Calculating 1RM from Reps

I’m in the third week of Adaption in the 10 week resistance programme and have been increasing my weights steadily. However, the leg-press machine I use has only 100kg on the rack and I reached that with my 4th set last night. I have two Adaption sessions to go before setting my 1RM. So:

  1. What combination of reps/weights should I do for the last two Adaption sets?
    • What relationship do you recommend I use to estimate my 1RM based on reps of lower weights?


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I have found that this works pretty well.

Thanks Rob.

Just got to figure out what changes to make to the reps now.

Just looked at this link and it was pretty accurate for my squat and curl. But my leg press 1RM was way in excess of what this calculator kicked out.

You may struggle to get the full adaptations if your leg press machine is 100kg max I would suggest. Most machine I’ve seen can take 4 times that.

Another option - I track using the Strong app ( and it estimates 1RM based on weight/reps.

If I was on your situation I would do single leg leg presses and MTI’s. Won’t be perfect but it will work.

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Yup, that would save changing gym for a month. Reading up, there are reported benefits to muscle balance and lower back stress.

just done my 1HRM session and have a query on my leg press result. I managed 54kg single leg. However, I can do reps of 10 at that weight, although I can’t push the next weight up, which is 57.5kg. I had the back rets fully extended, which brought my legs to just over 90 degrees, but not quite 100degrees.

Should I base my 1RM on 54kg, or should I use a formula based on the reps I can do at 54kg?

( Squat is at 95kg and leg curl at 73.5kg)


I find this interesting. Your squat and curl are slightly higher than my 1RM but my 1RM (both legs) was 180kg?!