At some point, most trail runners will address their running form, whether by hiring a coach or gait analyst, attending a clinic or trying their best to mimic the form displayed by a personal trail-running idol. For most of us, however, our runs comprise only a small fraction of our daily activity, which means that our non-running form—our posture—actually influences our running.

Thanks in large part to modern conveniences like vehicles, technology and sedentary work, our body’s alignment has been negatively impacted. Almost all of us have postural deviations, ranging from mild to severe, and while a curved back might not seem like it could affect our running, everything is connected.

Here are three of the most common postural deviations affecting trail runners, and ways to mitigate them.

1. Forward Head Lean

What is it?

Have you ever looked down to text on a cell phone? Are you leaning your head forward and looking down at a screen right now to read this article? You’re likely perpetuating a common postural deviation known as forward head lean.

Why does it happen?

Forward head lean is proliferated by activities where your upper spine is in flexion and your head extends ahead of your shoulders. You can do a quick sideways check in the mirror to test yourself: is your inner ear directly stacked above your shoulder? If not, read on. Though forward head lean is OK for short periods of time, accumulating a lot of time in this single posture can be detrimental to your running form. Simply put, if you accumulate more time in your day looking down with a forward head than you do with your head up and properly stacked over your shoulders, you are going to develop forward head lean.

How does it impact your running gait?

The farther the head extends ahead of the shoulders, the heavier that big old melon becomes and the more your trapezius muscle strains to keep it upright. While your traps soak up the bulk of the load, the stronger muscles of the neck and latissimus dorsi are much less active than they should be. This lack of engagement in the upper back and neck often leads to an interior rotation of the shoulders; when combined with forward head lean, this posture places an unstacked and heavy load ahead of your hips. This results in an improper forward lean from the waist, often leaving the runner stumbling forward rather than properly pushing forward through space.

What can you do?

Fixing it is a two-fold solution: first, loosen tight muscles. Then, strengthen your lats and neck muscles. Activation of the upper back muscles through exercises like band pull-aparts combined with exercises like leaning your back of your head against a wall and “pushing” your head back into the wall are great ways to start. No matter how much time you spend stretching, however, if you still spend the majority of your day with your head in a forward-head-lean position, you probably won’t solve the issue. Instead, become mindful of your posture and sit and stand up straight.

2. Anterior Pelvic Tilt

What is it?

Ever notice how stiff you feel after sitting for a long period of time, particularly with rounded shoulders and a back that looks rounded? Unless you’re sitting tall and straight, you’ve likely incited some degree of an anterior pelvic tilt. If we picture the pelvis like a bucket full of water, an anterior pelvic tilt occurs when muscles in the front of your body (anterior) pull tight on the pelvis, causing that water to spill over the front of you. Spilling water in this manner when you run, walk or even stand can have profound effects on your trail running.

Why does it happen?

Anterior pelvic tilt is an issue of muscular imbalance. Although the imbalance can be athletic in origin, it is usually the lack of movement in non-training hours of the day that cause it in the first place; running then magnifies whatever pelvic rotation was already there. If you accumulate a large amount of time in a seated position, like driving, and pay little attention to posture, you likely have some degree of inactive glutes, inactive deep core muscles, tight lower back muscles, and tight hip flexors, all of which contribute to an anterior pelvic tilt.

How does it impact the running gait?

Anterior pelvic tilts create tight hip flexors (the muscles to the left and right of the groin), which results in the tendency for a runner to bend at the waist. Unfortunately, this often produces poor hip extension and an overemphasis on hip flexion.

What can you do?

The anterior-tilted pelvis is the amalgamation of tight lower back muscles, tight quadriceps and tight hip flexors. In order to reverse this, a two-fold approach is needed. First, begin to loosen the tight muscles with self-myofascial release, massage or active release. Second, begin to strengthen the muscles that counteract the tight muscles, which include the hamstrings, glutes and the deep core muscles.

3. Tight Ankles

What is it?

Trail running requires ankle mobility, and a lot of it. Whether sweating through an incredibly steep climb at the Western States 100 or bombing long, technical downhills at Ultra-Trail du Mont-Blanc, flexible, strong ankles are paramount for good running mechanics.

Why does it happen?

Sedentary positions propagate a lack of ankle mobility. Think standing or sitting for long periods of time without much movement or flexibility. A lack of challenging terrain (for example, always choosing to run on pavement, smooth trail or sidewalks) further creates ankle weakness. In terms of ankle mobility, the old saying “use it or lose it” is very accurate.

How does it impact the running gait?

Lack of ankle mobility can lead to an almost overwhelming amount of compensations. If you lack dorsiflexion (think trying to make your big toe touch your shin) during your run, your foot will begin to over pronate, leading to the inward collapse of your knee. If you lack range of motion in eversion and inversion (think moving your foot side to side), you’re often at risk for an ankle sprain or worse, a foot fracture.

What can you do?

In order to correct this issue, proper strength work is needed. This can be done simply with a band. Specific exercises include the curb stretch, sitting on your feet (called the kneeling pose in yoga) and performing banded-ankle distractions.

—Jade de la Rosa is a freelance writer, M.F.A. candidate and ultrarunner.

—Nickademus de la Rosa is a trail-running coach and gait analyst.