Scott Salwasser, Texas Tech University
Scott Salwasser is one of the rising names in athletic speed development. If you haven’t seen the work he’s been doing with his team at Texas Tech that is circulating the internet, check out the video below, as it’s one of the premier speed training systems in the collegiate environment today:
Keep your eyes open for Scott’s athletes at the upcoming NFL combine!
With that said, onto Scott’s article on speed development and force-velocity profiling!
The force-velocity curve is literally a graphic representation of the interaction between force production and the speed at which it is developed. In practical terms, it is each athlete’s unique application of his/her strength. It is very similar to an autograph; everyone uses the same alphabet, but the handwriting is slightly different depending on who’s holding the pen.
This article lays out the process of developing individualized sprint and jump programming based off of Force-Velocity (F-V) profiling. I discuss methods of testing, how the results of the testing affect individual needs and programming, and finally provide case studies of the interventions at work. Please keep in mind, the specific context in this case is preparing American football athletes in a Combine/Pro Day scenario, however, the process discussed has transfer to any field or court sport athlete looking to improve sprint and/or jump performance.
My background in this area primarily involves force plate testing, initially as a Coach at Sparta Performance Science, and later using the same force plate technology at University of California-Berkeley with my football athletes. To this day, much of my understanding and application of the topics I will be covering has been heavily influenced by those experiences and I still consider force plate testing to be the gold standard as a method of athlete movement profiling. However, in my current role as Director of Speed & Power Development at Texas Tech University, I don’t have access to force plate technology and, like most everyone else, must rely on other methods of assessing my athletes.
Fortunately, there are a number of iPhone apps out there that I have been extremely pleased with in terms of their ability to be user friendly, while still providing high quality, useful data that has been validated in the scientific research community. I currently use MyJump2 and MySprint with my football athletes and the information contained in this piece is based on profiling done with those apps.
MyJump Force-Velocity readout
Additionally, I must mention, these are all just good tools that serve to complement a competent coach’s eye. Often the data provided serves to simply confirm what I may have already noticed by watching an athlete move or knowing what an athlete is good at and bad at. If you are in touch with your athletes, this information should rarely be shocking and will more than likely just provide objective, quantifiable data to support what you as a coach already have subjectively identified as strengths and weaknesses.
Finally, every movement has a strength and a skill component. Obviously, the primary goal of the interventions in this article is to improve the strength qualities that aid in improving sprint and jump performance. The other side of the coin is that these improvements are best paired with skill development to improve the technical component of movement, thereby allowing the athlete to unlock his/her full potential by utilizing the specific strength improvements to enhance their performance of the movement skill.
JB Morin and colleagues have done a fantastic job of describing the information produced by these applications and if you are unfamiliar with this technology or his work, I would first start there (as I did); in order to understand the information provided by and goals of Force-Velocity profiling.
As JB and colleagues found, athletes are imbalanced either toward Force or toward Velocity, and need an individualized, targeted training regimen to optimize their unique Force-Velocity curve and maximize their potential in sprinting and jumping.
On the surface, it seems simple; on one side get stronger, on the other side move faster. Doing this would certainly be better than just administering a “one size fits all” program to everyone equally. However, I have found that it goes much deeper, and there are underpinning qualities that serve to significantly enhance both of these variables optimally. Additionally, there is an obvious difference between addressing the needs of a vertical jump and a sprint, even if the athlete tests out to have the same imbalance on both.
Jump Assessment by Force Need
I will begin by discussing how to fix the jump. Force can and will be enhanced by improving absolute strength, however, we must remember the context of the testing. Standing jumps are explosive movements, therefore, what we are really after is concentric rate of force development (RFD).
Furthermore, when we are talking about average force development (which is the average amount of force throughout the jump as opposed to peak force, which would be the highest amount of force at a specific moment in the jump) to yield a high value we need a high force value early on in the movement and no “leaks”, or dips in force production, over the course of the action. The qualities that go into improving “Force deficient” athletes in jump profiling by addressing the aforementioned needs are as follows:
- Starting strength
- Accelerative strength
- Moderate load/high power speed strength
- Reactive strength
- Isometric strength and trunk stability
Starting strength is the ability to rapidly overcome a dead stop. In order to yield a high force value in the jump, starting strength must be trained as it will contribute to a sudden spike in force production immediately prior to the onset of movement. An example of an exercise I utilize to train this quality is a seated box jump (preferably without arm swing as seen to de-emphasize momentum).
The next quality, accelerative strength, is the ability to continue to apply a high level of force once movement begins. I train this quality against heavy loads, but rather than simply looking to increase weight, we focus on moving the bar as rapidly as possible. An example would be a heavy squat at .5 to .7 m/s average velocity (as measured by a tendo in our case), rather than a true max effort lift, which might look more like .3 m/s. This works well in a Pro Day scenario as well because I decrease the risk by not putting the athlete under a maximal load.
Strength-speed and speed-strength are similar, and in this case primarily depend on exercise selection. When we are doing a traditional strength movement, such as a squat, I use the Dynamic Effort method with accommodating resistance, looking for .8 to 1.0 m/s in average velocity and am obviously training Strength-Speed.
When we are doing Olympic variations for Force need athletes, I prefer to go from the hang, and I look for 1.3 m/s or greater, again average velocity, because I am putting a premium on initial and sudden force production, and in this case we would be training speed-strength.
Reactive strength is the ability to utilize the stretch shortening cycle to enhance RFD and explosive strength. Plyometrics are my favorite means to improve this quality, however, again we must consider the dynamics of what we are trying to improve: A single maximal explosive effort. Therefore I prefer a depth jump progression. Additionally, MyJump has a reactive strength test that works well to select optimal drop height.
The last two necessary qualities, isometric and trunk strength, are in a way related. I view isometric strength as a bridge of sorts from eccentric to concentric, just as the trunk is a bridge between the lower and upper extremities. The purpose of both is to transfer force, which will minimize wasted energy, or “force leaks”, and ensure that all tension created in a movement contributes to the output.
I train Isometric strength primarily with ISO overcoming rack presses or pulls against an immovable object, and trunk stability with anti-movement variations such as rollouts and suitcase carries. All of this is obviously spread out over the course of a microcycle, mesocycle, or even the entire macrocycle (usually 8-12 weeks for Pro Day prep).
Concurrently with the strength development, we will practice the skill we are looking to improve; in this case, a single maximal vertical jump on a Vertec under testing regulations. The emphasis, technically, is on being a spring and being violent and sudden out of the bottom, which as you can see from the intervention categories/targets mentioned above, is where these athletes may struggle.
Sprint Assessment through Ratio of Force (RF)
To this point, the article has centered around jump development, and while obviously many of the strength qualities will carry over, there are two main differences that will need to be addressed between jumping and sprinting: firstly, the horizontal aspect of sprinting, and secondly, the increased skill demand of sprinting.
An athlete that needs Force on the jump will more than likely need Force on the sprint and therefore many of the strength qualities mentioned before will have carry over, however, the horizontal aspect must be addressed. MySprint gives values for ratio of force (horizontal vs. vertical) and decrease in ratio of force (loss in ability to apply horizontal forces during acceleration; the longer an athlete can continue to apply horizontal forces, the longer their acceleration period, and the higher their top end speed will be); often I will find that athletes have respectable Force and Force/Bodyweight ratio values compared to peers but struggle to direct that Force horizontally.
To address the ratio of Force (RF), I have become a big fan of the heavy sled work that has been popularized in the recent literature. We use the recommended 80% BW as a guideline, but what I really look for (thanks Cam Josse) is the 50% decrement in Velocity. I find that this improves not only special strength for acceleration, but also offers potent technical potentiation for total body lean and push mechanics.
To address decrease in ratio of force (athletes that bail on acceleration mechanics too quickly), I contrast the heavy work with lighter sleds, looking for roughly 10% decrease in velocity, which I find occurs around 15-20% BW over acceleration distances (<30m). This will also help athletes that need velocity as, in order to reach a higher velocity, one needs to be able to accelerate further/deeper into the race.
My favorite treatment for velocity need athletes, however, are flying sprints. This allows them to practice the gradual acceleration they need along with relaxation and high velocity sprinting exposure, and this obviously bleeds over into the skill realm.
By comparison, athletes that need force require start/early acceleration development skill-wise. The particular group of NFL hopefuls in this case study all tested out as needing Force (my thoughts as to why come later) and have three speed days a week, one acceleration, one absolute speed, one by need (which as mentioned earlier, since they are all Force-need guys, is a start day).
Jump and Sprint Assessment by Velocity Need
However, should any of them have tested as needing Velocity, obviously a different set of qualities would need to be developed in their training. As mentioned with Force, it is more complicated than simply moving fast, as many of the treatments for Force deficiency involved moving fast.
What we are specifically looking at with an athlete that needs velocity is the ability to build momentum over time and increase force over the entire movement ROM, especially at the very end where the highest velocities are experienced. Keeping this in mind will guide our prescription for athletes needing velocity. The particular qualities addressed for an athlete needing velocity would be:
- Mobility and a healthy range of motion
- Low load, high velocity speed strength particularly through the use of ballistic movements
- An emphasis on peak rather than average velocity on loaded movements
- Posterior chain strength and rhythm/timing
For mobility I would emphasize soft tissue quality, dynamic stretches and activation movements emphasizing motor control over the specific joint ROM.
For loaded strength movements, emphasize those that require stability and tension over an exaggerated ROM such as RFE split squat. Light ballistic exercises such as MB throws would be my choice for developing speed strength with these athletes as they rely on a buildup of momentum and emphasize a high release velocity in order to achieve the greatest high or distance. For explosive strength movements such as Olympic lifts, as I mentioned, I would favor peak velocity over average velocity because that is the important quality we are trying to develop, and I would prefer to go from the floor with these athletes to give them a greater ROM to accelerate the bar and reach the highest peak velocity possible.
Additionally, snatch might be a better choice for velocity athletes (higher peak velocity) and clean for force athletes (capable of greater loading). The hip extensors finish the jump in the critical take off velocity zone and would receive particular attention through targeted exercises such as hip thrusts.
Reactive strength exercises emphasizing multiple responses, rhythm and timing, or the ability to carry momentum, would be my choice to fill that slot, such as repetitive hurdle hops.
Finally, overspeed jumps such as band assisted jumps would certainly have a role as lightening bodyweight would allow the athlete to practice producing force at a greater velocity; also, possibly even something such as an approach jump. Skill wise, a greater emphasis would be placed on greater arm utilization and possibly loading deeper, both of which will allow the athlete a greater time to apply force over and potentially a greater takeoff velocity.
Eccentric Training Considerations
Intentionally, I have not spent much time discussing the eccentric component, which is a critical component to success. This is primarily because while the force plate gives eccentric values, the iPhone apps do not, so I don’t have objective data on this measure. However, it (eccentric) clearly plays a role in both sprinting and jumping, and therefore must be trained for.
In sprinting, good eccentric stiffness is crucial for a firm, crisp forceful foot strike with minimal ground contact time. In jumping, the eccentric phase serves to “supercharge” the concentric jump with extra potential energy and thus output. Additionally, in the context of this article (Pro Day prep), eccentric strength is essential to deceleration, which is a necessary quality to perform well in the two agility tests (pro and L).
In my program, for every acceleration based movement (concentric emphasis), I try to do a deceleration based movement (eccentric emphasis). Just a few of many examples are high altitude landings with jumps, heavy eccentric lowering for resistance overload, and velocity overload exercises like KB swing power bombs. You can’t drive the car faster than the brakes will allow you to stop, and while I haven’t mentioned this much for the aforementioned reasons, it is a crucial aspect of my program.
This case study is a perfect example of why you never really know an athlete’s needs until you assess. The 4 athletes that were exposed to this protocol all tested as needing Force. However, to the uninitiated, they appear completely different. Two are wiry skill position athletes that, at a glance, would make sense why they need force; they don’t have great output on traditional strength movements, and they are very fast once they get going but, relatively speaking, they need to clean up their start.
The other two, however, are “meathead” big skill athletes that can move the entire weight room on traditional measures of strength, such as squat, bench and deadlift, and before you accuse them of not being explosive, this includes Olympic variations. On the jump, however, they each had a “leaky” trunk, functioning sub-optimally (dysfunction) that prevented optimal force transfer. On the sprints, neither one could convert their tremendous force potential from the vertical plane to the horizontal plane, as evidenced by their poor RF (Ratio of Force) and DRF (Decrease in Ratio of Force) values.
The rationale for the X’s & O’s of these athlete’s training programs is described above. As you can see it is simply a unique and targeted application of the classics: sprint, jump, throw, lift. This is the first time that I have constructed a program exclusively based off of F-V profiling in the public sector, and although the sample size is small, the results are none-the-less impressive. Bear in mind that each of these athletes were scholarship football players at a “Power 5” institution; which on one hand that means they are genetically gifted and adapt well to stimuli, but it also means that they are starting their pro day prep from an already high level and improvements are harder to come by as they are far from untrained.
At the writing of this article (7 weeks of training, not yet having completed Pro Day), just speaking in terms of the qualities addressed in this article, all 4 have improved between .1 & .2 in the 40 yard dash (Brower laser timing system), and 3+ inches on Vertical Jump (Vertec). Please stay posted, as in the near future, I’ll write a follow up piece detailing the final results, outlining my template, where the interventions mentioned fit into my system, and retrospectively reflecting on the entire process moving forward.
About Scott Salwasser
Scott Salwasser is currently the Director of Speed and Power Development at Texas Tech University, where he works exclusively with the Football program. He served previously on the strength and conditioning staffs at UC Berkeley, Sparta Performance Science, University of Louisiana-Lafayette, Sacramento State and the Oakland Raiders. He competed nationally in Weightlifting as a graduate student at Sacramento State, and played intercollegiate Football as an undergraduate at UC Davis. He has a Master’s Degree in Kinesiology and is CSCS certified, among other distinctions. He and his wife Katie have two daughters, Stella and Charlotte.
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