I agree with Busy-Lizzie - there is no other way - just energy and a good sharp spade. As she says, cut it down, but not too short so it's trunk gives you good leverage for the wiggling part of the process, then dig around with a spade until you've dug a trench at least a foot deep all around then start to under-cut with the spade. You'll know when it's time to wiggle.
I dug a very large shrub out of a border at work in my lunch hour (I'm office based - a male colleague thought it would take at least all afternoon and offered to help me 'tomorrow' ).
Cheaper than going to a gym