Just had a look at the Kettlecise site, seems a lot of self publicity on there 'best UK Kettlebell trainer', always wary of that. From browsing over the site it looks to me like a fat burner (but that's diet anyway), but if you have been on 8kg for a year, there is little progression. Simple & Sinister is a GPP prog, designed to slowly build all over strength and conditioning which is achieved by focusing on technique and reducing the rest gaps over time, you 'own' the KB your are on at the time then move up. The swings are 10x10 for a reason (Alactic energy targeting power/endurance). Check out the book and reread, it explains everything much better than I will. At somepoint you'll get the 'WHAT THE HELL EFFECT', you'll go for a run that would previously have exhausted you, only to finish it fairly easily and not out of breath WTH! I've had this.