Nonsense. If you think you're strong but you're not fit enough to do proper cardio then you're not really very strong. I do fasted cardio every morning 5 days a week and have since last June. Since that time my output has increased by 50%. My weight training has also increased; I'm squatting & deadlifting 50 lb more. Oh no wait, I forgot, all that cardio has hurt my gains! Yeah right. Long story short, don't be a pu**y. Fitness is fitness, whether you're moving weight or hauling shell it's all the same. Busting your ass is what gets results, not tip toeing around being scared to work hard because it's going to 'hurt your gains'.