Time Under Tension
Definition: The total duration a muscle is under strain during a set. Slowing down the eccentric (lowering) phase to 3-4 seconds can increase muscle activation and hypertrophy stimulus.
Why It Matters
Understanding time under tension is essential for making real progress in your fitness journey. Without this knowledge, you risk spinning your wheels — training hard but not seeing the results you deserve.
Callio automatically tracks and applies time under tension principles to your training program, so you don't need to be an exercise scientist to benefit from evidence-based programming.