4 Juicy new studies on how to build muscle

Chapters:

00:00 Intro

00:05 1. Squat rep range affects muscles targeted

03:00 2. Leg extensions vs leg press

05:28 3. Cold plunges for recovery

06:50 4. Low starting muscle mass doesn’t make you a hardgainer

08:16 Outro

Transcript:

Bro, wake up! 4 new bangers just dropped on how to get jacked!

In the first study the researchers had a group of national level powerlifters squat with 70 to 90% of their 1 rep max in five percentage point increments. The researchers then estimated the muscular forces produced by every involved muscle group at each exercise intensity. The general finding was that squatting at heavier weights with a higher intensity led to greater force production, obviously, but the magnitude of this increase differed considerably per muscle group. In particular, the glutes experienced a far higher increase in muscular force production and higher weights than the quads. These findings suggest that the quads are almost always trained to a reasonable degree by squats, even with lower weights or training further away from failure, but as you gets closer to failure or you use heavier weights, the glutes become more and more involved. This was also seen in their biomechanics in that they were leaning forward a little bit more as they got to use heavier weights.

These findings are in line with some biomechanical analysis of bench presses which suggested that lower intensity bench presses stimulate the pecs very well, but the triceps mainly become highly involved as you get very close to failure or you use very heavy weights. So it seems that some of these compound exercises have a primary muscle group that is targeted very well, even if you don’t train that hard, but as you train very hard you start involving all of the musculature fully, which makes biomechanical sense, and the implication of that would be that you can target certain muscle groups more with different exercise intensities. So the muscle groups that are the most targeted, kind of the primary targets, they’re trained effectively even if you’re not training that hard, but as you get very close to failure or you use very heavy weight it’s all hands on deck and you’re involving all of the musculature pretty much maximally, as needed for maximum force production.

The major caveat here is that force production and in other research EMG muscle activity was analyzed with sub-maximal training loads. So in a practical training setting where people are going close to failure these things might not matter, and we need a long term study to see if you can really selectively target the glutes more by going heavier, for example, or if it’s the case that if you train remotely hard, these differences are simply too marginal to really matter in practice.

Another interesting finding was that force production in the hamstrings and the rectus femoris of the quads, basically the middle head of the quads was very low. These muscles have a bi-articular muscle conflict where contracting would sabotage one joint while helping the other. So these muscles cannot be recruited very productively during a squat and therefore they are not trained much. So squats do not train “legs”, they specifically train glutes and certain heads of the quads, namely the heads without the rectus femoris.

Before we get to study number two, just a quick note if you’re a serious lifter that wants to know everything about muscle growth and how to take their physique to their maximum genetic muscular potential, check out my online course in the link in the description below, and my app to put it into practice.

Now, moving on to study number two, where the researchers had a group of individuals perform leg extensions with one leg and leg presses with the other leg. After 12 weeks, based on gold standard MRI measurements of muscle growth, the leg extensions were more effective than the leg press to stimulate the quads, specifically the rectus femoris of the quads. There was no significant difference in the vasti muscles between the leg extensions and the leg press.

The rectus femoris, as we just discussed, cannot productively activate during a squat or a leg press. A leg extension, however, targets it very well. And in this study the researchers did not have the subjects lean back or recline during the leg extensions. You should. Previous research has shown that during leg extensions, if you lean back, recline in your seat, then you stimulate the rectus femoris of the quads more. You lengthen it and allow it to produce higher forces, more mechanical tension, and thereby you get more muscle growth in the rectus femoris. In a sense of the rectus femoris being trained more and the other heads of the quads not being trained any differently between leg extensions and like presses, ironically, leg extensions are a more complete quad exercise than the compound exercise, squats or leg presses.

Now I would note that some previous research has found that leg presses or squats grow the other vasti muscles better than leg extensions. In this study, that was not the case and I suspect that this is due to differences in the machine’s resistance curve and range of motion used. If squats or leg presses allow you to use more range of motion and go deeper, and this increases the mechanical tension on the other heads of the quads by virtue of being at longer muscle lengths, then they might be more effective. But inherently speaking, a leg extension, a leg press and a squat should be equally effective, again, given equal resistance curves and raised motion, for the quads.

This study also replicated the previous study finding that the hamstrings were barely trained by leg presses. The glutes, the quads, and the adductor magnus were trained very well by the leg presses, but the hamstrings were not. The final interesting finding is that the pattern of muscle growth, as measured by gold standard MRI measurements, corresponded very well with the pattern of muscle activity as measured by electromyography. If you have got your fitness education from social media, you might have heard that EMG has been “debunked”. This is certainly not the case. EMG has a lot of limitations, and you cannot directly extrapolate the results to muscle hypertrophy, but there are multiple lines of evidence that support that when properly conducted, EMG research does actually allow us to see quite well which muscles are involved in an exercise.

Study number 3 was a meta analysis of 30 studies on cold water immersion, things like cold plunges and ice baths, which have become very popular in recent years, as a way to promote recovery. I’ll add another new study here because it came to similar conclusions, namely that all of these things don’t really improve recovery. Cold water immersion did reduce feelings of muscle soreness, but it did not objectively improve the recovery of strength or power. Funny enough, these results did not stop the researchers from concluding that cold water immersion was in fact beneficial for recovery. And that’s why it’s so important to actually read the results of a study, rather than just a conclusion from the authors.

Based on the totality of research, I would actually say that post-workout cold punches and ice baths are a negative for recovery, because multiple studies have found that they can blunt muscle protein synthesis and muscle growth. Suppressing inflammation at some point becomes detrimental. We’ve also seen this with vitamin C and E supplementation, as well as with the application of certain painkillers – NSAIDs, in particular, non-steroidal anti-inflammatory drugs, that, beyond a certain point, suppressing inflammation actually also suppress as part of the recovery process, and muscular repair, and that subsequently reduces muscle growth. It’s important to realize that inflammation is a natural part of the muscular repair process. Fortunately, our bodies are very good at healing themselves. You really don’t need to do a whole lot to recover. Just Netflix and chill is the gold standard.

Study number 4, which was a meta analysis of four studies, found that someone’s natural level of muscle mass or their baseline level of muscle mass before they started lifting was not an influential predictor of their level of muscle growth from strength training. Specifically, starting levels of bone free, fat free mass, which for most intents and purposes is muscle mass, were only very, very weakly related to the gains in that fat free mass from resistance training. The correlations ranged from 0.1 to 0.2, which is a very, very weak. I would note that statistical power seemed to be low, which means that if there was a small effect, then this study wouldn’t have been able to pick up on it, but if we look at other studies on the relationship between how much muscle someone naturally has before they start lifting and how much muscle they gain from lifting, the relationships are also very weak and statistically non-significant in the majority of cases.

I remember I was very surprised when I first looked into this research for my PT course, but the research is actually quite clear at this point. There is minimal relationship in most research between how much muscle someone has before they start lifting and how much muscle they will gain. So if you have very little muscle mass before you start lifting, that does not mean that you are a hardgainer. Bone mass also did not predict the response to strength training. Some previous research has found that frame size did in fact predict the response to strength training, but it seems that someone’s frame size, which is like how broad shouldered you are and how big your general structure is, seems to influence your final muscular potential much more than the rate at which you can get there.

If you want to learn what your maximum muscular potential is based on the totality of evidence, I have created a calculator for you on my website. The link is in the description. And you will also get a two week free trial for my app. My app creates fully optimized training and nutrition programs for you based on your goals and preferences. Furthermore, it keeps these programs updated over time and implements progressive overload and advanced periodization techniques like reactive deloads and daily undulating periodization based on your progression. Check it out and let me know what you think. And see you next time.