Most fitness people can be divided into one of three major categories: those who love strength training, people who prefer cardio… and yoga people.

Each offers a slew of benefits and, logically, a combination would work best to create a well-rounded fitness picture.

But if you’re a die-hard fan (not the Bruce Willis kind) of one, you may wonder why you need the other two. And you may fight tooth and nail to avoid getting outside your fitness comfort zone to avoid switching gears.

Maybe you can have your (low-fat, whole grain) cake and eat it, too. But there’s a catch, of course.

It depends on the style of yoga, the intensity, and your starting fitness level.

For example, lying around in the corpse pose for an hour is technically yoga but you won’t gain much strength or improve your flexibility lying on your back with your eyes closed.

If only.

While there’s no disputing the strength required to perform some yoga poses (I’m looking at you, one-arm tree pose), whether or not it strengthens your muscles depends on a couple factors.

First, consider that yoga is a form of body weight exercise, along with push-ups, pull-ups and any other exercise done using only your own bodyweight as resistance.

Just as some calisthenics-type body weight exercises are initially challenging, they get easier with time as you get stronger. Eventually you need added resistance to get results.

Unless you don’t mind spending half your day doing 800 reps – although that won’t get your stronger but merely increase muscle endurance. Two different things.

In general, your ability to get stronger through yoga depends on a couple different factors.

1. Your starting fitness level

   If you’re new to strength training, the challenge of doing a simple yoga pose using your own body weight may be enough to trigger a change within the muscle that makes you stronger.

   If, however, you’re regularly tossing truck tires across a parking lot and performing squats with every 45-lb plate in the gym, you may gain flexibility and mindfulness from yoga but are not likely get stronger as a result because you’re already a beast.

2. Intensity

   To trigger strength, research from the National Strength and Conditioning Association (NSCA) shows a range of two to five sets of six reps or fewer leads to the greatest strength gains. If you’re thinking, oh, great! I only need to do six reps to get stronger, keep in mind it’s because you’re using resistance that makes six reps a challenge. In short: You’re lifting heavy.

It’s tough to translate this guideline into yoga terms, but the limited number of studies of yoga and strength determine its effects is “limited and patchy” as a strength builder.

A 2012 study showed greater leg strength in participants who practiced yoga regularly for eight months but it did not increase strength in other muscles, for example.

The bottom line: Relying solely on yoga to get stronger limits your results. A better idea is to use traditional forms of strength training (e.g. dumbbells, machines) and practice yoga on alternate days.

So strength training Monday, Wednesday and Friday alternately with downward-facing dogging on Tuesday and Thursday gives you the best of both worlds.