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Principles of Running by Dr. Mark Cucuzzella


A excellent video on the principles of running from a biomechanical perspective. If you are a runner you need to spend the eight minutes to watch this video. Enjoy!!!


Jeff Moreno, DPT, OCS

Precision Sports Performance




 "Remember the feeling you get from a good run is far better than the feeling you get from sitting around wishing you were running." –Unknown

       Have you ever wondered what really happens when your foot hits the ground while you run? The purpose of this article is to define the three primary phase of running, and describe in detail the loading phase of running.  In addition, this article will explain how the phases of running can relate to efficiency or potential injury and lost training time.

        Let us take a few minutes and review the last article, “Posture & the Secret of Running”. In my previous article I discussed passive and active posture, and how it can help prevent injury and increase efficiency. Good standing posture is the straight vertical alignment of your body from the top of your head, through your body’s center, down through the middle of your feet. From a side view, good posture is seen as an imaginary vertical line through the ear, shoulder, hip, knee, and ankle. This posture will result in the center of mass (COM) being directly over the foot/base of support (BOS) allowing your weight to be evenlydistributedthroughout the whole foot. Remember, the secret of running is the unique ability to control, unconsciously, your center of mass (COM) in relation to your base of support (BOS)/foot. Good static and dynamic posture is one that allows you to be more aware of where your body is in space. Being proprioceptively aware of your body and its relationship to your foot/BOS and the ground is essential for your ability to load, unload, and recovery properly.

        Running is nothing but a series of single leg hops. These hops result in the transfer of energy from your body to the ground allowing for forward progression. The pace of the runner is dictated by the amount of energy transferred. When biomechanically efficient, the body is able to get from one point to another expending the least amount of energy over a given period of time. When running, the focus should not be on running faster or longer, but how to become more biomechanically efficient.  The goal is to expend the least amount of energy over a given time, speed, or distance. This will result in faster times if so desired, but more importantly it will allow for improved motor programs (better habits) enabling the runner to train uninterrupted and more efficiently.

       In order to understand what the three phases of running are you need to first understand that the body works as a whole and never in isolation. With that said, scientists and coaches have separated the phases of running in order to better understand and conceptualize.  I am going to define what the three phase of running are, with emphasis on the loading phase.

The three phases of running are the loading phase, propulsion phase, and recovery phase (see pictures below). It is essential to understand that the running cycle is cyclical. Therefore, each phase is dependent on one another. For example, if your loading phase is poor you will not be able to achieve a biomechanically efficient propulsion phase, which will inevitably reduce the passive nature of your recovery phase, making you work harder and less efficiently.

Right Loading Phase  

 Right Propulsion Phase (End)

 Left Recovery Phase

       The loading phase starts (see pictures below) when the foot hits the ground. Contrary to popular belief, the foot should make primary contact in the mid-foot or forefoot and not the heel (hind-foot). Making contact primarily in the hind-foot allows for significant braking forces, reduced elastic energy storage, and longer ground contact times which can lead to a number of different injuries. Landing on the outside of the foot is usually not felt but is essential, biomechanically, for the foot to be loaded. This helps the transfer of weight from the outside of the foot to the big toe. This transfer of weight allows for the foot to passively lock-up, creating a natural rigid lever to push off of in the propulsion phase of running.

Beginning of the Loading Phase

       When making contact with the ground, the lower leg from the knee down, should ideally be perpendicular to the ground, this results in the ankle joint being neutral, setting up the calf and Achilles tendon to be loaded for a recoil effect. The recoil effect can be easily understood by taking a rubber band, stretching it, then letting it go. The energy that is created by stretching the rubber band is given relatively for free, it just needs to be taken advantage of.  We call this, in the scientific community, a stretch reflex. At loading, (initial contact) if the heel is off the ground or the foot is taken off the ground too fast, the “free energy” that is given by the calf-Achilles complex (rubber band effect) will be forfeited. This will ultimately lead to more work and inefficiency. I call the calf the “pseudo butt/hip” because it will try to work and act as the hip if you ask it too. Unfortunately this can lead to overstriding, reduced force production, potential calf strains, Achilles tendinopathies, and dysfunction up the chain (leg).

       The knee, when making contact with the ground, should be bent (approximately 20-25 degrees), and the lower leg be perpendicular to the ground allowing for the body’s center of mass to be oriented slightly behind the base of support (foot). It is important to understand that the foot is not where power is generated from; it is only the last point at which energy/force is transferred to the ground. Therefore, you do not want to take the foot off early or land completely on the forefoot, for it is when the foot is on the ground that the transfer of force takes place. Increase in speed is only a result of a faster transfer of energy, not because of the foot lifting off the ground earlier or getting quick with the foot. When the lower leg has completely “loaded up”, shock absorbed, then you begin the propulsion phase or the push phase.

       The loading phase is the phase where most individuals are dysfunctional, contributing to pain and injury. What makes this phase the source of runners pain is the high loading force when we hit the ground. Those forces if not attenuated appropriately can increase stress and ultimately pain at the foot, knee, hip, and/or lumbar spine depending on the runner. For example, let us take a look at two runners that overstride (see pictures below). As you can see on the pictures, these two runners are about to hit the ground with their heels first and with their knees completely extended. With the knees extended, they are reducing their ability to absorb shock as they make contact with the ground. Overstriding reduces the spring/recoil effect that passively generates force. The result will be a significant increase in force at the knee, which can contribute to eventual knee pain. More importantly, this increases the demand at the quadriceps muscles and reduces the hips ability to push them forward resulting in a poor propulsion phase and a more active recovery phase.



       Then how do we correct overstriding? Remember, that what you see is usually a symptom of some other problem. Therefore, correcting ones overstride is more complicated than just asking them to reduce their stride length or pull their foot underneath them when they land. Some examples that can cause overstriding include; flat lumbar spine (flexed lumbar spine), posterior center of mass, forward shoulders with thoracic kyphosis, weak butt (gluteals), poor motor control, and dominant quadriceps/plantarflexors. The trick is figuring out what is facilitating overstriding, and treat the cause not the symptom. That is not to say that I won’t address the obvious symptom if necessary. With that said it is really hard to diagnosis and treat the cause of a poor loading phase on your own.  If you are suffering from pain or dysfunction, try to find a running specialist in your area in order to be properly evaluated and diagnosed, so that you can start the road to recovery.

       Next, in the “How to Run” series, I am going to try and answer whether or not it is ok to land in your heel. I get this question almost daily and it is more complicated than answering with a simple yes or no. I also want to know from you as runners, what do you want to know more about running? 

Key Points:

  • Work on standing with your weight evenly distributed throughout your feet.
  • Know what your static posture is and correct it if necessary.
  • Standing Posture=Walking Posture=Running Posture
  • See if you can tell what part of the foot are you primarily hitting the ground with? Heel or Mid-foot       
  • Are you having pain consistently, if so you may be loading improperly and could benefit from a running evaluation?



?"The will to win means nothing if you haven't the will to prepare."?? - Juma Ikangaa, 1989 NYC Marathon winner

??????? Have you ever looked at a runner and asked yourself, how do they make running look so easy? What secrets about running do they know that I don

How To Run: Bad Habits That Hurt

Have you ever asked yourself why a runner can run just as fast, just as long, and with the same effort and ability as the next runner, and still end up with knee pain?  What if the strength gains made due to running/training are ultimately what results in injury and loss of training time? What if you’re running form is causing the development of dysfunctional patterns of movement, increasing your potential for injury?

The human body will always compromise quality of movement over quantity of movement. If you ask your body to run a specific distance at a desired speed it will do so with what it has regarding range of motion, strength, and neuromuscular control. However, it may not be the most optimal and biomechanically efficient way. The human body is uniquely adaptable to any physical stress that is placed upon it. Runners cherish this principle of general adaptation, which enables them to improve their basic endurance and general strength over a given time. With this in mind, whether a novice or elite runner, the groups of muscles that are used on a daily basis with normal daily activities are the same muscles used in the act of running. We, in the scientific world, call those patterns of movement, motor programs. A motor program is analogous to a habit that is unconscious. Those habits (motor programs) can prevent or create pain and dysfunction.  If you use those sets of muscle incorrectly during your daily activities, those motor programs will carry over into your running.  So if knee pain is your symptom, you have to understand the root cause of that pain is likely an abnormal motor program that needs to be adjusted or tweaked, not just in your running but also in your daily activities.

Let’s look at a runner with knee pain. The motor program that this runner has in his normal daily activities may allow for them to stand with their weight in their heels and lock their knees out. This increases the use of their thigh muscles and turns off their hip muscles. During running this motor program causes them to have (remember this is all unconscious) their center of mass behind their foot, and results in them straightening their knee too much as their foot is coming toward the ground forcing them to over stride. Over striding increases the force of impact, reducing the knees ability to act as a natural shock absorber. This leads to increases in stress and overuse at the knee.

Another example would be a runner who has iliotibial band syndrome (IT Band) that has developed during training for a marathon. This type of runner commonly stands and walks with their foot turned out and is usually very strong in their quads, lateral hamstrings, and calves. This runner takes that posture and strength into their training and overtime those muscles that are already strong get stronger due to the body’s general adaptation to training. As a result, this runner begins to over extend their knee, which forces their foot to be too far in front of their center of mass. Therefore, the body has to pull the runner forward by overusing their quads and lateral hamstring which rotates the lower leg out relative to thigh and shortens the IT Band. Because of the runners’ form and dominance of the quad and lateral hamstring muscles, they begin to develop pain at the outside of the knee. The pain on the outside of the knee occurs as their foot comes off the ground and their leg begins to cycle back through.

Remember, the body will always do what you ask of it.  Whatever has been “asked” of it during daily activities, with respect to strength, range of motion, and motor control will transfer over into the act of running. These motor programs, if not correct, will inevitably lead to musculoskeletal injury and lost training time. Therefore, the next time you stand and walk, think about how your posture is creating patterns of movement and muscle activation that will be accentuated in your running.   

Next in the “How to Run” series I will be discussing the secret of running, and how static standing dictates how we walk, which dictates how we run. If you have any questions regarding running and/or the above discussion, please feel free to email me. I love to discuss and debate anything related to running.

Enjoy the Process!


Jeff Moreno, DPT, OCS

Precision Running and Performance Clinic

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