The findings of this study imply that improper energy flow during the tennis serve can decrease ball velocity, increase upper limb joint kinetics, and thus increase overuse injuries of the upper limb joints.

This study investigated the influence of an incremental exercise on bilateral asymmetry through the spatio-temporal evolution of 3D joint angular displacement, using the Normalized Symmetry Index ([Formula: see text]) and cross-correlation methods. Twelve professional cyclists performed an incremental test to exhaustion, during which motion capture was used. Results revealed a decrease in range of motion between the first and last stages for twelve of the eighteen joint rotations, with the highest impact observed for right hip flexion/extension (61.8 ± 4.7° to 58.8 ± 4.1°, p < 0.05, ES = 0.68). For both stages, significant bilateral differences greater than 10° were observed for hip and knee flexion/extension (p < 0.05, ES>0.90) and ankle and hip internal/external rotation (p < 0.05, ES>0.25). Cross-correlation displayed the lowest pattern similarities for hip abduction/adduction and the highest similarities for knee flexion/extension, ankle plantarflexion/dorsiflexion and hip internal/external rotation. The cross-correlation method showed that the right leg was mostly ahead of time with respect to the left leg, a trend that was accentuated with power output increase. Instantaneous [Formula: see text] fluctuated up to 18% throughout the pedalling cycle, with different behaviour between the power and recovery phases. This study demonstrated the workload effects on side-to-side joint angular pattern similarity.

This paper presents a novel sensor-to-segment calibration procedure for inertial sensor-based knee joint kinematics analysis during cycling. This procedure was designed to be feasible in-field, autonomously, and without any external operator or device. It combines a static standing up posture and a pedaling task. The main goal of this study was to assess the accuracy of the new sensor-to-segment calibration method (denoted as the ‘cycling’ method) by calculating errors in terms of body-segment orientations and 3D knee joint angles using inertial measurement unit (IMU)-based and optoelectronic-based motion capture. To do so, 14 participants were evaluated during pedaling motion at a workload of 100 W, which enabled comparisons of the cycling method with conventional calibration methods commonly employed in gait analysis. The accuracy of the cycling method was comparable to that of other methods concerning the knee flexion/extension angle, and did not exceed 3.8°. However, the cycling method presented the smallest errors for knee internal/external rotation (6.65 ± 1.94°) and abduction/adduction (5.92 ± 2.85°). This study demonstrated that a calibration method based on the completion of a pedaling task combined with a standing posture significantly improved the accuracy of 3D knee joint angle measurement when applied to cycling analysis.

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The present study aimed to examine the effects of Spirulina supplementation on 26 anthropometrical measurements and physical performance in elite rugby players. 27Twenty-two elite male Rugby Union players (21-36 years old) volunteered to participate in this study. They were randomly assigned to a Spirulina group (SPI: n = 11), or a placebo group 29 (PLA: n = 11) in a double-blind design. Subjects were supplemented with Spirulina platensis 30 (5.7g/d) or Placebo (iso-proteic and caloric) for seven weeks. At baseline (W 0 ) and after 7 weeks 31 of supplementation (W 7 ), the same anthropometric measurements and physical performance 32 test battery were performed. These tests included isokinetic leg strength and power, vertical 33 jump, speed, and aerobic fitness assessment. 34For anthropometric data, the fat mass (FM) percentage was significantly reduced in both groups 35 without significant difference between groups. While both groups exhibited significant 36 improvements for SJ, CMJ, 10 and 30-m sprints between W0 and W7, higher percentage 37 improvements with the SPI group did not reach significance. Neither training alone (PLA) nor 38 training associated with spirulina supplementation affected leg maximal strength and power or 39 aerobic fitness. 40 Seven weeks of spirulina supplementation in elite rugby players did not improve body 41 composition nor substantially increase physical performance. We only observed a non-42 significant small advantage in vertical jump and sprint performance in the SPI group. Based on 43 the data from this study, spirulina supplementation has modest effects in elite rugby players 44 during the competitive phase. Further studies are required to verify spirulina supplementation 45 effects among athletes of different sports, age, gender and athletic level with longer durations 46 and higher dosages. 50 Spirulina (Arthrospira) is a blue-green microalga belonging to the Cyanobacteria class with 51 prokaryotic photosynthetic characteristics [1-4]. The most well-known species of spirulina safe 52 for consumption are Spirulina maxima, Arthrospira fusiformis, and platensis, this last one being 53 the most commonly used species and largely studied in the scientific literature [4, 5]. It's known 54 for its complex chemical makeup including high protein content (50 to 70% of its dry weight), 55 all the essential amino and fatty-acids, and most of the vitamins and minerals [6-8], which 56 confers to spirulina numerous health benefits such as antioxidant, immunomodulatory, anti-57 inflammatory, anti-cancer and anti-viral activities [1, 8-10]. 58 In recent years, spirulina has been widely used by athletes for these health benefit effects and 59 most of them consume it in the belief it will improve body composition, physical performance 60 and recovery. It was speculated that Chinese and Cuban Olympic teams have consumed 61 spirulina daily for many years to improve performance [2]. Data in the literature is still rare and 62 controversial about spirulina effects on anthropometric parameters and pe...

27 pagesInternational audienceThe ascending branch of the aorta is one of the most stressed organ of the arterial system. We aim to design a biomechanical model for analysing the aorta dynamics under a shock. The model includes the aorta layers and the influence of the blood pressure. First, we undertake a modal analysis of the coupled aorta-blood system. For the analytical solving we adopt the Helmholtz decomposition. The finite element model is then validated by these original analytical solutions. The second part focuses on aorta-blood dynamics, corresponding to an acceleration/deceleration during car crash. Numerical and analytical solutions are compared

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Lunge motion is one of the fundamental attacks used in modern fencing, asking for a high level of coordination, speed and accuracy to be efficient. The aim of the current paper was the assessment of fencer’s performance and response time in lunge attacks under uncertain conditions. For this study, an innovative fencing lunge simulator was designed. The performance of 11 regional to national-level fencers performing lunges in Fixed, Moving and Uncertain conditions was assessed. The results highlighted notably that i) Accuracy and success decreased significantly in Moving and Uncertain conditions with regard to Fixed ones ii) Movement and Reaction times were also affected by the experimental conditions iii) Different fencer profiles were distinguishable among subjects. In conclusion, the hypothesis that fencers may privilege an adaptation to the attack conditions and preserve accuracy instead of privileging quickness was supported by the results. Such simulators may be further used to analyze in more detail the motor control strategies of fencers through the measure and processing of biomechanical quantities and a wider range of fencing levels. It has also a great potential to be used as training device to improve fencer’s performance to adapt his attack to controlled opponent’s motion.