LOWER EXTREMITY INJURY PREVENTION AND REHABILITATION (PART 1)

Part 1:  Injury Prevention

Lower extremity injuries have an incredibly high prevalence in sports.  Unfortunately, the occurrence of these injuries has already become intertwined with athletic culture.  Lower extremity stress fractures alone represent 1-20% of all sports medicine injuries with the most common stress fracture site being the tibia at 23.6%.¹ This is no surprise given that the tibia is the main weight bearing bone in the lower leg. The one upside to all these injuries, is that researchers have taken a special interest in early identification, better rehabilitation, and most importantly, injury prevention.  My hope is that this blog will give you the tools to help you achieve a better understanding of these injuries and an idea of what tools you already possess to help prevent injuries from occurring.

The primary strategies I have found to be effective in decreasing a person’s risk for lower extremity injuries are:

1.    Strength Training with Deceleration

2.    Eccentric and Isometric Training

These strategies are currently being studied in clinical research for their effectiveness, and I have clinically seen the evidence of their efficacy.

Disclosure Statement: Keep in mind that every injury and individual is different.  What may work for one individual, may not work for another. If you ever suspect that you are experiencing any of the injuries discussed in this blog post, I fully recommend that you seek out a skilled medical help.

1. Strength Training with Deceleration:

Deceleration, or negative acceleration, is the act of exponentially decreasing speed.  This movement is a component of physical control and often is characteristic of athletes that quickly adapt to changing circumstances on the field or court.  The logic behind strength training deceleration to decrease injuries is simple. Acute and chronic lower extremity injuries are associated with a mechanism of the injury.  If these injury mechanisms are altered and strengthened, the chance of injury can be decreased. In this case, the injury mechanism being addressed is uncontrollable movements by an athlete.  For example, let’s say a male soccer athlete is attempting to avoid a defender. In his attempt, he rapidly changes directions cutting left even though his initial direction was right. Before the change of motion occurs and the athlete is able to rapidly accelerate to the left, one thing needs to happen: deceleration.  The athlete must decelerate to the right first before accelerating to the left. Think of an athlete jumping as high as they can, like a basketball player going up for a rebound. All of the force that got put into the height of the jump has to come back down. We need to teach our bodies how to properly land and disperse that force evenly back into the ground. If this mechanism is performed incorrectly, injury can occur.  Now, what if the athlete has poor technique with his deceleration, or has simply never been taught proper mechanics of deceleration. Every time that athlete changes direction, or decelerates, he is putting an increased and unnecessary mechanical stress on his body that over time, or even in the blink of an eye, can lead to injury.

Now, what are proper strength training deceleration techniques and exercises that can help prevent this from happening? Here are two exercise examples that focus on deceleration mechanics. 

1.  Drop Squat to Stick

Let's start with the Drop Squat to Stick. This exercise is one of the first exercises that we teach in the deceleration mechanics progression series. The focus of this exercise is to create an upward force and then control the force as it shifts down toward the ground. This helps prepare the body to land and properly absorb the force.

Here are 5 main coaching cues we use for the Drop Squat to Stick:

1. Get as tall as you can reaching your hands overhead on your toes.

2. Bring that upward force back down to the ground.

3. Simultaneously, lower your arms and bring your toes just slightly off the ground.

4. Feet land flat and absorb the impact.

5. Arms follow through past your side as you land.

     *Technique Tip: keep your knees pointed forward, do not allow them to shift inward.

2. Skater Hop with Stick

A more advanced exercise in our deceleration mechanics series is the Skater Hop to Stick. Here, we are getting outside of the sagittal plane that we mainly move in and transferring to the frontal plane. In other words, we are used to moving forward, but this exercise includes more lateral direction movements that we do not commonly practice. This is extremely important when it comes to deceleration during changes in direction.

Here are 5 of the main coaching cues that we use for the Skater Hop w/ Stick:

1. Load weight onto one foot.

2. The arm on the loaded side should be back, and the arm of the non-loaded side should be forward.

3. Explode off of the loaded side and transfer weight to the opposite side.

4. As you land, absorb the force and maintain your balance.

5. End with the arm on that landing side back and opposite arm forward.

     *Technique Tip: As you transfer your weight, switch the position of your arms.

2.Eccentric and Isometric Training:

The three primary muscle contractions that we know of are concentric, eccentric, and isometric.  A concentric muscle contraction occurs when a muscle producing force is shortening (the “up” phase in a bicep curl).  Eccentric contractions occur when a muscle is actively generating force to produce tension while the muscle is lengthening (the “down” phase in a bicep curl).  An isometric contraction occurs when a muscle is producing force, but neither shortening nor lengthening. So, why are eccentric and isometrics considered of greater importance when it comes to injury prevention?  Eccentric and isometric contractions create greater tensile load on both muscles and tendons. This tension helps mimic common mechanisms for acute and chronic injuries. Let’s go back to the example of a basketball player going up for a rebound.  This is a very common example of a mechanism for injury that occurs under maximal tension. As the basketball athlete comes back toward the ground, his calf muscles and achilles tendon have to control the lowering of his body. During this motion, the athlete’s muscles and tendons are producing an incredible amount of force, but the tissue is lengthening as he comes back to the ground.  This is a classic example of an eccentric contraction in practice, and is often when you see one of the most common injuries, muscle strains. By incorporating eccentric and isometric-focused exercises into your training regimen, you can help prepare your body for these high-risk injury scenarios and decrease your risk for injury.

Outside of an athletic event, what does eccentric and isometric training look like?  Here are two variations of a common exercise, the split squat, that focus on eccentric and isometric muscular contractions.

1. Split Squat w/ 5s Eccentric 

Coaching Cues:

1. Step back into a lunge position.

2. Keep chin tucked, core engaged, and a slight forward lean.

3. Without letting your forward knee shift inward, lower slow and controlled for 5s.

   1. Using the forward leg contract quad and raise yourself back to the top.

      *Technique Tip: At the lowest position, your back knee should be under your hips.

2. Split Squat Iso

Coaching Cues:

1. Step back into a lunge position.

2. Keep chin tucked, core engaged, and a slight forward lean.

3. Without letting the forward knee come inward, lower the back knee straight down.

   1. Once your back knee is 3-5 inches from the floor hold the position.

      *Technique Tip: Do not let your forward knee shift inward during the hold.

It is vitally important to remember that good exercises practiced without proper technique can help contribute to injuries and overuse.  Whether you are an athlete, parent, coach, researcher, or practitioner please be cognisant of form and technique. Technique should never be a casualty to volume.

I hope that this blog gave you some good takeaways into the importance of deceleration, eccentric, and isometric training for injury prevention. Use these strategies with proper progression to load the lower body during training.  Once you incorporate them into your strength training routine you will begin to reap the benefits of moving with more efficacy. Stay tuned for Part II.  

Resources:

1. Kahanov, Leamor et al. “Diagnosis, treatment, and rehabilitation of stress fractures in the lower extremity in runners.” Open access journal of sports medicinevol. 6 87-95. 27 Mar. 2015, doi:10.2147/OAJSM.S39512

2. Kravitz. “Rehabilitation Breakthroughs With Eccentric Training.” (2015). IDEA Fitness Journal, 12(2), 14–17.