At those altitudes, human beings need bottled oxygen and barely have enough energy to chew their food (much less run, jump and get into fights).
(human beings; need; bottled oxygen; L:At those altitudes) (human beings; barely have; enough energy to chew their food (much less run, jump and get into fights)
human beings human beings
need barely have
bottled oxygen L:At those altitudes
enough energy to chew their food (much less run, jump and get into fights