Build, Maintain, Repeat: Why Year-Round Strength Training Wins for Young Runners
November 3, 2026
By Coach Chris Lee
7 min to read
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The strongest young runners are not the ones who lift the hardest. They are the ones who never stop.
Every winter in Boulder, we watch young athletes get stronger. They squat better, land softer, and run with more pop. Then spring arrives, the racing starts, and the strength work disappears. By next winter, they are back where they started.
This article is for parents. It explains how we plan strength training across a full running year, why winter is the best time to build, and why keeping strength during the season matters as much as building it. Every key claim links to peer-reviewed research, listed at the end.
The old-school pattern: start over every year
Here is the cycle we see most often:
Winter: the athlete lifts and gets stronger.
Spring: racing starts. Strength work stops because "we don't want heavy legs."
Summer and fall: months of running with no strength work. The gains fade.
Next winter: back to square one.
The problem is not effort. It is the gap. Strength fades faster than most families expect. In one study, teen athletes who stopped lifting for just four weeks lost about 5% of their jump height and 5 to 7% of their strength, and took longer to steady themselves after landing (Tran et al., 2017). Their sport practice alone was not enough to hold on to what they had built.
When strength resets every year, the athlete never gets to build on last year. They just repeat it.
The better season: build, peak, maintain, taper
Here is how we plan a full year for a spring runner:
Build (winter): steady, planned increases in strength. This is where the real gains happen.
Peak (late winter): we work up to the heaviest loads of the year, right before outdoor season.
Step down (first 6 to 8 weeks outdoors): as running picks up, we bring the load down step by step.
Maintain (the rest of the season): not unloaded. We work only with loads we know their body handles well, so strength stays without hurting their running.
Taper (before big races): we cut back so they arrive fresh.
The two plans look the same until racing starts. After that, one athlete keeps most of their strength. The other loses it.
Why winter is the build window
Winter is when there are no races to protect. Running volume is lower, recovery is easier, and the body has room to adapt. That makes it the best time to push strength forward.
The research backs this up. In teen distance runners (about 17 years old), 10 weeks of twice-weekly strength, jump and sprint work improved running economy by about 3 to 4% and made them faster at top speed. It did this without adding unwanted body weight or hurting their aerobic fitness (Blagrove et al., 2018).
Running economy is how much energy it costs to hold a pace. Better economy means the same pace feels easier. That is a real advantage heading into spring.
Why keeping strength in season matters
The running season is hard on the body. High mileage breaks tissue down faster than it can rebuild. If strength work stops, the muscles, tendons and bones that protect the athlete get weaker right when the demand is highest. That is when injuries show up.
The good news: keeping strength takes far less work than building it.
• Young adults who cut their lifting to one-third, or even one-ninth, of their earlier amount kept the muscle they had built for 32 weeks (Bickel et al., 2011).
• A review of this research found strength can be held with as little as one session a week, as long as the weights stay challenging (Spiering et al., 2021).
• Endurance athletes who kept one strength session a week through 13 weeks of racing held their strength and kept getting faster (Rønnestad et al., 2010).
And that strength protects them. A review of 25 trials with more than 26,000 athletes found strength training cut sports injuries to less than one-third. Exercise programs as a group nearly halved overuse injuries, the kind runners get most (Lauersen et al., 2014).
Stretching, the warm-up many teams lean on, made almost no difference. Strength work did the most.
High mileage and growing bodies
The teen years are when kids build most of the bone they will carry for life. Lots of running, without enough strength work or enough food, can get in the way.
Here is what the research shows in young runners:
• Low bone density is common. In one study of high school runners, 14% of girls and 21% of boys had low bone mass for their age (Tenforde et al., 2015).
• Mileage is a risk factor. Teen boys who averaged more than 30 miles a week had about 6 times the odds of low bone density. Each added risk factor stacked on top of the last (Barrack et al., 2017).
• Years of running add up. In teen girls, running five or more seasons was one of the factors that predicted low bone density (Barrack et al., 2008).
• Hormones are part of the picture. When training burns more energy than the athlete eats, the body can turn down hormones like testosterone and estrogen, and bone health suffers. This is called Relative Energy Deficiency in Sport, or REDs (Mountjoy et al., 2023).
Strength training helps push the other way. Lifting and jumping put healthy stress on bones, and that stress helps kids and teens build more bone (Behringer et al., 2014). Among young adult male runners, those who lifted at least once a week had higher bone density than runners who did not (Duplanty et al., 2018).
Strength work is not a cure-all. Good fueling and smart mileage still matter. But it is one of the strongest tools we have to protect a young runner's bones.
Think of it like compound interest
Strength is a long-term investment. Each year builds on the base from the year before, as long as that base is kept.
This is the idea behind Long-Term Athletic Development (LTAD). Leading youth sports scientists and the NSCA, the main strength coaching group in the U.S., agree that young athletes do best with a structured plan that runs for years, not seasons.
Its goals are better performance, fewer injuries, and lifelong health (Lloyd et al., 2015; Lloyd et al., 2016).
