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Keywords: Compression; vibrations; exercise; accelerometers EN Compression vibrations exercise accelerometers S439 S441 3 01/29/21 20191002 NES 191002 1. Participants had to perform 3 maximal barefoot Squat Jump (SJ) in 4 conditions: No compression (NC), with a heddle compression sleeve (HC), with a selective compression sleeve (SC), and with a selective compression sleeve with a breakthrough mesh (SCB). The authors found that the muscular oscillations decrease with compression sleeves and they are more important with a high compression (30 mmHg) than a low compression (15 mmHg). Effects of a new selective compression garment on thermoregulation and muscular oscillations during exercise. [Extracted from the article]

Numerous workers are exposed to vibrations which can turn out to be fatal for the health. Athletes can be included in this population, in particular cyclists who are exposed to vibration due to the irregularity of the road. This nuisance depends of the duration of exposure and the range of vibrations. While the worker is mostly directly excited by a vibrating system, the cyclist is indirectly subjected to it. He undergoes the vibrations of an excited sub-structure which is the bicycle. So the bicycle plays the role of a vibration filter or amplifier. In this paper we propose to (i) study the transmission of vibrations to the cyclist after excitation on a paving road, (ii) calculate the limit time of exposure to this type of excitation rate by the use of the standard ISO 5349 and the European directive 2002/44/EC, and (iii) compare the weighting curve of the standard with a vibrations transmissibility curve obtained between the collarbone and the stem. For this particular case of an excited sub-structure, a weighting curve is proposed by considering the first modal frequency of the bicycle. [ABSTRACT FROM AUTHOR]

The aim of this study was to test the validity and the reliability of the G-Cog which is a new BMX powermeter allowing for the measurements of the acceleration on X-Y-Z axis (250 Hz) at the BMX rear wheel. These measurements allow computing lateral, angular, linear acceleration, angular, linear velocity and the distance. Mechanical measurements at submaximal intensities in standardized laboratory conditions and during maximal exercises in the field conditions were performed to analyse the reliability of the G-Cog accelerometers. The performances were evaluated in comparison with an industrial accelerometer and with 2 powermeters, the SRM and PowerTap. Our results in laboratory conditions show that the G-Cog measurements have low value of variation coefficient (CV = 2.35%). These results suggest that the G-cog accelerometers measurements are reproducible. The ratio limits of agreement of the rear hub angular velocity differences between the SRM and the G-Cog were 1.010 × ÷ 1.024 (95%CI = 0.986-1.034) and between PowerTap and G-Cog were 0.993 × ÷ 1.019 (95%CI = 0.974- 1.012). In conclusion, our results suggest that the G-Cog angular velocity measurements are valid and reliable compared with SRM and PowerTap and could be used to analyse the kinematics during BMX actual conditions. [ABSTRACT FROM AUTHOR]

The aim of this study was to test the validity and reliability of the G-Cog which is a new BMX power meter allowing for the measurements of the power output (250 Hz) at the BMX rear wheel during actual cycling and laboratory conditions. Sprints in road cycling (6-8 s) from static start and incremental tests in the laboratory (100-400 W) have been performed to analyse the validity and reliability of the power output values by comparison with 2 devices: The PowerTap and the SRM which are considered as the gold standard. The most important fi nding of this study is that the G-Cog power output data were not valid and reliable during sprint and standardised laboratory tests compared with the SRM and the PowerTap devices. During the sprint and the laboratory tests the ratio limits of agreement of the power output diff erences between the SRM and G-Cog were 1.884 × ÷ 1.970 (95 %CI = 0.956- 3.711) and 12.126 × ÷ 16.281 (95 %CI = 0.745- 197.430), respectively. In conclusion, the G-Cog must be used with caution regarding the power output measurements. Nevertheless, the G-Cog could be used for the first time to analyse the determinants of the BMX performance from the pedalling profile. [ABSTRACT FROM AUTHOR]

The purpose of this study was to test the validity and reliability of a new method to estimate the projected frontal area of the body during cycling. To illustrate the use of this method in another cycling speciality (i.e. mountain bike), the NM data were coupled with a powermeter measurement to determine the projected frontal area and the coefficient of drag in actual conditions. Nine male cyclists had their frontal area determined from digital photographic images in a laboratory while seated on their bicycles in two positions: Upright Position (UP) and Traditional Aerodynamic Position (TAP). For each position, the projected frontal area for the body of the cyclist as well as the cyclist and his bicycle were measured using a new method with computer aided-design software, the method of weighing photographs and the digitizing method. The results showed that no significant difference existed between the new method and the method of weighing photographs in the measurement of the frontal area of the body of cyclists in UP (p=0.43) and TAP (p =0.14), or between the new method and the digitizing method in measurement of the frontal area for the cyclist and his bicycle in UP (p =0.12) and TAP (p=0.31). The coefficients of variation of the new method and the method of weighing photographs were 0.1 % and 1.26%, respectively. In conclusion, the new method was valid and reliable in estimating the frontal area compared with the method of weighing photographs and the digitizing method. [ABSTRACT FROM AUTHOR]

A body when moving in a fluid is to withstand drag that is proportional to the drag coefficient, the frontal surface area, and the square of the body velocity relative to the fluid velocity (VOGEL [14]). The aim of our study was to determine the relationships between the drag coefficient (CD) and the Reynolds number (Re) for a high-level swimmer. In TAÏAR et at. [12], three most propulsive butterfly positions have been defined: the end of the external sweep (beginning of the cycle), the end of the internal sweep (middle of the cycle), and the end of the thrust (end of the cycle). These three positions were reproduced using real-size mannequins articulated in real-velocity conditions. Experiments have been done in the large-scale hydraulic flume of the University of Nantes. Two types of the curves CD (Re) were obtained: for the "best swimmer" and for "other swimmers". Following the swimming of the ex-word champion Pankratov during the World Championship in Rome (1994) the mannequin representing the "best swimmer" has been positioned similarly to the ex-world champion at the beginning, in the middle and at the end of cycle. The body positions of Pankratov have been obtained using the image analysis software Schleihaul[sup JM] 4.0. In order to obtain the curves CD (Re) representing "other swimmers", the body positions of lower-level swimmers have been used at the beginning, in the middle and at the end of swimming cycle. The two types of curves show well the gap between the techniques of the "best swimmer" and "other swimmers". Our study shows the importance of the body position during the swimming cycle to minimizing the drug and to assuring better propulsion, i.e. better performance. The results show that the most effective swimmers optimise the body positions in order to reduce the frontal surface and therefore to minimize the drag. [ABSTRACT FROM AUTHOR]

The article presents a study which analyzes the fatigue effect on the pedalling biomechanics parameters during a Wingate test for different cyclist types. The study used descriptive statistic, SRM crank powermeter and two tachydynamometrics pedals, and investigated four well-trained male cyclists. Results show that two of the four athletes have a decreasing power output of 13 watts per second (W/s).

The article presents a study which evaluates the agreement between the Fortius ergometer power output (PO) measurements and the PowerTap powermeter. The study uses 35 males active cyclists as subjects who used their personal bicycle fitted with the calibrated Fortius Virtual Reality cycle trainer and a PowerTap that measures the PO. Results suggests that the Fortius ergometer significantly overestimates the PO measured by the PowerTap.

The article presents a study measures the power output (PO) and identifies the rolling coefficient (Cr) in mountain bikes on different surfaces with two different tyres, the Pyhton and the Vittoria, and inflation pressures. The study uses the protocol performed by one active cyclist using a mountain bike fitted with a PowerTap. Results show that statistical differences between the two inflation pressures and tyres evaluated.

The article presents a study which examines the tubes to receive the highest strain in an instrumented bicycle motocross (BMX) frame subjected into three different conditions. The study performs simulation of torques applied at the pedal, application of maximal isometric force to the right pedal by a male rider in standing position, and pedaling in standing position at maximal intensity for 10 seconds (s). Result shows seat tube, down tube, and right chain stay to recieve the highest strains.

The article presents a study on the sprint and vertical performances and capacities of football players from Algerian football team before the Federation internationale de football association (FIFA) World Cup in 2010. The study was conducted to eight participants from Algerian football teams, in which the optojump device was used to measure the jump test performance of the participants. The study shows no relationship between vertical jump and sprint performance of football players.

The article presents a study on the determinants of muscular performance in bicycle motocross (BMX) during half-squat (HS) and sprints on a cycle ergometer. It says that maximal muscular strength is a muscular determinant of the performance on short all-out cycling sprint. It suggests that velocity and power gains during strength and power training could be managed through the help of using inertial assessment.

The article presents a study which examines the determining factors of sprint performance of riders in an 80-meter (m) sprint bicycle motocross (BMX) race. The study assesses several variables including the maximal mechanical power output (PMAX), cadence (Cad)-torque relationship, and the power-velocity relationship. Result shows the significance of PMAX, maximal theoretical torque (T0), and Cad variables to determine sprint performance.

The article presents a study which evaluates the influence of frequency and amplitude of whole-body vibration (WBV) to heart rate (HR) and to rate of perceived exertion (RPE). The study employed 10 male subjects to perform isometric semi-squat exercise on a vibration platform with different frequency and amplitude of vibration. It concludes that WBV integrated in isometric squat increases HR and fatigue due to expanded muscle activity.

The article presents study of examining the effects of foot orthoses with medial and lateral wedges on vertical posture in the sagittal plan. Topics discussed information on postural imbalances such as terior inclination of the trunk, orthotic treatment on standing postural stability, and usage of medicapteurs fusyo pressure platform to measure oscillations of the center of pressure.

The article discusses a study conducted to evaluate the efficiency of orthoptic exercise performed using fencing masks, to improve the postural control and sporting activities. Topics include maintaining coordination between the oculomotor signals and hand movements, the performance of lunges, and gesture tracking.

The article discusses the analysis of stirrup sensors through different methods. Topics include are the location of stress on the stirrups, simulation and experimental methods adopted to determine the appropriate location for the strain gauge sensor. Information on finite element model helping to determine the use of dynamometer in the strain sensors used in stirrups is also presented.

The article focuses on a study for investigating impact of triple jump repetition on the dynamic plantar support. Topics discussed include detection of foot pathologies, biomechanical foot adaptations because of triple jump and an increase in foot pronation because of foot intrinsic muscles fatigue.

The article focuses on the development of several direct Center of Mass (CoM) modeling using various technologies such as three dimensional (3D) camera and thermal imaging camera. Topics discusses include determination of accuracy and reliability of static 3D reconstruction and 3D modeling of body segment by using Direct Linear Transformation method.

The article discusses principal component analysis between perceptions and kinematics of the upper body. Topics discussed risks factors of musculoskeletal disorders and its prevention, information on relationship between back pain and office working, and table representing mean and standard deviation of joint kinematics.

The article presents analysis on locomotion of horse simulator through inertial measurement unit (IMU) to enhance rider's training programs. Topics discussed co-relation between rider's weight and experience, and behavior of horse; calculation of mean operating frequency of the simulator using Fourier transformation; and usage of Leroy Somer potentiometer for the same.

The article presents a study aimed to compare two statics methods based on the inseam length which are frequently used in the literature including Genzling method and Hamley method allowing a postural adjustment in cycling. It concludes how optimization of the cyclist's position can increase performance and may prevent overuse injuries.

The article presents a study which aims to equate the ability of two three-dimensional (3D) accelerometers to provide reliable values of a vertical displacement. An AX3 accelerometer and an accelerometer/magnetometer-3 mini USB X8M have been fixed on the ergoselect 100P cycle ergometer pedal. It was discovered that the average stride frequency rate is around close to 1.3 hertz (Hz) in a sporting horse.

The article discusses a study which aims to measure the transmissibility of vibration (T) based on the vibration's excitation frequency measure (θ) and movement represented as the relative angle between its direction and segments (ω). It states that a dynamic hack squat exercise was conducted by 14 male volunteers over the platform using a metronome. Results show low frequencies in the amplification of the input acceleration during extension and flexion.

An abstract of the article "Effect of vibration frequency and angle knee flexion on muscular activity and transmissibility function during static whole body vibration exercise," by S. Duc and colleagues is presented.

The article analyzes the relationship that exists between the gross efficiency (GE) and the muscular skin temperature of the lower limb in cycling. It mentions that the GE is the main caused of the cycling performance which is the ratio of the power output to the metabolic power that maintains the equilibrium. It notes that the infrared thermography measurements are used to analyse the thermoregulation process and understand the dissipation of energy.

The article presents a study on the biodynamic responses of the body in various frequencies and different body positions to understand the vibration transmissibility while doing whole body vibration training (WBVT) exercises. It discusses how the study was conducted which involved 17 men who do not have contraindications to WBV. The results reportedly revealed that bending on the legs and standing on the forefoot can lower vibration transmission to the head.

The article presents a study which proposes an experimental protocol to evaluate the risks and vibration transmissions in cycling. It provides information on the protocol which assesses, qualifies and quantifies the bicycle's vibration response in a bench test based on three standards. The results reportedly revealed that the protocol is sensible enough to determine the characteristics' vibrations of two bicycles.

The article presents a study on the impact of vibration while cycling on physical fitness. It discusses how the study was conducted which involved a protocol consisting of three parts to assess the transmission of vibrations in the front of the bicycle and the application of a mechanical equivalent modelling. The results reportedly revealed that the protocol presented the bicycle's vibration response at various frequencies in the stem.

The article presents a study which analyses the performance of elite athletes or BMX riders using statistics. It evaluates the cumulative density function and distribution statistics of the elite athletes to determine the holding time and analyse pacing technique during sprint. Results show that the powermeter Gcog has the potential to characterise athletes with new tools.

The article presents a study which develops new performance indicators for quantifying sequence, coordination, and management of the dead centre of the pedalling among BMX riders. The study developed determinants of performance using data from four elite athletes who performed 40 meter sprints. Results show that the three indicators developed are significantly correlated and they provide another indication of the athletes' profile.

The article presents a study on the proposed 5 degrees of freedom (DOF) system which aims to illustrate hand-arm systems vibrations in a cyclist's hands arm and its bicycle coupling. It states that to illustrate vibration transfer, two sets of measurement were conducted such as measuring without a bicycle wherein vibrating plate were used to the cyclist's hands in half-pump and the coupling of the cyclist and the bicycle. Results show the amplification of vibrational energy at the wrist.

The article presents a study which verifies if there is a correlation between the importance of the lumbago and the importance of postural asymmetry. The study performed the statistical analysis of four major criteria, compared results with AFP85 standards, and queries on the intensity of their lumbago with the use of Visual Analog Scale (VAS). Hence, it mentions that the statistical analysis shows that for all criteria, there is a VAS effect.

The article compares the muscular activation of pedalling between when cycling on a stationary ergometer and when riding on a treadmill. The study involving male competitive cyclists is described. It was found that cycling on the Axiom ergometer involves a greater activation of the lower limb compared to riding on a treadmill, at the same power output and pedalling frequency. The relationship between factors such as acceleration, deceleration or changes in pedalling techniques and the electromyography activity of the lower limb muscles must be analyzed.

Presents a study which aimed to compare Axiom and PowerTap cycle ergometers with the speed of relative movement (SRM) reference powermeter during maximal intensity exercise. Use of an ergometer to evaluate the performance of competitive cyclists; Information on the Axiom, a stationary electromagnetically ergometer, and the PowerTap, a mobile cycling powermeter; Description of the SRM system.