261 results found
Azmi NL, Ding Z, Xu R, et al., 2018, Activation of biceps femoris long head reduces tibiofemoral anterior shear force and tibial internal rotation torque in healthy subjects., PLoS One, Vol: 13
The anterior cruciate ligament (ACL) provides resistance to tibial internal rotation torque and anterior shear at the knee. ACL deficiency results in knee instability. Optimisation of muscle contraction through functional electrical stimulation (FES) offers the prospect of mitigating the destabilising effects of ACL deficiency. The hypothesis of this study is that activation of the biceps femoris long head (BFLH) reduces the tibial internal rotation torque and the anterior shear force at the knee. Gait data of twelve healthy subjects were measured with and without the application of FES and taken as inputs to a computational musculoskeletal model. The model was used to investigate the optimum levels of BFLH activation during FES gait in reducing the anterior shear force to zero. This study found that FES significantly reduced the tibial internal rotation torque at the knee during the stance phase of gait (p = 0.0322) and the computational musculoskeletal modelling revealed that a mean BFLH activation of 20.8% (±8.4%) could reduce the anterior shear force to zero. At the time frame when the anterior shear force was zero, the internal rotation torque was reduced by 0.023 ± 0.0167 Nm/BW, with a mean 188% reduction across subjects (p = 0.0002). In conclusion, activation of the BFLH is able to reduce the tibial internal rotation torque and the anterior shear force at the knee in healthy control subjects. This should be tested on ACL deficient subject to consider its effect in mitigating instability due to ligament deficiency. In future clinical practice, activating the BFLH may be used to protect ACL reconstructions during post-operative rehabilitation, assist with residual instabilities post reconstruction, and reduce the need for ACL reconstruction surgery in some cases.
Britzman D, Igah I, Eftaxiopoulou T, et al., 2018, Tibial Osteotomy as a Mechanical Model of Primary Osteoarthritis in Rats., Sci Rep, Vol: 8
This study has presented the first purely biomechanical surgical model of osteoarthritis (OA) in rats, which could be more representative of the human primary disease than intra-articular techniques published previously. A surgical tibial osteotomy (TO) was used to induce degenerative cartilage changes in the medial knee of Sprague-Dawley rats. The presence of osteoarthritic changes in the medial knee compartment of the operated animals was evaluated histologically and through analysis of serum carboxy-terminal telepeptides of type II collagen (CTX-II). In-vivo biomechanical analyses were carried out using a musculoskeletal model of the rat hindlimb to evaluate the loading conditions in the knee pre and post-surgically. Qualitative and quantitative medial cartilage degeneration consistent with OA was found in the knees of the operated animals alongside elevated CTX-II levels and increased tibial compressive loading. The potential avoidance of joint inflammation post-surgically, the maintenance of internal joint biomechanics and the ability to quantify the alterations in joint loading should make this model of OA a better candidate for modeling primary forms of the disease in humans.
Bull A, Mayhew E, Reavley P, et al., 2018, Paediatric blast injury: challenges and priorities, The Lancet Child and Adolescent Health, Vol: 2, Pages: 310-311
Czasche MB, Goodwin JE, Bull AMJ, et al., 2018, Effects of an 8-week strength training intervention on tibiofemoral joint loading during landing: a cohort study., BMJ Open Sport Exerc Med, Vol: 4, ISSN: 2055-7647
Objectives: To use a musculoskeletal model of the lower limb to evaluate the effect of a strength training intervention on the muscle and joint contact forces experienced by untrained women during landing. Methods: Sixteen untrained women between 18 and 28 years participated in this cohort study, split equally between intervention and control groups. The intervention group trained for 8 weeks targeting improvements in posterior leg strength. The mechanics of bilateral and unilateral drop landings from a 30 cm platform were recorded preintervention and postintervention, as was the isometric strength of the lower limb during a hip extension test. The internal muscle and joint contact forces were calculated using FreeBody, a musculoskeletal model. Results: The strength of the intervention group increased by an average of 35% (P<0.05; pre: 133±36 n, post: 180±39 n), whereas the control group showed no change (pre: 152±36 n, post: 157±46 n). There were only small changes from pre-test to post-test in the kinematics and ground reaction forces during landing that were not statistically significant. Both groups exhibited a post-test increase in gluteal muscle force during landing and a lateral to medial shift in tibiofemoral joint loading in both landings. However, the magnitude of the increase in gluteal force and lateral to medial shift was significantly greater in the intervention group. Conclusion: Strength training can promote a lateral to medial shift in tibiofemoral force (mediated by an increase in gluteal force) that is consistent with a reduction in valgus loading. This in turn could help prevent injuries that are due to abnormal knee loading such as anterior cruciate ligament ruptures, patellar dislocation and patellofemoral pain.
Karunaratne A, Li S, Bull AMJ, 2018, Nano-scale mechanisms explain the stiffening and strengthening of ligament tissue with increasing strain rate., Sci Rep, Vol: 8
Ligament failure is a major societal burden causing disability and pain. Failure is caused by trauma at high loading rates. At the macroscopic level increasing strain rates cause an increase in failure stress and modulus, but the mechanism for this strain rate dependency is not known. Here we investigate the nano scale mechanical property changes of human ligament using mechanical testing combined with synchrotron X-ray diffraction. With increasing strain rate, we observe a significant increase in fibril modulus and a reduction of fibril to tissue strain ratio, revealing that tissue-level stiffening is mainly due to the stiffening of collagen fibrils. Further, we show that the reduction in fibril deformation at higher strain rates is due to reduced molecular strain and fibrillar gaps, and is associated with rapid disruption of matrix-fibril bonding. This reduction in number of interfibrillar cross-links explains the changes in fibril strain; this is verified through computational modelling.
Klemt C, Prinold JA, Morgans S, et al., 2018, Analysis of shoulder compressive and shear forces during functional activities of daily life, CLINICAL BIOMECHANICS, Vol: 54, Pages: 34-41, ISSN: 0268-0033
Injuries sustained due to attacks from explosive weapons are multiple in number, complex in nature, and not well characterised. Blast may cause damage to the human body by the direct effect of overpressure, penetration by highly energised fragments, and blunt trauma by violent displacements of the body. The ability to reproduce the injuries of such insults in a well-controlled fashion is essential in order to understand fully the unique mechanism by which they occur, and design better treatment and protection strategies to alleviate the resulting poor long-term outcomes. This paper reports a range of experimental platforms that have been developed for different blast injury models, their working mechanism, and main applications. These platforms include the shock tube, split-Hopkinson bars, the gas gun, drop towers and bespoke underbody blast simulators.
Papi E, Bull AMJ, McGregor AH, 2018, Is there evidence to use kinematic/kinetic measures clinically in low back pain patients? A systematic review., Clin Biomech (Bristol, Avon), Vol: 55, Pages: 53-64
BACKGROUND: Currently, there is a widespread reliance on self-reported questionnaires to assess low back pain patients. However, it has been suggested that objective measures of low back pain patients' functional status should be used to aid clinical assessment. The aim of this study is to systematically review which kinematic /kinetic parameters have been used to assess low back pain patients against healthy controls and to propose clinical kinematic/kinetic measures. METHODS: PubMed, Embase and Scopus databases were searched for relevant studies. Reference lists of selected studies and hand searches were performed. Studies had to compare people with and without non-specific low back pain while performing functional tasks and report body segment/joint kinematic and/or kinetic data. Two reviewers independently identified relevant papers. FINDINGS: Sixty-two studies were included. Common biases identified were lack of assessor blinding and sample size calculation, use of samples of convenience, and poor experimental protocol standardization. Studies had small sample sizes. Range of motion maneuvers were the main task performed (33/62). Kinematic/kinetic data of different individual or combination of body segments/joints were reported among the studies, commonest was to assess the hip joint and lumbar segment motion (13/62). Only one study described full body movement. The most commonly reported outcome was range of motion. Statistically significant differences between controls and low back pain groups were reported for different outcomes among the studies. Moreover, when the same outcome was reported disagreements were noted. INTERPRETATION: The literature to date offers limited and inconsistent evidence of kinematic/kinetic measures in low back pain patients that could be used clinically.
Rosenberg N, Bull AMJ, 2018, Simulating localised cellular inflammation and substrate properties in a strain energy density based bone remodelling algorithm for use in modelling trauma., Comput Methods Biomech Biomed Engin, Vol: 21, Pages: 208-218
Bone responds to mechanical stimulus and a range of pre-existing finite element models have been suggested to reproduce the internal physiological structure of bone. Inflammation effects are not included in these models, yet inflammation is a key component of bone repair in trauma. Therefore, a model is proposed and tested here that extends these methods to include parameters that could be considered to represent the behaviour of bone remodelling when influenced by inflammation. The proposed model regulates remodelling based on findings from recent studies into the nature of heterotopic ossification, the formation of heterotopic bone, which have revealed information about the nature of bone after high levels of trauma. These parameters include consideration of the distance from the zone of trauma, the density of mesenchymal stem cells, and substrate stiffness as a trigger for cells becoming osteogenic. The method is tested on a two-dimensional plate model and shows that the new extended algorithm can produce a range of structures depending on inputs that could be used in the future to replicate physiological scenarios.
Cheong VS, Karunaratne A, Amis AA, et al., 2017, Strain rate dependency of fractures of immature bone, JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS, Vol: 66, Pages: 68-76, ISSN: 1751-6161
Eftaxiopoulou T, Persad L, Bull AMJ, 2017, Assessment of performance parameters of a series of five 'historical' cricket bat designs, Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology, Vol: 231, Pages: 57-62, ISSN: 1754-3371
© 2017 Institution of Mechanical Engineers. The performance of five different bat designs, from different eras spanning from 1905 to 2013, was assessed to address the question whether the changes in bat design over the years have resulted in a performance advantage to the batsman. Moment of inertia and 'freely suspended' vibration analysis tests were conducted, as these physical properties have been directly associated with rebound characteristics of the bats. Results showed that changes in the blade's profile such as distribution of the blade's weight along the edges and closer to the toe have resulted in a clear performance advantage of the newest bats in comparison with older designs. These results add to the weight of evidence in cricket that the game has changed to the benefit of the batsman and additional changes to bat design are conceivable as modern engineering tools are applied to further optimise performance.
Grigoriadis G, Newell N, Carpanen D, et al., 2017, Material properties of the heel fat pad across strain rates, JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS, Vol: 65, Pages: 398-407, ISSN: 1751-6161
Junaid S, Sanghavi S, Anglin C, et al., 2017, Treatment of the Fixation Surface Improves Glenoid Prosthesis Longevity in vitro, JOURNAL OF BIOMECHANICS, Vol: 61, Pages: 81-87, ISSN: 0021-9290
Klemt C, Nolte D, Grigoriadis G, et al., 2017, The contribution of the glenoid labrum to glenohumeral stability under physiological joint loading using finite element analysis, COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING, Vol: 20, Pages: 1613-1622, ISSN: 1025-5842
Panagiotakis E, Mok K-M, Fong DT-P, et al., 2017, Biomechanical analysis of ankle ligamentous sprain injury cases from televised basketball games: Understanding when, how and why ligament failure occurs., J Sci Med Sport, Vol: 20, Pages: 1057-1061
OBJECTIVES: Ankle sprains due to landing on an opponent's foot are common in basketball. There is no analysis to date that provides a quantification of this injury mechanism. The aim of this study was to quantify the kinematics of this specific injury mechanism and relate this to lateral ankle ligament biomechanics. DESIGN: Case series. METHODS: The model-based image-matching technique was used to quantify calcaneo-fibular-talar kinematics during four ankle inversion sprain injury incidents in televised NBA basketball games. The four incidents follow the same injury pattern in which the players of interest step onto an opponent's foot with significant inversion and a diagnosed ankle injury. A geometric analysis was performed to calculate the in vivo ligament strains and strain rates for the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL). RESULTS: Despite the controlled selection of cases, the results show that there are two distinct injury mechanisms: sudden inversion and internal rotation with low levels of plantarflexion; and a similar mechanism without internal rotation. The first of these mechanisms results in high ATFL and CFL strains, whereas the second of these strains the CFL in isolation. CONCLUSIONS: The injury mechanism combined with measures of the ligament injury in terms of percentage of strain to failure correlate directly with the severity of the injury quantified by return-to-sport. The opportunity to control excessive internal rotation through proprioceptive training and/or prophylactic footwear or bracing could be utilised to reduce the severity of common ankle injuries in basketball.
Pandis P, Bull AM, 2017, A low-cost three-dimensional laser surface scanning approach for defining body segment parameters., Proc Inst Mech Eng H, Vol: 231, Pages: 1064-1068
Body segment parameters are used in many different applications in ergonomics as well as in dynamic modelling of the musculoskeletal system. Body segment parameters can be defined using different methods, including techniques that involve time-consuming manual measurements of the human body, used in conjunction with models or equations. In this study, a scanning technique for measuring subject-specific body segment parameters in an easy, fast, accurate and low-cost way was developed and validated. The scanner can obtain the body segment parameters in a single scanning operation, which takes between 8 and 10 s. The results obtained with the system show a standard deviation of 2.5% in volumetric measurements of the upper limb of a mannequin and 3.1% difference between scanning volume and actual volume. Finally, the maximum mean error for the moment of inertia by scanning a standard-sized homogeneous object was 2.2%. This study shows that a low-cost system can provide quick and accurate subject-specific body segment parameter estimates.
Pearce AP, Bull AMJ, Clasper JC, 2017, Mediastinal injury is the strongest predictor of mortality in mounted blast amongst UK deployed forces., Injury, Vol: 48, Pages: 1900-1905
BACKGROUND: Blast injury has been the most common cause of morbidity and mortality encountered by UK forces during recent conflicts. Injuries sustained by blast are categorised by the injuring component of the explosion and depend upon physical surroundings. Previous work has established that head injuries and intra cavity haemorrhage are the major causes of death following exposure to under body (mounted) blast but has yet to explore the precise nature of these torso injuries nor the effect of particular injuries upon survival. This study examines the patterns of torso injury within the mounted blast environment in order to understand the effect of these injuries upon survivability. METHODS: This retrospective study examined the UK Joint Theatre Trauma Registry to determine precise injury patterns of mounted blast casualties within a 13year period of UK military deployments. Survival rates of individual injuries were compared and a multivariable logistic regression model was developed in order to assess the effect that each injury had upon likelihood of death. RESULTS: 426 mounted casualties were reviewed of whom 129 did not survive. Median NISS and ISS for non-survivors was found to be 75. Torso injuries were significantly more common amongst non-survivors than survivors and high case fatality rates were associated with all haemorrhagic torso injuries. Multivariable analysis shows that mediastinal injuries have the largest odds ratio for mortality (20.4) followed by lung laceration and head injury. CONCLUSIONS: Non-compressible torso haemorrhage is associated with mortality amongst mounted blast. Of this group, mediastinal injury is the strongest predictor of death and could be considered as a surrogate marker of lethality. Future work to link blast loading characteristics with specific injury patterns will inform the design of mitigating strategies in order to improve survivability of underbody blast.
Pearce AP, Bull AMJ, Clasper JC, 2017, Re: Mediastinal injury is the strongest predictor of mortality in mounted blast amongst UK deployed forces: Methodological issues., Injury, Vol: 48
Amabile C, Bull AMJ, Kedgley AE, 2016, The centre of rotation of the shoulder complex and the effect of normalisation, JOURNAL OF BIOMECHANICS, Vol: 49, Pages: 1938-1943, ISSN: 0021-9290
Barnett-Vanes A, Sharrock A, Eftaxiopoulou T, et al., 2016, CD43Lo classical monocytes participate in the cellular immune response to isolated primary blast lung injury, JOURNAL OF TRAUMA AND ACUTE CARE SURGERY, Vol: 81, Pages: 500-511, ISSN: 2163-0755
Buckeridge EM, Bull AMJ, McGregor AH, 2016, Incremental training intensities increases loads on the lower back of elite female rowers, JOURNAL OF SPORTS SCIENCES, Vol: 34, Pages: 369-378, ISSN: 0264-0414
Buckeridge EM, Weinert-Aplin RA, Bull AMJ, et al., 2016, Influence of foot-stretcher height on rowing technique and performance, SPORTS BIOMECHANICS, Vol: 15, Pages: 513-526, ISSN: 1476-3141
Campos-Pires R, Dickinson R, 2016, Modelling Blast Brain Injury, Blast Injury Science and Engineering A Guide for Clinicians and Researchers, Editors: Clasper, Bull, Mahoney, Publisher: Springer, Pages: 173-182, ISBN: 9783319218670
The consequences of blast traumatic brain injury (blast-TBI) in humans are largely determined by the characteristics of the trauma insult and, within certain limits, the individual responses to the lesions inflicted (1). In blast-TBI the mechanisms of brain vulnerability to the detonation of an explosive device are not entirely understood. They most likely result from a combination of the different physical aspects of the blast phenomenon, specifically extreme pressure oscillations (blast-overpressure wave), projectile penetrating fragments and acceleration-deceleration forces, creating a spectrum of brain injury that ranges from mild to severe blast-TBI (2). The pathophysiology of penetrating and inertially-driven blast-TBI has been extensively investigated for many years. However, the brain damage caused by blast-overpressure is much less understood and is unique to this type of TBI (3). Indeed, there continues to be debate about how the pressure wave is transmitted and reflected through the brain and how it causes cellular damage (4). No single model can mimic the clinical and mechanical complexity resulting from a real life blast-TBI (3). The different models, non-biological (in silico or surrogate physical) and biological (ex vivo, in vitro or in vivo), tend to complement each other.
Eftaxiopoulou T, Barnett-Vanes A, Arora H, et al., 2016, Prolonged but not short-duration blast waves elicit acute inflammation in a rodent model of primary blast limb trauma, INJURY-INTERNATIONAL JOURNAL OF THE CARE OF THE INJURED, Vol: 47, Pages: 625-632, ISSN: 0020-1383
Eftaxiopoulou T, Chaillot V, Bull AMJ, 2016, Interaction between equipment and athlete performance in racket sports: A cricketing story, Sports Innovation, Technology and Research, Pages: 43-62, ISBN: 9781786340429
Fratini A, Bonci T, Bull AMJ, 2016, Whole Body Vibration Treatments in Postmenopausal Women Can Improve Bone Mineral Density: Results of a Stimulus Focussed Meta-Analysis, PLOS ONE, Vol: 11, ISSN: 1932-6203
Greenberg N, Bull A, Wessely S, 2016, Chilcot: physical and mental legacy of Iraq war on UK service personnel., BMJ, Vol: 354
Grigoriadis G, Carpanen D, Bull AMJ, et al., 2016, A finite element model of the foot and ankle for prediction of injury in under-body blast, Pages: 457-458
McGregor AH, Buckeridge E, Murphy AJ, et al., 2016, Communicating and using biomechanical measures through visual cues to optimise safe and effective rowing, PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART P-JOURNAL OF SPORTS ENGINEERING AND TECHNOLOGY, Vol: 230, Pages: 246-252, ISSN: 1754-3371
Newell N, Salzar R, Bull AMJ, et al., 2016, A validated numerical model of a lower limb surrogate to investigate injuries caused by under-vehicle explosions, JOURNAL OF BIOMECHANICS, Vol: 49, Pages: 710-717, ISSN: 0021-9290
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