Hookers have to be extremely fit as you're expected to be very mobile around the pitch.
Some people are naturally fit but unfortunately, I'm not one of those people!
Steve Thompson's facts
Born: 15 July 1978, Hemel Hempstead
Club: Northampton Saints
England debut: 2 Feb 2002 against Scotland
Height: 6ft 1in
Weight: 18st 7lbs
I've been lucky I've been blessed with my size, but it means I'm battling the fat all the time trying to keep my weight down.
I have to really work hard on my fitness, but it's paying off.
I'm now more mobile around the pitch and I've even found myself at fly-half on occasions, but Will Greenwood keeps telling me off when I end up there!
I used to be a loose forward, but my former coach at Northampton, Ian McGeechan, suggested I should move to the front row a few years ago.
I played prop for a while, but that seemed too much hard work for me.
Playing hooker is the best of both worlds.
I'm right in the middle of the scrum, but I can also run around all over the place like a loose forward.
Throwing takes up a lot of my time. I throw every single day.
I keep practising, getting my timing right, along with the spiral, working with England specialist throwing coach Simon Hardy.
I owe my international career to Simon. If it wasn't for him I wouldn't be in the England team now.
Thompson takes aim
I went on tour to the USA and Canada with England a few years ago when I first met Simon.
My throwing was bad - I couldn't hit a barn door!
He taught me how to throw properly, things like technique, where my elbows and hands should be.
He also taught me about the importance of timing and hitting my targets.
We have people who call the line out and their job is to give the coded call so the hooker knows who to throw the ball towards.
In the scrum you work with the scrum-half, working on things like when to put the ball in and timing the strike.
The scrum-half usually gives me a tap so I know when the ball is coming in.