Power
Power
The Three Phases of a Plyometric (Eccentric, Amortization, Concentric)
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DefinitionA short reference note, not a full lesson.
Definition
Every plyometric has three phases — a loading stretch (eccentric), a brief pause (amortization), and an explosive push (concentric); the shorter the middle phase, the more powerful the result.
Detail
A plyometric repetition is broken into three sequential phases:
- Eccentric (loading / pre-stretch) phase — the muscle-tendon unit lengthens under tension, e.g., the dip/landing of a jump. Elastic strain energy is stored and the muscle spindles are activated, setting up the stretch reflex.
- Amortization (transition / coupling) phase — the time between the end of the eccentric phase and the start of the concentric phase. This is the most important phase: it must be as short as possible. A prolonged amortization lets stored elastic energy dissipate as heat and reduces the stretch-reflex contribution, turning the movement into an ordinary concentric action.
- Concentric (unloading / push-off) phase — the muscle shortens explosively, releasing stored elastic energy plus the reflex-augmented contraction, producing more force than a concentric action alone.
Together these phases are the applied form of the stretch-shortening cycle. Coaching cues emphasize minimizing ground-contact (amortization) time — "stiff ankles," "off the ground fast," "quiet, quick feet" — for reactive/fast plyometrics.
Key facts
- Three phases: eccentric (load/stretch) → amortization (transition) → concentric (push).
- Amortization is the key, time-sensitive phase; keep it as short as possible.
- A long amortization dissipates stored elastic energy and weakens the stretch reflex.
- The phases are the practical expression of the stretch-shortening cycle.
Connections
- Stretch-Shortening Cycle (SSC) — the three phases enact the SSC.
- Plyometrics (Definition) — phases define the plyometric rep.
- Reactive Strength — short amortization = high reactive strength.
- Eccentric (Negative) Muscle Action — the loading phase.
- Concentric (Positive) Muscle Action — the explosive push-off phase.
Sources
Cited in text — not yet linked
Established exercise-science consensus; NSCA Essentials of Strength Training & Conditioning. Pages: (general consensus).
Keep this lesson, or ask how it applies to you.
Educational content only — not medical advice. Always consult a qualified professional for individualized guidance, especially around injury, pregnancy, or medical conditions.
Explore related topics
The Three Phases of a Plyometric (Eccentric, Amortization, Concentric)
Concentric (Positive…Eccentric (Negative)…Plyometrics (Definit…Reactive StrengthStretch-Shortening C…Atlas Connections
Concentric (Positive) Muscle Action
The lifting phase — a dynamic action where the whole muscle shortens, its ends draw closer together, and joint movement occurs.Eccentric (Negative) Muscle Action
The lowering phase — a dynamic action where an external force overcomes the muscle and forcibly lengthens it; the strongest action and the chief cause of DOMS.Plyometrics (Definition)Closely related
Quick, powerful movements that use a rapid eccentric pre-stretch immediately followed by an explosive concentric action — training the stretch-shortening cycle to produce more power.Reactive StrengthClosely related
The ability to switch quickly from absorbing force (eccentric) to producing force (concentric) — how well an athlete uses the stretch-shortening cycle.Stretch-Shortening Cycle (SSC)Closely related
A rapid eccentric (stretch) immediately followed by a concentric (shortening) action produces more force than the concentric action alone — the engine behind plyometrics.