Sport & Training

SPORT AND HORMONE SECRETION
The correlation between the specificity of the sport practiced and the hormonal profile of the athlete is well known: indeed exercise can induce a significant hormonal response, not only in terms of acute adaptation to the exercise itself, but also as long-term response to the exercise itself (Inoue and coll., 1994; Viru, 1994; Kraemer and coll., 1996). The vibration training, too, produces adaptive hormonal response with an increasing in TESTOSTERONE (C) and SOMATOTROPE HORMONE (GH) concentration together with a decrease in the concentration of CORTISOLE (C) (Bosco and coll., 2000). The VT, if adequately repeated, can induce long-term hormonal adaptations that imply another long-term adaptation of neuromuscular functions (Bosco and coll., 2000).

MUSCULAR POWER
A Physioplate training with sinusoidal vibrations at 26/28 Hz of frequency causes a very important increase in mechanical power. Runge and coll. (2000) report an increase by 18% in lower limb power in an elderly population undergoing vibration training with the following procedure: 3 sessions per week, 3 repetitions each one lasting 2 minutes at a frequency of 27 Hz, for a total duration of 12 weeks.

ISOMETRIC FORCE
After a vibration training of 12 weeks, Decluse and his collaborators (2003) have recorded a significant increasing in isometric and dynamic force of lower limbs corresponding to 16.6 and 9.0%, respectively. These results show that the vibration training brings about a correlated adaptation and a neural strengthening, similar to those induced by the traditional training of force and power.

RECRUITMENT MODE AND PROPRIOCEPTION
During the training with vibrations, the interneurons placed in the spinal cord receive input both by the afferent and descending fibers, influencing motoneurons activities. The interaction of these different inputs determines how motor units are recruited during movement. The increase in force in the first phases of training is triggered by an optimization of this mechanism of proprioceptive feedback (Gandevia, 2001).

SYNCHRONISATION UM
The vibration training can improve the explosive force capacity thanks to a high synchronization of the motor units involved in the movement, to an improvement in the coordination of synergic muscles and to an increase in the inhibition of the antagonist muscles (Bosco and coll., 2000). Importantly, the vibration training can induce positive and long-term neuromuscular adaptations.

STIMULATING FAST FIBRES (FT)
During vibrant training, the body undergoes huge acceleration stress: for example, at a frequency of 30 Hz and an oscillation amplitude of 5 mm, the body is subject to an acceleration 18 times higher than the acceleration of gravity (Rittweger and coll., 2001). On the other hand, during a classic plyometric exercise (jump with a previous downward fall), the acceleration developed is only equal to 5 G. Undergoing such strong acceleration is a very important factor to increase power.

COMPARISON OF VIBRATION TRAINING WITH OTHER TYPES OF TRAINING
Vibration training in sport is very effective: 10 minutes of vibration training with an acceleration of 17 G correspond to the same acceleration load obtained with 40 sessions of 200 drop jumps falling from an height of 100 cm (Bosco and coll., 2000).