Open Kinetic Chain, Closed Kinetic Chain, and Plyometric Strengthening Exercise

Question 1

Intro

Answer 1

• the concept of specificity is amongst most important in training and rehab
• training and rehab tasks must mirror functional activity (especially advanced training or rehab)

Question 2

Steindler and Kinetic Chain Terminology

Answer 2

• described human motion as rigid overlapping segments of limbs, limbs connected by series of joints
• defined kinetic chain as combo of several successfully arranged joints; constituting a complex motor system
• observed changes in muscular recruitment and joint motion-lesser forces needed when had or foot free to move

Question 3

Kinetic Chain Terminology

Answer 3

• most common contemporary description of CKC exercise: terminal segment of appendage fixed
• most common contemporary description of OKC exercise: terminal segment of appendage free to move
• many activities do not neatly fall into one category

Question 4

Characteristics of OKC Exercise

Answer 4

• distal segment is free
• can produce isolated joint motion
• movement occurs on only one side of joint
• muscle functions to accelerate or decelerate isolated joint motion

Question 5

Characteristics of CKC Exercise

Answer 5

• distal segment is fixed
• involves multiple joint motion
• simultaneous motion of distal and proximal segments
• muscle function used to both stabilize and move multiple segments

Question 6

Fundamentals of OKC and CKC Exercise

Answer 6

• can include each form: isometric, isokinetic, isotonic
• physiological basis for OKC based on length-tension physiology
• advantages and disadvantages for each
• weight pros and cons when prescribing

Question 7

Fundamentals of OKC Exercise

Answer 7

• exercise occurs thru available ROM
• useful for isolating: muscle or muscle group; joint specific motion
• lesser metabolic cost than CKC or plyometric exercise

Question 8

Advantages of OKC Exercise

Answer 8

• may be used when client cannot properly bear weight on body part
• client has poor technique when bearing body weight
• client needs to isolate proximal stability prior to distal function

Question 9

Disadvantages of OKC Exercise

Answer 9

• joint reaction forces are different than in most functional activities
• muscle firing patterns differ from CKC exercise
• OKC exercise must be used with caution in some conditions: may increase patellofemoral compression and ACL tensile load; use with caution in these areas of knee rehab
• poor predictor of success with functional activities

Question 10

Clinical Implications of OKC

Answer 10

• generally superior for isolating specific muscle
• should be employed in tandem with load bearing exercise particularly for LE
• limited capacity to prepared individual for stretch-shortening loads of many functional activities

Question 11

Physiological Basis for CKC Exercise

Answer 11

• often chosen when professional wants to stress joint in weight bearing position
• joint loading provides mechanoreceptors with proprioceptive information critical for coordination
• proprioception arises from activation of afferent neurons located in joint capsule, ligaments, surrounding muscle
• co-contraction of agonists and antagonists is more apparent in CKC than OKC
• proprioceptive and muscular co-contraction play complimentary role in neuromuscular basis of motion muscular force-couple interaction allows for max joint congruency and inherent joint stability and the force-couple dependent upon adequate intensity and timing
• mechanoreceptors are cooperatively responsible for neuromuscular control of joint: within static and dynamic structures, functional optimally when in load bearing position

Question 12

Advantages of CKC Exercise

Answer 12

• integration of multi-planar muscular actions: isometric, concentric, eccentric
• integration of strength, balance, and motor control
• replication of functional loads and activities
• increased joint stability secondary to muscular co-contraction
• decreased shear forces at tibio-femoral joint

Question 13

Disadvantages of CKC Exercise

Answer 13

• may be more difficult to stay within pain-free ROM for those clients with pathology
• lesser isolation of specific muscles
• difficult to prevent compensation in HEP
• may not prepare individual for OKC function or dissimilar CKC activities

Question 14

Clinical Implications of CKC

Answer 14

• weight bearing increases joint compression forces
• due to summation of ground reaction forces increased neuromuscular control
• increased neuromuscular control increases joint stability during functional activities
• individual relies on these to dissipate ground-reaction forces: muscular co-contraction, eccentric muscular control
• critical during many daily and sport-specific activities: walking, running, jumping, cutting
• most individuals benefit from proprioceptive and neuromuscular stimuli associated with CKC
• obvious correlations exist between squatting and transfers, etc and step-ups or downs and stair climbing

Question 15

Plyometrics

Answer 15

• shock or jump training
• involves quick powerful movements involving a prestretch of muscle
• thus activating the stretch shortening cycle
• eccentric contraction followed immediately by concentric contraction
• linked to increased neuromuscular coordination and neural efficiency
• goals of this type of training include: increased excitability of neurologic receptors controlling movement and increased reactivity of the neuromuscular system
• consensus exists on value but controversy exists regarding optimal training routines
• may be used to enhance specificity such as: activities requiring max muscular force in min time or activities minimizing metabolic energy costs
• specific plyometric exercises provide a transitional training; to explosive movements of many functional and sporting activities

Question 16

Physiological Basis for Plyometric Exercise

Answer 16

• stretch-shortening exercises: use elastic and reactive properties of muscle, generate max force production
• employ proprioceptive stimulation to facilitate increase muscle recruitment and decrease muscle recruitment time
• muscle spindle fibers provide proprioceptive basis for stretch-shortening exercise
• elastic recoil of tissues allows positively influenced
• velocity of stretch stimulates muscle spindle fibers duration of stretch stimulates GTO-tension force (prolonged stretch and prolonged isometric contraction

Question 17

Phases of Plyometric Exercise

Answer 17

• setting or eccentric phase
• amortization phase
• response or concentric phase

Question 18

Setting or Eccentric Phase

Answer 18

• begins when individual mentally readies
• ends when stretch stimulus is initiated within the neuromuscular system
• advantages of this phase: increased activity of muscle spindle fibers, positive bias alpha motor neuron unit for optimal action
• duration determined by impulse
• too much impulse –> increased time between eccentric and concentric phases; prevents optimal exploitation of stretch shortening cycle

Question 19

Amortization Phase

Answer 19

• aka electromechanical delay between eccentric and concentric actions: begins with eccentric phase wanes, ends when concentric action starts
• successful plyometric training relies heavily on rate of stretch rather than length of stretch
• slow amortization phase wastes elastic energy as heat minimizes stretch reflex
• more powerful response depends upon quickness of transition and yielding work to overcoming work

Question 20

Response or Concentric Phase

Answer 20

• individual completes the concentric action
• considered “payoff phase” secondary to increased yield: greater force production secondary to potentiation of MSF
• relies partly on increased inhibition of GTO response: GTO desensitized through plyometric training

Question 21

Clinical Implications: Plyometrics

Answer 21

• teaches NM system to better accept and apply increased system loads
• stretch-shortening reflex allows muscle to perfom with max concentric force, decreased metabolic demands
• use in advanced training and rehab programs
• used to train for specific applications: sport, work, ADLs
• may be integrated into UE as well as LE activity: needed in many activities, gymnasts, boxers, football players, wrestlers

Question 22

Integrating OKC, CKC, and Plyometrics into Exercise Prescription

Answer 22

• lean toward an “endurance bias”: start with low load, increase reps before load, reinforce NM integration (technique) before height loads
• considering the “intensity hierarchy”: joint stability/weight bearing status hierarchy, muscular load hierarchy, neuromuscular load hierarchy, metabolic load hierarchy
• generally the higher the intensity the greater the recovery needs