Optimal Sprinting Performance: A Foot Fetish

Jason Cholewa – Follow me on twitter

Follow me on linked in

Powerful Feet for Powerful Athletes

     What is the missing link in training for athletic performance? If you are in my KHP350 Strength and Conditioning class you no doubt have heard me discuss ad nauseum the importance of glutei training for strength and power during running and jumping.  But what if your athlete’s have highly functioning glutei and great strength, power, and mechanics, what else can be done? The answer is so simple, it might surprise you: train the toes!

How Important is the Large Toe?

Interestingly, Lee and Piazza (2009) reported that elite sprinters had longer toes than non-sprinters. The researchers demonstrated that longer toes permitted a greater maximal forward driving force at toe push-off during sprinting. It’s quite evident that the metatarsal phalangeal joint (MPJ) is the final link between powerful hip, knee, and ankle extensors force generation and the ground.  Additionally, the MPJ displays the greatest range of motion in the sagittal plane of any foot joints.  Anatomically, the long head of the toe flexor muscle group comprises 10% of lower leg musculature (Wickiewicz et al., 1983).  The short head of the toe flexor muscle group comprises 80% of foot musculature (Kura et al., 1997).

Big toe flexor muscles

Observe the image below, the force generated during the triple extension in sprinting is transferred through the MPJ into the ground.  The degree of MPJ hyperextension (the loss of foot rigidity) represents inefficiency in ability of the athlete to apply maximal force into the ground.  I liken this effect to being asked to hop on repetitively and quickly on the balls of your feet. In the optimal case your ankle remains fairly rigid and you sprint back up with each landing. In the case of inefficiency, each time you land your ankle flexes significantly (i.e.: is unable to maintain stiffness) and your heel taps the ground.

The greater the degree of big toe dorsiflexion (hyper-extension) the larger to loss of forces transmitted into the track.

Another reason training the large toe flexors are important may be injury prevention.  Ray Lewis, one of the toughest Line Backers to play in the NFL, missed several weeks due to a sprain at the MPJ (turf toe).  Turf toe can occur when the ability to resist MPH hyper-extension (toe flexor strength) is inadequate, especially during high velocity situations, such as sports (image below).

How Adaptable are the Big Toe Flexors?

Goldmann et al. (2012) trained 15 recreational athletes for seven weeks.  The training program involved subjects performing 4 sets of 5 isometric repetitions (3 s contraction, 3 s relaxation) with 90% of maximal voluntary contractile force 4 times per week.  Subjects continued their daily activities, but were restricted from starting a new exercise program. A control group of 12 equally matched subjects continued their daily activities with no additional toe training.

Seven weeks of isometrical toe training improved MPJ flexion force production by 60-70%.  Ankle plantar force also increased with toe training. Collectively, one might expect to see an increase in ankle or MPJ power during walking, jogging, or vertical jumping; however, there were no differences between groups, possibly due to the lower external MPJ hyper-extension forces exerted during these movements.

In contrast, the horizontal jump generates three times the maximal external MPJ hyper-extension forces compared to jogging or jumping vertically (see image below). This occurs because the athlete must move the center of mass past the toes as takeoff occurs, compared to the vertical jump where the center of mass stays slightly behind the toes. Ironically, the movement in the horizontal jump is very similar to that during maximal velocity sprinting.  In simple terms, more force is lost as the toe bends during horizontal jumping (and likely sprinting) compared to jogging or vertical jumping.

Compare the difference in the relationship between the placement of the center of gravity and the toes at take off during the horizontal and vertical jumps.

Goldmann et al. reported toe training significantly increased MPJ mechanical power during the horizontal jump.  Theoretically, if big toe rigidity is increased during high external forces, then force transmission from the posterior kinetic chain into the ground will increase, and horizontal jump should improve. Indeed the horizontal jump did increase with toe training. The training group saw a 6 cm increase in horizontal jump, compared to only 1 cm in the control group.

Application

Goldmann et al. designed special dynamometers to determine MPJ maximal flexion and to train utilizing 90% maximal force. In strength and conditioning facilities whereby space and/or funds is at a premium, a quality platform or glute-ham-raise will likely produce a higher return on investment than a toe dynamometer. That said, there are two inexpensive, space-friendly, and convenient methods in which to train MPJ flexion.

The first application is with the use of resistance bands (image below).  The toe flexors operate during the horizontal jump or sprinting to hold the foot in a rigid lever.  When toe hyper-extension occurs this lever bends, and forces are lost. In keeping with this theme, training toe flexion utilizing an isometric or even eccentric manner will likely produce the largest results. According to the results reported by Goldmann et al., 4 to 5 sets of 5-8 reps per foot 3 to 4 times per week will produce results within two weeks and you should continue to see improvements so long as the toe flexors are overloaded progressively. What’s more, your athletes can train in the evening while watching Monday Night Football or Duck Dynasty.

Band resisted MPJ flexion exercises. Notice the phalangeal joints do not flex (i.e.: my big toe is always extended).

Athletes may also be able to increase MPJ flexion force by simply increased daily foot structure loading.  Bruggermann et al. (2005) reported a 20% increase in toe flexor strength and a 4-5% increase in toe flexor CSA following 5 months of switching from conventional sneakers to ones with a highly flexible sole (i.e.: Vibram Five Fingers, New Balance Minimus, etc.).  Simply put, spending more time barefoot and training in minimalist sneakers should increase foot lever rigidity during sprinting and horizontal jumping.

It’s likely that a combination of band resisted toe flexion work and training in minimalist footwear will have the greatest impact on MPJ flexion force. If MPJ flexion strength is increased, this should translate into a more rigid foot lever (i.e.: less force loss during toe off movements).  Thus, tasks where the center of gravity moves anterior to the large toe and large forces need to be transmitted into the ground (such as sprinting and broad jumping) will reap the largest benefit from big toe training.  So, the missing link between good performance and explosive performance may just be a bum toe.

References:

Bruggermann et al. (2005). Effect of increased mechanical stimuli on foot muscle functional capacity. International Society of Biomechanics, XXth Congress, Cleveland, OH.

Goldmann et al. (2012). The potential of toe flexor muscles to enhance performance. Journal of Sports Sciences, (Epub), 1-10.

Lee & Piazza. (2009). Built for speed: musculoskeletal structure and sprinting ability. The Journal of Experimental Biology, 212, 3700-3707.

Kura et al. (1997).Quantitative analysis of the intrinsic muscles of the foot. Anatomical Record, 249, 143-151.

Wickiewicz et al. (1983). Muscle architecture of the human lower limb. Clinical Orthopaedics and Related Research, 179, 275-283.