Dr. Patrick: That's another area that I was wanting to talk to you about was the combination of aerobic exercise and strength training and the effects on muscle hypertrophy, combining them maybe even just either with, like, days...so, you do strength training one day and then aerobic exercise the other day, so, that's kind of a little bit it seems like what you're talking about, having the blood flow to help with recovery or soreness. But also, what if you do it on the same day, the same session even?

Dr. Schoenfeld: Yeah, so, there's been a lot of talk about concurrent training being detrimental, there was something called the chronic interference hypothesis, which, basically, was actually shown in animal models, in rodent models where the intracellular signaling for cardiovascular exercise upregulated your catabolic pathways, your AMPK pathway. Again, I don't want to get too technical here but the AMPK is a catabolic pathway which actually blunts the mTOR pathway, which is an anabolic pathway. Alternatively, your resistance, your anaerobic exercise was your anabolic pathway, thus, if you did aerobic training, it would blunt the adaptations for resistance training. And that actually has been shown to be at least, at the very least, a way...oversimplification.

Now, at some point, there will seem to be some interference but it does seem that that point is a lot further along than what we originally had thought. And I think that more has to do with the overtraining effects than probably the intracellular signaling effect, so, it's not clear. But we have some pretty good meta-analytic data now showing that, within, you know, decent volumes of training, there does not seem to be a blunting of the anabolic effect, and that's even when it's performed in the same day.

There was some evidence that perhaps, even at somewhat higher levels, that maybe there was a negative effect on fiber type-specific, particularly on the type-1 fibers. Again, I think it's a little premature to draw strong inferences on that.

But what I would say is I think the general recommendations that I would make from the literature that we have, like you said, if possible, space it out so that, if you're doing resistance training Monday, Wednesday, Friday, you want to do six days a week of training, do your aerobic training on your alternative days, Tuesday, Thursday, Saturday. If not, possibly do a morning afternoon-type thing, or evening, where you do, let's say, resistance training in the morning, cardio in your evening. And at worst, if you have to do them in the same session, always do the resistance training first because, if nothing else, the aerobic training can compromise your energy levels to do the strength training, it can compromise the performance. So, that in itself would have a negative effect, if you're going to compromise performance, on your results.

I do also want to point out that this is, again, a very nuanced topic. So, how much resistance training are you doing, how much aerobic training? So, particularly with the aerobic training, are you doing long slow distance? Are you doing six days a week of marathon running training? Yeah, that's going to certainly start to have negative effects on your muscle development. If you're walking 10,000 steps a day, 12,000 steps a day, very unlikely that's going to have any negative effect. If you're doing three high-intensity interval training sessions per week, very unlikely that's going to have a negative effects. So, there's a spectrum on these things. These are not yes-or-no questions that I can give a cookie-cutter response but, on a general basis, you need to I think, at the very least, be in tune with your body. And that's, to me, one of the most important things I can communicate to the audience is to really start to be in tune with your body. If you feel you need extra time off, you're probably overdoing it. And I think a lot of times people are just oblivious, they get into a routine and it's just, "I have to do this, I have to do this." And try to be intuitive, use your intuition. And, you know, if you think you need a day off, take a day. If you think you need two days off...

Deload periods, when done properly, can be beneficial where you're having periods of reduced training frequency, particularly if you're training very hard. If you're doing the typical type of workout that most gen pops do, you probably don't need a deload because you're not training hard enough to warrant that. But certainly, if you're very serious exercisers, bodybuilders, particular in high-level athletes, interspersing regimented periods of reduced training frequency, volume, intensity I think are very important.

Dr. Patrick: How do people that are endurance athletes, like, that are training for a race or whatever, do that? I mean, like, can they still incorporate their resistance training in their, obviously, very extensive endurance-training program without over training. Is it even...

Dr. Schoenfeld: Yeah, yeah. So, one thing I would say for endurance...so, endurance-training athletes encompass a fairly wide spectrum. But let's take your typical runner. So, when we're talking endurance, cross-country, you know, doing a marathon-type running or long-distance, cross-country, weight is an issue. So, you want to train in a more minimalist fashion because higher-volume programs will tend to put on muscle mass. You want to try, as an endurance-based athlete, to reduce muscle-mass development and maximize strength development. And that would be using heavier loads. So, that's what you don't want to do, your light-load training with higher volumes. You'd want to focus more on your, let's say, three to five-rep training for a few sets. So, the volume will be insufficient to substantially increase muscle mass. So, volume is a driver of hypertrophy.

And if you're doing low-volume training with heavy loads, then, generally speaking, you're not going to gain much weight in terms of muscle mass but you will be able to get the benefits that will help you optimize your endurance capacity.