YT YouTube2Text

YouTube2Text → Transcripts → Was long length training BS all along? This changes everything.

Was long length training BS all along? This changes everything. — Transcript

by Menno Henselmans · 3,137 words · 314 segments · language en · Watch on YouTube

Open in transcriber Summarize with AI Download SRT/VTT

Full transcript

0:00The reputation of long length training
0:01and lengthened partials has been a bit like that of Britney Spears.
0:05A meteoric rise to popularity followed by a bit of a crash and a burn,
0:09but now perhaps a comeback.
0:12Up until a few years ago, full range of motion training was the gold
0:16standard, something that all evidence based fitness professionals agreed on.
0:20However, a few studies
0:21then showed that lengthened partials, doing partial repetitions
0:24specifically in the part of the movement where the muscle is lengthened,
0:28more stretched,
0:28actually result in more muscle growth even than full range of motion training.
0:32And of course, this got picked up by all
0:34the evidence based YouTubers like Jeff Nippard, Mike Israetel, and in particular
0:38Milo Wolf leading the charge and going all in on lengthened partials.
0:42The hype
0:42train crashed when multiple studies in trained
0:45individuals failed to replicate the findings from untrained
0:48individuals that lengthened partials beat full range of motion.
0:51The main critique, voiced by the likes of Paul Carter and Chris Beardsley
0:55was that lengthened partials and long length training
0:57are only beneficial to increase muscle length.
1:00This works in untrained individuals because they can actually still get longer
1:03muscle lengths,
1:04and this can result in the illusion, if you will, of larger muscles.
1:08The idea was that long length training results in sarcomerogenesis
1:12in series rather than in parallel.
1:14Basically, the muscle just gets longer, and since a muscle fascicle
1:18can only get so long because it's bound between two bones, that growth is finite.
1:23You can make a muscles total volume larger by lengthening it,
1:26but only a little bit.
1:27So in untrained individuals this could work.
1:29But in trained individuals the idea was, well,
1:31they already got those benefits from training with full range of motion,
1:35therefore we no longer see the benefits.
1:37However, an alternative explanation is simply
1:39that trained individuals grow less muscle in any study because in eight
1:43weeks, trained individuals are not going to gain a lot of muscle to begin with,
1:46so it's just harder to demonstrate any effect in general in trained
1:50individuals versus untrained individuals.
1:53So is long length training the muscle messiah, or is it just an overrated
1:56fad that we won't hear from anymore in a couple of years?
1:59I know many of you are sick about hearing about lengthened partials
2:02and long length training as you are about AI.
2:05However, three new studies fundamentally changed the narrative.
2:08The first study, for the first time shows compelling
2:11evidence of superior muscle growth with lengthened partials
2:14than with full range of motion in resistance trained individuals.
2:18The study, still in preprint, had a group of strength
2:21trained men complete a lower body training program with either full range
2:25of motion or lengthened partials, doing only the bottom part of the movement.
2:29The training program
2:30consisted of leg presses, leg extensions and lying leg curls.
2:34After eight weeks there were significantly more growth
2:36in the semitendinosus of the hamstrings in the group doing lengthened partials,
2:41and this was measured using gold standard magnetic resonance imaging, MRI.
2:45Total hamstrings growth was also larger in the group doing lengthened partials,
2:49but the difference wasn't, strictly speaking, statistically significant,
2:53with a p value just short of the .05 at 0.058.
2:58So kudos to the researchers for not doing p hacking there,
3:01because I think many researchers would have done that.
3:03This finding is extremely difficult to reconcile with the idea
3:06that lengthened partials just cause muscle lengthening.
3:09Trained individuals are very unlikely to still experience
3:12an increase in hamstrings length from doing lying leg curls.
3:15It's not exactly an exercise that stretches the crap out of the hamstrings.
3:19However, the study also doesn't support going all in on lengthened partials
3:23because there were no significant differences
3:25in muscle growth for any other muscle group
3:27than the hamstrings. For the quadriceps anabolic signaling and biopsy data
3:32both also fail to confirm any advantage of lengthened partials over
3:36full range of motion training.
3:37You could argue that the hamstrings difference was just a fluke.
3:40However, with MRI, in this type of study, I think that's not particularly likely,
3:46and a more likely explanation is that lengthened partials
3:49simply have a finite benefit. In the group only doing leg curls,
3:53if you're doing standard lying leg curls, you're not training the hamstrings at long
3:57lengths at all.
3:58Lengthened partials essentially are a way to
4:01still train hamstrings at somewhat longer muscle lengths.
4:04However, for the quads,
4:06they were doing leg presses and they were doing very deep leg presses.
4:10If you're already doing very deep leg presses, then doing lengthened partials
4:14on top of that is probably not as advantageous.
4:17So this would explain why the other muscle groups didn't benefit
4:21from the lengthened partials, or at least didn't
4:22clearly benefit in this particular study, while the hamstrings did.
4:26So what I teach in my online PT course and implement in my App
4:29is that you should have at least one good exercise that really targets a muscle well
4:33at long muscle lengths. However, you probably don't need to do long muscle
4:38length training for every single exercise with lengthened partials all the time.
4:42Moreover, the benefits of lengthened partials and long length training
4:45should logically depend on the length-tension relationship
4:48of the muscle and the resistance curve of the exercise that you're doing.
4:52Muscle grows from mechanical tension. Some muscle groups experience more active
4:56tension, and in particular
4:57also more passive tension at longer muscle lengths, but other muscle groups do not.
5:01If you venture into a range where you get clearly more mechanical tension,
5:05I think it's very likely that the longer length training in this particular context
5:08leads to more muscle growth.
5:10However, when you are venturing to a length where you sacrifice
5:14a lot of active muscle tension, then you might not get more muscle growth anymore.
5:17This would explain, for example, why one of our own earlier studies found
5:20that hip thrusts and squats result in equal muscle growth in the glutes.
5:24Hip thrusts should generate
5:26a lot more active tension, but squats have the advantage
5:29of training at longer muscle lengths and more passive tension.
5:31Presumably somewhere there
5:33there is a level of equivalence where you can get the same muscle growth
5:36either with more active tension or with more passive tension.
5:38And this is also what the researchers concluded in the second new study,
5:42although the way I read the results it actually makes a more compelling case
5:46for lengthened partials than the researchers say.
5:48The researchers had a group of non strength trained individuals complete
5:51a lower body training program in one of three ways.
5:55All of the groups did 3 to 4 sets at 8 to 10 repetitions.
5:59The full range of motion group did 0 to 90 degrees of knee flexion at 80% of 1RM
6:04at that range of motion,
6:05so the 1RM was tailored to the specific motion that they were doing,
6:09which is good because some studies they forget to do this,
6:11the shortened partials group, they did 0 to 50 degrees,
6:15so shortened partials, about half the range of motion,
6:17only the contracted part of the movement, also at an 80% intensity,
6:21think partial squats the way many people do them,
6:23and then the lengthened partials group did a 40 to 90 degrees,
6:26so basically like the bottom
6:28half of the movement, although this isn't technically real super
6:32long length training still, but they did it at a 55% intensity.
6:36So that's partial reps
6:37in a stretched position, but with substantially less weight.
6:41The substantially lower weight
6:42was chosen to equate the total amount of mechanical tension.
6:46So you have with a heavyweight full range of motion
6:49or shortened partials, or a lighter weight lengthened partials.
6:53The idea being that at this lighter weight the total amount of tension in the quads
6:58was going to be equivalent in the shortened partials
7:01and the lengthened partials group. In the full range of motion group
7:04it should still be higher, more mechanical tension.
7:07So this study essentially answers the question do lengthen partials still
7:10beat a shortened partials when we equate for total mechanical tension?
7:14One previous study on this found that the difference disappears
7:17when we equate for total tension, as you would expect.
7:19Tension is the main mechanism of muscle growth, so the benefits of lengtened
7:23partials should be mediated by mechanical tension.
7:26This is however, not what they found.
7:28After eight weeks, the lengthened partials resulted in significantly more growth
7:32than the shortened partials,
7:33even with the lower weights, and this was significant
7:36at two out of three of the locations they measured.
7:38Moreover, the lengthened partials, despite being at a lower weight
7:42and having a lower estimated total amount of mechanical tension on the quads,
7:45rivaled full range of motion training. They had similar muscle growth.
7:49The researchers concluded that since active forces
7:52were equated between the lengthened and shortened partials group,
7:55the extra muscle growth must have come from passive mechanical tension.
7:59However, this is not in line with how they measured total tension
8:03because the researchers measured total quadriceps tendon force.
8:07Total force logically includes both active and passive force,
8:11which means that all forms of mechanical tension contribute in the measurement.
8:14Technically, they measured quadriceps torque
8:17corrected for hamstrings coactivation divided by the patellar tendon moment arm.
8:20So it's basically an estimate of total forces, not just active forces.
8:25If we take these results at face value,
8:27it would mean that there is an additional mechanism
8:29beyond mechanical tension that drives the benefits of long length training.
8:33This would be an absolute game changer,
8:35not just for long length training and lengthened partials,
8:38but for our entire understanding of how muscle grows.
8:41Because we don't have any established mechanism
8:44other than mechanical tension as to what drives muscle growth.
8:48Such a complete paradigm shift generally shouldn't happen based on just one study,
8:52and there are indeed three big caveats to keep in mind here.
8:57The first major caveat is that total tendon force is not
9:00an unreasonable measurement for total muscle force,
9:03but it is not the same as specifically the amount of tension that's going on
9:07in the vastus lateralis, where muscle growth was actually measured.
9:11Moreover, these are estimates, and during a dynamic contraction
9:15where pennation angle changes and the muscle changes shape,
9:18these estimates are known to be somewhat inaccurate.
9:21Related to this, it's unknown how close to failure exactly the groups trained.
9:25They did a given number of reps with a given weight, and the idea
9:30was that this equatee tension,
9:31but they did note that some of the subjects in the lengthened
9:34partials group noted that the movement was harder than expected, so
9:38maybe they were actually simply training harder than estimated, and tension was
9:42actually higher in this group.
9:43And third, if we go back to the original critique
9:46that most of the muscle grow from lengthened partials might just be lengthening
9:49of the muscle rather than thickening, which is very finite in duration,
9:53these were untrained individuals,
9:54and the researchers measured that muscle fascicle length actually increased.
9:58So in this case, it could be the case that much of the additional growth
10:01was indeed just lengthening.
10:03And it might not apply to trained individuals like in the previous studies.
10:06The final and strongest argument against long length maxing is that most
10:10research doesn't support that longer lengths are always better.
10:13Which brings us to the third new study
10:15I have for you today on how to optimize your biceps curls.
10:18Bicep curls are an exercise
10:19where research has looked a lot
10:21into different muscle lengths, and generally it finds that longer
10:25lengths indeed have a benefit compared to shorter lengths.
10:28But there is a clear limit.
10:30The researchers had a group of untrained individuals train their biceps
10:33with Bayesian curls - cable curls looking away from the cable tower.
10:36One group did them the way I originally coined the exercise,
10:39which is with the elbow at the site.
10:41The other group let their elbow get dragged
10:43all the way back to get even longer muscle lengths.
10:46After ten weeks, there was no meaningful difference
10:48in muscle growth between the arms.
10:49It was 6 to 9% in both of the arms, as measured
10:53by ultrasound in the top and bottom parts of the elbow flexors.
10:56Bayesian analysis further supported that there was indeed no difference.
11:00This finding makes sense in light of the length-tension relationship of the biceps.
11:05I originally recommended Bayesian curls over
11:06dumbbell or barbell curls because with a dumbbell or a barbell
11:09there is no resistance in the bottom part of the movement.
11:12Gravity is only pulling straight down, so it's only as you start
11:15flexing the arm that you actually get some resistance.
11:17This is very detrimental for the biceps in particular,
11:20because the biceps actually produces the most active and passive force
11:24when the elbow is at your side, roughly in anatomical position.
11:27When you stretch the biceps beyond this point and get the elbow
11:30behind the body, you actually decrease the amount of active tension.
11:34And this is probably not entirely offset by the increase in passive tension.
11:39It's not just a case of getting the muscle
11:40to a longer length and thereby getting more growth.
11:43You also need to get high tension at that long muscle length.
11:46Often, when you let your arm get dragged back during a Bayesian curl,
11:49you lose some of the tension at longer lengths.
11:52All these limitations and talk of potential mechanisms aside,
11:55the strongest argument I think right now for actual long length maxing is that
11:59in basically every single study we see benefits or neutral effects.
12:03There is no evidence of harm.
12:05However, I'm still not a proponent of actually just doing all exercises
12:10at long lengths and always doing lengthened partials for two main reasons.
12:14The first reason is that injury risk and fatigue
12:18both are known to be correlated to the joint angles that you train in.
12:22Fatigue is joint angle specific, and injury risk and damage
12:25are also highly specific to movements and joint angles.
12:29So if you load all of your training on one muscle length,
12:33so the longer muscle lengths and you do partial range of motion all the time, then
12:36you’re loading all of that volume on one vector, and I think your total volume tolerance
12:40might be a lot lower.
12:41The second reason not to go all in on lengthened partials
12:44is that tracking your progress becomes very difficult.
12:47I think tracking your progress is extremely underrated,
12:49because if you don't know
12:50if your program is working, you don't know how to update it.
12:53There's so much talk about program optimization,
12:55and very few people talk about how to sustain progress on a program.
12:59If you don't know if you're progressing
13:00and with lengthened partials, you often won't,
13:02you don't know how to update your program because it's super difficult to know
13:06with a lengthened partial if you're just sacrificing range of motion,
13:09or if you actually got stronger. With a leg extension,
13:12a decent rule of thumb is that if you are leg gets horizontal,
13:15you can see that pretty well, and you have an idea of how you're progressing.
13:18This is even more easily the case with a chin up or a bench press,
13:21or a squat, where you get the weight up or you don't. With a lengthened partial,
13:25however, if you're getting the weight halfway up,
13:27how do you know if this time you weren't just short cutting the range of motion
13:31just a little bit
13:31to get that one extra rep. Your progress becomes a slippery slope.
13:35In my online PT course, I evaluated all the practical
13:38and theoretical evidence, and I came to the following guidelines,
13:41which are also largely what I implement in my App.
13:43First, it's almost certainly a good idea to have at least one exercise
13:47for every muscle group that trains that muscle at a long muscle lengths.
13:51Most people don't do this.
13:52Many people in the gym, they train with partial range of motion.
13:55They don't even use full range of motion, let alone lengthened partials,
13:57and they don't have exercises that train a lot of muscle groups
14:01at long muscle lengths, so they're probably leaving significant gains on the table.
14:04Big, big picture.
14:06One of the main findings of the whole lengthened
14:08partials and long length training movement
14:10is that we know why full range of motion training is beneficial over
14:14shortened range of motion training.
14:15The reason is that it's the longer muscle lengths that are driving
14:18the benefit, not so much the extra range of motion per se.
14:21It's about reaching longer muscle lengths,
14:23not about just maximizing joint range of motion.
14:26Second, I like doing lengthened partials in the last set of an exercise
14:29or the last sets of an exercise, and then leaving the first set
14:32with full range of motion so that you can still accurately benchmark
14:35your progression. And finally training at longer
14:37muscle lengths is most likely specifically beneficial when it actually increases
14:41total muscle forces, thereby mechanical tension.
14:44This includes active and passive tension. As a practical rule of thumb, exercises
14:49where you can do significantly more reps
14:51when you shortcut the range of motion benefit the most from lengthened partials.
14:55Think, for example, leg extensions, lying leg curls, or calf raises.
14:58And these are indeed exactly the muscle groups and the exercises
15:01for which we have compelling evidence that they do get more from lengthened
15:05partials than even full range of motion training.
15:08The fact that you can use substantially more weight
15:10or do substantially more reps with lengthened partials for these exercises,
15:13is basically an indication that you are leaving tension on the table.
15:18Exercises like calf raises benefit from lengthened partials,
15:21because the bottom
15:22part of the range of motion has a much higher active and passive forces.
15:26If you force yourself to go all the way up to lockout,
15:28while good for progress tracking, you do limit yourself
15:31in terms of the total mechanical tension that can be produced
15:34because you're limited by the very top part of the movement.
15:37While there's a large bottom part of the movement that could do a lot more.
15:40I hope this video helps you design more effective
15:42training programs and get more out of your training.
15:45If you like this type of evidence based fitness content,
15:47you'll probably also like this video and you'll probably love my online PT course.
15:52It is the most comprehensive course on the market by far
15:55that teaches you how to take your physique to the next level.
15:58Check it out!

About this transcript

This page contains the full transcript of Was long length training BS all along? This changes everything. by Menno Henselmans, generated from the public captions YouTube serves with the video. The transcript has 3,137 words across 314 segments, with the original timestamps preserved so you can click any line to jump to that moment in the embedded player.

What you can do with it

Use the transcript to take notes, quote the speaker, build a study guide, generate a summary with ChatGPT or Claude via the YouTube Summary tool, or export it as a timed subtitle file with YouTube to SRT. You can also re-open it in the transcriber to translate the transcript into 100+ languages.

Free YouTube transcript tool

YouTube2Text is a free YouTube transcript generator — no signup, no daily limit. Paste any YouTube link and get the full transcript instantly, with timestamps, click-to-jump, translation to 100+ languages, AI prompts for ChatGPT, Claude, and Gemini, and exports to TXT, SRT, VTT, or Markdown.