What could be going wrong? Weight training for breaststroke

I am a breaststroke swimmer, have always been. Then I stopped for 6 years and have started swimming again for around 3 months now. Around a month and a half ago I was doing 16 times 50m in splits of 42-43 at a pace of 50 seconds ea with around 70% effort. Reading all the forums I since started doing more weight training around 2-3 times a week focusing mainly on upper body as I find that my upper body is quite weak and small compared to my legs. Now, I'm finding it extremely hard to do the same splits, and usually end up going 46-47 @ 50 sec pace after around 3 or 4 and feels more like 80% effort. Same thing with my 100 splits. Was going around 1.25-1.27 and now going around 1.30-1.35. Am I causing more resistance or is there a period when the body adjusts? And shouldn't I be going much faster as I can lift more weights for a better period of time now than when I started? How can I make the weight training effectively work for me? Does anyone have similar experience and how you overcame this?For reference: I'm following the advice from this thread including others forums.usms.org/showthread.php Thanks Weight training tires you out, most definitely. Your muscles do need time to adjust to the added stress you're putting on them. Please clarify the above set. Were you doing 16x50 *** on a 50-second interval and holding 42 seconds at a 70 percent effort? That's Olympic quality. I had to do sets like that in college, and that was at a top-level university! I don't think I did 16 of them, though. Also, keep in mind that you took six years off and have only been back for three months. Your body is trying to find its swimming shape again. If you are doing 16x50 on :50 now and holding 46 seconds, you are still quite an animal. I don't think any of the revered distance (i.e. 200) breaststrokers in Masters swimming can do that set.

Thanks for the reply and yes, that is what I was doing. And to be fair, I am 26 so just started thinking about Masters swimming. I train with a freestyle guy who does those sets and I just follow him with all his sets trying to keep the intervals that he does but obviously I'm slower as he does each 50 around 36-37. Also, your comment has made me think a bit. I think I find it hard to connect when I'm sprinting as my best 50m *** time is around 31 secs which I think is slow as the freestyle guys time is 24 secs and I know I'm trying much harder than him. I'm self taught, trained by a coach but he never touched my stroke. Do you think I should go look for help?

For anyone that may be wondering about the weight training. It seems like it was just a phase as my body was getting more used to it. Was doing splits of around 38-43 in the 50s and from 1.19 to 1.24 in the 100s this whole week at training so it seems my timings are improving. Also on a side note, getting highly impressed by Michael Jamieson's swim of the 200m in the Olympics as he's from the UK as well and he seems like a top bloke. Hope I can get some tips off him some day.