Monthly Archives: March 2012

The Gluteus Maximus Activation Enigma – A Blurb

I was originally going to do a little write-up on Vladmir Janda’s prone hip extension (PHE) test, but I found that Dr. Greg Lehman has already done a great job with the topic on his blog. As Dr. Lehman mentioned, we really don’t know what to take from this test from a research perspective. Clinically, many have seen that this test does demonstrate test-retest changes with a successful outcome in a treatment. In fact, I have observed a clinical example in which a patient with hip pain had been participating in numerous closed and open chain exercise interventions that involved hip extension and hip abduction to address their hip pain with no improvement. Yet, ultimately a single prone exercise which emphasized conscious effort to perform isometric gluteal contraction completely resolved her year long struggle with hip pain. Despite this clinical evidence, little research regarding injury and the gluteus maximus has been performed. I thought I’d do a quick blurb on some of the few studies which have shown some correlation between gluteus maximus activation and any injury.

Bullock-Saxton, Janda, and Bullock demonstrated a correlation between ankle sprain injury and an increased delay in gluteal activation2. Similarly, Bruno and Bagust demonstrated an increased delay in gluteal activation in low back pain (LBP)1. One concern with both of these studies were that they utilized the PHE test, in which Dr. Lehman already pointed out previous research showing inconsistencies in activation patterns including the relevance of the gluteus maximus delay. Further yet, since the PHE is performed in “prone”, we have remember, as Gary Gray likes to point out, everything changes once the foot hits the ground. Vogt and his team examined muscle activation patterns in both an LBP and asymptmatic population during walking. In their study, they demonstrated that both the gluteus maximus and the erector spinae were active for a prolonged period of time in an LBP population and that, oddly enough, the glut max fired earlier (although so did the erector spinae and hamstrings) in the gait cycle than the asymptomatic population5. Likewise, during standing extension from a full flexed position, Leinonen et al. demonstrated that in a LBP population, the glut max  fired earlier than the erector spinae4. So wait, aren’t we trying to get the glutes to fire earlier as a result of our treatment, or possibly even longer, in the thought of protecting the spine? However, research seems to indicate the body is already trying to do it for us.

So here in lies our enigma regarding gluteus maximus activation and our beliefs regarding its role in musculoskeletal dysfunction. Clinically we’re seeing results with what we perceive to be our gluteal emphasized exercise prescriptions, but it might not be for the reasons we think. As Dr. Lehman mentioned, we may be looking at the wrong variable of gluteal function, perhaps it is peak amplitude or glute max endurance3? Or perhaps our treatments are effecting something else entirely, and simply performing a neuromuscular extensor pattern in the “region of dysfunction” is enough to get a therapeutic benefit (a good future blog topic!).  Regardless, we need to be open to alternative explanations for the gluteus maximus enigma, in particular if those explanations come with improved outcomes.

1. Bruno PA, Bagust J. An investigation into motor pattern differences used during prone hip extension between subjects with and without low back pain. Clinical Chiropractic. 2007;10(2):68-80. doi: 10.1016/j.clch.2006.10.002.

2. Bullock-Saxton JE, Janda V, Bullock MI. The influence of ankle sprain injury on muscle activation during hip extension. Int J Sports Med. 1994;15(6):330-334. doi: 10.1055/s-2007-1021069.

3. Kankaanpaa M, Taimela S, Laaksonen D, Hanninen O, Airaksinen O. Back and hip extensor fatigability in chronic low back pain patients and controls. Arch Phys Med Rehabil. 1998;79(4):412-417.

4. Leinonen V, Kankaanpää M, Airaksinen O, Hänninen O. Back and hip extensor activities during trunk flexion/extension: Effects of low back pain and rehabilitation. Arch Phys Med Rehabil. 2000;81(1):32-37. doi: 10.1016/S0003-9993(00)90218-1.

5. Vogt L, Pfeifer K, Banzer W. Neuromuscular control of walking with chronic low-back pain. Man Ther. 2003;8(1):21-28.

3D/Tri-planar Stretching

I first heard about 3D/Tri-planar stretching from the Michael Boyle Functional Strength Coach 3.0 video series around 2009. Similarly, Gary Gray completely encompasses the 3D movement paradigm in his functional training programs.  I am not entirely sure the full history behind 3D stretching,  but I will take tremendous liberty to assume it likely started with Thomas Meyer’s Anatomy Trains. This brilliantly written and illustrated work has provided us one of the most detailed reviews and perspectives of the myofascial connections of the body and their respective lines of pull in static positions and with movement. Taking it back even further, we will see that the work of Herman Kabat with the diagonal patterns of PNF also brought tremendous insight into the spiral-like function of muscular and fascial movement in the human body. In retrospect, many of us could clearly have seen in dissections and even in textbooks evidence of muscle and fascia functioning in three dimensions, but we still needed some smart thinkers to remind us that perhaps we should look at treating the movement restriction in more than one plane of motion from time-to-time.

There are numerous ways to perform 3D stretches throughout the body. Popularized systems including Yoga and Pilates have long since incorporated them and intuitively most of us can figure out a number of ways to stretch muscles in multiple planes on our own. The question is, is it better to address a movement restriction globally (3D stretch), or locally (single plane)? It is vital to note that the value of each of these stretches depends on the individual and their specific movement limitations. To be honest, I still find single plane stretches to be the most effective use of time in most cases, in particular when it comes to addressing specific restrictions. In fact, I generally limit the use of 3D stretches to the upper extremity and the hamstrings because I can often times address both a local restriction and global restrictions very effectively in these areas with a single stretch. For the purpose of this post and for this video I am only going to speak of 3D stretching through the hamstrings.

3D/Tri-planar Stretching – Hamstring Emphasized

The attachment of the biceps femoris to the sacrotuberous ligament and the fascial attachments of the erector spinae provides a fairly common restricted line of pull for most individuals. It is very easy to feel the tension throughout this chain/train and it is easy to self-manage. Plus, as I mentioned earlier, I can emphasize a local restriction by passively holding the hamstrings in a lengthened position in a sagital plane and gradually incorporate lengthening of the rest of the fascial chain as needed. From the perspective of Anatomy Trains, with the hamstrings (specifically the biceps femoris) fascial attachment to the sacrum we can take advantage of the Superficial Back Line, the Spiral Line, and the Back Functional Line to lengthen numerous fascial restrictions. From a PNF philosophy, we are lengthening through D1 and D2 hip extension  and increasing ROM into D1 & D2 hip flexion.

That’s enough writing, here is a video of me demonstrating and discussing some options for 3D/Tri-planar hamstring stretching.

Long-Term Static Stretching

I previously wrote a post on the topic of acute stretching, injury, and performance and recently published a study in the same vein in the Journal of Strength and Conditioning Research. At that time, I made only a brief reference to long-term stretching. A recent article regarding a long-term static stretching intervention resulting in strength increases in the contralateral muscle from Nelson et al. 12 inspired me want to write a little more about long-term stretching.

What do we know about the effects of long-term stretching? At this time, we know we can use it to improve static range of motion (ROM)8,9, muscle strength, endurance, and power 7,8. There is also some evidence that long-term (again not acute!) stretching has a role in decreasing musculotendinous injury2.  The mechanism involved in producing improvements in ROM from long term stretching is unknown at this time. Classically, the belief was that we are primarily “lengthening the muscle”. However, ROM improvements related to long-term static stretching appear to be largely related to increased stretch tolerance and not an actual changes in tissue extensibility 3,5,9, which would indicate some sort a neurological influence. The exact mechanism for the strength, endurance, power, and injury prevention benefits are also unknown, but a couple of thoughts seem to permeate. The first being that hypertrophy of skeletal muscle tissue and/or connective tissue may play a role, but this has only been demonstrated in animal studies 14.  Which brings us to a neural influence. We typically think about the neural influences of stretching on the acute effects of performance, but between previous evidence3,5,9 and now Nelson et al. 12, I am hedging a bet towards long term neural adaptation being a key component in the positive outcomes of long-term stretching.

Briefly, Nelson et al. examined  the cross training effect of a 10-week static stretching in an untrained population (important note) on calf strength which demonstrated a 29% increase (higher than contralateral resistance training studies!) in strength of the contralateral calf, as well as a statistically significant 1% increase in ROM for the contralateral calf12.  This change in ROM may seem minimally relevant, but the fact that there was a detectable change in ROM of the contralateral limb may provide additional support for a neurological influence in this change. This is because if hypertrophy had occurred, increased tendon stiffness would likely be noted 15, which probably would have prevented a detectable change in calf ROM. Further yet, previous examinations on unilateral resistance training and its effect on the contralateral limb demonstrated strength increases in the absence of hypertrophy11 and appear to be related to neurological changes4, and there is little reason to believe the effects of stretching would be different than resistance training.

So what is the practical application of this discussion? Mechanism wise, whether hypertrophy or neural based, it doesn’t matter, both are synergistic benefits of long term training. The fact that there are physiological changes with concurrent performance improvements indicate a value in us maintaining or adding a long-term stretching regimen.

More specifically, most athletes can benefit from increasing static ROM. I state this with some caution as there definite risks with excessive flexibility, in particular at the spine. Greater flexibility of the lumbar spine is associated with disc degeneration6,17, and excess flexion and rotation are associated with disc herniation1,10.

Regarding improvements in muscle strength, power, and endurance, these benefits have only been demonstrated in the untrained population7,8,12, so it is difficult to apply to the higher level athlete because neural changes primarily are a part of early training with the influences of hypertrophy primarily playing a role in later gains. As stated by Nelson et al., there may also be a benefit in managing strength loss in an immobilized limb12.

Ultimately, the most practical application for chronic long-term stretching may lie in prevention of musculotendinous injury , although only one study has provided evidence for this proposal2. It appears that this injury reduction is the result of a training response over time, not an isolated occurrence, not in relation to pre-exercise stretching, but a long-term adaptation. As has been repeated to death at this point, no evidence for pre-exercise stretching reducing injury risk currently exists2,13,16,18, but a long-term relationship does exist, and justification for static stretching over time as a method to reduce injury risk is very plausable. There is some suggestion and guidance to the exclusive emphasis on dynamic stretching with no thought towards a post-exercise or separate static stretching sessions, and this may come at the detriment of some benefits we still do not understand. Needless to say, beyond the time commitment, unlike pre-exercise static stretching, there really is no evidence to demonstrate a negative impact of post-exercise static stretching or independent static stretching sessions.

So now it is your turn. What are your thoughts regarding keeping or adding a long-term stretching intervention? Is it worth the time it takes to keep or add it in your program?

1. Adams MA, Hutton WC. Prolapsed intervertebral disc. A hyperflexion injury 1981 volvo award in basic science. Spine (Phila Pa 1976). 1982;7(3):184-191.

2. Amako M, Oda T, Masuoka K, Yokoi H, Campisi P. Effect of static stretching on prevention of injuries for military recruits. Military Medicine. 2003;168(6):442-446.

3. Ben M, Harvey LA. Regular stretch does not increase muscle extensibility: A randomized controlled trial. Scand J Med Sci Sports. 2010;20(1):136-144. doi: 10.1111/j.1600-0838.2009.00926.x.

4. Fimland MS, Helgerud J, Solstad GM, Iversen VM, Leivseth G, Hoff J. Neural adaptations underlying cross-education after unilateral strength training. Eur J Appl Physiol. 2009;107(6):723-730. doi: 10.1007/s00421-009-1190-7.

5. Folpp H, Deall S, Harvey LA, Gwinn T. Can apparent increases in muscle extensibility with regular stretch be explained by changes in tolerance to stretch? Aust J Physiother. 2006;52(1):45-50.

6. Fujiwara A, Lim TH, An HS, et al. The effect of disc degeneration and facet joint osteoarthritis on the segmental flexibility of the lumbar spine. Spine (Phila Pa 1976). 2000;25(23):3036-3044.

7. Kokkonen J, Nelson AG, Tarawhiti T, Buckingham P, Winchester JB. Early-phase resistance training strength gains in novice lifters are enhanced by doing static stretching. J Strength Cond Res. 2010;24(2):502-506. doi: 10.1519/JSC.0b013e3181c06ca0.

8. Kokkonen J, Nelson AG, Eldredge C, Winchester JB. Chronic static stretching improves exercise performance. Med Sci Sports Exerc. 2007;39(10):1825-1831. doi: 10.1249/mss.0b013e3181238a2b.

9. Magnusson SP. Passive properties of human skeletal muscle during stretch maneuvers. Scandinavian Journal of Medicine & Science in Sports. 1998;8(2):65-77.

10. Marshall LW, McGill SM. The role of axial torque in disc herniation. Clinical Biomechanics. 2010;25:6-9.

11. Munn J, Herbert RD, Gandevia SC. Contralateral effects of unilateral resistance training: A meta-analysis. J Appl Physiol. 2004;96(5):1861-1866. doi: 10.1152/japplphysiol.00541.2003.

12. Nelson AG, Kokkonen J, Winchester JB, et al. A 10-week stretching program increases strength in the contralateral muscle. J Strength Cond Res. 2012;26(3):832-836. doi: 10.1519/JSC.0b013e3182281b41.

13. Pope RP, Herbert RD, Kirwan JD, Graham. A randomized trial of preexercise stretching for prevention of lower-limb injury. Medicine & Science in Sports & Exercise. 2000;32(2):271-277.

14. Sasai N, Agata N, Inoue-Miyazu M, et al. Involvement of PI3K/Akt/TOR pathway in stretch-induced hypertrophy of myotubes. Muscle Nerve. 2010;41(1):100-106. doi: 10.1002/mus.21473.

15. Seynnes OR, Erskine RM, Maganaris CN, et al. Training-induced changes in structural and mechanical properties of the patellar tendon are related to muscle hypertrophy but not to strength gains. J Appl Physiol. 2009;107(2):523-530. doi: 10.1152/japplphysiol.00213.2009.

16. Shrier I. Stretching before exercise does not reduce the risk of muscle injury: A critical review of clinical basic science literature. Clinical Journal of Sport Medicine. 1999;9(4):221-227.

17. Tanaka N, An HS, Lim TH, Fujiwara A, Jeon CH, Haughton VM. The relationship between disc degeneration and flexibility of the lumbar spine. Spine J. 2001;1(1):47-56.

18. Thacker SB, Gilchrst J, Stroup D, Kimsey D. The impact of stretching on sports injury risk: A systematic review of literature. Medicine & Science in Sports & Exercise. 2004;36(3):371-378.

Blog is live

The blog is finally up. Posting to start sometime in the near future.