Swing anchoring

[North]

Hi i have been given a double swing for the kids and i am considering ways of anchoring in the ground. The normal way, i read, is to dig in and create a concrete foundation for every leg of the swing and sink the metal rod before it settles. Is there an easier alternative? this morning i saw in lidl these ground screws:
http://www.alibaba.com/product-gs/51776447/Ground_screws.html
would this or other alternative work? any experience on this field?

 

[Burnerman]

These should work quite well if the ground is very well consolidated, but as swings are always jolting I would expect them to loosen off after a while......concrete would be a better fix.
John