I have just finished my first "proper" 4x7 cycle. The 4x7 exercise protocol comes from the work of Scott Sonnon and is based on the concept of a 28 day series of micro cycles designed to increase specific physical abilities rapidly. The beauty of the cycle is that it allows for enough rest and compensatory exercises as well as pretty intense training sessions in 7 four day cycles. My just completed 4x7 was focused on maintaining the endurance levels I have achieved via GS training as well as re-building some of my lost strength.
I am pretty satisfied with the results. When I started the 24kg kettlebell was "heavy" and used as my strength building tool. Level 1 of the AKC protocol was my endurance and metcon tool. Having just completed the 4x7 my strength tool is now the 32kg bell and I am up to level 4 of the AKC protocol. The 4x7 protocol clearly works for me (and I'm pretty sure will also work for most other people). One of the important things I have learnt is the value of allowing your body to offload the tension generated by intense training.
Tomorrow I'm starting my next 4x7 (this time even stricter than before) that will be focused on fat loss. To this end I will employ the fat loss program from the BWER ebook as well as kettlebell training. Hopefully I can get rid of some of the baby fat once and for all (not that a 38 year old should see himself as carrying baby fat - but then again, whatever).