When you’re training there are times when it is appropriate to lock out for a second at the top of a movement before proceeding into the next rep.
However, if you’re really trying to maintain tension on a muscle you might want to try maintaining constant tension next time you train instead.
Rather than stopping to rest at the top or bottom position of a movement, execute the whole set with a controlled tempo and absolutely no stopping or locking out during the set.
This method will inherently make you want to speed up your tempo to get away from the fierce burning in your muscles that will ensue. Don’t to that. Stay with the nice, slow negatives and keep the tension on the muscles for the whole movement.
You’ll likely need to reduce your weights as this method of training can be humbling, but it can also serve as a powerful stimulus.