Dr. Patrick: What about stretching? That's something, you know...I see people stretching in the gym, they're stretching before a set, they're stretching in between sets, after working out. What role does stretching play, I mean, in muscle-protein synthesis or muscle hypertrophy or injury or anything? Flexibility, anything.

Dr. Schoenfeld: Yeah. So, I'll approach it from different levels, but, on the basic level, most people think of stretching from a flexibility standpoint. Do people need to stretch? If you need more flexibility then it would be beneficial to stretch. Stretching for the sake...or I should say this, gaining flexibility for the sake of gaining flexibility is misguided because increased flexibility reduces the stability of the joint. So, if you can do what you need to do from an activities-of-daily-living standpoint, from a mobility and flexibility stuff, no reason to gain more flexibility. If you are, let's say, a punter in football, you're going to need to be able to get your leg very high, or a rockette in the Radio City musical, they would, you know, necessarily want to do, if they're not able to do it, or even to continue doing it, to do some type of flexibility training. But for the majority of people that's not an issue. So, everyone has to assess their own flexibility needs.

With that said, resistance training itself is a active form of flexibility training. And there's been studies that show that, compared to static stretching, you get similar benefits doing resistance training protocols, provided that you're training through a full range of motion. So, if you are lifting weights, total body, through a full range of motion, you get similar benefits to static stretching. Combining them is even better if you want to add on your flexibility. So, if you don't think you've gotten enough flexibility from your resistance training and you need more from an ADL-activities daily-living standpoint, then go for it.

Now, I'll approached this also from a muscle protein synthesis, this is actually quite interesting. I'm collaborating with a group from Germany and they actually have other research that's recently come out showing that, long-term, if you stretch...now, this is a lot of stretching, but they did an hour a day using a stretching boot, they got marked hypertrophy, like 15% growth in the calf muscles and the muscle thickness. Really interesting. Now, I don't know who wants to use a stretching boot for an hour a day but it just shows that stretching...I mean, there is tension during the stretch and that tension, muscle tension, is a mechanism of hypertrophy. So, doing long-duration stretching...and these were intense stretches that were like an 8 out of 10 on the discomfort scale, so, not a fun thing. So, it's not like, "I'm stretching," you know, they were fairly intense stretch.

So, it does show that stretching itself can have an anabolic effect. We recently published a study, and there was some papers before this also showing this, that what's called inter-set stretch, loaded stretch promoted somewhat greater gains. We used it in a calf exercise. So, basically, subjects did calf raises, what's called plantar flexion, for their gastrocnemius and soleus, which are the two calf muscles. And this was actually within subject design where one leg they just rested for 2 minutes between the sets, they did their calf raise and then they rested for 2 minutes. The other group, the other leg they would do their set and then, immediately after the set, they would descend into a stretch with the weight still on. So, basically, it was a loaded stretch. And that's intense. I mean, you know, they were kind of hurting at that last...or doing what they could to endure towards the end of the stretch. And they did it for 20 seconds and then they rested for the rest of the rest interval.

And we found somewhat greater growth in the soleus muscle and really no difference, no substantial difference, in the gastrocnemius. Now, interestingly, the soleus is a type-1-dominant-fiber muscle, that's about 80% slow-twitch type-1 fibers. So, it kind of raises the possibility is the stretching, at least the loaded stretching that we do, are more specific to type-1 fibers than type 2. Not sure.

Dr. Patrick: All this talk makes me think about yoga. And, I mean, yoga, I mean, it's stretching but it's also, like, pretty intense, I mean, you're holding a pose and your muscles stretch. Like, what are your thoughts on yoga? Do you think you could extrapolate a little bit?

Dr. Schoenfeld: Yeah. So, now, again, I'm not a yoga specialist but I do know something about it, and there's different forms of yoga, some have more, quote unquote, strength-related focuses within them. You certainly can gain muscle from yoga but is it going to optimize muscle? No, because again, as a general rule, at least from what I know through most of the forms of yoga, you're really not challenging over time...maybe at the beginning, when you're a newbie, that's where you're going to see your gains, but, over time, you don't challenge the muscle sufficiently to need to adapt. So, you will plateau rather quickly and you'll maintain. So, you can get some gains at the beginning. Can there be ways that you might adapt or altered the yoga principles to doing that? I would guess but I'm not familiar enough with the strategy, you know, to say.

Dr. Patrick: So, maybe yoga shouldn't be used instead of a resistance training but in addition to would be nice...

Dr. Schoenfeld: That would be correct. If you want to optimize...again, resistance training is paramount. All of these other things are potentially beneficial...and, again, if you have all the time in the world, do them all, to the extent, I should say, as long as you're not overtraining, to the extent that you don't overtrain within your body's capabilities, but I think, if you can only do one, my objective, a somewhat biased view, is that resistance training is irreplaceable.

Dr. Patrick: Yeah, there were some people that were kind of, you know, mostly women wondering, "Oh, can yoga be considered resistance training?" and I was thinking about it, like, "Oh, no, that's a good question." Because, you know, I could, in my head, come up with the way when, yes, it would be. So, that is good to know.