Well as I got better at swimming, I upped my distance too ... so I cover more distance by going faster and its more enjoyable too. It also upped my top speed,

Well as I got better at swimming, I upped my distance too ... so I cover more distance by going faster and its more enjoyable too. It also upped my top speed, allowing me to swim with the better swimmers without getting in their way, also adding to the enjoyment. A lot of swimmers do interval training too - eg 20 by 4 lengths every X minutes (with X including some rest time) - as you get better you drop the minutes to give yourself less rest and can up the number of intervals too. I guess its all down to enjoyment to swim more efficiently, as you counter the energy savings by going faster and longer ... Its like the pleasure you get from programming in a language you are expert in vs the one your just learning (which is rather frustrating until you get good at it and don't need the manual every two minutes!).