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Sprint performance can be characterized through the centre of mass (COM) velocity over time. In-field computation of the COM is key in sprint training.To compare the stance-averaged COM velocity computation from a Magneto-Inertial Measurement Units (MIMU) to a reference system: force platforms (FP), over the early acceleration phase in both straight and curve sprinting.Nineteen experienced-to-elite track sprinters performed 1 maximal sprint on both the straight and the curve (radius = 41.58 m) in a randomized order. Utilizing a MIMU-based system (Xsens MVN Link) and compared to FP (Kistler), COM velocity was computed with both systems. Averaged stance-by-stance COM velocity over straight-line and curve sprinting following the vertical axis (respectively V148 stances were analyzed. V

International audience; This study aimed to measure the contribution of each body segment to the production of total body kinetic energy (KE) during a 40-m sprint. Nine recreational sprinters performed two 40-m sprints wearing a MVN Biomech suit (Xsens). Data recorded were used to calculate total body KE, and the KE of each segment. The KE of each segment was then expressed as a percentage of the total body KE. We divided the sprint into three phases: 1 – start to maximal power (Pmax), 2 – Pmax to maximal velocity (Vmax), and 3 – Vmax to the end of the 40 m. Total body KE increased from the start to the end of the 40-m sprint (from 331.3 ± 68.4 J in phase 1 to 2378.8 ± 233.0 J in phase 3; p ≤ 0.001). The contribution of the head–trunk increased (from 39.5 ± 2.4% to 46.3 ± 1.1%; p ≤ 0.05). Contribution of the upper and lower limbs decreased over the three phases (respectively from 15.7 ± 2.5% to 10.6 ± 0.6% and from 44.8 ± 2.1% to 43.1 ± 1.5%; p ≤ 0.05). This study revealed the important contribution of the trunk to forward propulsion throughout the entire acceleration phase.

Objective:The aim of the study was to identify the impact of prenatal lectures in breastfeeding and neonatal care in Romania. Methods:We distributed a questionnaire to mothers who gave birth at the Bucur Maternity, Bucharest, Romania. A study group was constituted from women who attended prenatal lectures and their answers were compared with those from women who did not have prenatal education. Results:The study included 122 women. Primiparous women tend to participate in educational lectures to a greater extent than others (p=0.001). Participants in prenatal lectures breastfeed longer than non-participants (.0.001) and they had at least university studies in a higher proportion (94.06%) than non-attenders (52.38%). Women without prenatal lectures live predominantly in rural areas (p=0.003). Most women who attended classes (86.2%) considered that information provided by prenatal lectures was useful. Exclusively breastfeeding was more frequent among participants (47.49%) than non-participants (38.89%). Conclusion:Primiparity, high level of education and living in urban areas are the main characteristics of female participants in prenatal lectures, who tend to breastfeed longer and ensure exclusive human milk feeding for their babies in a higher proportion than non-participants.

Part 3: Cryptography; International audience; The dawning era of quantum computing has initiated various initiatives for the standardization of post-quantum cryptosystems with the goal of (eventually) replacing RSA and ECC. NTRU Prime is a variant of the classical NTRU cryptosystem that comes with a couple of tweaks to minimize the attack surface; most notably, it avoids rings with “worrisome” structure. This paper presents, to our knowledge, the first assembler-optimized implementation of Streamlined NTRU Prime for an 8-bit AVR microcontroller and shows that high-security lattice-based cryptography is feasible for small IoT devices. An encapsulation operation using parameters for 128-bit post-quantum security requires 8.2 million clock cycles when executed on an 8-bit ATmega1284 microcontroller. The decapsulation is approximately twice as costly and has an execution time of 15.6 million cycles. We achieved this performance through (i) new low-level software optimization techniques to accelerate Karatsuba-based polynomial multiplication on the 8-bit AVR platform and (ii) an efficient implementation of the coefficient modular reduction written in assembly language. The execution time of encapsulation and decapsulation is independent of secret data, which makes our software resistant against timing attacks. Finally, we assess the performance one could theoretically gain by using a so-called product-form polynomial as part of the secret key and discuss potential security implications.

The maximal total power (Pmax) is one of the major determinants of sprint performance. It can be calculated using a simple model based on the runner’s velocity. This velocity has already been measured with force plates, video cameras or a radar system, but not with an inertial system. The purpose of this study was to compare Pmax measured with a radar system and with a multiple inertial sensors system. Seven participants (174.0 ± 6.9 cm; 67.7 ± 10.1 kg; 22.3 ± 1.7 years) realized two maximal 40-m sprints. Each athlete was equipped with an instrumented suit composed of 17 inertial measurement units (IMU) (Xsens), and a radar (Stalker ATS) was placed behind them. Both systems measured the athletes’ instantaneous horizontal velocity during the acceleration phase. Using an exponential model, Pmax, maximal velocity (Vmax), the slope of the exponential model (τ), maximal force (F0) and the slope of the force, the velocity relationship (SFV) was calculated. The results showed that Pmax, Vmax, τ, F0 and SFV were not significantly different between the radar and the Xsens system (p > 0.13). Pmax, Vmax and F0 measured with the radar were correlated with the same parameters measured with Xsens (r > 0.81 and p ≤ 0.03). The IMU system can be accurately used to measure the main parameters that determine the sprint running performance: Pmax, Vmax and F0. Moreover, contrary to the radar system, multiple inertial sensors will allow for an understanding of the role of the segments in maximal sprint running.

In boxing, an efficient punch requires a combination of force, velocity and stability of the athlete. Being able to monitor these parameters has the potential to better inform training practices required to reach high performance. Hence, the aim of this study was to investigate the differences in punching execution between two groups of elite boxers (senior vs. junior) using three biomechanical indicators of performance in boxing. Each athlete was equipped with an instrumented suit composed of 17 inertial measurement units (IMU) and were asked to perform several series of punches with 3 standardized punching techniques (cross, hook and uppercut) on a punching bag with maximal force. Linear velocity, stability and punch forces were computed from the different sensors. Our findings show that senior boxers systematically produced more force and at a higher velocity for the three punching techniques compared to juniors. The IMU analysis also reveals differences of joint contributions between seniors and juniors, juniors presenting a higher contribution of the shoulder for the three punching techniques.

In this paper, we introduce a framework for the benchmarking of lightweight block ciphers on a multitude of embedded platforms. Our framework is able to evaluate the execution time, RAM footprint, as well as binary code size, and allows one to define a custom “figure of merit” according to which all evaluated candidates can be ranked. We used the framework to benchmark implementations of 19 lightweight ciphers, namely AES, Chaskey, Fantomas, HIGHT, LBlock, LEA, LED, Piccolo, PRESENT, PRIDE, PRINCE, RC5, RECTANGLE, RoadRunneR, Robin, Simon, SPARX, Speck, and TWINE, on three microcontroller platforms: 8-bit AVR, 16-bit MSP430, and 32-bit ARM. Our results bring some new insights into the question of how well these lightweight ciphers are suited to secure the Internet of things. The benchmarking framework provides cipher designers with an easy-to-use tool to compare new algorithms with the state of the art and allows standardization organizations to conduct a fair and consistent evaluation of a large number of candidates.

Background: Performance in discus throw requires high forces and torques generated from the shoulder of the throwing arm, making shoulder muscles at risk of overuse injury. Little is known on muscle activation patterns in elite discus throw. Hypothesis/Purpose: The purpose of this study was to examine the kinetics and shoulder muscle activation during discus throws by using two discs of different mass. It was hypothesized that the use of a lighter discus would modify the activation of the shoulder musculature compared to a standard discus.\ud Study design: Case-control laboratory study Methods: Seven male elite discus throwers performed five throws using a standard discus (STD, 2.0 kg) and five throws using a lighter weight discus (LGT, 1.7 kg). Surface EMG was recorded for the biceps brachii (BB), deltoideus anterior (DA), deltoideus medialis (DM), clavicular head of the pectoralis major (PM), latissimus dorsi (LD), and trapezius medialis (TM). Three-dimensional high-speed video analysis was utilised to record discus speed and identify the different temporal phases of each throw from the preparation phase (P1) to the delivery phase (P5).\ud Results: The EMG activation of LD lasted longer (p < 0.01) in P1 and was initiated later in P5 with the LGT discus compared to STD. In P5, the EMG intensity of BB decreased (p = 0.02) with LGT (%EMGmax = 50.4 ± 49.6%) compared to STD (64.8 ± 77.9%) and the activation of PM increased (p < 0.01) with LGT (86.2 ± 40.3%) compared to STD (66.2 ± 26.9%). The discus speed at release was increased (p = 0.04) by using the LGT discus (20.62 ± 0.75m.s-1) compared to STD (19.61 ± 0.57m.s-1). The throwing distance was also increased (P < 0.01) with the LGT (43.1 ± 4.3m) discus compared to STD (39.4 ± 3.4m).\ud Conclusion: A lighter discus could be used by elite athletes in training t 50 o add variability in muscle solicitation and thus limit the overload on certain muscles of the shoulder region. These results may have implications to lower the risk of injury in discus throw. Clinical relevance: The increase in shoulder muscle activity combined with the accelerated forward swing of the throwing arm in P5 may help explain the incidence of muscle and tendon injuries clinically observed in discus throw. Using a lighter discus in training may add variability in muscle activity and motion kinetics to lower the mechanical load on the shoulder and tendons.

SHA-512 is a member of the SHA-2 family of cryptographic hash algorithms that is based on a Davies-Mayer compression function operating on eight 64-bit words to produce a 512-bit digest. It provides strong resistance to collision and preimage attacks, and is assumed to remain secure in the dawning era of quantum computers. However, the compression function of SHA-512 is challenging to implement on small 8 and 16-bit microcontrollers because of their limited register space and the fact that 64-bit rotations are generally slow on such devices. In this paper, we present the first highly-optimized Assembler implementation of SHA-512 for the ATmega family of 8-bit AVR microcontrollers. We introduce a special optimization technique for the compression function based on a duplication of the eight working variables so that they can be more efficiently loaded from RAM via the indirect addressing mode with displacement (using the ldd and std instruction). In this way, we were able to achieve high performance without unrolling the main loop of the compression function, thereby keeping the code size small. When executed on an 8-bit AVR ATmega128 microcontroller, the compression function takes slightly less than 60k clock cycles, which corresponds to a compression rate of roughly 467 cycles per byte. The binary code size of the full SHA-512 implementation providing a standard Init-Update-Final (IUF) interface amounts to approximately 3.5 kB.

Basketball play is classically accompanied with a significant loss of body water with a potential negative impact on both physical and cognitive performance 1. Very few studies have examined the impact of dehydration on biomechanical adjustments required to score in basketball, though joints angles, the position of the centre of mass and ball release parameters (i.e. height, release speed and angle) are among the best predictive factors of success in basketball shooting 2. Dehydration might alter the biomechanical requirements of successful shots and especially three-point shots (3PS) which generate 16% of points scored during a match. However, only 35% of 3PS are successful in game. Within this framework we analysed the effects of a controlled dehydration protocol on the success and technique of 3PS in elite basketball players. Changes in shooting technique were analysed through changes in body kinematics (i.e. 3D angles of the ankle, knee, hip, shoulder, elbow and wrist, and the height of the centre of mass) and ball release parameters (i.e. height, velocity and angle of the ball at release) of 3PS in a dynamic playing condition.

Intermittent systems operate embedded devices without a source of constant reliable power, relying instead on an unreliable source such as an energy harvester. They overcome the limitation of intermittent power by retaining and restoring system state as checkpoints across periods of power loss. Previous works have addressed a multitude of problems created by the intermittent paradigm, but do not consider securing intermittent systems. In this paper, we address the security concerns created through the introduction of checkpoints to an embedded device. When the non-volatile memory that holds checkpoints can be tampered, the checkpoints can be replayed or duplicated. We propose secure application continuity as a defense against these attacks. Secure application continuity provides assurance that an application continues where it left off upon power loss. In our secure continuity solution, we define a protocol that adds integrity, authenticity, and freshness to checkpoints. We develop two solutions for our secure checkpointing design. The first solution uses a hardware accelerated implementation of AES, while the second one is based on a software implementation of a lightweight cryptographic algorithm, Chaskey. We analyze the feasibility and overhead of these designs in terms of energy consumption, execution time, and code size across several application configurations. Then, we compare this overhead to a non-secure checkpointing system. We conclude that securing application continuity does not come cheap and that it increases the overhead of checkpoint restoration from 3.79 μJ to 42.96 μJ with the hardware accelerated solution and 57.02 μJ with the software based solution. To our knowledge, no one has yet considered the cost to provide security guarantees for intermittent operations. Our work provides future developers with an empirical evaluation of this cost, and with a problem statement for future research in this area.

Boolean masking is an effective side-channel countermeasure that consists in splitting each sensitive variable into two or more shares which are carefully manipulated to avoid leakage of the sensitive variable. The best known expressions for Boolean masking of bitwise operations are relatively compact, but even a small improvement of these expressions can significantly reduce the performance penalty of more complex masked operations such as modular addition on Boolean shares or of masked ciphers. In this paper, we present and evaluate new secure expressions for performing bitwise operations on Boolean shares. To this end, we describe an algorithm for efficient search of expressions that have an optimal cost in number of elementary operations. We show that bitwise AND and OR on Boolean shares can be performed using less instructions than the best known expressions. More importantly, our expressions do no require additional random values as the best known expressions do. We apply our new expressions to the masked addition/subtraction on Boolean shares based on the Kogge-Stone adder and we report an improvement of the execution time between 14% and 19%. Then, we compare the efficiency of first-order masked implementations of three lightweight block ciphers on an ARM Cortex-M3 to determine which design strategies are most suitable for efficient masking. All our masked implementations passed the t-test evaluation and thus are deemed secure against first-order side-channel attacks.

Fatigue modifies the kinematics of various sports-related movements. Basketball induces fatigue, however, the effects of fatigue on the kinematics of shooting have never been studied. This study analysed the effects of fatigue induced by repeated sprints on the kinematics of 3-point shooting (3PS) in young, elite basketball players (U18 level). 3D joint angles were calculated at the maximum and minimum heights of the centre of mass during 3PS, using inertial measurement units (Biomech system, Xsens Technologies BV, Enschede, The Netherlands). Height, velocity and the angle of the ball at the time of release were extrapolated from the wrist joint angles. All players performed four 3PS actions in dynamic conditions before and after a fatigue protocol at 70% of their maximal exercise capacity. The fatigue protocol consisted of a shuttle test with repeated 20-m sprints interspersed with sets of 5 jumps. There was no change in the kinematics of 3PS (p > 0.05), or the ball release variables (p > 0.05) following the fatigue protocol. This suggests that elite basketball players are able to cope with physical fatigue while performing coordinated movements such as 3PS.