The Influence of Isokinetic Muscle Torque Exerted in Various Speeds on Soccer Ball Velocity

Abstract

Soccer is one of the most popular, widely played sports in our societies with millions of participants all over the ~o r l d . '~,~~ Furthermore, soccer is a dynamic game featuring fastpaced activities and covering substantial distances over the course of the game. It is a physically demanding game which requires a high degree of technical skill, stamina, strength, and speed. In spite of this it is surprising that there are few scientific studies concerning the physiological profiles of soccer players. The powerful kick of a soccer ball should be considered an important factor affecting athletic ~erformance and, in addition to skillful exemetric contraction^,^^^^ as well as training at slow and fast isokinetic velo~ities;'~'~ while others have studied the effect of torque-velocity relationships and muscle fiber composition (fast and slow twitch) in elite athletes5 and strength training motoneuron excitability in human leg mus~ulature.~~'~ The aim of this study was to determine if the initial soccer ball velocity during a powerful soccer kick is related to isokinetic muscle strength of the lower extremity measured at various angular velocities: 30, 90, and 1 80°/sec. MATERIALS AND METHODScution, is the result of strength and speed.23 The Eleven Greek soccer players of the national Of strength and speed for improving team (four defenders, four midfielders, and three athletic performance is wellInforwards) were studied after their written consent vestigators have compared various strength trainhad been obtained. All athletes were tested on ing methods; concentric and eccentric versus isothe Cybex IIm isokinetic apparatus (Cybex 11, Division of Lumex, Ronkokoma, NY) at angular ve-

Kicking ability and kicking deficit in young elite soccer players

“…However, this study has been conducted with adults and, thus, it remains unknown whether KD already exists in young soccer players and if it is associated with neuromuscular skills, as previously shown in adults. Indeed, ball velocity increments associated with age are likely to occur not only due to the skill development of the kicking pattern, but also due to the increased absolute muscle strength associated with growth and maturation (Poulmedis, Rondoyannis, Mitsou, & Tsarouchas, 1988;Tol, Slim, van Soest, & van Dijk, 2002;Wong, Chamari, Dellal, & Wisloff, 2009).…”

Strength and Kicking Performance in Soccer

“…In addition, in young soccer players, a significant relationship between ball kicking velocity and the maximal isokinetic forces of the thigh and shank was found (38). In elite soccer players, ball velocity values after a soccer kick correlated significantly with isokinetic muscle torques reached at different angular velocities (51). These authors also reported that the intensity of the relationship tends to decrease with the increase in angular velocities.…”

“…Therefore, several studies have investigated the relationship between the ball velocity after a maximal soccer kick and the strength and power values of the lower limbs (10,13,15,28,30,38,(44)(45)(46)(47)51,60,61) as well as the relationship between ball velocity and the velocity values of linear sprint runs (15) and nonlinear sprint runs (13). Other studies have explored the influence of different strength training programs on ball velocity values after a soccer kick (1,10,12,27,(39)(40)(41)50,55,62,63).…”

Measuring running speed using photocells

“…Photocells have been used for m easuring speeds in various sporting activities, including golf, javelin, soccer, luge (Richards et al, 1985;Viitasalo and Korjus, 1987;Poulm edis et al, 1988;Br ggem ann and Kunkel, 1990) and running (Ikai, 1968;M ero and K om i, 1985;Ae et al, 1985;N igg et al, 1987). Although photocells are used routinely to estim ate running speed, little inform ation exists on the accuracy of such system s.…”