For my course, it's really easy. You could look at the syllabus here:
http://qualifications.pearson.com/en/qualifications/edexcel-gcses/physical-education-2009.htmlBasically, we have to know:
-Reasons for taking part in sport (cultural, health, image, people, socio-economic, resources)
-Benefits of taking part in sport (mental, physical, social)
-Initiatives to get people to take part in sport (government, local, sport participation pyramid)
-Aspects of fitness (health related and skill related)
-Injury and reducing it (warm up, cool down, equipment, balanced competition)
-Other general knowledge fairly easy sport-related stuff that I can't remember of the top of my head
On the biology side of things:
-Diet (7 main parts of a diet, what they all do)
-Cardiovascular system
-Muscular system
-Skeletal system
(all of this and the impact on exercise etc)
It's fairly easy stuff, really. You'll be able to pick it up easily.