Jonas Tawiah-Dodoo is the head coach and founder of Speedworks. He was a part of the UK Athletics Apprentice Coach program in the four-year lead-up to the London 2012 Olympics, working with world-renowned coaches Dan Pfaff and Stuart McMillan. His experience in sport is not limited to athletics, as he has worked with rugby for several years.
Since graduating from the Apprentice Coach program, Jonas has worked closely with a number of talented young sprinters. His most recent prodigy is Reece Prescod, the 2018 European Champion 100m sprinter.
Freelap USA: What are the key attractions of acceleration and maximal velocity, and how do you develop them in training?
Jonas Dodoo: When I look at sprinting, acceleration, transition, max velocity, and even change of direction, before I start to really talk about the full motion and the whole run, I probably just look at one step. So when we talk about attractors, or KPIs, or anything, I always revert back to underlying physical and mechanical properties.
I am essentially a simpleton and like to focus on just a few key things in running and explosive movement. I’m thinking about projection and what the hips are doing. I’m thinking about reactivity, what the feet and knees are doing. I’m thinking about switching, and limb exchange; Frans Bosch talks a lot about the extensor reflex. I’m thinking about stability and dissociation around the lumbo-pelvic area and how this supports flexion/extension in a symbiotic way.Before I talk about full motion and the whole run, I look at just one step, says @EatSleepTrain_. Click To Tweet
Before looking deeply at the kinetics and kinematics of the sprint, I take a more simplistic view of movement and then use this to help filter my judgement at more complex levels of analysis. Over the past 10 years, I have learned that being able to summarize my analysis, coaching cues, and interventions to these key areas has made me a better consumer of biomechanics, sports medicine, and S&C.
Freelap USA: What’s your take on resisted sprinting—how heavy do you go or how much velocity decrement would you allow for and in what training phases would you use that?
Jonas Dodoo: Heavy resisted sprinting creates an effective environment for teaching acceleration, as well as training the underpinning properties in tandem. The performer needs to produce large horizontally oriented forces from their hips if they intend to accelerate forward. If they don’t orient large forces forward, then they quite frankly won’t go anywhere. The performer needs a solid base of support so intuitively creates stiff ankles. If they plan on doing this continuously over a number of steps, then they have to switch their limbs effectively.
The good thing about very heavy resisted sprints is that they slow down the movement. This can be valuable from a skills acquisition perspective for the athlete and for the development of the real-time coaching eye of the coach.
I have used resisted running at varying resistance depending on my goals and the time of year. In my experience, very heavy resisted sprinting (>75% body mass) transfers well to early acceleration. This is a section of a run where an athlete can develop more than 50% of their top speed in less than one second so it has very high importance in setting up the race. This is clearly a priority and so when we are running 20m with a very heavy sled, I tell the athletes we are really just practicing our first three to four piston steps again and again and again.
A medium weighted sled (around 50% body mass) is more about late acceleration where ground to air ratios decrease and ground contact times decrease, as we are adding more and more vertical forces and raising the center of mass. This is a section of the run where athletes can often get stuck “over pushing,” which can destroy a smooth transition into top speed mechanics. Therefore, the resistance needs to be high enough to create a bit of a challenge but not so high that the only way to succeed is with full triple joint extension.
A light resistance is a great way to maintain a continued horizontally oriented force during upright mechanics. This may not be a stimulus reserved for your vertically gifted sprinters who may just go up and down—creating pretty shapes like Asafa Powell— but don’t project themselves towards the finish line any faster. After all, acceleration doesn’t end when you have vertical posture, it continues if you can increase your stride length (projection) while spending less and less time on the ground (reactivity) and/or switching your legs faster (limb exchange). At the end of acceleration, individuals are rewarded if they have the highest top speed (= stride length x stride frequency).
Ryu Nagahara and his research group have done some excellent phase analysis of sprinting and I recommend that readers take a deep dive into their work.
Freelap USA: You’ve mentioned whittling individual differences down to speed- or force-dominant, and that you’ve gotten away from pushers and pullers a little bit. Can you explain how you arrived at that and how it filters into the way you train athletes?
Jonas Dodoo: Acceleration is an exponential activity. We want to steepen the front of the curve and also extend the peak of the curve. JB Morin has popularized a way of analyzing athlete sprint times and weighting their strengths versus their weaknesses relative to their theoretical potential. This is an awesome place to start. It removes your coaching bias and allows the data to tell a story.
For me, this is surface level analysis but provides context for how I then analyze kinematics and the relationship between velocity, step length, and ground contact time across the entire sprint. These variables also have an exponential curve and their relationship will dictate stride frequency.
The question I ask myself is at what step or phase does the athlete lose harmony and what variable was the rate limiter.
So, a force-dominant sprinter may be excellent at projection out of the blocks but may not set up reactive contacts at some point in their acceleration. This may be due to a lack of rise in center of mass, which is likely on purpose in order for them to project themselves MAXIMALLY forwards. I would always suggest finding an OPTIMAL and harmonious relationship between stride length and frequency. Maximal projection always has a knock-on effect to late acceleration and all the way into their max velocity posture and rhythm.
Your velocity-dominant sprinter may have poor horizontal projection ability, they may position their forces too vertically, or they may not have much extension force whatsoever. The use of frequency may be a more dominant strategy and stride lengths may only start to grow harmoniously once the sprinter is exiting their late acceleration. This individual may be last to the 30m mark, but has set up the frequency and ground contact times that allow for a faster finish. Fast finishes look dramatic and are good for spectators, but a 9.8 guy can’t run down another 9.8 guy. So, either way you need to be in the race from the beginning if you’re aiming to win a major championship.You need to be in the race from the beginning if you want to win a major championship, says @EatSleepTrain_. Click To Tweet
Dan Pfaff has always preached the need for harmonious relationships in the kinematics of sprinting. So, I would rather start with the data to describe the current strategy and then use my intuition to help guide athletes towards potential solutions. As soon as I box the athlete into a puller or pusher, I am making some assumptions that ultimately limits their number of potential solutions. Instead, I am better off thoroughly identifying the constraints of the task and then creating an environment for the athlete to solve the puzzle. This often ends with some pushers learning how to pull and vice versa. We should be able to do both!
Freelap USA: What is your approach to contrast training and the utilization of potentiation-based training means with athletes, and does it vary at all between different types of athletes?
Jonas Dodoo: I think the whole year is a contrast. I think cycle to cycle you are applying contrast, and so, yes, at the end of the year, you may be more concerned about how your French Contrast is building into a power/speed session or block session. That might be the endpoint I’m thinking about, but I’m probably also thinking about how I’m using my loading strategy in week 1 to similarly contrast what I’m doing in week 2 and building up to a taper.
Similarly, I’m thinking about how I’m using an activation day and my exercise choice to support the work happening the next day or how I am using plyometrics and low-volume sprinting in a warm-up to support effective running mechanics in my endurance sessions. I like to group contrast/complex training and PAP under one umbrella as they are simply a means of intensification of training and to provide a novel stimulus to the nervous system. So, my contrasts year to year have a similar kind of theme, but probably evolve as the athlete becomes accustomed to it.
Which athletes does it work for? You experiment to see who it works for, really. For guys who have really good work capacity, you can usually use exercises that are more intense and more stressful for that athlete because they have a relatively good capacity. For others, it might make them too uncomfortable and distract them from the intensities needed for the latter exercise. That is when I might just use really light bodyweight forms of plyometrics and special strength drills to contrast with sprinting, as opposed to using a low box step-up and some bounding prior to blocks. This might be my two different ends of the spectrum of contrast training for my athletes.
Freelap USA: What are some common lynchpin points to fix in sprinting?
Jonas Dodoo: Switching, also known as limb exchange. Efficient limb exchange is often counterintuitive in comparison to projection. We ask for large forces into the ground with some adequate hip extension, but we also ask for short ground contacts and front-side mechanics, which is essentially suggesting we decelerate the limb early during the ground contact. When on the ground push yourself forward, but not so much that you over-rotate. Also be quick, but not so quick that you under-rotate.
That’s where people get stuck—they know that they need to project themselves, but they also need to prepare for the next step. They know they need to move their legs fast, but they also need to push with optimal extension and separate their knees.Efficient limb exchange is often counterintuitive in comparison to projection, says @EatSleepTrain_. Click To Tweet
The great thing about an effective switch is the pretension it creates in the whip from the hip. This enables the sprinter to spike their ground reaction force, which creates the required forces in a short amount of time. This then enables the stance leg to decelerate and start its next cycle as a swing leg. I think this is the rate limiter for many sprinters and athletes returning from injury. I think that’s why Frans Bosch is so hot on that as an important KPI and so am I. It’s no surprise Ralph Mann’s technical model is so Asafa Powell-esque because on paper, and in reality, that is a really efficient way to project yourself down the track.
As I mentioned earlier, I believe the underpinning quality to switching is lumbo-pelvic dissociation. I have seen athletes training their core and developing torso rigidity when it actually needs to be fluid and able to rotate, extend, and abduct, one ilium the complete opposite of the other. When you get down to that level, some people just haven’t had enough time developing that coordination ability. They may have spent time developing the tissue’s tolerance to fatigue or strain, but not at the appropriate lengths/torques, or with the appropriate co-contractions and timings.
I think limb exchange/extensor reflex is the bigger limiting factor out of the three key things I look at: projection, reactivity, and switching. The limb exchange normally brings it all together, and limitations in projection or reactivity are normally what takes away from your ability to switch really well. Switching almost opens the door to me understanding what is your strength, what is your weakness, and how we create a balance.
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