Monday, March 28, 2011

Cutting, Faking and the Biomechanics of Shooting

When a forward is one-on-one with a defender, cutting and faking is an integral part of creating a scoring opportunity. In many cases, the forward fakes one direction then moves the ball in the other before attempting a shot. A successful move frees the forward and allows him or her to attempt a shot on goal. However, these lateral movements can change the approach angle and speed of the player immediately prior to the kick, both of which could affect the velocity of the shot. Researchers from the Laboratory of Neuromechanics at the Aristotle University of Thessaloniki addressed this question. They looked at player biomechanics and velocity of shots taken after players attempted a typical cutting maneuver. They found that while such a move may free the shot taker from a defender, the quality of kick is affected.

A group of experienced U14 players were used in the study. They were asked to take a series of shots using the instep of the foot. Half of the shot were taken using a straight-on approach and the other half were taken after a double “faking” cutting maneuver. For the right-footed player, this later task was done by cutting to the left, back to the right, then placing the support leg near the ball for the shot. For the straight-on shots, the same number of approach steps was taken before the ball was struck. The shots, straight-on or cutting were done five times each, in random order.

The main finding was that the velocity of shots taken after the cutting maneuver was reduced by 12% compared to the straight-on shots. This was accompanied by reduced velocity of the swinging leg (the right leg for the right-footed players).

The cutting task also changed the biomechanics of the kick. During the period when the kicking leg is swinging through to strike the ball, the cutting task resulted in greater hip adduction. This it, the kicking leg swings through slightly closer to the support leg. Also, the ankle, which is normally locked in a neutral position, is in a more inverted position following the cutting task. This means that the outside or lateral border of the foot is slightly lower than the inside or medial border (i.e. the foot is “turned in”). This clearly changes the way the ball is stuck. With the ankle in a neutral position, he ball is struck with the instep and upper portion of the foot. In an inverted position, the ball is likely to be struck with the lower, top portion of the foot. This change in foot and hip orientation may explain why the shot velocity is reduced after cutting.

The results show that when young players perform a cutting task immediately before shooting, they alter the biomechanics of the shooting motion which, in turn reduces shot velocity. The authors of the study are quick to point out that while shot velocity may be reduced, their data do not necessarily mean that cutting reduces performance when taking a shot. Velocity is only one component of a successful attempt on goal and the most powerful kick is not always best. Whether the cutting maneuver alters accuracy of the shot remains to be seen. It is possible that altered mechanics and slower limb velocities may lead to a more successful shot. It is also possible that changes in foot position when the ball is struck can alter the spin and flight of the ball which may increase the odds of scoring. Certainly if cutting maneuvers free the shot taker from an opponent, then the chance of success are increased.

The authors also suggest that players should training to improve their ability to execute a cutting maneuver. This will likely have two key effects. It will increase the likelihood of pulling off the move and freeing the shooter from a defender. However, it may also improve the quality of the subsequent shot. Focusing on proper shot mechanics after cutting may eliminate the reduction in shot velocity. In the end, both creating a scoring opportunities then capitalizing on those opportunities are both important components of scoring a goal.

Reference:

Katis A, Kellis E (2011) Is soccer kick performance better after a “faking” (cutting) maneuver task? Sports Biomechanics, 10:35-45.