Slide monkey or thief vault is a clever little movement. Early in my training it eluded me. I struggled to learn it for the longest time. It’s not overly difficult; however, it was psychologically challenging for me. The slide monkey is included in the fundamental movements of parkour. When we teach a basic vault progression, this vault is always included. However, it is one of the more complex vaults that we have to learn.
The object is to approach an obstacle such as a rail or a low wall moving parallel to it. First, you place your inside hand on the obstacle. Then the inside leg plants on the ground. The outside leg swings up providing lift to the body. Both legs come over the obstacle. In the air the hands pass the obstacle under the body, so when you come down on the other side you're still holding it with the inside hand. The leg that was outside, is now inside and lands first. Because the outside leg is the prime mover, the thief vault pivots the hips from being parallel to the obstacle to being perpendicular to it once exited. This redirects the body as well.
The thief vault is used any time you need to get over a low wall. It doesn’t work as well to get up on top of a low rise. This is because the legs are far from being under your center of gravity at the highest point of the movement. When the goal is to pass over a low obstacle onto the ground on the other side, this maneuver works well. Since it redirects the direction of the hips and therefore your momentum, it is a great vault if direction change is the goal. The other application for a thief vault is sengree or monkey play. They are beautiful vaults. The legs swing in a large ark, and the body seems to hang for a moment in the air. Because of how the legs work in the vault, it allows for easy and quick transitions between other vaults.
Again the same wrist faults we always talk about in parkour are present here. They may not be as bad in the slide monkey because the vault is gentler. Rarely will the forces involved in say a kong vault be applied to the wrist in a slide monkey. In the top of the movement where the body weight is positioned over the hands, there is a tendency to collapse in the chest and internally rotate the shoulders. This is a weak position and can cause injury. Finally, a leg of foot clip will end your fun and flow really quick. A clip is where you don’t get high enough with the feet and they trip over the obstacle instead of clearing it. To protect the wrist use proper wrist prep exercises. For the shoulders remember the chest proud cue. One of my favorite cues for that is that there is a light on your chest, like ironman, and we need to point that light up at the sky for this vault. To prevent foot clipping, remember a good strong swing with the outside leg. Also, don’t be afraid to plan on putting your foot on top of the obstacle when learning the movement.
The thief vault is one of our more rudimentary vaults. When I teach a vocabulary of vaults, it is almost always included. However, it took me months from the time that I started training to the time where I mastered the thief vault. This was because it has a psychological factor to its toughness. The fear of falling in a thief vault is very real. I remember clearly the practice where I finally mastered it. We were on a playground in the heart of OSU campus. The playground is no longer there, but my memory is. Now the slide monkey is ubiquitous with my flow work.