Lifting the shield and blocking a weapon are lifting strength whether due to the weight of either objects yeah. Technically catching a strong punch with your hand would be lifting strength in RL physics are taken into account, but when it comes to common practices on VSBW, it would be considered
Calc Stacking. So we avoid trying to calculate force by dividing joules/AP value by distance. Though, blocking attacks from giant characters or giant weapons are something we could treat as lifting strength.