Eccentric (Negative) Muscle Action
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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.
Detail
An eccentric action (also called negative action) is a dynamic action in which the active muscle is forcibly lengthened as it resists the external resistance — one in which a force external to the muscle overcomes the muscle force and the ends of the muscle are drawn further apart. In a repetition it is the eccentric phase: the lowering phase of movement, a lengthening against load.
Key properties:
- It increases muscle length (the "negative" half of a dynamic exercise).
- It is the primary instigator of delayed-onset muscle soreness (DOMS), and is associated with the connective tissue damage hypothesis of soreness (irritation or damage of connective tissue from exercise using eccentric contractions).
- The muscle produces more force in lowering (eccentric) action than in lifting (concentric) action — about 40% stronger than the concentric phase — so this phase should be accentuated and needs to be emphasized for optimal hypertrophy.
- It should be performed in a deliberate fashion; the lowering movement should be at least as long as the lifting movement. Typical prescribed tempos run about 2 to 3 seconds for the eccentric (negative) phase.
- Using a combination of concentric and eccentric actions, rather than only concentric actions, produces superior gains in strength.
Note on terminology: the source insists "There is no such thing as 'Eccentric Contractions'" — a lengthening muscle is not strictly contracting.
Key facts
- Eccentric = negative action; external force overcomes muscle, ends drawn apart, muscle lengthens.
- The lowering phase of a repetition; increases muscle length.
- ~40% stronger than concentric; should be accentuated; key for hypertrophy.
- Primary instigator of DOMS; linked to connective tissue damage.
- Combining concentric + eccentric beats concentric-only for strength gains.
Connections
- Concentric (Positive) Muscle Action — the weaker lifting counterpart.
- Isometric (Static) Muscle Action — the static action.
- "Muscle Action" vs. "Contraction" — The Terminology Argument — "action" vs. "contraction"; no "eccentric contractions."
- Muscle Soreness — Acute vs. DOMS — acute vs. delayed soreness.
- Three Hypotheses of Muscle Soreness — connective tissue damage hypothesis tied to eccentric work.
- Tempo / Time Per Repetition — repetition timing of the eccentric phase.
- Resistance Training Guidelines for Safe, Effective, Efficient Training (ACSM) — the "control the eccentric as well as the concentric" guideline.
Sources
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