In the world of sprinting, our ability to sprint is limited most by how we apply force to the ground more so than how much force we put into the ground. Smashing the ground with your foot moving forward or out to the side is less effective than producing less force that you’re better able to apply into the ground in the proper vector.
Because biomechanics and sprinting technique do play a pivotal role in whether we stay healthy and run faster or stay injured and run slow, it is important that we all have a fundamental, GED level understanding of what to look at when analyzing the sprint form of yourself or athletes that you coach.
If after ingesting this information you feel that you need some extra help with analyzing your sprinting technique, make sure to check out my technical analysis service at SprintingWorkouts.com.
Big Ticket Items
Today we are going to cover some big ticket items which I think are of significant importance for all athletes. The information shared here has been gathered over time by learning from my mentors such as Dan Pfaff, watching film of sprinters from developmental levels up to elite performers, studying sprinting related research, and in my own personal experience as an athlete and coach. Some of the things I say may be debated by others, but overall the qualities discussed here are commonalities that can be seen in many athletes of varied skill levels.
In no particular order, here is what we are covering in this lesson:
- Posture & Axis Behavior
- Rhythm & Frequency Progression
- Direction Of Force Application
- Center Of Mass Elevation
- Limb Symmetry
- Ground Contact Qualities
- Flight & Ground Contact Time Progression
- Injuries & Compensation Patterns
Understand that many of these categories or topics are inter-related, and they should not be looked at in silos but rather as an integrative complex system.
Posture & Body Axis Behavior
When analyzing sprint technique, the first menu item I look toward is body posture, as well as how the different axes of the body move and interact.
Posture can be defined as the overall positioning of the body, with a specific focus on the positioning and orientation of the spine and pelvis. Our limb actions are limited by the actions of the spine and the pelvis, and therefore these are the areas we look to first when analyzing sprint technique.
There are different axes (the plural of axis) in the body, such as the longitudinal axis of the spine, transverse axis of the shoulders and hips, longitudinal axis of the foot, just to name a few.
As we progress from a stationary position and begin to sprint, the longitudinal axis of the spine will rotate vertically each step until upright sprinting is reached. If you are analyzing someone’s sprint technique, the first thing to look for is whether or not they are exhibiting this progression from a more forward oriented body position to an upright body position at the end of acceleration.
When we stay too low and do not raise our posture, we can reduce the space available to cycle our limbs through to the next stride, leading to poor quality ground contacts and raising the risk of injury as a result.
Another aspect to pay attention to is the movement of the shoulder and hip axis during sprinting. The shoulder and hip axis will undulate and oscillate each step in a harmonious manner, counterbalancing one another.
Any excessive movement or lack of movement in these axes is worth investigating, as there may be some compensation pattern or injury situation that needs to be dealt with that is inhibiting the natural harmonious movement of these joint systems.
A good point in the stride cycle to analyze posture is when the knees come together. This can give you a consistent point at which to analyze posture as the athlete accelerates, and will give insights as to how the athlete manages their body positioning while in space.
Rhythm & Frequency Progression
Rhythm is defined as “a strong, regular, repeated pattern of movement or sound”. In sprinting, rhythm refers to the progression of frequency or pace at which someone moves as they accelerate, reach maximal velocity, and then minimize deceleration through the end of the race. Rhythm can be assessed visually or audibly, by either watching the athlete’s movements or by listening to their ground contacts.
For most sprinters, issues with rhythm will be centered around overcooking their frequency too early, reaching maximum stride frequency too soon, or exhibiting an inconsistent rhythmic progression throughout the sprint.
Throughout a sprint, an athlete’s rhythm should progress from slower to faster, consistently throughout the acceleration. Athletes should aim to seek a smooth build up of frequency as their posture rises and they progress down the track. Athletes who increase their frequency too early, or lack the progressive increase of frequency throughout the sprint will tend to reach maximal velocity too early and spend too much of the sprint decelerating. Having the highest stride frequencies in the first 20 to 30 meters of the sprint distributes energy poorly, leaving you with nothing left for the back half of the race. In contrast, sprinters who manage their rhythmic progression and stride frequency progression properly will be able to run the entire race better, as they will spend less time decelerating and have more energy available later in the sprint.
Some research has shown that faster sprinters exhibit longer ground contact times during the first step as compared to slower sprinters, while also showing much shorter ground contact times later in the sprint. While some of this is impacted by their force output and application characteristics, this also speaks to how the elite sprinter is a master of their rhythmic progression through the sprint.
We sprint fast when we master our ability to apply force, project through the air, reorient our limbs, and repeat the process. Since the early phases of the sprint require athletes to overcome inertia and create large projections, the earlier steps of a sprint will inherently be more force dependent and therefore take longer than strides closer to maximal velocity.
Direction Of Force Application
JB Morin’s study from 2011 states that “Force application technique is a determinant factor of field 100-m sprint performance, which is not the case for the amount of total force subjects are able to apply onto the ground.” Put simply, the direction that you apply force to the ground is more important than smashing the ground with maximum force that is applied in a disadvantageous manner.
Early in the sprint, forces are directed more horizontally, with this horizontal vector of force decreasing as the athlete’s posture rises, their rhythm increases, and they eventually reach maximal velocity. Once maximal velocity is reached, net resultant horizontal forces are zero, and the athlete’s job becomes focused on applying force vertically to ride the wave of momentum that was built up during the acceleration.
In my experience, it is more common to see athletes get caught trying to be too horizontal with their force applications in upright sprinting, overpushing behind them and overreaching in front of them.
Instead of trying to reach in front or push behind themselves during the sprint, athletes should aim to attack the ground in line with the longitudinal axis of their body, aka they should be striking the ground vertically.
The athlete should always be producing force vertically relative to this long axis of the body, as this will help generate horizontal forces relative to the ground during acceleration when their posture is angled forward, and produce vertical forces relative to the ground when they are in upright sprinting. This simplifies ground force application, as the athlete does not have to do anything different with their legs as they rise through acceleration.
When in doubt, cue the athlete to pick the foot up and set the foot down, rather than cueing them to push backward or reach forward. Only in cases where athletes show little horizontal projection in acceleration should they be cued in a horizontal manner.
Center Of Mass Elevation
Just as the body angle and posture should rise from horizontal to vertical during acceleration, the athlete's center of mass should also rise as they sprint. If the athlete changes their body angle but does not raise their center of mass, they will end up bounding or lunging their way down the track, exhibiting ground contacts too far in front and toe-offs too far behind the body.
Projecting the center of mass upward each step creates space between the athlete and the ground, and this allows for the athlete to reorient their limbs in preparation for the following ground contacts.
Athletes who step side to side during acceleration or any point thereafter are compensating for their center of mass being too low, as the body senses that it needs to find space to avoid falling on its face. Side to side sprinting creates undue stress on the adductors and achilles tendon, and can set up athletes for groin, hip, or ankle injuries if left unaddressed.
All athletes are going to exhibit asymmetries in their body movements, but generally speaking sprinters need to show symmetries between limbs as they sprint. These symmetries can be from front side to back side, such as between the front arm and back leg, or they can be contralateral, such as between the left leg and right leg. Similarly we will see symmetries between the front and back leg, as well as the front and back arm.
For example, as the left leg reaches the thigh block position and begins to reverse downward toward the ground, the right arm should move down at the same time. Actively swinging the arm downward in tandem with the leg can help contribute some weak forces to the ground strike.
When looking at the arms and legs, there are moments where we see that angles of the forearm, humerus, thigh, or shin will mimic one another. Significant deviations in angulation between the arms and legs can inhibit the stride pattern and lead to what looks like tense or poorly coordinated sprinting.
At thigh block just after toe off, we can look for similar angles between the front shin, front forearm, back forearm, and back thigh. The front thigh and back humerus should block at the same time and with similar angles in order to allow for a smooth limb exchange throughout the stride cycle.
In the stance phase when the knees are together, the forearms should mimic the thigh angles, and deviations from this can lead to rotational issues. Just prior to ground contact, we can look for the back forearm to mimic the front shin angle, with the front forearm mimicking the back shin angle.
We can also look at the limbs relative to the torso. For example, during acceleration, the shin angle at mid stance should be similar to the angle of the torso. Significant deviations from this make it hard to time and execute good quality projections off of the ground.
Ground Contact Qualities
As stated previously, how we contact and interact with the ground is of fundamental importance to our ability to sprint. Athletes may contact too far out in front of the body, spend too much time on the ground, or they may cut their stride cycle short and not spend enough time on the ground.
Typically at ground contact during upright sprinting, we want to see the heel vertically aligned with the ilium, the front of the hip bone. As the hips pass over the foot and we reach mid-stance, most sprinters will exhibit heel drop and a brief moment where they are flat footed on the track. At the same time, the knee and hips should bend slightly, which allows for the leg to be compressed like a spring at the ankle, knee, and hip. This compression of the spring then gives the athlete the ability to push off of the ground and launch back into the air for another stride.
During upright sprinting, the athlete should focus on either applying force vertically with a downward leg movement, or be cued to simply pick the foot up off of the ground as soon as they feel it, letting the leg strike happen naturally. Cueing athletes in a horizontal or forward and backward manner in upright sprinting is not advisable for most athletes, as this can lead to excessive ground contact times, overpushing, and skew the athlete toward over-rotating or exhibiting excessive back side mechanics. There may be some cases where athletes need more anteroposterior oriented cues, but these should be saved for special circumstances and rather than being applied liberally to all athletes.
Flight & Ground Contact Time Progression
Another area of focus when discussing sprint mechanics is the progression of flight times and ground contact times as athletes accelerate to maximal velocity. Just like our rhythm should progress from slower to faster throughout the sprint, so should our ground contact times.
Early in the sprint, ground contact times should be approximately twice as long as our flight times. Because we are overcoming inertia during early accelerations, ground contact times need to be long enough for us to produce horizontal propulsive impulses. As we build momentum and increase sprinting velocity, ground contact times will reduce and flight times will increase, such that somewhere around mid acceleration we will see a 1 to 1 ratio between ground contact and flight times. As we continue to accelerate into upright sprinting and top speed, flight times will overtake ground contact times, ending up with flight times somewhere around 1.6 times the duration of ground contact times.
Our ability to progress our contact and flight times will depend on the factors previously discussed, such as our postural progression, rhythmic progression, our vertical center of mass displacement or elevation produced by each stride, limb symmetries which allow for smooth movement, and the quality and orientation of our ground contacts.
Injuries & Compensation Patterns
One thing to consider when analyzing sprint technique is that old or current injuries can have a major impact on how an athlete moves. These impacts may be clear, such as a hamstring injury inhibiting knee angulation, or they may be more subtle, such as a left shoulder injury leading to hip, knee, or ankle issues on the right side of the body.
Once basic strength and mobility factors are accounted for in training, aberrant movements in sprinting should be looked at with some consideration for how an old injury could be manifesting in restricted or altered ranges of motion. Some of these patterns may be fixable and worth working on, but there may also be cases where a compensation pattern is better off left alone.
It is important to watch video from the front, back, side, and even from above, as these different viewing angles can give insights into different rotational qualities of the athlete’s movement, show you timing and synchronicity between limbs, and can sometimes give an explanation for something that another viewing angle does not elucidate.
Sprint technique is something that all coaches and athletes should have some basic understanding of, and the ability for one to analyze sprint technique is a useful tool in the quest for faster sprinting speeds.
Athletes and coaches should first pay attention to the postural and rhythmic progressions that sprinters exhibit as they accelerate, reach maximal velocity, and then attempt to maintain speeds as they decelerate. Additionally, attention should be paid to the vertical displacement of the center of mass.
Once these core fundamentals are present or at least being worked on, some focus can be given to the limb symmetries and harmonic limb exchange qualities of the athlete, looking with a keen eye for situations where athletes are limited in their range of motion, either by coordinative factors or physical blockages that can be targeted with therapy.
It is important that athletes do not get caught up in overanalyzing their movement during practice, and coaches should be prudent to avoid over cueing or overcoaching on the track. Some cues can be useful, but it is far more easy to say too much and confuse the athlete than it is to give simple instructions that have a beneficial effect. When in doubt, say less during the session, and give more instruction after the session.
Ultimately, all athletes can improve their sprinting technique, and by doing so can have a better shot at running faster and staying healthy. Seek incremental improvements over time, and keep track of what works and what doesn’t. With time, focus, and repetition, we can all see benefits in our sprinting by giving some effort toward improving our sprinting technique.