Hi.
I do the Ex Sp Science/ Nutrition degree and Im in 3rd year.
Is there a lot of maths? Well kinda, you do have to do a maths subject (with the nutrition you do 12 credit points of it) and some of the subjects do involve maths aswell.
The difference between biomechanics and sports science? This in itself is a sort of dumb question. "Sports science" encompasses a range of disciplines including biomechanics, biochemistry, physiology, anatomy, psychology of sport, rehab, muscle mechanics, nutrition and dealing with the aged and diseased etc.
So there really is no such thing as a "sports scientist" rather people who specialise in an area in of human movement and performance under the area of sport and exercise.
You dont have to deal with athletes nor do you have to have an interest in them to do this degree. Some of this degree deals more so with the diseased population, therefore is perfect for and acts as a pre-medicine degree. Its a great degree thats very challenging and hard work but I love it.