Lawn Tennis Association

Tennis is one of the sports that requires a high level of physical requirements, including speed, agility, strength, endurance, power, flexibility, footwork, and hand-eye coordination, just to successfully serve or receive a ball. In Malaysia, a total of 13 different tournaments, organized locally, and internationally, are available for young tennis athletes to participate in, where they are required to attend various scheduled and intensive training sessions prior to their tournament, ranging from 12 to 48 hours per month in different age groups. Given the chronic stressors including high training load, academic demands, and expectations from coaches, family, and the athletes themselves, young tennis athletes are predisposed to overtraining and burnout occurrence. Overtraining is defined as a longer period of negative unintentional consequences of training, resulting in decreased performance, which lasts longer than just a few days. Burnout is defined as a psychophysiological response to exhaustion, involving three components, including psychological, physical, and behavioural components, which manifests in three features including emotional and physical exhaustion, reduced sense of accomplishment and sport devaluation. Hence, this study aims to identify the risk factors of burnout and overtraining in young tennis athletes, to provide actionable recommendations to parents, coaches, and paediatricians, and in supporting young athletes’ well- being. A total of five articles which studies the correlation between training load or training volume and occurrence of burnout in young tennis athletes were included in this study. Results yielded were inconclusive to recommend the optimum duration of recommended training hours or training load in young tennis athletes, to avoid the occurrence of burnout, highlighting the need for further research to be conducted to establish the relationship between training load and burnout occurrence in young tennis players in Malaysia.

Oedema occurs when higher than normal amounts of solutes and water accumulate in tissues. In brain parenchymal tissue, vasogenic oedema arises from changes in blood–brain barrier permeability, e.g. in peritumoral oedema. Cytotoxic oedema arises from excess accumulation of solutes within cells, e.g. ischaemic oedema following stroke. This type of oedema is initiated when blood flow in the affected core region falls sufficiently to deprive brain cells of the ATP needed to maintain ion gradients. As a consequence, there is: depolarization of neurons; neural uptake of Na+ and Cl− and loss of K+; neuronal swelling; astrocytic uptake of Na+, K+ and anions; swelling of astrocytes; and reduction in ISF volume by fluid uptake into neurons and astrocytes. There is increased parenchymal solute content due to metabolic osmolyte production and solute influx from CSF and blood. The greatly increased [K+]isf triggers spreading depolarizations into the surrounding penumbra increasing metabolic load leading to increased size of the ischaemic core. Water enters the parenchyma primarily from blood, some passing into astrocyte endfeet via AQP4. In the medium term, e.g. after three hours, NaCl permeability and swelling rate increase with partial opening of tight junctions between blood–brain barrier endothelial cells and opening of SUR1-TPRM4 channels. Swelling is then driven by a Donnan-like effect. Longer term, there is gross failure of the blood–brain barrier. Oedema resolution is slower than its formation. Fluids without colloid, e.g. infused mock CSF, can be reabsorbed across the blood–brain barrier by a Starling-like mechanism whereas infused serum with its colloids must be removed by even slower extravascular means. Large scale oedema can increase intracranial pressure (ICP) sufficiently to cause fatal brain herniation. The potentially lethal increase in ICP can be avoided by craniectomy or by aspiration of the osmotically active infarcted region. However, the only satisfactory treatment resulting in retention of function is restoration of blood flow, providing this can be achieved relatively quickly. One important objective of current research is to find treatments that increase the time during which reperfusion is successful. Questions still to be resolved are discussed.

Wheelchair tennis, a globally popular sport, features a professional tour spanning 40 countries and over 160 tournaments. Despite its widespread appeal, information about the physical demands of wheelchair tennis is scattered across various studies, necessitating a comprehensive systematic review to synthesise available data. The aim was to provide a detailed synthesis of the physical demands associated with wheelchair tennis, encompassing diverse factors such as court surfaces, performance levels, sport classes, and sexes. We conducted comprehensive searches in the PubMed, Embase, CINAHL, and SPORTDiscus databases, covering articles from inception to March 1, 2023. Forward and backward citation tracking from the included articles was carried out using Scopus, and we established eligibility criteria following the Population, Exposure, Comparison, Outcome, and Study design (PECOS) framework. Our study focused on wheelchair tennis players participating at regional, national, or international levels, including both juniors and adults, and open and quad players. We analysed singles and doubles matches and considered sex (male, female), sport class (open, quad), and court surface type (hard, clay, grass) as key comparative points. The outcomes of interest encompassed play duration, on-court movement, stroke performance, and physiological match variables. The selected study designs included observational cross-sectional, longitudinal, and intervention studies (baseline data only). We calculated pooled means or mean differences with 95% confidence intervals (CIs) and employed a random-effects meta-analysis with robust variance estimation. We assessed heterogeneity using Cochrane Q and 95% prediction intervals. Our literature search retrieved 643 records, with 24 articles meeting our inclusion criteria. Most available information focused on international male wheelchair tennis players in the open division, primarily competing in singles on hard courts. Key findings (mean [95% CI]) for these players on hard courts were match duration 65.9min [55.0-78.8], set duration 35.0min [28.2-43.5], game duration 4.6min [0.92-23.3], rally duration 6.1s [3.7-10.2], effective playing time 19.8% [18.9-20.7], and work-to-rest ratio 1:4.1 [1:3.7-1:4.4]. Insufficient data were available to analyse play duration for female players. However, for the available data on hard court matches, the average set duration was 34.8min [32.5-37.2]. International male players on hard court covered an average distance per match of 3859m [1917-7768], with mean and peak average forward speeds of 1.06m/s [0.85-1.32] and 3.55m/s [2.92-4.31], respectively. These players executed an average of 365.9 [317.2-422.1] strokes per match, 200.6 [134.7-299.0] per set, 25.4 [16.7-38.7] per game, and 3.4 [2.6-4.6] per rally. Insufficient data were available for a meta-analysis of female players' on-court movement and stroke performance. The average and peak heart rates of international male players on hard court were 134.3 [124.2-145.1] and 166.0 [132.7-207.6] beats per minute, and the average match heart rate expressed as a percentage of peak heart rate was 74.7% [46.4-100]. We found no studies concerning regional players or juniors, and only one study on doubles match play. While we present a comprehensive overview of the physical demands of wheelchair tennis, our understanding predominantly centres around international male players competing on hard courts in the open division. To attain a more comprehensive insight into the sport's physical requirements, future research should prioritise the inclusion of data on female and quad players, juniors, doubles, and matches played on clay and grass court surfaces. Such endeavours will facilitate the development of more tailored and effective training programmes for wheelchair tennis players and coaches. The protocol for this systematic review was registered a priori at the International Platform of Registered Systematic Review and Meta-analysis Protocols (Registration https://doi.org/10.37766/inplasy2023.3.0060 ).

ABSTRACT The aim of this research was to analyse the differences in performance indicators between outdoor and indoor professional padel tournaments according to the gender of the players, the round in the draw, the set number, and their result. Performance indicators (winning break points, errors, winning shots, winning smashes…) of 942 sets (402 matches) from the 2022 World Padel Tour (WPT) season were collected from WPT TV open access videos. Differences between outdoor and indoor tournaments in performance indicators according to the analysed variables were analysed through descriptive and inferential statistics. The results showed significant differences between outdoor and indoor tournaments in men’s padel with a higher number of winning shots (p < 0.001) in indoor matches, and in women’s padel with a higher number of smashes (p < 0.001), winning smashes (p = 0.003) and errors (p = 0.002), in outdoor matches. In addition, the rounds in the draw, the set number, and its result were found to be parameters that influence the performance indicators analysed according to the tournament (outdoor and indoor). These findings are of great interest, as they provide players and coaches with an understanding of the performance indicators that affect the style of play depending on whether the tournament is played outdoors or indoors.

In this article, we look at how competition is presented in the traditional mini tennis lesson, finding that it typically occurs once, at the end of the session. We then explore some of the limitations associated with competition in this format. Following that, we discuss the importance of developing competitive capabilities, and propose an alternative way of approaching the mini tennis lesson to provide more opportunity for competition while systematically developing tactical and technical skills in a manner consistent with findings from skill acquisition research. This methodological approach, we suggest, provides a more fertile environment in which to develop competitive performers alongside the tactical and technical performance factors.

Abstract Tissue homeostasis is maintained by the behaviours of lymphocyte clones responding to antigenic triggers in the face of pathogen, environmental, and developmental challenges. Current methodologies for tracking the behaviour of specific lymphocytes identify clones of a defined antigen-receptor—antigen binding affinity. However, lymphocytes can receive antigenic signals from undefined or endogenous antigens, and the strength of each signal, even for the same lymphocyte, varies with accessory signalling, across tissues and across time. We present a novel fate-mapping mouse, that, by tracking lymphocyte clones and their progenies from induced antigen signals, overcomes these hurdles and provides novel insights into the maintenance of tissue homeostasis. We demonstrate the systems use by investigating the maintenance of localised T cell tolerance in tumour immunity. In a murine tumour model, our system reveals how Tregs differentiate to a reversible, tolerance inducing state within the tumour, and recirculate, while CD8+ T cells failing to recirculate, differentiate to an increasingly exhausted, tolerant state in the tumour. These contrasting T cell behaviours provide means by which immunity can tolerate a particular anatomical niche while maintaining systemic clonal protection. Our system can thus explore lymphocyte behaviours that cannot be tracked by previous methods and will therefore provide novel insights into the fundamental mechanisms underlying immunity’s role in tissue homeostasis.

As in mammals, only one cell in a Drosophila multicellular female germline cyst is specified as an oocyte. The symmetry-breaking cue for oocyte selection is provided by the fusome, a tubular structure connecting all cells in the cyst. The Drosophila spectraplakin Shot localises to the fusome and translates its asymmetry into a polarised microtubule network that is essential for oocyte specification, but how Shot recognises the fusome is unclear. Here we demonstrate that Shot's actin-binding domain (ABD) is necessary and sufficient to localise Shot to the fusome and mediates Shot function in oocyte specification together with the microtubule-binding domains. The calponin homology domain 1 (CH1) of Shot's ABD recognises fusomal F-actin and requires CH2 to distinguish it from other forms of F-actin in the cyst. By contrast, the ABDs of Utrophin, Fimbrin, Filamin, Lifeact and F-tractin do not recognise fusomal F-actin. We therefore propose that Shot propagates fusome asymmetry by recognising a specific conformational state of F-actin on the fusome.

This study uses self-determination and flow theories as a theoretical framework to investigate the role of need for competence satisfaction (NCS) and autonomous motivation (AM) in balance between challenge and skills (BCS) and dispositional flow (DF) in international junior elite tennis players. A sample of 114 (62 girls and 52 boys) junior elite players (15.62 ± 1.36 years) representing 24 countries competing in International Tennis Federation junior tournaments completed measures on the NCS using the Basic Needs Satisfaction in Sport Scale, AM with the Sport Motivation Scale and DF State scale to measure the BCS and their DF. Values of Cronbach α &gt;.80 and the rhô Jöreskog coefficients were shown to be satisfactory and &gt;0.89. The independent sample t-test analysis revealed no significant gender differences in any of them ( p &gt; .05). Simple regression analysis showed that there was a significant positive linear correlation between BCS and DF (r = .46; F = 29.31, p &lt; .001). Multiple regression analysis indicated that AM and NCS explained 50.8% of the variance of BCS (F = 57.30, p &lt; .001). Canonical correlation analysis indicated that a lack of NCS and AM was associated with a lack of DF and BCS. Wilks’ lambda = .38, F = 34.11, p &lt; .001, accounted for 99% (rc = .79) of the overlapping variance. It can be concluded that NCS and AM contribute effectively to the BCS and then to DF in the sample studied.

Abstract Leucine-rich repeat-containing G-protein receptor 5 (LGR5) has been characterised as a stem cell and cancer stem cell marker. Previous analyses of LGR5 transcript levels indicate high level expression discriminates malignancies such as colorectal cancer (CRC) and pre-B acute lymphoblastic leukaemia (pre-B ALL) from healthy tissues suggesting LGR5 protein expression may provide a molecular handle for prognosis and treatment.We have developed highly specific, high affinity antibodies to the extracellular domain of human LGR5 (α-LGR5) that detect high LGR5 protein levels in colorectal cancer (CRC), hepatocellular carcinoma (HCC), and pre-B ALL. In contrast, there is low to undetectable levels of LGR5 protein in normal colon and rectal epithelia, liver, ovarian tissues, brain and immune cell types.LGR5 is rapidly internalised from the plasma membrane and trafficked to intracellular vesicular compartments including lysosomes. Treatment of high LGR5-expressing CRC and pre-B ALL cancer cell lines with an antibody-drug conjugate version of α-LGR5 (α-LGR5-ADC) lead to effective cell killing at nanomolar concentrations. Interventional treatment of pre-B ALL tumours with α-LGR5-ADC in vivo led to rapid tumour attrition. We further demonstrated the therapeutic utility of humanised α-LGR5 by using the corresponding scFv fragment for the generation of α-LGR5 chimeric antigen receptors (CARs) and a Bispecific T cell Engager (BiTE). α-LGR5-CAR-NK cells were effective at killing LGR5-expressing cells while α-LGR5/α-CD3 BiTEs induce T cell activation and killing of NALM6 cells by cytotoxic CD8+ T cells.Taken together, this study establishes α-LGR5-based therapeutic modalities that effectively discriminate and target CRC, HCC and pre-B ALL tumour cells.One Sentence SummaryWe generated novel antibodies against the cancer cell marker LGR5, validated diagnostic use in prioritizing specific cancer types for targeting, and developed antibody-based therapeutics.