I have attended enough UP pep rallies and other UP events to notice that not all of us sing UP Naming Mahal the same way.
When I was a freshie, our block handler told us that the right way to sing it was to raise your LEFT fist in the air, and strongly pump your fist only at Mabuhay ang pag-asa ng bayan, mabuhay ang pag-asa ng bayan. Why the left? The explanation given was because the UP has always been left-leaning, and to signify our non-alignment with the establishment (*sigh* youthful petulance? idealism? -- that's another matter). One professor (I forgot his name) said that the UP rally scene in the movie Dekada ’70 is not entirely correct because the rallyists lifted their right fists while singing the UP Anthem. You only pump your fist at the last two lines to drive home the pag-asa ng bayan point. My high-school classmates who went to UPLB and my batch-mates at the Institute were also taught the same thing.
But judging from the past UP events, it appears that there are no steadfast rules on how to sing UP Naming Mahal. Or perhaps, the symbolism that formerly accompanied the UP Naming Mahal are totally lost on the succeeding generations; if it’s so, then it is just sad. Former UP tibaks still have a lot to teach us young ’uns. But it could be that the variations are as diverse as the members of the UP Community itself. Whatever the case, I will continue to sing it the way I was taught, left fist in the air, conviction in my voice, especially in the part Mabuhay ang pag-asa ng bayan, Mabuhay ang pag-asa ng bayan!