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The aim of this work was to study the posturokinetic capacities and use of visual information by judoists according to their level of competition. Twenty male judoists aged between 16 and 19 took part. They were separated into two groups: those that competed at regional level and those that competed at national and international level. Static balance was measured on a force platform. No difference was seen between the two groups. However, it seems that visual information is more important to the higher level judoists. Perhaps the level of competition influences the sensory canals involved in balance.

Electrical stimulation (ES) reverses the order of recruitment of motor units (MU) observed with voluntary muscular contraction (VOL) since under ES, large MU are recruited before small MU. The superimposition of ES onto VOL (superimposed technique: application of an electrical stimulus during a voluntary muscle action) can theoretically activate more motor units than VOL performed alone, which can engender an increase of the contraction force. Two superimposed techniques can be used: (i) the twitch interpolation technique (ITT), which consists of interjecting an electrical stimulus onto the muscle nerve; and (ii) the percutaneous superimposed electrical stimulation technique (PST), where the stimulation is applied to the muscle belly. These two superimposed techniques can be used to evaluate the ability to fully activate a muscle. They can thus be employed to distinguish the central or peripheral nature of fatigue after exhausting exercise. In general, whatever the technique employed, the superimposition of ES onto volitional exercise does not recruit more MU than VOL, except with eccentric actions. Nevertheless, the neuromuscular response associated with the use of the superimposed technique (ITT and PST) depends on the parameter of the superimposed current. The sex and the training level of the subjects can also modify the physiological impact of the superimposed technique. Although the motor control differs drastically between training with ES and VOL, the integration of the superimposed technique in training programmes with healthy subjects does not reveal significant benefits compared with programmes performed only with voluntary exercises. Nevertheless, in a therapeutic context, training programmes using ES superimposition compensate volume and muscle strength deficit with more efficiency than programmes using VOL or ES separately.

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In subjects of both sexes with or without dance training, dependence on vision and proprioception for postural control was studied by destabilizing these cues on a free seesaw. Fast Fourier transform processing allowed spectral frequency analysis of the platform sways recorded by an accelerometer. Two frequency bands of the total spectral energy were used: the lower (0 - 2 Hz) and the higher (2 - 20 Hz) frequency bands. Dancers were significantly less dependent on vision but use more proprioception than untrained subjects. Professional dance training appears to shift sensorimotor dominance from vision to proprioception, and this evolution seems more marked for males than females. Female and male dancers had similar dynamic performances, but for males, the better neuromuscular coordination may be associated with biomechanical factors.