Hey Reader!

Having what I would call a medium-term injury is interesting. Initially, my mind and body were in full agreement that I had to rest, so stopping was easy to do and accept; the pain was pretty bad.

I'm six weeks into no running and have spent the best part of the last four on crutches, which, thankfully, seems to be working, as my leg is feeling a lot better. However, the muscles in my quad are acting very weird as they wilt away.

Interestingly, my mind is struggling to understand how I can still be, at best guess, six weeks away from returning to running. My mind wants me to start moving, believing the body is ready, and it's causing me to reflect on how easy it would be to unintentionally delay the recovery process by simply not acknowledging that I’m still injured.

Some of you reading this may not understand, but for those who have been sidelined during your running journey, even a brief injury that has kept you from running for a few days—when you feel the urge to return a day or two sooner than recommended—you'll likely grasp what I'm saying.

All this to say, don't rush coming back, even if your mind thinks you're ready or your body has stopped hurting. It's hard to know what is being sensible and what is overly cautious, but an extra day or two, or in my case perhaps a week, isn't going to hurt.

Now, let's continue with our strength training guide for running by examining reactive strength and plyometrics, particularly how they relate to running efficiency and trail technique.

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Reactivity For Running

Whether you are training for the track, roads, or trails, becoming more "springy" matters.

When I say springy, I mean your running style becomes more reactive. The force developed through heavy resistance training is transferred into the ground more rapidly, with less energy wasted due to vertical oscillation (which we spoke about last week).

If you watch an elite, especially in the distance events on the track or on the roads, look at how they run and, for the best of them, it looks like they float with almost no movement aside from the legs elegantly cycling through and their feet gently tapping the ground. Yet, somehow, they are able to do this at incredibly fast paces?!

Well, this is due to their reactive strength.

Reactive Strength

"Reactive strength represents a runner's capacity to efficiently use the SSC (Stretch-Shortening Cycle) and elastic energy produced by the muscle-tendon complex." - Fei, 2021​

Reactive strength enhances running economy, allowing you to maintain a given pace while using less energy. It works by optimising the Stretch-Shortening Cycle (SSC) of the lower leg, increasing leg stiffness and improving the storage and return of mechanical energy. In short: better stiffness equals better efficiency.

When running speeds increase, elastic mechanisms become even more important, playing a crucial role in performance. This is where plyometric training comes in. It is known for enhancing reactive strength and helps make each stride smoother and more powerful.

Ground Contact Time (GCT)

Ground contact time (GCT) is a key factor in running economy (RE). Research shows that shorter GCT can enhance performance by allowing a quicker transition from braking to propulsion, reducing speed loss, and minimising energy waste.

Interestingly, shorter GCT is also linked to greater leg stiffness, which further improves running efficiency. Elite endurance runners typically have a GCT between 0.13 and 0.17 seconds, whereas maximal force production usually occurs around 0.4 seconds—proving that speed and efficiency aren’t just about producing force but applying it quickly.

Why not spend more time on the ground to generate more force? Because prolonged ground contact increases braking forces, slowing you down and raising the risk of injury. A shorter contact time minimises braking and helps maintain forward momentum, making power development critical for efficiency.

Plyometrics: The Key to Reactivity

"Plyometric training (PL, i.e., jump-based training with light or no loads)methods target a specific outcome, such as the stretch-shortening cycle and muscle-tendon stiffness." - Llanos-Lagos, 2024.

lyometric exercises are one of the best ways to build reactive strength. They focus on the quick stretch-shortening cycle (SSC), which is crucial for energy return. The goal? Short ground contact times (under 250ms).

Some great plyometric drills include:

• Pogo Hops
• Skips
• Hurdle Hops
• Drop Jumps

What’s great about plyometrics is that they train the muscles to achieve higher levels of stiffness, making them more efficient. Research has shown how effective these exercises can be for increasing reactive strength.

By increasing musculotendinous stiffness, these exercises make your muscles more efficient. Research shows that adding plyometric training significantly improves reactive strength, making runners more economical and resilient.

Introducing Plyometrics into Training

There's mixed advice on whether to develop a certain level of strength foundation before implementing plyometrics, with evidence saying both yes and no. Anecdotally, I find that focussing on building a foundation of strength before implementing plyometrics tends to lower the injury risk at the muscle-tendon junction that we are working on.

Yes, running is a repetitive plyometric exercise, essentially, but when done in a different movement pattern than when not running, increasing muscle capacity is beneficial. That said, hill strides can be great to incorporate early on in your journey once a base easy running level has been achieved.

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How To Do Power Hill Strides - David Roche

Once you have built a good strength foundation, which may only take 4-8 weeks, depending on your starting point, I start to layer in plyometrics (alongside or following force absorption exercises like tall-to-shorts and depth drop).

1. During the Warmup

The first place to start incorporating low-intensity and low-complexity plyos is at the end of your warmup for the strength session.

Following mobility and activation, plyometrics can be a great way to prime the body for lifting and start to improve the neuromuscular potential for strength.

Begin with two feet, Pogo, and gradually work your way up to 20 to 50 repetitions over the course of a month or two. If you're a trail runner, try incorporating direction changes like moving forward, backward, and side-to-side, once you can maintain stiffness for those 50 reps. After that, you can progress into a single-leg variation of these movements.

2. Sequential Training

Once you have built this foundation, you can layer in the Plyometrics after you have completed a key strength block.

For example:

• Block 1: 4 x 5 Back Squat @ 85-90% 3RM
• Block 2: 3 x 5 Drop Jumps

Strength work first primes the nervous system, leading to better motor unit recruitment when performing plyometrics. This results in more efficient force application, reducing energy leaks during movement.

3. Complex Training

Complex Training (CT) alternates one heavy-strength exercise with one biomechanically similar plyometric exercise within the same block, leveraging the Post-Activation Potentiation for increased power output.

Example Block, 3 sets:

1. Strength: Back Squat - 3reps @ 90-95% 3RM)
2. Rest: 2-4 minutes
3. Plyometric: Drop Jump - 5 reps
4. Rest: 2-3 minutes

What is Complex Training (CT)?

If you have a good level of strength training knowledge already, you may have heard of Contrast Training (CCT) and be questioning if they are the same thing. I totally did, too.

The difference here is CCT uses a heavy strength exercise, followed by a lighter, explosive version of the same movement in a repeated fashion, whereas CT is a plyometric exercise.

For example, contrast training would look like:

• Strength: Trap Bar Deadlift (3x3 @ 90% 1RM)
• Explosive Lift: Kettlebell Swings (3x8)

A KB swing is not a plyometric but an explosive movement.

Complex training is best for:

• Improving power and running economy in endurance athletes
• Time-efficient strength + plyometric programming.
• Developing reactive strength and stiffness for runners.

Contrast Training is best for:

• Athletes who need more power endurance (e.g., sprinters, field sport athletes).
• Maximising strength & power transfer for runners needing explosive ability.
• Improving the ability to generate force quickly.

What is Post-Activation Potentiation (PAP)?

PAP is a neuromuscular phenomenon where a high-intensity strength movement temporarily enhances subsequent explosive performance. This occurs due to increased motor unit recruitment, improved neural drive, and greater muscle contractility after lifting a heavy load.

Essentially, the muscles "wake up" after a heavy strength exercise, making the following plyometric or explosive movement more powerful.

For optimal results, you need 2-4 minutes between the two movements and similar rest after the plyometric movement. This is done as, if performed too closely, fatigue from strength dominates, and PAP is not yet effective.

Benefits of PAP training:

1. Increases Reactive Strength Index (RSI) → Improves stiffness & energy return in tendons, crucial for running economy (RE).
2. Improves Late-Race Performance → Helps maintain power efficiency under fatigue, beneficial for kicks & surges in racing.
3. Reduces Ground Contact Time (GCT) → A shorter GCT means faster turnover and improved efficiency.

Practical Recommendations for Runners

New or Injury-Prone Runners:

• Start with low-intensity plyometrics as the final stage of the warmup.
• Then progress to Sequential Training (Strength first, then Plyos).
• Focus on gradual progression of plyometric intensity.

Intermediate & Advanced Runners:

• Use Sequential Training in Strength Phases (e.g., off-season).
• Use Complex Training in Performance Phases (e.g., race prep).
• CT is particularly useful when trying to translate strength gains into running speed & efficiency.
• Start to add load to the plyometrics as long as your GCT is fast.

Past Newsletter Editions

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Closing Thoughts

This was a big one today with a lot of new terms. Start simple and build complexity and intensity, and you will be able to help propel your running economy forward, leaps and bounds, you might say.

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