Thinking of giving fitness trends CrossFit or Zumba a go? You might be better off staying on the couch.

CrossFit and Zumba have exploded in popularity around the globe with millions of people tackling CrossFit's high-intensity training or Zumba's high-intensity dance workout in pursuit of a body beautiful or just to be fit.

But should these fitness fads, or just heading to the gym come with a health warning?

New statistics from the Accident Compensation Corporation (ACC) show a staggering rise in the number of claims from injuries Kiwis have suffered while exercising.

In 2013 ACC handled 23,325 claims made by Kiwis who were injured while "fitness training" or in the gym, data released to the Sunday Star-Times shows.

This was a rise of about 10,000 claims on the previous two years.

The jump has prompted ACC and industry body Exercise New Zealand to launch a research programme into why workouts are doing us harm.

On average, ACC spends about $330 million on sport and recreation claims annually. In 2013 gym and fitness injuries were the third highest total of claims for injuries in the sport and recreation sector behind rugby and football.

Exercise New Zealand chief executive officer Richard Beddie said there had been a 35 per cent increase in people undertaking exercise programmes in the past five years.

"We don't actually know for certain why this is happening but we have some ideas, and we want to test them before leaping into solutions."

In January this year it was reported a US CrossFit athlete, Kevin Ogar, was paralysed from the waist down when he severed his spine attempting to complete a heavy weight lifting technique called a snatch.

Les Mills' globally successful BodyPump class has also had its share of injuries.

Its instructors are warning members not to pack up and put weights away while the class is still running after a weight was dropped on someone lying down, the Sunday Star-Times has been told.

National health and safety regulator Worksafe New Zealand received 12 complaints related to gym operations in 2013 and a further 15 in 2012.

The 2012 complaints include an incident at a BodyPump class where someone was "poked in the eye" with a weight by another user.

Les Mills human resources manager Marilyn Manning said from January to March this year there have been four injuries related to weights in its gyms with two in BodyPump classes.

Manning said Les Mills took health and safety seriously including appointing an external health and safety expert to review its systems, policies and practices to identify gaps or improvements.

Beddie said he was still working through the detail with ACC on how the research programme will unfold but it should begin in June.

They will discuss with gyms why they think there are more injuries and investigate accident log books at gyms to get a clearer picture.

Once ACC and Exercise NZ have the findings they can then put together a programme to help bring injuries down, he said.

* This article has been edited since it was published to remove erroneous information in relation to CrossFit.