Guest guest Posted May 11, 2007 Report Share Posted May 11, 2007 Wayne Boesmans wrote: Even with the study you presented about weightlifting belts, I do not see how increased IAP relates to axial loading. Even if the increased IAP allows the spine to elongate (as above) this would be limited to the areas covered by the belt, or at best to the area covered by IAP, between the pelvic floor muscles and the diaphragm. What about thoracic or cervical spine disc damage? Casler writes: Hi Wayne, I don't recall reading the original post, but to add a bit of info regarding belts and IAP. Belts in competition are worn to create an " encasement " of the Lumbar Spine. While the Lumbar Spine have the largest vertebrae and discs, they also have little anterior support. Encasing this basically soft tissue area provides that support. Your question regarding the Thoracic Spine is certainly valid, and when one examines the Thoracic vertebrae and discs it seems an amazing feat in engineering that they are not crushed. That is until you broaden your view and understand that the ribcage is part of the thoracic spine. As well, to create high levels of IAP, you must first create rather high levels of ITP. This pressurization of the Thoracic Torso, along with the cocontraction of the musculature in the area, provides a variable support through it total crossectional area and not just the spine and disc structures as many limit their observation/analysis to. Then adding the belt to the ab/torso area just beneath the ribs, adds again a rather large crossectional area to distribute and manage the load forces. Now, IAP and ITP forces are controllable and modulated via valsalva, and muscular contractions. They are also not sufficient on their own to support all loads. But they, along with all the other elements of the TSM (Torso Stabilization Mechanism) can manage huge loads with relative safety. Simply " containing " these pressures adds strength through load distribution (like standing on a Coke can when full and not open, versus standing on and " crushing " a Coke can when empty and open) Another illustration I have used to provide a look into the what happens is taking your hand and squeezing a full tube of toothpaste in the center. If you squeeze hard enough, toothpast will squirt out either end. This displays the ability of containment of force to direct/re-direct the force, in a way that shows how you have a supportive force to axial loads in some areas. You might also visualize your hand around the tube as a very tight belt. More importantly however, is the fact that the belt and these pressures contribute to the resistance to anterior disc compression. Regards, Casler TRI-VECTOR 3-D Force Systems Century City, CA Quote Link to comment Share on other sites More sharing options...
Guest guest Posted May 13, 2007 Report Share Posted May 13, 2007 Greetings Wayne, “Hyperextension” is actually a bad term. We call it the Back Extender (BE) Exercise aka back raises and instruct each to extend only to their “normal” ability of spinal extension. I have taught thousands of the years and find the only limiting factors of extension performing BE are facet joint arthrosis. Even spondylolisthesis upto grade II have done very well with this exercise. I have patients and the sporty folks under care three ways to perform the exercise. I have short video clips of each of the following I can post to you anyone else - contact me directly. 1. With the restraint behind the heels ER as well as the hip extensors are worked. I feel those that feel it in the hamstrings (typical) have week hamstrings. 2. To isolate ER the restraint is placed behind the knees which limits hip extension. 3. To isolate gluts and hamstrings the restraint is place behind the heels but maintaining an isometric contraction of ER in a lordotic lock. Olympic lifters use this with weight to target hip extensors as well as reinforcing the lordotic lock. Weightlifting belt dynamics as noted before are still an enigma. Increased IAP IMO distributes the axial load more across the entire trunk – for me it’s a no-brainer. But, as mentioned earlier, we have to wait for the science. With overhead compression exercises (olympic lifts) the thoracics take a hit – as I can personally testify to. Cervical spine should not be a problem unless you drop the bar on your head, which, again I have done. I just read Cashler’s post and I feel he has explained this the best I have read. Cheers – Dr J , MSc, DC Whangarei NEW ZEALAND > , > > Quote: " Hyperextensions target spinal extensor muscle groups (erector > spinae) in non-weight bearing and aid in maintaining spinal flexibility. > The emphasis is on endurance rather than strength to develop better > stability. " > > I could agree with that. First let me explain I view hyperextensions as > those exercises done in a prone position, extending the back beyond the > " neutral position " , often called supermans. Back extensions are those > exercises done on a back extension bench (either horizontal or incline) > where the hips & feet are supported/anchored and the upper body hangs > down, before the upper body is brought up to a " neutral position " or > further into hyper extension. The " back " extension, to me, works the > hamstrings and glutes probably more than it does the spinal extensors. > Additionally, if I program such exercises/benches for spinal extensors I > will vary the placing of the hip pads, to allow for actual " back > extension " instead of " hip extension " (if the body hangs far enough over > the pads, the UB can be held easily in a neutral position and the only > flexion/extension taking place is at the hips). And/or I will instruct > the client to flex/extend the upper body (as in abdominal curls) to get > proper spinal extensor involvement. The erector spinae have been proven > to benefit more from endurance type work, but I doubt hyperextensions > (or back extensions) do much for spinal extensor flexibility. No doubt > both endurance type work and flexibility would benefit spinae & general > back health. Muscular endurance and flexibility of the spinae could > benefit axial loading in that it " opens up " or " elongates " the spine, > thereby reducing possible pressure on the discs, pressure that may/will > cause disc damage. > > Even with the study you presented about weightlifting belts, I do not > see how increased IAP relates to axial loading. Even if the increased > IAP allows the spine to elongate (as above) this would be limited to the > areas covered by the belt, or at best to the area covered by IAP, > between the pelvic floor muscles and the diaphragm. What about thoracic > or cervical spine disc damage? > > Wayne Boesmans > Brisbane, QLD > > > Dr J wrote: > >> Wayne, >> >> Hyperextensions target spinal extensor muscle groups (erector spinae) in >> non-weight bearing and aid in maintaining spinal flexibility. The >> emphasis is on endurance rather than strength to develop better >> stability. >> >> There is still much controversy regarding the use of weightlifting >> belts. Stuart McGill in his 2002 text summarises the scientific studies >> with no definite evidence regarding reducing compressive forces on the >> lumbar spine. Below is a 1999 published study which gives some support, >> which BTW McGill did not include in his record review. However, from my >> 26 years of very successfully putting Valeo belts on back injured >> labourers plus my personal use of the belt, my feeling is that benefit >> comes from the trunk muscle pushing out against the belt resulting in >> increased IAP and decreased axial loading on the lumbar discs. While >> there is yet valid research to support the latter assumption, hopefully >> that will be forthcoming. I expect some IT genius will develop a >> wireless pressure measuring device which can be inserted at L3/4 and >> L4/5 discs in a statistically significant number of volunteers in order >> to rule in or out what I feel is an obvious assumption. >> >> Clin Biomech (Bristol, Avon). 1999 Feb;14(2):79-87. >> Effects of abdominal belts on intra-abdominal pressure, intra-muscular >> pressure in the erector spinae muscles and myoelectrical activities of >> trunk muscles. >> Miyamoto K >> <http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & term=%22Miya\ moto+K%22%5BAuthor%5D>, >> Iinuma N >> <http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & term=%22Iinu\ ma+N%22%5BAuthor%5D>, >> Maeda M >> <http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & term=%22Maed\ a+M%22%5BAuthor%5D>, >> Wada E >> <http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & term=%22Wada\ +E%22%5BAuthor%5D>, >> Shimizu K >> <http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed & cmd=Search & term=%22Shim\ izu+K%22%5BAuthor%5D>. >> Department of Orthopaedic Surgery, Gifu University, School of Medicine, >> Japan. kei@... >> >> OBJECTIVE: To evaluate the effects of abdominal belts on lifting >> performance, muscle activation, intra-abdominal pressure and >> intra-muscular pressure of the erector spinae muscles. >> >> DESIGN: Simultaneous measurement of intra-abdominal pressure, >> intra-muscular pressure of the erector spinae muscles was performed >> during the Valsalva maneuver and some isometric lift exertions. >> >> BACKGROUND: While several hypotheses have been suggested regarding the >> biomechanics of belts and performance has been found to increase when >> lifting with belts, very little is known about the modulating effects on >> trunk stiffness. At present, there is no reason to believe that spine >> tolerance to loads increases with belts. >> >> METHODS: An abdominal belt designed for weightlifting was used. >> Intra-abdominal pressure, intra-muscular pressure of the erector spinae >> muscles and myoelectric activities of trunk muscles (erector spinae, >> rectus abdominis and external oblique) were measured simultaneously >> during the Valsalva maneuver as well as three types of isometric lifting >> exertions (arm, leg and torso lift). A paired t-test was used to analyze >> for statistical differences between the two conditions (without-belt and >> with-belt) in intra-abdominal pressure, intra-muscular pressure of the >> erector spinae muscles and in the integrated EMG of the trunk muscles. >> >> RESULTS: Intra-muscular pressure of the erector spinae muscles increased >> significantly by wearing the abdominal belt during Valsalva maneuvers >> and during maximum isometric lifting exertions, while maximum isometric >> lifting capacity and peak intra-abdominal pressure were not affected. >> Integrated EMG of rectus abdominis increased significantly by wearing >> the abdominal belt during Valsalva maneuvers (after full inspiration) >> and during isometric leg lifting. >> >> CONCLUSIONS: Wearing abdominal belts raises intra-muscular pressure of >> the erector spinae muscles and appears to stiffen the trunk. Assuming >> that increased intra-muscular pressure of the erector spinae muscles >> stabilizes the lumbar spine, wearing abdominal belts may contribute to >> the stabilization during lifting exertions. >> >> Dr J , MSc, DC >> Whangarei >> NEW ZEALAND >> >> Wayne Boesmans wrote: >> >> >>> Dr , >>> >>> How do hyperextensions relate to " heading off " disc damage? >>> How does wearing a weightlifting belt relate to axial loading of the spine? >>> >>> Thanks >>> Wayne Boesmans >>> Brisbane, QLD Quote Link to comment Share on other sites More sharing options...
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