Amortization Phase
Amortization Phase: The amortization phase is the brief transition period between the eccentric (muscle lengthening) and concentric (muscle shortening) phases of a stretch-shortening cycle (SSC) during high-velocity (power ) movements. It is the momentary isometric contraction that occurs as the muscle switches from absorbing force to generating force. The duration of this phase may be critical for athletic performance, as a shorter amortization phase is likely indicative of more efficient coordination of the elastic rebound of tissues, stretch reflex , and voluntary concentric contraction. For example, it is appropriate to cue an athlete to spend as little time as possible at the bottom of their squat stance (the amortization phase) during box jumps.
- Related Topic: Power
- Part of: Stretch-shortening Cycle
- Also Known As: "Time to rebound" and related to "electro-mechanical delay"
Related Courses:
- Power (High-velocity) Training: Introduction
- Lower Body Power Exercises
- Upper Body Power Exercises and Total Body Power Exercises
Frequently Asked Questions (FAQ):
What are the 3 phases of power exercises?
- They are the same phases that occur during exercise; however, they may be referred to by different names.
- Eccentric: quick pre-stretch (loading) phase.
- Amortization: isometric (coupling or time to rebound) phase.
- Concentric: shortening (rebound) phase.
How long should the amortization phase last?
- Ideally, it should be as short as possible.
What affects the duration of the amortization phase?
- Factors include neuromuscular coordination, tendon stiffness, technique, strength levels, and fatigue. Athletes with higher levels of power and skill can generally achieve shorter amortization phases.
Is the amortization phase present in all exercises?
- No. This term is specifically used for activity with a stretch-shortening cycle. The isometric phase of typical resistance training or strength exercise is not referred to as an amortization phase.
How can I train to reduce the amortization phase?
- Plyometric drills, strength training that includes overcoming the transition between eccentric and concentric phases with the aid of the floor or equipment, and improving proprioception and landing mechanics can all help reduce amortization time and improve force transmission.
Examples of Exercises and Their Amortization Phase:
- Box Jump: The amortization phase occurs at the bottom of the quick countermovement before the jump, where the athlete transitions from descending to ascending.
- Depth Jump: After stepping off a box and landing, the amortization phase is the brief moment between landing (eccentric phase) and immediately jumping upward (concentric phase).
- Ice Skaters: During the lateral jump, the amortization phase is the instant between landing on one foot and pushing off laterally to the opposite side.
- Medicine Ball Chest Pass: The amortization phase is the brief pause between the backward movement (eccentric loading) of the arms and the forward thrust (concentric phase) to pass the ball.
- Power Push-Ups: At the lowest point of the push-up, the amortization phase is the transition between lowering the body (eccentric) and explosively pushing up (concentric).
- Power Chop Medicine Ball Smash: The amortization phase occurs at the end of the backswing, transitioning from the upward movement (eccentric) to the downward smash (concentric).
- Squat to Row Sled Pull: The amortization phase occurs at the bottom of the squat, transitioning from the downward movement (eccentric) to the upward pull and row (concentric).