So instead of doing the bench press, where you have the vertical tension of the press, change to a squeeze press, where the two weights are brought together at the chest.
Press the parallel dumbbells together as hard as you can (the horizontal tension), and then as you keep this horizontal tension firm, press the weight.
Use a 4-7 second count on the EC, but don’t stop with the the EC, pause for one second at the bottom, press as fast as possible, then pause and squeeze the muscle at the top for one second, and repeat.
Usually we increase the tension in the muscle by adding more weight, but that isn’t an option here.
If 70 lbs isn’t that light, you can add more time to the eccentric contraction (EC), that is, the way down.
With light weights you can’t do this, your rep count will be too high to experience the tension and reach failure within reps that are typically designed for hypertrophy.
So what you have to do is fail as quickly as you possibly can.
You’ll find that you’ll fail much quicker with much lighter weights if you combine this added tension with the variations in tempo that you’re using.
Does hypertrophy have to be confined to the 8-12 rep range? Hypertrophy is building muscle, so whichever exercises or rep counts or sets help you build the most muscle can be coined as hypertrophy.