I place that qualifier before everything I read about training, you'd be a fool not to.
Edit to add: For example, one rule of thumb says you should ride an Ironman at 73% of FTP. Well if you haven't trained appropriately to ride that hard, boom goes the dynamite.
Edit to add: For example, one rule of thumb says you should ride an Ironman at 73% of FTP. Well if you haven't trained appropriately to ride that hard, boom goes the dynamite.