Tempo / Time Per Repetition

Tempo is the time spent on each repetition, applied separately to the concentric (lifting) and eccentric (lowering) phases. The COMBO program prescribes 1.5 seconds for concentric actions (positive) and 2.0 seconds for eccentric actions (negative) per repetition.

With safety as the number-one concern, resistance-training exercises should be performed in a slow, controlled manner (Westcott, 1987). Fast movements place considerable stress on the muscles, connective tissue, and joint structures and should be avoided. Many people prefer fast resistance training because they can use heavier loads, but it is momentum rather than muscle that permits this. Fast strength training is more dangerous and less effective than slow training. Slow resistance training is characterized by more muscle tension, more muscle force, and more muscle-fiber recruitment, all of which enhance strength development.

A good guideline for movement speed is 60 degrees of movement per second. Because many exercises traverse about 120 degrees, this corresponds to about 2 seconds for each phase of the lifting movement. A momentary pause in the fully contracted position is advocated, followed by a controlled lowering movement. The lowering (eccentric) movement should be at least as long as the lifting (concentric) movement, because muscles produce more force in eccentric than in concentric action.

Slow technique example: a fast-paced 1-second-up / 1-second-down cadence requires only 20 seconds of continuous muscle tension for 10 reps, whereas a slow-paced 2-second-up / 4-second-down cadence requires 60 seconds of continuous tension for 10 reps. Given the same weight load, both accomplish the same work, but the slow technique demands much more muscle effort. There is an inverse relationship between movement speed and muscle force: maximum force produced at 60°/second is greater than at 120°/second.

Other program tempo prescriptions:

• Power Program: 1 to 1.5 s concentric, 1.5 s eccentric.
• Endurance Program: 2.0 s concentric, 3.0 s eccentric.

• COMBO program: 1.5 s concentric, 2.0 s eccentric per rep.
• Guideline movement speed: 60 degrees per second (~2 s per phase over ~120°).
• Slow training = more muscle tension, force, and fiber recruitment.
• Eccentric (lowering) should be at least as long as concentric (lifting); muscles are stronger eccentrically.
• Inverse relationship between movement speed and muscle force.
• Power Program tempo: 1-1.5 s up / 1.5 s down. Endurance Program tempo: 2.0 s up / 3.0 s down.
• 2026 update: for strength/power, explosive concentric intent beats a slow concentric (see verification_note); hypertrophy is largely tempo-agnostic. The safety case for controlled, non-ballistic movement is unaffected.

• repetition — the phases (concentric/mid-range/eccentric) tempo applies to.
• muscle-action-terminology — concentric vs eccentric force differences.
• momentum-injury-risk — fast tempo relies on dangerous momentum.
• intensity — exercise speed affects intensity.
• movement-speed — the principle this variable implements; carries the same 2026 currency update on slow-vs-explosive concentric tempo.