Hello Graeme,
I've just checked some of the exercises and have found some discrepancies, (not that I was looking for any mind you).
Example: under the shoulders' section, we have two exercises, namely the dumbell flyes in two variations, (different angles). We're told that the primary muscle activated is the shoulders, and the secondary muscle is none. The correct answer is the primary muscle activated is the pectoral, whilst the secondary muscle activated being the anterior deltoid.
I'm not sure if I should even be making a comment in this thread, if no, then by all means delete this post if you wish. Thanks.
Fadi.