After being used consistently by the Russian military for over 200 years, the Kettlebell has shrugged off its iron curtain image and reinvented itself as the trendiest new fitness tool.

Looking like cannonballs with handles, celebrities love them and it’s not just macho types like Sylvester Stallone and Matthew McConaughey either. The likes of Penelope Cruz, Jennifer Aniston and Geri Halliwell are all fans and even Premier League giants Chelsea and Liverpool have incorporated them into their training regimes

So what is the difference between exercising with a kettlebell and lifting barbells or free weights?

Unlike a dumbbell or barbell, the kettlebell’s centre of mass is offset from the handle which means the weight constantly pulls against your hand and requires not only strength and co-ordination, but also the use of the other muscles through your arms, shoulders and your core stabiliser muscles.

Adherents claim that exercising with a Kettlebell uses around 600 muscles and exercises the cardiovascular system as well. You don’t have to be super strong to train with kettlebells as they come in a range different sizes and weights, starting at 4kg and going right up to a massive 48kg.

Users start with the basic Kettlebell swing, a conditioning movement performed either one-handed or two-handed. The kettlebell swings at arm’s length from between the legs to approximately head-level, with the legs, hips and lower back providing the motive force. The arms should barely even move except to hold on to the kettlebell.

They then move on to perform the Kettlebell snatch, an exercise similar to a traditional snatch in which the weight moves from a lower position to over the head with the arm extended and the Kettlebell jerk, a competition lift which, like the kettlebell snatch, culminates with the weight overhead at arms’ length.

Most daunting of all is the Kettlebell Power Clean Squat Thrust, a complicated lift that requires first lifting the kettlebell to about chest height, then squatting and then finally thrusting the kettlebell to above the head

As with any free weights, there are some risks involved with kettlebells, but these can be minimised by having proper instruction.

Kettlebell detractors claim that traditional weight training methodologies are superior to recent developments in kettlebell lifting. They say kettlebells are inferior to dumbbells, from the point of view of strength trainers who need a safe, ergonomically-designed and easily-adjustable tool and maintain that the supposed benefits of kettlebell lifting are more easily and safely achieved with dumbbells.