When people talk about footballers and hurlers, pace is often one of the key traits associated with good players. However, the ability to slow down or stop can be just as critical. Here, DCU Football Academy conditioning coach Julie Davis, explains the importance of ‘deceleration'

DID you ever notice how a good player can make space by stopping quickly, leaving an opponent flailing in the process? The ability to speed up and slow down quickly can make the difference, particularly to those players isolated at corner-back and corner-forward.

There are many elements to sports - speed, acceleration, maximum velocity, speed endurance, agility and deceleration. If acceleration is the body's ability to overcome inertia from a standing start, deceleration is the body's ability to control speed in the presence of momentum. A good forward can be hurtling towards goal but it's often the ability to stop and turn the defender that creates the scoring chance.

How often have we seen players like Colm Cooper or Steven McDonnell leave a defender on his behind and have pundits attribute it to a wonderful ‘shimmy', skill or sidestep? However, in many instances, this is down to the player's ability to decelerate. To put it technically - momentum is the product of the mass of a moving object and its linear velocity. As speed increases, momentum is amplified, which means that it will take a greater muscle force to control, decelerate, or stop it.

The concept of duality is a strong one within the world of strength and conditioning. Sir Isaac Newton could have been on to something when he stated his third law! ‘For every action there is equal and opposite reaction'. This concept can be used to explain the movement of deceleration.

When the body accelerates from a standing start there is a powerful extension of the ankle, knee and hip, this is commonly known as the triple extension. As the player overcomes the inertia of their own body mass there stride length increases as their centre of gravity rises.

However when a player has to decelerate, the opposite occurs; the player has to control the momentum that the body has generated as their speed has increased. Flexion occurs at the ankle, knee and hip, stride length shortens and the centre of gravity lowers, the finish position is the athletic stance position.