
A biomechanical concept that is commonly used in functional training involves the proposition that the body’s joints make up a kinetic chain in which each joint represents a link. Drawing on this principal, exercises may be described as either open- or close-chain movements.
In an open-chain exercise, the end of the chain farthest from the body is free, such as in a seated leg extension. Open-chain exercises tend to involve more shearing forces at the joints, while closed-chain exercises tend to emphasize compression of joints, which helps stabilize the joints. Additionally, closed-chain exercises involve more muscles and joints than open-chain exercise, which leads to better neuromuscular coordination and overall stability at the joints.
Optimal performance of movement requires that the bodies muscles work together to produce force while simultaneously stabilizing the joints. Typically, people with weak stabilizer muscles will exhibit problems with performing proper, efficient movement, which may lead to pain and/or injury.

⦁ In open kinetic chain exercises, the segment furthest away from the body — known as the distal aspect, usually the hand or foot — is free and not fixed to an object. such as a seated leg raise where the foot is not in contact with anything.
⦁ In a closed chain exercise, it is fixed, or stationary such as squats where the feet are in a fixed position on the floor. often incorporated into rehabilitation and post-rehabilitation programs that focus on the body’s stabilizing musculature. (e.g., deep abdominals, hip stabilizers, scapula retractors)
⦁ closed chain exercises tend to emphasize compression of joints, which helps them to stabilize, whereas open chain exercises tend to involve more shearing forces at the joint.
⦁ closed-chain exercises involve more muscles and joints than open chain exercises, which leads to better neuromuscular coordination and overall stability at the joints.
An example of a program that develops functional strength and range of motion is a conditioning routine that incorporates squats, lunges, multidirectional reaches, and overhead presses.