By Dr. Aaron Case BSc, DC (February 2007)
Have you ever noticed runners twisting their legs, hips, and upper bodies; running on eggshells; or allowing their arms to swirl like eggbeaters?
The running styles described above occur when our shock absorbing muscles are not fully utilized. Without our main shock absorbers there is a tendency to twist our bodies and change our running form to avoid further impact and irritation around and between the ankle, knee, hip, and lower back. When our body transfers the impact from our shock absorbers to other parts of our body, this can also make you feel like the location of an injury/ache/pain has moved. In reality, the forces have just been shifted temporarily and this will only delay or change the location of an impending injury.
Shock absorbers: joint actions, major muscles involved and examples of potential injuries when these muscles and joints are overtrained/strained:
- Ankle (dorsi) flexion: Calf muscles (gastrocnemius and soleus).
Potential injuries include: Plantar fasciitis, Achilles tendonitis, calf tear. - Knee flexion: thigh muscles—quadriceps.
Potential injuries include: Runner’s knee (PFPS), iliotibial band friction syndrome (ITBFS). - Hip flexion: butt muscles—gluteus maximus.
Potential injuries include: Piriformis syndrome, hamstring strain.
Therefore, to optimize shock absorption, you need to focus on two different aspects of running technique and training:
- Foot strike
- Running simulation training: Eccentric muscle contraction, closed chain, speed of contraction
Foot strike
For distance running, the forces of initial impact should land as closely beneath the centre of gravity as possible i.e. directly underneath your hip. By not landing ahead of the centre of gravity, breaking forces are reduced. Also, like a pogo stick or steel spring, vertical forces created by landing underneath the hip allow for optimal shock absorption through the ankle (calf muscles), knee (quadriceps) and hip (gluteal muscles). When all of these joints flex simultaneously, they are more likely to recoil synergistically for optimal power generation.
Running simulation training: Eccentric muscle contraction, closed chain, speed of contraction
To translate exercises that dominate most fitness routines and cross-training activities (cycling, weighted gym exercises) into running improvement, try eccentric exercises (muscle lengthening under force). A good place to start is the partial drop squat. During this exercise, all of the major shock absorption muscles (mentioned above) are forced to contract eccentrically (while lengthening) around the ankle, knee, and hip simultaneously.
Partial drop squats should progress from slow lowering of the body with both legs (several seconds down, a couple seconds up) and progress to twenty to thirty single-leg quick drops into the quarter squat position. During this exercise, try to keep your knee over your second toe and keep the knee from advancing beyond the length of the foot. Be sure to progress slowly as this form of eccentric training typically leads to increased soreness and recovery time.
Summary
So the next time you look at your reflection in the store window as you run past, realize that you can more effectively train your shock-absorbing muscles to improve your form, prevent injury, and even run faster if you put your egg beating arms back in the bowl where they belong.
