Intra-unit reliability and movement variability of submission grappling external load as measured by torso mounted accelerometery.

Submission grappling consists of skills and movements used in combat sports to physically control opponents whilst trying to apply choke holds and joint locks. There is currently no accepted method of monitoring external load in grappling-based sports due to the absence of key variables such as distance, velocity or time. The primary aim of this study was to determine whether PlayerLoad is a reliable variable for measuring external load of submission grappling movements, with a secondary aim of determining the between repetition variance of submission grappling movements. 7 experienced submission grapplers were recruited. Each wore a torso mounted Catapult® Optimeye S5 microelectromechanical systems (MEMS) device and completed 5 repetitions of each of the following: 4 submission techniques; 5 transition techniques; 2 guard pass techniques; 2 takedown techniques. Accumulated PlayerLoad (PLdACC) was recorded as a marker of absolute load, with accumulated PlayerLoad per minute (PLdACC∙min-1) representing relative load. Reliability of each was assessed using intraclass correlation coefficient (ICC(3,1)) (≥ 0.70). Between repetition movement variation was assessed via coefficient of variation with 95% confidence intervals (CV, 95%CI) (acceptable ≤ 15%, good ≤ 10%). PLdACC ICC(3,1) range = 0.78-0.98, with CV range = 9-22%. PLdACC∙min-1 ICC(3,1) range = 0.83-0.98, with CV range = 11-19%. Though several variables displayed CV > 15%, all had 95%CI lower boundaries ≤ 15%. Whilst PlayerLoad was found to be a reliable measure for submission grappling, relatively high CVs across most techniques examined suggest PlayerLoad may not be appropriate for measuring changes in external load for individual movements in submission grappling. However, it may prove a useful tool for monitoring the external load of full, grappling-based, training sessions within an individual.

Ventricular structure, function, and focal fibrosis in anabolic steroid users: a CMR study.

PURPOSE: Anabolic steroid (AS) misuse is widespread amongst recreational bodybuilders; however, their effects on the cardiovascular system are uncertain. Our aim was to document the impact of AS use on cardiac structure, function and the presence of focal fibrosis using the gold standard cardiovascular magnetic resonance imaging (CMR). METHODS: A cross-sectional cohort design was utilised with 21 strength-trained participants who underwent CMR imaging of the heart and speckle-tracking echocardiography. Thirteen participants (30 ± 5 years) taking AS for at least 2 years and currently on a "using"-cycle were compared with age and training-matched controls (n = 8; 29 ± 6 years) who self-reported never having taken AS (NAS). RESULTS: AS users had higher absolute left ventricular (LV) mass (220 ± 45 g) compared to NAS (163 ± 27 g; p < 0.05) but this difference was removed when indexed to fat-free mass. AS had a reduced right ventricular (RV) ejection fraction (AS 51 ± 4 % vs. NAS 59 ± 5 %; p < 0.05) and a significantly lower left ventricular E':A' myocardial tissue velocity ratio [AS 0.99(0.54) vs. NAS 1.78(0.46) p < 0.05] predominantly due to greater tissue velocities with atrial contraction. Peak LV longitudinal strain was lower in AS users (AS -14.2 ± 2.7 % vs. NAS -16.6 ± 1.9 %; p < 0.05). There was no evidence of focal fibrosis in any participant. CONCLUSIONS: AS use was associated with significant LV hypertrophy, albeit in-line with greater fat-free mass, reduced LV strain, diastolic function, and reduced RV ejection fraction in male bodybuilders. There was, however, no evidence of focal fibrosis in any AS user.

Performance enhancing drug abuse and cardiovascular risk in athletes: implications for the clinician.

The use of performance-enhancing and social drugs by athletes raises a number of ethical and health concerns. The World Anti-Doping Agency was constituted to address both of these issues as well as publishing a list of, and testing for, banned substances in athletes. Despite continuing methodological developments to detect drug use and associated punishments for positive dope tests, there are still many athletes who choose to use performance and image enhancing drugs. Of primary concern to this review are the health consequences of drug use by athletes. For such a large topic we must put in place delimitations. Specifically, we will address current knowledge, controversies and emerging evidence in relation to cardiovascular (CV) health of athletes taking drugs. Further, we delimit our discussion to the CV consequences of anabolic steroids and stimulant (including amphetamines and cocaine) use. These drugs are reported in the majority of adverse findings in athlete drug screenings and thus are more likely to be relevant to the healthcare professionals responsible for the well-being of athletes. In detailing CV health issues related to anabolic steroid and stimulant abuse by athletes we critique current research evidence, present exemplar case studies and suggest important avenues for on-going research. Specifically we prompt the need for awareness of clinical staff when assessing the potential CV consequences of drug use in athletes.

Mathematical modelling of metabolic regulation in aging.

The underlying cellular mechanisms that characterize aging are complex and multifaceted. However, it is emerging that aging could be regulated by two distinct metabolic hubs. These hubs are the pathway defined by the mammalian target of rapamycin (mTOR) and that defined by the NAD+-dependent deacetylase enzyme, SIRT1. Recent experimental evidence suggests that there is crosstalk between these two important pathways; however, the mechanisms underpinning their interaction(s) remains poorly understood. In this review, we propose using computational modelling in tandem with experimentation to delineate the mechanism(s). We briefly discuss the main modelling frameworks that could be used to disentangle this relationship and present a reduced reaction pathway that could be modelled. We conclude by outlining the limitations of computational modelling and by discussing opportunities for future progress in this area.

Anabolic steroid use and longitudinal, radial, and circumferential cardiac motion.

PURPOSE: The purpose of this study was to investigate the effect of anabolic steroid (AS) use on cardiac structure and function and cardiovascular risk factors. METHODS: We recruited 47 strength-trained individuals (male = 46, female = 1), with 28 self-reporting regular AS use and 19 self-reporting never taking AS. Participants underwent assessment of body composition, lipid profiles, blood pressure, 12-lead ECG, and a comprehensive echocardiographic examination incorporating speckle tracking of longitudinal, radial, and circumferential left ventricular (LV) motion. A subgroup of AS users (n = 4) were tested during periods of AS use and abstinence. RESULTS: AS users were heavier (96 ± 15 vs 81 ± 9 kg, P < 0.05), had higher LDL (3.68 ± 0.47 vs 2.41 ± 0.49 mmol·L⁻¹, P < 0.05), and had higher resting HR (79 ± 12 vs 64 ± 13 beats·min⁻¹), although blood pressures did not differ significantly between groups. In AS, LV wall thickness and mass were significantly greater (12 ± 2 vs 11 ± 1 mm and 280 ± 60 vs 231 ± 44 g, respectively, P < 0.05), whereas ejection fractions and peak longitudinal strain ([Latin Small Letter Open E]) were significantly lower (58% ± 8% vs 63% ± 6% and -14.6% ± 2.3% vs -16.9% ± 2.2%, P < 0.05). Indices of global diastolic function were reduced in AS users (E/A, E'/A'). Some diastolic strain rates (ESR and ASR) were altered in AS users. The E/A SR ratio was reduced in the longitudinal plane as well as in the circumferential and radial plane at the basal level (P < 0.05). Basal LV E/A rotation rate was also decreased in AS users (P < 0.05). CONCLUSIONS: AS use is associated with alterations in cardiac structure and function that, allied to poor lipid profiles, represent an increased cardiovascular risk profile.