Back to serious riding, got cramp!

[Fools Motto]

For weeks, if not months, all I've done is gentle hacking, either on mine, or some polo ponies. That then stopped and I did no riding what so ever for at least 3 weeks over December.
Just started a new job, which involves schooling some (very) large horses - not what I'm used to!
I knew I'd be a bit puffed, bit sweaty and very rusty. But 2 weeks in, I ache - still and when home in the evenings, sit down, can't move for cramp in my legs. Mainly back thighs, left leg worse. I had cramp before when pregnant (not pregnant!), and it was due to diet - or baby 'stealing'! I had hoped I'd be over this now, and cracking on, but here I am, left leg cramped up.
What can I do/should I do to help?

 

[flirtygerty]

Research exercises for core muscles and do them, I have a dodgy hip on one leg and a damaged knee on the other, so I can only ride for a limited time, I get off and lead, but then they are not my job. I also sit on an exercise ball which helps my hip, salt is supposed to help with cramp, there is a thread on here about Tumeric, that might also help

 

[showpony]

Magnesium oak is a great natural supplement which helps preventing cramps... That or a large bottle.of tonic water ( the quinine in it is good for cramps aswell)

 

[merry neddy man]

I used to suffer very bad leg cramps every evening, went to docs one quinine tablet a day and not had any cramp for 5 yrs ,and its cheaper than tonic water .