Pump it up 點解 ?

1/ 把...打足氣; 把...加大
(source : Babylon-Pro)
2/ ((俚語)) 使振奮, 使興奮
The lively debate really pumped us up. 這場熱鬧的辯論著實令我們振奮
3/ 打氣
pump up a tire 為輪胎打氣
4/ 運動』熱中於健身活動
I saw him pumping up at the gym. 我看到他在體育館裡健身
(source : http://cdict.freetcp.com/wwwcdict.cgi?word=pump)

非常Easy!Pump it up mean 打氣!