Insights, not instructions.
Most fitness apps hand you orders. Heft shows what your training did, with the numbers behind it, and leaves the next call to you.
Free to start. No ads, no account required.
You’re told:
Rest 60 seconds between sets.Heft shows: Bench press at 80 kg- 1:00 rest
- −2.3 reps
- 3:00 rest
- −0.3 reps
You’re told:
Train first thing in the morning.Heft shows: Time of day+6 % Your lifts are stronger in the evening.
You’re told:
Great workout! Keep it up!Heft shows: Session score82- Plan 31/35
- Effort 20/30
- Progress 19/20
- Balance 12/15
An order tells you what to do. It can’t tell you why.
“Rest 60 seconds.” “Train legs.” “Great job.” An instruction is quick to follow and impossible to check. When it stops working, you have nothing to look at.
An insight gives you the material instead: what you lifted, how it compares with last time, and how the number was worked out. With that in front of you, the next decision takes seconds, and it fits the day you’re actually having.
It matters because people respond differently to the same training. When 585 adults followed one 12-week arm program, their strength and muscle gains varied widely (Hubal and colleagues, 2005). Your own log is the best evidence you have.
Use your workout log to decide what comes nextWhat did your last weeks actually show?
After a few workouts, your coach writes a review. It isn’t a pep talk. It’s a handful of findings, each one drawn from the sets you logged.
- Heft shows
- Which lifts beat the same workout a month ago. The time of day you lift best. What a short rest costs your bench, in reps.
- You decide
- Whether a finding fits your life. Every review ends with one move, and you answer “Spot on” or “Not for me”.
The first finding of every review is free. Premium opens them all.
Why was that an 82?
After your last set you get one number from 0 to 100. Tap it and it comes apart.
- Heft shows
- The points each part earned: 16 of 18 planned sets, 7 of 15 working sets close to failure, a new best on bench press, triceps left short.
- You decide
- Whether a low score was a bad day or just a short one, and what the next session is for.
What is this weight good for?
During a workout, every exercise shows what each load means for you right now.
- Heft shows
- 6–8 reps at 90 kg, which builds muscle. 11–13 at 80 kg. 1–3 at 100 kg. Next to it, your records: 111 kg estimated max, up 25 kg in 30 days.
- You decide
- What goes on the bar today.
Rep ranges are free. Records and trends are Premium.
How many sets are enough?
Each muscle group has a weekly set goal, and the goal shows where it comes from.
- Heft shows
- 20 hard sets for chest against a goal of 12. Tap the footnote and you get the growth curve from Schoenfeld and colleagues (2017, 15 studies), with your week marked on it.
- You decide
- Whether to keep the goal or set your own.
The muscle overview is free. Detail per muscle group is Premium.
Where do you stand?
Your lifts sit on one ladder from Bronze to Legend, measured against strength standards for your body weight.
- Heft shows
- Gold 3, up from Gold 1 since November, and 80% of the way to Platinum 1. The chart shows every step that got you there.
- You decide
- Which lift deserves the work, and which is already ahead.
Your overall level is free. Levels per muscle group are Premium.
Every number shows its work.
A number you can’t check is just another instruction. So Heft publishes how each one is made.
How the score and levels are calculated- Tap any session score to see what each of the four parts earned.
- Weekly set goals name the studies they come from.
- Strength levels use standards for 362 exercises, and the thresholds are public.
- One-rep-max estimates stay conservative on high-rep sets.
When Heft does suggest something, you see why.
Heft isn’t silent. You can start from one of 81 free workouts, and a coach review can offer a step, like a longer rest timer for your bench. The step sits under the finding it comes from, so you can check it against your log.
Nothing is locked. Change the weight, swap the exercise, drop a set. It’s your workout.
Browse the free workoutsQuestions about insights
What does “insights, not instructions” mean?
Heft shows what happened in your training and how each number was calculated: coach reviews, the session score, rep ranges per weight, weekly sets per muscle and strength levels. It doesn’t lock you into a prescribed program. You read the numbers and decide the next session.
What is a coach review?
A short story about your recent training, written from your own log once you’ve trained at least twice. Each finding is one observation with its numbers, for example which lifts beat the same workout a month ago or what a short rest costs you in reps. The first finding is free; Premium opens them all.
Does Heft tell me what to do in the gym?
Only if you want it to. You can follow one of the built-in workouts or your own plan. Suggestions come with the numbers behind them, and you can change any weight, rep target or exercise.
How is the session score calculated?
It’s a rating from 0 to 100 built from four parts: plan (35%), effort (30%), progress (20%) and balance (15%). Each workout is measured against your own plan and your previous sessions. Tap the score in the app to see what each part earned.
Where do the weekly set goals come from?
From research on training volume and muscle growth. The default is 12 hard sets a week for large muscle groups and 6 for smaller ones, where a hard set ends within two reps of failure. The app shows the dose-response curve from Schoenfeld and colleagues (2017), and you can set your own goals.
Which insights are free?
Logging, the session score, rep ranges per weight, the muscle overview, your overall strength level and the first finding of every coach review are free. Premium adds records and trends, detail per muscle group and full coach reviews, and starts with a 7-day free trial.
See what your next workout tells you.
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