Boulder is full of endurance athletes — runners, cyclists, triathletes, trail athletes — and a lot of them treat strength training as optional, or skip it because they think it will make them heavy and slow. The research and the practice both say otherwise. Here's the case for putting strength work in your program.
The Economy Argument
The strongest reason an endurance athlete should lift is economy — how much energy it costs you to hold a given pace. Strength training improves running and cycling economy, which means at the same effort you go faster, or at the same speed you spend less.
The mechanism is straightforward: stronger muscles and stiffer tendons return energy more efficiently with every stride or pedal stroke. You're not building strength to use it directly in your sport — you're building it so the work you already do costs less.
Durability and Injury Prevention
The second reason is durability. Endurance sport is high-volume, repetitive loading, and that's exactly the profile that produces overuse injuries — runner's knee, IT band issues, stress reactions, Achilles trouble.
Strength training builds tissue that tolerates that repetitive load. Stronger muscles, tendons, and bones handle the accumulated stress of high mileage better. For most endurance athletes, the season-ending problem isn't fitness — it's an injury that interrupts training. Strength work is one of the most reliable ways to keep that from happening.
The Bulk Myth
The fear that lifting will add slowing weight is the most common reason endurance athletes avoid the gym, and it's misplaced. Building significant muscle mass requires a specific combination of training volume and a calorie surplus that endurance athletes — training many hours a week — almost never hit by accident.
Strength training for an endurance athlete is programmed for exactly the opposite: lower-rep, higher-load work that builds strength and tissue quality without much size. You get stronger and more durable while staying essentially the same weight.
Periodizing Strength Around Your Season
Strength work for an endurance athlete has to fit around the sport, not compete with it. That means periodizing it across your race calendar.
In the off-season and base phase, you can do the most strength work — building a foundation while your sport-specific volume is lower. As the build phase ramps up and races approach, strength work shifts to maintenance: less volume, just enough to hold what you built. In the final taper, it backs off further. Done right, the gym work complements your run, ride, and swim volume instead of interfering with it.
Endurance Strength Training in Boulder
GYM N°5 in Gunbarrel coaches strength for endurance athletes — runners, triathletes, cyclists, and trail athletes. Programming is built around your race calendar and key sessions, so the work in the gym makes the work in your sport better. Membership is application-only and capped, with 24/7 access, so you can fit lifting around long runs and ride schedules.
Coaching is available in-person in Gunbarrel, Boulder, or online through the Team Thick Training app. If you've been meaning to add strength work but weren't sure how to fit it in without wrecking your training — that's exactly the problem the coaching is built to solve.
Train at GYM N°5
Private strength training in Gunbarrel, Boulder. Powerlifting, Olympic weightlifting, strongman, physique, and athletic performance. 24/7 member access.