Plus, how to address them so you can get back to ache-free training.
By Jenny McCoy
One of the most challenging parts of running is dealing with aches, pains, and injuries–especially if they thwart your training. Unfortunately, it happens. A study of 253 recreational runners, published in 2023 in Sports Medicine, found that more than half of the participants wrestled with injury over the course of a year.
There are various reasons why running-related ailments crop up. But one of the most common culprits is muscle weakness. “It’s one of the first things I look at when somebody tells me, ‘oh, I have knee pain,’ or ‘oh I have foot pain,’” Ali Marty, P.T., D.P.T., a physical therapist in Las Vegas, tells Runner’s World. “It’s like, okay, let’s check your strength.”
As Marty explains it, weakness in one area forces another area to pick up the slack. This imbalance likely won’t cause issues right away—depending on the extent of the weakness and how often you run, it may not create problems for weeks, months, or even years. But eventually, the area that’s putting in overtime will reach its breaking point. And it’ll raise the alarm to your body in the form of pain or injury.
Important caveat: Weak muscles are not the only culprit behind many running injuries. Other factors—including lack of mobility, stability, and neuromuscular control—can weigh in too, physical therapist Nicole Haas, P.T., D.P.T., founder of Boulder Physiolab in Colorado, tells Runner’s World. That’s why a well-rounded training program will incorporate strength exercises, stretches, and drills that hit on all of these elements.
With that, here are five common muscle weaknesses that contribute to injuries, aches, and pains in runners. With the help of three physical therapists, we explain how these weaknesses show up in the body and, more importantly, the exercises that’ll help correct them so you can get back to running strong and pain-free.
5 Common Muscle Weaknesses in Runners
1. Glute Weakness
How it shows up: Your glutes are one of the main muscle groups that power your stride; they also help control how your foot lands. So when they lack strength, areas below these buttocks muscles—especially the knees and ankles—can take on extra force, leading to issues including runner’s knee, IT band syndrome, plantar fasciitis, Achilles tendinopathy, and Achilles tendinitis, Marty explains.
In particular, weakness in the gluteus medius (a small muscle toward the side of the butt that helps lift your leg out to the side and stabilizes the knee while keeping it in a healthy alignment), can cause your knee to cave in while you stride and ultimately lead to pain at the joint, Chicago-based physical therapist Leo Arguelles, P.T., D.P.T., spokesperson for the American Physical Therapy Association, tells Runner’s World.
Moreover, as Haas points out, research correlates weak glutes with low back pain. According to a systematic review published in BMC Musculoskeletal Disorders in 2019, a weak gluteus medius plays a major role in this connection.
Researchers say that can be due to a few factors: A weak gluteus medius leads to the inability to control the rotational and side-to-side movement of the hip joint, leading to biomechanical changes that affect pelvic positioning and stability; it causes the pelvis to drop to the unsupported side in the single-leg stance, putting extra pressure on intervertebral discs and loading of the low-back joints; and/or it can potentially cause inward twisting of the thigh bone and an inward collapsing of the knee, which can affect the back.
Single-leg glute bridge
What to do about it: Incorporate glute-strengthening moves into your routine.
Marty is a fan of the single-leg glute bridge (see photo above), which mimics running as you use just one side of your glutes at a time. Haas suggests the standing banded clamshell, which teaches glute engagement in the running pattern and fires up the glute medius, and Arguelles suggests banded lateral walks, which also strengthen the gluteus medius.
2. Hamstring Weakness
How it shows up: When you run, your hammies help bend your knee, as you bring your leg forward and they also work alongside the glutes to extend the hips during the push-off phase of the gait cycle.
When these muscles are not as strong as they need to be, our legs don’t bend as much, which makes other players—including the hip flexors and shin muscles—take on extra work. This can lead to issues including hip flexor tendonitis and the dreaded shin splints, Marty says.
Weak hamstrings can also cause the glutes to take on extra work during the push-off phase, causing glute tendinitis, she adds.
Single-leg deadlift
What to do about it: The single-leg Romanian deadlift (see photo above) is a stellar move Marty recommends for bolstering hamstring strength.
3. Calf Weakness
How it shows up: The calves help push us forward when we run, Marty explains. So when they’re weak, other lower-body muscles, like the muscles of the shins and the quads, pick up the slack. Over time, this can lead to issues including shin splints and runner’s knee.
The calves also help absorb some of the load when we land, so if they’re weak, that force gets transferred somewhere else in the foot. This can be the plantar fascia, a fibrous band of connective tissue on the bottom of the foot. This extra force can cause microtearing, inflammation, or overstretching in the plantar fascia, and lead to plantar fasciitis, Marty says.
Single-leg calf raise
What to do about it: Incorporate single-leg calf raises (see photo above), from both a straight leg and bent leg position, into your routine. This will target both muscles of the calf complex (the gastroc and the soleus), Haas explains.
She also recommends the farmer’s carry and wall squats with heel raises to target the calves (along with the feet and ankles).
4. Core Weakness
How it shows up: One job of the core is to stabilize the spine and pelvis as we run. And when parts of the core aren’t up to snuff, the diaphragm—a muscle that helps with respiration—can take on more stabilizing work than it’s designed to, which can then inhibit its ability to help us breathe effectively. This can cause challenges while breathing. For example, you may feel like you’re taking shallow inhales and like you’re running out of breath sooner than your stamina would otherwise allow for, Marty explains.
A weak core can also change the positioning of your spine and pelvis—for example, it could cause you to arch your back as you stride—which can ultimately lead to back pain and discomfort.
Bird dog
What to do about it: Incorporate core stability moves like the bird dog exercise (see photo above) into your routine, Marty says. Other options include the dead bug with a stability ball, Haas says, and both static and dynamic plank variations, Arguelles adds.
5. Upper Back Weakness
How it shows up: Running isn’t just a lower-body sport. Upper-body strength matters, too. And when you’re weak up top—specifically in your upper back—you may hunch forward as you stride, instead of keeping an upright posture.
This positioning can make it harder to breathe deeply. And it can also trigger pain in your neck and upper back, considering those areas are taking on more forces of gravity than they would if you were standing up tall.
Bent-over row
What to do about it: Bolster the strength of your upper back muscles with exercises like bent over row (see photo above). You can also do the cable row, Marty says, if you have access to a machine, or set it up at home, using a resistance band.
How to Use Strength Exercises to Avoid Weaknesses
You don’t need to wait for pain or an injury to crop up to do the exercises listed above. In fact, Haas and Marty suggest doing them proactively to reduce your chances of issues hampering your running. If you already have an established strength-training program, you can weave these exercises into your normal routine.
Not yet into strength workouts? Use the above exercises to create a circuit-style workout that you repeat two to three times a week. Do at least one move that targets each common problem area, with the goal being to do at least two to three exercises per area in each workout, Marty says.
Complete enough reps of each move so that you get to a point where you could only manage to do about two more with good form, then stop there. Repeat the circuit two to three times.
When to See a Professional
Not every running-related injury, ache, or pain can be solved with strength exercises. If you’ve suffered an acute injury—say, you fell down, or got hit by something—you should seek help from a physical therapist instead of relying on these moves.
You should also see a PT if you can’t do these exercises without pain, if you’re having pain that keeps you up at night, or if you have pain even when you’re resting, Marty says.
