Biomechanical risk factors of lower back pain in cricket fast bowlers using inertial measurement units: a prospective and retrospective investigation.

Objectives: To investigate spinal kinematics, tibial and sacral impacts during fast bowling, among bowlers with a history of low back pain (LBP) (retrospective) and bowlers who developed LBP in the follow-up season (prospective). Methods: 35 elite male fast bowlers; senior (n=14; age=24.1±4.3 years; height=1.89±0.05 m; weight=89.2±4.6 kg) and junior (n=21; age=16.9±0.7; height=1.81±0.05; weight=73.0±9.2 kg) were recruited from professional county cricket clubs. LBP history was gathered by questionnaire and development of LBP was monitored for the follow-up season. Spinal kinematics, tibial and sacral impacts were captured using inertial measurement units placed over S1, L1, T1 and anteromedial tibia. Bonferroni corrected pairwise comparisons and effect sizes were calculated to investigate differences in retrospective and prospective LBP groups. Results: Approximately 38% of juniors (n=8) and 57% of seniors (n=8) reported a history of LBP. No differences were evident in spinal kinematics or impacts between those with LBP history and those without for seniors and juniors. Large effect sizes suggest greater rotation during wind-up (d=1.3) and faster time-to-peak tibial impacts (d=1.5) in those with no history of LBP. One junior (5%) and four (29%) seniors developed LBP. No differences were evident in spinal kinematics or impacts between those who developed LBP and those who did not for seniors. In seniors, those who developed LBP had lower tibial impacts (d=1.3) and greater lumbar extension (d=1.9) during delivery. Conclusion: Retrospective analysis displayed non-significant differences in kinematics and impacts. It is unclear if these are adaptive or impairments. Prospective analysis demonstrated large effect sizes for lumbar extension during bowling suggesting a target for future coaching interventions

THE USE OF INERTIAL MEASUREMENT UNITS TO IDENTIFY BIOMECHANICAL FACTORS OF PERFORMANCE IN CRICKET FAST BOWLERS

The role of a cricket bowler is to deliver the ball in such a way as to minimise batsmen scoring runs or get them out. Fast bowlers utilise the pace of delivery as a key tool to achieve this. The purpose of this study was to use inertial measurement units (IMUs) to investigate the relationship between IMU derived spinal kinematics, lower limb accelerations and ball release speed in cricket fast bowlers. Sacral vertical loading rate at back-foot impact and thoracic lateral flexion at front-foot impact displayed significant positive relationships with ball release speed (r=.521 and .629 respectively). Consequently, this study highlights IMUs are able to effectively identify trends in fast bowling performance and hence, larger accelerations at back-foot impact with increased lateral flexion at front-foot impact were effective strategies to increase ball release speed for the bowlers measured in this study

An investigation into the spinal kinematics and lower limb impacts during cricket fast bowling and their association with lower back pain.

Cricket fast bowlers have been highlighted as having increased risk of injury when compared to the rest of the team. Lower back injury and more specifically, pain results in more time away from cricket than any other injury in the fast bowling population, with juniors displaying even greater risk compared with senior fast bowlers. Whilst lower back injury (confirmed musculoskeletal diagnoses, usually radiographically) in fast bowlers has been repeatedly investigated. Lower back pain (LBP), defined as pain resulting in time away from matchplay or training with or without a formal diagnosis, (highlighted to display a different relationship to injury) has received little attention in fast bowling literature. High bowling workloads (usually recorded in overs or days bowled) and the immature spine of junior fast bowlers have been highlighted as significantly increasing risk of injury. However, research regarding specific kinematic and kinetic risk factors requires further attention. Therefore, this study aimed to address current methodological limitations to investigate the association between spinal kinematics and lower limb impacts during fast bowling and risk of LBP in junior and senior fast bowlers. This study compares bowling kinematics and lower limb impacts in junior and senior fast bowlers and retrospective and prospective LBP risk, to provide additional insight into the clinical biomechanics of fast bowling. This study has shown inertial sensors and accelerometers are a valid (r>0.8 for 79% of variables, RMSEP = 0.3-1.5°) and reliable (ICC’s >0.8 and SEM<3.4g and 9°) method of analysing fast bowling lower limb impacts and spinal kinematics and may therefore be an acceptable alternative to current methodologies. Analysis of tibial impacts on different playing surfaces displayed larger impacts on outdoor artificial surfaces (26.6g) compared with grass (24.7g) and indoor rubber (22.0g) and wood (17.8g). Highlighting, large workloads on outdoor artificial surfaces may increase injury risk, with a wooden indoor surface more favourable. Retrospective and prospective LBP and injury data highlighted that senior fast bowlers with known spinal pathologies displayed four times greater risk of future LBP. However, this was not necessarily the case in junior bowlers. Results highlighted that peak accelerations at back-foot impact were higher in bowlers with no history of LBP, as well as bowlers that did not develop LBP in the follow-up season with differences between 8-10g seen in peak tibial acceleration. This may be a potential mechanism of reducing load at front-foot impact (which showed few notable differences between groups). Junior bowlers with a history of LBP displayed less contralateral thoracic rotation at back-foot impact and consequently a lower overall range. However, this trend was not displayed in senior bowlers. Senior bowlers, with either a history of LBP or that went on to develop LBP bowled with almost double lumbar extension (9° to 16°) resulting in a 12° increase in thoracolumbar extension at back-foot impact. Therefore, this study suggests that higher magnitudes of fast bowling impacts may not be synonymous with increased risk of LBP, however spinal kinematics at back-foot impact may provide some insight into bowlers’ risk of developing LBP. The effect of these recommendations on fast bowling performance was analysed through a correlation of impact and spinal kinematics with ball release speed. This highlighted that the recommendations to reduced risk of LBP are not likely to affect ball release speed, as only sacral loading rate at back foot impact and thoracic lateral flexion at FFI showed significant correlations with ball release speed (r=.521 and .629 respectively). Overall this study has demonstrated the application of novel technology applied to the live cricket fast bowling situation, overcoming limitations of previous methods. The method was valid, reliable and sensitive enough to determine significant differences in the spinal kinematics which were associated with LBP history or with developing LBP in the follow-up season and these were specific to junior and senior bowlers. These new insights will help to inform surveillance and coaching practices in the quest to reduce the injurious nature of fast bowling

Conflict-free routing of multi-stop warehouse trucks

The recent interest in greater vehicular autonomy for factory and warehouse automation has stimulated research in conflict-free routing: a challenging network routing problem in which vehicles may not pass each other. Motivated by a real-world case study, we consider one such application: truck movements in a tightly constrained warehouse. We propose an extension of an existing conflict-free routing algorithm to consider multiple stopping points per route. A high level metaheuristic is applied to determine the route construction and assignment of vehicles to routes

Are shoulder counter rotation and hip shoulder separation angle representative metrics of three-dimensional spinal kinematics in cricket fast bowling?

This study aimed to investigate the relationship between shoulder counter-rotation (SCR), hip shoulder separation (HSS) and three-dimensional spinal kinematics during fast bowling in cricket. Thirty five elite male fast bowlers were analysed using three-dimensional inertial sensors on the spine. Lumbar, thoracic and thoracolumbar kinematics were determined during the delivery stride. Spearman's pairwise correlations displayed significant associations between SCR, thoracic and thoracolumbar lateral flexion between the back foot impact and max contralateral rotation phase of the delivery stride (rs = -.462 and -.460). HSS and thoracolumbar lateral flexion displayed a significant correlation between back foot impact and max contralateral rotation (rs = -.552). No other significant correlations were observed. These results suggest SCR and HSS are modestly related to lateral flexion, leaving a large component of SCR and HSS unrelated to specific three-dimensional spinal kinematics. It is possible that this represents changes in whole spinal orientation and not resultant spinal motion. Despite this, SCR remains the only metric currently related to injury and therefore is important; however it is only a very modest proxy for more traditional descriptions of spinal motion

Ground reaction force, spinal kinematics and their relationship to lower back pain and injury in cricket fast bowling: A review

BACKGROUND: Fast bowlers display a high risk of lower back injury and pain. Studies report factors that may increase this risk, however exact mechanisms remain unclear. OBJECTIVE: To provide a contemporary analysis of literature, up to April 2016, regarding fast bowling, spinal kinematics, ground reaction force (GRF), lower back pain (LBP) and pathology. METHOD: Key terms including biomechanics, bowling, spine and injury were searched within MEDLINE, Google Scholar, SPORTDiscuss, Science Citation Index, OAIster, CINAHL, Academic Search Complete, Science Direct and Scopus. Following application of inclusion criteria, 56 studies (reduced from 140) were appraised for quality and pooled for further analysis. RESULTS: Twelve times greater risk of lumbar injury was reported in bowlers displaying excessive shoulder counter-rotation (SCR), however SCR is a surrogate measure which may not describe actual spinal movement. Little is known about LBP specifically. Weighted averages of 5.8 ± 1.3 times body weight (BW) vertically and 3.2 ± 1.1 BW horizontally were calculated for peak GRF during fast bowling. No quantitative synthesis of kinematic data was possible due to heterogeneity of reported results. CONCLUSIONS: Fast bowling is highly injurious especially with excessive SCR. Studies adopted similar methodologies, constrained to laboratory settings. Future studies should focus on methods to determine biomechanics during live play

Haiku - a Scala combinator toolkit for semi-automated composition of metaheuristics

There is an emerging trend towards the automated design of metaheuristics at the software component level. In principle, metaheuristics have a relatively clean decomposition, where well-known frameworks such as ILS and EA are parametrised by variant components for acceptance, perturbation etc. Automated generation of these frameworks is not so simple in practice, since the coupling between components may be implementation specific. Compositionality is the ability to freely express a space of designs ‘bottom up’ in terms of elementary components: previous work in this area has used combinators, a modular and functional approach to componentisation arising from foundational Computer Science. In this article, we describeHaiku, a combinator tool-kit written in the Scala language, which builds upon previous work to further automate the process by automatically composing the external dependencies of components. We provide examples of use and give a case study in which a programatically-generated heuristic is applied to the Travelling Salesman Problem within an Evolutionary Strategies framework

Metaheuristics “In the Large”

Many people have generously given their time to the various activities of the MitL initiative. Particular gratitude is due to Adam Barwell, John A. Clark, Patrick De Causmaecker, Emma Hart, Zoltan A. Kocsis, Ben Kovitz, Krzysztof Krawiec, John McCall, Nelishia Pillay, Kevin Sim, Jim Smith, Thomas Stutzle, Eric Taillard and Stefan Wagner. J. Swan acknowledges the support of UK EPSRC grant EP/J017515/1 and the EU H2020 SAFIRE Factories project. P. GarciaSanchez and J. J. Merelo acknowledges the support of TIN201785727-C4-2-P by the Spanish Ministry of Economy and Competitiveness. M. Wagner acknowledges the support of the Australian Research Council grants DE160100850 and DP200102364.Following decades of sustained improvement, metaheuristics are one of the great success stories of opti- mization research. However, in order for research in metaheuristics to avoid fragmentation and a lack of reproducibility, there is a pressing need for stronger scientific and computational infrastructure to sup- port the development, analysis and comparison of new approaches. To this end, we present the vision and progress of the Metaheuristics “In the Large”project. The conceptual underpinnings of the project are: truly extensible algorithm templates that support reuse without modification, white box problem descriptions that provide generic support for the injection of domain specific knowledge, and remotely accessible frameworks, components and problems that will enhance reproducibility and accelerate the field’s progress. We argue that, via such principled choice of infrastructure support, the field can pur- sue a higher level of scientific enquiry. We describe our vision and report on progress, showing how the adoption of common protocols for all metaheuristics can help liberate the potential of the field, easing the exploration of the design space of metaheuristics.UK Research & Innovation (UKRI)Engineering & Physical Sciences Research Council (EPSRC) EP/J017515/1EU H2020 SAFIRE Factories projectSpanish Ministry of Economy and Competitiveness TIN201785727-C4-2-PAustralian Research Council DE160100850 DP20010236

Hybrid meta-heuristic frameworks : a functional approach

Problems requiring combinatorial optimisation are routinely encountered in research and applied computing. Though polynomial-time algorithms are known for certain problems, formany practical problems, frommundane tasks in scheduling through to exotic tasks such as sequence alignment in bioinformatics, the only effective approach is to use heuristic methods. In contrast to complete strategies that locate globally optimal solutions through (in the worst case) the enumeration of all solutions to a problem, heuristics are based upon rules of thumb about specific problems, which guide the search down promising avenues. Work in the field of Operations Research has gone further, developing generic metaheuristics, abstract templates which may be adapted to tackle many different problems. Metaheuristic researchers have created a variety of algorithms, each with their own strengths and weaknesses, and development of metaheuristics now often tries to combine concepts from a number of existing strategies to balance the advantages of the originals, known as hybridisation. This interest in hybridisation has led to the creation of a number of frameworks in imperative languages to assist programmers in the rapid creation and experimentation upon the algorithms. However these existing frameworks have struggled to enable hybridisation of the two major classes of metaheuristic, point based and population based, while being large and complicated to use. This Thesis investigates a functional approach to hybridisation. Despite superficial analogies between hybridisation and function composition, there are substantial challenges: unlike global search methods that can be explained elegantly in terms of graph traversal, prior work on local search has struggled to articulate a common model, let alone one that can accommodate more esoteric optimisation techniques such as ant colony optimisation. At the same time, these implementations cannot ignore the fact that the development of these techniques is driven by large-scale problems, and computational efficiency cannot be ignored. Given this background, this Thesis makes three substantial contributions. It decomposes metaheuristic searchmethods into a set of finer-grained concepts and tools that can be reassembled to describe both standard search strategies and more specialised approaches. It resolves problems found in implementing these abstractions in the widely used language Haskell, developing a novel approach based on dataflow networks. The value of functional abstraction in the practice of metaheuristic development and tuning is demonstrated through case studies, including a substantial problem in bioinformatics

The Multiple Uses of Monte-Carlo Tree Search

Modern production processes are continuing to move towards more flexible and dynamic conditions, most clearly exemplified by mass customization, but this flexibility can also be seen in technologies like; Human-Robot Collaboration, Automated Guided Vehicle fleets for just in time delivery of parts within factories and reconfigurable manufacturing. Currently, these technologies are developing independently of one another and the supporting industrial software tools such as line balancing optimisation tools, Machine Execution Systems and fleet management tools are similarly developing independently. An alternative to developing individual technologies for each problem is the use of a shared algorithmic framework that can support all of these problem types and future research into general smart factory technology. Monte Carlo Tree Search is a relatively recent Artificial Intelligence algorithm, sometimes described as a general-purpose heuristic, that has been found to be very effective in several theoretical and game-related problems. This paper will review the current growth in research into possible industrial applications of this algorithm and how a framework utilising this algorithm can help to realise the aims of the smart factory vision.CC BY-NC 4.0The author wishes to thank Marie Schnell, Bernard Schmidt and Carlos Alberto Barrera Diaz for their advice and support in preparing this paper.</p