Cross training
Varying the activities you try and alternating them with weights, circuit training and aerobics can dramatically increase fitness. It will help to train complementary muscles, maintain cardiovascular fitness and give your joints and bones a welcome rest.
Variety also helps to prevent burnout, and if you are a swimmer they will also give your skin a break from salt or chlorine.
Speed training
If you have a specific target, speed training can help you go faster, and more efficiently.
When cycling
to get the most out of a session, freewheel for about ten minutes before and after speed work and treat hill workouts the same. Once a week find a hill that takes between 30 and 60 seconds to cycle up. Cycle up, freewheel down and repeat six to 10 times. Warm up and cool down for 10 minutes.