This article is from the Hardgainer Bodybuilding & Weightlifting FAQ, by Frank J. Kelly and Craig R. Sadler with numerous contributions by others.
No. If one exercise is gaining a lot, and
another is not, then stay with the cycle. Try to add 1lb to the
'sticking' exercise, or even 0.5lbs each week (possibly do the
'sticking' exercise once every two weeks to allow any other faster-
gaining exercise to keep on gaining). Pump every cycle for as much
gain as you can. In the end you may only be able to add 0.5-1.0 lbs
a week but keep it up and when these gains stop too THEN start over.
 
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