Last week I began answering a question from a person who hated winter because it was so difficult to continue exercising when it got cold. I mentioned that many people exercise at a local shopping mall during the winter; others buy some type of indoor equipment. In that article, I discussed the pros and cons of exercise bikes (cycle ergometers).

This week, I will discuss other types of equipment that can be used indoors:Treadmills. Until just a few years ago, treadmills were very expensive and found only in hospitals, university research centers and commercial fitness establishments. However, modern technology has made it possible for the average person to purchase a high-quality, inexpensive treadmill for home use.

The major advantage of a treadmill is that it simulates almost exactly the action used for walking outdoors. Therefore, if you are a walker, buying a treadmill will allow you to continue your activity indoors without trying to learn some new exercise technique. Modern treadmills are also very quiet, so you can watch TV while walking if you like to have some distraction for your mind.

One drawback of inexpensive treadmills is that they usually don't go fast enough for joggers. However, they do generally have grade adjustment capabilities, which allow a person to work at very high workloads even at slower speeds. I often use our treadmill on really cold mornings by increasing the grade and walking instead of going outside to jog.

We did have an electric problem about five months after purchasing our treadmill, but I was pleasantly surprised at how helpful the company was in getting it fixed at no cost to us. The key to this kind of service is to buy your treadmill from a well-known, reputable outlet.

Rowing machines. One of the best of the new breed of indoor exercise equipment is the rowing machine. Rowers are usually fairly compact and easy to use, but can give a wonderful aerobic workout if used correctly. The problem with this type of machine is that few of us "row" as part of our daily activity, so the technique of rowing needs to be learned.

One of the major rules for cardiovascular or aerobic conditioning is to involve the large muscles of the body. Since rowing uses the arms, you must learn how to use the larger muscles of the legs along with the arms. Unlike the traditional rowboat you find at a recreation lake, rowing shells (the design model upon which the rowing machine is based) have a seat that rolls back and forth on a track. This allows the rower to intensify the stroking motion by sliding back and forth on the seat, using the power from the powerful leg muscles for much of the energy.

There are two basic types of rowers; those that use a piston (much like a shock absorber on a car), and those that use some type of flywheel resistance device (wind, friction or electric resistance). Both types work well, but the flywheel device probably is more like real rowing because it has a continuous momentum that approximates gliding.

Next week I'll discuss other ways to exercise indoors.