среда, 11 декабря 2013 г.

Side-Glide Nose-Up (SGNU)


Just as important as side-lying nose-down balance is side-lying nose-up balance. This drill builds on the skills you learned in SGND and will get you balanced and comfortable on your sides while your blowhole is exposed. But you should practice SGND until you are balanced and very comfortable with it before trying SGNU.
Eschew the snorkel this time. Push off in SGND position. As soon as you are balanced, turn just your head until your nose points straight up and you can breathe freely (figure 4.7). Nothing else should change when you turn your head. Don’t roll onto your back. Don’t lift your head as you turn it—even the slightest lift will undo your balance. Check for good aquatic posture. Stay in this side-lying nose-up position for the length of the pool. Do this drill on both sides of your body.
If you are losing your balance as soon as you turn your head to breathe, try the following strategy: Starting in SGND position, make sure that your lungs are full of air when you turn your head to take your nose out of the water. Do not exhale immediately; instead, hold your breath in the nose-up position while you mentally check your feedback tools. Once you are satisfied that you are well balanced, exhale slowly and begin breathing normally.

Feedback Tools

 
• Use the same feedback tools you would use for SGND, except that when you are balanced, your head should be in almost exactly the same position as in the back-balance drill—ears under the water, nose pointed straight up, and water line at the tip of the chin and crest of the forehead.
 

Experiment a Bit

 
After you have spent some time with the SGNU drill with a tight line,
experiment as you did with the previous drills—alternate between tight-schlumpy-tight, noting the effects, both positive and negative, of each of these postures. Also experiment with varying the amount of buoy pressure you need to feel fully supported by the water. As before, relaxing your posture tension may erase the sensation of support.
 
FOCUS POINT  Downward Angle Arm Extension
 
In the side-glide drill descriptions, I indicated that the extended arm should be at a slight downward angle. This is a departure from the conventional wisdom of extending the lead arm straight toward the far end of the pool. Most adult swimmers have range of motion issues in their shoulders that affect the choice of the arm extension position. Several considerations strongly favor having the extended arm at a downward angle, both in this drill and throughout most of your freestyle endeavors. They are as follows:
 Avoiding injury. Extending the arm horizontally toward the far end of the pool (or at any upward angle) can pinch the shoulder tendons between the upper-arm bone and the shoulder socket. Doing this thousands of times per day is a cause of chronic pain for a large number of swimmers. But extending the arm at even a small degree of downward angle greatly reduces the risk of an impingement.

 Mechanical advantage. A shoulder joint at or near the end of its ROM has poor mechanical advantage (in other words, you exert lots of muscular force but get very little work done). Extending your arm at a bit of a downward angle keeps the shoulder away from the end of its ROM, increasing mechanical advantage during the first part of the stroke.
 Skiing uphill.As the swimmer glides forward through the water, an arm extended at any degree of upward angle will mean that the onrush of water will hit the bottom surface of the hand and arm, which will tend to raise them. Due to the long lever of the extended arm, this will lift the upper body (and drop the hips)—a bit like skiing uphill. Alternatively, extending the arm at a bit of a downward angle will help your hips hug the surface.

 Energy use.Choosing an extension line near the end of your shoulder ROM (horizontal or upward angle) requires lots of extra internal tension to maintain the position. Choosing a bit of a downward angle greatly decreases the internal tension (and, consequently, the energy) required.

 Fatigue-induced hip drop.While the extra internal tension required by a horizontal or upward angle extension is sustainable for short durations, for longer durations it soon results in fatigue stress. The usual response is to release some core body tension and break out of the balanced streamline position by letting the hips drop. This relieves some of shoulder stress but greatly increases total frontal resistance. If you had to choose between having a spindly little hand a bit out of streamline below the rest of the body or your big ol’ hips dragging deep, which would be your preference?
 
 

It is often hard to judge your arm extension angle yourself. Have a swim partner give you feedback about your extended arm position. Then experiment with various amounts of downward angle in your arm extension line while monitoring how much tension is required in and around your shoulder to support the position. What you are looking for is just enough downward angle to allow you to maintain good aquatic posture and to keep your hips glued to the surface.

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