Scutum and Pilum Question

[abou]

The reason why I say there would be more strain on the forearm is because I would imagine the shield would be held with the palm facing down rather than up. When you lift weights and grasp the bar from above with palms down that works the forearms, which is different from what is normally done with the palm up. Now, if a pilum were held in the shield-hand that would leave it along the horizontal axis and, as Elthore stated, difficult because of the curve of the scutum - if possible at all. Hence, my confusion to this.

I've looked around on reenacting websites, but haven't found much to answer my question.

Pilum are held ONTO the shield by clips aren't they?

Nothing I have read has made mention of clips except in the case of plumbatae. Personally, I don't think clips could hold the heavy pilum in place.