Giuseppe Rabita

• Ph.D.
• Researcher at French Institute of Sport (INSEP)

The objective of this study was to characterize the mechanics of maximal running sprint acceleration in high-level athletes. Four elite (100-m best time 9.95–10.29 s) and five sub-elite (10.40–10.60 s) sprinters performed seven sprints in overground conditions. A single virtual 40-m sprint was reconstructed and kinetics parameters were calculated f...

The insufficient temporal resolution of imaging devices has made the analysis of very fast movements, such as those required to measure active muscle-tendon unit stiffness, difficult. Thus, the relative contributions of tendon, aponeurosis, and fascicle to muscle-tendon unit compliance remain to be determined. The present study analyzed the dynamic...

Inter-individual variability of performance in fast movements is commonly explained by a difference in maximal muscle-shortening velocity, due to differences in the proportion of fast-twitch fibers. To provide a better understanding of the capacity to generate fast motion, this study aimed i) to measure, for the first time in vivo, the maximal fasc...

This study aimed to validate a simple field method for determining force- and power-velocity relationships and mechanical effectiveness of force application during sprint running. The proposed method, based on an inverse dynamic approach applied to the body center of mass, estimates the step-averaged ground reaction forces in runner's sagittal plan...

Performance during human movements is highly related to force and velocity muscle capacities. Those capacities are highly developed in elite athletes practicing power-oriented sports. However, it is still unclear whether the balance between their force and velocity-generating capacities constitutes an optimal profile. In this study, we aimed to det...

Purpose: The application of horizontal resistance is key in sprint training to modulate velocity and promote adaptations. However, the interaction between velocity and resistance on muscle excitation remains insufficiently studied. This study assessed the electromyographic (EMG) activity of thigh and gluteal muscles in response to varying velocity...

To assess how altitude training impacts force-velocity-power (F-V-P) profiling and muscular power and anaerobic capacity in elite badminton players in reference to intra- and inter-individual sex-based variability. Following a quasi-experimental design, 14 players (6 females, 8 males) from the French national badminton singles and doubles teams per...

INTRODUCTION: This study aimed to assess how altitude training impacts force-velocity-power (F-V-P) profiling and Win- gate test in elite badminton players in reference to intra- and inter-individual gender-based variability. METHODS: Fourteen players (6 females, 8 males) from the French national badminton doubles team performed a 3-week “living hi...

Background Various training programs aim to make athletes faster by using methods like sprinting with additional resistance. Given that sprint running is associated with a high risk of hamstring injuries, it is of major importance for injury prevention to assess the effect of such training on lower limb electromyographic (EMG) activity. Objective...

Background Hamstring strain injuries (HSI) are prevalent in elite sports. Monitoring for (re-)injury prevention often includes tests such as the straight-leg-raise, reflecting the stiffness of all the tissues crossing the hip joint. Alternatively, ultrasound shear wave elastography (SWE) allows to assess the regional shear modulus (index of elastic...

Muscle volume is a useful quantitative biomarker in sports, but also for the follow-up of degenerative musculo-skelletal diseases. In addition to volume, other shape biomarkers can be extracted by segmenting the muscles of interest from medical images. Manual segmentation is still today the gold standard for such measurements despite being very tim...

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While the Player Load is a widely-used parameter for physical demand quantification using wearable accelerometers, its calculation is subjected to potential errors related to rotational changes of the reference frame. The aims of this study were (i) to assess the concurrent validity of accelerometry-based Player Load against force plates; (ii) to v...

Interactions between human movement and surfaces have previously been studied to understand the influence of surface properties on the mechanics and energetics of jumping. However, little is known about the muscle-tendon unit (MTU) mechanics associated with muscle activity and leg adjustments induced by different surfaces during this movement. This...

The aim of this study was to examine the concurrent validity of the Kinexon local positioning system (LPS) in comparison with the Vicon motion capture system used as the reference. Five recreationally active men performed ten repetitions of linear sprints, medio-lateral side-to-side and handball-specific movements both in the centre and on the side...

Purpose Muscle–tendon units are forcefully stretched during rapid deceleration events such as landing. Consequently, tendons act as shock absorbers by buffering the negative work produced by muscle fascicles likely to prevent muscle damage. Landing surface properties can also modulate the amount of energy dissipated by the body, potentially effecti...

Animal tendons have been shown to act as shock absorbers to protect muscle fascicles from exercise‐induced damage during landing tasks. Meanwhile, the contribution of tendinous tissues to damping activities such as landing has been less explored in humans. The aim of this study was to analyze in vivo fascicle‐tendon interactions during drop landing...

The application of a series of extremely high accelerative motor-driven quick releases while muscles contract isometrically (i.e. slack test) has been proposed to assess unloaded velocity in human muscle. This study aimed to measure gastrocnemius medialis fascicle (VF) and tendinous tissues shortening velocity during motor-driven quick releases per...

Purpose: This study aimed to evaluate the effect of multiple sets of repeated-sprint ability (RSA) induced fatigue on subsequent passing skill performance among field hockey. Methods: Ten elite U-21 male field hockey players performed five sets of a combination of RSA test (6 × 20 m - 20 s of passive recovery) followed by a 1-min passing skill t...

We investigated the effects of the initial length of the muscle-tendon unit (MTU) and muscle pre-activation on muscle-tendon interactions during plantarflexion performed at maximal velocity. Ultrasound images of gastrocnemius medialis were obtained on 11 participants in three conditions: 1) active plantarflexion performed at maximal velocity from t...

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Purpose: Muscle fascicles-tendon interactions are the main determinant in production of high joint velocity. Currently, no study has investigated the muscle fascicles behaviour of knee extensor muscles until the highest reachable velocity (e.g., unloaded knee extension). We aimed to track the changes in vastus lateralis fascicles length during kne...

This study aimed to compare the force (F)-velocity (v)-power (P)-time (t) relationships of female and male world-class sprinters. A total of 100 distance-time curves (50 women and 50 men) were computed from international 100-m finals, to determine the acceleration and deceleration phases of each race: (a) mechanical variables describing the velocit...

This study aimed to compare the force (F) - velocity (v) - power (P) - time (t) relationships of female and male world-class sprinters. A total of one hundred distance-time curves (50 women and 50 men), were computed from international 100-m finals, to determine the acceleration and deceleration phases of each race: 1) mechanical variables describi...

Résumé Le muscle est le plus souvent étudié au travers de variables comme la force, la puissance, l’endurance. Moins d’attention a été apportée à l’exploration et à la mesure des propriétés passives du système musculo-articulaire (SMA). Les outils et systèmes dynamométriques conçus à cet effet sont configurés de façon : à mobiliser passivement l’ar...

Traditionally, muscle is studied through parameters as strength, power and endurance characteristics of muscle. Much less attention has been given to investigate and evaluate the passive mechanical properties of the Musculoarticular System (MAS). Tools and dynamometric systems have been designed in order to i) mobilise passively the joint at low sp...

The characterization of the mechanical properties of the series elastic elements (SEE) is fundamental to a better understanding of its role in the whole muscle-tendon unit and the mechanisms responsible for muscle adaptation to modified functional demand (pathology or training). According to the Hill’s muscle model, the SEE represents the nonlinear...

This study determined the concurrent validity and reliability of force, velocity and power measurements provided by accelerometry, linear position transducer and Samozino’s methods, during loaded squat jumps. Seventeen subjects performed squat jumps on two separate occasions in 7 loading conditions (0% to 60% of the maximal concentric load). Force,...

Videos of the conference are now available online! http://www.canal-insep.fr/enhancing-muscle-capacities-strength-power-velocity INSEP, the French National Institute of Sport, is proud to announce the organization of an international conference entitled "Enhancing muscle capacities: strength, power, velocity", to take place in Paris on 19-20 May 2...

This study aimed to investigate the coordination of lower limb muscles during a specific fencing gesture in relation to its mechanical effectiveness. Maximal isokinetic concentric and isometric plantarflexor, dorsiflexor, knee and hip extensor and flexor torques of 10 female elite saber fencers were assessed and compared between both legs. Sabers c...

Traditionally, isokinetic dynamometers have been used to measure variables associated with strength, power and endurance characteristics of muscle. Much less attention has been given to their potential for measuring the passive mechanical properties of the musculoarticular system (MAS). These dynamometers are configured in order to i) mobilise pass...

Background: The role of arm motion during the long jump has been well studied. The aim of this study was to quantify the effect of forearm mass on impulse and the kinematics of the flight phase in an upper limb amputee. Case description and methods: A world-record paralympic long jumper carried out jumps in three conditions: wearing his usual fo...

The aim of this study was to evaluate concomitantly the changes in leg-spring behavior and the associated modifications in the lower limb muscular activity during a constant pace run to exhaustion at severe intensity. Methods: Twelve trained runners performed a running test at the velocity associated with VO2max (5.1 ±0.3 m.s-1; mean time to exhaus...

We investigated the changes in step temporal parameters and spring-mass behaviour during the running phase of a major international triathlon competition. 73 elite triathletes were followed during the 2011 World Championships Grand Final. The running speed, ground contact and flight times were assessed over a 30 m flat section at the beginning of t...

The aim of this study was to propose and validate a simple field method to determine individual force, velocity and power output properties of sprint running. On the basis of 5 split times, this method models the horizontal force an athlete develops over sprint acceleration using a macroscopic inverse dynamic approach. Low differences in comparison...

We read with attention the recent narrative literature review by Pearson and McMahon [1]. We were very surprised and quite disappointed by the amount of relevant literature omitted by the authors on lower limb mechanical properties and, specifically, how ‘limb stiffness’ could affect performance and risk of injury. Although this review focuses on m...

The objective of this study was to examine the contribution of intrinsic ankle stiffness to leg-spring stiffness in high level athletes using various musculotendinous solicitations. 8 aerobic gymnasts (G), 10 long-distance runners (R) and 7 controls (C) were evaluated using quick-release and sinusoidal perturbation tests in order to quantify their...

The aims of this study were i) to evaluate changes in leg-spring behavior during an exhaustive run in elite triathletes and ii) to determine whether these modifications were related to an increase in the energy cost of running (Cr). Nine elite triathletes ran to exhaustion on an indoor track at a constant velocity corresponding to 95% of the veloci...

This study investigated neuromuscular fatigue following high versus low-intensity eccentric exercise corresponding to the same amount of work. Ten volunteers performed two eccentric exercises of the elbow flexors: a high-intensity versus a low-intensity exercise. Maximal voluntary contraction torque and surface electromyography of the biceps brachi...

The aim of this study was to characterize the influence of intrinsic musculotendinous and musculoarticular stiffness of plantarflexor muscles on (1) the overall musculoskeletal stiffness and (2) the performance during stretch-shortening cycles-type exercise. The influence of plyometric training background on these relationships was also analyzed. M...

PurposeThe effects of vitamins and minerals complex supplementation on maximal voluntary contraction decrease (FMV) and biological markers following an eccentric exercise at old people.

This double-blind study investigated the effects of vitamin and mineral complex supplementation on the neuromuscular function of the knee-extensor muscles after a prolonged trail running race. Twenty-two well-trained endurance runners took either placebo (Pl group) or vitamins and minerals (Vm group) for 21 d before the race and for 2 d after the r...

Although numerous studies revealed that isokinetic dynamometers were valuable tools for assessing spastic hypertonia, no standard methodology using such devices is currently widespread in clinical setting. The aim of this study was to standardize a protocol to assess spastic hypertonia in the triceps surae. The passive resistance during dorsiflexio...

The purpose of this study was first to compare the kinematic parameters of imposed ankle mobilizations measured during Ashworth or isokinetic tests and, second, to better understand why the stretch reflex was more or less easily elicited by one method or the other. Passive dorsiflexions were applied on eight adult patients with plantarflexor spasti...

This study determined the effects of a short period of knee isometric training on the quadriceps muscles accessible to surface electromyography (EMG). For this purpose, a training (n = 9) and a control (n = 7) group were tested on five identical occasions at 1 week intervals during 4 weeks. The training group exercised three times a week by making...

The purpose of the study was to test the ability to determine the velocity associated with peak oxygen uptake for adolescents by means of a simple field test, the Université de Montréal Track Test (UMTT). Fifteen adolescents, 13.4 +/- 1.0 years, performed two maximal field tests where oxygen uptake and heart rate were continuously monitored. The fi...