4 Types of Muscle Contractions
Weight Lifting Tempo
Tempo is the program design variable referencing the speed of movement for each repetition of an exercise. A repetition is comprised of 4 types of muscle contractions.
4 types of muscle contractions
- Isometric: The muscle is developing tension and contracting but no joint movement occurs. This is your starting position.
- Eccentric: The muscle is lengthening, yielding to the force of the applied resistance while storing mechanical (potential) energy which, is then, released during the concentric phase of muscle action. Depending on the skill level and training goal of a client, this phase can last from a very brief instant to a number of seconds.
- Second Isometric (Transition): This is the transition from lengthening (storing potential energy) to shortening (the release of kinetic energy). The muscle is developing tension and contracting but no joint movement occurs. The technical term for this action is the amortisation phase and it can last from milliseconds during an explosive exercise to an extended period of time for an isometric exercise.
- Concentric: The muscle is shortening, releasing the mechanical (kinetic) energy to generate the force required to overcome an applied resistance. This phase can last from a brief instant during an explosive exercise to a period of 15 seconds or longer during a slow-tempo exercise.
THE VIDEO: Types of Muscle Contractions – Weight Lifting Tempo
The importance of tempo and muscle contractions
A big consideration of tempo is time under tension (TUT) which, is the length of time that muscle fibres are under mechanical tension from a resistance-training exercise. Along with intensity, TUT is critical for creating the desired stimulus for increasing muscle definition or size or eliciting as much force as possible.
In most strength training programs, weight lifting tempo is expressed as isometric-to-eccentric-to-isometric-to-concentric which, means that a 1:3:1:1 tempo = 1 sec isometric: 3 sec eccentric: 1 sec isometric: 1 sec concentric. While TUT in the eccentric phase provides a strong stimulus for muscle growth, the overall goal of the training program, the amount of intensity used and the client’s experience, dictate the tempo of an exercise.
Use slow tempo for muscle size and strength endurance
If your goal is hypertrophy or increasing muscle size and strength endurance then, focusing on slow reps to build muscle is a good place to start. When you do a slow rep tempo workout, your muscles experience a greater time under tension than they would, if you were doing fast reps.
Keeping a muscle under tension for an extended period of time will place mechanical strain on muscle fibres, triggering the metabolic stimulus necessary to signal the mechanisms responsible for repairing structural damage to existing fibres and laying down the foundation for new muscle cells. In addition, taking a slower approach to strength training while using lighter weights is a safer approach for beginners. Slowing the tempo down allows you to focus on form and make sure you’re doing the move correctly.
Use fast tempo for strength and power
If your fitness goals involve strength and power then, using a faster tempo may be more beneficial. Maximum strength training with heavier loads (85-100% 1-RM) generally requires a faster, more explosive tempo to create a mechanical stimulus and recruit all available muscle motor units. Even though the weight might not be traveling that fast, the lifter is pushing as hard as possible to generate momentum.
While faster reps are generally linked to more explosive movements that result in power, training with this tempo can also produce gains in muscle size.
Even though training tempos serve a specific purpose, you can’t go wrong incorporating slow and fast reps into your overall workout. Using a fairly wide range of repetition tempos is ideal, if the primary goal is to maximise muscle growth. The bottom line is that you will benefit from strength training with both tempos.