For those of us who are energetic enough to take voluntary exercise, aerobics offers the cardiovascular benefits of a sustained workout with the visual allure of amateur night at Disco Inferno.

If you can't be bothered with all that sweating and stomping, however, Fugumobile has provided an interactive alternative to donning actual lycra in the form of patience-testing time-management tap-a-thon Pump it Up! Aerobics.

Rather than putting you in control of one aerobics class attendee, this game has you monitoring the heart rates of up to nine fitness junkies, each trying to make it to the end of the session without collapsing into a damp puddle of nervous exhaustion

Unsurprisingly, it's your thumbs that will be doing the hard work here, dancing across all corners of your keypad in an effort to keep the class on its feet. Whether you find it enjoyable or not will largely depend on the responsiveness of your keypad, and your fondness for spinning plates.

And one, and two...

Initially, you only have to look after three exercisers, whose heart bars are powered up by holding their respective key ('7', '8', and '9'). As the time passes, more members appear, occupying the slots left by remaining number keys.

As the music increases in tempo and the class grows, the exercisers' heart bars begin to drain more quickly, and at different speeds.

Before you know it, you'll have abandoned your cosy left-to-right recharge system in favour of hammering whichever button corresponds to a flashing red indicator. Which, as seconds tick by, will be most of them.

To the left, to the right...

Rounds of Pump it Up! Aerobics last a matter of minutes, and the difficulty ramps up very quickly, which can lead to premature frustration.

Your experience will also be very dependant on your handset's keypad.

Push down more than one button by accident, for example, and your input will fail to register - an issue we sometimes experienced with our Sony Ericsson K800i's cramped button layout.

The gym is presented well, and some of the characters look agreeably goofy, although we think Fugumobile might have gone overboard with the breast and fat jiggling animations.

Unfortunately, the disjointed three-second loops that populate the soundtrack are awful, which is a problem for a game based around people exercising to music.

If we're honest, Pump it Up! Aerobics doesn't have the stamina to flex with the fittest members of the mobile crowd, though it may hold a passing appeal to obsessive multitaskers.