But for individuals suffering from lower back problems, research suggests they may need to think twice before stamping their ticket to ride on the popular workout machines.

The elliptical trainer, sometimes called a cross-trainer, is a piece of stationary exercise equipment that simulates walking or running without causing pressure to the joints.

Researcher Janice Moreside is a physiotherapist who’s been a clinician for more than 30 years. She said she’s found that while the majority of people who come in who use the elliptical like it, there’s a subset who say the opposite, and point to the fact using the trainer hurts their back.

Moreside, a University of Waterloo PhD candidate, works with Waterloo professor Stuart McGill whose specialty is spine research, specifically the lumbar spine or low back.

The research was part of a larger study looking at the effect of hip mobility on the low back which Moreside presented Friday at the 2010 Congress of the Canadian Physiotherapy Association in St. John’s, N.L.

Kids are more fickle than adults when it comes to exercise DVDs. Adults are mostly concerned with “getting the job done.” For kids, as soon as it stops being fun, they’re over it. In fact, a kids’ fitness DVD not only has to be fun, but also a little funny. It needs to be challenging, but not too complicated. Cool animation and other gimmicks are also a plus. To find one that meets their criteria and saves your pocketbook, borrow from the library, rent from the video store, or buy used when you can.

To help you in your search, here are my reviews of three kids’ fitness DVDs:

Learn to Hip Hop, Volumes 1 & 2 (Bayview Entertainment)
This dance-based DVD presents authentic and challenging hip hop choreography. It’s formatted more like a dance class rather than a fitness class. The instructors break down the moves without music first, then put them all together with the music later. What is unique is that the instructors presenting the material are kids. Their ability to effortlessly lead and cue the choreography is remarkable. Professional choreographer Shane Sparks appears on the DVD as well. Volume 1 is great because the choreography and dancers manage to look cool without looking in any way inappropriate. Some parents might find a few of the outfits and moves in Volume 2 to be inappropriate for their kids.
Ages: 8 – adult
Pros: Kids leading kids!
Cons: The choreography is very challenging. Non-dancers may feel intimidated or discouraged. In addition, although they mention the importance of warming up, the warm-up is barely there in Volume 1 and absent in Volume 2.