Monday, January 12, 2015

There is sadness in watching two elite players battle through injury, attempting to play a violent game like football. Quarterbacks lead as much as their bodies allow and in the case of Aaron Rodgers and Tony Romo facing each other in a playoff game, the fans were not able to see their peak performance as they limped around the field. Elite athletes try to overcome injuries, but it’s tough to beat anatomy and physiology.

Limping is not normal. There are numerous causes to limp from skeleton abnormalities to muscleand nerve disease, but the most common cause is physical trauma. Pain is the body’s protective mechanism and when an injury occurs, pain sensors tell the central nervous system to shut down that part of the body. When it comes to an injury to the back, pelvis or leg, that means trying hard to have the body avoid weight bearing.

The phases of gait include the stance phase followed by a swing phase. One cycle equals a foot strike followed by a swing of the leg until that foot strikes again (stance to swing to stance). There are two parts to the stance phase which makes up 60% of the cycle: one foot on the ground and two feet touching. At normal walking speed, both feet are on the ground at the same time for about 10% of the time, but as speed increases, this time decreases until there is almost no time that both feet are touching the ground at the same time (think sprinter). The joints and muscles of the leg not only have to propel the body forward but also have to dissipate the shock of landing. With each step or stride, the force generated is many times the body’s weight and it’s the structures of the lower body that have to absorb that shock.

When an injury occurs, for Rodgers it was a calf muscle strain and for Romo an abrasion and contusion to the knee, the pain causes the muscles to be unable to move the joints at the same speed or power, and the body reacts by changing the timing on the affect side. When walking, there is more time for both legs to be on the ground and the ability to mitigate the forces generated by the stride. With increased speed, each leg has to increasingly independently deal with the shock of landing. If an injury occurs, the body compensates by spending less time on the affected side, shortening the stride length, and decreasing the time of the swing phase so that both feet spend more time on the ground to support the body. This is the cause of the limp. Pain equals protection to the brain.

Walking and running are complicated and require a variety of muscle groups rotate, accelerate, and decelerate the joints involved in the movement. The body’s center of mass has to be supported throughout the weight bearing movement and this requires the pelvis to rotate and tilt, the knees to flex in coordination with ankle and foot movement and then reverse the motion to complete a gait cycle. If the mass is not supported throughout the gait cycle, the body falls down. An injured person walks with an antalgic gait (ant=anti +algic=pain). The limp protects the injured side from supporting the weight of the body for longer than it has to. If there is too significant injury that causes too severe pain, attempts at weight bearing fail and the leg buckles, the injured person stops moving or falls.

Understanding the mechanism of injury, knowing the anatomy and observing the limp, a trainer, physical therapist, doctor or chiropractor can watch a player’s gait may get a sense of injury location and help with an on-the-sideline temporary fix or decide that the injury is too severe to continue. That decision has a lot to do with the ability of the body to protect itself from further harm. On the football field that might mean evading a blitzing linebacker but for the home athlete, it might mean the ability to prevent falls around the house. Limping is never normal and it emphasizes the body’s protective mechanism. Without the limp, the body’s weight spends more time being supported on the injured side and the risk of falling increases. Falling is never good. As the body gets older it tends to break, not bounce and the risk of secondary injury increases.

With the loss to Green Bay, Tony Romo’s season is over and he has ample time to heal his wounds. With but seven days, the Packers’ Rodgers does not have that luxury. He may have the mental strength to try to overcome his injury and try to push his body to play hard, but in the end, he will be limited by physiology. Eve

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3 Responses to limping

  1. […] I’m a nerdest and love everything medicine and science, I enjoyed this from MD Direct on the mechanics behind the limp of Aaron […]

  2. […] I’m a nerdest and love everything medicine and science, I enjoyed this from MD Direct on the mechanics behind the limp of Aaron […]

  3. Rodolfo Gonzalez says:

    What about nerve damage on the Lumbar Spine. Is surgery is going to fix it?

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