If you’re bored with the gym and fed up of aerobics, you might like the challenge of high intensity interval training. Fiona Adams puts her muscles to the test

I am writing this on the morning after my first experience of GRIT strength. For those of you with a fertile imagination, this does not involve lugging bags of heavy stone, clad in overalls and hard hat, but a new example of HIIT (high intensity interval training), a form of exercise that is currently taking the fitness world by storm.
Regular readers will know that I’m not adverse to a bit of pain in the interests of research, so I embraced the class with gusto, lifting weights, throwing burpees and doing press-ups with the best of them. Happily – so far at least – I am not walking like John Wayne.
HIIT advocates claim short, hard-core workouts can deliver better, quicker overall fitness than more traditional methods, such as aerobics or running, and after 30 minutes my heart was really pounding.
The class I took is one of three new GRIT sessions (strength, aerobics and plyometrics, all from the stable of New Zealander Les Mills, a former athlete), which have been introduced by the Lensbury in Teddington in response to calls from members who wanted more from their workout – they run three classes a week.
The onus with HIIT is on the individual to work to his or her absolute limit. There’s no hiding at the back – if you’re not prepared to give it 100%, it’s not for you.
Another popular choice is CrossFit, which I first experienced on holiday in Morocco at the Robinson Club, Agadir, a hotel that took its fitness programme very seriously. I found myself worshipping at the altar of AMRAP (As Many Rounds As Possible). I tried two hour-long sessions where you exercised hard for just 15 minutes, completing increasing rounds of the exercises given (burpees, goblet squats, V-ups…).
CrossFit is curiously addictive as there is an added competitive element. Not only are you pushing yourself, but you find out how you’ve done compared to others. Devotees regularly compete against other clubs.
You can find local classes at Blitz Crossfit in Twickenham, Performance CrossFit in Sunbury, and CrossFit2012 in Kingston.
If you fancy revving up your exercise regime, why not try out one of the programmes listed here? Most offer taster sessions and all should ensure you’re up to speed with safety and technique before letting you loose.
QueenAx
This is available at Virgin Active and Soho Gyms and uses a frame as a tool in the routine, including the floor, sides and ceiling.
The work stations may look like instruments of torture but think of them as a revved up form of circuits, where you try suspension and support training, oscillation as well as stretching and joint mobility.
TurnFit
This new centre in Guildford uses the Lagree Fitness Method developed by French-born, but US-based Sebastien Lagree, who has been honing his training techniques since 2001.
The routine is done on a Megaformer machine and combines core strength, endurance, balance, strength and flexibility in each controlled exercise, a little like hard-core pilates.
Michelle Obama and Ben Stiller are said to be fans. A new site is due to launch this autumn in Finsbury Square.
Speedflex
This (relatively) new centre in West Byfleet offers HIIT using Speedflex machines, which were developed by US baseball player Darren Holmes, orthopaedic surgeon Dr Jim Silliman and mechanical engineer Joe Worley.
Classes are aimed at all levels and include low-impact, high-intensity, cardiovascular workouts using resistance. Each machine is fitted with heart-rate monitors and participants are encouraged to work at their maximum potential to complete a circuit in faster times. Need to train in town? Visit the Lombard Street centre in the City.
Insanity
These classes (run by Janey Simpson in Esher) will work you hard, but are suitable for all levels. There are three sessions a week and each one is different, but all include endurance and plyometrics, strength and balance, agility and coordination and abs and core, divided into 2-3 minute segments with 30 second pauses.
No equipment, only body strength. No booking, £8. You can telephone Janey on 07764 612349 or visit this website to find local classes.
Check the links above to find all the information you need to pick up a local class