Monday, May 21, 2012

When Power Leaks From the Feet

If you are like me, you've probably suffered an ankle sprain once or twice or three times in your life. Severe ankle sprains hurt, and they are often more painful than an actual bone fracture. With the rise of information coming out regarding ankle mobility, I began to wonder how can I help my clients prevent ankle sprains from reoccurring, while at the same time increase their ankle mobility? Years ago, I researched how the ankle joint--or more specifically--the metatarsal head of the foot; can effect vertical jump power. I was amazed at what I dug up. I began to look at my client's lower legs and what faulty joint kinematics I could find. I began noticing the same things:


a.) People that sat all day, had poor ankle mobility in the sagittal plane.

b.) Inactivity and excessive weight gain caused a displacement of weight on the ankle that may place them at a high risk for future ankle sprains.

c.) Pure strength was a crucial factor in balance training.

In the initial squat position of the jump, most athletes show an ankle(s) in a position of low bony stability (plantar flexion, inversion); the ligaments have a more significant role in providing joint stability and are more likely to be injured or produce weak propulsion (as in a jump). The first corrective step in preventing excessive mobility is to look at the peroneus longus (PL) muscle. The PL is arises from the upper 2/3 of the lateral surface of the fibula and inserts on the base of the first metatarsal (big toe). The PL and the role of other muscle-tendonius tissue create a “pulley effect” which enables the PL to act as a stabilizer for the first metatarsal during push-off by exerting a plantarflexion force. This assists in propulsion by creating a rigid lever for push-off.

During the vertical jump, electromyographic data confirm the role of the PL in stability and propulsion, as most of the PL activity is during the latter half of the initial stance phase. If the feet are excessively inverted or everted, the PL becomes inefficient in creating a plantarflexion movement and rigidity will not be formed during push-off. So the first step in improving vertical jump is assessing PL stability of the first metatarsal joint and observing propulsion stance.

One of the assessments I began using looked something like a typical calf raise. With insufficient stabilization from the PL, the first metatarsal head will lose contact with the ground; the foot will supinate, and the weight will shift to less the stable fourth and fifth metatarsal heads.

Fig. 1: Unstable metatarsals

Figure 1 shows what most therapists and coaches dismiss as a “conventional” supinated foot. The test is primarily a calf raise exercise initially performed bilaterally and progresses to being unilateral as stability improves. Most individuals exhibit supinated feet due to improper footwear which provide insufficient support.  Women that work in office environments are pressured to wear heeled shoes for 8-9 hours per day. For those that make it to the gym, will wear sneakers with high rubber soles. 

They look cool and are designed for running comfort, but they also pose a risk for most individuals to develop poor gait patterns early on. Without proper intervention, this leaves the problem to manifest and eventually affect sport or daily physical activity.

Fig. 2: Stable metatarsals

Thankfully with the popularity of flat soled sneakers and minimalist shoe wear, most active people can work on the lower leg muscles indirectly. As this is a double-edged sword, most of the general population should not run out to their local sneaker shop and purchase a pair of minimalist shoes without a proper assessment of the area; and a conditioning program to get these muscles up to speed. The problem facing most of the general population  is they want to participate in extreme sports activities to balance out a sedentary lifestyle. This is a recipe for disaster. 

I like two drills to get people up to speed before they try to complete a Tough Mudder race or their local 5K in minimal shoes or barefoot.

#1. I prefer the free standing calf raise exercise with emphasis on the keeping the big toe flat against the floor. This will cause a good stretch in the bottom of the foot and really stress the fascia to mobilize the entire foot.

#2.  If you have access to a horizontal leg press, I like this drill to strengthen the PL muscle:



It is simple to do--especially with the general population-- and really enables them to target those muscles without confusing them with balance and coordination. Both drills should be performed slow and under control to stress the areas effectively. There are a number of other ways to target the muscles that encompass the lower legs--these have worked well for me. Give them a try!

5 comments:

  1. This is great.. Address a problem I have with my dance practice. Hindu squats are now on my list!

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  2. I would be interested to hear what you do for the opposite issue, pronation - often combined with flat feet.

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  3. I love this article. I'm going to incorporate the drills for sure

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  4. I'm not sure I understand the role of the second exercise. The resistance from the leg press machine is going through the heel/back of foot so it's not actually providing resistance to the muscles performing dorsiflexion (which the PL doesn't do). Is it to serve a different function?

    Ryan

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  5. Great article. I have recently been training a lot of foot and lower limb imbalances and injuries. Its amazing how little is done to correct the muscular problems of the foot and ankle. More often than not any problems are treated with corrective footwear that serves as no more than a brace causing the muscles to imbalance even further.

    I have been working on minimalist footwear progressions with many clients who have had life long lower limb and foot problems as well as incorporating exercises like the ones you have shown. I have seen great results.

    Thanks for the article

    Kurtis
    kineticforcefitness.wordpress.com

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