a Carmelo, amico fraterno

Roberto BonomiScienze Motorie - Tor Vergata - Roma

The sprint performance is the only sportive discipline that requires the maximal expression of all strength qualities of the neuromuscular capacity on its whole. It’s therefore easy to understand that this phenomenon, totally unusual and peculiar, requires a more elaborate articulation of training means and their more sophisticated and artificial organization, compared to the methodological strategies adopted by strength disciplines par excellence, namely weightlifting and athletics throwing events.

It becomes, therefore, essential the application of a method that does not weigh on the muscular hypertrophy, but mainly influences the Central Nervous System in order to raise the higher firing rate of neural stimuli. This is the only way to increase the “instantaneous recruitment” of more motor units.

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The improving of muscular efficiency is to be ascribed chiefly to neuromuscular factors such as:

• Recruitment ,

• Synchronization,

• Intramuscular coordination .

All these factors are connected to a finer modulation of proprioceptive afferents.

MUSCULAR EFFICIENCY

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It is, also, appropriate to remind that maximum and explosive strength workouts are caused by violent accelerations exercised against gravity force. (Bosco, 1992)

FROM THE PLATE TO THE WHOLE BODY

Physical and Mechanical Stimulation with

Whole Body Vibration

leads to the solicitation of all the proprioceptive afferents whose effects

are highlighted:Bosco 1996

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•on locomotor and muscular apparatus

•on neuromuscular, neurohormonal, circulatory system

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Vibration plates, likewise handlebars, weightlifter bars, and vibration cables allow to apply to the whole body or to its different parts a gravitational overload, by means of elevated and reiterated accelerations.

These accelerations are similar to those that are obtained with workouts that involve muscular plyometric contractions, namely concentric contractions preceded by an extremely fast stretching of muscular fiber (Bosco e Cotelli 1995).

Such modifications of neuromuscular response, together with hormonal variations, are connected both to the sort of work done and to the speed of execution. (Guezenec et al. 1986 - Bosco et al. 1999 )

Years of experience in the use of vibration as a means to improve the performance have led to the integration of training methods of fast strength, employed up to now, with systems suited to produce vibrations.

This has allowed the formalization of two methods that integrate the characteristics of the vibration and those of heavy resistance training, where the load effect is determined one time from a physical overload (barbell) and another time from an isometric opposition.

“Variable Speed Method”

Since many years, one of the most used systems to train “cyclical fast strength” is the result of experiences and discussion sessions conducted with Prof. Vittori, and goes under the name of:

“Variable Speed Method”

Bonomi-Vittori

In 2005 an announcement has been made, published later on on “Athletics Studies” n°3-4/2006, that, though directly referring to speed, it’s indicative of an operational philosophy that can easily be transferred over different realities.

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Such method sets itself the goal of:

raising the peaks of the various strength expressions and, as far as possible, of decreasing their manifestation times.

Method objectives

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It also offers the great advantage of shortening translation times of strength capacities into capacity to perform quick movements, compared to a “sequence” execution.

so that methodological difference, in order to favor higher speed, will be accomplished, one time, through the load decrease, and the other time, through the diversity of the knee-bend. Whatever the choice made, the two exercises alternate. The one with high load is performed first, due to its greater influence on the strength, followed by the other which best stimulates speed.

1) load halving, in the alternation should the same exercise be used

2) work angle spread to the knee, as it appears from the three positions: squat, horizontal squat, and ½ squat

The dual requirement of strength increase and of its manifestation speed, is met concomitantly during the same training unit and for each different expression choosing, each time and according to the athlete needs, one of these two options:

Methodological strategy

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Used means

draw on three exercises:

1) The full squat = lower limbs maximum bending

2) The parallel squat = partial bending with horizontal thighs

3) The half squat = semi-bending with thighs at 90° to the knee

It’s easy to understand that the only passage from the full squat exercise to the others, maintaining the same load, allows a higher execution speed provided that, during the execution, effort intensity is always kept to the maximum. R

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Animal model; Rubin et al., 2001, Nature

About 10 years ago, since I was not very satisfied with the results achieved on elite sprint runners with the use of natural load vibration, in accordance with Prof. Bosco, I started to experiment with the use of means that reproduce the variations of gravitational forces through the application of mechanical vibrations (vibration plate Nemes) in addition to overload exercises. These systems had been utilized, in the past, in the field of clinical medicine, where vibratory stimuli were applied to study the response of neuromuscular proprioceptors to the induced mechanical perturbations.

Frequenza (Hz)

EM

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itrario)

Electromyographic response of the anterior tibial subjected to variable frequency vibratory stimuli

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During vibration training both the body and the muscles undergo small length variations (stretching-shortening). The fast pre-stretch of an electrically activated muscle helps the myotatic reflex stimulation with the consequent increase of muscle power out-put during the subsequent concentric phase. (Burke & al.) Vibration reflexes mostly or solely act directly on neuron motoneuron (alfa), not using the same efferent duct of cortical origin, as it’s usually the case during a voluntary contraction. Carmelo Bosco, Atko Viru and Roberto Bonomi’s studies (1993-1998) have shown that, in the presence of vibrations, human neuromuscular apparatus produce adaptive responses, both of metabolic and mechanical type, on muscular stiffness.

During ½ squat exercises with an overload equal to half of the body weight, national sprint runners have been observed accomplishing acute improvement of jump performance from 7% to 10%, when exposed to vibration training. Moreover, also the mechanical power of leg extensor muscles increases during parallel squat exercises performance, with an overload equal to 150% of BW during the vibration stimulus exposition.

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Roberto Bonomi

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The Maximum Isometric Force (MFI) has been achieved turning to the lower limbs maximum force in bending position, with the help of the arms put in counter-resistance over a bar. In short, pivoting on the hands it is possible to exercise a mainly isometric “hyperforce”.

Detail of the Vibration Plate with handlebar suited to create the

“MAXIMUM ISOMETRIC FORCE”

In the second method, that goes under the name Bonomi-Cotelli, the load effect is determined by an

isometric contraction

EMG and mechanical movements of

“vibration plate with handlebar” (MIF) recording

Contrazione Massima Forzata (CMF)

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During the Maximum Isometric Force phase with 35 Hz vibration, the average activity of VLsx has improved by 48%, that of the VLdx by 52%, while the average activity of VMsx has improved by 21%, that of VMdx by 23%.

Electromyographic analysis (EMG)Analysis results show that the Maximum Isometric Force (MIF) best operates and controls the vertical movement of the plate (damping) when ranging from 25 to 35 Hz; within this range the individuals are able to effectively oppose the vertical movement of the vibration plate. When higher frequencies are used the command of the vertical movement becomes more and more difficult instead.

Beyond 35-38 Hz, in most cases, the individual suffers the vibrations, and therefore the training proves to be less profitable.

During the Maximum Isometric Force (MIF) phase, the EMG average activity of Vastus Lateralis and Medialis can increase from 100% to 200%.

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In order to have a high biomechanical efficiency, all the involved muscular groups have to work in a very coordinate way, that is to say the agonist muscles have to contract quickly, while the antagonist muscles have to totally relax, except when the necessary braking must start.

Such remarks show that the most effective training condition proves to be that in which the athlete is able to fully control the machine movements: the higher he suffers the machine vibrations, the lower the resulting biomechanical efficiency, both for training and rehabilitation.

If that doesn’t happen, a phenomenon called “co-contraction” occurs, during which the antagonist muscles, not perfectly relaxed, obstruct the agonist muscles force expression, leading to a decrease in the efficiency of that movement.

These results are expression of a neuromuscular phenomenon difficult to clarify.

It is possible to deduce that either method involve, most likely, the neuromuscular system on its central and reflex nervous structures beyond the natural activation threshold.

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“A volte mi chiedo come sia accaduto che sia stato io a formulare la teoria della relatività. La ragione, credo, è che un adulto non si ferma mai a riflettere sui problemi dello spazio e del tempo, perché queste sono cose su cui ha pensato da bambino. Ma il mio sviluppo intellettuale fu tardivo, e di conseguenza io cominciai a interrogarmi sullo spazio e il tempo quando ero già adulto.”

A. Einstein

Thank You For Your AttentionRoberto Bonomi

bonomi_roberto@fastwebnet.it