By Dorene Internicola NEW YORK (Reuters) – Few workout tools are more versatile than kettlebells, the ancient market counterweights that were hoisted by Russian strongmen and now can be found in weight rooms at gyms across the country, fitness experts say. But kettlebells, which come in varying weights, are often thought mistakenly to be the preserve of strongmen and extreme athletes. Steve Cotter, a former Kung Fu competitor and the founder and director of the International Kettlebell and Fitness Federation, said part of the problem was that the kettlebell was marketed as a hard-core tool that implied intensity. But the San Diego-based author of “Kettlebell Training: 95 exercises for strength, toning, stamina and weight loss,” said novices should not be deterred.