Once you’ve been strength training a while, most “proper” programmes start to work on percentages of your one rep max. The theory is that you are able to do X reps and X sets at X percentage of your 1rm.
Theory is great. Reality is different.
Here’s a few things to think about:
What’s the 1rm based on? An actual lift you’ve done? Or an idea of what you think you can do? Or an extrapolation from what you can do for 3,4 or 5 reps? If it’s from an actual lift, it’s probably fairly accurate – as long as that lift is reasonably recent.
If it’s a “notional” 1rm, or an extrapolation, it’s probably not worth the paper it’s written on. Nothing prepares the body for a 1rm like a 1rm attempt! The higher the weight, the truer this is. Simply because you *should” be able to achieve X weight, doesn’t mean you can. Sometimes you are only a few kilos from the tipping point of a weak body part, or the ability to lift technically well enough to complete it.
For that reason, most online calculators that predict a 1rm from a 3/5/8 rep max are wildly inaccurate. There’s a huge psychological difference, for example, between a 180kg squat, and a 200kg squat. The extra 20kg is, obviously, a lot heavier. It’s also a big psychological jump that can lead your body to flight mode – and shut down your physical ability to lift.
For beginners, percentages are pretty useless. You just don’t know your capabilities well enough, your body hasn’t had enough time to make the smaller, stabilising muscles strong enough to work at higher weights, and you’re asking for injuries.
For more advanced lifters, percentages can be a great *guide* but shouldn’t be treated like the gospel. When you’re playing around with weights at 85/90% of your 1RM things like your nutrition the day before, your sleep in the preceding days, your stress levels in general, your work arrangements – all this is important and WILL impact your ability to perform. An otherwise unnoticeable dip in lifting readiness that doesn’t matter at low weights will be the difference between making, or failing, a lift.
That’s where a really good coach comes in. A really good coach will factor in more than the numbers on the sheet, and will tune your lifts to what is needed that day, rather than what the bit of paper written weeks ago says. Training needs flexibility, and all too often, training to strict percentages just isn’t flexible enough.