Hi Lo and BodyAttack

Lots of impact, lots of leaping, breathlessness and 'the burn' are what draw people to these two different approaches to aerobics.

Twenty years ago any gym that aimed to encourage both sexes would have had a class called aerobics where the emphasis was on loud music, high-energy dance moves and slightly more whooping than you get in the free weights room. These days the last remnants of that approach can be found in the likes of BodyAttack and Hi Lo which both work on the same principle (loud music, lots of calorie expenditure) but with a difference that says a lot about the way the gym business is going. The benefits of both are improved circulation, stronger heart and lungs, lower cholesterol and increased bone density (providing you don't break any in the process).

BodyAttack follows the tried and trusted format of other Les Mills exercise routines (such as Bodypump and RPM) which means that you warm up and then go through a certain number of basic routines followed by a brief abs and cool-down finale. The music is changed every few months to keep it fresh but the exercises remain the same. Once you've been to one you can walk into a Bodyattack class in Beirut or Bangor and immediately know what comes next. In fact what comes next is a mix of work on the spot, forward backward advances and movements circling the studio. There's a huge amount of hopping involved which in itself is very high impact and not recommended for those with joint problems or weak shins. Good cross-trainers are essential. BodyAttack's choreography is not challenging - even the most clodhopping will pick it up straight away - which leaves the emphasis firmly on working up a sweat.

If you're used to the Les Mills approach to courses (such as Bodypump, RPM or BodyAttack), then Hi Lo will come as a bit of a surprise. Hi La is very much open for interpretation and will vary wildly from one gym to the next and one instructor to another. A normal programme would kick off with 5-10 minutes of warm-up, then a peak of 20-30 minutes of target heart range dancing, followed by 20 minutes of body sculpting (a muscle-stretching floor session) and ending with cool-down and stretches.

The Hi Lo refers to the mix of high and low intensity moves which is a coded warning that the class may get a bit frenetic (lots of leaping). It also usually means that there will be some challenging choreography with the instructors allowed to get as creative as they choose. In practice that means that classes will be a lot more fun for regulars, but can be off­putting for newcomers unless they're particularly good at picking up new moves. Definitely the place to be for girl band wannabes, not necessarily so right for hairy truckers with two left feet.

Depending on the nature of the group you find yourself in you may also find that part of the requirement of either of the above is to make more whooping noises than a coach load of gibbons arriving at Disneyland. It's all part of the fun.