RUNNING INJURIES: FOREFOOT VERSUS REARFOOT AND BAREFOOT VERSUS SHOD: A BIOMECHANIST’S PERSPECTIVE

In recent years, there has been a debate regarding the use of different footfall patterns to reduce injury risk and enhance performance. Humans have three footfall patterns available to them when running: rearfoot, midfoot and forefoot. These different patterns are distinguished by the portion of the foot that’s makes initial contact with the ground. Interestingly, until very recently, there has been little research to show the pros or cons of the various footfall patterns. Here we will discuss several studies that have been carried out to distinguish footfall patterns in terms of kinematics and kinetics, running economy, the effect of surface and coordination on the risk of running injury

A Comparison of Wrist and Hip Accelerometer Output at Different Walking Speeds

Physical activity has been objectively measured using hip-worn accelerometers for decades. However, wrist-worn accelerometers are currently used in large-scale studies. Differences in wrist and hip dynamics during locomotion may affect monitor output, which may impact how prediction models are built. PURPOSE: To compare ActiGraph™ wrist and hip accelerations (g’s) at varying locomotion speeds. METHODS: Participants (N = 7) wore ActiGraph™ GT3X+ accelerometers on the dominant wrist and hip (sampling rate 80Hz). They performed three 5-minute trials at self-paced (SP), slow (SL), and fast (F) over-ground walking speeds. Mean and standard deviation of the vector magnitude (VM) were calculated from two 20-s data windows per condition. Linear mixed-effects models were used to determine if the relationship was different between speed and vector VM at the hip and wrist. RESULTS: Significant differences were found between the slopes (speed vs VM) of the hip m = 0.052 (95% CI: 0.033, 0.103) compared to the wrist m = 0.195 (95% CI: 0.160, 0.230) p\u3c0.001. DISCUSSION: The results show that ActiGraph™ wrist and hip accelerations (g’s) differ at varying locomotion speeds. There is a curvilinear increase in VM at the wrist as locomotion speed increases, whereas there is a linear increase in VM at the hip as locomotion speed increases. The pattern of change of wrist VM is different and more variable between subjects compared to hip VM, which may impact measurement error and model development. Additionally, wrist VM is more responsive to changes in speed than hip VM, suggesting that a wrist worn accelerometer may be more sensitive to locomotion intensity

On the reliability of the so far performed tests for measuring the Lense-Thirring effect with the LAGEOS satellites

In this paper we will show in detail that the performed attempts aimed at the detection of the general relativistic Lense-Thirring effect in the gravitational field of the Earth with the existing LAGEOS satellites are often presented in an optimistic and misleading way which is inadequate for such an important test of fundamental physics. E.g., in the latest reported measurement of the gravitomagnetic shift with the nodes of the LAGEOS satellites and the 2nd generation GRACE-only EIGEN-GRACE02S Earth gravity model over an observational time span of 11 years a 5-10% total accuracy is claimed at 1-3sigma, respectively. We will show that, instead, it might be 15-45% (1-3sigma) if the impact of the secular variations of the even zonal harmonics is considered as well.Comment: LaTex2e, 22 pages, 1 figure, 1 table, 60 references. Conclusions and Table of Contents added. Estimates of the impact of J6dot on the node-node-perigee combination presented. Typos corrected and minor stylistic changes. Small changes due to G. Melki useful remarks. Lense-Thirring 'memory' effect in EIGEN-GRACE02S discusse

Potential health effects of dietary nitrate supplementation in aging and chronic degenerative disease

In the United States, latest projections indicate the number of adults 65 years of age and older is expected to double by 2050. Given that increased oxidative stress is a hallmark of aging, it is understandable that waning nitric oxide and chronic degenerative disease arise in tandem. To this end, translational evidence-based strategies are needed to mitigate the impending toll on personal and public health. Dietary nitrate supplementation, particularly in the form of beetroot juice, is an active area of inquiry that has gained considerable attention in recent years. Compelling evidence has revealed beetroot juice can elicit potent physiological responses that may offer associated health benefits for multiple clinical disorders including hypertension, dementia, and sarcopenia. Even in the absence of overt disease, age-related impairments in cardiovascular and skeletal muscle function may uniquely benefit from beetroot juice supplementation as evidence has shown blood pressure lowering effects and improved muscle function/contractility – presumably from increased nitric oxide bioavailability. This, in turn, presents a practical opportunity for susceptible populations to support ease of movement and exercise tolerance, both of which may promote free-living physical activity. A theoretical rationale details the potential health effects of dietary nitrate supplementation, wherein a working framework hypothesizes beetroot juice consumption prior to structured exercise training may offer synergistic benefits to aid healthy aging and independent-living among older adults

The scattering of muons in low Z materials

This paper presents the measurement of the scattering of 172 MeV/c muons in assorted materials, including liquid hydrogen, motivated by the need to understand ionisation cooling for muon acceleration. Data are compared with predictions from the Geant 4 simulation code and this simulation is used to deconvolute detector effects. The scattering distributions obtained are compared with the Moliere theory of multiple scattering and, in the case of liquid hydrogen, with ELMS. With the exception of ELMS, none of the models are found to provide a good description of the data. The results suggest that ionisation cooling will work better than would be predicted by Geant 4.7.0p01.Comment: pdfeTeX V 3.141592-1.21a-2.2, 30 pages with 22 figure

Using wearable technology data to explain recreational running injury: A prospective longitudinal feasibility study

Objectives Investigate 1) if collecting and analysing wristwatch inertial measurement unit (IMU) and global positioning system (GPS) data using a commercially-available training platform was feasible in recreational runners and 2) which variables were associated with subsequent injury. Design Prospective longitudinal cohort. Participants Healthy recreational runners. Main outcome measures We set a priori feasibility thresholds for recruitment (maximum six-months), acceptance (minimum 80%), adherence (minimum 70%), and data collection (minimum 80%). Participants completed three patient-reported outcome measures (PROMS) detailing their psychological health, sleep quality, and intrinsic motivation to run. We extracted baseline anthropometric, biomechanical, metabolic, and training load data their IMU/GPS wristwatch for analysis. Participants completed a weekly injury status surveillance questionnaire over the next 12-weeks. Feasibility outcomes were analysed descriptively and injured versus non-injured group differences with 95% confidence intervals were calculated for PROM/IMU/GPS data. Results 149 participants consented; 86 participants completed (55 men, 31 women); 21 developed an injury (0.46 injuries/1000 km). Feasibility outcomes were satisfied (recruitment = 47 days; acceptance = 133/149 [89%]; adherence = 93/133 [70%]; data collection = 86/93 [92%]). Acute load by calculated effort was associated with subsequent injury (mean difference −562.14, 95% CI -1019.42, −21.53). Conclusion Collecting and analysing wristwatch IMU/GPS data using a commercially-available training platform was feasible in recreational runners

Beetroot supplementation in women enjoying exercise together (BEE SWEET): Rationale, design and methods

Background: Postmenopausal women exhibit higher rates of disability and cardiovascular disease (CVD) with aging compared to men. Whereas habitual exercise training is a known strategy to enhance physiologic function in men and premenopausal women, exercise-related adaptations are often modest in postmenopausal women. We propose dietary nitrate (beetroot juice) administered prior to exercise training may be a feasible approach to improve mobility and cardio-metabolic health outcomes in postmenopausal women. Methods: Our randomized, placebo-controlled study aims to determine preliminary effects sizes for changes in functional mobility and endothelium-dependent vasodilation across three study arms: exercise only (EX), exercise + placebo (EX + PL), and exercise + beetroot (EX + BR). Thirty-six postmenopausal women are recruited in small cohorts wherein group exercise is implemented to facilitate social support and adherence to an 8-week training progression. Participants are randomized to one of three study arms (n = 12 per group) following baseline assessments. Post-intervention assessments are used to determine pre-post changes in outcome measures including distance covered during a 6 min walk test, walking economy, muscle speed and power, and endothelial-dependent vasodilation as determined by flow-mediated dilation. Measures of feasibility include recruitment, retention, adherence to exercise prescription, perceived exercise session difficulty, and adverse event rates. Discussion: Evidence-based, translational strategies are needed to optimize exercise training-related adaptations in postmenopausal women. Findings will inform larger randomized clinical trials to determine if pre-exercise consumption of beetroot juice is an efficacious strategy to promote mobility and attenuate CVD disease risk

Multi-directional peak tibial accelerations in over-ground, level, running : a multicenter study

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