%A ???? ?????? %A ???????? ????????? %A ???????? ?????????? %A ???? ?????? %A ?????????? ????????? %A ???????? ????????? %A ???????? ????????? %J Pedagogy of Physical Culture and Sports %T Effect of swimming with the use of aqua fitness elements and interval hypoxic training on the physical fitness of boys aged 11-12 years %D 2018 %L zu236066