Psoas/hip flexor
This can affect things in several ways. First, it can cause a forward flexed posture that can affect your gait. Also this attaches from your pelvis to your diaphragm. So overuse (most commonly associated with doing a lot of core exercises or bad posture) or not stretching can lead to inflammation in all these areas. Osteopath Manipulation (omt), massage and dry needling is how I treat this.
Diaphragm
Most importantly the diaphragm helps you breathe. The diaphragm is a large muscle that can go into spasm, like other muscles. This can happen if you have lung problems, decreased rib motion, thoracic restriction, stress, and more. This can be relieved with deep breathing techniques, Kinstretch, OMT, and massage.
Ribs and Clavicle
As mentioned above, the most important thing is getting oxygen and energy. Numerous muscles from the shoulder to the hip and pelvis attach to the ribs causing pain and decreased mobility. These can be treated with OMT, physical therapy or massage.
Sacrum
The sacrum is the pizza shaped bone between your hips and below your back. Sacral dysfunctions can lead to pain that can spread to the lower back and hips and can affect the range of motion in these areas. Without treatment, this can lead to an abnormal running gait. OMT, Acupuncture, holistic injections and physical therapy can all help.
Head and Neck
Problems here can affect your performance in many ways. Abnormal head posture and position can affect your gait and cause shoulder and mid back pain because of compensation in the muscles of the neck such as the sternocleidomastoid, the scalenes, Levator scapulae, pec minor and more. The scalenes and pecs are also accessory muscles for breathing, so if your diaphragm and/or runs are locked up, this will affect how well you are breathing. These can be fixed with breathing exercises, OMT, massage, holistic injections and more.