Time under tension can have a huge role in your muscular development.
You see most guys in the guy just moving the weights as fast as possible. This isn't how it's done. Control the weight, and you'll control how your body looks and performs.
Here's how to read these numbers:
First Number: Eccentric. This is lowering the weight.
Second Number: Pause between eccentric and concentric.
Third Number: Concentric. This is applyig force to raise the weight against gravity.
Fourth Number: Pause between concentric and eccentric.
For example, a 3010 tempo on the bench press would go like so: Lower the weight to your chest for 3 seconds. Press the weight up for 1 second. That's 1 rep.
Another example, a 30X0 tempo on the overhead press would be: press the weight up explosively as quickly as possible (X), lower the weight under control for 3 seconds. That's 1 rep.
Now, these tempos aren't set in stone (or dragon glass), but they are good general rules to follow to ensure that you are consistent with controlling the weight.
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