I have always operated with the rule if I can't train for at least an hour (bike) it's not worth bothering. Lots of people seem to rave about the short duration, high intensity training such as this 20 minute one on GCN
View: http://www.youtube.com/watch?v=gGGvKt8vWho
What do you experts reckon?
View: http://www.youtube.com/watch?v=gGGvKt8vWho
What do you experts reckon?