Sports biomechanics: monitoring health and performance

Biomechanics is part of biophysics and aims to study the function and structure of biological systems based on the principles, laws, and methods of mechanics. The human body is a dynamic system in constant change, with internal (physiological) and external effects (mechanical). From an external point of view, every action/movement results from forces produced by the subject and by external forces acting on him/her. The study of these forces and their effects, such as movement, absence of movement, and deformations is the main focus of biomechanics. The amount of forces that act on the human system in each movement will also result in an internal response, so the higher the mechanical stress, the greater the physiological impact [1]. This association is observed in every physical or sports activity, highlighting the importance of biomechanics for a better understanding of the physiological response to exercise [2, 3]. When a sports professional is concerned by how the available energy is used to exercise at a specific intensity/volume, causing a chain of intersegmental movements, he/she is facing biomechanical issues. The boundary of the object of study between biomechanics and physiology in sport is so tangential that it is sometimes confused [4, 5]. In this way, biomechanical analysis can help to control physical demands and explain the athlete’s state of well-being [6]. Therefore, it will play an important role in sports performance and the participants’ health, in which mechanics and physiology are combined in sports biomechanics [7].This work was supported Portuguese Foundation for Science and Technology, I.P. (project UIDB/04045/2021).info:eu-repo/semantics/publishedVersio

Comparison of the start, turn and finish performance of elite swimmers in 100 m and 200 m races

The main aim of this study was to compare the start, turn, and finish performance of 100 m and 200 m events in the four swimming strokes in elite swimmers of both sexes. The performances of all 128 finalists (64 males and 64 females) of the 100 m, and 200 m events at a major championship were analyzed. A set of variables related to the start, turn, and finish were assessed. In the start a significant and moderate race effect was verified in both sexes (100 m vs 200 m). It was highest in butterfly events (males: Δ = 9.81%, p = 0.046, η2 = 0.60; females: Δ = 7.96%, p < 0.001, η2 = 0.75). In the turn a significant and moderate-strong race effect was verified in all strokes in both sexes, the highest being in butterfly (males: Δ = 12.26%, p < 0.001, η2 = 0.93; females: Δ = 10.74%, p < 0.001, η2 = 0.92). The finish had a significant and moderate race effect in butterfly and in breaststroke (females). The underwater variables were found to be the main contributors to a faster start. Over the turn, key determinants were the surface variables. As for the finish, mixed results were observed. It can be suggested that the underwater profile was the main determinant in starting, whereas the surface profile was the main determinant in turning. Therefore, coaches are advised to focus on such race phases to enhance the total race time.Our thanks to LEN and Spiideo AB for providing the video clips. This work is supported by national funding through the Portuguese Foundation for Science and Technology, I.P., under project UIDB/04045/2020. We would also like to thank the University of Beira Interior and Santander Universities (Bolsa BIPD/ICIFCSH-Santander Universidades-UBI/2017) for their support. The experiments comply with the current laws of the country in which they were performed. The authors have no conflict of interest to declare.info:eu-repo/semantics/publishedVersio

Análise dos Fatos utilizados no 13º Campeonato do Mundo FINA

Para nadar mais rápido, é necessário aumentar a propulsão e diminuir o arrasto. Para o caso, os fatos de natação de poliuretano podem ter desempenhado um papel importante (Marinho et al., 2009). Com este estudo pretende-se descrever a distribuição dos diferentes modelos de fatos de natação usados pelos nadadores durante todas as finais do 13º Campeonato do Mundo de natação, realizado em Roma e assim perceber as preferências dos nadadores de elevado nível desportivo

Three-Port Laparoscopic Cholecystectomy in a Brazilian Amazon Woman with Situs Inversus Totalis: Surgical Approach

Situs inversus totalis (SIT) is an uncommon anomaly characterized by transposition of organs to the opposite side of the body in a mirror image of normal. We report on an adult woman, born and resident in Brazilian Amazonia, presenting acute pain located at the left hypochondrium and epigastrium. During clinical and radiological evaluation, the patient was found to have SIT and multiple stones cholelithiasis. Laparoscopic cholecystectomy was safely performed with the three-port technique in a reverse fashion. In conclusion, this case confirms that three-port laparoscopic cholecystectomy is a safe and feasible surgical approach to treat cholelithiasis even in rare and challenging conditions like SIT

The drag crisis phenomenon on an elite road cyclist: a preliminary numerical simulations analysis in the aero position at different speeds

The drag crisis phenomenon is the drop of drag coefficient (Cd) with increasing Reynolds number (Re) or speed. The aim of this study was to assess the hypothetical drag crisis phenomenon in a sports setting, assessing it in a bicycle–cyclist system. A male elite-level cyclist was recruited for this research and his competition bicycle, helmet, suit, and shoes were used. A three-dimensional (3D) geometry was obtained with a 3D scan with the subject in a static aero position. A domain with 7 m of length, 2.5 m of width and 2.5 m of height was created around the cyclist. The domain was meshed with 42 million elements. Numerical simulations by computer fluid dynamics (CFD) fluent numerical code were conducted at speeds between 1 m/s and 22 m/s, with increments of 1 m/s. The drag coefficient ranged between 0.60 and 0.95 across different speeds and Re. The highest value was observed at 2 m/s (Cd = 0.95) and Re of 3.21 × 105, whereas the lower Cd was noted at 9 m/s (Cd = 0.60) and 9.63 × 105. A drag crisis was noted between 3 m/s and 9 m/s. Pressure Cd ranged from 0.35 to 0.52 and the lowest value was observed at 3m/s and the highest at 2 m/s. The viscous drag coefficient ranged between 0.15 and 0.43 and presented a trend decreasing from 4 m/s to 22 m/s. Coaches, cyclists, researchers, and support staff must consider that Cd varies with speed and Re, and the bicycle–cyclist dimensions, shape, or form may affect drag and performance estimations. As a conclusion, this preliminary work noted a drag crisis between 3 m/s and 9 m/s in a cyclist in the aero positionThis research is supported by the Portuguese Foundation for Science and Technology, I.P. (project UIDB04045/2020) and The APC was funded by Research Center in Sports Health and Human Development, Covilhã, Portugal.info:eu-repo/semantics/publishedVersio

13th FINA world Championship: analysis of swimsuits used by elite male swimmers

The polyurethane swimsuits has become the notice around the pools in the past couple years. A better body position and the reducing of drag are believed to be some of the reasons that allow the swimmers wearing these swimsuits to go faster (Kainuma et al., 2009). The purpose of this study was to verify the distribution of different swimsuits used by male swimmers during the finals at the last world championships being held at Rome in 200

Doença Inflamatória Intestinal Pediátrica cada vez mais comum

Regular landscape patterning arises from spatially-dependent feedbacks, and can undergo catastrophic loss in response to changing landscape drivers. The central Everglades (Florida, USA) historically exhibited regular, linear, flow-parallel orientation of high-elevation sawgrass ridges and low-elevation sloughs that has degraded due to hydrologic modification. In this study, we use a meta-ecosystem approach to model a mechanism for the establishment, persistence, and loss of this landscape. The discharge competence (or self-organizing canal) hypothesis assumes non-linear relationships between peat accretion and water depth, and describes flow-dependent feedbacks of microtopography on water depth. Closed-form model solutions demonstrate that 1) this mechanism can produce spontaneous divergence of local elevation; 2) divergent and homogenous states can exhibit global bi-stability; and 3) feedbacks that produce divergence act anisotropically. Thus, discharge competence and non-linear peat accretion dynamics may explain the establishment, persistence, and loss of landscape pattern, even in the absence of other spatial feedbacks. Our model provides specific, testable predictions that may allow discrimination between the self-organizing canal hypotheses and competing explanations. The potential for global bi-stability suggested by our model suggests that hydrologic restoration may not re-initiate spontaneous pattern establishment, particularly where distinct soil elevation modes have been lost. As a result, we recommend that management efforts should prioritize maintenance of historic hydroperiods in areas of conserved pattern over restoration of hydrologic regimes in degraded regions. This study illustrates the value of simple meta-ecosystem models for investigation of spatial processes

Topological Homogeneity for Electron Microscopy Images

In this paper, the concept of homogeneity is defined, from a topological perspective, in order to analyze how uniform is the material composition in 2D electron microscopy images. Topological multiresolution parameters are taken into account to obtain better results than classical techniques.Ministerio de Economía y Competitividad MTM2016-81030-PMinisterio de Economía y Competitividad TEC2012-37868-C04-0

Marine forests of the Mediterranean-Atlantic Cystoseira tamariscifolia complex show a southern Iberian genetic hotspot and no reproductive isolation in parapatry

Climate-driven range-shifts create evolutionary opportunities for allopatric divergence and subsequent contact, leading to genetic structuration and hybrid zones. We investigate how these processes influenced the evolution of a complex of three closely related Cystoseira spp., which are a key component of the Mediterranean-Atlantic seaweed forests that are undergoing population declines. The C. tamariscifolia complex, composed of C. tamariscifolia s.s., C. amentacea and C. mediterranea, have indistinct boundaries and natural hybridization is suspected. Our aims are to (1) infer the genetic structure and diversity of these species throughout their distribution ranges using microsatellite markers to identify ancient versus recent geographical populations, contact zones and reproductive barriers, and (2) hindcast past distributions using niche models to investigate the influence of past range shifts on genetic divergence at multiple spatial scales. Results supported a single, morphologically plastic species the genetic structure of which was incongruent with a priori species assignments. The low diversity and low singularity in northern European populations suggest recent colonization after the LGM. The southern Iberian genetic hotspot most likely results from the role of this area as a climatic refugium or a secondary contact zone between differentiated populations or both. We hypothesize that life-history traits (selfing, low dispersal) and prior colonization effects, rather than reproductive barriers, might explain the observed genetic discontinuities.Pew Charitable Trusts (USA); MARINERA, Spain [CTM2008-04183-E/MAR]; FCT (Portugal) [FCT-BIODIVERSA/004/2015, CCMAR/Multi/04326/2013, SFRH/BPD/107878/2015, SFRH/BPD/85040/2012]; FPU fellowship of the Spanish Ministry of Education; European Community ASSEMBLE visiting grant [00399/2012]; University of Cadi