Eligibility for becoming H.M.
1) 10 years continuous service in aided/govt. high/higher secondary school.
2) An asstt. teacher of physical education must has B.P.Ed./M.P.Ed. But B.P.Ed is not equal of B.T/B.Ed/P.G.B.T.
3) While a B.P.Ed teacher joins as a subject teacher ( not in physical education ), his increment will be stop after 5 years. Increment will be start after the completion of B.Ed or as norms, i.e. that is applicable as usual.
4) A B.P.Ed teacher is an asstt.teacher. I find from your post that you have written if a candidate is illegible having B.Ed (physical education) to appear in the post of H.M. I think if the certificate/degree is equivalent to B.T/B.Ed/P.G.B.T. and he/she able to fulfill other criteria of qualifications, age,experience,marks etc. then he/she may allowed for the selection of the post of an H.M.
I have attached the adv.of this year and you will find from it the other conditions.