Sprint Faster By Using Your Legs As Hammers | Sprinting Workouts by ATHLETE.X

Optimal sprint performance is limited by one’s ability to rapidly and repeatedly produce and apply forces. How the athlete orients these forces into the ground is arguably of greater importance than how much force can be produced in total, as force produced in the wrong direction will invariably send you somewhere other than where you want to go (i.e. toward the finish line).


It must be stated that your total ability to produce force will limit the technique that you can express, seeing as there is a certain amount of force production you need in order to overcome gravity and propel yourself through the air. Regardless, there is certainly a skill component of sprinting, and manipulating one’s method of movement can significantly impact how fast they ultimately can sprint.

Every coach is going to have their own opinion, cues, and beliefs as to how much technique should or should not be manipulated. I think that there can be a tendency to avoid coaching technique when a coach has never

So, this brings us to the question of the hour: What theoretical model of movement should we apply to sprinting?

Swing The Hammer

If you’ve ever worked in construction, fixed something at home, or re-enacted a scene from Ted Bundy’s life, you likely have some familiarity with hammers. The hammer offers us a solid analogy for the mechanics of using your legs during sprinting.

To properly drive a nail into a wall, you would be best suited to wind up and swing the hammer through a large range of motion, leading to an abrupt strike of the nail. We do not press or push the nail into the wall, but rather apply large forces over a short duration to tack the nail into the wall.

By swinging the hammer, we achieve two ends:

  • Efficient production of force.
    • We load the tissues of the shoulder, arm, and torso elastically, using stretch shortening cycle activity to initiate the swing. Utilization of elastic tissues and stretch shortening cycles allow for the production of force at relatively lower levels of effort.
  • Efficient application of force.
    • We accelerate the hammer through the air, meaning that the hammer in increasing its kinetic energy as it approaches the nail. The moment of contact with the nail is the moment at which the hammer is exhibiting the largest amount of kinetic energy - energy it will transfer into the nail to send it into the wall.

Your Leg Is The Hammer

We can apply the same concept to sprinting, using the leg as the hammer and the ground as the nail. Put plainly, we sprint by winding the leg up and striking the ground in a similar manner that we see with driving a nail into a wall using a hammer.

  1. By winding up the leg, we can utilize stretch-shortening cycle activity in the hamstrings, glutes, calves, and adductors to generate force in an efficient manner.
  2. This SSC action helps accelerate the leg through the air, leading to an increase in kinetic energy as the leg approaches the ground.
  3. Upon contact the ground, this kinetic energy is used to produce ground reaction forces which ultimately help send the sprinter through the air into the next ground contact.

This winding up motion has not only been confirmed effective for me, my athletes, and my colleagues, but also in sprinting research.

Ken Clark of the SMU found that, contrary to how running at slower speeds is produced by the bouncing off of the ground (as seen in the spring model of running), sprinters actively “punch” or strike the ground. That is to say, they do not passively wait for the ground and bounce off of it like a pogo stick - they actively attack the ground with forceful swinging of the leg & foot into the ground.

“We found that the fastest athletes all do the same thing to apply the greater forces needed to attain faster speeds,” Weyand said. “They cock the knee high before driving the foot into the ground, while maintaining a stiff ankle. These actions elevate ground forces by stopping the lower leg abruptly upon impact.”

The conclusion that researcher’s came to was that, similar to the hammer analogy, faster sprinters accelerate their legs through the air toward the ground, resulting in a high output of force and a short duration of ground contact.

Other research tells us that eccentric load on the hamstrings & negative work at the knee increases with running velocity. We also know, through observation, that virtually every fast sprinter exhibits a forward floating of the shank (lower leg) just before the leg whips back & under them toward the ground. When the late & great Charlie Francis would cue “whip from the hip”, this forward & backward whipping motion of the leg is what he was referring to.

It is this floating of the lower leg which loads the hamstrings eccentrically in the late swing phase, and it is the reversal of this movement back under the sprinter which leads to the application of large, properly oriented forces into the ground. This amount & quality of application of force into the ground is what allows sprinters to run at high velocities.

The problem is that most athletes are too tepid, afraid, or weak to exhibit optimal sprint mechanics. Athletes may let the lower leg float in front of the knee, but they fail to whip it back under them subsequently over-stride or pull their hamstring. Other athletes may accelerate well early in the sprint, but they fail to let the leg open up on the front side and thus can never achieve the velocities that you might expect based solely on their acceleration performance.

Adjusting Sprint Technique

Changing technique is as simple as seeking a different feeling when you move. We create movement by feeling certain sensations, so it follows logically that to change movement we should seek different feelings. Before we get into what you should do, let’s quickly discuss what you shouldn’t do.

How Not To Sprint

To run slow, look like an idiot, and get hurt, do the following:

  • Exhibit Bad Posture - Excessive forward or backward lean will inhibit your ability to attack and contact the ground effectively. Posture is the gatekeeper of what movements you can make. Don’t believe me? Try sprinting while laying down.
    • Instead, we want to see an upright, neutral posture with your head over your torso and your torso over your legs at ground contact.
  • Over-stride - Reaching & crashing with your foot moving forward at ground contact is a great way to slow down every step and risk serious injury. Over-pushing & exhibiting backside mechanics will often lead to this suboptimal movement pattern.
    • Instead, we want to strike under our center of mass which will generally be under the chest or head if you have good posture. For athletes who chronically over-stride, this may at first feel like you are striking too far back. As you adjust to changes in technique, your awareness of where you strike the ground will likely change as well.
  • Be Tense - Trying hard, contracting agonists and antagonists at the same time, and moving without clarity or relaxation is a fast track to slow sprinting. You cannot propel yourself forward with your glutes and hamstrings if you hip flexors are working in the opposite direction. Similarly, you cannot initiate the forward movement of the thigh if your glute is still pulling the leg backwards.
    • Instead, we want to feel relaxed, light on our feet, and smooth in our movements. Sprinting should feel like a series of blips or pulses of effort, not one continuous straining movement such as you would see in a maximal effort lifting attempt.
  • Be Passive & Soft - Passively contacting the ground without low reactivity, poor ankle rigidity, or a laziness in getting off of the ground will increase ground contact times and eliminate your ability to efficiently apply force in the direction you want to go within constraints of time necessary for sprinting.
    • Instead, we want to see an athlete be active in their leg swing, reactive when hitting the ground, and overall generally see joint rigidity in the legs during ground contact.

With the basics out of the way, let’s wrap things up but talking about the hammer action of the leg.

The Hammer Approach To Sprinting

As stated, we want to sprint with a hammer-like action. That is, we want to wind the leg up and actively, aggressively strike the ground with a downward and backward swing of the leg. This swing of the leg through the air will accelerate the leg into an abrupt and forceful strike, which will launch the athlete through the air if optimally executed.

The best way I can describe this technical approach to sprinting is like this:

  • When in the air, somewhere around when you hit peak hip flexion, you want to pull the leg through the air, toward the ground, in a downward and backward arc.
  • Once you sense the ground, you should already be initiating the next downward pull through the air on the opposite leg.
  • Alternatively, you can focus on popping the thigh forward , feeling the “whip from the hip” sensation of launching the leg forward and quickly whipping it back under your body.
    • Some athletes might respond better to “pick the foot up”, particularly if their hamstring control (and thus foot float control) is suboptimal.

When I say to pull through the air, it is imperative that you understand you should not feel yourself pulling your body over the ground while on the ground. If you feel yourself trying to swing the leg backward while on the ground, you are executing this movement too late in the stride cycle. The only thing you should feel on the ground is your foot briefly contacting the ground, getting back up into the air as soon as possible.

Some athletes may find that they can successfully sprint with both forward and backward movement sensations, such as a combination of pop the thigh forward and whip the leg back. On the other hand, some athletes are better suited to focus on one movement, either pop the thigh forward, whip the leg back, pull through the air, etc. It is important that you choose cues based on what the athlete can interpret and handle, not what you think is objectively the best cue for everybody. If you learn to execute this movement properly, you can really enhance your sprinting capabilities to a large degree.

You should be feeling this “pull through the air” as soon as you are a few strides into your sprint and your initial pushing in the start is over with. In acceleration, you will feel more of a backward oriented pull through the air, whereas at top speed it may feel more downwardly oriented. Either way, the leg should exhibit an arcing motion through the air.

When properly executed, this will send you back up into the air with enough time to reorient your limbs for the next strike, but not so long that you fail to move in a significantly horizontal manner toward the finish line.

Personally, I saw a significant drop in my 30 meter flying time when I was able to really get this “pull through the air”. I went from a personal best of 2.91 to a 2.81, ending the workout with a 2.88. Similarly, my best 30-40 meter split is a .92, and this was achieved by also pulling through the air and then reactively getting off of the ground.

Other Considerations

It is imperative that you have the requisite hamstring strength in both eccentric and concentric modes of action in order to properly swing the leg and whip from the hip. Exercises such as the RDL, single leg back extension, nordic curl, razor curl, straight leg bounds, and long stride lunges may all help develop hamstring strength at long muscle lengths and in multiple modes of action. Also, you can use something like a pendlay row to target isometric hamstring strength as they act as postural support during the exercise.

You can work on the cues of pulling the leg through the air in various drills, and I find that dribbles are a great way to groove this movement into your sprinting. My warmup consists of dribbles and dribble-like variations, and I progress them in range of motion and velocity throughout the movement. When you can pull the leg back through the air to the ground during a dribble, you still start to get a feel for what it means.

I would strongly suggest that you film yourself during drills, sprinting, etc., and review the film to see what is happening. Are you pulling the leg through the air? Is it landing under you? Are you getting off of the ground without over-pushing? Is your posture stable and neutral? All of these things can be looked at on a daily basis to see how your technique is progressing.

Back to blog