ANALYSIS OF COMBINED EMG AND JOINT ANGULAR VELOCITY FOR THE EVALUATION OF ECCENTRIC/CONCENTRIC CONTRACTION IN SKIING

The purpose of this study was the introduction of a method combining the joint angular velocity and the EMG signals for a biomechanical evaluation of the eccentric/concentric contraction patterns of major muscles used in alpine skiing. The adopted approach was applied to three types of slalom courses: racing, training and recreational slaloms. The introduction of a pseudo-Muscular-Work allowed to define a Ratio between Eccentric and Concentric muscular activation states that, compared to simple on-off timing criteria, resulted to reveal more consistently the amount of eccentric muscle mechanical work

Comparison of the Aerodynamic Performance of Five Racing Bicycle Wheels by Means of CFD Calculations

Aerodynamic drag is the main source of losses in cycling so improving the bicycle aerodynamic is a fundamental key factor to increase the performance. The aim of this research is to evaluate and compare the aerodynamic performance of racing bicycle wheels by means of CFD RANS numerical models: it is based on a previous work that reported the development of the numerical model. The aim of this work is to assess the capability of CFD RANS simulations to predict the aerodynamic performance of modern racing bicycle wheels. Drag and side forces are resolved over the range of different yaw angles

A three-dimensional parametric biomechanical rider model for multibody applications

Bicycles and motorcycles are characterized by large rider-to-vehicle mass ratios, thus making estimation of the rider's inertia especially relevant. The total inertia can be derived from the body segment inertial properties (BSIP) which, in turn, can be obtained from the prediction/regression formulas available in the literature. Therefore, a parametric multibody three-dimensional rider model is devised, where the four most-used BSIP formulas (herein named Dempster, Reynolds-NASA, Zatsiorsky-DeLeva, and McConville-Young-Dumas, after their authors) are implemented. After an experimental comparison, the effects of the main posture parameters (i.e., torso inclination, knee distance, elbow distance, and rider height) are analyzed in three riding conditions (sport, touring, and scooter). It is found that the elbow distance has a minor effect on the location of the center of mass and moments of inertia, while the effect of the knee distance is on the same order magnitude as changing the BSIP data set. Torso inclination and rider height are the most relevant parameters. Tables with the coefficients necessary to populate the three-dimensional rider model with the four data sets considered are given. Typical inertial parameters of the whole rider are also given, as a reference for those not willing to implement the full multibody model

THE EFFECT OF WALKING SPEED AND SKILL LEVELS ON ELBOW FLEXION AND UPPER LIMB EMG SIGNALS IN NORDIC WALKING: A PILOT STUDY

Aims of the study were to evaluate the effect of the walking speed on the elbow’s range of motion and the EMG activity levels on eight upper limb muscles when performing level Nordic Walking in outdoor sessions. The study involved both skilled Nordic Walking instructors and unskilled beginners to highlight the effect of a correct technical execution on the elbow’s flexion angle and the EMG signals. All the subjects performed also level walking tests without poles at the same speeds of the NW tests: the EMG activation levels during walking were taken as control values of each subject to estimate the additional activation due to the poles

Tinnitus revival during COVID‑19 lockdown: how to deal with it?

To the Editor, The novel Coronavirus Disease, officially designated as COVID-19 by the WHO, is a serious issue for public health. To contain the COVID-19, the Italian Government stated on March 9th 2020 the prohibition of any movement throughout the national area unless for work/health reasons and the obligation to remain as much as possible inside one’s own home. With the start of the so-called “Phase Two” on May 4th 2020, circulation within the same region was allowed again, due to the progressive slowdown of the outbreak. Therefore, since lockdown measures were relaxed and access to the emergency room or ENT clinic became less worrying for patients, specialists of Otolaryngology Units in Bari (Italy) observed an increase in the amount of subjects complaining of the revival of intense tinnitus. We attempt in this letter to focus on patients affected by chronic subjective tinnitus, that already had a diagnosis and self-stabilized without a massive treatment. Research studies have reported tinnitus wide impact on quality of life of subjects experiencing it, involving their emotional state, concentration and sleep quality; at this regard, Tinnitus Handicap Inventory (THI) is a self-reported tool regularly used to quantify the grade of perceived handicap as slight (0–16), mild (18–36), moderate (38–56), severe (58–76) or catastrophic (78–100) on the basis of 25 questions [1]. During the past 2 weeks, we have collected data from 16 patients among our population of chronic sufferers: THI observed was moderate in 62.5% and severe in 18.75% of cases, catastrophic in 12.5% and mild in 6.25% of subjects. Interestingly, the grade of handicap resulted increased by one-level in 12 out of 16 patients (75%); in particular, THI shifted from mild to moderate in 9 patients and from moderate to severe in 3 patients. As shown in the literature, tinnitus generation, maintenance and recrudescence are still debated. A cortical reorganization secondary to sensory deprivation has been proposed as one on the most frequent cause of tinnitus [2]. The avoidance of silence and acoustic masking have been proposed as effective measures to overcome sensory deprivation and increase masking of the symptom [3]. It is reasonable to think that, during the lockdown, the absence of environmental masking sounds from everyday life may have enhanced the tinnitus perception. Furthermore, proneness to worry and incoming stress during pandemic could be included as further potential risk factors for tinnitus worsening. As proficiently reviewed in a recent work [4], some internet/smartphone-based applications provide in tinnitus patients adequate counseling and interactive information together with sound therapy. As brain networks implicated in adaptive responses to sound stimuli and to worry are shared in many cases, an early decrease of anxiety status may release neural resources crucial for tinnitus habituation/distress perception [5]. In general, interactive platforms have been widely implemented during lockdown period due to the forced lack of real personal and working relationships; since smart-working seems to be successful for future plans, the development of smart applications and mobile services in the health care field may be promising in terms of cost-effectiveness, tolerability and simplicity of use

Impact of Covid - 19 Pandemic on Orthopaedics at Northwell Health, New York.

The Novel Coronavirus (COVID-19) pandemicplaced an immense strain on healthcare systems and orthopedic surgeons across the world. To limit the spread, federal and state governments mandated the cancellation of all non-urgent surgical cases to address surging hospital admissions and manage workforce and resource reallocation. During the pandemic surge, thousands of surgical cancellations have been required. We outline our experience through the onset and advance of the surge, detail our incident response, and discuss the transition toward recovery

Time-resolved energy transfer from single chloride terminated nanocrystals to graphene

We examine the time-resolved resonance energy transfer of excitons from single n-butyl amine-bound, chloride-terminated nanocrystals to two-dimensional graphene through time-correlated single photon counting. The radiative biexponential lifetime kinetics and blinking statistics of the individual surface-modified nanocrystal elucidate the non-radiative decay channels. Blinking modification as well as a 4 times reduction in spontaneous emission were observed with the short chloride and n-butylamine ligands, probing the energy transfer pathways for the development of graphene-nanocrystal nanophotonic devices

Designing, building, measuring, and testing a constant equivalent fall height terrain park jump

Previous work has presented both a theoretical foundation for designing terrain park jumps that control landing impact and computer software to accomplish this task. US ski resorts have been reluctant to adopt this more engineered approach to jump design, in part due to questions of feasibility. The present study demonstrates this feasibility. It describes the design, construction, measurement, and experimental testing of such a jump. It improves on the previous efforts with more complete instrumentation, a larger range of jump distances, and a new method for combining jumper- and board-mounted accelerometer data to estimate equivalent fall height, a measure of impact severity. It unequivocally demonstrates the efficacy of the engineering design approach, namely that it is possible and practical to design and build free style terrain park jumps with landing surface shapes that control for landing impact as predicted by the theory

Field Load Acquisition and variable amplitude fatigue testing on maxi-scooter motorcycles

Aim of the present work was the instrumentation of a maxi scooter for the field collection of service loads acting on the scooter main components such as frame, fork, handlebar, rear frame and suspension. Service loads were collected on an instrumented Yamaha Tmax scooter equipped with 22 channels during a set of field tests that were representing a predefined road mix, covering a mileage of 270 km. Field load histories were used to develop an accelerated test procedure for the accelerated bench fatigue testing of a new model prototype whose mission was set to 50000 km. The acceleration procedure allowed a time reduction from 1600 hrs to 122 hrs bench equivalent testing. Both the benchmark scooter Tmax and a maxi-scooter prototype under development underwent the bench variable amplitude fatigue testing. The results of the fatigue tests on the prototype allowed to identify some critical bolted connections and to reduce some stress concentration features causing the appearance of small cracks that were found also after during 50000 km of driving tests