1. Increase in speed

Strength training will make you faster. Whether you are a short distance runner or a longer distance runner, you will find your pace increasing when you start strength training. Strength training will increase leg strength and improve your body’s efficiency to use energy and oxygen.

Increasing the body’s ability to use oxygen efficiently is a primary goal of endurance training, and it is measured by VO 2 max, or maximal oxygen uptake. Simply, if you can decrease the amount of oxygen needed to run at a certain speed, you’ll be able to sustain a fast pace for a longer time and likely be able to run faster overall.

2. A greater push from the ground

A heavy lower body strength training program will make you faster because you’ll be able to generate more force when you kick off the ground. Combined with better running economy and the ability to use energy more efficiently, you’ll have a better  push off the ground.

One reason strength training will increase your speed is that you’ll increase your proportion of type II . Muscle fibers that fatigue slowly and are able to produce speed and power. The type II fibers are the “fast-twitch” fibers and sprinters have a large concentration of them because their training triggers the development of these fibers.

3. Reduction in body fat

Strength training will help you lose fat. The bulk of energy that is burned in the body comes from your resting metabolic rate, which is a function of the proportion of lean muscle to body fat. Body fat slows that metabolic rate and produces various substances that make you fatter, including aromatase (turns testosterone into estrogen) and adipokines (slow metabolism). Muscle and lean tissue improve metabolism instead of hurting it, meaning to be a better runner (and have a better looking body), you want more muscle and less fat.

4. Prevention of injuries

Strength training will help you get rid of nagging injuries or chronic pain and help prevent future injuries. It will also help you correct structural imbalances that increase injury risk and lead to improper motor patterns. For example, the non-dominant side of the body is often weaker, which will throw your stride off.

Equally, muscle imbalances within each limb can cause problems for runners. For instance, the vastus medialis is a common weak link in the quad, and weak calves are thought to contribute to shin pain. Single-side training has also been shown to improve sprinters’ speed, and endurance athletes can benefit too.

5. Stronger core

Strength training with traditional lifts such as squats, deadlifts, lunges, and chin-ups will increase your core strength. Better core strength will help you avoid back pain and make you faster. Research shows that multi-joint movements are best to train the core musculature and improve the transfer of power from the arms to the legs.

One group of researchers recently found that core strength for running is best trained with squats and Olympic lifts, additionally, if the lower back, glutes, or hamstrings are weak or imbalanced, glute-ham raises and back extensions are ideal.