weight training

Hello from from the UK. I have only just found this forum and it really is a pleasure to read up on the wealth of knowledge on show here. I have been a lds for 8 years now, my favourite distance being 10k and over. Before that I was a powerlifter so I was heavily muscled and although I haven't lifted a weight since those days and am now a lot smaller I am still quite muscled (due to swimming). The ow season starts over here at the end of May and I was thinking of starting a 3 day a week high rep weights program concentrating on all the major muscle groups. However my concern is that, with my past I may become muscle bound (even with high reps) as I have retained quite a lot of muscle (ie 17 inch arms, 44 inch chest etc). Atm my weekly dryland training consists of stretching and 3x20 min on the turbo trainer. If anyone has any advice as to whether a weights regime would be beneficial for me then please post a reply. Any help would be greatly appreciated!!