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Evaluating Movement: What's the First Part of the Body to Start Into the Turn?

One of the categories of student needs in the Student Directed Ski Instruction (“SDSI”) grid is Movement. As a Student-Directed instructor, your activities within this category are to identify the students’ movement needs, and provide the movement instruction needed to help each skier reach his/her goals. Kim Peterson, developer of the SDSI model says, “Providing for needs is only as effective as you are accurate in identifying those needs.” The bulk of most ski lessons consists of the movement tasks – exercises and practice sessions – that you provide to help the skiers meet their movement needs. Thus, the effectiveness of the bulk of your lesson depends on how accurately you assess the movement needs of the students.

Assessing movement accurately is one hallmark of a good instructor. Some instructors may be inherently good at it; for many others, it is a skill that needs to be leaned and practiced. This article is the first in a series of three that will help you to become better and faster at assessing the movement needs of your students. You’ll need a VCR or video camera with clear slow-motion playback, and skiing footage of one or more skiers of the skill level you normally teach. If you have a computer with video capture and individual frame capture, that makes it even easier.

Efficient, effective skiing consists of linked turns in which the skier tips the skis from one set of edges to the other, than balances on the skis while the latter take the skier through an arc. This concept – whether expressed as linked turns, changing directions, pointing the skis back and forth, etc. – is readily grasped by skiers, including those who are self-taught. The manner in which the skier makes the skis go from one turn to the next is the focus of this article. As you watch skiers, you should be able to answer the question, “what is the first part of the body to start into the new turn?”


In a section of linked turns, cue your video when the skier is completing a turn. The skis should be across the fall line, but make sure that there are a few frames to go before your skier starts the new turn. This is your beginning frame (top left in images below). Step through the frames and watch the skier’s downhill ski. Step frame by frame until the downhill ski tilts onto its outside (little-toe) edge (just a minimal tilt is sufficient). This is your ending frame (bottom right in images below).

turn sequence






First, study your beginning and ending frames. In each frame, describe the following parameters:
• The position of each arm; their position relative to the snow and mountain, and their position relative to the torso
• The direction that the torso faces
• The position of the torso relative to the mountain (lean angle)
• The length of the uphill leg (degree of flexion or extension)
• The length of the downhill leg (degree of flexion or extension)
• The direction that the uphill ski points
• The edge angle of the uphill ski
• The direction that the downhill ski points
• The edge angle of the downhill ski

A top PMTS skier will have very few differences in these parameters between the beginning and ending frames. The edge angle of the downhill or both skis will have changed, and the downhill or both legs will have flexed more, but not much else. This indicates that the skier is efficient – moving few body parts to accomplish the beginning of the turn.

A less proficient skier will have more differences between the beginning and ending frames. This indicates less efficiency – the skier needs to move more body parts to accomplish the beginning of the turn, and get the skis onto the new edges.

Now, you’ll step frame by frame through the video, from beginning frame to ending frame. The first time through, watch the skier’s arms. Note their position in the beginning frame. Count how many frames you have to step through until the arms leave the beginning position and start to move toward the ending position. Note this number.

Go back to the beginning, step through frame by frame again, watching the direction that the torso faces. Note the frame number when the torso leaves the beginning direction and starts to face toward the ending direction.

Do this procedure for each of the parameters listed above. Once you are finished, look at the frame numbers. The lowest number indicates the part of the body that starts into the turn. The highest number represents the last part. If the uphill ski direction has the lowest number, you have a stem or wedge entry. If the torso changes direction first, the skier is using upper body rotation to get the turn started.  If both skis change direction well before your ending frame (when the downhill ski tilts to its outside edge), you have a flat twist.

Don’t worry now about the ramifications of each movement permutation – that will come in a later article. For now, simply focus on being able to watch the different parts of a skier as they start a turn.

Slow Motion

Doing this movement assessment in freeze frame is the beginning of your training. Now, see if you can pick out some of the parameters in slow motion. Start by focusing on one at a time. Playing your video segment in slo-mo, can you see the moment when the parameter starts to change from the beginning position and move toward the end position? Watch the video segment numerous times until you can identify with confidence the moment when the change begins. Do this for each parameter.

Next, try to watch for two parameters at the same time, still in slo-mo. Perhaps watch for the direction that the torso faces and the direction of the uphill ski. See if you can identify the start of the position change for each. Then, watch a different combination, perhaps the direction of each ski.

Full Speed

Once you have good success picking out two body parts at once and watching them, try it at full speed. Start again by watching just one of the parameters listed above. Then, try to watch two of the parameters at once in full speed. If you are having trouble, go back to your list of frame numbers. If a lot of the parameters change at approximately the same frame number, it will be hard to distinguish them. If the frame numbers are different for some of the parameters, they should be easier to distinguish from each other.

Further practice

Once you can watch the one turn, watch video of different skiers or turns. Start in freeze frame or slo-mo as needed to be able to pick out the movements that the skier makes in order to start turns.