJ Open, Vol: 10, Pages: 1-11, ISSN: 2044-6055

INTRODUCTION: The Afghanistan war (2003-2014) was a unique period in military medicine. Many service personnel survived injuries of a severity that would have been fatal at any other time in history; the long-term health outcomes of such injuries are unknown. The ArmeD SerVices TrAuma and RehabilitatioN OutComE (ADVANCE) study aims to determine the long-term effects on both medical and psychosocial health of servicemen surviving this severe combat related trauma. METHODS AND ANALYSIS: ADVANCE is a prospective cohort study. 1200 Afghanistan-deployed male UK military personnel and veterans will be recruited and will be studied at 0, 3, 6, 10, 15 and 20 years. Half are personnel who sustained combat trauma; a comparison group of the same size has been frequency matched based on deployment to Afghanistan, age, sex, service, rank and role. Participants undergo a series of physical health tests and questionnaires through which information is collected on cardiovascular disease (CVD), CVD risk factors, musculoskeletal disease, mental health, functional and social outcomes, quality of life, employment and mortality. ETHICS AND DISSEMINATION: The ADVANCE Study has approval from the Ministry of Defence Research Ethics Committee (protocol no:357/PPE/12) agreed 15 January 2013. Its results will be disseminated through manuscripts in clinical/academic journals and presentations at professional conferences, and through participant and stakeholder communications. TRIAL REGISTRATION NUMBER: The ADVANCE Study is registered at ISRCTN ID: ISRCTN57285353.

Journal article

Villatte G, van der Kruk E, Asim B, Zumstein M, Moor B, Emery R, Bull AMJ, Reilly Pet al., 2020, A biomechanical confirmation of the relationship between critical shoulder angle (CSA) and articular joint loading, Journal of Shoulder and Elbow Surgery, Vol: 29, Pages: 1967-1973, ISSN: 1058-2746

Background: The Critical Shoulder Angle (CSA) has been shown to be correlated with shoulder disease states. The biomechanical hypothesis to explain this correlation is that the CSA changes the shear and compressive forces on the shoulder. The objective of this study is to test this hypothesis by use of a validated computational shoulder model. Specifically, this study assesses the impact on glenohumeral biomechanics of modifying the CSA. Methods: An inverse dynamics three-dimensional musculoskeletal model of the shoulder was used to quantify muscle forces and glenohumeral joint forces. The CSA was changed by altering the attachment point of the middle deltoid into a normal CSA (33°), a reduced CSA of 28°, and an increased CSA of 38°. Subject-specific kinematics of slow and fast speed abduction in the scapular plane, and slow and fast forward flexion measured by a 3D motion capture system were used to quantify joint reaction shear and compressive forces.Results: Increasing the CSA results in increased superior-inferior forces (shearing forces; integrated over the range of motion; p<0.05). Reducing CSA results in increased latero-medial (compressive) forces for both the maximum and integrated sum of the forces over the whole motion; p<0.01).Discussion/Conclusion: Changes in the CSA modify glenohumeral joint biomechanics with increasing CSA producing higher shear forces that would contribute to rotator cuff overuse, whereas reducing the CSA results in higher compressive forces which contribute to joint wear.

Journal article

Foss L, Belli A, Brody D, Brookes M, Bull A, Craner M, Dunkley B, Evangelou N, Furlong P, Gibb I, Goldstone A, Green G, Hettiaratchy S, Hodgetts T, Lee R, Mistlin A, Nader K, Perl D, Reid A, Scadding J, Seri S, Sharp D, Sherwood D, Simms A, Sinclair A, Wessely S, Wilde E, Woods Det al., 2020, Setting a national consensus for managing mild and blast traumatic brain injury: post-meeting consensus report

A meeting was held on Wednesday 15 January 2020 to examine the current evidence for non-routine imaging and for neuroendocrine screening in the management of military personnel with brain injury and overlapping symptom domains. The Summit aimed to specifically address the relative utility of magnetoencephalography (MEG), diffusion tensor imaging (DTI) and susceptibility weighted imaging (SWI) in the UK context. This Consensus Report discusses points of consensus, points for further discussion/points of equipoise and recommendations that arose during, and following, the meeting.


Dimitrov H, Bull AMJ, Farina D, 2020, Real-time interface algorithm for ankle kinematics and stiffness from electromyographic signals, IEEE Transactions on Neural Systems and Rehabilitation Engineering, Vol: 28, Pages: 1416-1427, ISSN: 1534-4320

Shortcomings in capabilities of below-knee (transtibial) prostheses, compared to their biological counterparts, still cause medical complications and functional deficit to millions of amputees around the world. Although active (powered actuation) transtibial prostheses have the potential to bridge these gaps, the current control solutions limit their efficacy. Here we describe the development of a novel interface for two degrees-of-freedom position and stiffness control for below-knee amputees. The developed algorithm for the interface relies entirely on muscle electrical signals from the lower leg. The algorithm was tested for voluntary position and stiffness control in eight able-bodied and two transtibial amputees and for voluntary stiffness control with foot position estimation while walking in eight able-bodied and one transtibial amputee. The results of the voluntary control experiment demonstrated a promising target reaching success rate, higher for amputees compared to the able-bodied individuals (82.5% and 72.5% compared to 72.5% and 68.1% for the position and position and stiffness matching tasks respectively). Further, the algorithm could provide the means to control four stiffness levels during walking in both amputee and able-bodied individuals while providing estimates of foot kinematics (gait cycle cross-correlation >75% for the sagittal and >90% for the frontal plane and gait cycle root mean square error <7.5° in sagittal and <3° in frontal plane for able-bodied and amputee individuals across three walking speeds). The results from the two experiments demonstrate the feasibility of using this novel algorithm for online control of multiple degrees of freedom and of their stiffness in lower limb prostheses.

Journal article

Nolte D, Ko S-T, Bull AMJ, Kedgley AEet al., 2020, Reconstruction of the lower limb bones from digitised anatomical landmarks using statistical shape modelling, Gait & Posture, Vol: 77, Pages: 269-275, ISSN: 0966-6362

BackgroundBone shapes strongly influence force and moment predictions of kinematic and musculoskeletal models used in motion analysis. The precise determination of joint reference frames is essential for accurate predictions. Since clinical motion analysis typically does not include medical imaging, from which bone shapes may be obtained, scaling methods using reference subjects to create subject-specific bone geometries are widely used.Research questionThis study investigated if lower limb bone shape predictions from skin-based measurements, utilising an underlying statistical shape model (SSM) that corrects for soft tissue artefacts in digitisation, can be used to improve conventional linear scaling methods of bone geometries.MethodsSSMs created from 35 healthy adult femurs and tibiae/fibulae were used to reconstruct bone shapes by minimising the distance between anatomical landmarks on the models and those digitised in the motion laboratory or on medical images. Soft tissue artefacts were quantified from magnetic resonance images and then used to predict distances between landmarks digitised on the skin surface and bone. Reconstruction results were compared to linearly scaled models by measuring root mean squared distances to segmented surfaces, calculating differences of commonly used anatomical measures and the errors in the prediction of the hip joint centre.ResultsSSM reconstructed surface predictions from varying landmark sets from skin and bone landmarks were more accurate compared to linear scaling methods (2.60–2.95 mm vs. 3.66–3.87 mm median error; p < 0.05). No significant differences were found between SSM reconstructions from bony landmarks and SSM reconstructions from digitised landmarks obtained in the motion lab and therefore reconstructions using skin landmarks are as accurate as reconstructions from landmarks obtained from medical images.SignificanceThese results indicate that SSM reconstructions can be used to increase the accurac

Journal article

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