Strength Training for Endurance Sports: 

What Science Says.

 

by Simone Bisello

For years, endurance athletes have looked at the gym with suspicion. Even today, for many, it remains a debated topic: some consider it useless or even counterproductive, while others see it as indispensable. In the past, the idea was widespread that strength training could “bulk up” the athlete and therefore slow them down.
Today, scientific research states the opposite: incorporating strength training into an endurance athlete’s program allows you to:

• improve movement economy,
• increase power at key moments,
• reduce the risk of injury and ensure greater training continuity.

Why go to the gym if you practice endurance sports

Improving movement economy

Strength training allows athletes to consume less oxygen at the same speed and to move muscles in a more coordinated way, improving what is known as running economy. This helps runners and cyclists go longer with a lower perception of fatigue — a decisive advantage in endurance sports.
With the same VO₂max (maximum aerobic capacity), a stronger athlete can sustain the same intensity with lower energy expenditure. This is a key aspect when it comes to improving technical efficiency and overall performance in long-duration disciplines.
From a practical standpoint, strength training improves technical efficiency because it:

• reduces the energy cost of each movement;
• increases stiffness, that is, the ability of muscles and tendons to store and release energy more efficiently;
• optimizes intra- and intermuscular coordination, making movement smoother and less costly.

The result is clear: better movement economy, less fatigue, and a greater ability to maintain pace over time — fundamental elements for athletes involved in running, cycling, triathlon, and cross-country skiing.

More power at key moments

In endurance sports, resistance alone is not enough: the ability to change pace, accelerate uphill, and sprint at the finish is essential. Maximal and explosive strength training improves the ability to generate power, even after long periods of effort, when neuromuscular fatigue tends to reduce movement effectiveness. From a physiological perspective, this type of work increases RFD (Rate of Force Development), that is, the speed at which muscles produce force. RFD is one of the most important parameters in endurance disciplines, as it determines the ability to produce power peaks at decisive moments.

Training with maximal strength protocols and explosive exercises allows athletes to:

• increase the recruitment of fast-twitch muscle fibers;
• improve neuromuscular timing;
• maintain power output even under fatigue.

In practical terms: more watts on the bike, greater propulsion while running, and a better ability to respond when it matters — a crucial advantage for every endurance athlete.

Lower injury risk, greater training continuity

Strength training is one of the most effective tools for reducing injury risk in endurance sports. It improves joint stability, strengthens the muscles involved in running and pedaling mechanics, and helps distribute training loads more evenly across different muscle groups.
Runners, cyclists, and triathletes experience immediate benefits: fewer postural imbalances, fewer overuse injuries, and greater continuity in training — a fundamental factor for long-term performance improvement.
The goal of gym work is not “lifting weights” for aesthetic purposes, but rather developing a solid and functional structure capable of better absorbing stress, protecting tendons and joints, and preserving correct technique over time.

Maximal strength, power, and muscular endurance: what endurance athletes really need

To improve performance in endurance sports, it is essential to be able to produce force, transform it into power, and sustain it over time. These are the three capacities that allow athletes to run, ride, or swim more efficiently, especially during decisive phases of competition:

• Maximal strength: the foundation of all other expressions of strength. Higher maximal strength reduces the percentage of force required for each technical movement, meaning less energy consumption at the same pace and more stable technique over time.
• Power: force expressed at speed. It is decisive for pace changes, climbs, accelerations, and final sprints. Training power increases muscular reactivity and improves the ability to generate watts on the bike or propulsion while running.
• Muscular endurance: the ability to maintain output and technical control for the entire duration of the performance.

How and when to train them

1. A strength program for an endurance athlete should always begin with a phase of anatomical adaptation, lasting 3–4 weeks. This phase is essential to prepare muscles, tendons, and joints for training loads and to improve motor control. The goal at this stage is not to seek fatigue. Moderate loads are used, approximately 40–60% of 1RM (one-repetition maximum) — that is, 40–60% of the maximum load that can be lifted once. This allows athletes to learn movements correctly, improve stability, and build solid technique without excessive stress.During this phase, multi-joint exercises such as squats, lunges, deadlifts, and presses are the cornerstones of functional strength training — strength that can truly be transferred to the specific movement patterns of the sport..
2. After the adaptation phase comes the maximal strength phase, ideal during periods far from competitions (off-season). The same exercises are maintained, but with heavy loads (80–90% 1RM), low repetitions, and long recovery times.
3. The next phase, closer to the competitive season, involves power training, using moderate loads (30–60% 1RM) and explosive movements such as jump squats, sprints, or kettlebell swings.
4. Finally, muscular endurance is consolidated through circuits, time-under-tension work, and discipline-specific isometric exercises, which help maintain movement quality even under fatigue.

During the general preparation phase, two strength sessions per week are sufficient to build a solid foundation. During the competitive season, even one weekly heavy strength session, focused on multi-joint exercises, can be enough to maintain the benefits achieved and preserve neuromuscular quality.

Practical applications in endurance sports

Cycling

Strength is the foundation of power on the pedals and is crucial for improving watt output, accelerations, and stability.

• Explosive strength and coordination are essential for sprints.
• Over long distances, muscular endurance and core stability become central.
• In MTB and gravel disciplines, eccentric strength is also fundamental, helping absorb impacts and maintain bike control.

Across all disciplines — road, MTB, gravel, or time trial — the ability to generate power, manage fatigue, and maintain technical precision greatly benefits from strength training.

Running

• In short efforts such as 5K and 10K races, power and stiffness dominate, both essential for a reactive and economical stride.
• In the half marathon and marathon, muscular endurance and stability play a major role, while in trail and ultratrail running, eccentric strength and control are especially important to manage descents, technical terrain, and long elevation changes.

Strength training helps improve reactivity, reduce the decline in running economy, and maintain an effective pace for longer periods.

Triathlon

Strength is the factor that allows athletes to integrate three different movement patterns — swimming, cycling, and running — while maintaining efficiency throughout the race.

• In sprint and Olympic distances, power and rapid muscle recruitment are crucial to sustain high intensities.
• In long-distance triathlon, muscular endurance and core stability become priorities, essential for preserving technique and efficiency after many hours of effort.

Appropriate strength training enables triathletes to improve overall performance and reduce the injury risk associated with high training volumes.

Nutrition and supplementation to support strength training in endurance sports

To effectively support strength training in endurance sports — such as running, cycling, and triathlon — nutrition plays a key role, particularly protein intake.
Daily protein requirements for endurance athletes range between 1.4 and 1.6 g per kg of body weight. After a strength session, it is advisable to approach the upper limit (around 1.6 g/kg) during the following 24–48 hours to promote muscle repair and adaptation to training loads.
Protein quality is just as important as quantity. High biological value sources — eggs, meat, fish, dairy products, Greek yogurt, and whey protein — provide all essential amino acids needed for protein synthesis.

Athletes following a plant-based diet can achieve a complete amino acid profile by combining grains, legumes, soy, and quinoa. When it is not possible to properly distribute protein intake across meals (about 0.5 g/kg of body weight per meal), or in the case of vegetarian or vegan diets, supplementation with essential amino acids (EAAs) and plant-based proteins can be a useful solution to support recovery and adaptation processes.

Another key factor is protein timing: muscle sensitivity to amino acids remains elevated for up to 24–48 hours after a strength session. Consuming 20–40 g of protein within the first two hours after training helps optimize protein synthesis.

A whey protein shake is particularly effective due to its rapid absorption and its ability to support recovery, especially when running or cycling sessions are planned for the following day.

Strength training can reduce the rate of glycogen resynthesis. For this reason, post-workout nutrition should include fast-absorbing carbohydrates (such as maltodextrins) combined with a protein source. This supports both energy recovery and muscle fiber repair.

Athletes new to gym training may experience DOMS (Delayed Onset Muscle Soreness) within 24–48 hours after sessions. Daily supplementation with omega-3 fatty acids (at least 1.5 g of EPA + DHA) helps modulate inflammation and improve recovery.

Tart Cherry extract, thanks to its antioxidant properties, can reduce pain markers and improve muscle function when taken in the hours following more demanding sessions

Conclusions Training strength means improving efficiency, power, and the ability to resist fatigue. A strong muscle is not slower; it produces the same force with less energy, allowing athletes to run, ride, or swim longer and with higher quality. Hours in the gym are not necessary: two well-structured sessions per week are enough to build a solid foundation, reduce injury risk, and improve overall performance. The gym is not in contradiction with endurance: it complements and enhances it. Ultimately, strength is the foundation of endurance.

 

 

Bibliography 

• Aagaard, P., & Andersen, J. L. (2010). Effects of strength training on endurance capacity in top-level endurance athletes. Scandinavian Journal of Medicine & Science in Sports, 20(S2), 39–47.
  - Beattie, K., Carson, B., Lyons, M., & Kenny, I. C. (2014). The effect of strength training on performance in endurance athletes. Sports Medicine, 44(6), 845–865.
  - Blagrove, R. C., Howatson, G., & Hayes, P. R. (2018). Effects of strength training on physiological determinants of middle- and long-distance running performance: a systematic review. Sports Medicine, 48(5), 1117–1149.
  - Berryman, N., Mujika, I., Arvisais, D., & Millet, G. Y. (2018). Strength training for middle- and long-distance performance: a meta-analysis. International Journal of Sports Physiology and Performance, 13(1), 57–63.
  - Cormie, P., McGuigan, M. R., & Newton, R. U. (2011). Developing maximal neuromuscular power: Part 1 — Biological basis of maximal power production. Sports Medicine, 41(1), 17–38.
  - Louis, J., Hausswirth, C., Bieuzen, F., & Brisswalter, J. (2012). Strength training improves running economy in trail runners. International Journal of Sports Medicine, 33(10), 824–830.
  - Yamamoto, L. M., et al. (2008). Effects of resistance training on endurance running performance among highly trained runners: a systematic review. Journal of Strength and Conditioning Research, 22(6), 2036–2044.
  - Phillips, S. M., & Van Loon, L. J. (2011). Dietary protein for athletes: from requirements to optimum adaptation. Journal of Sports Sciences, 29(sup1), S29–S38.
  - Takeda, M., et al. (2017). Influence of tart cherry on recovery and performance: a systematic review. Journal of the International Society of Sports Nutrition, 14(1).
  - Maughan, R. J., & Shirreffs, S. (2012). Nutrition for sports performance: issues and opportunities. Nutrition Bulletin, 37, 347–355.

 

IMPORTANT NOTICE: the information provided is for informational purposes only and does not replace the advice of your physician or a qualified healthcare professional. The content is intended for healthy individuals: any dietary regimen or physical activity must be supervised by a qualified professional, as required by Italian law. Enervit S.p.A. assumes no responsibility, as the information is purely educational. Anyone wishing to begin a nutritional or physical activity program should first consult with their trusted specialist.