Want to Get Faster? Improve Ground Contact Times with Tom Comyns

The Big Takeaways

• To improve ground contact times (GCTs) where it matters (on the athlete’s field of play) you have to get them to feel what it’s like to produce force in a minimal amount of time
• Measuring GCT with Output gives you objective data that positively impacts your programming and coaching 

About Prof. Tom Comyns 

Tom is an educator and coach whose research and teaching interests encompass all aspects of Human Movement Science, particularly emphasizing Strength and Conditioning (S&C). Tom holds a BA in Physical Education (1996), an MSc in Motor Skill Acquisition (1999), and a PhD in Strength Training for Rugby Union (2006). His PhD research, funded by the IRFU, provided scientific evidence for optimizing the potentiation benefits of complex training for rugby players. 

Following his PhD, Tom worked as an S&C coach with Munster Rugby and the IRFU. He later became the Head of S&C at Sport Ireland Institute, where he led S&C provision and strategy for Ireland's Olympians and Paralympians. Currently, Tom is a Professor of Strength and Conditioning in the PESS Department at the University of Limerick and coaches several of Ireland's Olympic and Paralympic track athletes.

In addition to his academic and coaching achievements, Tom is an Olympian and an accomplished Irish sprinter, having competed in the 4 x 100 m relay for Ireland at the Sydney Olympic Games.

The Relationship Between GCT and Speed

There are seemingly a million methods available to practitioners to get their athletes faster. Nothing beats sprinting with maximum intent over distances commonly seen within the athlete's sport. Specificity will always reign supreme. But baked into this specificity is a modifiable physical quality that, when tapped into, can positively impact sprint times across various sports. This is an athlete's ground contact time (GCT).

Ground contact time, as the name implies, is simply the amount of time that an athlete spends on the ground. If we can train an athlete to produce the same amount of force in less time, we have a faster athlete. Keeping specificity in mind, we don’t just want the shortest GCT possible; we want it to be within a bandwidth specific to the demands of their sport and position. Getting an NFL running back faster may look slightly different than getting a 100m sprinter faster. When looking at the short sprints in track, Tom saw that the highest-level athletes only spend 0.1-0.12 seconds on the ground (some even shorter than this) while still producing forces that can rise above 8 times body weight. This meant that the commonly used fast stretch-shortening cycle cut-off of 0.25 seconds was way too slow for the demands of the sport and a primary goal of training would be to improve an athlete's ability to tolerate shorter GCTs without experiencing breakdowns in other elements of their sprint technique. 

This concept has led Coach Tom Comyns to build out a plyometric progression that helps athletes understand what it feels like to truly have short contact times and then progress their ability to produce high levels of force within that specific time window.

How to Improve GCT 

Below is the progression that Tom works through with athletes of all levels. It is informed by data but still driven by his ability to effectively cue his athletes intentionally.

Extensive Pogo’s

To start, Coach Comyns will have athletes perform higher volumes of low-intensity pogo hops. The point of this exercise is to get the athletes to “feel” what it’s like to actually have short ground contact times. Even for his elite-level athletes, “sometimes it takes some regression for athletes to know what it means to get off the ground quick,” says Tom. 

Because this first step is more about motor learning than anything else, he makes a point to always ask the athletes how it felt before giving them any objective feedback on the outcome of the movement (GCTs). 

“They need to know what it feels like [to maintain fast GCTs] if they want to do it where it matters, on the track”

Hurdle Jumps

After athletes have shown that they’re proficient with low hurdles, both quantitatively and qualitatively, Tom progressively intensifies the movement by raising the hurdle height over time. Importantly, at this phase, the goal is still working within the GCT range specific to track sprinting. To accomplish this, he uses the height of the hurdle as a constraint that will modify the athlete's outputs. A low hurdle is easy for the athlete to get over but challenges them to produce a little bit more force than the pogo jumps, while a higher, hip-height hurdle forces the athlete to produce more force to complete the task. Again, athletes only move to higher heights during this stage of the progression if they can maintain their GCTs.

Education remains an important factor throughout this stage.

‍“We want them to feel like they’re effortlessly rebounding off the ground. When the fastest athletes in the world sprint, they feel like they’re just passengers on a speeding train,” says Tom.

This motor learning focus continues to increase the likelihood of transfer when applying it back to sprinting.

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Drop Jumps & Intensive Pogos

The final stage of the progression involves any form of maximal intent plyometric movements with short GCT. This includes drop jumps, hurdle jumps, intensive pogos, bounding, and single-leg jumping. During this stage, Tom will begin to view RSI, the relationship between jump height and ground contact time. While the goal of the exercise has slightly shifted in favor of intensity, it is still important that the athlete does not sacrifice ground contact time.

“When looking at RSI, you have to go deeper into which side of the equation is driving the ratio. Whether they need more force or faster GCT, I can base my coaching cues on their performance.”

One of the most impressive aspects of Tom’s process is how he connects data to individualized coaching. Too often, coaches either do not utilize the data they collect or just blindly give it out to their athletes. Using it to further individualize communication goes a long way in making changes stick for the athlete.

“Output allows me to be a better coach.”

How Tom Leverages Output

Tom uses output in many ways that we’ll dive deeper into here:

• Objectively tracking training 
• Motivating, engaging, and reassuring his athletes 
• Monitoring performance when athletes are on the road

Objectively Tracking Training

As you now know, testing and training GCT is extremely important if your goal is to get your athletes faster… but doing this in a practical setting can be a challenge. Force plates are impractical to move around, laser systems cannot be used with objects like hurdles and boxes, and jump mats can be unreliable. Output has given Tom a system that allows him to reliably and objectively track GCT in any environment his athletes train. This allows him to make coaching and programming decisions based on his athlete's performance in movements specific to the athlete's sport. 

"Being able to track and manage ground contact data with Output over time is incredible."

Beyond measuring GCTs, Tom uses Output to track countermovement jump heights and to track barbell velocities in the weight room. 

Motivating, Engaging, and Reassuring Athletes

Consistent quality data has had a very positive impact on Tom’s athletes. His more elite sprinters, they love knowing how they are performing and getting the reassurance that the training they’re doing is moving the needle in the right direction. While his youth athletes like competing for the best score in a given movement. They also just enjoy navigating the app and, inputting data, and seeing their results over time. 

Tracking Performance on the Road

Tom has a unique setup with some of his athletes where they may be gone training in different camps for weeks at a time leading up to important events. For situations like this, he will give his athletes an Output device to travel and train with. “The portability makes it easier than what we’ve had to do for previous events,” says Tom. 

Output is easily portable, intuitive to use for athletes, and allows coaches to see data in real-time as it comes in. This empowers both the coach and the athlete to make informed decisions about their daily training plan.

“As you get close to a big event you really want to make sure you’re making the right decision. Output lets me make coaching decisions in real-time, even if I’m not with my athlete in person.”

Wrap Up

• Specificity in Training: Improving ground contact times (GCT) within the context of the athlete's sport and position is critical for enhancing speed.

• Plyometric Progressions: A structured plyometric progression, starting with extensive pogo hops and advancing to intensive movements like drop jumps and hurdle jumps, trains athletes to produce high forces in shorter GCTs.

• Motor Learning Focus: Emphasizing the feel of short GCTs helps athletes understand the mechanics needed for faster sprinting.

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