Equal force does not mean equal pain. If it did, we'd never punch anyone hard. Technique is the difference.I thought we had done newtons laws on that other thread. If you hard block , then the force,experienced by your arm as the blocker and that by the attacker is the same. Exactly the same. If that equates to equal pain is dependent on which part of the,arm is contacted and on the individuals threshold of pain
or if you have,spent a lot of time banging your arm against something, your pain response will be lower.