Eccentric Contraction
Eccentric Muscle Contraction: A type of muscle contraction in which, despite activation of motor units and the production of force, the external resistance forces the muscle to lengthen. This occurs when the force produced by the muscle is less than the external resistance. Functionally, eccentric contractions can be thought of as actions that slow down or decelerate the body or a body segment, helping us to "absorb" resistance.
- Etymology: The word is formed from two parts: "ecc" (out of) and "centric" (center). Lengthening could be considered as coming "out of" a shortened position or, perhaps, out of the center.
Key Characteristics:
- Muscle fibers lengthen while generating tension.
- Decelerates or slows down the progress of an external resistance/load (e.g., slowing down a barbell as it descends toward the floor).
Contraction Types:
- Shortening Contraction: Concentric contraction
- Same-length Contraction: Isometric contraction
- Lengthening Contraction: Eccentric contraction
Additional Resources:
- Related Course: Lesson 3: Joint Actions
- Related Course: Acute Variables: Repetition Tempo
- Related Article: The Best Weight Lifting Tempo: Maximum Velocity Concentrics
Examples of Concentric Contractions:
Note: During an eccentric contraction, the same muscles are active as during the concentric phase; however, external resistance causes the opposite joint actions to occur.
- Biceps Curl (Downward Phase): The biceps brachii contract eccentrically and lengthen to slow the weight down as the elbow extends.
- Squat (Downward Phase): The gluteus maximus and quadriceps contract eccentrically and lengthen to slow the weight down as the hips and knees flex.
- Push-Up (Downward Phase): The pectoralis major and triceps brachii contract eccentrically and lengthen to slow the body down as the shoulders horizontally abduct and the elbows flex.
- Dumbell Chest Press (Downward Phase): The pectoralis major and triceps brachii contract eccentrically and lengthen to slow the weight down as the shoulders horizontally abduct and the elbows flex.
- Seated Row (Forward Phase): The latissimus dorsi and biceps brachii contract eccentrically and lengthen to slow the resistance down as the shoulders flex, the elbows extend, and the handle moves further from the body.
- Lat Pull Downs (Upward Phase): The latissimus dorsi and biceps brachii contract eccentrically and lengthen to slow the resistance down as the shoulders abduct, the elbows extend, and the bar moves further from the body.
- Reverse Flye/Horizontal Abduction (Forward Phase): The posterior deltoids contract eccentrically and lengthen to slow the resistance down as the shoulders horizontally adduct and the resistance comes forward.
- Jumping (Downward Phase): The gluteus maximus and quadriceps contract eccentrically and lengthen to slow the body down during landing as the hips and knees flex.
- Kettle Bell Swing (Downward Phase): The gluteus maximus and quadriceps contract eccentrically and lengthen to slow the weight down as the hips and knees flex, and the anterior deltoid contract eccentrically and lengthen to slow the weight down as the shoulder extends.
An Example of "Eccentric Contraction" Used in Practice:
- Cited from the course Acute Variables: Repetition Tempo , and the article The Best Weight Lifting Tempo: Maximum Velocity Concentrics .
Tempo Notation and Recommendations
Repetition (rep) tempos are generally notated in the following format "(3:1:2)". The numbers are seconds (sec.) unless otherwise indicated. Each number corresponds to a phase of contraction in the following order: "eccentric: isometric: concentric." For Example, a pull-up with a 4:1:2 tempo would be performed with the following cadence: 2 seconds on the way up, 1-second hold at the top, and 4 seconds on the way down.
- Slow Tempo: 5 sec. or more per rep (e.g. 3:1:2)
- Moderate Tempo: 2 - 4 sec. per rep (e.g. 2:1:1)
- Fast tempo: 2 sec. or less per rep (e.g. 1:0:1)
- Maximum Voluntary Concentric Tempo (MaxV): A maximum velocity concentric contraction that does not include a quick pre-stretch, the intent to throw an object, or the intent to leave the ground (e.g. the fastest concentric contraction that can be achieved during a bench press or squat). These tempos are as fast as the load can be lifted, but are distinct from the explosive tempos used during power exercises.
- Explosive: A maximal velocity rep that includes a quick pre-stretch, shortest possible amortization phase (isometric), and the intent to release an object or leave the ground during the concentric contraction.
- +: indicates "or longer"
Brookbush Institute's Evidence-based Tempo Recommendations:
- Activation Exercises: 2-4: 2-4: MaxV or explosive
- Endurance: 2+: 0-2: MaxV or longer
- Hypertrophy: 2+: 0-2: MaxV or longer
- Functional Strength: 2+: 0-2: MaxV
- Max Strength: lifter's preference: 0: MaxV (load)
- Power: Explosive: 0: Explosive (speed) - Explosive tempos include a quick pre-stretch, the shortest amortization phase possible, and a concentric contraction with the intent to release an object or leave the ground.