COST OF TRANSPORT, LOWER LIMBS ASIMMETRY AND THE DYNAMICS OF RUNNING.

The main topic of my PhD project regards the effects of the human symmetry on energetic and locomotion. The concept of symmetry, applied in many and different fields, from arts to physical sciences, has been always related to beauty, balance and equilibrium. Most individuals, animals and humans as well, are characterized by an almost complete morphological bilateral symmetry, and the deviation from it caused by environmental stresses, developmental instability and genetic problems, is called Fluctuating Asymmetry (FA). In numerous studies regarding FA, it has been demonstrated that this index is related to several different features, like sexual selection, body mass, running performance in humans and in racehorses. Similarly, symmetry plays a key role in the maintenance and design of our vehicles. They are periodically inspected, to guarantee a wheel balance/alignment and homogeneous tyre wearing. In this way the fuel consumption can be reduced. The main aim of this project has its origin from the comparison between mechanical vehicles and the human body. In human locomotion the skeletal muscles (the motor), and the limb lever system (the machine), interact together, in order to produce the movements of the whole body system. We assume that an anatomical or structural symmetry of the human body could have effects on the dynamic asymmetry during locomotion and also could be related to some metabolic energy saving. Several authors studied symmetry in locomotion with different methodological approaches in human, but also in animals. Different symmetry indices were found in order to classify subjects in different categories, or for pattern identification and pathologies diagnosis, but the relationships between symmetry and the Cost of Transport were poorly investigated. Gait symmetry has been defined as a perfect agreement between the actions of the lower limbs and general this assumption was adopted to simplify data collection and analysis of the lower limbs. Gait asymmetry instead, does not appear to be the consequence of abnormality, but rather reflects natural functional differences between the lower extremities. In the present study, we tried to validate our hypothesis, investigating anatomical and, dynamical symmetries, and the cost of transport in 19 different aged and trained male runners, in order to find out significant relationships between these parameters. Subjects were divided in three categories: Occasional Runners (OR), Skilled Runners (SR) and Top Runners (TR), depending of their training/performance level. Differently from others studies, we compare two different kinds of symmetries: the dynamic symmetry during running at different velocities (i.e. spatial differences, in Body Center of Mass (BCOM) trajectory, between two step), and the anatomical symmetry of the human lower limbs. A Magnetic Resonance (MR) protocol was applied for each subject, to evaluate the anatomical symmetry of three different anatomical districts Pelvis district (PD), Upper-Leg district (UD) and Lower-Leg district (LD). All the recorded images were analyzed with a custom, ad hoc program that can identify the MR images and calculate a cross correlation index, between right lower limb and left lower limb. This anatomical symmetry index can assume values from -1 to 1 and it is bigger the more the subject\u2019s limbs are symmetrical. Level running at incremental velocities on a treadmill was performed in order to record kinematic functional symmetries. The human body was modelled as a series of linked, rigid segments with twenty reflective markers and their positions were captured by an optoelectronic system in order to evaluate trajectory of the BCOM. The coordinate describing this position were successively used to evaluate the main aspects of the gaits and the individual characteristics of movements, a sort of \u201clocomotion signature\u201d capable to reflect any significant change in the motion pattern. The time course of each of the 3 BCOM coordinates was fit by a Fourier Series and three single anatomical indices (one for each direction) were calculated. To evaluate running economy, heart rate (HR) and oxygen consumption (VO2) were measured continuously during level running/kinematic registration. The hypothesis we assumed, arising from to the world of the motor vehicles, found some answers with the results obtained in this work. The human body and the mechanical vehicle seem to have some similarity regarding the structure stability. In the human body, a high level of dynamical symmetry, during running locomotion is accompanied by structural/anatomical symmetry, but, differently from the motor vehicles, the energetic consumption doesn\u2019t change with the level of anatomical and dynamic symmetry. Furthermore, training seems to be an important element in the stability and in the dynamical symmetry of running, even if no relationship was found between training level and Cost of transport. Also we found significant negative correlations between anatomical/structural symmetry and subject age. According to the literature asymmetry increase with the age of the subjects. We can conclude that our body can be biased by asymmetrical anatomical structures of the lower limb in the dynamical symmetry of the BCOM displacement, but without changing the energetic cost of running. Maybe some physiological adaptations of the human machine can compensate for small imperfections in the mechanics of our legged system, with no influence on the metabolic cost of transport, while larger anatomical imperfection, like length legs discrepancy or a body mass not uniformly distributed, or also prosthesis and support for pathological situations, could have a significant effect on the energetic cost of transport. This work brings new developments in the study of symmetry in locomotion, both for the introduced methods and for the presented result. Anyway further developments could be carried out in order to understand the already obtained results. The number of participants should increase and a longitudinal work could be carried out in order to find out differences between groups. Furthermore kinematic and energetic recording should be performed for a longer period. In this way the subjects could arise higher running velocity, and also we could observe new physiological parameters that we didn\u2019t notice in only some minutes of registration

EVALUATION OF TACKLING BIOMECHANICS IN RUGBY: VIDEO INCIDENT ANALYSIS AND EXPERIMENTAL SET UP

This study consisted of a video incident analysis of rugby tackles leading to spinal injuries, where players’ behaviours and observed loading mechanisms were coded for each incident. The key features of these events were summarised, revealing the role of highspeed impacts, illegal tackles, and poor tackle technique in injury-causing tackles. In addition, lateral bending moments and lateral flexion movements were more prevalent than suggested by previous research. This investigation informed an experimental protocol for the analysis of simulated rugby tackles, with the final goal to obtain measures of cervical spine biomechanics during tackles. Data captured from this protocol could also be input into a full-body musculoskeletal model to provide descriptions of internal cervical spine loading in different tackle event scenarios

A personalised prosthetic liner with embedded sensor technology:a case study

BACKGROUND: Numerous sensing techniques have been investigated in an effort to monitor the main parameters influencing the residual limb/prosthesis interface, fundamental to the optimum design of prosthetic socket solutions. Sensing integration within sockets is notoriously complex and can cause user discomfort. A personalised prosthetic liner with embedded sensors could offer a solution. However, to allow for a functional and comfortable instrumented liner, highly customised designs are needed. The aim of this paper is to presents a novel approach to manufacture fully personalised liners using scanned three-dimensional image data of the patient's residual limb, combined with designs that allow for sensor integration. To demonstrate the feasibility of the proposed approach, a personalised liner with embedded temperature and humidity sensors was realised and tested on a transtibial amputee, presented here as a case study. METHODS: The residual limb of a below knee amputee was first scanned and a three-dimensional digital image created. The output was used to produce a personalised prosthesis. The liner was manufactured using a cryogenic Computer Numeric Control (CNC) machining approach. This method enables fast, direct and precise manufacture of soft elastomer products. Twelve Hygrochron Data Loggers, able to measure both temperature and humidity, were embedded in specific liner locations, ensuring direct sensor-skin contact. The sensor locations were machined directly into the liner, during the manufacturing process. The sensors outputs were assessed on the below amputee who took part in the study, during resting (50 min) and walking activities (30 min). To better describe the relative thermal properties of new liner, the same tests were repeated with the amputee wearing his existing liner. Quantitative comparisons of the thermal properties of the new liner solution with that currently used in clinical practice are, therefore, reported. RESULTS: The liner machining process took approximately 4 h. Fifteen minutes after donning the prosthesis, the skin temperature reached a plateau. Physical activity rapidly increased residuum skin temperatures, while cessation of activity caused a moderate decrease. Humidity increased throughout the observation period. In addition, the new liner showed better thermal properties with respect to the current liner solution (4% reduction in skin temperature). CONCLUSIONS: This work describes a personalised liner solution, with embedded temperature and humidity sensors, developed through an innovative approach. This new method allows for a range of sensors to be smoothly embedded into a liner, which is capable of measuring changes in intra-socket microclimate conditions, resulting in the design of advanced socket solutions personalised specifically for individual requirements. In future, this method will not only provide a personalised liner but will also enable dynamic assessment of how a residual limb behaves within the socket during daily activities.</p

BIOMECHANICAL LOADS IN RUGBY UNION TACKLING ARE AFFECTED BY TACKLE DIRECTION AND IMPACT SHOULDER

Approximately 25% of Rugby Union injuries occur to players executing a tackle and they mostly involve upper-body regions. We designed novel tackle simulator to investigate upper-body loading under different tackling conditions: direction of approach and side of body used. Dominant shoulder tackles in the frontal direction generated the highest impact forces, 5.3 ± 1.0 kN (15% higher than non-dominant) and the lowest range of neck flexion (20% lower than non-dominant) at impact. Impact load decreased going from frontal to diagonal (-3%) and lateral tackling (-10%). The lowest peak head acceleration and angular velocity resulted from diagonal tackles with the dominant shoulder. For injury prevention, the tackler should approach from an offset angle from frontal and coaching should aim to reduce the deficiencies in tackling technique on the non-dominant side

Antimicrobial resistance profiles and characterization of Escherichia coli strains from cases of neonatal diarrhea in Spanish pig farms

Escherichia coli is considered one of the most common agents associated with neonatal diarrhea in piglets. The aim of this work was to characterize the pathogenic and antimicrobial resistance (AMR) profiles of 122 E. coli strains isolated from pigs suffering diarrhea (n = 94) and pigs without diarrhea (n = 28) of 24 farms in Spain. Virulence factors, toxins and AMR (ESBL and colistin) genes and AMR phenotypes of E. coli isolates were analyzed. Low prevalence of pathogenic E. coli strains (26%) was found in both groups. However, ETEC and VTEC strains were more frequently isolated from diarrheic piglets. Irrespectively of diarrhea occurrence, 97.5% of the strains showed a multidrug-resistance (MDR) profile to aminopenicillins, sulfonamides and tetracyclines. It was found that 22% of E. coli was CTX-M+, with CTX-M-14 being the principal allelic variant. Remarkably, 81.5% of CTX-M+ strains were isolated from diarrheic animals and presented an extended MDR profile to aminopenicillins, quinolones and aminoglycosides. Finally, low frequencies of colistin resistance genes mcr-1 (4/122) and mcr-4 (1/122) were found. MDR E. coli strains are circulating in pig farms of Spain, representing a serious threat to animal and public health. More appropriate diagnostic approaches (genetic and AMR phenotypic analysis) should be implemented in animal health to optimize antibiotic treatments.info:eu-repo/semantics/publishedVersio

Batman Despertar: da Narrativa em Quadrinhos para o Spotify

Presents an analysis about the adaptation of the story of the comic book character Batman for the audio-series format on the Spotify platform, in order to understand how the new technologies and hypermedia relations between the various media are worked in order to meet consumption. of narratives in a society of tiredness and performance, in a clear and simple way, but still challenging to stir up new sensations of a symbol present in popular memory and recognized within Pop culture.Apresenta uma análise a respeito da adaptação da história do personagem de Histórias em Quadrinhos Batman para o formato de áudio-série na plataforma Spotify, para se compreender como as novas tecnologias e relações hipermidiáticas entre os diversos meios são trabalhadas para atender ao consumo de narrativas em uma sociedade do cansaço e de desempenho, de forma clara e simples, mas ainda assim desafiadora em atiçar novas sensações de um símbolo presente na memória popular e reconhecido dentro da cultura Pop.