Some runners shun strength training for fear that they’ll develop a body-builder’s physique and no longer be able to run well. While it’s true that huge muscles are detrimental to running, at least in endurance events, you really don’t have to worry about spontaneously gaining tens of pounds of bulging meat. It’s not going to happen by accident! You can absolutely increase strength in ways that will add minimal mass and that will improve your running.

Why to Build Strength

Research shows that if you increase strength in relevant ways, you can improve the efficiency of your stride, become more resistant to overuse injuries, and become more resistant to fatigue.

How Training Increases Strength

All strength building is based on loading muscles beyond what they’re accustomed to, and then allow them to recover. During recovery, muscles strengthen partly through hypertrophy, which means increasing the amount of contractile muscle fiber (also known as getting bigger). They also strengthen by way of increases in neuromuscular efficiency, which has to do with how well the nervous system is able to recruit muscle fibers for a specific task.

Hypertrophy comes with some tradeoffs-you have to supply oxygen to those bigger muscles, and you have to carry them! But a little hypertrophy goes a long way, if your training is efficient.

Gains in neuromuscular efficiency come with no tradeoffs whatsoever. And these gains come quickly, especially in a new training program.

How to Build Strength for Running

There are many choices to make when designing a strength-training program: which muscles? What range of motion? How much resistance? Free weight, bodyweight, or machine? How to decide when to end a set? How many sets? How many workouts per week?

There’s no scientifically certain right answer; only general guidance. The most important principle is specificity-you will build strength through the range of motion that you train, and you will build strength of a type that corresponds with the way you train. For example, to build explosive strength, like for jumping, you should train with heavy weights. And you should train with an emphasis on moving the weights as fast as possible during very short sets, like two to three repetitions. To train for longer expenditures of strength, like for rock climbing, you should train with lighter weights, which allow sets of eight to twelve repetitions.

For distance running, you’re preparing muscles lower intensity, longer duration activity. So consider repetitions in the range of 12 to 20 repetitions, with lighter weights.

How Light is Light? How Heavy is Heavy?

This varies from individual to individual, from muscle to muscle, and over the course of your training, from week to week. Here’s a basic guide:

Heavy: weight that you can lift, in perfect form, between 1 and 4 repetitions. 90–100% your one-repetition maximum.

Medium-Heavy: weight that you can lift, in perfect form, between 5 and 7 repetitions. 80–90% your one-repetition maximum.

Medium: weight that you can lift, in perfect form, between 8 and 12 repetitions. 70–80% your one-repetition maximum.

Light: weight that you can lift, in perfect form, between 13 and 20 repetitions. 60–70% your one-repetition maximum.

Very Light: weight that you can lift, in perfect form, more than 20 repetitions. 60% your one-repetition maximum and below.

Most lifting for distance running should be done in the Light zone. Very Light can be useful as well-but counterintuitively, workouts that use weight in this range are extremely draining. With weights that allow a set of 20 reps or fewer, you have to sustain a burning sensation for just the last few repetitions. But if you’re lifting, say 40% your one-repetition maximum, and doing sets of 50, you may have to sustain the burn for half of a set that can go on for well over a minute. It’s mentally taxing, and can lead to increased soreness. So generally speaking, we recommend working in the 12 to 20 repetition range.

How to Know When a Set is Finished?

The old wisdom was to train to “failure,” which is the point at which you absolutely can’t do another rep. Research now shows that this is unnecessary. If you come within a rep or two of failure, you’ll get almost all the benefit, but with less exertion, less pain, and a quicker recovery. This is great news. You don’t have to give it everything you’ve got. Just give it most of what you’ve got!

How Many Sets?

You will get some benefit from a single set. You’ll get more benefit from two or three sets, with at least a couple of minute’s rest between. After three sets, the benefits diminish greatly. Athletes doing 5 to 8 sets are usually body-building or are training for very strength-specific sports. This isn’t relevant to running, so please, don’t go crazy with this kind of extended routine.

How Many Times a Week?

You’ll get benefits from one workout a week. You’ll get greater benefits from two or three, depending on how quickly your body recovers. This will vary with your genes and your age. Some people can train a muscle four times a week; others can only get away with twice a week.

You probably have limited training time, and running will always be more important than weights. Some runners choose to weight train 2 or 3 times a week in the winter, when their running mileage is low, and then back off to once a week during the spring and summer season.

Which Exercises?

Number one on the list is free-weight squats. These work almost the entire lower body, as well as the lower back, and when done properly help strengthen all the joints involved. They have the benefit of working all your stability and balance muscles, and of working your muscles through a longer range of motion than they ever get from running.

Calf raises, either free-weight or machine, fill in for the one muscle group neglected by squats.

SIt-ups or crunches, including incline crunches, are good for abdominal strength, and help keep your trunk muscles in balance.

If you run on trails and need stability on uneven or slippery surfaces, consider the hip abductor and adductor machines. Also consider various types of box-jumping.

You may choose to do an upper body workout as well, but it’s optional for running. Ideally, emphasize multi-joint exercises like bench press / push-ups, and pull-ups.

Why is Good Form Important?

So you get the full benefit of the exercise and so you don’t get hurt. Especially for the free-weight exercises, like squats, we strongly suggest that you book an appointment with a professional trainer, who can teach you all the subtleties of proper form. You’re not going to learn this from a blog!

If you don’t have access to a trainer, you can find resources online that include videos. It’s also a great idea to work out with an experienced friend, so you can spot each other and watch each other’s form.

In Closing

There’s no need to fear the weight room. Just be sure to approach it wisely, so you don’t get hurt. And be sure to keep it in perspective, so it supplements your running routine rather than taking it over. Be strong!