Hip Extension Torque: The Scientific Guide to the Posterior Chain

I have a little secret to share. Over the past six months, my colleague Chris Beardsley and I have been working on a huge project.

I can’t begin to estimate the number of hours that have been put into this project. I suppose it started 22 months ago when I arrived in New Zealand and began my extensive researching expedition. I didn’t have many friends out there, so I’d just stay in my office, downloading and categorizing one article after another. Some nights I wouldn’t go to sleep; I’d work overnight and my professor would arrive in the morning and chew me out for neglecting my health. But I wasn’t concerned – I was building the world’s greatest scientific library on the posterior chain.

Over the past 22 months, I amassed around 1,000 articles pertaining to glutes, hamstrings, and hip extension. It’s quite literally too much for any one person to handle. This is where Chris Beardsley comes in. I approached him six months ago and asked for his help. I sent him all the studies and left him alone for a while to assess the situation. What I did not realize at the time was that he is likely the most competent individual in the scientific fitness community. I remember my first phone call we shared on the subject – I gave him some instructions and guidelines, and somehow he ended up far exceeding my wildest expectations. Without Chris, this product would not have been possible. No way in hell. I’m just not that competent. Chris was able to create in real-life what I had envisioned in my mind but could not have completed by myself.

By combining our talents, Chris and I have pulled off what I believe to be the greatest scientific fitness product ever created. It’s centered on hip extension and the posterior chain, but it covers a huge array of topics.

It also covers research that I have yet to release to the public – things I’ve learned from collaborating with a top engineer across the world, from having discussions with top researchers, and from conducting various experiments. So there’s a lot of information in this eBook that cannot be found anywhere else in the world.

If you are interested in glutes, hamstrings, hip extension torque, torque curves, power, strength, force, hypertrophy, biomechanics, moment arms, muscle physiology, powerlifting, weightlifting, bodybuilding, squats, deadlifts, good mornings, kettlebell swings, hip thrusts, back extensions, sprinting, jumping, sled work, glute ham raises, etc., then you will absolutely love this eBook.

I’m not sure how many studies we referenced, but there are probably more than 200, and almost each page contains graphs, charts, figures, and links.

I wish there was a product out there like this fifteen years ago – if so it would have dramatically accelerated my knowledge and understanding of sports science.

Chris and I combined the practical knowledge we’ve learned as lifters and trainers with the scientific knowledge we’ve learned as sports scientists and biomechanists, and the result is something that I’m so proud of it’s hard to describe.

This is a product that you’ll want to read over and over again, sort of like a modern day Supertraining (Mel Siff).

My readers know that I’m a very honest man. I can guarantee that you will be incredibly impressed by this product. It’s unlike anything else I’ve ever seen (and I’ve seen it all).

The time Chris devoted toward creating the product, the hours I spent obtaining the literature, the hours Chris devoted to obtaining his own literature, the energy that went into planning, editing, and improvements, and the branding of the product – it all shines through.

If you are a serious lifter or athlete, a trainer or coach, a therapist or clinician, a sports science researcher or a professor, a fitness writer or blogger, then this is the product for you. If you study this diligently, you will be more knowledgeable about biomechanics than 99% of the fitness world.

While Strong Curves (comes out in April 2013) is a programming book that contains workouts and exercise descriptions, Hip Extension Torque is a scientific book that gives you biomechanical explanations and creative ways to enhance your understanding of the posterior chain.

In this eBook, Chris and I teach you all sorts of biomechanics topics. We teach you what torque is and what influences torque production. We teach you how to calculate the hip extension torque your posterior chain muscles create when you perform squats, deadlifts, good mornings, back extensions, and 45 degree hypers. We summarize all the available literature conducted on hip extension torque pertaining to functional, high-velocity, and high-force exercises. We even have portions devoted to pelvic tilt, the elderly, and basic hip extension activities such as gait and sit-to-stands for the physical therapists out there.

Basically, this eBook is almost 300 pages of pure awesomeness. It has my full stamp of approval! I will be referring to this product quite often over the next couple of years.

You can buy this product by clicking HERE. I’ve seen fitness experts sell things for hundreds of dollars that don’t contain a fraction of the content found in this eBook, and right now we’re offering it for only $49. The first 100 purchasers will receive a free one-hour group-conference call with me. Just throwin’ that out there.

For those interested in checking out the extended table-of-contents, here it is:

1. What is hip extension and hip extension range-of-motion?

  1. Why study hip extension range of motion?
  2. What are hip flexion and extension?
  3. What are hip flexion and extension ranges of motion?
  4. What factors affect hip extension range-of-motion?
  5. What is a normal hip extension range-of-motion?
  6. How does hip extension ROM change with hip abduction and knee flexion?
  7. How is hip joint flexibility different between males and females?
  8. How does hip extension ROM change with lower back pain?
  9. How does hip extension ROM change with increasing age?
  10. How does hip extension ROM change in development?
  11. How does hip extension ROM relate to the functional ability of older people?
  12. Does limited hip extension ROM lead to reduced hip extension strength?
  13. Does limited hip abduction ROM lead to reduced hip abduction strength?
  14. How can hip extension range-of-motion be increased?

2. What is pelvic tilt?

  1. Why study anterior and posterior pelvic tilt?
  2. What are anterior and posterior pelvic tilt?
  3. How do muscles create anterior and posterior pelvic tilt?
  4. Does muscle activity change with pelvic tilt?
  5. How does pelvic tilt change during sitting and standing?
  6. Does muscular balance during hip extension affect pelvic tilt?
  7. What is a normal pelvic tilt angle in men and women?
  8. Is anterior pelvic tilt correlated with lumbar lordosis?
  9. How does lumbar curvature change during a functional lifting task?
  10. How does restricting pelvic motion affect lower back training?
  11. Do the hip extensors decrease in activity with restricted pelvic motion?
  12. Can pelvic tilt angle change because of sporting activities?
  13. What is the normal tilting behavior of the pelvis during running?
  14. Does lumbar lordosis correlate with anterior pelvic tilt during running?
  15. How does hip extension ROM relate to anterior pelvic tilt during running?
  16. When are anterior and posterior pelvic tilt advisable during lifting?
  17. How can we control the degree of pelvic tilt using exercise?
  18. Which abdominal exercises are best for reducing anterior pelvic tilt?
  19. Which abdominal exercises do not also activate the hip flexors?
  20. How can we control the degree of pelvic tilt using exercise?

3. What is muscle architecture?

  1. Why study muscle architecture?
  2. What is muscle architecture?
  3. What is pennation angle?
  4. Why is pennation angle important?
  5. What causes the pennation angle to change?
  6. What is normalized fiber length?
  7. What causes normalized fiber length to change?
  8. What is physiological cross-sectional area?
  9. What is physiological cross-sectional area?
  10. Why is physiological cross-sectional area important?
  11. How are muscle architecture parameters related?

4. Which are the hip extensor muscles?

  1. Why study the hip extensors?
  2. What are the hip extensor muscles?
  3. How do the hip extensors stack up against the other hip muscles?
  4. What are the origins and insertions of the hip extensor muscles?
  5. Which are the biggest hip extensor muscles?
  6. What is the pennation angle of each of the hip extensors?
  7. What is the normalized fiber length of each of the hip extensors?
  8. What is the physiological cross-sectional area of each of the hip extensors?
  9. Why do the hamstrings have different architecture from each other?
  10. How does the muscle architecture of the hamstrings change with joint angle?
  11. How might the architecture of the hamstrings influence their risk of strains?
  12. What is the architecture of the different regions of the hamstrings?
  13. What is the architecture of the different regions of the adductor magnus?
  14. What is the architecture of the different regions of the gluteus maximus?

5. What is the length-tension relationship?

  1. Why study the length-tension relationship?
  2. How does the length of a muscle affect the force exerted?
  3. What is the active length-tension relationship?
  4. What is the passive length-tension relationship?
  5. How do the passive and active length-tension relationships integrate?
  6. How does the length-tension relationship apply to a two-joint muscle?

6. What is the force-velocity relationship?

  1. Why study the force-velocity relationship?
  2. How does the force exerted by a muscle change with contraction velocity?

7. What is hip extension torque?

  1. Why study hip extension torque?
  2. What is torque?
  3. Why talk about torque and not just force?
  4. How can we visualize torque?
  5. What is internal torque?
  6. What terminology is used for internal torque?
  7. What is hip extension torque?
  8. What is external torque?
  9. What terminology is used for external torque?
  10. What factors influence moment arm length?
  11. What are the moment arm lengths in the anatomical position?
  12. How do moment arms change with hip extension range of motion?
  13. What is the difference in moment arms between men and women?
  14. How can hypertrophy affect the length of muscle moment arms?
  15. What are perpendicular muscular forces?
  16. What factors influence the size of the perpendicular force?
  17. Which hip extensors have the most effective line of action?
  18. How does muscle architecture affect muscular force?
  19. Which muscles are activated best throughout hip extension ROM?
  20. How does the strength of the hip extensors change with muscle length?
  21. How does hip extension torque change with hip flexion?
  22. How does the torque of the hamstrings change with muscle length?
  23. How does hip extension torque change with contraction velocity?
  24. How does muscle fiber distribution affect muscular strength?
  25. How does muscle fiber distribution alter between muscles?

8. How does the degree of hip flexion affect the strength of the hip extensors?

  1. Why study where the hip extensors are strongest?
  2. How can we measure hip extension torque at different joint angles?
  3. How does isometric hip extension strength change with joint angle?
  4. How does isokinetic hip extension strength change with joint angle?
  5. Why is a comparison of internal and external torque curves helpful?

9. What effect does knee flexion have on hip extension exercises?

  1. Why study the impact of knee flexion?
  2. How does knee flexion alter the effect of a hip exercise?
  3. How does the degree of knee flexion alter the effect of an exercise?
  4. How does the torque of the hamstrings change with muscle length?
  5. How does the degree of knee flexion change muscle activity?
  6. How does the degree of knee flexion alter the effect of an exercise?

10. What effect does the direction of force have on hip extension exercises?

  1. Why study the impact of direction of force?
  2. What are the stretched and contracted positions?
  3. How do we specify direction of force?
  4. What directions of force are possible with hip extension?
  5. How does direction of force change the effect of an exercise?
  6. How can we compare similar exercises that have different directions of force?
  7. How does the direction of force affect the muscle activity?
  8. Why are the stretched or contracted positions important?
  9. Why do some exercises give you a pump in your glutes and hamstrings?
  10. Why do some exercises make your glutes and hamstrings sore?

11. How can we estimate torque for various movements?

  1. How can we calculate torque for various movements?
  2. How can we calculate torque for various exercises?
  3. How can we estimate torque in a deadlift?
  4. How can we estimate torque in a squat?
  5. How can we calculate torque in the good morning?
  6. How can we calculate torque in the reverse hyper?
  7. How can we calculate torque in the 45-degree back extension?
  8. How can we calculate torque in exercises in other positions?
  9. Why is it helpful to calculate hip extension torque at different ROMs?
  10. What is the hip extension torque during a glute-ham raise?

12. What is the hip extension torque during functional activities?

  1. Why study hip extension torque in functional activities?
  2. Which functional activities should we study?
  3. Is hip extension or hip flexion torque more important for walking?
  4. Is hip extension torque important for faster walking speeds?
  5. Is hip extension torque important for bone density?
  6. How is hip extension torque during sit-to-stand affected by load?
  7. Is hip extension torque in sit-to-stand affected by age?
  8. Is hip extension torque greater in sit-to-stand than in a free squat?
  9. Is hip extension torque during a sit-to-stand affected by chair height?
  10. Does foot placement affect hip extension torque during a sit-to-stand?
  11. Is hip extension torque during a sit-to-stand affected by obesity?
  12. How do hip and knee moments balance out during sit-to-stands?

13. What is the hip extension torque during high velocity activities?

  1. Why study hip extension torque in high-velocity activities?
  2. Which high velocity activities involve hip extension torque?
  3. Does hip extension torque correlate with vertical jumping performance?
  4. Do jumps in different directions require similar hip extension torques?
  5. How much hip extension torque do gymnastic drop landings produce?
  6. Do faster sprinting speeds require greater hip extension torques?
  7. How do accelerating sprints and maximum-speed sprints differ?
  8. Does hip extension torque increase with increasing side step distance?
  9. What is different about hex-bar jump squats?
  10. How much hip extension torque do the Olympic lifts require?
  11. How does hip extension torque change with load in the Olympic lifts?
  12. How can we maximize power outputs using the Olympic lifts?
  13. How can we maximize rate of force development using the Olympic lifts?
  14. Do the Olympic lifts improve athletic performance?
  15. How similar are the joint moments in jumping and jerking?
  16. What are the shear and compressive forces in the kettlebell swing?
  17. How do the kettlebell swing and jump squats compare?
  18. What are the ground reaction forces during the kettlebell swing?

14. What is the hip extension torque during high force exercises?

  1. Why study hip extension torque in high-force activities?
  2. Which high force activities involve hip extension torque?
  3. How are the good morning, back extension and 45O back extension different?
  4. Which requires greater hip extension torque: split squats or back squats?
  5. How does load position affect hip and knee moments in dumbbell squats?
  6. Which produces more power at the hip joint: front squats or back squats?
  7. How does hip extension torque during the lunge change with loading?
  8. Why might lunges make the quadriceps sorer than other exercises?
  9. Which type of lunge maximizes hip extension torque?
  10. Which type of step-up maximizes hip extension torque?
  11. How do depth and loading affect hip extension torque during the squat?
  12. How does technique affect hip extension torque in the squat?
  13. So should we prefer a hip-dominant squat?
  14. Does hip extension torque differ between legs in the squat?
  15. Does lifting speed affect hip extension torque in the squat?
  16. Does lifting speed affect hip extension torque in the squat?
  17. How can partial squats be used effectively in strength programs?
  18. Why might squats make the gluteals sorer than other exercises?
  19. How does stance width affect hip extension torque in squats?
  20. So is a wider squat stance width better?
  21. How does hip extension torque differ between normal, powerlifting and box squats?
  22. How does hip extension torque differ between taller and shorter lifters?
  23. How does hip extension torque differ with foot position in Smith Machine squats?
  24. How similar are the joint angles during the squat and deadlift?
  25. Can squat performance predict deadlift performance?
  26. How does stance width affect hip extension torque during deadlifts?
  27. So is the conventional or sumo stance better?
  28. How does skill level affect hip extension torque during deadlifts?
  29. How is hip extension torque different during straight and bent-leg deadlifts?
  30. How is hip extension torque different during hex-bar and conventional deadlifts?
  31. How does hip extension torque change with load during deadlifts?
  32. How much hip extension torque can powerlifters generate during deadlifts?
  33. How does load placement affect hip extension torque during sled dragging?
  34. What is the hip extension torque during a hip thrust?
  35. How do the torque curves of the key exercises compare?
  36. How does the total body effect of the key exercises compare?
  37. How does the effect of the key exercises on the glutes compare?

15. How does the proportion of hip extension torque change with increasing load/speed?

  1. Why study how the involvement of the hips changes with increasing load or speed?
  2. How does hip extension torque change with increasing load/speed?
  3. How does hip extension torque change with increasing squat load?
  4. How does hip extension torque change with increasing lunge load?
  5. How does hip extension torque change with increasing deadlift load?
  6. How does hip extension torque change with increasing running speed?
  7. How does hip extension torque change with increasing jumping height?
  8. How does hip extension torque change with increasing intensity?
  9. How does hip extension torque change with forward lean?

16. What are the directions for future research?

  1. What do we know that we don’t know?

Again, click HERE for the link.

35 thoughts on “Hip Extension Torque: The Scientific Guide to the Posterior Chain

  1. Shane

    Hey Bret, you mention this in the same sentence as Strong Curves without mentioning that Strong Curves (as far as I know) is a program for women. Is this for women as well? Is that why it’s focused on hip extension?

    Reply
    1. Bret Post author

      First of all, though Strong Curves is marketed toward women, it’s really not just a female program. I train this way! Men should prioritize glutes too.

      But to answer your question, no, Hip Extension Torque is for any scientifically-minded fitness fanatic.

      Reply
  2. Anna

    Hi Bret, I’ve got a herniated disk in my lower back and can’t do squats (only partial front squats), dead lifts and hip thrusts anymore. Have you got any suggestions on what I should/could do to work my glutes properly?

    Reply
    1. Bret Post author

      Anna, the first thing you need to do is not cripple yourself by thinking you can never do these lifts again. Discs heal in time and you need to be confident about that. As for what you can do now…single leg work, high rep bodyweight glute movements, band seated abductions, clams, side planks, x-band walks, and anything you can do that’s pain-free. Stay positive and don’t stop training!

      Reply
      1. Anna

        Bret, thank you very much for your reply!
        I think staying positive is the most important thing!
        Maybe you should really address this in full lenght on the blog. :)

        Reply
  3. Gary Hughes

    Hey Bret,
    I’ve just ordered your book can’t wait to start digesting your hard work.
    I hope I was in the first 100 customers because a 1 hour conference call with yourself would be awesome for my own personal development :)

    Reply
  4. Larry Milam

    Hey Bret, sounds like an exhausting but great job of work completed. What section specifically is geared toward rehab’ hip replacement clients? As u know traditional rehab only takes one so far!

    Reply
    1. Bret Post author

      Larry, there is a lot of information in here that will be beneficial for people who have recently undergone hip replacement. I agree – traditional rehab is not sufficient. It’s important to push the envelope further and keep strengthening those hips.

      Reply
  5. Anjuli

    I’m interested to know the answer to Anna’s Q as well. My husband herniated his low back (L4/L5) last year and cannot do squats, DLs, HT etc. anything that puts load to his back. What can he do (or not do) to strengthen his glute/posterior chain? He finished his PT etc and now works out from home… nothing specific at the moment. Thanks.

    PS: I am looking forward to Strong Curves next year :). Just Pre-ordered it. Would you recommend Strong Curves for Fat Loss as well? Is it a full body program or just focusing on posterior chain. TIA.

    Reply
    1. Bret Post author

      Anjuli, it’s all about gradual progression. I’m sure your husband can do squats with bodyweight or a weighted vest, there are tons of single leg exercises he can do, various planks and band walks, bodyweight posterior chain exercises, etc.

      There are powerlifters who have herniated discs and then gone on to break world records because they weren’t shackled by the nocebo effect.

      Gradual progression…one step at a time. Start wherever is pain-free and up the load, reps, ROM over time.

      Reply
  6. Lauren

    Hi Bret,thanks for your awesome labour in the sport world, I herniated my low back L5-S1 and I have the same problem that Anjuly and Anna, I do not know how improve my back chain properly without squats, deadlifts and hip thrust, please can you tell us any information about this? sorry for my english and the best wishes for your book

    Reply
    1. Bret Post author

      What in the heck is going on…3 questions about herniated discs in the same post!

      Okay, maybe I should address this on the blog and give it full attention. But I’ve given good advice so far.

      Start out with whatever doesn’t hurt. Make sure the core stays stable, the hips are mobile in all directions, and that good form is always adhered to. Gradually do more reps over time, up the load, move onto more challenging variations, etc.

      But it’s important to not do anything that’s painful. You can always work around things.

      Reply
      1. Anjuli

        ha ha ha :D
        PLEASE!! I (and others too, I’m sure) would LOVE a separate blog post on Herniated disc & training progression and if there is anything that you DON’T recommemd doing. You’re one of the few experts I do trust (honestly) and it would mean a lot.

        Hubby also has L5-S1 disc herniation.

        In the mean time, I will have him work on stuff based on your advice so far. THANK YOU!!

        Reply
  7. Ted

    “I was building the world’s greatest scientific library on the posterior chain.”
    “It’s unlike anything else I’ve ever seen (and I’ve seen it all).”

    Can you prove this, Bret? The world is big, you know.

    Reply
    1. Bret Post author

      Well, if this person is out there, they’re hoarding their knowledge haha! Cause I’d like to learn from that person as well.

      Reply
  8. Martos

    Hello Bret. Great work. I appreciate all the effort and bought your book. I have a question regarding knee flexion and full abduction: i don’t understand how knee flexion and full abduction can achieved both. Probably a silly question, but can you give an example of an exercise which does both? Thanks.

    Reply
    1. Bret Post author

      Martos, not sure if I understand your question…

      Which slide are you referring to? The flexibility slide showing hip extension range of motion measurements with different levels of hip abduction or knee flexion?

      If so, those just tested passive ranges of motion; they weren’t exercises.

      Reply
  9. Martos

    Hi Bret, i’m referring tot the slide on page 17 were different hip extension ROM measurments were taken. In the slide they speake of 80 degree knee flexion and full abduction. I’m trying to understand how the test was taken with what sort of movement that causes both knee flexion and hip adduction. Is it something like this picture:http://openi.nlm.nih.gov/detailedresult.php?img=2823204_ORT-1745-3674-80-314-g002&query=the&fields=all&favor=none&it=none&sub=none&uniq=0&sp=none&req=4&simCollection=2717149_ehp-117-a283f3&npos=17&prt=3

    Reply
  10. Sharon Althouse

    Hi Bret: just wanted also to put in my bid for your input on exercises for folks w/ back problems, mine is a burst L1, now with titanium cage and corpectomy of the 11 rib. L5S1 also giving me alot of pain. As a former gymnast I’m so discouraged by muscle/strength loss. This could be your niche market!!!

    Reply
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  14. Jennifer

    I recently had a partial meniscectomy I’m 5 weeks post op I was feeling fine and everything but yesterday I had like a numbness/tingling that goes from under my glute to about mid thigh on my non operated leg my glute feels sore and was wondering if this would help I’m not in pain but it’s annoying

    Reply
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