There are various views on rest days and this also has a lot to do with what your training goals are, but what I learned, especially at the end of last year, is that rest is ESSENTIAL. We are human and as addictive as training can become, without recovery, the body and mind does not have a chance to rebuild itself without rest. In order to make ourselves stronger, we push the body to the limits. This involves literally tearing the muscle (minor tears) and then with recovery, the muscle will then grow back stronger and faster. In addition to this, and those of you out there who have been training hard for any long period of time will know exactly what I mean, the brain starts to fatigue as well. When training is constantly tough without improvement, this plays on the mind and therefore performance. If you are not mentally strong, you can never reach your full potential. So if you need a rest, not because you can't be bothered but you are physically and or mentally fatigued, rest. Go for a walk, go to the beach, have quality family time and step out of the triathlon bubble just for a moment. You're next training session may just surprise you.