What Muscles Does Running Work? Key Muscle Groups and How to Strengthen Them

Running is one of the simplest ways to build strength, stability and endurance using only your body weight. But what muscles does running work, exactly? Understanding the muscles used in running, from your quads and hamstrings to your glutes and core, can help you run more efficiently, reduce injury risk and improve performance.

Each stride activates major lower body and core muscles, along with stabilisers that maintain posture and balance. Knowing the muscle groups worked while running or jogging can also help you identify weaknesses before they turn into pain.

Here's a quick overview of the primary muscle groups involved:

• Hip flexors (iliopsoas and rectus femoris) lift the leg and drive the knee forward.
• Quadriceps (rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius) extend the knee and control impact.
• Hamstrings (biceps femoris, semimembranosus, and semitendinosus) extend the hip and power forward movement.
• Glutes (gluteus maximus, gluteus medius, and gluteus minimus) generate force and stabilise the pelvis.
• Calves (gastrocnemius and soleus) store and release energy for push-off.
• Core (rectus abdominis, obliques, and erector spinae) control rotation and support posture.
• Upper body muscles (latissimus dorsi and deltoids) assist balance and contribute to momentum.

These are the primary muscle groups running works, regardless of pace or terrain.

It's helpful to be aware of the running gait cycle (how your legs move with each step) to better understand how your muscles work when running. There are two main phases, per research published in the International Journal of Physical Education, Fitness and Sports:

• Stance: when one foot is on the ground
• Swing: when one leg travels forward in the air

Muscles alternate between absorbing force, stabilising the body, and generating forward movement throughout each cycle.

Below, we take a closer look at the muscles used in running and the role each plays.

The hip flexors, including the iliopsoas and rectus femoris, comprise a group of muscles in the front of the upper thigh that flex (bend) your hips. They drive the leg upward and forward for efficient stride mechanics.

They contract during the swing phase and lengthen as the leg extends behind you. They work even harder during hill running and sprints.

Because the hip flexors repeatedly shorten during running, tightness is common. According to Schuyler Archambault, P.T., D.P.T., C.S.C.S., a physical therapist and personal trainer at Arch Physical Therapy and Fitness in Boston, sitting a lot during the day also puts the hip flexors in a shortened position, which can worsen tightness.

Tightness in the hip flexors could limit how far you're able to extend your hips while running, which also limits how much help you get from your glutes.

Your glutes include three major muscles. The gluteus maximus is the largest, and it produces powerful hip extension, while the gluteus medius and minimus stabilise the pelvis during each stride.

The gluteus maximus is especially active during sprinting and uphill running. A 2021 study in Medicine & Science in Sports & Exercise found this muscle to be significantly larger in elite sprinters.

The glute med and glute min prevent the pelvis from dropping when the opposite leg is off the ground.

"Whenever the opposite leg is off the ground, the glute med has to work hard to keep the pelvis level so that you don't fall to one side, because, with one leg off the ground, gravity is at work to throw you off balance," said Luke Bennett, D.C., CSCS, a chiropractic doctor who works with runners at TOPTEAM Sports Performance in North Carolina.

Strong glutes improve alignment, power and running economy.

The quadriceps (quads) are a group of four muscles that include the rectus femoris, vastus lateralis, vastus medialis and vastus intermedius. They manage impact forces and extend the knee during push-off.

They also help lift the knee during swing and stabilise the joint during landing. Downhill running increases demand on the quads dramatically, because they have to perform strong eccentric contractions (when the muscle lengthens) to help control your speed.

"It's a lot of work to put the brakes on to control your movement so that you don't just fall on top of yourself," Dr Bennett said. This braking can increase soreness and requires substantial quad strength.

The hamstrings, including the biceps femoris, power hip extension and contribute to movement during the stance phase.

They bend the knee during the swing phase but play a bigger role in forward motion and acceleration. A Frontiers in Physiology study found that men with the highest hamstring activation produced the greatest amount of force during sprints.

Some runners, especially females, tend to be "quad dominant", meaning their quadriceps take on more of the workload than the hamstrings. If your hamstrings aren't strong enough to contribute equally to your running stride, your quads have to work harder to pick up the slack.

According to Dr Bennett, "At some point, you may notice your knees hurt from running".

Balanced hamstring strength helps prevent knee strain and improve stride efficiency.

The calf muscles in your lower legs are also key players during the running gait cycle. The gastrocnemius and soleus generate high levels of force and store elastic energy for push-off.

After the foot contacts the ground, the calves and Achilles tendon absorb and store energy. During push-off, they release that energy to propel you forward.

If your calf muscles aren't strong enough to absorb that force and release it during push-off, your body will compensate in ways that limit power and increase your injury risk, Archambault said.

The rectus abdominis, obliques and erector spinae connect your upper and lower body and stabilise the trunk to improve efficiency of movement. These muscles minimise rotation so your legs can drive straight ahead without everything swaying.

"Those muscles are working hard to control rotation so you don't waste energy twisting back and forth", Dr Bennett explained. They also support the spine, helping maintain balance and alignment.

While running relies mostly on your lower limbs, your upper body is involved, too. Your arms naturally swing while running (or walking). The latissimus dorsi and deltoids assist arm swing, which contributes to balance, rhythm and forward momentum.

Arm drive helps counterbalance leg motion and maintain posture. Your back and shoulders also play a key role in maintaining an upright posture throughout your run, which can enhance your running economy.

"By maintaining an upright posture, you maintain alignment to ensure the most efficient transfer of energy through the body", Archambault said.

Running strengthens muscles, but the type of strength depends on the type of running. Running builds muscle by improving:

• Muscular endurance
• Tendon stiffness and elasticity
• Neuromuscular coordination

However, running does not typically build large muscle mass. Building muscle is more associated with strength training, hill sprints and explosive running.

For balanced strength, runners benefit from supplementing their mileage with resistance training.

• Higher activation of gluteus maximus, hamstrings and calves
• Greater core stabilisation
• More powerful arm swing

• Increased glute max and calf activation
• More hip extension and knee drive (rectus femoris and iliopsoas)
• Higher force output in every stride

• More work from stabilisers: glute med/min, obliques and deep foot muscles
• Increased eccentric quad demand
• Enhanced core engagement for balance

Running stresses the same tissues repetitively, so progress gradually, rotate terrains and intensities and listen to early signs of discomfort. If you experience persistent pain, consult a physical therapist to evaluate your strength, gait mechanics and mobility.