Squash Injury At It's Base
April 13th will mark the 1,200th day of my run streak, and I really have no interest in stopping. As you can imagine, to maintain daily consecutive runs, I have had to take injury prevention quite seriously. As a personal trainer, I have also taken every chance I can to soak up learning opportunities so I am able to pass down my knowledge and experience to my awesome clients.
I have had my share of injuries from falling off a curve to tripping over a pet. Clumsy and klutzy happenings that have gotten in the way of running goals, but not exactly what I want to address at the moment. As a runner, it’s important to be flexible, balanced, and agile so that when Fluffy does get underfoot, we are able to compensate without ruining our weekly mileage. However, all other running injuries, at their core, come from some form of overuse.
To be clear as a term, the word “overuse” must be understood as repetitive stress. As it is applied to exercise and fitness, repetitive micro trauma stimulates a repair cycle that leads to muscle growth, strength, and athletic improvement. In order to facilitate this repair cycle, we must tax our bodies, and then proceed to get enough rest from the specific activity, carve out 7-9 hours for sleep, stay hydrated, and combat oxidative stress with rock solid nutrition (link here for my go-to). So, in general and when balanced with other healthy habits, the micro trauma we cause in exercise is a good thing until it exceeds the repair cycle. Even while safe-guarding your body through rest and nutrition, repetitive stress is likely to win out while running, dancing, even walking for fitness if we don’t understand it properly.
The reason repetitive stress seems to be winning out with impact activity begins with the forces of impact, and our loading response. Ground reaction forces on a runner exceed four times our body weight into that one leg we are landing on with each stride. For walking, the force is as high as two times greater, which is certainly easier, but just as concerning in a deconditioned body. Dancing is even more complicated because body weight is not always spread evenly on the surface of the footbed. Racquet and team sports include the impact of running, and also the unpredictable nature of how the foot connects to the surface with each movement.
So, how is there any hope for us fitness warriors? Luckily, the human body is very good at adaptation. You can, over time, train your body to take the impact. In this respect, it is important to slowly build up your milage running or walking, and to slowly build up your time spent dancing and doing other impact activities as well. The general rule of a 10% or less milage increase is a great place to start. Consider this for other impact activities as well, most appropriately adapting for the amount of time you are participating. For instance, if you normally go to a one hour Zumba class twice a week, jumping in and doing a full 3 hour special event should be considered with caution! The equivalent would be someone who jogs 5 miles, twice a week, and suddenly gets up to race a half marathon for a personal record. Crazy, right?
Let’s dig a little deeper into understanding why this is so important, and learn about a few other things we can do. There are four major types of mechanoreceptor cells in our skin. I don’t mean to sound too complicated, so think of the words, “mechanical” and “receptors,” and now you realize we are basically talking about working parts that are responding to stimuli. These mechanoreceptors are nerve endings in the skin that function on the sensations of skin stretch, texture, light, and vibration. Of greatest relevance to impact forces, are the Pacinian corpuscles, which respond to sudden disturbances of deep pressure and vibration. Through their ability to detect vibration, they are able to tell us about the surface we are landing on and help us maintain our balance.
The great thing about our Pacinian corpuscles is that they help our muscles deal with what we do to them. Our soft tissue isn’t so interested in vibration and badly wants it to stop. Once the Pacinian corpuscles perceive the impact, our muscles are signaled to make an isometric contraction in order to halt the vibration. There is even an intra-muscular pressure that is compartmentalized by various groups of muscles as they are surrounded by fascia. Envision that lean, defined calf muscle in action and you get the idea. It is this isometric contraction that protects our joints and ligaments. Consider as if you are about to be punched in the stomach. In order to dampen the impact, you brace yourself by contracting your abdominal muscles. This intra-abdominal pressure is an isometric contraction of your muscles that provides you with greater stability and protection of your inner organs and your back. In return your assailant feels the potential elastic energy in his fist and is impressed by your fearful strength. In running, the elastic energy of this compartmentalized muscular contraction results in a catapult effect, much the way a kangaroo loads and reloads as it bounds through the Outback. The ligaments are saved, the joint is graced with full mobility, the muscle feels alive, and there you are bounding along with the kangaroo into the the sunset.
If we want to keep bounding across the Outback, the key to our success is anticipating the impact force properly so that our muscles continue to dampen the load put upon our joints and ligaments. As many of us know, if our ligaments are ripped to shreds, or our joints lose mobility, our activity is toast. So what do we need to do?
1. Work on balance. Being able to maintain balance while participating in activities will help us maintain control of the loading response. You can work on your balance in any number of ways. I honestly suggest to behave more like a child. Step up on funny things, pretend a curb is a glance beam, hop around on one foot, jump rope. Work up to this slowly because, as much as you may feel like one, you are not actually a child, and probably haven’t done this in a while.
2. Focus on single leg exercises. In oder to improve our relationship with the impact forces from our activity we need to prepare ourselves with single leg strength. Single legged squats (or pistol squats) are a great start. They are challenging and may require a hand on a chair for assistance at first. Single leg floor taps are also fabulous, and work on many muscle imbalances. Place a few cups in a semi circle about 18 inches away from your standing foot and bend down to touch each one while maintaining balance on one leg. A third simple exercise is a rotational lunge. Stand facing forward, and rotate to your side as you lunge in that direction. Aim to do 3 sets of 10 reps of each, on each side, with each of these exercises. In the gym, be sure to ask your trainer (for many of you that’s me) for single leg acceleration and deceleration exercises in order to build power into these skills.
3. Become aware of your footbed! In addition to the foot massage you should already be doing manually or with a golf ball, try this simple exercise before activity. With a bare feet, stand one foot slightly in front of the other and put most of your weight into that front foot. Now, spread the toes of your front foot and push the big toe into the ground. The other toes will follow and squish into the floor too. This should cause your arch to engage and raise up slightly. Hold for 10 seconds and repeat on each foot 3-5 times. This exercise will awaken the fascia on the bottom of your foot and help the Pacinian corpuscles do their job.
4. Build slowly. Muscle fatigue will cause delay in responding to the impact forces of our activity through compartmentalized muscle contraction. Along these lines, you can offset fatigue by getting enough rest to decrease the inflammatory cycle, and by wearing compression sleeves during activity. Compression sleeves give just that little bit of extra support, mimicking the compartmental pressure of your muscles. I have found compression particularly helpful on long runs. As you slowly build muscular endurance for your activity, your ability to quickly and efficiently contract your muscles over a longer period of time will also increase. The key is giving your body time to build this endurance. Be patient and increase slowly.
5. Develop stretching and self myofascial release habits. Myofascial release can include deep massage, foam rolling, and cupping (link), and should be performed only post-exercise. Warming up properly, light dynamic stretches, and self massage all keep our muscles limber and rid our muscles of lactic acid build up. Acidic conditions delay muscle contraction. If we compromise the rate at which our muscles can create compartmental pressure, that isometric contraction that protects our connective tissue and joints, than we risk injury. Inflammation from exercise causes tissue to weaken, and as they repair, that scar tissue needs to be brought back to elasticity through myofascial release. Our potential energy lies in the level of fascial flexibility we are able to maintain. Our rested, limber muscles in alkaline state (rid from lactic acid) are stronger, resist fatigue, and allow for optimal joint mobility. Working on your own body will also make you more aware of what it going on so that you can make better decisions while engaging in your activity. For instance, if you find you are having a hard time working out the tightness in your thighs, go easy on the downhill. Your quadriceps are the muscles in charge of halting the vibration in downhill running, so if they haven’t recovered as well as the rest of you from your last effort, don’t risk injury by bombing the hill.
6. Consider factors within your control. Sleep, hydration, nutrition, body weight. What’s more is a hypothesis by Dr. Benno Nigg called Muscle Tuning. The applicable idea is that our bodies must anticipate an accurate frequency of vibration from the impact in order to have the proper impact response and stay injury free. Switching run surfaces, having too much cushion in our shoes, and having too long a stride length can all get in the way of our body’s ability to adjust to the loading response. In other words, Niggs believes that our Pacinian corpuscles are firing in ever so slight anticipation of our impact. By wearing cushioned shoes, orthotics, and developing other running technologies, we are getting in our own way by preventing our optimal sensation of the surface. While footwear and minimal running is a touchy subject, it’s worth an understanding. I ran in barefoot shoes for years and would be happy to discuss it’s pros and cons more at another time. For now, If you are going to “go barefoot,” I strongly recommend you do so very slowly and make your own assessment about how it works for you. In the meantime, it is helpful to focus on one running surface at time. If you run to the trail from your house, perhaps a loved one can pick you up so you don’t have to switch back to the hard pavement on the way back. It is optimal to stick to only one surface per run, and soft surfaces are more kind. Finally, by all means, hone in on your stride length. A shorter stride will keep the angle of ankle dorsiflexion less dramatic and minimize impact. As many of us have poor dorsiflexion, and poor calf flexibility, minimizing ankle fatigue is important to consider (as well as improving flexibility in the ankle and calf). Start by recognizing your cadence. Right around 180 steps per minute is a good target. It is really hard to take too big of a stride with such quick feet. You may even find yourself running a little faster!
I hope that I have helped you understand the basis of repetitive stress injuries in impact activities. After all, our base is right here at our feet. If we only considered what happens when our feet first touch the ground a little more, we might not see the volume of running injuries that we do. Impact is actually a wonderful thing. Since the close of the 19th century we have had the benefit of understanding Wolff’s Law of bone modeling which tells us that the reparative cycle resulting from the stress of load bearing activity improves our bone density. By all means do not give up impact activity! Instead, use these guidelines to work on your own proprioception to be a more efficient runner. In other words, get better at sensing the ground. Each morning we get out of bed and our feet are the first thing that hit the floor. This is our single most important daily activity. It is the starting point for all of that great potential we have each day to make a difference (motivational speech!), and it reminds us, literally grounds us, as to where it all begins. Happy running.
Photo of me at mile 18 of the NYC marathon. My face tells the story. I went into that race with a hamstring injury and managed to keep pace only until right around the time my friend Lee snapped the pic. More noticeable than the pain in my hamstring at the time was that my joints lost all reasonable range of motion. I did try to keep a smile!
