I suppose one can participate inactively, but the "active" merely emphasizes the fact that you did something, or a lot.

"have been" is correct if you're still a student.

I (have) participated actively in a range of extracurricular activities throughout my entire school career...

thanks dude (good name btw)

i am not a student anymore (that is high school, i am at uni now), therefore i rearranged the sentence structure to take the "have been" out...
yet i dont understand how this verb tense suggests that i am still a student..?

i have also been thinking to maybe substitute the word "actively" with "eagerly"...that would give it more of a positive touch...?

In this context the present perfect suggests you started something in the past you haven't finished yet.
Past tense: You participated in a lot of activities at school, but now you don't do so anymore as you've finished school.