Pain During Activity and Sports
The first and most obvious way in which pathokinematics can affect performance is the fact that certain kinds of pathokinematics lead to injury over time. Injury often brings pain, and even when an athlete is ready to return to sports activities, he or she may have recurring pain with the activities that directly or indirectly involve the body part that was injured. Additionally, he or she might have pain when involved in activities where the movement patterns are the same as when the injury occurred, since those movement patterns were likely to have contributed to the injury in the first place.
Let’s look at a specific example. The human body is designed to function in a given way as we have discussed previously. When we allow our bodies to operate outside the “norm,” movement becomes less efficient, requires more energy, and can result in tissue break down and injury over time. To illustrate this point, let’s look at the human gait, which is the way we walk.
First, the heel strikes or contacts the ground with the foot slightly supinated and then the foot pronates to the point of mid-stance, at which time all of the weight of the body is centered over the foot. Next is the “toe off” in which the foot continues to pronate to allow push off on the 1st ray (big toe). The foot, ankle, knee, hip and spine all work together in harmony during each of these defined phases in order to facilitate forward (in this example) movement of the body while in a standing, upright position. These structures have certain ranges of motion specifically designed to allow our joints, ligaments, tendons and muscles to absorb the force of these actions in ways that are not detrimental to the structures themselves over time and with repetition.
An athlete (or walker as in the example above) with excessive tightness of the hip flexors (iliospoas) This has two effects. First there is a decrease in the extension of the hip which causes a decrease in stride length. A decrease in stride length which means a shorter stride, less distance covered per stride and less force is produced and force absorbed. Because the stride is shorter and less distance is covered for every foot strike, this means performance is impacted. Since there is less absorption of ground reaction forces in the lower limb, this means greater risk for injury. Less force absorbed in the lower limb means that force (which does not change) is absorbed further up the chain or in the sacral and lumbar spine. This pattern of decreased hip extension is often associated with a compensatory increase in spinal extension and rotation in the lumbar spine. When this occurs, we can observe several motions at the hip. Excessive rotation (transverse plane motion) and excessive anterior and posterior tilt (sagittal plane motion) can be observed at toe off on the side where there is a decrease in stride length. The result of this type of motion in the transverse plane is excessive shear wear on the articular surfaces in the lumbar spine, especially in the areas of the L5/S1 vertebrae. It is well documented that articular cartilage is weakest when subjected to shearing forces and therefore this can be a source of lower back pain for runners and walkers. This lack of hip extension can also lead to weakness of the gluteus maximus on the involved side. As a powerful hip extensor, if the hip does not go into full extension, then this muscle can not achieve its maximal strength potential.
Weakness in the gluteus medius muscle of the hip can further contribute to lower back pain in this population because weakness in this muscle can lead to excessive hip motion in the coronal plane (side to side and up and down). So in the example above we can see a direct link between pathokinematic movement (excessive hip motion in both the transverse, sagittal and coronal planes) in runners and walkers that can lead to pain (lower back in this case), which exponentially increases the likelihood of decreased performance. Obviously, the greater degree of pathokinematics we see in an athlete, the greater the likelihood of more significant amounts, degrees and durations of pain, particularly during times when speed and/or endurance requirements are high.
Estimates are that 80% of the population suffers from one form or another of low back pain and consequently this type of problem affects many athletes and decreases their ability to perform. The most common area for low back pain is in the region of the intervertebral disc at L5/S1, which is often caused by wear directly attributable to pathokinematic movement in the lumbar spine and hip seen in runners and walkers. So, whether it is the ability of an athlete to sustain speeds and run long distances without pain or the ability of an athlete to get into and stay in the aero position on a bicycle, low back pain will dramatically impact performance. Of course, it is obvious that low back pain would also be a limiter in lifting sports, bending sports or sports that require full body speed and agility, such as basketball and volleyball. A particularly notable sport in which athletes often complain of lower back pain is golf. Often when looking at a golf swing, we see tightness in the hip flexor muscles that cause lower back issues over time.
For a good dynamic hip flexor stretch, try this stretch to help prevent lack of hip extension.