Thanks to advances in smartphone technology, athletes and coaches can easily assess their force velocity profile during sprinting and jumping through the use of the My Sprint and My Jump 2 apps. For the sake of our discussion today, we will be using the My Sprint app to assess force velocity profiling as it relates to acceleration sprinting.

To assess your power force velocity profile as it relates to sprinting, all you need are a track, some cones, a smartphone, and the MySprint App.

Step 1: Cone & Camera Setup

Measure out cones (or even better some vertical PVC pipes) at 5.57m, 10.28m, 15m, 19.72m 24.43m, and 29.15m. The cones are placed at these specific distances so that, when your camera is placed 30 meters away from the 15 meter cone, your camera sees you as you cross every 5 meter mark. Because of the viewing angle of the camera throughout the sprint, the cones need to be placed in this manner.

Place your camera 30m from the 15m cone, perpendicular to the running area, so that you can capture the entire sprint. It is preferable to have a partner pan the camera throughout the sprint, but not required if you are working by yourself.

Step 2: Recording

If you have a partner, you can record yourself in the app itself. If you are filming yourself, record in your phone’s camera app using slow motion video, and then import that slow motion video as a full speed video into the app. 

The app itself cuts off recordings at 60 seconds, which is why you should record outside of the app when filming yourself.

We import the slow motion video into the app after converting it to full speed (such as in your iPhone using the video editing options), as this allows for the app to interpret the footage properly.

Step 3: Capturing Times

Once the video is imported, you can begin registering your times.

Use the left and right arrows or the slider until you see your very first bodily movement. We want to make sure we are very honest and accurate with the first movement. Once found, press the “start” button to register the beginning of the sprint.

Continue moving forward through the video, registering each time that you pass a cone. Make sure to be very consistent with which part of your body you use, such as measuring each time your hips cross the cone. Using your chest for one cone and hips on another will generate inaccurate results.

Step 4: Results

Once you are happy with the times registered in step 3, you can hit the “FV Analysis” button on the bottom left of the screen. If instead you were using the My Sprint app for timing splits, you could hit the splits button.

Ensuring Accurate Results

Because of the sensitivity of the calculations used for generating your Power Force Velocity Profile, it would be wise to perform 2-3 runs so you can ensure that the results you get are relatively consistent. By measuring multiple runs, you can generate a range of results, averages, etc. 

Over time you can track absolute results, changes in averages, or whatever your heart desires. This can also be useful for assessing the validity of certain cues, using PFVPs from different sprints to see if the cue you used had any impact on improved sprinting or not.

If your phone is too small, or you’re having trouble with consistent measurements, you can import your video into free software called Kinovea, using the stopwatch function to register what times you crossed each cone zone. 

From there, you can go into the My Sprint app and enter in the time registered in Kinovea. Since Kinovea is a desktop program, you can use your larger computer screen and the zoom function to be certain of what time your chest or hips crossed the cone.

Before we go forward, you need to know what ratio of force means.

In sprinting, ratio of force is defined as the direct measurement of the proportion of the total force production that is directed in the forward direction of motion, ie, the mechanical effectiveness of force application of the athlete.

The higher the value, the greater the proportion of your force production is being applied horizontally. Fast sprinters have higher ratios of force than slower sprinters, as they are better at applying force horizontally into the ground. Slower sprinters might produce large forces, but they are not directed into the ground in an effective manner, such as in the form of braking forces or more vertically oriented forces.

Within the app itself, the following variables will be shown after processing your Power Force Velocity Profile.

Variables measured within the app:

V Max - Maximal velocity reached during the sprint. Higher numbers are better.

F0 (N) - Theoretical maximal force production in Newtons. Higher numbers are better.

F0 (N/Kg) - Maximal force output (per unit body mass) in the horizontal direction. Corresponds to the initial push of the athlete onto the ground during sprint acceleration. The higher the value, the higher the sprint-specific horizontal force production.

V (0) - Sprint-running maximal velocity capability of the athlete. Slightly higher than the actual maximal velocity. The theoretical maximal running velocity the athlete would be able to reach should mechanical resistances (ie, internal and external) against movement be null. It also represents the capability to produce horizontal force at very high running velocities.

P Max (W) - Maximal horizontal power output in Watts. Higher numbers are better.

P Max (W/Kg) - Maximal power-output capability of the athlete in the horizontal direction (per unit body mass) during sprint acceleration.

DRF - Describes the athlete’s capability to limit the inevitable decrease in mechanical effectiveness with increasing speed, ie, an index of the ability to maintain a net horizontal force production despite increasing running velocity. The more negative the slope, the faster the loss of effectiveness of force application during acceleration, and vice versa.

FV - Force velocity imbalance. Numbers below 100 = force deficit. Numbers above 100 = velocity deficit. 100 = a balanced force velocity profile. Numbers closer to 100 are better.

RF 10m - Your ratio of force at 10 meters. Ratio of force = Horizontal Force divided by Total Force. The greater the RF, the more effectively your force outputs are being applied horizontally to the ground. Higher numbers are better.

RF Peak - Theoretically maximal effectiveness of force application. Direct measurement of the proportion of the total force production that is directed in the forward direction of motion at sprint start.

In general, if we can measure an upward trend of P Max (W/Kg), RF 10m, RF Peak, and V Max, the athlete should be improving their sprint times. Additionally, we want DRF to go down, as we want less of a decrease in the ratio of force as the athlete accelerates. The fastest sprinters are far better than slower sprinters at being able to apply horizontal force as they accelerate, which indicates they have lower DRF than slower sprinters.

Once you have completed your PFVP, you can go about analyzing your results and modifying your training program accordingly. Depending on the significance of your imbalance, you can decide how to proceed toward balancing your PFVP.

High Force Deficit (FV < 60)

For those with a high force deficit, the bulk of your training needs to be dedicated to producing high forces and high amounts of power at relatively lower velocities.

An example training load ratio for this type of athlete could include 3 units of strength training, 2 units of strength-power training, and 1 unit of power training.

On the track, athletes with large force deficits can benefit from incorporating various forms of resisted sprinting to their training, such as using heavy sprint sled pulls for acceleration, parachute sprints for maximal velocity sprinting workouts, weight vests, and even something like the Exogen body suit. Additionally, these athletes could choose to sprint into a head wind and up a hill if they do not have resisted sprinting tools to use.

These athletes should be cued toward producing forceful horizontal strikes into the ground during early acceleration, and to avoid rushing their stride frequency.

Low Force Deficit (FV = 60-90)

For athletes with a low force deficit, training should still focus on generating more force, but in a manner that is less dependent on the heaviest strength exercises, and slightly greater emphasis on power compared to those with a high force deficit.

An example training load for athletes with a low force deficit could include 2 units of strength, 2 units of strength-power, and 2 units of power.

On the track, athletes with a low force deficit should still be incorporating resisted sprinting methods in their training program. Low force deficit athletes can benefit from starting out with an emphasis on resisted sprinting methods, shifting toward complexes which include both resisted and non-resisted sprints in their sprint training.

Well Balanced FVP (FV = 90-110)

Athletes with a well balanced force velocity profile should keep their training relatively balanced.

An example training load for athletes with a well balanced FVP could include 1 unit of strength, 1 unit of strength-power, 2 units of power, 1 unit of power-speed, and 1 unit of speed.

On the track, these athletes can use a mixture of resisted and unresisted sprinting, with the majority of their sprint training being performed without resistance. These athletes are prime candidates for using a typical Charlie Francis style training program, with vertical integration of a wide variety of biomotor qualities being used.

Low Velocity Deficit (FV = 110-140)

For athletes who show a low velocity deficit, training should remain balanced but with a tilt toward a velocity based emphasis. For example, they might benefit from contrasts and complexes of exercises, such as a low load counter movement jump followed by a band assisted jump.

An example training load for these athletes could include 2 units of speed, 2 units of power-speed, and 2 units of power.

On the track, these athletes should avoid long, grueling runs and instead focus on shorter sprints with solid recovery. Being at a velocity deficit, it would be ill-advised to perform large volumes of slower sprinting, as this could impede their progress in trying to develop high velocity sprinting capabilities. While some tempo running or circuit training could be used on low intensity days, these slower forms of training should not dominate the program.

High Velocity Deficit (FV > 140)

For athletes with a high velocity deficit in their power force velocity profile, the training program needs to be more narrowly focused on higher velocity training both on the track and in the gym compared to other athletes. These athletes should avoid slow, straining types of heavy strength training, and instead be focused on lighter movements that are executed at higher velocities. Band assisted jumps, sprinting with a tail wind, basic plyometric progressions, and maximal velocity sprint training can be a focus for these athletes.

An example training load for these athletes could be 3 units of speed, 2 units of power-speed, and 1 unit of power.

Similar to those with a low velocity deficit, athletes with a high velocity deficit need to avoid slow grueling runs like the plague. Instead, they need to be exposed mainly to fast sprints with full recoveries, making sure to monitor training volumes so that they do not end up running much of the workout slower than what they’re capable of. These athletes likely need some technical instruction as well, as they likely exhibit typical issues like staying on the ground too long, over-striding, exhibiting poor posture, and failing to compress the leg during the swing phase.

Staying Healthy When Improving Force Deficits

Because of the higher loads and slower velocities used when improving force deficits, athletes should pay attention to their mobility and stiffness, as well as their spinal and joint health, to make sure that they are not turning into a brick as a result of focusing on improving force outputs.

For example, if back squats make your torso stiff, consider using step ups or split squats which utilize lower loads but provide a similar challenge to the legs for generating force. A belt squat machine or leg press might be a good option to try as well. Incorporating mobility work in your warm ups and cool downs can help, as can making sure you have some low intensity days that are dedicated to general strength, general mobility, and allow for your system to calm down between the more intense workouts.

If stiffness becomes pervasive and is starting to impact your sprinting, add in an additional rest day, make sure you’re ingesting enough magnesium and potassium in your diet (such as through a lot of leafy greens), and consider investing in a foam roller or massage gun.

Staying Healthy When Improving Velocity Deficits

One thing to be aware of is that connective tissue such as tendons can get very irritated if a training program over-emphasizes velocity. In order to avoid pain syndromes and injury due to an excessive emphasis on movement velocity, athletes should maintain some slow, general strength type movements even if they are training to improve a velocity deficit. 

These workouts can be incorporated on recovery days, and should consist of bodyweight or low load exercises performed for a relatively high number of repetitions. Maintaining a general strength stimulus is important for all athletes, but even more so for athletes whose programs consist of a significant volume of high velocity training.

Another tool for angry tendons is blood flow restriction training. Say that you have tendons around the knee that are giving you problems, you can tightly wrap your thigh with something like knee wraps, and then perform sets of general strength work (such as hamstring curls and knee extensions with no load), and the restricted venous blood flow will help hydrate and heal your tendons, as well as reducing pain. Make sure to research BFR before you give it a try, and make sure that the wraps are tight enough to give you a good leg pump, but without causing any serious pain. Discomfort is OK, but sharp pain or intense pain is not.

References

• http://jbmorinsportscience.blogspot.com/2016/07/sprint-acceleration-force-velocity.html
• https://www.researchgate.net/publication/304253923_Effectiveness_of_an_optimized_training_using_Force-Velocity_profile_analysis
• https://www.researchgate.net/publication/287995954_Interpreting_Power-Force-Velocity_Profiles_for_Individualized_and_Specific_Training
• https://www.ncbi.nlm.nih.gov/pubmed/21364480
• http://journal.frontiersin.org/article/10.3389/fphys.2016.00677/full
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4689850/pdf/fphys-06-00404.pdf
• https://www.researchgate.net/profile/Jean-Benoit_Morin/publication/309965181_Very-Heavy_Sled_Training_for_Improving_Horizontal_Force_Output_in_Soccer_Players/links/58279a2608ae5c0137edff5a/Very-Heavy-Sled-Training-for-Improving-Horizontal-Force-Output-in-Soccer-Players.pdf
• https://pdfs.semanticscholar.org/4c2c/5695d2a32fe5e95b6c0696644c26ec6c06e1.pdf