What are the flaws of the musculoskeletal system?
Actually, you're both correct on this. Other than back pain caused by injuries while lifting improperly, a sedentary lifestyle is a risk factor for back pain. Weak muscles put people at higher risk of back injuries and/or pain.misskitty said:This isn't a correct statement since pain in the lower back is attributed to the fact humans used to walk on all fours, but when they became bipedal the spinal column did not advance as much as it should have. If it had the lower portion of the spinal column would much thicker and stronger than it is right now.
http://adam.about.com/reports/000054_3.htmSedentary Lifestyle. People who do not exercise regularly face an increased risk for low back pain, especially during times when they suddenly embark on stressful unaccustomed activity, such as shoveling, digging, or moving heavy items. Although no definitive studies have been done to prove the relationship between lack of exercise and low back pain, sedentary living is probably a primary nonmedical culprit contributing to this condition. Lack of exercise leads to the following conditions that may threaten the back:
Muscle inflexibility (can restrict the back's ability to move, rotate, and bend).
Weak stomach muscles (can increase the strain on the back and can cause an abnormal tilt of the pelvis).
Weak back muscles (may increase the load on the spine and the risk for disc compression).
Obesity, associated with sedentary lifestyle (may put more weight on the spine and increase pressure on the vertebrae and discs). Studies report only a weak association between obesity and low back pain, however.
http://neurology.health-cares.net/lower-back-pain.phpThe most common type of back pain is lower back pain. That's because the lower portion of the back is under the most pressure when a person is sitting or lifting, and it can be easily damaged. Lower back pain is pain in the low lumbar, lumbosacral, or sacroiliac region, possibly accompanied by pain radiating down one or both buttocks or legs in the distribution of the sciatic nerve (sciatica). The lower back is an elegant construction of bone, muscle, and ligament. Because the lower back is the hinge between the upper and lower body, it is especially vulnerable to injury when you are lifting, reaching, or twisting. When low back pain strikes, we become acutely aware of just how much we rely on a flexible, strong back. Ironically, most of us don't think of the importance of keeping our back and stomach muscles strong until we have back trouble. The lower back supports most of the body’s weight, and as a result, is susceptible to pain caused by injury or other problems. Over 80% of adults experience low back pain (LBP) sometime during their life.1 More than half will have a repeat episode.
http://familydoctor.org/117.xml [Broken]Is there relief for ongoing back problems?
Treatment of ongoing back problems must be directed at the cause. This may mean losing weight (because being overweight can make back pain worse), getting your muscles in better shape, and improving your posture when you're sitting, standing and sleeping.
Tips for preventing back strain
Don't lift by bending over. Lift an object by bending your hips and knees and then squatting to pick up the object. Keep your back straight and hold the object close to your body. Avoid twisting your body while lifting.
Push rather than pull when you must move heavy objects.
If you must sit at your desk or at the wheel of a car or truck for long hours, break up the time with stops to stretch.
Wear flat shoes or shoes with low heels (1 inch or lower).
Exercise regularly. An inactive lifestyle contributes to lower back pain.
http://www.doctorndtv.com/lifestyle/exerdetailtopics.asp?id=24Benefits of exercise for back pain
For many people, the key to a healthy back is proper exercise. You can minimise the problems related to back pain with exercises. These exercises make the muscles in your back, stomach, hips and thighs strong and flexible. Some exercises help to strengthen your back and stomach muscles, while other exercises are designed to improve your posture. A 30-minute aerobic conditioning program three times a week is ideal for overall fitness. Walking and/or water exercise are highly recommended for most people with back problems.
http://www.pbs.org/wgbh/evolution/library/07/3/text_pop/l_073_08.html[When you compare] a human vertebra, a chimpanzee vertebra, [and] the vertebra of a lemur, you can see that the human and the chimpanzee are much more similar to each other when compared to the lemur. That's because the human and the chimpanzee have adaptations for upright posture. The human and the chimp vertebrae are very short. They also have fewer vertebrae, which makes for a short spine, which is very stable in upright posture. In comparison, the lemur has elongated vertebrae and more vertebrae, which gives it a lot of flexibility and a wider range of motion for their quadrupedal movements.
Q: What are the differences between humans today and our closest living relatives, chimps, that allow us to be bipedal while they really aren't?
A: If you compare the human body to that of a chimpanzee, there are a lot of similarities in the upper body: the arms, the chest, the upper trunk. But there are many changes from the waist down, many differences between humans and chimpanzees that allow us to walk bipedally all the time. For example, in the lower back humans have a curve, a forward curve called lordosis, that you don't see in any other primate, which allows us to balance our upper body over our legs. The vertebrae themselves are much bigger in humans relative to body size than in any other primate, which allows us to bear the loads which are coming from the upper body through the lower back all day.
http://www.sciencemag.org/cgi/content/summary/311/5764/1071Evolution is also the origin of apparent anatomical anomalies such as the vulnerabilities of the lower back.