Repetition

A repetition is a single completed movement of an exercise, carried out from the starting position through the entire movement and then back to the starting position (Fleck & Kraemer, 1997). Each repetition has three phases:

• Concentric phase — the muscle shortens against a load. The lifter should refrain from using momentum (which reduces muscular loading), move in a deliberate and controlled manner, and avoid ballistic-type movements, which compromise safety and effectiveness.
• Mid-range position — the position of full muscle contraction. A brief pause here eliminates the effects of momentum.
• Eccentric phase — the lowering phase of the movement (the muscle lengthens against the load). This phase needs to be emphasized for optimal muscular hypertrophy. The eccentric phase is about 40% stronger than the concentric phase, so it should be accentuated.

A useful mnemonic (R-E-P-S):

• R: Refrain from using momentum during the concentric phase.
• E: Emphasize the mid-range position.
• P: Perform the eccentric phase in a deliberate fashion.
• S: Stimulate your muscles throughout the range of motion.

• A repetition = one full movement out and back to the start.
• Three phases: concentric (shortening), mid-range (full contraction), eccentric (lengthening/lowering).
• Eccentric phase is ~40% stronger than the concentric phase.
• Emphasize the eccentric phase for hypertrophy; avoid momentum and ballistic movements.

• repetition-maximum — reps are counted toward a repetition maximum (RM).
• tempo — time spent in each phase per repetition.
• muscle-action-terminology — concentric/eccentric/isometric muscle actions.