By Carl Valle
I was blown away last year by the outstanding work of George Petrakos, who wrote a wonderful series of articles on resisted sprinting that forced me to rethink what is possible with my own athletes. While I have always experimented with loading with resistance sprints, the standard that George shared for fine-tuning resisted sprints was so high it took me nearly a year to find a better way to improve athlete speed.
What I discovered was that a lot of attention to detail is necessary to maximize an athlete’s abilities, and a time or place exists to break conventional wisdom. In this extensive article, I will build on work shared earlier and take a deep dive into more research and my own data with the 1080 Sprint.
The Evolution of Resisted Sprinting
For years, I have advocated moving away from percentages of body weight to velocity changes with sled or resisted sprints, but the scientific community evolved the prescription approach even further. Maximal resisted sled load, or MRSL, is now the new metric of choice, but is it the final destination or the midpoint of acceleration training? Just to make sure everyone is on the same page, according to George Petrakos and colleagues, the definition of MRSL is:
“The maximal load at which the athlete remains in sprint acceleration from 10 to 20m in a 0-20m resisted sled sprint.”
As you can see from the definition, we are analyzing the velocity of the athlete from 10-20 meters at the two segments from 10-15 meters and 15-20 meters. When the last 5-meter segment drops in velocity so significantly that the athlete actually decelerates, the load is considered above threshold. What makes this special is that it evolves the precision of the loading beyond just a percentage of time; something only a few coaches were implementing.
I have used my timing system to get splits based on the static loading of sleds, but it was always a compromise: I could only tackle one part of the acceleration phase at a time because loading was not variable. I feel that the Spaniards that came up with this metric innovated brilliantly, but the guidelines were too vague to be satisfied with just loading based on speed and weight. I found a few problems with the MRSL approach in the practical settings and with the science behind it.
The promise of MRSL is to use loads based on the adaptations that are programmable, such as different force characteristics. If using velocity to program resisted sprinting is analogous to a magnifying glass, the MRSL is like a microscope. Still, thanks to other researchers and coaches who are able to improve athletes, we can go deeper—not just observe what makes them great.
Much of the research I have seen is on isolated variables, which is useful, but there’s always less efficacy and carryover of the research when we try to apply it. I read the research again and came to the same conclusions as before; some of the research is simply biased because the subjects are populations that respond easily to nearly any stimulus, and coaches want more targeted solutions.
Athlete Force – Velocity in Sprinting
Lately, a lot of excellent research is coming out with more instrumentation, but the interpretation and conclusions need a lot of work before we can start applying the findings. The main reason we are seeing very heavy loads used is that it works acutely for many undertrained athletes who are either weak or rarely exposed to sprinting. I am biased in that I care only about what works best; I do not want just the improvement of a few soccer academy athletes who have survived with balance exercises and banana hurdle drills. My focus is on the most potent and effective training, regardless of the modality.
We are now seeing some great scientific analysis on foot strike, such as the studies on horizontal, vertical, and lateral forces during sprinting. The problem with descriptive analysis is that it can’t always lead to prescriptive analysis with coaching. The lesson we have learned by studying stride frequency and stride length when those measures were in vogue was that getting people to improve those measures is a different ball of wax altogether. You can only glean so much from research, but the key to applying sport science is knowing what to experiment with and what studies simply have no value. With horizontal and vertical forces, not much has shown up in real-world programming besides an attempt to target muscles specifically.
Even contact times and flight times need deep analysis of other data points to draw definitive conclusions. Increasing forces is important, but the way those forces are administered and the way that coaches load and teach is the reason we can’t believe that studies are going to change world records in sprinting anytime soon. The fastest sprint splits in acceleration were set in the 1990s; a reminder that glorified bodybuilding of any muscle isn’t going to create the next set of champions. Much of the results come from having healthy talent and, all too commonly, those talents simply wash out bad programs.
What we can learn from force analysis in sprinting is how loading modulates different characteristics of an athlete’s anatomy and physiology. It doesn’t tell us how to train better, but it does hint at the reason certain protocols may influence change. Again, take all of this with a grain of salt. An appropriate way to look at force analysis during linear sprints is to ask why athletes are more likely to respond faster to personalized training, and that is about it, folks.
I have found some athletes have been loaded inappropriately because force data was incorrectly interpreted and valuable time was lost training a symptom of a problem rather than the root issue. An example of this was found with ankle plantar strength failing to catch up to the other areas of the body. Another example was an athlete evaluated to have the same squat strength with conventional 1 RM testing. He achieved those scores in his previous program, during heavy training periods while the new training season was testing him fresh.Speed is too valuable to leave to chance. You need to measure it with a serious approach. Click To Tweet
All of this may sound picky, but when you are dealing with .08 seconds in a 20m, this could be the difference in getting a shot off in the English Premier League and getting tackled. Speed is too valuable be left to chance, and if you are not measuring it with a serious approach, someone else will, with a better chance of improving their athletes.
Prerequisites in Acceleration Development
I care about how fast an athlete can go from point A to point B, and the details are only important if they can improve the group of athletes I am working with. You can recruit talent, keep talent happy, or develop the talent you have. Getting all three accomplished is ideal, but to recruit and keep talent in the long run, you eventually have to show that you are making them better instead of just getting them at the peak of their career. In team sport, much of what we do is preserving the talent the athlete has and fighting aging and injury, but it’s still a fight to sustain performance. In track and field, you try to maximize talent, or constantly get faster somehow.
It is tempting to get excited about the possibilities presented by new research on resisted sprinting, specifically MRSL. Before we continue to push into advanced territories, let’s focus on what is probable, not just possible. As training opportunities seem to dry up because of competition demands, it’s better to focus on bang for your buck and smarter use of resources than be fancy to feel smart or appear advanced. Exotic periodization schemes were great for hammer throwers in the 1980s but, for the most part, they can’t fix the problems we are seeing in sports leagues today. A realistic set of priorities in acceleration is the following:
Conventional Strength – Is a progressive overload strength program being implemented with the athlete’s training? A simple lower body strength program that addresses raising general maximal strength in a sane manner will improve acceleration. Coaches should not chase the best maximal strength program, but the right program for their athletes. A combination of double- and single-leg programming will exploit neuromuscular advancements like bilateral facilitation and other high level adaptations.
Some research is available hinting that specific exercises are better than others, but before we get too excited, remember my point earlier that the best acceleration of all time with humans has still not been beaten by contemporary athletes. A holistic program in the weight room or jump training on the track is better than searching for the magic bullet exercise.
Periodizing Speed Appropriately – Exposure to sprints does add up over time without shutting down practices for team sport, but Olympic sport must prioritize speed when planning workouts. It is not a compromise to coordinate practices so that they are not just tactical and technical; it is a way to improve the outcomes that team coaches want.
Sharp and smart practices are about knowing how to load the training week, and sports teams can find ways to sprinkle speed without having a team coach think you are robbing them of time. If team sport coaches are not cooperative, then they are responsible for losses attributed to any claim of not looking fast on the field. Track and field is a little bit different but, with the modern diamond league competing in several continents, even sprinters are finding training time reduced.
Video 1: Acceleration early in the off-season training period helps determine if past injuries or bad habits are lingering from a long season in team sport athletes. The use of video and 1080 Sprint data can help smooth out problems after a few weeks of focus.
Injury Factors – A speed program is usually limited by the health of the athlete and their tolerance to loading, so while it’s great to get specific with any type of training, the ability to train consistently over a long period without compromise is usually more effective than the best program on paper. Eccentric training and monitoring can help create a buffer between risk and actual injury by adding more precision to the training load. In addition to loading, some biomechanical and anatomical evaluation is important because, as loading increases, the risk of injury will increase as well. The body adapts specifically, so an Achilles tendon is different than a hamstring and a knee is different than a shoulder. When doing medicine ball training, a hip extension group may adapt fast, while a rotator cuff group might lag behind.
The list above is not revolutionary by any means, but it’s a reminder that it’s better to polish the basics now than clean up an advanced mess later. If an athlete has a sufficient training age and has started to hit a ceiling for advancing in speed development, it’s worth taking acceleration to high-resolution instead of foundational levels.
High-Resolution Evaluation of Acceleration
Before you begin creating a program, you have to ask the simple question of what is holding an athlete back from improving, far in advance. Acceleration should not be distilled into the resisted runs that should be used, but coaches should look at the big picture with regard to time and other priorities. As the athlete ages and advances, it’s less likely a coach will change things; instead, they’ll likely feel that what they are doing is more valuable because the athlete is more advanced. When evaluating an athlete, remember to see how factors influence time and space to ensure you are not overthinking things.
Analyzing the data has three levels of depth: the shallow or obvious variables, the deeper trends, and, of course, the deep dive to pay dirt. The more data you have, the more potential to find the winning variable that can be modulated for change, but that also decreases the sustainability of good workflow in training. Too much noise can create paralysis with coaches and athletes. Not enough data and the training prescriptions are blind.
Since adopting the 1080 Sprint system, I have changed to focus on immediate feedback options of the equipment. Combining it with other tools can give you a true evaluation of what needs to be done in training, as time is such a premium.
Velocity Peaks – How fast an athlete sprints over the same distance will be a positive change in body velocity—the goal in speed training. Loaded acceleration, regardless of the absolute numbers, is a game of getting more speed over time. Instead of trying to just hit splits, an easier way is to see if athletes are hitting velocities sooner. In race modeling, the athlete needs to hit a greater peak without compromising the total time because of fatigue. Interpreting the velocity peaks requires analysis of fatigue, training load, and, of course, technical ability. It’s OK to see a drop in speed from time to time, but eventually a positive adaptation (improvement) needs to show up.
Step Power and Force – I have looked at force analysis (peak and average) to see how athletes are improving or responding to loads. While it’s foolish to artificially lump athletes into categories they succeed in, athletes with poor profiles in one area are usually gifted in another. Addressing weaknesses without blunting talents is a delicate process, but small doses of speed and strength “antidotes” are welcome solutions that should transfer if implemented well.The real-time view with the 1080 Sprint software is like a brain scan to speed training. Click To Tweet
Step Count and Shape – You can collect stride length parameters via video analysis, optical runways, and the 1080 Sprint. I have found that simple step counts at distances are primitive, but they work. In addition to steps (length and frequency), the shape of the steps can identify right and left symmetry issues and whether gross stride dysfunction is apparent. The real-time view with the 1080 Sprint software is like a brain scan to speed training. In my experience, the most valuable information comes from the step charts that the software provides.
Body Lean Patterns – Shin angles and body angles tend to smoothly become more vertical over time and distance, but in some acceleration work this may not occur. The heavier the load, the more kinematic changes occur, and this may be acceptable if an overall improvement happens with body speed. Still, long sprints with loads that lock in a body lean are more problematic for sprinters, and also create stereotypes for field and team sports.
Contact Times and Contact Pressures – Using pressure mapping and research-grade wearable technology, coaches want to see contact times decrease without compromising length. More propulsive forces transmitted efficiently will increase stride length and minimize contact time, thus improving impulse patterns. Contact times that are excessively long are because movement periods below the ankle require clinical podiatry. Pressure profile analysis with sensor-rich insoles are appropriate to reveal the cause of excessive contact time.
Of course, even more interpretation can be done with the aforementioned measures and other metrics are worth exploring. The rationale for the selected indices and what to look for with interpretation is the ease of getting the information and the magnitude of the effect of improving the numbers. To me, it’s better to adapt the coaching models to improve the variables that matter, instead of forcing the athletes to do what I like doing.
It requires some homework and change that might not be comfortable, but removing the style from coaching and focusing on solid training is smart. Remember that a coach’s personality should be a focal point with athlete communication and relationships, but not of the way they train people. Coaching style isn’t just about training so, ironically, those that have a set style tend to not take advantage of their gifts.
High-Resolution Prescriptions in Acceleration
The final step is deciding on the best overall choice to make when coaching acceleration and then preparing general qualities of it. The most common mistake I see here is bias towards what coaches want to do and what athletes like to do, instead of doing what should be done based on past performances and training data. It’s fair to say that, if a program is constantly helping athletes get faster, do not reinvent the wheel—just keep reinforcing what works.If a program helps athletes get faster, don’t reinvent the wheel—just keep reinforcing what works. Click To Tweet
Technical Model – For years, I have seen athletes get faster using the same loads in training, regardless of the modality. Specific rehearsal is not to be underestimated, as it has worked for hundreds of years and is timeless. Knowing what to do with great preparation technique-wise is much more likely to get results than loading athletes or other general training factors. The higher the velocity, the less influence general training has, and the law of specificity matters at all levels of training.
Coaches must decide if the athlete needs to become a better sprinter if they lack fluid and coordinated movement. A simple way to discover if an athlete needs more specific skill work is to see if their times are less impressive than their outside training scores. Energy and time are finite, so when everything but the times improve it’s important to redistribute resources to direct sprinting.
Neurological Model – There’s a growing interest in the brain (neural pathways) and respective neurochemical and biomaterial (propulsive tissues) adaptations in sports performance. While related to teaching and the technical model, the neurological model is more about fatigue and the rate of adaptation over motor learning. Much of the research is on kinetics and kinematic factors over the more subtle variables that are less concrete and less accessible to measure.
For example, the Neuromuscular Junction is at the cellular level, and we don’t know much about how those changes occur via acceleration to specific muscle groups or if this is even worth exploring. Then we have the molecular level, and the way some athletes are genetically more likely to have poor collagen remodeling patterns and could be susceptible to Achilles tendon ruptures if their programs are overzealous in jump training. As Hakan Anderson has said many times, we are more likely to get a man on Mars than discover how man fatigues in the 100m dash, so a lot of the deeper biological models are still speculation.
Mechanical Model – The mechanical side of things is not biomechanical or even biochemical exactly, it is more specifically training areas that may not easily show up in research like ankle stiffness at specific joint angles, isokinetic strength of hip flexors, and even addressing foot strength. An easy way to relate this is to Formula One racing, where all the little things are being fine-tuned to get small but extremely valuable speed changes.
Unfortunately, coaches can jump to conclusions too early by going too specific when much of the optimization of an athlete will fall into place. Only when things lag or show up as restrictions to development should they be addressed. Otherwise, coaches can get lost with all of the available options to attack. When core competence in acceleration testing is done and a true opportunity is shown to exist, then coaches should invest into the small specific adjustments.
Acceleration work with the 1080 Sprint does differ from sleds in many ways, but all of the principles of training can be used. Many of the system features are not interchangeable back to sled work, though. Video feedback and other tools are all part of the equation, but you can get lost in analyzing one errant run versus a repeated pattern.
Unknown Sprint Parameters and Future Directions
By the time this article reaches its one-year mark, much of what is shared is going to be refined and improved upon. The goal now is merely a framework with enough examples so coaches can build their own acceleration training model beyond what percentage of load, speed, or force characteristics to use during resisted sprints.
Some of the great work by George Petrakos and colleagues is an excellent roadmap, and this article adds enough details to polish up already great training programs. I hope this set of ideas isn’t seen as the conclusion to better acceleration training, but a middle area to something even more useful.