Open Chain Exercise

Introduction

The Kinetic Chain is a way of describing human movement and it can either be an open kinetic chain or a closed kinetic chain.  An open kinetic chain is defined as “a combination of successively arranged joints in which the terminal segments can move freely” Thus an open chain movement is when the peripheral segment/joint of an extremity is free to move.

Characteristic	Open kinetic chain exercises	Example: seated knee extension
Stress pattern	Rotary	The primary stress to the joint is rotation of the proximal tibia on the distal femur
Number of joint axes	One primary	Knee extension primarily occur in the sagittal plane
Nature of joint segments	One stationary, other mobile
Number of moving joints	Isolated joint motion	The femur remains stationary while the tibia is moving
Planes of movement	One (single)
Muscular involvement	Isolation of muscle group activation	Minimal muscle co-contraction is used to do the movement
Movement pattern	Often non-functional

Biomechanical and neurophysiological factors

OKC exercises allow for motion in the distal segment while movement is restricted to a single joint. This typically includes exercises to improve strength and range of motion. 

Characteristics of typical non-weight bearing activities: 

• Increased distraction and rotational forces
• Increased acceleration forces
• Decreased resistance forces
• Increased deformation of joint and muscle mechanoreceptors
• Increased concentric acceleration and eccentric deceleration forces
• Promotion of functional activities
• Requires agonist-antogist force couples

Exercises

Open chain exercises are beneficial to target specific muscles. Here some examples. 

Open Chain Upper-body Kinetic Exercises

Bench press
Dumbbell biceps curl
Chest-fly (using dumbbells)
Lat pull down
Tricep extensions

Open Chain Lower-body Kinetic Exercises

• Seated leg extension
• Terminal knee extension exercises
• Hamstring curl
• Plantar / dorsiflexion (calf pumps)