The A - Z of Sports Vision - Adrenaline

Adrenaline (Also known as epinephrine) is a hormone produced by the adrenal glands, which sit at the top of the kidneys. It has a number of functions, such as regulating our heart rate. But it’s particularly involved in our reaction to a threat or stress – the so-called “fight or flight” response. In sport, this can have a number of benefits. Blood is diverted from the organs that are no use in a fight, such as the digestive system (hence butterflies in the stomach), to those that are needed – the muscles in our limbs. Our heart rate increases, as well as our metabolism, enabling us to release more energy, especially from fats. All this is really useful for a fairly short burst of physical activity, but not so good for endurance sports or when you’re putting on a golf course. In the eye, adrenaline causes relaxation of the ciliary muscle, which results in a loss of ability to focus close objects clearly (accommodation). The pupil also enlarges, resulting in a reduction in our depth of focus. This can make it more difficult for an older shooter to focus on the sight of a gun. In more stressful situations, “tunnel vision” can occur. We don’t actually lose our ability to see to the sides, but attention tends to focus on a limited area, especially in the face of a threat. For a penalty taker, the goalkeeper can be perceived as a threat: indeed, goalkeepers seem to have cottoned on to this, and try and make their presence felt as much as possible. There are some times when a narrow focus of attention can be useful, such as a when a darts player just wants to concentrate on the board. For a rugby prop forward, there are times when it can be useful, such as when the scrum engages, but times when it isn't, such as when he finds himself in open play. So for optimal sporting performance you need the right amount of adrenaline – not too much and not too little. It’s therefore essential that players practice in competitive situations. They’ll still be up for the game, but will still be able to spot the killer pass to the player who’s unmarked. David Donner