Most runners understand that strength training can be helpful, but many aren’t sure exactly why it matters, or how to do it in a way that supports their running goals. With limited time to train, it’s not always clear how lifting weights fits into a plan built around mileage, workouts, and recovery.

What Does Strength Training Do?

It's important to note that strength training isn’t about building muscle for its own sake. For runners, it’s about preparing the body to train more effectively, stay healthy, and run faster on race day. Resistance training supports faster running in several different ways:

1. Increases bone density: Resistance training stimulates bone growth through mechanical loading, increasing bone mineral density. This reduces the risk of stress fractures, especially during high-volume training blocks.
2. Strengthens tendons and connective tissue: Tendons respond to progressive loading by increasing collagen content and stiffness. These adaptations make them more resilient to repetitive strain, lowering the risk of tendon-related overuse injuries.
3. Improves muscular strength and running economy: Stronger muscle fibers can produce more force, which means fewer muscle fibers need to be activated to meet the demands of each stride. This lowers the relative effort and oxygen cost at submaximal running speeds.
4. Builds fatigue resistance: Since fewer muscle fibers are needed for each stride, more fibers remain fresh and available to take over when the active ones begin to fatigue. This helps you maintain posture, mechanics, and pace deeper into long runs and races.
5. Enhances neuromuscular coordination: Strength training improves the nervous system’s ability to activate muscles quickly and efficiently. This leads to smoother movement patterns, more stable joints, and less wasted energy.
6. Corrects muscle imbalances and asymmetries: Strength work (especially unilateral exercises) helps identify and correct side-to-side or movement-pattern imbalances. This promotes more efficient, symmetrical running and reduces compensatory strain.

One of the most common concerns runners have about strength training is gaining unwanted muscle mass and losing speed. The truth is: if you lift like a runner, you won’t bulk like a bodybuilder.

Muscle growth (hypertrophy) requires specific conditions: high training volume, progressive overload, and a calorie surplus. For runners, a short, focused routine is enough to build the strength that matters without compromising speed, weight, or recovery.

Strength training may not look like running, but the adaptations it creates directly support your ability to train consistently and perform at a higher level.

Coach's Tip: Resistance training is not cross-training. It supports your running, but is not a substitute for aerobic conditioning like cycling or swimming. Consider strength training as it's own unique part of the training process.

How to Structure Your Strength Workouts

There are many right ways to strength train. The body adapts to the work you give it, as long as it’s applied consistently and progressively. While some approaches may be more efficient than others, there is no single “best” way to do it.

The most important factor is choosing a structure and set of movements you enjoy and can stick with. A simple plan you’ll follow is more effective than a perfect one you’ll abandon.

There are a few principles that guide effective programs for runners, outlined below.

Try It Yourself: COROS Coaches have a program in our Strength Training article that follows these principles.

Warm-Ups

Every session should start with a warm-up. The first few minutes should be general activity to get blood flowing and joints moving. That could be a short spin on a bike, some jump rope, or light jogging, combined with some dynamic movements. If you’re coming straight off a run, you’ve already covered this part.

From there, the focus shifts to preparing for the specific movements in your session. A typical session includes 2-3 very light sets (bodyweight or just the bar at first) of your main exercise (like squat or deadlift) so you can reinforce the movement pattern without fatigue. Each set can gradually increase in load, but none should be taxing.

During these warm-up sets, you can also add a few low-intensity prep movements for other muscle groups involved in the session. Isometric holds work well here, like a Copenhagen plank or a lunge hold, as do light medicine ball throws for power-based runners. These movements fill the space between warm-up sets productively and get more of your body ready to train.

Main Session: Sets & Reps

Most strength sessions are built around one primary lift - usually a multi-joint, lower-body movement like a squat or deadlift. For power-focused athletes, a movement like a hang clean can also be appropriate here. Around that, you'll include several accessory lifts that target other key muscle groups. These help reinforce balance, coordination, and full-body strength so that nothing gets overlooked.

We recommend keeping the primary lift in the 4–6 rep range per set. Load should be heavy enough to challenge you, but still allow for clean movement and good control. This is the rep range where most of the key benefits for runners happen. Muscular endurance, as it applies to running, is already highly trained through your actual run training. You don’t need to chase it again in the gym with high reps.

Do 3 to 4 total sets, resting 90 seconds to 2 minutes between sets, depending on load and experience.

Coach's Tip: Notice that bench press is not mentioned as a primary focus. While it is a great multi-joint movement, it targets secondary muscles for running. For that reason, we don't like to make it the main lift of the workout. If you enjoy the movement, a variation of bench press fits nicely as an accessory lift.

Accessory lifts follow the same general principles but use a slightly higher rep range of 5-8 reps per set. One time-saver during the accessory movements is to choose movements that target different areas, so that one muscle group can recover while you work another. This limits the need for long rest periods and keeps the session flowing.

While the lower body is crucial, don’t neglect the other muscle groups. Running is a full-body movement. A strong and stable back, chest, core, and arms all contribute to efficiency and control. Try running with your arms by your sides and you'll immediately feel how much your upper body does. Aim to cover all major muscle groups over the course of each training week.

Using Your COROS Watch for Strength Training

COROS watches have a built-in Strength Training mode designed specifically to support your gym sessions. You can build structured strength workouts in the COROS app or Training Hub, then send them directly to your watch. During the session, the watch will guide you from one set to the next, allow you to log weight and reps after each set, and track heart rate throughout. Afterward, you’ll get a detailed summary that includes muscle groups worked, heart rate zones, and total duration.

Why do strength training activities produce low Training Load scores? Training Load is highly accurate for all endurance activities that stress your cardiovascular system. However, this system has not been designed to accurately estimate the load for strength or power activities that stress your neuromuscular system.

COROS includes a library of exercises, each with an on-screen avatar and brief movement description. If your preferred movement isn’t in the default library, you can create your own custom entry with a short description (though custom movements won’t include the avatar).