Working out with a gym ball, also known as a "fitball", is becoming a "keep-fit craze" across the UK, according to the Huddersfield Daily Examiner.

Describing the gym balls as "reminiscent of space hoppers" - the 1970s children"s fad - writer Andrew Hirst reports that they are a popular fitness accessory for developing increased core strength.

Touted by a number of exercise companies as an all-round fitness tool, fitballs often come complete with illustrated exercise charts for additional guidance.

They can be used to strengthen abdominal and hip muscles, as well as the lower back and thighs.

"It"s good for toning and muscle-building, but you"d need other types of exercise for other parts of your body or if you wanted a cardio workout," health centre administrator Justine Warhurst told the newspaper.

"If I had to describe it in a phrase I"d say it"s body conditioning with a ball!"

According to the News & Observer, watching TV at home while perched on a gym can help strengthen abdominal and back muscles.

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