There's the belief that deadlifting from a big deficit (like 4 inches or so) will improve your strength off the floor in a standard deadlift. It won't. It's too dissimilar to transfer over to your conventional deadlift. But with a very small deficit – my go-to is standing on a standard 45-pound plate – the positioning is pretty much the same, but it makes the beginning of the lift slightly harder. .
• Make the start of the lift slightly more difficult.
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• Keep movement patterning similar.
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• Get a high degree of transfer to the lift itself.
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Deadlift monster, Chris Duffin, relayed this same principle to me a while back. He'd been deadlifting standing on mats for months. We're talking maybe a half-inch deficit. Then one weekend he deadlifted at another location, where there were no mats. He kept wondering why the weights felt so much lighter than usual. Then it dawned on him that he was pulling from the floor, and what a massive difference it made (way easier from the floor after standing on the mats). Once I figured this out I never deadlifted from the floor again in training. It was always from a small deficit. The only time I'd pull from the floor would be on meet day.
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Let me repeat that in case words are hard. I trained from a small deficit the entire training cycle, and the only time I pulled from the floor was on the day of the competition.