Strength Training for Endurance Athletes: Why it's Essential for Performance

Strength training is now recognised as a fundamental pillar of health, performance, and longevity. From everyday movers to elite triathletes, athletes across all sports benefit from more than just miles in the bank. Strength training isn’t about bulking up; it’s about building a body that is stronger, more efficient, more resilient, and better equipped to handle the demands of life and sport.

Key Benefits at a Glance

• Performance Enhancement: Stronger muscles improve power, efficiency, and endurance across any activity — whether it’s running faster, cycling longer, or swimming with better technique.
  
• Injury Prevention: Lifting strengthens muscles, tendons, ligaments, and bones, creating the protective foundation that reduces the risk of both overuse and acute injuries.
  
• Health & Longevity: Strength training boosts bone density, supports joint health, improves posture, and helps maintain muscle mass and metabolism as we age.
  

Common Misconceptions Among Endurance Athletes

Many endurance athletes hesitate to add gym work because of familiar concerns:

• “Strength training will make me sore.”
  
• “I’d get more benefit from another hour on the bike.”
  
• “I don’t want to bulk up.”
  

The truth? The benefits go far beyond the old stereotype of gym work being just for bodybuilders. In fact, there is a growing body of research — and plenty of real-world results — showing that strength training is a game-changer for middle- and long-distance endurance athletes.

During my Master’s, I worked alongside a PhD project that broke down some of the key benefits. Here are three of the most important ones:

Benefit 1: Go Faster With Less Energy

Strength training improves your muscles’ ability to absorb and redistribute energy while producing more force in less time. This means every stride, pedal stroke, or swim pull costs less energy.

Put simply: a stronger athlete is a faster athlete.

Benefit 2: Build Injury Resilience

One of the most powerful benefits of lifting is its effect on tissues that are often overloaded in endurance sports:

• Bone Health: Training at loads greater than ~80% of your 1 rep max has been shown to increase bone mineral density, reducing the risk of stress fractures.
  
• Tendons & Ligaments: These tissues respond positively to load, becoming thicker and more resilient. This helps raise your threshold against overuse injuries like Achilles tendinopathy or IT band pain.
  
• Muscle Strength: A stronger muscle can handle greater force before breaking down, making it more robust against both acute strains and repetitive stress.
  

By reinforcing the whole musculoskeletal system, strength training allows you to train consistently and sustainably — the number one factor in long-term endurance success. (Lauersen JB, Andersen TE, Andersen LB., 2018)

Benefit 3: Improved Running Economy

Running economy — how efficiently you convert energy into forward motion — is influenced by biomechanics and neuromuscular control. Strength training enhances both, helping athletes run with better form and less energy cost. Research suggests that incorporating strength work can improve running economy by up to 4% — a huge advantage over long distances.

(Blagrove, R.C., Howatson, G. & Hayes, P.R., 2018)

How to Add Strength Training Into Your Program

There are different types of strength training, each creating unique adaptations. While they can be blended, it’s often most effective to focus on specific blocks of training that complement your endurance season.

Heavy Resistance Training

• Goal: Build maximum force and joint resilience.
  
• Why: Higher force production improves speed and protects joints from the repetitive load of running.
  
• When: Best added during base-building phases to lay the foundation for higher-volume and higher-speed training.
  
• Example Session:
  
  • Back Squat + Romanian Deadlift + Rows + Overhead press
    
  • 3–5 sets of 3–5 reps
    
  • Weights at >80% of 1 rep max
    

Muscular Endurance Training

• Goal: Improve fatigue resistance at the muscular level.
  
• Why: High-rep training increases capillary density, boosting oxygen delivery and waste removal, which translates directly to better aerobic efficiency.
  
• When: Often added within the build phase, where athletes are holding lactate thresholds for longer.
  
• Example Session:

• 3–6 sets of 12–15 reps
• Cycling → squats, lunges, step-ups
• Running → calf endurance, single-leg stability
• Swimming → pull-ups, pull-downs, scapular stabilizers
  

Plyometric Training

• Goal: Improve the stretch-shortening cycle (SSC) to make running more elastic and efficient.
  
• Why: Running itself is a plyometric action. By training the tendon’s ability to store and return energy, plyometrics improve running economy and resilience.
  
• Guideline: 25–40 total reps per session, split into single vs. double leg and horizontal vs. vertical movements.
  
• Example Session:
  
  • Single Leg: hops, bounds, controlled landings
    
  • Double Leg: countermovement jumps, broad jumps, landings
    

Specific Strength Training – The Soleus

• The soleus is a slow-twitch, high-force muscle designed for endurance and shock absorption. It tolerates forces up to 8× bodyweight by working with the Achilles tendon to absorb impact, store elastic energy, and redistribute it efficiently for propulsion.
  
• Training the soleus heavy can significantly improve running performance and durability.
  
• Example Session:
  
  • Heavy seated calf raises
    
  • 3–5 sets of 5 reps
    

How Much Strength Training?

• 2 sessions per week is ideal for most endurance athletes to see performance benefits without interfering with swim–bike–run training.
  
• Think in terms of two full-body sessions:
  
  • One unilateral focus (single-leg work, stability, asymmetry correction)
    
  • One bilateral focus (squats, deadlifts, Olympic lifts if appropriate)
    
• As always, volume and intensity should be individualised and adjusted depending on your triathlon program — so work with your coach to integrate it properly.
  

Final Takeaway

Strength training isn’t just a side dish — it’s a performance multiplier. From improving running economy to reducing injury risk and giving you the power to surge when it matters most, it’s one of the most effective tools an endurance athlete can add to their arsenal.

Train strong, race stronger.

Coach Sam

References 

Lauersen JB, Andersen TE, Andersen LB

Strength training as superior, dose-dependent and safe prevention of acute and overuse sports injuries: a systematic review, qualitative analysis and meta-analysis

British Journal of Sports Medicine 2018;52:1557-1563.
Blagrove, R.C., Howatson, G. & Hayes, P.R. Effects of Strength Training on the Physiological Determinants of Middle- and Long-Distance Running Performance: A Systematic Review. Sports Med48, 1117–1149 (2018). https://doi.org/10.1007/s40279-017-0835-7