Strength Training for Runners - What Muscles and Why are They Important?

Marathon training is no walk (or run for that matter) in the park. It is very time consuming and takes a great deal of commitment. So I understand that adding strength training for runners to your already lengthy runs better be for good reason. Well it does meet the "good reason" qualifications checklist and here's why!

I've trained for marathons before without doing any strength training and then with doing strength training for runners. As a beginner marathoner it is not as essential as you mainly want to focus on the race and just finishing by building mileage through your long runs. However when I did incorporate strength training I really and truly noticed the positive difference.

I have mentioned the benefits and results, previously but runners like details so here is a breakdown of what muscles runners should not be ignoring in a strength workout and why these muscles are important as a runner.

Strength Training for Runners: Which muscles to focus on!

Feet Muscles

Good thing our feet can't go on strike or they just might! On the impact of the foot striking the ground, our feet are given 2-3 times the weight of our body. Basically they take a full beating! It goes without saying that strength in the feet is imperative for warding off injuries that are common due to weak feet (and of course other issues)  such as plantar fasciitis and shin splints.

Shin Muscles

The shin muscles do not develop fast enough from running and so are often overpowered by the strong calf muscles that are behind them. Strengthening these shin muscles will allow the muscles to become more balanced and prevent injuries like plantar fasciitis, stress fractures and especially shin splints which are so common in runners.


Our calves, which are made up of the gastrocnemius and the soleus muscle, are responsible for flexing our leg (bringing it up toward the butt) and for plantar flexing the foot (point the foot downwards) – two very important movements in our running stride. Running strengthens these muscles very quickly and not much strength training is called for as runner however some is good for preventing such injuries as Achilles Tendonitis and plantar fasciitis.  Strong calves also will help to prevent ankle injuries by providing stability.


The quadriceps are the group of muscles on the front of the upper leg above the knee. Like the shins, they develop slow from running and are can cause us problems as the hamstrings (right behind the quadriceps) develop at a fast rate when running. Weak quadriceps can lead to the ever forbidding Runner's knee as one of their main functions is to stabilize the knee. They also are responsible for absorbing the impact during a running stride. Strength in these muscle is crucial!


The hamstrings are located in the back of the upper leg and are responsible for the eccentric work (high force producing work) while running. During the running stride, the hamstrings go from acting as a knee stabilizer to extending the hip rapidly which can cause enormous amounts of strain. Running does strengthen the hamstrings quite a bit and so, like the calves, not much strength training for runners is required of them.

Core Muscles

The core comprises the muscles of the hips, pelvis, lumbar (lower) spine and the abdominal muscles. It is where our center of mass is located and for a runner is more important than one might think. The most valuable asset of a strong core is the ability to maintain proper form and stability during later miles of a run or race when the body is starting to fatigue.

Strong abdominals can counteract the force on the lower back which can become tense from pressure during long runs. Weak hips and pelvis can lead to a host of running issues including stress fractures which are quite common in distance runners, especially women runners.

Upper Body Muscles

I will group the upper body together since although they are important, they are not the powerhouses of running. The upper body consists of the arms, shoulders, chest and back. Like the core, the strong upper body will aid in form maintenance in high mileage runs. It really can make all the difference when trying to set a PR or place in a certain category to have a strong upper body as it will also help in stiffness that builds up and in dealing with the fatigue of the marathon.

The arms in particular are important for balance and form maintenance.  An added bonus to arm strength is that there is a direct correlation between speed of arm swing and leg speed. So bottom line is strong arms will give you that kick to the finish line!

Takeaway Points for Strength Training for Runners

  • A strong runner leads to stronger, faster running. It is well worth the short amount of time that a strength workout demands.
  • The quadriceps and the shins develop at slower rates than the hamstrings and the calves and so as far as leg strengthening exercises go these should be emphasized more.
  • Do not ignore the upper body if you are looking to take your running to the next level!

Enjoy your strength training for runners program! It really will serve you well!

See here for more on Strength Training for Runners + Training Plans

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