Where can you find "Efficient Heart Rate Training" ?
I'm a slacker.
Sorry, but it's true. I am. I announce things and then I forget to talk about them when they are released.
So, to repair things : I did write a few months ago a book on heart rate training that's avaialble on iBooks and Kindle.
If you're on a mac, an iPhone or an iPhone, you can use this link to review and buy the book in iBooks.
If you have a kindle or prefer Amazon, you can use this link.
Both of them are affiliate links, but given the price of thes book, I don't expect to retire tomorrow ;-)