Have you ever wondered why the Gastrocnemius (calf muscle) and Hamstring muscles insert on BOTH sides of the femur (upper leg bone) and tibia (lower leg bone), respectively? If they purely functioned in one plane by flexing the ankle and the knee, we would have the insertions most likely smack in the middle of the femur or tibia. However, we do not, and thus, there must be a reason why there are two insertions medially and laterally. The answer is that all muscles function in three dimensions. And physical therapists Gary Gray and Gray Cook's answer to three dimensional muscle activity is to develop dynamic functional assessments and screening.
I've discovered a fabulous Physiotherapy clinic in England called Physical Solutions. They have created a great clinic by which I have been trying to model my own clinic. Physical Solutions is unique in that they have combined the works of Gary Gray, PT and Gray Cook, PT to create a super duper FUNCTIONAL assessment system called Dynamic Movement Screens.
In the past, sports medicine practitioners have evaluated the body by watching it perform in a single plane and usually one or two joints at a time. For example, they would test how far you can touch your toes, test range of motion of each joint, or test the strength of a muscle while you are lying on your back or side. While this can give you a preliminary assessment of a particular joint, it doesn't tell you 1) how your joints, muscles, and nerves work TOGETHER to accomplish a particular task, and 2) whether or not the normal findings in flexibility are stable in a dynamic movement such as sport. We can have the flexibility, but we may be unable to use that full range of motion because our body hasn't figured out a way to stabilize the movement in that range of motion.
For example, a female runner may have plenty of hip extension (leg moving back behind the body such as in the push-off in running), but if she doesn't have adequate lumbar spine and pelvic stability, the leg has little foundation to extend from and therefore, performance is not optimal and/or she can develop back, hip, or leg pain. Or she may have poor foot and ankle stability and thus her body has to work extra hard in the hip to "make-up" for the lack of stability in the ankle and foot. Sooner or later, the hip won't be able to take on the extra effort and thus may become injured.
Thus, Physical Solutions has determined that the body knows only movement patterns, not which muscles are activating when. We can analyze the body by breaking down movement PATTERNS that are fundamental in everyday life and sport. This way, we can assess asymmetries, imbalances, and instability that cause poor performance and/or chronic and acute injuries. All movement screens are assessed in a gravity environment since our bodies have to control and coordinate itself due to gravity reactions and forces as well as ground reactions (for every action, there is a reaction, etc.) Thus, we don't assess Gluteus Medius (a lateral hip mover and big pelvic stabilizer) in a lying down position and in isolation because the Gluteus Medius is often "turned" on to stabilize the pelvis by the ground reaction of the foot and ankle. One can have a VERY strong Gluteus Medius side lying, but demonstrate poor activation in a single leg squat.
Here's what I have learned over the past several years about assessing biomechanics and movement:
1) We move in reaction to gravity. We often overlook the fact that our muscles and tendons have to CONTROl movement against gravity. We accomplish this by an eccentric contraction of our muscles and the stored elastic energy of our tendons. For example: The achilles tendon decelerates the tibia (lower leg) moving forward towards the ground while running. Meanwhile the posterior tibialis muscle decelerates the arch in the foot from overpronating. If the posterior tibialis doesn't do it's job, the achilles tendon may become overworked by having to control excessive side to side movement due to the arch overpronating.
2)All muscles in our body perform in all three planes of movement- forward and back, side to side, and rotation, thus we must assess movements in all three planes. We also must give exercises in all three planes. We often find a patient may be able to perform a task successfully in two planes, but not in the third plane. Thus, the body will compensate for that lack of movement in third plane by moving TOO MUCH in one or both of the other planes. This can easily lead to injury as the muscles or tendons can become overloaded.
I believe the Dynamic Movement Screens are an essential way to assess biomechanics in sports medicine. Fortunately, Gary Gray has been on the forefront of research in this area. Hopefully, his research will be discovered by more and more Sports Medicine practitioners here in the states and there will be an influx in functional assessment for athletes.
Here at Innersport, we use Physical Solution's Dynamic Movement Screens in addition to videotaping of your gait and cycling to learn more about the weak links and kinetic chain dysfunctions leading to poor performance and chronic injuries. Stay tuned as we will have a whole new business (Press Play Analysis coming soon) entirely dedicated to Videotaping Dynamic Movement Screens and gait and cycling available to local, Bay Area athletes. Look for us in Berkeley (currently taking clients), San Anselmo, and Lafayette in the near future.