FV Curve Profile for Acceleration Speed
What F0, V0 and Pmax reveal about how your athletes accelerate, and how to turn a profile into a training plan.
The short version
- One line, three numbers. As an athlete speeds up, the horizontal force they can apply falls in a straight line. F0, V0 and Pmax summarise that line.
- Power and direction win. Horizontal power and force orientation were linked to 100 m performance. Total force was not.
- Same time, different needs. Two athletes with the same 20 m time can have opposite profiles and need opposite training.
- You can measure it in the field. One sprint with speed-time data, body mass and height gives a valid profile. GPS training data can now give an in-situ version.
- Profile, prescribe, retest. Use the profile to choose loads and methods, then track whether the gap closes.
Every coach has seen it. Two athletes clock the same 20 m time, follow the same programme, and one improves while the other stalls. A stopwatch tells you how fast an athlete is. It doesn’t tell you why, or what to train next.
The sprint force-velocity (FV) profile fills that gap. It breaks acceleration down into the mechanical qualities behind it: how much horizontal force an athlete can produce, how fast they can still produce it, and how well they keep pointing that force forwards as they speed up. That matters because acceleration makes up most of a sprint. Even in the 100 m, the acceleration phase accounts for 60 to 70% of the race time for top-level athletes, and an even greater share of the 50 m and 60 m.
This article walks through what the profile is, what the research says about why it matters, how it can look completely different in athletes with identical times, how to measure it, and how to use it to coach.
What is the FV profile?
To accelerate, an athlete has to push their body mass forwards, and only the horizontal part of the ground reaction force does that. As running speed rises, the horizontal force an athlete can apply drops. Across a maximal sprint acceleration, that drop follows a remarkably straight line. This is the sprint force-velocity relationship, and it has been shown repeatedly in lab and field studies (Morin et al., 2010, 2019; Rabita et al., 2015; Samozino et al., 2016, as reviewed in Komino, 2022).
Because the relationship is linear, it can be described by where it meets the two axes, without having to pick arbitrary test speeds.
Two more variables describe the technique side of the profile. The ratio of force (RF) is the share of the total ground force that points forwards on each step. DRF is how quickly RF falls as the athlete speeds up. A flatter decline means the athlete keeps pushing forwards for longer (Morin, Edouard & Samozino, 2013).
| Variable | What it measures | What it tells a coach |
|---|---|---|
| F0 | Theoretical max horizontal force at zero velocity | The strength of the first pushes out of the start |
| V0 | Theoretical max running velocity at zero force | The athlete’s ability to still produce force at high speed |
| Pmax | Peak horizontal power output | Overall acceleration capacity, the top of the power arch |
| RF max | Highest share of total force directed forwards | How effectively force is aimed in the first steps |
| DRF | Rate of decline in RF as speed increases | How long the athlete holds a forward-pushing position |
Power and direction win
Jean-Benoît Morin, Pascal Edouard and Pierre Samozino tested sport science students, national-level sprinters and a world-class 100 m sprinter (9.92 s personal best) on a unique instrumented sprint treadmill. It measured horizontal and vertical ground force on every step, from a standing start up to top speed, at 1000 Hz. Each athlete also ran a 100 m on the track.
The results were consistent across both parts of the project:
- Horizontal force and horizontal power per kg were significantly correlated with 100 m performance (P < 0.01).
- DRF, the ability to limit the loss of forward force orientation, was highly correlated with top speed and 100 m average speed.
- Total force was not significantly related to 100 m average speed. Vertical force mattered for top speed, but not for acceleration.
- Force orientation and total force were not correlated with each other, so they are distinct skills that can be trained separately.
That last point is the key insight. On average over a 6-second treadmill sprint, the world-class sprinter produced about the same total force as the national-level athletes, and even some non-specialists. But because he oriented it forwards so well, his horizontal force was 12% higher than his national-level peers.
A further finding from Morin and colleagues (2012), summarised in Sims (2016), is that the velocity end of the profile separated elite from sub-elite sprinters more than the force end. This suggests that once athletes have adequate strength, the ability to apply that force quickly, at high speed, becomes the limiting factor.
The profile isn’t only a performance tool. It has also been shown to be a good indicator for orienting training and rehabilitation, and for flagging hamstring injury risk (Mendiguchia et al., 2014, 2016; Edouard et al., 2021, as cited in Komino, 2022).
Same time, different needs
Morin and Samozino (2016) profiled two elite rugby union players from maximal 30 m sprints. On paper they looked the same. They had similar maximal horizontal power per kg and similar 20 m times. Their profiles told a different story.
C Force dominant
Higher horizontal force in the first pushes, thanks to a higher RF max. But his RF fell away quickly as speed rose, so he couldn’t hold his forward lean.D Velocity dominant
Lower force in the first pushes, but he kept his force horizontal for longer. He kept accelerating for longer and reached a higher top speed.Give both players the same training block and at least one of them is working on the wrong thing. The profile shows each athlete’s gap, so training can target it.
Train the gap
The critical review by Sims (2016) brought together training recommendations for sprint-specific methods. Read alongside the profile, they give coaches a practical starting point.
| Profile finding | Training bias | Evidence-based prescription |
|---|---|---|
| Low F0 or low RF max | Horizontal force | Resisted sprints with a load causing a 10–30% drop in max velocity. Reps of 10–30 m, up to 250–350 m per session. |
| Fast RF decline (poor DRF) or low V0 | Max velocity, vertical force | Light resisted sprints at around 10% of body weight. Exposure to max-velocity running. |
| Low V0, mechanics stable | Supramaximal speed | Assisted towing at no more than 106–110% of max speed, reps under 40 m. Downhill sprints at 2–5.8° (never above 7°). |
| Low strength base | Tertiary methods | Strength, plyometrics and Olympic lifts to build force and rate of force development, alongside sprint drills. |
To help set loads, the review includes a regression equation for resisted sprinting on synthetic surfaces (Alcaraz et al., 2009): % body mass = (−0.8674 × % max velocity) + 87.99. Plotted out, it gives coaches a quick guide to the sled load for a target velocity drop.
Build the engine behind the profile
Sprinting itself should form the basis of the programme, but strength work shapes the profile too. Morin and colleagues (2015) found that athletes who produced the most horizontal force combined high hamstring activation just before foot contact with high eccentric knee-flexor strength. In their 2013 paper, Morin, Edouard and Samozino suggested two development paths for limiting the loss of RF: the hip extensors (glutes and hamstrings) for backward propulsion, and the ankle stabilisers for transmitting force into the ground.
Jump testing also shows that different strength qualities matter at different points along the acceleration. In 19 male sprinters, squat jump and countermovement jump height were linked to acceleration in the early stage, while an ankle-specific reactive jump was linked to the later stage (Nagahara et al., 2014).
How to test your athletes
The gold standard for sprint kinetics is an instrumented treadmill or a long run of force plates. Both are expensive and rare. Treadmill sprinting also isn’t quite real sprinting, because athletes are tethered from behind, run on a narrow belt and use a different start. A full acceleration over 20 to 60 m usually has to be stitched together from several sprints across force plates (Komino, 2022).
The good news is that coaches don’t need a lab any more.
| Method | What you need | Strengths | Limits |
|---|---|---|---|
| Lab | Instrumented treadmill or force plates | Direct force on every step, gold standard | Costly, rare, not quite like real sprinting |
| Field (single sprint) | Body mass, height and speed-time or position-time data from a radar, laser, timing gates or GPS | Close agreement with force-plate outputs, widely used in sport and research | Needs a dedicated session, a warm-up and full effort from each athlete |
| In-situ (GPS) | GPS speed data from normal training, over about two weeks | No testing session, uses real football movements | Needs enough true max efforts. A0 and S0 are close to F0 and V0, but not the same |
The single-sprint field method
Samozino and colleagues (2016) showed that a profile can be calculated from one maximal sprint. The athlete’s speed-time curve is fitted with a simple exponential model, then basic laws of motion convert it into horizontal force and power at every instant. F0 and V0 are taken from the intercepts of the resulting force-velocity line. This method is now used widely in both sport and research, and GPS units have been shown to be suitable for it (Komino, 2022).
The in-situ acceleration-speed profile
Morin and colleagues (2021) went a step further. They built an acceleration-speed (AS) profile from GPS data collected passively in normal training at a top-flight Italian club. Acceleration and force carry the same information, differing only by air resistance. So A0 (max acceleration) and S0 (max speed) mirror F0 and V0.
How close is the GPS version to the classic sprint profile? Komino (2022) tested 10 players with two 30 m sprints and a 45-minute, 7v7 small-sided game, all recorded with GPS.
Within a single sprint, the AS and FV methods agreed closely for top speed (V0 vs S0, r = 0.95). Both methods were also reliable from one sprint to the next, with average coefficients of variation under 4.6%. The in-situ comparison was weaker for max force. The reason wasn’t the GPS itself but a lack of hard accelerations at high speed in the 45-minute game. A reliable in-situ profile needs around 50 data points, including maximal accelerations at more than 90% of S0.
Take home messages
- Profile before you prescribe. Athletes with the same sprint time can need opposite training.
- Coach direction, not just effort. Cue a forward lean and a “push back” intent to keep force horizontal as speed rises.
- Train the gap. A low F0 calls for heavy resisted sprints (10–30% velocity loss, 10–30 m reps). A fast RF decline or low V0 calls for max-velocity work and lighter loads of about 10% body weight.
- Build the engine. Eccentric hamstring and glute strength support horizontal force. Reactive ankle strength supports the later steps.
- Quality first. Sprint maximally with minimal fatigue, since fatigue impairs force application.
- Measure what you can. Use a single field sprint, or GPS data with enough true max efforts.
- Retest. Re-profile after each block to check whether the gap is closing, then adjust.
References
- Morin JB, Edouard P, Samozino P. (2013). New insights into sprint biomechanics and determinants of elite 100m performance. New Studies in Athletics 28(3/4): 87–103.
- Komino P. (2022). Acceleration-speed profile in-situ in soccer: direct comparison with the classic sprint force-velocity profile. Master’s thesis, Université Jean Monnet, Saint-Etienne (supervised by JB Morin). Reviews Samozino et al. (2016), Morin et al. (2019), Rabita et al. (2015), Mendiguchia et al. (2014, 2016) and Edouard et al. (2021).
- Morin JB, Le Mat Y, Osgnach C, et al. (2021). Individual acceleration-speed profile in-situ: a proof of concept in professional football players. J Biomech 123: 110524.
- Sims L. (2016). Speed development: a critical review. MSc Strength and Conditioning assignment, Cardiff School of Sport. Includes Morin & Samozino (2016), Morin et al. (2012), Alcaraz et al. (2009) and Rumpf et al. (2016).
- Morin JB, Gimenez P, Edouard P, et al. (2015). Sprint acceleration mechanics: the major role of hamstrings in horizontal force production. Front Physiol 6: 404.
- Nagahara R, Naito H, Miyashiro K, Morin JB, Zushi K. (2014). Traditional and ankle-specific vertical jumps as strength-power indicators for maximal sprint acceleration. J Sports Med Phys Fitness 54: 691–699.
