SPORTING "OVERHEAD" GESTURE: TECHNICAL-SPORTING IMPACT FACTORS - SPORT-AND-HEALTH

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"Overhead" sporting gesture: functional and technical-sporting factors of incidence

Edited by Doctor Alessio Capobianco

Technical-sporting factors: characteristics of the object of the throw, use of tools, constraints imposed by the competition regulations

The characteristics of the thrown object (weight, volume and shape) are variable according to the sports specialties considered.
The use of objects of moderate weight and of small volume, such as the baseball, or of aerodynamic shape, such as the javelin, allow the sports "thrower" to reach such high values of angular velocity at the shoulder level as to be theoretically incompatible with its stability; the mechanisms capable of limiting this incompatibility are the correct mode of force production (of fast force or explosive force) and an "intense antagonistic muscle action; this action manifests itself in an eccentric mode of contraction, which represents a greater risk factor than the concentric one. Therefore, the greater the possibility offered by the characteristics of the object to accelerate the arm, the greater the corresponding risk factor seems to be.As the weight of the object increases, the athlete's demand for muscle strength increases, as does the opportunity to exploit the plyometric muscle contraction; the "optimal production of force requires, in turn, an" adequate joint mobility and a "suitable space-time construction of the sporting gesture.

The use, in sports practice, of propulsive gear (type of equipment that serves as an aid in the movement of the practitioner the "sporting activity in space) does not seem to be of particular interest in the shoulder pathology; the sailing specialty called" windsurf "perhaps deserves further study on the overload pathology, even if the recent evolutions of technology and equipment seem aligned with logical criteria of ergonomics.
The use of impulsive tools, on the other hand, (a tool that in sports practice is subject to one or more impulses by the practitioner and does not act as an adjuvant means in moving) determines an increase in the moment of inertial force, increasing the stresses imposed on the stabilizing structures of the shoulder; an example of an overhead technical gesture performed with impulsive tools is the serve in tennis. This brings attention back to the "importance of" adequate joint mobility, "suitable muscle elasticity, coordinated agonist action and" effective antagonist action.
The regulation of some sports specialties implies the existence of conditions that can increase the pathogenetic risk for the sportsman's shoulder; these conditions may be linked to the modalities of interaction between the sportsman and the other individuals involved in the activity or between the sportsman and "environment in which the sporting specialty takes place.
Among the conditions linked to human interactions, the modality of opposition between opponents in team and contact sports assumes importance, for the epidemiological incidence; these conditions, however, seem to have greater weight in relation to the incidence of acute disease than in that of overload or chronic pathology.

Among the conditions linked to the environment, the characteristics and methods of use of the support base may be important; the latter constitutes the constraint on which the kinetic chain rests; these conditions may be of some importance in increasing the pathogenetic risk of overload; in volleyball, for instance,

the presence of the net in front of the attacker, together with the prohibition of touching it during the action, implicitly determines the presence of a greater antagonistic muscular action, precisely to avoid unwanted contact with the net; although the attacking action takes place in elevation, this constitutes a factor of greater balance between the agonist and the antagonist action which could explain the lower epidemiological incidence observed in this overhead sports specialty compared to other similar ones in which the " incidence is greater.