The Extra Load Index as a method for comparing the relative economy of load carriage systems

The Extra Load Index (ELI) has been proposed as a suitable method of assessing the relative economy of load carriage systems. The purpose of this study was to determine, based on empirical evidence, that the ELI can accommodate variations in both body composition and added load. In total, 30 women walked carrying loads of up to 70% body mass at self-selected walking speeds whilst expired air was collected. In addition, each of the women had body composition assessed via dual energy X-ray absorptiometry. Results show that the ELI is independent of body composition variables, the magnitude of additional loads and the speed of progression. Consequently, it is suggested that it represents an appropriate method of comparing load carriage systems in both scientific and commercial arenas. Statement of Relevance:This paper demonstrates that ELI is independent of body composition, added load and speed and is therefore an appropriate method to generalise comparisons of load carriage systems. It has the advantage of being easily understood by manufacturers and consumers whilst retaining appropriate scientific precision

Drivers of summer oxygen depletion in the central North Sea

In stratified shelf seas, oxygen depletion beneath the thermocline is a result of a greater rate of biological oxygen demand than the rate of supply of oxygenated water. Suitably equipped gliders are uniquely placed to observe both the supply through the thermocline and the consumption of oxygen in the bottom layers. A Seaglider was deployed in the shallow (≈ 100 m) stratified North Sea in a region of known low oxygen during August 2011 to investigate the processes regulating supply and consumption of dissolved oxygen below the pycnocline. The first deployment of such a device in this area, it provided extremely high-resolution observations, 316 profiles (every 16 min, vertical resolution of 1 m) of conductivity, temperature, and depth (CTD), dissolved oxygen concentrations, backscatter, and fluorescence during a 3-day deployment. The high temporal resolution observations revealed occasional small-scale events (< 200 m or 6 h) that supply oxygenated water to the bottom layer at a rate of 2 ± 1 µmol dm−3 day−1. Benthic and pelagic oxygen sinks, quantified through glider observations and past studies, indicate more gradual background consumption rates of 2.5 ± 1 µmol dm−3 day−1. This budget revealed that the balance of oxygen supply and demand is in agreement with previous studies of the North Sea. However, the glider data show a net oxygen consumption rate of 2.8 ± 0.3 µmol dm−3 day−1, indicating a localized or short-lived (< 200 m or 6 h) increase in oxygen consumption rates. This high rate of oxygen consumption is indicative of an unidentified oxygen sink. We propose that this elevated oxygen consumption is linked to localized depocentres and rapid remineralization of resuspended organic matter. The glider proved to be an excellent tool for monitoring shelf sea processes despite challenges to glider flight posed by high tidal velocities, shallow bathymetry, and very strong density gradients. The direct observation of these processes allows more up to date rates to be used in the development of ecosystem models

Blood-Based Biomarkers in the Diagnosis of Chronic Traumatic Encephalopathy: Research to Date and Future Directions

Chronic Traumatic Encephalopathy (CTE) is a neurodegenerative disease consistently associated with repetitive traumatic brain injuries (TBIs), which makes multiple professions, such as contact sports athletes and the military, especially susceptible to its onset. There are currently no approved biomarkers to diagnose CTE, thus it can only be confirmed through a post-mortem brain autopsy. Several imaging and cerebrospinal fluid biomarkers have shown promise in the diagnosis. However, blood-based biomarkers can be more easily obtained and quantified, increasing their clinical feasibility and potential for prophylactic use. This article aimed to comprehensively review the studies into potential blood-based biomarkers of CTE, discussing common themes and limitations, as well as suggesting future research directions. While the interest in blood-based biomarkers of CTE has recently increased, the research is still in its early stages. The main issue for many proposed biomarkers is their lack of selectivity for CTE. However, several molecules, such as different phosphorylated tau isoforms, were able to discern CTE from different neurodegenerative diseases. Further, the results from studies on exosomal biomarkers suggest that exosomes are a promising source of biomarkers, reflective of the internal environment of the brain. Nonetheless, more longitudinal studies combining imaging, neurobehavioral, and biochemical approaches are warranted to establish robust biomarkers for CTE

A pilot investigation of load-carrying on the head and bone mineral density in premenopausal, black African women

Although the influence of weight bearing activity on bone mass has been widely investigated in white women, few studies have been conducted in black, African populations. We investigated bone mineral density (BMD) in black South African women, with and without a history of load-carrying on the head. We also investigated whether load carrying may offer protection against low BMD in users of injectable progestin contraception (IPC). Participants were 32 black, South African women (22.4±3.2 yrs). Load carrying history was determined by questionnaire and interview and participants were grouped as load carriers (LC; n=18) or non load carriers (NLC; n=14). Ten women were using IPC and 6 were load-carriers. Total body (TB), lumbar spine (LS) and total hip (H) BMD were measured by dual energy X-ray absorptiometry. There were no differences in BMD between LC and NLC, and after controlling for age and BMI using two-tailed partial correlations. IPC users had lower BMD at all sites compared to non IPC users (p&lt;0.05) and there were no associations between load carrying and BMD in this group. When IPC users were excluded from analysis, LC had higher LS BMD than NLC (p&lt;0.005). Correlations were found between the weight of load carried and LS BMD (r=0.743, p&lt;0.005), and between years of load carrying and LS and TB BMD (r=0.563, r=0.538 respectively; both p&lt;0.05). Load carrying on the head may offer osteogenic benefits to the spine but these benefits did not appear in women using IPC

A career in sport does not eliminate risk of cardiovascular disease; A systematic review and meta-analysis of the cardiovascular health of field-based athletes

Objectives: To determine the prevalence of cardiovascular disease (CVD) risk factors in current field-based athletes. Design: Meta-analysis. Methods: This review was conducted and reported in accordance with PRISMA and pre-registered with PROSPERO. Articles were retrieved via online database search engines, with no date or language restriction. Studies investigating current field-based athletes (>18years) for CVD risk factors according to the European Society of Cardiology and American Heart Association were screened. Full texts were screened using Covidence and Cochrane criteria. Eligible articles were critically appraised using the AXIS tool. Individual study estimates were assessed by random-effect meta-analyses to examine the overall effect. Results: This study was ascribed a 1b evidence level, according to the Oxford Centre for Evidence-based Medicine. 41 studies were identified, including 5,546 athletes from four sports; American football; soccer; rugby and baseball (mean ages:18-28). Despite participation in sport, increased body mass was associated with increased total cholesterol, low-density lipoprotein, triglycerides, hypertension, systolic blood pressure, and decreased high-density lipoprotein. Linemen had increased prevalence of hypertension compared to non-athletes. Conflicting findings on fasting glucose were prevalent. There were inconsistencies in screening and reporting of CVD risk factors. Sport specific anthropometric demands were associated with elevated prevalence of CVD risk factors, most notably: elevated body mass; dyslipidemia; elevated systolic blood pressure and; glucose Conclusions: There are elevated levels of risk for CVD in some athletes, primarily football players. Lifestyle behaviours associated with elite athleticism, particularly football linemen potentially expose players to greater metabolic and CVD risk, which is not completely offset by sport participation

Three-compartment body composition changes in elite rugby league players during a super league season, measured by dual-energy X-ray absorptiometry.

This study investigated the acute changes in body composition that occur over the course of a competitive season in elite rugby league players. Twenty elite senior players from an English Super League rugby league team underwent a total-body dual-energy X-ray absorptiometry scan at 3 phases of a competitive season: preseason (February), midseason (June), and postseason (September). Body mass (BM), fat mass (FM), lean mass, percentage body fat, and bone mineral content (BMC) were reported at each phase. Between the start and midpoint of the season, BM, lean mass, FM, and body fat percentage showed no significant change (p > 0.05); however, BMC was significantly increased (+0.71%; 30.70 ± 38.00 g; p 0.05); however, significant changes were observed in lean mass (-1.54%; 1.19 ± 1.43 kg), FM (+4.09%; 0.57 ± 1.10 kg), and body fat percentage (+4.98%; 0.78 ± 1.09%; p < 0.05). The significant changes in body composition seen over the latter stages of the competitive season may have implications for performance capabilities at this important stage of competition. An increase in FM and decrease in lean mass may have a negative effect on the power/BM ratio, and therefore may be a cause for concern for playing, coaching, and medical staff. Coaching and strength and conditioning staff should aim to prescribe appropriate training and nutritional practices with the aim of maintaining the players' optimal body composition until the conclusion of the competitive season, in order that performance capabilities are maximized over the entire competition period

A new approach to the classification of muscle health: preliminary investigations

Objective: Upper leg skeletal or lean tissue mass (LTM), strength and muscle quality have emerged as time-sensitive indices of muscular health. The aim of this study was to generate a comparative data set based on these indices, in healthy young (n  =  30, 29.0  ±  3.0 y old) and older (n  =  32, 58.7  ±  2.8 years old) adults, in order to evaluate their construct validity in establishing cut-points for muscle health. Approach: Whole body and upper leg LTM was obtained (iDXATM; GE Healthcare, Madison, WI) prior to the assessment of maximal voluntary isometric torque of the knee extensors and flexors (Cybex Isokinetic Dynamometer; Humac Norm, USA). Main results: Peak isometric upper leg torque showed the greatest age-related difference (−29.0%), followed by muscle quality (−19.1%) and upper leg LTM (–9.8%). Significance: Cut-points based on Z and T-scores generated from the young adult mean suggest muscle quality demonstrates the greatest construct validity toward the aim of classifying the muscular health of adults. Data generated from large, representative and sex-specific samples are required to adequately classify the muscular health of adults

Precision of the Integrated Cognitive Assessment for the assessment of neurocognitive performance in athletes at risk of concussion

Choice reaction time tests are commonly used for the assessment of cognitive function, and may be useful to assess the effect of mild traumatic injuries or concussions. This study investigated the precision of the Integrated Cognitive Assessment (ICA; Cognetivity Neurosciences Ltd., Vancouver, Canada) test for the assessment of cognitive function in athletes. Thirty-one participants volunteered to take part in this study, from both contact (n = 22) and non-contact sports (n = 9). Participants performed the ICA test consecutively both before and after normal training session to simulate resting and post-sport conditions. Precision errors were calculated for three variables, ICA Index (overall information processing ability), ICA Speed (information processing speed) and ICA Accuracy (information processing accuracy). ICA precision errors [root mean squared-standard deviation, RMS-SD (coefficient of variation, %CV)] pre-sport were ICA Index: 5.18 (7.14%), ICA Speed: 3.98 (4.64%), and ICA Accuracy: 3.64 (5.00%); and post-sport were ICA Index: 3.96 (4.94%), ICA Speed: 2.14 (2.32%), and ICA Accuracy 3.40 (4.25%). The ICA test demonstrates high in-vivo precision with all variables, with all variables except ICA Index (7.14%) demonstrating an acceptable precision error of ≤5% %CV. The ICA test is suitable for the assessment of cognitive function pre- and post-sport

ECG findings in professional rugby players using international screening recommendations.

BackgroundWhile World Rugby guidelines do not mandate the inclusion of an electrocardiogram (ECG) for all players, this is required for entry into international rugby competitions. We, therefore, sought to describe sport-specific normative ECG values and evaluate the performance of contemporary athlete ECG guidelines in male and female professional rugby players.MethodsWe retrospectively analysed professional rugby players' ECGs (n=356, male 79%) obtained during preparticipation screening (2010-2022), comparing by sex and playing position (forwards vs backs). ECGs were categorised as normal 'training-related', borderline and abnormal findings, as defined by the 2017 International Recommendations.Results84% of players had one or more normal, 'training-related' findings, with males having a higher prevalence than females (91% vs 60%, pConclusionsThe application of contemporary ECG interpretation criteria resulted in a low positivity rate isolated to male players. These results help inform the logistic feasibility of ECG-inclusive screening, which is already required to enter major tournaments

Cardiovascular risk and systemic inflammation in male professional rugby: a cross-sectional study

Objective: To investigate cardiovascular risk factors’ prevalence and association with systemic inflammation in professional male rugby players (RP). Methods: A cross-sectional investigation of 46 professional male RP (26.1±4.1 years) cardiovascular risk factors were compared by position. Inflammatory markers were compared with healthy controls (n=13) and patients with rheumatoid arthritis (RA) (n=10). Results: Twenty-six per cent of RP had no risk factors, 49% had 1–2 cardiovascular risk factors and 25% had 3–4 risk factors. Forwards had greater body fat (p<0.001), visceral fat (p<0.001), glucose (p=0.025), and C reactive protein (CRP) (p=0.023) compared with backs. RP demonstrated more favourable lipid and glucose profiles than reference values for the general population. Most RP (n=28, 61%) had elevated blood pressure (≥140/90 mm Hg). RP had higher vascular adhesion molecule-1 (VCAM-1) (p=0.004) and intracellular adhesion molecule-1 (ICAM-1) (p=0.002) than healthy controls. RP had lower CRP than patients with RA (p=0.009), while one-third (n=15) displayed equivalent ICAM-1 and VCAM-1 levels. Multivariate clustering and principal component analysis biplots revealed higher triglycerides, inflammatory markers, and worse body composition were associated with forwards. Conclusions: Despite athletic status, most of this rugby cohort had at least one cardiovascular risk factor. Concomitantly, these RP demonstrated increased levels of inflammation, with one-third, primarily forwards, displaying equivalent levels to patients with inflammatory disease. Further studies are needed to unravel the prognostic implications of increased inflammation in RP because unchecked, chronic inflammation may lead to increased cardiovascular disease risk