Here is a reference page for you guys with the definitions of some of the more technical terms you may find throughout this site. If any of these are still unclear after reading, shoot me a comment!
Agonist – Muscle that is the prime mover of a certain motion.
Antagonist – A muscle that opposes the motion/action of the agonist muscle (ex: triceps are the antagonist in elbow flexion.)
Arthrokinematics – Referring to motion at a joint.
Co-contraction – Muscles that contract together in order to accomplish a desired motion.
Contralateral – Referring to the opposite side of the body.
Dyskinesis – Improper movement pattern at a joint due to lack of muscular control or poor positioning. (Often used to describe improper mechanics at the scapula.)
Fascia – “sheet like” connective tissue that covers muscle tissue and divides it into compartments. (Muscle can often become adhered to the fascia and alter movement patterns. Self-myofascial release techniques like foam rolling aim to correct this.)
Force Couple – Two or more muscles working together to accomplish a certain motion. (Ex: During shoulder flexion the upper trapezius, lower trapezius, and serratus anterior all work together to create optimal scapular positioning.)
Hypomobility – Lack of normal motion.
Inhibition – Decreased activity of a muscle (more detail under reciprocal inhibition.)
Ipsilateral – Referring to the same side of the body.
Kyphosis – Outward curve of spine. (some degree of kyphosis is normal in the thoracic spine, but excessive kyphosis becomes problematic.)
Length-Tension Relationship – The resting length of muscle fibers and how that relates to force production. (Every muscle has an optimal length where it can produce the most force. When muscles become shortened or lengthened in their resting position, we get altered length-tension relationships.)
Lordosis – Inward curve of the spine.
Lower Crossed Syndrome – Imbalance of hip and lower extremity musculature. Characterized by a forward tilt of the pelvis, and improper length and recruitment of lower extremity muscles.
Reciprocal Inhibition – Relaxation of one muscle group in response to the activation of the opposite muscle group. (Ex: Relaxation of the hamstrings in response to activation of the quadriceps)
Synergist – A muscle that assists the primary muscle in creating a desired motion. (Ex: the anterior deltoid is a synergist to the pectoralis major during a push-up.)
Synergistic Dominance – When the synergist (or muscle responsible for assisting) becomes the primary mover in a certain motion. (This is often seen in the upper trapezius and iliopsoas. Posture can play a large role in developing synergistic dominance.)
Upper Crossed Syndrome – Improper upper body positioning that usually presents with rounded shoulders and forward head posture. (This tends to lead to tightness in the pectorals and lengthening of the rhomboids and mid trapezius.)