In about 1988, we installed a tie-down point at Honington in preparation for a 'Bolthole' for a Phantom squadron. It had to be tested, of course, and that was achieved by tying-down a Phantom, with the CO of the squadron in the cockpit IIRC, and running it at full chat, then with full reheat - to see if the tie-down held. It did. I noticed, though, that just before 'giving it welly', the pilot extended the nose leg - the gentle rising of the nose was quite elegant to watch. No idea why it was extended and as he taxied off afterwards, I never had the chance to ask.
I was standing a few feet from the stbd wing whilst all this happened. Even with ear defenders, a most impressive sound and much vibration through my DMS shoes. When self and PSA chaps wandered on to the concrete to check the tie-downs - it was still flippin' hot and started to melt the rubber on my shoes - so, quick scarper on to the grass!