The upper back, known as the thoracic spine, is often overlooked by runners who focus primarily on leg and hip mechanics. This area includes the twelve vertebrae between the neck and the lower back, providing attachment points for the rib cage and stabilizing the trunk. Although running is lower-body focused, the upper back maintains upright posture and facilitates the counter-rotation of the torso that balances the arm swing. Soreness in this area after a run is a common symptom pointing to underlying mechanical or muscular inefficiencies. Understanding the demands placed on the thoracic spine helps pinpoint the source of discomfort.
Primary Musculoskeletal Causes
Soreness often originates from inefficient running posture, forcing the stabilizing muscles of the upper back to work overtime. When the head drifts forward, it places excessive strain on the upper trapezius and levator scapulae muscles that attach to the neck and shoulders. This forward head position increases the load on the upper back muscles.
Holding excessive tension in the shoulders, often accompanied by a forward-slouched posture, is another direct cause. This rounded posture lengthens and weakens the middle and lower trapezius muscles and the rhomboids, which retract the shoulder blades. When these muscles are fatigued, they can develop trigger points or spasms resulting in aching pain felt between the shoulder blades.
Improper arm swing also contributes to upper back strain, especially when the arms are held too rigidly or swing across the body’s midline. Arms should swing primarily forward and backward to balance the rotational forces from the lower body. When arms cross the chest, the upper back muscles must constantly fight this horizontal motion, leading to localized fatigue and soreness.
Underlying Muscular Imbalances
Soreness in the thoracic spine is often a compensation pattern stemming from weaknesses in other parts of the body, particularly the core and hips. If the deep abdominal and lower back muscles are weak, the pelvis and lower trunk lose their primary source of stabilization.
This lack of central stability causes the upper body to compensate, often resulting in excessive rotation or reliance on the smaller muscles of the upper back to steady the torso. When deep core muscles, such as the transversus abdominis, are insufficient, superficial muscles like the longissimus thoracis are forced to over-engage, leading to strain higher up the spine and muscle fatigue.
Weakness in the gluteal muscles and hips also indirectly affects the upper back by failing to control the pelvis. Weak glutes cannot adequately stabilize the pelvis during the single-leg stance phase of running, causing it to drop or rotate excessively. This rotational strain travels up the spine, forcing the upper back muscles to act as secondary stabilizers. Addressing hip and core weakness removes the compensatory burden placed on the thoracic muscles.
Equipment and Environmental Factors
External factors related to gear and surroundings can contribute to upper back soreness. Carrying weight, such as a phone or a poorly fitted hydration pack, shifts the center of gravity and requires constant muscular effort. Even a lightweight pack, if improperly adjusted, can bounce and cause repetitive micro-trauma or place direct pressure on the upper back muscles.
For women, the fit of a sports bra is a common contributor to discomfort. Bras with narrow straps, high tension, or those too tight around the rib cage restrict the natural movement of the thoracic spine and shoulder blades. This restriction forces the body to alter its arm swing and posture, resulting in localized muscle fatigue and pain.
Cold weather can also trigger muscle tension. Running in the cold often causes a subconscious shrugging of the shoulders, which activates and tightens the upper trapezius muscles. Maintaining this contracted position leads to muscle soreness felt after the activity.
Strategies for Relief and Prevention
Preventing upper back soreness requires improving running form and strengthening the supporting musculature. For form correction, periodically check posture while running by imagining a string pulling the top of the head upward, promoting a “running tall” feeling. Runners should also focus on relaxing their shoulders, intentionally letting them drop away from the ears to reduce tension in the upper trapezius.
Strengthening and Mobility
To address underlying weaknesses, specific resistance training exercises are effective. Incorporating core stability exercises, such as planks and bird-dogs, helps build the foundational strength needed to stabilize the trunk and reduce the burden on the upper back. Strengthening the posterior shoulder chain is equally important, using exercises like face pulls and bent-over rows.
Face pulls engage the muscles responsible for shoulder external rotation and retraction, directly countering the rounded-shoulder posture common in runners. Mobility work focused on the thoracic spine also provides relief. Using a foam roller to perform extensions helps restore segmental movement and counteract stiffness. Stretching the chest and front of the shoulders, often using a doorway stretch, helps release the tight pectoral muscles that pull the shoulders forward.
It is important to recognize when the issue requires professional attention. Persistent pain that radiates into the neck or down the arm, numbness, tingling, or pain present even when not running should be evaluated by a physical therapist or physician. These symptoms can indicate nerve impingement or a more serious spinal issue requiring specialized treatment.