welcome to the house of hypertrophy what key facts do you need to know about the exercises required to optimize muscle hypertrophy yet another great study has been released that helps us out it has put the leg press up against the leg extension and the straight leg car phas against the bent leg car phase will also reveal how the findings of this study potentially relate to other muscles like the triceps and biceps let's Dive In 28 trained individuals were recruited one leg was assigned to train the leg press while the other trained the leg extension one
leg also trained straight leg C phases and the other bent leg car phases this study design is powerful as all 28 subjects trained all four exercises as the same subjects were in all conditions differences in genetics nutrition and outside lifestyle factors were controlled after all your left leg hopefully doesn't sleep more or eat more protein than your right leg in each session these were the variables used weights were adjusted within and across sessions to keep subjects reaching failure in the 8 to 12 rep range the researchers measured the growth of two of the quadriceps heads
the rectus femoris and vastus lateralis summed across three regions it was found the rectus foror grew better with the leg extension while the vastest lateralis grew better with the leg press as for the calves growth of the lateral gastrus medial gastrus and Solus was measured each at one region medial gastrus growth was clearly greater for the straight leg Rays lateral gastrus growth also favored the straight leg although not quite as clearly contrastingly Solus growth favored the bent leg but the benefit was not super compelling and some may just regard this as similar hypertrophy there are
two key principles that help us to understand the findings of this study and these principles likely apply to other muscles such as the hamstrings triceps and potentially even biceps the first principle is that biarticular muscles experience suboptimal hypertrophy when one of their functions opposes what happens in a compound exercise the second principle actually tells us how we might be able to maximize the growth of B articular muscles it suggests positioning one of the two joints it crosses to place it at a longer length seems to produce more hypertrophy your head may be spinning in complete
confusion but it's simpler than it sounds let's break it down principle one likely explains why the rectus moror suboptimally Grew From the leg press and required the leg extension forget about the details of principle one for now and understand that all four quadricep heads cross over the knee in a way that means they all contribute to knee extension however the rectus morus also crosses over the hip in a way that means it contributes the hip flexion since the rectus sorus crosses Two Joints we say it's B articular the other three quadriceps heads can be described
as mono articular since they only cross the knee joints now during any compound exercise that trains the quads well such as a leg press and squat we need to extend our knees and extend our hips to lift the weight but although the rectus for moris is involved in the extension we just saw it's also involved in hip flexion the opposite of hip extension so a strong contraction of it would partly pull us down making it logical that the nervous system would minimize rectus thorus involvement thus all of these compound exercises likely suboptimally grow the rectum
amorus this is principle one a biarticular muscle such as the Reus sorus experiences suboptimal hypertrophy when one of its functions opposes what happens in a compound exercise such as the hip flexion from the rectus phorus opposing the hip extension from these compound exercises as a result isolated knee extension training is more effective for rectus fous growth principle one likely extends to the other main key biarticulate muscles in the human body I'll briefly detail how this applies to the triceps and biceps but feel free to check out the pinned comment for details on the hamstrings and
gastr nemus the triceps consist of three heads all cross over the elbow joint in a way that means they extend the elbow but the long triceps Head is by articular because it also crosses the shoulder joint in a way that means it's involved in shoulder extension and shoulder adduction during any compound pushing exercise such as the bench press and overhead press we extend the elbow but these movements also involve shoulder flexion and or shoulder abduction which are the opposing shoulder motions the L head contributes to if you're struggling to see how shoulder flexion or abduction
happens in these movements just focus on the upper arm anyhow a strong long head contraction would partly fight against us lifting the weight so it makes sense it's not highly involved indeed we have direct data demonstrating that pushing exercises such as the bench press suboptimally grows the long head of the triceps but does a better job at growing the lateral and medial heads isolated elbow extension excises have been documented to be very effective for growing the L head although certain compound exercises such as this pullover extension hybrid likely trains the lad effectively since this involves
combined l elbow extension and shoulder extension which both are L head functions but right now we don't have direct data on how effective these are and I'm skeptical they are superior to isolation elbow extension as for the biceps this one is quite controversial and you'll see why the biceps consist of the long and short head both cross the elbow joint and everyone knows they are involved in elbow flexion but both also cross the shoulder joint in a way that means they can contract during shoulder flexion and shoulder Abduction the biceps can also perform what we
call superation at the forearm and there's also evidence that biceps activity is higher when we're elbow flexing with a supinated grip anyhow during any compound pulling exercise such as rows pull-ups and chinups elbow flexion occurs but shoulder extension and or shoulder adduction also occur which are the opposite movements the biceps have at the shoulder once again if you can't see how shoulder extension or adduction happens in these movements focus on the upper arm indeed we have direct evidence dumbbell Rose even with a sulated grip produced much lower elbow Flex ey pery than dumbell Co the
reason I said this is controversial is that many people suggest chinups are one of the best biceps exercises the popular mik men even suggested this and it just so happens to be true audience the close grip Palms up pull down is the best bicep exercise in the world how could this be possible well those who believe the biceps are trained effectively with compound pulling exercises would say what we've detailed is wrong for at least three reasons firstly they may say although the biceps do cross the shoulder joint there's research suggesting their involvement in shoulder the
motion is minimal meaning your nervous system can effectively activate the biceps during these exercises secondly they might also reference this study that fascinatingly found pronated grip laap pull Downs produced similar elbow Flex of growth to barbell Coes finally some electromyographic research also finds High biceps activity during pull-ups and chinups and so many people feel their biceps are highly involved I actually believe these three arguments are pretty good but there are some solid counter points firstly although the biceps involvement in shoulder motion is indeed little it's still partially shortening in these movements which may mean it
nonetheless fails to optimally contribute to pulling exercises secondly as for the study finding similar growth between pull downs and curs this was elbow flexor growth which in this case consists of of both the biceps and brachialis the brachialis is a muscle under the biceps it's just a monoarticular muscle involved in elbow flexion due to this muscle being in the measurement we can't be certain biceps growth was truly similar between both exercises moreover to be completely transparent the author of this particular study has been involved in multiple studies with statistical anomalies so some might question the
study's validity finally the electrom myographic data is interesting but as detailed at the house of hypertrophy previously there are cases where electrom myographic data can probably be useful and other cases where it's not here it might not be useful for example we've seen the triceps lad minimally grows from compounds pushing exercises but some electromyographic research finds High triceps lad activity during the bench press so this is misleading in this circumstance as for people people reporting they feel their biceps highly with some pulling compound exercises someone might say you're actually feeling the brachialis not the biceps
so who's right it would be interesting to hear what you think on this matter so feel free to drop a comment below to truly get an answer I would love to see a study directly comparing chin-ups to a normal biceps curl until then I'm on the fence as to whether principle one applies to the biceps I know I know it's for strating that I remain on the fence but if it's any consolation my hypothesis would be that all compound pulling exercises are not optimal for biceps hypertrophy if it's not for principle one I think it
would be because the back musculature is typically the limiting factor in pulling exercises so your biceps may fail to reach maximal activation and tension so I think it comes as no surprised that to maximize biceps hypertrophy direct isolation biceps training is recommended Ed let us now move forward to principle 2 which tells us how we could maximize the growth of biarticular muscles principle 2 suggests positioning one of the two joints a b articular muscle crosses to place it at a longer length appears to produce greater muscle hypertrophy we'll understand what this exactly mean soon but
this principle likely explains why the gastr nemus grew better with straight leg C raises versus bentle C raises actually we have another study published in December 2023 which had untrained individuals train bent leg Cal raises with one leg and standing straight leg Cal raises with their other leg using these variables both lateral and medial gastonia's volume increases were better with the straight leg C raises while Solus growth was fairly similar between both exercises so comparable to the new study it generally shows better gastrous growth with straight leg raises and uncompelling evidence the Solus grows much
better with bent leg raises okay all three calf muscles the lateral gastrus medial gastrus and Solus cross over the ankle in a way that means they perform calf raising however the lateral and medial heads are B Artic as they also cross the knee joints this means they can shorten and contribute to knee flexion as the knees are flexed in a bent like C phase both gastr nmia heads are already shortened which likely compromises their Force generation this connects to the idea of active insufficiency which refers to when a biarticular muscle is shortened at both of
the joints it crosses which limits Force strictly speaking some mono articular muscles could experience meaningfully impaired Force at Short lengths but this is a discussion for another day and we'll stick to this notion of active insufficiency see today with the bentle calf raise all the calf muscles are shortened at the top of the calf raise but since we started with the knees already bent the gastr nemas are excessively shortened extending our knees will lengthen the gastrus so straight leg C raises train the gastrus at longer lengths which avoids active insufficiency this is principle two positioning
one of the two joints a biotic muscle cross es to place it at a longer length such as how positioning the knee in a straight position lengthens the gash nemus seems to result in more muscle hypertrophy if you've been following the house of hypertrophy for a while you'll know growing evidence suggests training muscles at longer lengths builds more muscle we've seen it with research suggesting that shortened range of motions fail to grow as much muscle at some regions to a range of motion that reaches longer lengths and we're also seeing it with selecting exercises that
have biarticular muscles at longer lengths which is what we're focusing on here across the web opinions conflict about the mechanisms behind training muscles at longer lengths but in my view avoiding active insufficiency is one potential mechanism behind wi trting muscles at longer length can be beneficial in some cases but other mechanisms are almost certainly in play too regardless of the mechanisms we've seen principle 2 with the hamstrings in the same way that straightening the knee can lengthen the gasto nemus the hamstrings can be lengthened by hip flexion seated leg Coes involve the hips flexed while
lying leg Coes do not indeed overall hamstrings hypertrophy was found to be superior with seated leg Coes in another paper so I would certainly recommend seated leg Coes overlying leg Coes we've seen it with a rectus sorus the new study analyzed in this video used normal leg extension but leaning back on the leg extension will lengthen the rectus sorus more and we saw in a recent video this produced greater rectos sorus hypertrophy than normal leg extensions feel free to check out that video for the full details of the study and possible alternatives to leaning back
leg extensions we've seen it with the triceps the triceps L head can be lengthened with shoulder flexion overhead extensions involve the shoulders flexed while push Downs do not L head hypertrophy has been documented mented to be superior with overhead extensions in another paper interestingly combined medial and lateral head hypertrophy was also greater with the overhead extensions an unexpected finding now many people do like pushdowns so I wouldn't completely ditch it if you don't want to but I would at least recommend a triceps exercise with the shoulders at a more flexed position to cover your bases
as for the biceps I know there are a few studies currently in the works on them I'm excited to see what they end up finding and we'll of course update you whenever they're [Music] released we've seen that principle one likely explains why the rectus florus grow suboptimally from the leg press and principle 2 likely explains why the gastr nemia's heads tended to grow better with the straight legar razes but why was vastest lateralis growth better with the leg press and why was Solus growth not drastically different between between straight and bent leg Rises with the
Solus some might speculate as Gast nemus involvement is reduced with bent leg raises the solier should increase its involvement and thus grow more this certainly sounds logical but according to the results we've seen it just doesn't seem to happen at least not significantly therefore straight leg cough raises might be all you need although bent leg raises could be useful for isolating the Solus if you'd like to do that as for the vastest lateralis you might speculate since the rectus moris is suboptimally involved in all compound exercises the other quad heads like the vastest lateralis must
increase their involvement and thus grow more but this is similar to the solest argument we just proposed which doesn't appear to significantly occur though of course things could differ between muscle groups although another possible explanation is most compound exercises like leg presses tend to involve more knee flexion than normal leg extensions this will effectively train and stimulate the vastest muscles at longer lengths which could explain the greater growth nevertheless to maximize overall quadriceps hypertrophy it seems a solid recommendation is to have both an isolated knee extension exercise for optimal rectus femoris growth and a quad
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