Estudio de la fuerza y disposición del core de los paracaidistas acrobáticos del ejército del aire

Résumé

Introduction: The concept "core" makes reference to the central core of the body, to the trunk and specifically to the strength of its muscles and the morphology of the rachis. Up to the present, these variables have been studied in diverse populations but not in parachutists. The group of parachutists with the highest level is made up of the Air Force's Acrobatic Skydiving Patrol (PAPEA). Its members are subject to specific exercises and activities which cause stress, which could determine some changes, adaptations or cousequences on the disposition of the rachis. Goals: Describe the sagital curves and the mobility of the rachis concerning the members of PAPEA, besides analising the elasticity of their isquiosural muscles. Establish the strength of the trunk and lower extremities by relating it to the sagital disposition of the rachis and determine the relations among the sexes and anthropometric variables. Material and method: A cross-sectional study was carried out, in which the fourteen members of the PAPEA (five women and nine men) aged 34 took part. Measurings of saggital rachis were carried out by achieving degrees of kyphosis, lordosis and lumbo-horizontal angle. Kyphotic and lordotic indices were calculated. In addition to the data gathering on isquiosural extensibity and the strength of trunk and lower limbs. For all of this, plumb, goniometer, inclinometer UNILEVEL, drawer of flexibility sit an reach, dynamometer for trunk and Spinal Mouse¿ were used. The assessment was conducted in two positions: standing and sitting in two categories: usual attitude and hyperextension of trunk. Besides, by means of Spinal Mouse¿ measurings in specific positions of the skydiving activity were carried out. Results: Forty-two percent of the population present changes on the saggital plane (two individuals with hyperkyphosis and four with hyperlordosis). Generally speaking, kyphotic attitudes are predominant in males and lordosis in females. Concerning Spinal Mouse¿, we can find some significant differences in the sex as for lumbar curve in the standing position (p=0,023). Women have superior values in global amplitude of the rachis movement. Individuals with more kyphosis in a standing position make less motion than those who are in the normality range when bending their trunk, but in the decubitus extention their range of movement is bigger. We can notice some significant differences in the amplitude of the maximun flexion and between the common position and the decutitus one on a skateboard. We can find a good relation among the different assessment systems of the rachis. Individuals with shortening have not been found. There is a tendency that individuals with common lordosis have an "average" trunk strength and "good" an "average" limb strength. Conclusions: With the different methods of exploration which have been used, we can learn that about half of the parachutists presents alterations in their spinal curves. Most of them are dynamic curves or postural attitudes that can be corrected by means of a position change. Elasticity of isquiosural muscles of these parachutists ir found in the range of normality. The diferences on the values of absolute strength between men and wommen disappear when relativizing strengtth. There is the no connection among spinal deformities whith trunk strength and limbs. A relation between the anthropometric variables and the presence of unusual curves has not been found. Kyphotic attitudes predominate in the group of men.