Sue, I started doing consistent strength/core training about a year ago- just after my 3rd baby was born (being pregnant and chubby is a great motivator for me!). I had weights at home and mostly worked on my arms and abs and I can't tell you what a difference I felt when I ran Boston 4 months later and Green Bay the month after that. I have never felt so strong throughout an entire race as I did with those two. I sort of slacked a little with the strenth training during the summer and noticed that I didn't feel nearly as strong during my fall marathons. I've been using machines at a gym for the past 3 months again and feel great. I'm not sure how long I will lay off the weights prior to Boston this year but I suspect that I will lift about 5 days before the race and then not again until a week after. My personal opinion is that 5 weeks is a little long so maybe you should play that one by ear. There really should be no reason why you couldn't strength train up until 2 weeks before your marathon and then take it off if you want a taper. What does your gut tell you to do?