Q&A: Loaded Stretching For Strength And Hypertrophy

Question: Can I gain strength and size faster by performing loaded stretches between exercises?

Answer: Research on the effect of static stretching (without weight) between sets on muscular strength and hypertrophy shows mixed results. A study by Wayne Westcott that compared the results of seventy two novice trainees doing high intensity training with and without a twenty second static stretch for the muscles worked found the group that stretched had twenty percent greater strength increases over a ten week period (1). Other studies show either no difference in strength between groups training with or without inter-set stretching (2) or that inter-set stretching reduces strength gains (3). This suggests there might be some benefit to inter-set stretching, but adding loaded stretching to your workouts isn’t going to cause you to suddenly start packing on “pounds of lean muscle” while “stripping off body fat at the same time” as some people are claiming.

There are plenty of impressive studies on the effect of loaded stretch on hypertrophy in animals, but I have yet to see this duplicated in humans. A lot of the recent marketing hype for inter-set stretching under load or “cell expansion protocol” is based on a study they claim shows it causes 200% faster muscular strength and size increases, but I have been unable to find this study anywhere anywhere, and when I asked the bodybuilder selling the program where the study was published his only reply was “University of Tampa”. I asked for a specific reference, but have yet to receive a response.

Where is the research on cell expansion protocol?

Where is the research on loaded stretch, AKA “cell expansion protocol”?

The only mention of the study I could find was in an obscure bodybuilding web site interview of Jacob Wilson, PhD who said the study involved a thirty-second loaded stretch immediately following  each set of a triple drop set of heel raises on a leg press, but gave no title, no reference, and no specifics on the results. The study is not listed on Dr. Wilsons CV, either. If I am able to find and read the study I will update this article with whatever information I find. It’s possible the study is still under review, but I’m not going to hold my breath. If a study actually showed a training technique could produce such a huge increase in muscular strength and size you would expect the authors and the people selling a program based on it to provide more details on it.

If you want to experiment with regular static or loaded stretching between exercises be very cautious with the degree of stretch. Only go until you feel a moderate stretch in the target muscles. You shouldn’t feel the stretch in your joints or feel any kind of pain. If you do, you’re going too far. Be very careful with your shoulders performing loaded stretching on exercises like pullovers and chest flys, and on any exercise where the stretch is done in the position of maximum moment arm, where the lever against the muscles is the largest.

Loaded stretching  is not going to “double your muscle gains” or cause “rapid fat loss”, as some internet marketers claim, but Westcott’s research suggests some form of inter-set stretching might be worth adding to your workouts. If you want to experiment with it do so cautiously, keep accurate records of your workouts and take measurements before you start and every couple of weeks after so you can determine the effect.

Update: Since posting this article only a few days ago I’ve received several e-mails from people who injured themselves in the past doing various types of loaded stretching, usually on exercises where the stretch was done in the position of maximum moment arm like pullovers and chest flys, but also with triceps extensions and heel raises on a leg press. Regular static stretching would be a safer option, but if you decide to experiment with loaded stretching please be careful.

Update 2: In a recent conversation Anthony Roberts informed me, “Jacob’s nickname among his colleagues and in the wider scientific/professional world is “King Midas” because everything he touches turns to gold (ie everything is proven to work when he is paid to study it, or his friends have a new product or idea). He did the work on HMB-FA that nobody believes”.

It’s pretty pathetic when a “scientist” like Wilson is falsifying research for profit. This is why it pays to be skeptical.

You can read Anthony’s expose’ on Wilson and the HMB study here.

References:

1. Best Of Both Worlds: Stretching and Strengthening, by Wayne Westcott, PhD

2. Souza, Antônio Claudio, Claudio Melibeu Bentes, Belmiro Freitas de Salles, et al. Influence of Inter-Set Stretching on Strength, Flexibility and Hormonal Adaptations. Journal of Human Kinetics, 36.1 (2013): 127-135. Retrieved 14 Jun. 2014, from doi:10.2478/hukin-2013-0013

3. Borges Bastos CL, Miranda H, Vale RG, Portal Mde N, Gomes MT, Novaes Jda S, Winchester JB. Chronic effect of static stretching on strength performance and basal serum IGF-1 levels. J Strength Cond Res. 2013 Sep;27(9):2465-72. doi: 10.1519/JSC.0b013e31828054b7.

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  • Bay Jun 14, 2014 @ 10:55

    What exactly is loaded stretching? Never heard of that term before.
    Thanks
    Bay

    • Drew Baye Jun 14, 2014 @ 11:37

      Bay,

      A loaded stretch is performed by holding a weight in the stretch position of an exercise. Keep in mind you can only achieve a true stretch for a few muscles, and even some of those can’t be stretched practically under load.

      For example, you can not stretch all four quadriceps muscles, only the rectus femoris since it is the only one that crosses the hip as well as the knee. This is why you only feel a stretch in the front of your thigh if you flex your knee with your hip extended, and not if you flex it with your hip flexed. A muscle can only lengthen so far, so if a bi-articulate muscle like the rectus femoris is already lengthened across one joint trying to lengthen it across the other stretches it.

      The standing quadriceps stretch only actually stretches the rectus femoris.

      There is no machine or barbell exercise that provides direct resistance to the quadriceps in this position, and if there was it would probably not be good for your knees. Even if loaded stretching is shown to provide a significant benefit it isn’t possible or practical for many muscle groups.

  • Al Coleman Jun 14, 2014 @ 11:19

    Interesting Drew. I wonder what exactly it is they mean by ‘loaded stretching’? I remember John Parillo promoting something similar in the early 90’s.

    • Drew Baye Jun 14, 2014 @ 11:44

      Al,

      They mean holding a weight in the stretched position of an exercise, similar to the fascia stretching Parillo was promoting.

  • Ed Jun 14, 2014 @ 13:32

    I watched the site with gritted teeth twice.I still have smoke coming out of my ears.The level of hype was truly amazing.Ben P spouted incredible nonsense on and on designed to appeal to the insecure adolescent and the generally immature pressing all the familiar magic word buttons one after the others,unlimited gains{in your fantasy world}women falling at your feet,become an Alpha male etc etc.I stated to wonder whether outakes for the hype would show him rolling around on the floor wqith laughter with what he was attempting to say.He is supposed to be an intelligent man so he must have actually known that what he was saying was nonsense.As a result of this I would conclude that conscious deception is involved and therefore it says something about his ethics without you ever meeting the man.Not that I think Pro Bodybuilding is exactly the most honest of fields anyway,so deception like this is merely an extension of its already lie ridden culture and at one piece with it.The actuall training program is supposed to be pretty hard and if it is that is likely to be the reason for the success of anyones before and after photos.Other than that i found it intellectually repellent,sad and cringe inducing.

    • Drew Baye Jun 14, 2014 @ 15:07

      Hey Ed,

      I’m sure the training program is effective for most people if done hard, progressively, and consistently, but no more than any other good program done hard, progressively, and consistently. Of course, that doesn’t sell as well as telling people you have the muscle-building “secrets” of pro bodybuilders and Hollywood stars.

  • verim Jun 14, 2014 @ 18:05

    There are 100s of techniques used in exercising, but also lot of unknown mechanism in human biology and there is no single way what works best for most of people. Interesting point for me is, that there are thousands of world famous exercise physiologists and coaches, but no one of them is using this kind of shameless marketing fraudulent “science” to sell something like this to naive average Joes. When I see on NSCA or ACSM that this is the best way to develop muscle, maybe than I shall believe, but it seems that B.Pa…and Mr West… have more knowledge than all of the worlds coaches and should receive a Nobel prize for biology? Probably not 🙂 This is my personal opinion. 100% agree with Drews comment.

    • Drew Baye Jun 15, 2014 @ 10:22

      Verim,

      You’re right, there are a huge variety of training methods that can all be effective if done hard, progressively, and consistently. There might be something to this, but until I see research showing it improves strength and hypertrophy significantly in humans I remain skeptical.

      As Carl Sagan was fond of saying, extraordinary claims require extraordinary evidence. If you’re telling people they can double their muscle gains and add several pounds of muscle every week while losing fat you better have something substantial to back it up.

  • Steven Jun 14, 2014 @ 20:17
    • Drew Baye Jun 15, 2014 @ 10:09

      Like I said, there are plenty of studies showing impressive results in animals, but I have yet to see any study showing practical methods of doing this make a significant difference for humans (I doubt most people are willing to have their joints immobilized to stretch a muscle and have an electrical current run through it).

      This doesn’t support the outrageous marketing claims of hucksters like DelMonte and Pakulski that stretching between exercises is going to make a significant difference in musclular strength and size gains.

  • Steven Jun 14, 2014 @ 20:22

    Didn’t Arnold do his fly’s with an emphasis on the loaded stretch ?

    • Drew Baye Jun 15, 2014 @ 10:01

      Hey Steven,

      I think he did. There might be some benefit to this for some exercises if you are cautious with the degree of stretch, but, I have yet to see any human studies using practical methods of doing this which have shown a significant benefit.

      • Steven Jun 15, 2014 @ 16:46

        Thanks for the insight Drew. I will try to find some human studies, but I do incorporate them in my training.

        • Drew Baye Jun 16, 2014 @ 11:17

          Steven,

          You’re welcome. As long as you’re conservative with the degree of stretch it probably doesn’t hurt, but it isn’t going to have the kind of impact on muscular strength and size gains that hucksters like Pakulski and DelMonte claim.

  • CJ Jun 14, 2014 @ 23:34

    Ha HA,
    I happened to be watching that ‘webinar’ but it was a whole lot longer than 4 minutes. Stretching in between sets and as part of warm up and cool down from training used to be just normal common sense approach to training. Now people are selling it for $100. Thanks for realty check Drew.

  • Scott Rhodes Jun 17, 2014 @ 15:02

    What about post workout stretching? I believe the study you mentioned by Westcott involved post workout stretching in middle age golfers (a group I am part of and familiar with 🙂

    • Drew Baye Jun 18, 2014 @ 14:38

      Hey Scott,

      I’m willing to consider the possibility there is some benefit, but it probably isn’t going to do much.

      • Slim934 Jun 19, 2014 @ 13:53

        What is your perspective on the use of a Foam Roller for post-workout purposes?

        • Drew Baye Jun 19, 2014 @ 14:05

          Slim,

          I think they’re a waste of time.

  • Chief Jun 18, 2014 @ 11:07

    Hi Drew!

    In my understanding, I’ve read many articles etc., stretching in general is overrated – or even utter bullshit. Is there any articles or studies (etc.) you could point out, and what is your opinion on stretching in general?

    • Drew Baye Jun 18, 2014 @ 14:36

      Hey Chief,

      With a few exceptions, I doubt there is much advantage to stretching in addition to a proper strength training program. I’m willing to consider the possibility it might provide some benefit, but I’d need to see better evidence to be able to recommend it. If you are trying to regain normal range of motion after immobilization due to injury stretching can help, and if you are attempting to achieve extremely high levels of flexibility for certain martial arts or dance it is necessary, although joint stability may suffer.

  • Chief Jun 18, 2014 @ 11:12

    Just to make clear, I challenged myself not to stretch for some time, and actually now almost 2 years has passed without stretching. I must say – with HIT workouts etc. – I feel better and move better.

  • Brian Jun 30, 2014 @ 16:51

    “Since posting this article only a few days ago I’ve received several e-mails from people who injured themselves in the past doing various types of loaded stretching ”

    DING! DING! DING! DING! I have seen this a lot! Personally, and this is just from my own experience, opinion and desire to protect clients, I never teach, recommend or allow clients to do loaded stretching during workouts.

    My logic is this – IF you are doing a HIT routine (and any other type of workout protocol) properly, you are compromised and in a weakened state and you can easily underestimate it’s effect on you. It only takes one single momentary lapse of focus or technique to deliver a life altering injury. Example – the macho idiot coming out of the bottom of a deep squat with a weight he cannot truly move and POP! there goes the ankle or knee.

    I want my clients to focus on HIT and then they can stretch afterward. Normally, I find them so exhausted after a proper HIT routine that they are very calm, which passively gets them to stretch safely and gently, almost meditatively.

    • Drew Baye Jun 30, 2014 @ 20:56

      Brian,

      With the feedback I’m getting from people I’m definitely recommending against loaded stretching. A static stretch for each muscle group after the exercise or after the workout would be a much safer option.

  • Wayne Jul 3, 2014 @ 13:40

    Hey Drew,

    What’s you recommendation for improving hip flexibility? Would proper HIT leg workouts help in that area? I am a 45 year old golfer, skateboarder and snowboarder. I sometimes feel like hip tightness affects my athleticism.

    Thanks,
    Wayne

    • Drew Baye Jul 4, 2014 @ 14:29

      Hey Wayne,

      Full-range squats or leg presses and stiff-leg deadlifts or trunk or hip extension will improve hip flexibility, but it may also help to perform static stretches after your workouts if you have below-average flexibility.

  • Simon Jan 2, 2019 @ 22:56

    The link to Anthony’s expose’ on Wilson and the HMB study is no longer valid. Here’s the Wayback Machine link to the article: https://web.archive.org/web/20150317170839/http://romanoroberts.com.mx/why-nobody-believes-the-latest-hmb-study/

    • Drew Baye Jan 3, 2019 @ 11:28

      Hey Simon, thanks for the heads up! I will fix that.