Breaking down preconceived ideas
Maximum strength is the ability to produce a very intense effort for a short period of time. In weight training, this corresponds to sessions where you lift very heavy weights—generally more than 90% of your maximum—with few repetitions, often between 1 and 3. When people talk about weight training and endurance, many think of sessions with light weights and numerous repetitions. The idea behind this is to avoid "building too much muscle" so as not to add bulk to the body. The result? Maximum strength sessions—with very heavy weights, few repetitions, and plenty of rest—are often overlooked.
But is this really justified?
Recent research shows, on the contrary, that these sessions can improve several key factors of endurance performance, without harming our athletic profile.
Maximum strength and muscular power
First, a simple reminder: power is force multiplied by speed. So if you want to be more powerful, you can improve one or the other… or both. Maximum strength training sessions allow you to increase the “force” factor by strengthening your muscles, but especially by improving their neural coordination.
You become more capable of producing intense effort, without gaining much muscle mass — because these sessions aim for efficiency, not hypertrophy.
Maximum power for better running economy
This is where it gets interesting for endurance sports. Running economy is the amount of energy (and oxygen) our body uses to maintain a given pace. The better it is, the less energy we expend with each step.
Many studies have examined the impact of maximal strength training on performance factors in endurance sports (Berryman et al., 2018; Llanos-Lagos et al., 2024), and there is a consensus on the increase in running economy. The studies are clear: well-structured maximal strength cycles improve running economy. Why? Because we learn to better recruit our muscle fibers, stabilize our movement, and limit unnecessary contractions. These sessions will increase the recruitment of motor units (engaging a greater number of muscle fibers for the same movement), thus making us more efficient.
In other words, we become more “economical” in our effort.
The example of cross-country skiing.
A scientific review (Castañeda-Babarro et al., 2022) analyzed over 200 studies on strength training in cross-country skiers. The result? Maximal strength cycles (6 to 12 weeks) clearly improve work economy— without reducing aerobic capacity . Proof that it's possible to gain efficiency without sacrificing endurance.
How to incorporate maximum strength into your training.
Here are some simple guidelines for setting up an effective cycle:
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When? Off-season or at the beginning of general preparation, before specific training blocks.
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How long? A cycle of 6 to 8 weeks.
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How many times? 1 to 2 sessions per week.
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How? For example, 4 sets of 3 repetitions with a heavy weight (>85% of your maximum) with at least 3 minutes 30 seconds of rest , or even more if needed. The goal is to fully recover between sets to maintain a high level of strength.
This type of training requires technique and gradual progression. It's best to have supervision at the beginning to avoid injuries.
Conclusion
Heavy weight training isn't just for bodybuilders. When used correctly, it can be a valuable asset for endurance sports: increased strength, improved coordination, and less energy expenditure for the same effort. And all this without sacrificing its lightweight and efficient profile.
Sources:
PMID: A simple method for measuring power, force, velocity properties, and mechanical effectiveness in sprint running PMID: https://pubmed.ncbi.nlm.nih.gov/28459360/ (Strength Training for Middle- and Long-Distance Performance: A Meta-Analysis)
Written by Jules Tuccinardi holds a Master's degree in sports science and physical performance. He is a physical trainer and coach for endurance athletes (skiing, trail running).
