The manifestations of fatigue in amateur boxing performance

A subjective method of judgment, the “Ten Point Must-System” (TPMS), was introduced into amateur boxing in 2013. To be successful, boxers must deliver forceful punches and exert dominance over an opponent. There has been limited research examining the strategies used by boxers to win fights under the TPMS and whether these strategies induce fatigue that is sufficient to significantly affect punch force. The overall objective of the five studies contained in this thesis was to describe, in relation to fatigue, the performance characteristics of male amateur boxers under the TPMS, and improve our understanding of the physical characteristics associated with punch force production in highly-trained male amateur boxers. The first study describes technical and behavioural patterns as well as perceptions of effort and fatigue in winning and losing boxers during competition bouts. Winners were found to punch more accurately than losers (33% vs. 23% of punches were landed and 17% vs. 27% were air punches) but the total number of punches were similar. Clinch time, guard drops, and perceptions of effort and fatigue all increased, and bouncing decreased in all boxers over rounds. Regression analysis revealed that in combination, the percentage of punches landed and movement style correctly classified 85% of bout outcomes. Boxers appear to use tactical strategies throughout bouts to pace their effort and minimise fatigue, but these did not influence bout outcome. Thus, judges use several performance indicators, including punch accuracy (but not number) and movement style to (subjectively) assess dominance and determine a winner. To understand the interaction between punch force and fatigue-related behaviour, a boxingspecific, laboratory-based test (3-min punch test; 3MPT) was designed to measure punch force (N) and force-time variables (i.e. impulse and various rate of force development variables; RFD). The punch force measurement system had high mechanical reliability and accuracy (CV \u3c 0.1%). Typical error and smallest worthwhile changes comparisons revealed that the 3MPT could detect moderate and large changes in performance, however within-day reliability improved from day 1 - 2 (CVs of 3.1 - 13.8% vs. 2.3 - 5.1%), indicating a possible learning effect. Thus, repeat-trial familiarisation is suggested to reduce between-test variability. Studies 3 - 5 then utilised this system to examine factors that may influence punch force delivery. In Study 3, correlation and regression analyses revealed significant (p \u3c 0.05) relationships between peak punch force and forces measured in countermovement jump and isometric mid thigh pull tests (i.e. lower-body strength) as well as body mass, but not RFD, in the lower body. No meaningful relationships between punch performance characteristics and any upper-body strength or power parameters were identified. The results of Study 3 show lower-body strength, but not RFD was significantly and positively related to peak punch force, however upper-body strength and power did not discriminate between boxers who punched with higher or lower peak force. In Study 4, punch force characteristics, were measured in the 3MPT of highlytrained male amateur boxers before (ROWpre) and after (ROWpost) 9 × 1-min bouts of rowing. This was designed to induce fatigue in lower limb, trunk, and arm flexion muscles whilst leaving arm extensor muscles (primary punch muscles) non-fatigued. Significant reductions in punch force were found ROWpost compared to ROWpre for all punch types, and significant delays in the time to reach specific force levels and relative percentages of peak force (i.e. RFD) occurred in all punches except the jab. Thus, punches that particularly rely on lower-limb force production and trunk rotation (crosses and hooks) were most affected. Speculatively, ground reaction force generation was affected by fatigue, however since the jab relies predominantly on arm extension, punch force was less affected by lower-limb fatigue. In Study 5, the effect of non-specific muscle fatigue (rowing; ROW; as described in Study 4) on punch force production was also examined using the 3MPT, with additional comparisons between control (CON; 75 min rest) and boxing (BOX; competitive boxing bout [3 × 3 min]) conditions in a population of highly-trained male amateur boxers. Significant punch force reductions from ROWpre to ROWpost in lead-hand hooks and jabs were observed, however no significant differences were present in CON or BOX, and RFD variables remained unchanged in all conditions. These results suggest that reductions in punch performance after rowing arise from fatigue in the lower body and trunk muscles, whilst boxing is likely to cause fatigue in other body segments that have less influence on punch force production; it is also speculated that boxers use pacing strategies to maintain punch force during fatiguing boxing bouts. The general findings of this thesis were: technical and behavioural (possibly altered by fatigue) actions influence judge perception under the TPMS, and success requires high levels of punch accuracy; lower-body (but not upper-body) strength rather than RFD was associated with punch force production; lower-body and trunk fatigue significantly reduced punch force, supporting the theory lower-body strength is important to produce punch force; and, boxers maintained the ability to produce punch force throughout a boxing bout, possibly because fatigue was not accumulated in the lower limb and trunk muscles (partly due to boxers using pacing strategies)

DISTRIBUTION AND MOVEMENTS OF BOTTLENOSE DOLPHINS (TURSIOPS TRUNCATUS) ALONG THE NORTHERN SOUTH CAROLINA COAST: A RESEARCH PARTNERSHIP WITH ECOTOURISM

Assessments of bottlenose dolphin stocks rely on current information about the distribution and abundance of specific populations. We partnered with two ecotourism dolphin watch businesses to investigate bottlenose dolphins along the northern South Carolina coast. The temporal and spatial distribution of dolphins was examined by comparing dorsal fin images from research-based surveys with photo-identification efforts from commercial dolphin watch groups. Matches between survey locations and times revealed patterns of seasonal residency, potential migratory dispersal between seasons, and variable patterns for home range size. An enhanced understanding of the structure of local populations will contribute to the management of local fisheries, ecotour operations, and coastal ocean health

Compound-specific amino acid isotopic proxies for detecting freshwater resource consumption

AbstractOf central importance to palaeodietary reconstruction is a clear understanding of relative contributions of different terrestrial (i.e., C3 vs. C4 plants) and aquatic (i.e., freshwater vs. marine) resources to human diet. There are, however, significant limitations associated with the ability to reconstruct palaeodiet using bulk collagen stable isotope compositions in regions where diverse dietary resources are available. Recent research has determined that carbon-isotope analysis of individual amino acids has considerable potential to elucidate dietary protein source where bulk isotopic compositions cannot. Using δ13CAA values for human and faunal remains from Zvejnieki, Latvia (8th – 3rd millennia BCE), we test several isotopic proxies focused on distinguishing freshwater protein consumption from both plant-derived and marine protein consumption. We determined that the Δ13CGly-Phe and Δ13CVal-Phe proxies can effectively discriminate between terrestrial and aquatic resource consumption, and the relationship between essential δ13CAA values and the Δ13CGly-Phe and Δ13CVal-Phe proxies can differentiate among the four protein consumption groups tested here. Compound-specific amino acid carbon-isotope dietary proxies thus enable an enhanced understanding of diet and resource exploitation in the past, and can elucidate complex dietary behaviour

The developmental biology of <i>Charnia</i> and the eumetazoan affinity of the Ediacaran rangeomorphs.

Molecular timescales estimate that early animal lineages diverged tens of millions of years before their earliest unequivocal fossil evidence. The Ediacaran macrobiota (~574 to 538 million years ago) are largely eschewed from this debate, primarily due to their extreme phylogenetic uncertainty, but remain germane. We characterize the development of Charnia masoni and establish the affinity of rangeomorphs, among the oldest and most enigmatic components of the Ediacaran macrobiota. We provide the first direct evidence for the internal interconnected nature of rangeomorphs and show that Charnia was constructed of repeated branches that derived successively from pre-existing branches. We find homology and rationalize morphogenesis between disparate rangeomorph taxa, before producing a phylogenetic analysis, resolving Charnia as a stem-eumetazoan and expanding the anatomical disparity of that group to include a long-extinct bodyplan. These data bring competing records of early animal evolution into closer agreement, reformulating our understanding of the evolutionary emergence of animal bodyplans

Integrin-mediated traction force enhances paxillin molecular associations and adhesion dynamics that increase the invasiveness of tumor cells into a three-dimensional extracellular matrix.

Metastasis requires tumor cells to navigate through a stiff stroma and squeeze through confined microenvironments. Whether tumors exploit unique biophysical properties to metastasize remains unclear. Data show that invading mammary tumor cells, when cultured in a stiffened three-dimensional extracellular matrix that recapitulates the primary tumor stroma, adopt a basal-like phenotype. Metastatic tumor cells and basal-like tumor cells exert higher integrin-mediated traction forces at the bulk and molecular levels, consistent with a motor-clutch model in which motors and clutches are both increased. Basal-like nonmalignant mammary epithelial cells also display an altered integrin adhesion molecular organization at the nanoscale and recruit a suite of paxillin-associated proteins implicated in invasion and metastasis. Phosphorylation of paxillin by Src family kinases, which regulates adhesion turnover, is similarly enhanced in the metastatic and basal-like tumor cells, fostered by a stiff matrix, and critical for tumor cell invasion in our assays. Bioinformatics reveals an unappreciated relationship between Src kinases, paxillin, and survival of breast cancer patients. Thus adoption of the basal-like adhesion phenotype may favor the recruitment of molecules that facilitate tumor metastasis to integrin-based adhesions. Analysis of the physical properties of tumor cells and integrin adhesion composition in biopsies may be predictive of patient outcome

Dual Roles of Fer Kinase Are Required for Proper Hematopoiesis and Vascular Endothelium Organization during Zebrafish Development

Fer kinase, a protein involved in the regulation of cell-cell adhesion and proliferation, has been shown to be required during invertebrate development and has been implicated in leukemia, gastric cancer, and liver cancer. However, in vivo roles for Fer during vertebrate development have remained elusive. In this study, we bridge the gap between the invertebrate and vertebrate realms by showing that Fer kinase is required during zebrafish embryogenesis for normal hematopoiesis and vascular organization with distinct kinase dependent and independent functions. In situ hybridization, quantitative PCR and fluorescence activated cell sorting (FACS) analyses revealed an increase in both erythrocyte numbers and gene expression patterns as well as a decrease in the organization of vasculature endothelial cells. Furthermore, rescue experiments have shown that the regulation of hematopoietic proliferation is dependent on Fer kinase activity, while vascular organizing events only require Fer in a kinase-independent manner. Our data suggest a model in which separate kinase dependent and independent functions of Fer act in conjunction with Notch activity in a divergent manner for hematopoietic determination and vascular tissue organization

Understanding experiences of potential harm among MSM (cis and trans) using HIV self-testing in the SELPHI randomised controlled trial in England and Wales: a mixed-methods study

Background: The potential of HIV self-testing (HIVST) to cause harm is a concern hindering widespread implementation. The aim of this paper is to understand the relationship between HIVST and harm in SELPHI (An HIV Self-testing Public Health Intervention), the largest randomised trial of HIVST in a high-income country to date. Methods: 10 111 cis and trans men who have sex with men (MSM) recruited online (geolocation social/sexual networking apps, social media), aged 16+, reporting previous anal intercourse and resident in England or Wales were first randomised 60/40 to baseline HIVST (baseline testing, BT) or not (no baseline testing, nBT) (randomisation A). BT participants reporting negative baseline test, sexual risk at 3 months and interest in further HIVST were randomised to three-monthly HIVST (repeat testing, RT) or not (no repeat testing, nRT) (randomisation B). All received an exit survey collecting data on harms (to relationships, well-being, false results or being pressured/persuaded to test). Nine participants reporting harm were interviewed in-depth about their experiences in an exploratory substudy; qualitative data were analysed narratively. Results Baseline: predominantly cis MSM, 90% white, 88% gay, 47% university educated and 7% current/former pre-exposure prophylaxis (PrEP) users. Final survey response rate was: nBT=26% (1056/4062), BT=45% (1674/3741), nRT=41% (471/1147), RT=50% (581/1161). Harms were rare and reported by 4% (n=138/3691) in exit surveys, with an additional two false positive results captured in other study surveys. 1% reported harm to relationships and to well-being in BT, nRT and RT combined. In all arms combined, being pressured or persuaded to test was reported by 1% (n=54/3678) and false positive results in 0.7% (n=34/4665). Qualitative analysis revealed harms arose from the kit itself (technological harms), the intervention (intervention harms) or from the social context of the participant (socially emergent harms). Intervention and socially emergent harms did not reduce HIVST acceptability, whereas technological harms did. Discussion: HIVST harms were rare but strategies to link individuals experiencing harms with psychosocial support should be considered for HIVST scale-up

Route knowledge and configural knowledge in typical and atypical development: a comparison of sparse and rich environments

Background: Individuals with Down syndrome (DS) and individuals with Williams syndrome (WS) have poor navigation skills, which impact their potential to become independent. Two aspects of navigation were investigated in these groups, using virtual environments (VE): route knowledge (the ability to learn the way from A to B by following a fixed sequence of turns) and configural knowledge (knowledge of the spatial relationships between places within an environment). Methods: Typically developing (TD) children aged 5 to 11 years (N = 93), individuals with DS (N = 29) and individuals with WS (N = 20) were presented with a sparse and a rich VE grid maze. Within each maze, participants were asked to learn a route from A to B and a route from A to C before being asked to find a novel shortcut from B to C. Results: Performance was broadly similar across sparse and rich mazes. The majority of participants were able to learn novel routes, with poorest performance in the DS group, but the ability to find a shortcut, our measure of configural knowledge, was limited for all three groups. That is, 59 % TD participants successfully found a shortcut, compared to 10 % participants with DS and 35 % participants with WS. Differences in the underlying mechanisms associated with route knowledge and configural knowledge and in the developmental trajectories of performance across groups were observed. Only the TD participants walked a shorter distance in the last shortcut trial compared to the first, indicative of increased configural knowledge across trials. The DS group often used an alternative strategy to get from B to C, summing the two taught routes together. Conclusions: Our findings demonstrate impaired configural knowledge in DS and in WS, with the strongest deficit in DS. This suggests that these groups rely on a rigid route knowledge based method for navigating and as a result are likely to get lost easily. Route knowledge was also impaired in both DS and WS groups and was related to different underlying processes across all three groups. These are discussed with reference to limitations in attention and/or visuo-spatial processing in the atypical groups