Rowing is one of the best ways to shrink the 'thunder thighs' some women worry about at one time to another, according to a top fitness trainer.

The inner thigh machine that is usually such a popular piece of fitness equipment with ladies at the gym is not going to get rid of saddle bags, Shelley Greenfield writes in the online magazine Post-Bulletin.

Instead Ms Greenfield recommends using an indoor rowing machine, which utilises all major muscle groups.

Ms Greenfield goes on to say that the best aerobic exercise to help burn fat from around the thighs is any cardio training intense enough to bring your heart rate in the 70-80 per cent range of its maximum for 15 to 20 minutes.

"Rowing is excellent," Ms Greenfield continued. "The more muscles involved in the activity, the more adaptation your body has to do, which is what keeps you off the plateau."

Indoor rowing machines have great calorie burning potential because they exercise larger muscle groups across both the upper and lower body regions, helping to tone the thighs and buttocks and firm up the arms and all the back muscles together.