Maximal Strength

Definition:
Maximal strength is the highest amount of force a muscle can produce, independent of how quickly that force is generated.

Physiology:
This quality relies primarily on Type IIa muscle fibers, which can output high levels of force relatively quickly.

Training Guidelines:

• Load: >80% of 1RM

• Reps per set: <5

• Total session volume: <20 total reps to maintain quality and minimize fatigue

• Goal: Improve neural drive, motor unit recruitment, and absolute force production
  
  

As the load approaches your true one-rep max, reps per set should decrease.

Strength Endurance
Definition:
Strength endurance is the ability to maintain force production over extended periods which is essential for long-distance runners.

Physiology:
This quality relies on Type I muscle fibers, which are slow to fatigue and built for sustained work.

Training Guidelines:

• Load: <50% of 1RM

• Reps: Open-ended; the goal is high session volume

• Goal: Improve fatigue resistance and tissue capacity
  
  

Higher total volume, not intensity, drives adaptations here.

Reactive Strength

Definition:
Reactive strength is your ability to absorb and redirect force rapidly which is critical for efficient running mechanics.

Physiology:
This relies on Type IIx muscle fibers, the fastest and most explosive fibers in the body.

Training Guidelines:

• Priority: Speed of movement, not load

• Example: Plyometrics → focus on short ground-contact times

• Loading: Only increase weight after an athlete demonstrates proficiency with body weight

• For traditional lifts (e.g., squat):

  • Load: 60–80% of 1RM

  • Reps: <5 per set

  • Intent: Move the weight as fast as possible with excellent form
    
    

This trains the nervous system to produce force quickly—something runners benefit from during strides, surges, and hill running.

The Problem With Generic Programs (Like 5×5 for Runners)

You may come across claims such as “5×5 is the best strength workout for runners,” often paired with broad recommendations like using 50–85% of your 1RM. *This exact advice appeared in a major running magazine*

The issue? Sets and reps mean nothing without the context of load.

Let’s look at the extremes of the recommended range:

• At 85% of 1RM:
  Most people can only perform 5–6 reps, making a set of 5 extremely taxing. Performing that for 5 sets. Especially for endurance athletes who are already carrying high levels of chronic fatigue. Is impractical and counterproductive. The interference effect is real.

• At 50% of 1RM:
  Many could perform 20–30 reps, meaning a set of 5 is not even close to stimulating strength or strength-endurance adaptations. It’s simply not enough load or volume to drive meaningful progress. At best, 5×5 at 50% serves as safe, low-load practice for beginners learning a new movement.
  
  

This is why percentage prescriptions must match the intended adaptation.

How Endurance Athletes Should Structure Sets and Reps

Strength training is supplementary to running, not a replacement for mileage. Proper strength work helps runners tolerate more training, reduce injury risk, and produce force efficiently. But most endurance athletes don’t enter the weight room fully fresh, so expectations should match their training reality.

Here’s how to align strength training with the demands of an endurance season:

Early Training Phase

• Focus: Technique, tissue capacity

• Loads: Low to moderate

• Sets/Reps: Higher volumes (e.g., 2–4 sets of 8–12+)

• Goal: Build durability and movement proficiency
  
  

Mid-Season / Increasing Running Volume

• Focus: Building strength

• Loads: 70–90% of 1RM

• Sets/Reps: Lower reps per set (3–6), with 2–3 reps in reserve (RIR)

• Goal: Increase force production without compromising run training
  
  

Race Preparation Phase

• Focus: Power and speed

• Loads: 60–80% of 1RM

• Sets/Reps: Similar volumes but performed with maximal bar speed

• Goal: Maintain strength while sharpening neuromuscular qualities for racing