Normative ratio between squat and lunge?

Question

I squat and deadlift with a barbell regularly. I know how much I can lift with variants of those exercises on a given day. I'd like to use that knowledge to better understand how much I should expect to lift with a weighted lunge.

What is the normative ratio between a lifter's squat and their lunge?

We know these relationships, in broad strokes and with some caveats, between other lifts. The front squat and back squat, the squat and the deadlift, the deadlift and the power clean, and so on all have known relationships consisting of a range of ratios. For instance, a power clean between 40 and 60 percent of one's deadlift is to be expected, and most people's front squat is generally about 80% of their back squat. So: what lunge is to be expected if one can squat X?

Any type of loaded squat and any type of loaded lunge is acceptable, but please be specific: e.g. "barbell back squat to forward-stepping lunge with a barbell across the shoulders" or "barbell front squat to rearward-stepping lunge with dumbbells in the hands". Anecdotes welcome but data welcome more.

Answer 1

Eric from Power Dojo states:

The ratio that I give in my Ultimate MMA Strength and Conditioning Program is that you should be able to perform a Reverse barbell lunge at a minimum of 1/2 of your max Back squat, but I’d prefer you get that up to 2/3 your max Back squat. [...] basically you should be able to do a Reverse Barbell Lunge with at least your bodyweight for 3 reps per side.

This makes sense, as most unilateral exercises can be done at around half of their bilateral counterparts.

He also makes a point for when the lunge is below this ratio:

[...] the unilateral Lunge is weak – showing that the hip and/or core muscles are weak compared to the quads.

Referenced article