By Carl Valle
At the elite level of sport, the choices we make as coaches become more important and the risks and rewards of our decisions have higher stakes. Force-velocity profiling that leads to changes that matter is worth our investment.
Profiling athletes is growing, thanks to much of the research coming out of France and New Zealand. Yet the force-velocity profile is misunderstood greatly, even among sport scientists who often look for optimal windows of loads to prescribe. The programming of a force-velocity quality is far more complicated than the speed of a movement or weight on a sled. The concepts behind force-velocity curves also have a few contradictions that make it difficult to program training when we follow them too closely. This article clears up these contradictions.
Force-Velocity Profiling of Strength, Power, and Speed
One of the most popular articles I’ve shared had a chart of exercises and segments of velocity in a sprint repetition. The chart listed the 10m splits from 0-70m, illustrating how various exercises influenced improvements in each zone. While it was certainly a practical way to use a training inventory, the force-velocity curve in sport is mythical to some circles of coaches—to the point that everyone needs to step back and take a closer look at the science. According to Science for Sport, a leading sport science resource for coaches, the definition of the force-velocity curve and theoretical concept in performance is the following:
“The force-velocity curve is a physical representation of the inverse relationship between force and velocity.”—Science for Sport
When we talk about athlete force-velocity profiles, most of the discussion is distilled to the bar’s optimal load and the timing of when a transfer is likely to happen in the weighted lifts based on an individual’s size. Sometimes there’s a pointless argument about when strength-speed and speed-strength are appropriate for baseball players in training–all nice in theory but useless for real-world results.
The promise of the force-velocity curve is this: training at specific points will elicit better results with athletes. And this is completely false. While it’s true that specificity of training, either technical or load, will carry over better, the composite of all training is the reason some programs succeed, and some seem to struggle.The force-velocity curve’s promise–training at specific points will elicit better results–is false Click To Tweet
Much of the problem with the force-velocity curve is that training is difficult to isolate. What we do know about power is that, without a sufficient strength level, it develops slowly. Robert Newton provided a succinct presentation about the value of maximal strength as a prerequisite for power. But some team sports still resort to other less effective options like silly balance exercises and ridiculously light loads.
Other nervous system adaptations are part of the equation when programming speed and power, and many programs naturally address the force-velocity curve indirectly. For example, do athletes need anything beyond maximal strength and sprinting to improve? While the answer is that athletes may need more than heavy squats and fast sprints, they can meet most of the requirements for performance with a handful of exercises and training modalities.
Over the last few years, the force-velocity curve has been dissected even thinner with the idea that weightlifting derivatives have a subset of velocities. But does a snatch from blocks instead of a clean from the floor determine who wins a 60m dash? A lot of questions must be answered or at least explored.
Vertical and Horizontal Force-Velocity Profiling and Beyond
With their athletic speed and profiling research, France has had a small surge in highly thoughtful analyses of performance. Morin and Samozino modeled horizontal speed and ballistic push-off abilities training prescriptions. The information was both contemporary and innovative, but it was still an outline and not the full picture. It’s the coach’s job to bridge the gap between observational analysis and applied training. The research was a great template to address, but scientists can’t solve all the problems and do all of the dirty work.
More than just jump power and horizontal speed or force obviously matter for athlete development. The model proposed by the two authors is a tremendous step forward for the performance community, but it’s far from complete. Several other experts have profiled the body deeper, down to the individual muscle group in a single-joint movement. Profiling consists of one part categorization and another part prescription. While reading about grouping athletes by select abilities is interesting, we have to be able to use the information collected in group training in a practical manner.
Motor learning must be connected to force-velocity profiling as athletes with different physical abilities have additional combinations of mental or motor approaches to training and testing. Knowing someone’s force and velocity abilities is a different story from having the ability to teach them. Coaches should explore the interaction of different talents and training responses with the ways instruction can differ. Profiling goes beyond force and velocity, it’s a part of every athlete’s characteristics.
Why Profiling is Gaining Popularity but Not Gaining Ground in Sport Science
With all the current research, coaches would think they were entering the next evolution of sports performance. While the research is compelling and very strong, force-velocity profiling is not taking off due to the logistical constraints of training in groups. Sport science is promising the potential to better individually prescribe training more tailored to an athlete’s abilities, but read world challenges constrain the application and impair these opportunities.Force-velocity profiling is not taking off due to the logistical constraints of training in groups. Click To Tweet
The major problem with profiling is that individualism is hard to plan when logistical needs like practices, staff, and facilities are designed to manage groups, not provide unique experiences. A coach may have the ability and time to write dozens of unique workouts, but coaching them creates chaos when everyone is on individual timelines. Also, most force-velocity individualism is unlikely to stem just from an athlete’s talent.
The specific sport often drives force-velocity patterns based on the demands of practice and sometimes the game’s culture. Typically highly skilled sports such as soccer and basketball have major force level deficits, but because it’s acceptable to leave talented athletes alone and let the cream rise, injuries plague the professional leagues.
Profiling the force-velocity curve also requires instruments and expertise that many coaches are not aware of, unable to do, don’t want to do, or don’t have time to do. Profiling requires careful testing and training time to make a difference, two factors that may inhibit adoption.
Profiling for Talent Identification and Athlete Development
We also need to interpret youth talent identification—what is required to develop those who are gifted and those who don’t have the same genetic abilities. Speed is very trainable, but a mule will never win a Kentucky Derby because DNA has limits.
As athletes age, training becomes an opportunity to cement their talents. Profiling can spot athletes who are gifted and raw, but it’s also subject to a lot of interpretation errors because of maturation factors. A 14-year-old boy has a chronological and biological age as well as a training age.
Spotting talent is not identifying the kids who have the best force-velocity profile for their respective sport. It’s about understanding that all potential is relative. We still need to see what they can do on the field. Unfortunately the field is overvalued; athletes who lack training and specific force characteristics will be kept off the field by injuries if they are allowed to tour instead of train. Currently in the US, travel teams are increasing the problem of training age matching chronological age because athletes spend more time competing than preparing.As athlete development continues, force-velocity profiling becomes more important. Click To Tweet
Athletes at higher levels, including professionals, can continue to develop. Athlete development doesn’t end when one signs their first pro contract. It never ends since an athlete can always train better. As development continues, force-velocity profiling becomes more important because chances for growth become narrow. It’s not that youth athletes don’t benefit from force-velocity profiling, it’s that strength usually solves power demands when beginning a performance enhancement training program.
How to Profile Athletic Motions and Strength Training
Most of the information on force-velocity profiling covers linear speed, vertical jumping performance, and barbell exercises. My problem with this limitation is that interventions outside of general maximal strength and reactive work from sprinting or short amplitude plyometrics are not teased out from profiling. Force-velocity profiling is only a volume knob that suggests which loading may provide a strong enough stimulus to improve outcomes of the tested task.
Several papers have revealed insights into sprinting, jumping, and weight training for testing force-velocity profiles. Very few, if any, made a case for using the data over time to create athletes who are superior to their respective peers.
Video 1. Elastic profiling techniques, popularized by the Eccentric Utilization Ratio, start with a squat jump to see how an athlete creates force from a static position. Even small motions create a false testing result, especially if there’s very little isometric training in your program.
Testing must have a sound plan or decision-making tree that concludes with a worthwhile expectation. A worthwhile change is one that can impact the game, not just show statistical significance. While many studies showing statistical significance are valid, some of these papers may not be useful when coaches are shopping for a bigger bang for their time and effort buck.
Profiling Strength Training
Most of the data presented in strength training literature comes either from isokinetic, single-joint testing or from squatting. While I’ve not seen anything of interest covering unilateral multi-joint actions, I suggest using the one-rep estimation calculations cautiously from Jovanovic and Flannagan. Not all exercises trend well, and loads above 90% tend to model strangely and uniquely with athletes. The better skilled and advanced the lifter, the better the data looks.
Athletes with poor training history should not be using load velocity tables or estimations of one-rep maximum. When testing, incremental loads will create an exercise profile output based on the speed of the movement and the load. Most coaches will test 4-5 sets of an exercise and then perform a light statistical analysis. The first bout of testing may reveal ability deficits or preferences, and three testing periods will show a trend.
Isokinetic and other tests only have value because they can isolate a potential issue relating to past injuries or screen out possible risks for new injuries. Some right and left comparison tests are possible with both types of testing (free weights and isokinetic exercises), but most of the studies looked at general characteristics of bilateral movements. Asymmetry assessment is very tricky, and I recommend reading more at Researchgate.
Profiling Jump Performance
In research studies, jump tests are mainly vertical, so in the literature, we find similarities to squatting. Horizontal jumping tests are difficult because the skill and instruments needed for repeated hops and bounds limit the population and availability of the data. Unrepeated bilateral jumps, on the other hand, are easy to see on a force plate.
Simple options are to test bounds for distance and to use a specialized jumping force plate with jumps. Jump tests for distance are useful, but the repeated nature of bounding removes landing techniques that either game the distance or cause injury. I don’t suggest bounding for distance when athletes are more than 100 kilograms, and all athletes must be well-trained before testing is appropriate. With many jump tests, athletes are susceptible to fatigue and movement strategy, so monitoring improves the data’s validity when combined with the assessment process.
Coaches usually analyze jump squats and loaded jumps for peak concentric power or force—we glean very little eccentric activity. While it’s great to see the performance characteristics of propulsion, most coaches who work at high-level sport are concerned about injury rates, especially those working with teams. Comparing jumps to weight training has a very strong relationship because the movement patterns are similar, and jumping has less technique influence than sprints. We can include other tests for comparison, like the Reactive Strength Index as well as the Eccentric Utilization Ratio.
Profiling Linear Speed
Due to the complexities of sprinting mechanics, speed requires more interpretation than jumps or strength training. Errors in running form may interact with force-velocity profiling, and force-velocity relationships may create reflexive mechanical responses. Instruments that capture force data are blind, meaning the information collected doesn’t tell the whole story. So extrapolating force without kinematic information must be taken with a grain of salt.
Acceleration and maximal velocity are absolute and are relative measurements to each other and compared to populations and body sizes. In addition to weight, we can also argue for comparing limb lengths, especially with Usain Bolt’s success over the last decade. While horizontal and vertical forces are factors, the end value is improving the speed from point A to point B by using modalities to improve times.
Video 2. Simple speed testing with splits provides enough information to understand how an athlete accelerates and if they hit a high maximal velocity. Profiling speed is easy. It’s about knowing how the weight room interacts with sled load rather than evaluating horizontal forces.
Most of the success from force-velocity profiling comes from knowing what loads to use in exercises; selecting training modalities is the precursor. Athletes who accelerate poorly compared to their maximal speed capabilities are rare, and usually these athletes are under-trained in the weight room.
Athletes who have great acceleration but poor maximal speed are likely to be larger athletes or under-skilled runners. Getting only force-time data from instruments in speed testing creates an incomplete picture. Horizontal force is only valuable if it leads to horizontal speeds that have real-world value.
Since coaches train several components at the same time, it can be very difficult to determine a cause and effect without a lot of work sifting through the training data. Testing the three areas of performance and training doesn’t take a huge amount of time and can be embedded into what you’re already doing. The frequency of testing or profiling force-velocity abilities should be similar to the principles of any performance test, and you should repeat the assessment to the rate of expected improvement.
How to Prescribe Training from Comprehensive Profiling
From a coaching perspective, prescription after force-velocity profiling is more complicated than testing—but programming is not the problem. Often the baggage of sport culture is the reason athletes need to change their force-velocity profile. All professional team sports, and now more Olympic sports, cater to competition frequency and length, thus reducing total preparation time. While the challenge is to find access to training, the force-velocity profiling testing and the prescription process may be a viable solution to help glean more from the training time that is available.Force-velocity profiling may help glean more results from available training time. Click To Tweet
In the past, some coaches came up with pragmatic “mantras” for athletes who were either too weak for their speed or too slow for their strength. Jumping is specific enough to merit a summary of strength and velocity qualities that need attention. Elastic and reactive modalities have been included for athletes who have big squats but little verticals. Athletes with poor training ages just need to be on a program, intermediate athletes need challenges in all areas, and advanced athletes will benefit from extremely individualized programs.
Those who truly need prescriptions are the advancing athletes who risk either injury or an impossible time allocation challenge if they spend more effort to raise their general abilities or capacity. When an athlete hits the ceiling, a force-velocity prescription may break the stagnation or plateau. Instead of programming phases based on classical training theory, coaches can prescribe tailored workouts based on guided data and sport science.
Velocity Based Training (VBT) has a place in training prescriptions. Most successful VBT applications maintain quality while leaving physical and time resources available for areas where the athlete needs work. Most athletes can succeed from addressing a weakness rather than fighting their genetics, though this is debatable for coaches who believe in training to the athlete’s strength. The goals of VBT and force-velocity profiling are to add more precision to the training, not to disrupt what is already working for the athlete and coach.
Most of the time, a coach looks for general training in the weight room. They use jumping exercises to help with speed on the court or field and height when making a play in the air. Speed is the ability to apply the correct force in very short time frames. Jumping is about overcoming gravity based on the athlete’s anthropometry. Knowing how to shift force-velocity abilities from both loading and exercise selection can help athletes become more athletic, provided the rest of the training requirements are accomplished in concert.
Is Force-Velocity Profiling Worthwhile?
It’s likely you’re already profiling force-velocity abilities without realizing it. Most coaches will record different best performances in testing or during training and use that information to decide how to change an overall program or tailor individual training. Coaches create a system, look at how the overall group fairs, and proceed to adjust the next year with small changes.
Unfortunately, using only the group average could mean top athletes won’t respond or that everyone will improve a little–but nothing impressive occurs. To take advantage of force-velocity profiling, coaches must have athletes at a base strength level and then decide if the extra effort will be worthwhile.
In sport, force-velocity profiling needs to show up on the watch or tape, as improvements may help reduce injuries. In the research, nothing of note shows that force-velocity development does anything specifically for injuries beyond some eccentric studies and isokinetic testing. Currently, most of the force-velocity work has been on performance, but interesting return-to-play information is growing.
My approach to force-velocity profiling isn’t very complicated. It’s brutally simple and honest: use force-velocity profiling to assess athletes who are coming into your program and use it when they start to stagnate. Most programs address force-velocity demands from a general training design, but drilling down further is now possible and will benefit those who have limited time resources.