Originally Posted by lkjlkjlkj
"Note, there is a "No-Man's Land" between Z3 and Z4. Training in this
area has been found to not be beneficial for either the aerobic
requirements of Z3 or the LT/AT training in Z4.
This is not generally accepted as true and there is good evidence to the contrary. Many believe the border between Z3 and Z4 allows the greatest adaptation from maximizing the product of training time and training effect.
http://www.pezcyclingnews.com/defaul...lstory&id=3232