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Forming Thick Cables in Your Lower Back With Back Extensions |
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Written by Stephen E. Alway, PhD, FACSM
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Monday, 23 April 2007 |
Every bodybuilder knows he must be in full possession of a thick, wide back if he's to climb the ladder of competitive success. However, in the quest for a great wide upper and middle back, it's easy to forget about the muscles of the lower back; especially the muscles harbored close to the spine in the center of the back. After all, lat pulldowns and rows can take a lot out of you and then who has the energy to really think about something else for the lower back?
Of course there are other reasons to consider some additional effort for the lower back because a strong lower back can help keep you from sustaining any of those layoff-inducing injuries. While having a thick lower back doesn't mean all back injuries can be avoided, the likelihood of a serious injury from day-to-day or weekend sport activities is significantly lower if the erector muscles of the back are strong and developed. Back extensions will target the erector musculature surrounding the spine. This is a simple, yet very specific, exercise that will begin to pile on cable-like thickness to the muscles surrounding your spine. Nevertheless, anytime you train the lower back directly, you must maintain a high level of concentration and care. While weight training is definitely the best way to reduce the risk of back injury, sloppy exercise form could itself be responsible for the pain you're trying to avoid.
Lower Back Structure and Function
Back extensions strongly activate a group of three postural muscles situated along the spine collectively called the erector spinae. The iliocostalis muscle is the most lateral of the erector spinae group. It arises from the iliac crest (part of the hip bone), runs toward the head and inserts into the ribs. The intermediate muscle of the erector spinae group is the longissimus muscle. This muscle runs almost the entire length of the back. Its fibers arise from the lateral bony projections of the vertebrae called transverse processes and the fibers insert on transverse processes of vertebrae, which are more superior.
The spinalis muscle is the most medial column of the erector spinae and essentially runs up the center of the back. Specifically, it arises from the spinous processes (small projections that lie directly in the center of the vertebrae) in the lumbar and lower thoracic regions, which insert into the spinous process of superior portion in the thoracic and neck (cervical) regions. The thoracolumbar fascia covers these muscles posteriorly. This is a tough sheet of connective tissue (fascia) that doesn't have much flexibility. Thus, it's prone to injuries from extreme stretching or jerking. The erector spinae lie just deep to this fascia covering.
Collectively, the erector spinae group represents the strongest extenders of the vertebral column. Acting on one side of the body at a time, each of these muscles can bend the vertebral column laterally (e.g., in side bends). The three-erector spinae muscles can also act to rotate the vertebral column in a twisting action. The iliocostalis is the best rotator of the vertebral column. The remaining two muscles will, however, invoke some rotation along the spine.
The hamstring muscles also strongly contract during back extensions. The biceps femoris muscle is named appropriately because it's a two-("bi") headed muscle on the posterior thigh ("femoris"; the femur is the thigh bone). The long head attaches to the ischial tuberosity of the low hipbone structure. The fibers of the short head begin on the lower one-third of the femur bone just above the knee and because they don't attach to the ischial tuberosity, the short head isn't considered a "hamstring" muscle. Both heads of the muscle fuse into a thick tendon, which crosses the lateral side of the knee joint to attach to the fibula bone (and some ligaments) on the knee. The second muscle of the hamstring group is the semitendinosus. The semitendinosus muscle is part ("semi") tendon ("tendinous") and part muscle. The semitendinosus fibers attach to the ischial tuberosity and inserts into a cord-like tendon about two-thirds of the way down the posterior thigh. The semitendinosus crosses the knee joint posteriorly to attach to the medial side of the superior part of the tibia (the large medial bone of the leg). Although both hamstring muscles flex the knee, because they cross the hip joint posteriorly, they become important extensors of the back and will assist the erector spinae during back extensions.
Back Extensions
Back extensions are sometimes called "hyperextensions." The lower back can achieve a limited amount of hyperextension of the lumbar and thoracic vertebrae. Hyperextension of the vertebrae occurs when the extension goes beyond the point where the spine is in a straight line with the hip. This is recognized as an "arch" in the lower back. Generally, the "hyper" in back extension exercises should be avoided because an excessive (hyper) back extension can result in the vertebral discs becoming compressed and the nerves that exit between the vertebrae will achieve the same undesired fate.
Proper Exercise Form
1. Lie face down on a back extension bench (perhaps called the hyperextension bench in your gym). Most of the modern machines will have a pad crossing the front part of your hips/pelvis. Position yourself with your knees almost (but not quite) straight. The bench pad should be comfortably placed across the pelvis and not low on the thighs or high on the abdomen.
2. On most benches, you can place your lower leg under pads or rollers to anchor you during the movement. The pads should be placed between mid-calf and ankle.
3. The first "warm-up" set will be done without extra resistance. Cross your arms and lay them across your chest. Inhale and then exhale as you lower your upper body toward the floor by bending (flexing) at the waist/hip.
4. Begin with a 90 degree angle between your upper and lower body, then extend your back by lifting the torso until your back is parallel to the floor and there's a straight line through your back, hips and lower legs. Don't lift higher than this to hyperextend the back. The force should come smoothly (no jerking or fast movements should occur) from your erector spinae muscles. Inhale as you come up on the movement.
5. After the extension is complete, slowly reverse your direction and control the lowering of the weight of your upper body until it's just short of the starting position, then repeat for a total of 15-20 repetitions. This will maintain tension on the muscles throughout the effort.
The erector spinae muscles act as primary spine movers, by extending the back at the hip and moving the torso upward from a flexed position. However, as indicated above, the hamstring muscles are strong hip extensors and they will also be active in back extensions. It's worth taking the time to stretch your hamstring muscles and back between sets of back extensions. You can do this by standing, straightening your knees and try to bring your head and chest toward your thighs for four or five stretches held for 10 seconds each. If you do a lot of sitting each day as part of your job, your hamstrings will almost certainly be tight and this could contribute to lower back pain; however, stretching should eliminate the tight muscles.
On your second set you can hold a barbell plate across your chest while you control the extension (upward movement) and flexion (downward movement) of each repetition. You can induce a little more effort from the erector spinae if you hold the upper body at the top position for two to three seconds in each repetition. Don't swing your torso upward. Both the up and down phases of each repetition should be slow and controlled. The key to injury-free exercise while you're building thick erector cables is to maintain strict control of your body, especially when holding the extra resistance. Your erector muscles will get thicker and denser with the added resistance, so don't hesitate to pile on the weight, but again, keep each movement slow and controlled. Make sure you don't "hyperextend" your back by going above a position parallel to the floor, unless you like to challenge the ability of your intervertebral discs to withstand rupturing.
Three or four sets of weighted back extensions of 12-15 reps will thoroughly activate the fibers in your spine and lower back and this will also generate a full throbbing lower back pump. You may wish to avoid heavy squats the next day, especially if your lower back has not fully recovered. However, it will recover, grow stronger and the cables on each side of your spine will enlarge and thicken. Back extensions can complete a trophy winning back that extends with thickness and width from the base of your skull to the hips. You'll soon see your new deep and thick erector muscle cables can help you launch you back toward bodybuilding greatness.
References
1. Albert WJ, Sleivert GG, Neary JP and Bhambhani YN. Monitoring individual erector spinae fatigue responses using electromyography and near infrared spectroscopy. Can J Appl Physiol, 29: 363-378, 2004.
2. Cussler EC, Lohman TG, Going SB, Houtkooper LB, Metcalfe LL, Flint-Wagner HG, Harris RB and Teixeira PJ. Weight lifted in strength training predicts bone change in postmenopausal women. Med Sci Sports Exerc, 35: 10-17, 2003.
3. Davidson KL and Hubley-Kozey CL. Trunk muscle responses to demands of an exercise progression to improve dynamic spinal stability. Arch Phys Med Rehabil, 86: 216-223, 2005.
4. Kollmitzer J, Ebenbichler GR, Sabo A, Kerschan K and Bochdansky T. Effects of back extensor strength training versus balance training on postural control. Med Sci Sports Exerc, 32: 1770-1776, 2000.
5. Mayer JM, Udermann BE, Graves JE and Ploutz-Snyder LL. Effect of Roman chair exercise training on the development of lumbar extension strength. J Strength Cond Res, 17: 356-361, 2003.
6. Plamondon A, Serresse O, Boyd K, Ladouceur D and Desjardins P. Estimated moments at L5/S1 level and muscular activation of back extensors for six prone back extension exercises in healthy individuals. Scand J Med Sci Sports, 12: 81-89, 2002
7. Plamondon A, Trimble K, Lariviere C and Desjardins P. Back muscle fatigue during intermittent prone back extension exercise. Scand J Med Sci Sports, 14: 221-230, 2004.
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