Methodology
Tempo and Time Under Tension, Does It Matter?
Francesco Zen, founder of ZTraining · Last updated June 20, 2026
A worked example
A worked example A 100lbs squat done for 10 regular reps is one thing. Take the same 100lbs and add a 3-second concentric phase for those same 10 reps, that's 30 seconds of added concentric tension per set. Across 3 sets, that's an extra 90 seconds of real concentric time under tension. No weight was added, but the work just got noticeably harder.
Who this matters most for
Time under tension is uniquely relevant for intermediate lifters working to become advanced. It's a genuine lever to increase difficulty and drive muscle growth without needing to add load, which matters most exactly at the stage where adding weight every week stops being realistic.
Related: Progressive overload, explained simply · Does the mind-muscle connection matter?
Francesco Zen is the founder of ZTraining and ZLIFE, with 18 years of coaching experience working with executives across the UK, US, and UAE. He built Mr Z, an AI coach trained on his methodology to bring the same approach to a wider audience.