welcome to the house of hypertrophy what are the most effective and efficient exercises to maximize quadriceps hypertrophy the findings of a brand new study have some potentially important details it has compared two different leg extension variations some of you may be thinking why leg extensions aren't squats and leg press variations the best way to grow the quads as we'll see later these exercises absolutely can grow the quads well but they aren't enough because they fail to meaningfully grow a certain head of the Quad leg extensions on the other hand have been documented to grow all
four heads of the quads well especially the region that squats and leg presses minimally grow we'll also mention some underappreciated alternative two leg extensions if you can't train [Music] them 22 untrained men were recruited with one leg subjects trained the typical leg extension the hips were flexed at 90° and they moved the knee joint from one 110 to 0° with the other leg they train the leg extension with a Hip Flex to 40° with a knee joint also moving from 110 to 0° so the only difference was this variation has us leaning back the subjects
trained both exercises with these variables whenever subjects reach 20 reps on the first set load was increased to keep them in the 15 to 20 rep range the fact each subject trained with both exercises was great since this means the same subjects were in both conditions therefore differences in genetics nutrition and outside lifestyle factors likely won't confound the study the quadriceps consist of four heads and the researchers measured both rectus femoris and vastus lateralis growth each at an upper and lower region the result rectus fous growth at both regions was 1.4 to 2.7 times greater
with a 40° Hip Flex leg extension how on Earth is this possible the rectus femoris is what we call two-joint muscle it crosses both the hip and knee joints so besides contributing to knee extension it also contributes to hip flexion consequently with a leg extension leaning back allows us to lengthen the rectus femoris more that is it's in a relatively more stretched position this is important as mentioned previously at the house of hypertrophy training muscles at longer length seems to build more muscle and this new study adds to this body of literature with a rectus
growing better with a leg extension variation that positions it at a longer length the other three quad heads are one joint since they just cross the knee so all contribute to just knee extension so provided we're moving the knee joint through the same range of motion which was done in this study we'd expect these muscles to grow similarly between both variations as they're moving through the same muscle lengths indeed vastest lateralis growth at both regions was fairly similar between the two leg extension variations there are at least three questions you might have the subjects were
previously untrained what about trained people what about laying down to 0 de of hip flexion and what about alternatives to leaning back leg extensions a paper from Japan published last year potentially answers the first two questions nine bodybuilders were recruited they performed the leg extension with 0 40 and 80° of hip flexion during each muscle activation was indirectly measured with MRI both the zero and 40° hip flexion leg extensions produced higher upper and middle rectosis activity than the 80° variation lower rectos morus activity did not statistically differ between them but we still see the values
tended to be higher with a z and 40 degree variations therefore this study suggests trained individuals might also benefit from leaning back leg extensions but there doesn't seem to be a greater benefit for 0° compared to 40° of hip flexion if anything the raw numbers favor the 40° variation however I will note that although this muscle activation measurement has been associated with actual muscle growth in previous analyses the context of these papers are important none of these papers verified that this muscle activation measurement successfully predicted muscle growth when comparing exercises at different muscle lengths and
I think it's possible this measurement fails to fully account for Passive forces that occur when a muscle is at longer lengths I say this to say it's possible these results underestimate the muscle growth potential of 0 degree hip flexion leg extensions thus hopefully we get research comparing the 0 to 40° variations for now we can at least say it's likely both zero and 40° hip flexion leg extensions are better than a traditional variation for overall rectus sorous development but what if you can't perform leaning back leg extensions the reverse Nordic curl and squat are both
potentially great Alternatives both are performed with virtually no hip flexion just like the0 degree hip flexion leg extension but unlike the Z degree hip flexion leg extension both of the exercises allow us to bend our knees to an even greater degree of flexion so in addition to lengthening the rectus furus even more all other three quad heads are going to be trained at even longer muscle lengths than what we achieve with leg extensions does this mean these two exercises can grow these three quad head even more than any leg extension variation maybe but it is
also possible that there's a threshold to the amount of muscle lengthening that's beneficial for growth such that these two exercises don't build the three quad heads more than any leg extension variation there are also some other subtle differences between these exercises hopefully future research Compares them to tease out any potential differences in growth for now at least I believe we can hypothesize both of these are going to be excellent alternatives for growing the quads particularly the rectus femoris depending on your current level these two exercises may be too hard or easy to perform but I've
mentioned some training and progression tips in the pinned comment if you're interested this discussion so far has been centered around maximizing muscle hypertrophy but I will say if you just rather train with normal leg extensions that is perfectly fine at the end of the day although it may not be the biggest bang for your buck it still will build mus [Music] musle the exercises mentioned so far largely involved to isolated knee extension but the quads are commonly trained with combined knee and hip extension exercises we have multiple studies suggesting all of these exercises likely minimally
grow the rectus phorus but develop the other vastest muscles well the lack of rectos moros growth from these exercises can likely be explained by the simple fact that rectos morus is a joint muscle during the bottom position of any combined knee and hip extension exercise we need to produce both knee extension and hip extension but since the rectus sorus is involved in hip flexion the opposite of hip extension a strong contraction would fight against us trying to get up the other vastus muscles are just involved in the extension so are free to highly contribute to
the extension in these exercises so it makes sense these grow well from these exercises some of you may be Be Wondering the leg extension also still grows the vastest muscles how does this growth compare to that achieved from combined knee and hip extension exercises most of the electromyographic analyses I found comparing leg extensions to squats lunges or leg presses showed that the latter exercises elicited higher activity of the various vastus muscles now as mentioned at the house of hypertree previously electromyographic Studies have limitations but as described by researcher Brad shanfeld there seems to be an
upcoming study finding When comparing leg extensions to leg presses leg presses grew the vastest lateralis better and that the leg extension Target direct as for moris which is the mid mid quad muscle MUSC that goes down the center of the quad and the vast lateralis one of those three vast muscles ler on the lateral aspect of the Quad was targeted to a greater extent with the leg press some degree of upper to lower Regional differences could exist this study compared Smith machine squat to leg extension training in trained subjects unsurprisingly the leg extensions grew the
rectus foror as more especially at the lower region as a note based on the data we've seen we can hypothesize if leaning back leg extensions were performed much better upper and middle rectus morus growth would have been seen vastest lateral growth at the upper and middle portions tended to be better with the Smith machine squats while growth at the lower portion fascinatingly favored the leg extensions I should note there were a couple of limitations with this study so I would like to see another study like this but in total the available evidence leans towards the
idea that growth of the vestus muscles at least in certain regions can be better with combined knee and hip extension exercises so to maximize overall quad growth having both an isolated knee extension and combined knee and hip extension exercise is probably a great idea we'll have future videos at the house of H pery exploring and comparing different squat leg press and lunge variations so stay tuned for that considering the conflicting information across the web things can get pretty confusing about how you may want to train I hope the videos at the house of I pery
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