When people speak of the physical benefits of exercise, they tend to focus on the three S's: strength, stamina and slimming. With this in mind, their training programs usually consist of weight lifting to build muscle, with some form of aerobic activity to build cardiovascular endurance and burn calories. But there's a second tier of benefits we're starting to value. These include flexibility, coordination, posture and stress relief.

It's not that these secondary benefits weren't always important -- it's just that they're more in the spotlight these days thanks to the growing popularity of so-called "softer" training modalities. Two of the most popular of these are yoga and Pilates.

Yoga, of course, has been popular in the U.S. for decades. I started practicing yoga more than 20 years ago and it's still one of my favorite ways to tone my body and calm my mind. Pilates though is a newer trend that apparently still has many people baffled. I often get letters inquiring about the difference between Pilates and yoga and asking which I recommend. As with most "which do I recommend" questions, the answer depends on your physical goals. Simply put, the difference between yoga and Pilates is that between East and West. Both systems build strength and flexibility; the difference between them is not so much physical as it is philosophical.

A Tale of Two Workouts

Let's take yoga first. Yoga is based on the Eastern idea of moving energy through your body. The more freely the energy flows, the healthier and more energetic you feel. Physical tension hinders the flow; over time, areas of tension in your body can become tight and rigid, even painful. The goal of yoga is to keep the body supple through movement and stretching. But there's another dimension. Yoga is a holistic spiritual discipline with its roots in Eastern forms of meditation. The physical postures, although they condition the body, are really aimed at the mind. They symbolize the goal of living your life in a state of balance and composure. When I spend an hour in a yoga class, I melt into a kind of meditative state and emerge wonderfully relaxed and refreshed.