We've all seen Mission Impossible 2 (or at least the preview): Tom Cruise hangs perilously from a rock by his fingertips, the mere slip of a finger bringing about a terrifying plunge to death. Cooooool

Well, rock climbing isn't as glamorous as Hollywood makes it look. It's an intense sport that requires lots of preparation, practice, and concentration. But with this primer, you'll be well on your way to going on your first rock climbing expedition. Having said that, this SYW should not serve as your only reading. Rock climbing after doing nothing more than reading this SYW is like driving a car for the first time after watching a Toyota commercial. But it's a start. After reading this article, we suggest that you enroll in a class and go climbing with an instructor. To protect our toned butts, we repeat: go climbing with an instructor. Unless you like the "full-body cast" look.

1. MAKE SURE YOU'RE PHYSICALLY CAPABLE

Rock climbing requires you to be in pretty good physical shape. You don't have to be Sylvester Stallone or anything (thank God!), but you nonetheless must realize that you'll be using your legs and arms to haul your carcass up the side of a mountain. Halfway up the face of a rock is not a good place to realize that you have the body strength of a wimpy second grader who always gets his lunch money stolen.

Gyms with rock climbing walls are a great place to begin training. You'll get a feel for the amount of physical exertion you'll need to expel, and you'll get to test out different levels of expertise. Once you're comfortable with an indoor rock wall, you can move on to the great outdoors. But before you do that, take stock of your current physical shape and abilities. You may find that you need to work on one or more of the following areas:

Cardiovascular fitness
Flexibility
Strength
Knot-tying ability
Lack of acrophobia

Cardiovascular fitness

You need plenty of endurance for rock climbing, since a big part of the sport involves hiking. So if you're of the couch potato variety, you should start preparing at least 4 weeks before any rock climbing expedition by taking aerobics classes, doing some mild running, swimming, or biking. It'll build up your stamina.

Flexibility

Stretching is VERY important. Stretch everything, especially your legs, arms, and fingers. It may sound weird, but flexible fingers are a must. When you're grabbing for a ledge that's one measly centimeter wide, you'll want finger flexibility. And no, surfing the Internet for porn does not give you more flexible fingers. Instead, you can increase your finger flexibility by crinkling paper into a ball with one hand.

Strength

Though you don't have to be ripped to climb, you do have to be strong enough to push yourself up a wall of rock, so some basic weight training would be useful. One thing that many people don't realize is that while rock climbing, you actually use your legs more than your arms -- so if you have particularly weak legs, that would be a good place to start. However, since most people's legs are stronger than their arms, you should spend about equal amounts of time exercising both the upper and lower body. And since you're doing all that exercise anyway, you might as well tone up your abs. Here's a slightly premature tip: when climbing, push up with your legs rather than pulling up with your arms whenever possible. Your arms will tire more quickly if you don't, and you need to conserve enough energy to finish the climb.

Knot-tying ability

Tying knots is a fundamental skill in rock climbing. It takes practice, but you only need to know how to tie a couple types of knots, and it's really easy to learn. Thursday night "Must See TV" is a perfect time to hone your skills. Grab some rope and sit on your couch. Every time Ross says something dorky, tie a knot. You'll get really good really fast. Here are the five most common knots used in rock climbing.

Lack of acrophobia

If you have acrophobia (that is, the fear of heights), then don't even attempt to rock climb. You'll be miserable and you'll freak out your climbing mates.