Although the research and rehab community continues to grow our understanding of movement, some principles have stood the test of time. The relationships between muscle strength and joint position has been tried and tested. The same can be said with generating force from counter-movement. Luckily, you don’t need to know all the specifics… you just need to know us.
Although the following principles haven’t been tested for running specifically, I refuse hesitation for their application to run form and performance. Various articles tout the benefits of midfoot over heel strike running. Sure, some poorly designed, six subject research articles have challenged a strong foundation, but the evidence continues to support a soft, midfoot strike.
To what I’m aware these two principles have yet to be analyzed or researched as a means to support the use of a mid foot strike. The principles are real, tested, and proven. They define how muscles function and I’m simply applying the theories to the running movement.
The Length-Tension Relationship
At a tissue level our muscles are constructed of filaments known as actin and myosin. These filaments are what generate force and power as they ratchet on each other. The muscle can contract to shorten or lengthen, much like raising and lowering a bucket in a well. You’re likely waiting for me to link this back to running. Wait for it. First, you need to know that as your bones flex and extend your ability to generate force charts a bell curve. This isn’t earth shattering research; we’ve known this for a long time. Research conducted by Haffajee, Moritz, and Svantes1 in 1972 found that the position of your knee directly affects how much force the knee extensors can generate. This article, along with some preceding research, laid the framework and ideology of the muscle length-tension relationship. Muscles that are too short or too long cannot generate force, while mid-range is where the magic happens. Now, there are anatomical reasons for this, but far beyond the reach of this article. If you’re knee extensors (quadriceps) cannot generate force it’s safe to say they cannot store it either. Again, the previous statement is only applied, not proven (from what I can find).
Countermovement Force Generation
Although the research community is not settled on a ‘why’, we do know that our body can generate more force with counter-movement. An everyday example is observed when you jump. The counter-movement of lowering oneself prior to jumping stores energy within the muscle. A 1996 study conducted by Bobbert, Gerretsin, Litjens, et. al. found over 60% higher force production in study subjects when they utilized a counter-movement prior to jumping. The loading movement resulted in an average of height 3.2cm higher jump than those in a comparison group.2 We can apply counter-movement with every stride taken. As our body interacts from initial contact through midstance our center of mass lowers, storing force for push off. [see video below].
Why Do I Care?
Well, first your body is amazing–that’s why! Understanding how we function can help us better understand movement and sport. Leveraging research creates a faster, stronger, and less injury prone athlete. Haffajee, Moritz, and Svantes1 found that our knee is weakest at or near full extension. An extended knee negates the lever arm created from the patella. That, paired with a short quadriceps muscle, is a double whammy (my words, not theirs). Both factors effectively render your quad muscles useless. Wouldn’t you like your quadriceps absorbing force at landing and not your bones? I sure would. Second, we can observe counter-movement in every stride taken. Whether you heel strike or mid foot strike, you’re going to utilize counter-movement. The difference? A midfoot strike allows you to load sooner with less braking. You’ll take the force of push off and toss it into your next step and instantly counterload at contact. Think of it as carrying your momentum from stride to stride. Overstriding, which most runners do, creates a braking force that will negate any initial counter-movement. As gravity sends you back to earth you’ll be looking to store that force (through counter-movement) directly into your elastic tissues (ie. tendons and muscles) not your unforgiving bones. A midfoot strike offers this.
Landing midfoot has been long touted the ‘ideal’ way to run. Talks of minimizing braking forces and improved shock absorption have been beaten to death, revived, and beaten again. Some of you know you need to improve but are likely stubborn. Confiding within yourself, “This is the way I run and it’s ok” is selfish to not only your body, but your times. In a sport where injury run rampant (pun intended) and athletes spend countless seasons running the same splits and with the same injuries, learning and committing to a midfoot (not forefoot) landing can pay dividends. You may actually run faster without having to run more.
Commit to running faster and with less injury by learning a midfoot (not forefoot) strike. Our online members should master the following drills:
1. Haffajee D, Moritz U, Svantes G, Isometric Knee Extension Strength as a Function of Joint Angle, Muscle Length, and Motor Unit Activity. Acta orthop. Scandinav. 43,138-147,1972.
2. Bobbert MF, Gerritsen KG, Litjens MC, Van Soest AJ. Why is countermovement jump height greater than squat jump height? Med Sci Sports Exerc. 1996 Nov;28(11):1402-12.