A Body by Science app for one slow set per exercise.
Dr. Doug McGuff and John Little's Body by Science describes a short machine workout, the Big Five, done as one slow set per exercise with long recovery between sessions. Intense Fit is an independent app that gives that style of training a voice cadence, a set timer and an honest log.
The Big Five, and Intense Fit's default session
The book's Big Five are seated row, chest press, pulldown, overhead press and leg press. Intense Fit's default Full Body session uses those five machines plus a leg extension done right before the leg press, in this order:
- Seated row — mid-back and rear shoulders.
- Chest press — chest, front shoulders, triceps.
- Pulldown — lats, biceps.
- Overhead press — shoulders, triceps.
- Leg extension — quads, as a pre-exhaust.
- Leg press — quads, hamstrings, glutes.
You can swap an exercise when your gym lacks a machine.
What the app tracks
- Time under load — a timer for each set, with spoken cadence cues and beeps to help you keep a slow, steady tempo.
- Load and reps — logged per exercise so you can compare with last session. Reps can be entered by hand.
- Optional camera estimates — with the camera on, the app tries to estimate reps and cadence. These are estimates; camera angle and machine occlusion affect them, and with the camera off reps are simply marked "not captured".
- Next-load suggestions — based on your logged load and time under load. You stay in charge of the weight.
- Recovery check-in — a short sleep/energy/soreness check plus time since your last session, used to suggest whether today is a good day to train.
The app does not detect true muscular failure. How hard you push, and when a set ends, is your decision. It is not medical advice or a rehabilitation programme.
Common questions
Is this the official Body by Science app?
No. Intense Fit is an independent app. It is not affiliated with, or endorsed by, Dr. Doug McGuff, John Little or the publishers of Body by Science.
How is it different from HIIT or a general gym log?
HIIT is interval conditioning. This is slow-cadence resistance training on machines. General logs like Strong or Hevy are built around sets, rest timers and weekly volume; Intense Fit is built around one timed set per exercise, its cadence and its load. See the time-under-load tracker for what each set records.
Where can I use it?
Intense Fit runs in the browser on your phone at intensefit.co/app. A native Android app is in closed beta; you can request Android beta access.
How is this different from Heavy Duty?
Mike Mentzer's Heavy Duty is a separate system with its own routines. Read Intense Fit for Heavy Duty-style training for the differences.
Learn the method
The tracker is free. A typical session in this protocol takes around twelve minutes.
Start free — forever →