Right, leg muscles..mhmm
I've had my share of injuries with them, that kept me limping for a good 6 months. It was tennis related, not really cricket, but I guess its all pretty much the same thing.
Make sure you stretch 5 min before and after you bowl/bat/run/sprint. Very important
Sit on the chair and leave your legs hanging. 'Write' letters in the air-spell your name out- I like this stretch. For your calf muscle (thats what I injured)
Go against a wall and hold your arms against it, your elbows bent. stretch your back leg-first your calf, then your hamstring. switch legs. The position is hard to explain, i'll try and find a good site or something with pics.
Just watch what the international bowlers do on the field before a spell. hold your ankle to your back to stretch your hamstring...sit on the floor with one leg out and the other in and reach your ankles.
Hope this helped, and if you need any more help just PM me or post here. If it gets really stiff and you fail to stretch, even the smallest pressure will cause your muslces to tear, and its really unbearlable pain, imo-and it lasts forever.
If that does happen I suggest physiotherapy (sp)-I had to get it.
Also purchase this product called Bio-Freeze-and apply it to the area where you are stiff. Then firmly run over the muscle in with your two index fingers in a straight motion. Try and get any knots in your muscles straightened out.
Buy Bio-Freeze
Its a really great product. Seriously awesome. Highly suggest.
http://www.amazon.com/Healiohealth-Biofreeze-32-oz-Pump/dp/B0009DRVOG
Most Physiotherapists in your area should carry it.