How close to failure natural lifters should train for muscle: what the failure meta-analyses show, how to use RIR and RPE, and where failure fits in your week.

How the builder works

Pick a starting block

Open a starter program or begin blank. Every week, day and exercise stays editable.

Write the prescription

Set exercises, variations, sets, reps, load, percentage, RPE and rest for each row.

Share a short link

Share saves a snapshot and returns a short link. Anyone can open and adapt their own copy.

Common questions

All questions

Is naturalbodybuild.ing free?

Yes. The builder, the starter programs and sharing are free, with no account. naturalbodybuild.ing is one of the free tools by iTrain.

How long should a hypertrophy program be?

Most starter blocks here run 4 weeks with a clear change each week. Research on resistance training supports 2 or more sessions a week per muscle group; see the 2016 frequency meta-analysis and the ACSM physical activity guidelines.

How do I share a program?

Press Share in the builder. It saves a snapshot and returns a short link. Anyone with the link can open the program and save their own version.