There's a term you rarely, if ever, hear from the TV commentators, "eye dominance". Here's a quick primer on the term.
We have two eyes for depth perception. It's why objects that are close appear that way and those in the distance are seen that way (I have a wonderful grasp of the obvious). Even though we have two eyes, when it comes to targeting, we use only one eye and it may be left or right regardless of one's dominant hand/arm/foot/leg (insert body part here).
You can find out which eye is dominant for you in a variety of ways but I like the one that was demonstrated to a group of national coaches, of which I was a part, by an ophthalmologist. Since we're talking curling here, and I'll explain that concept later in this post, I ask the athletes to stand on the backboard looking at the opposite end of the curling ice. Usually I have the group at the home end and select an object at the away end, such as a sheet number/letter, clock, pennant/flag etc. What follows is the process to determine one's dominant eye for curling, and notice I said for curling.
- Facing the object, extend your arms at shoulder height.
- Bend your hands at the wrist so your palms face the target.
- Make your fingers touch one another but extend the thumbs.
- Turn your hands at forty-five degrees to one another.
- Overlap your hands so that you create a small "hole" in the crook of your thumbs so you can only see the selected object with both eyes open.
- Now, alternately close your eyes (you may have to get a friend to place his/her hand in front of one eye if you find it a challenge to alternately close them).
With one eye, you will still see the selected object. With the other, it will most likely be obscured in the palm of one of your hands. The eye that sees the object is your dominant eye for that distance. Did you get that last phrase, for that distance?
We learned that "eye dominance" can change over distance. I'm left eye dominant for curling but if I had a 10' putt, I might be right eye dominant. That's why I make sure to do this in the ice area of the curling facility and not the lounge (unless it's about 150' in length). We also learned that the dominant eye can be trained to be one or the other. Apparently that happens with competitive shooters (of the firearm variety).
Virtually 100% of the population is "eye dominant". So what does all this mean for a curler?.It means everything in terms of the relationship between stone and body. Left to its own devices, as a curler slides with the stone in front, the body will align its "dominant eye" behind it. It's one of the "natural systems" which works really well as long as we don't mess it up but more about that below.
A curler that is right handed and right eye dominant (or left handed and left eye dominant) is said to be "same-side-dominant". If one is right handed and left eye dominant OR left handed and right eye dominant, then we use the term "opposite-side-dominant".
If a curler is "same-side-dominant", when viewed from the front as the athlete sides toward the viewer, you will very likely see a good portion of the athlete's sliding foot behind and to the side of the stone. In other words, the stone and the sliding foot are sliding in "parallel" straight lines. If that same athlete is "opposite-side-dominant" then he/she needs to follow behind the stone and again, viewed from the front, the sliding foot will not be visible.
Occasionally an individual will be "significantly" eye dominant. When tested with the procedure described above, that object when viewed by the non-dominant eye will actually be visible to the side of the overlapped hands. When that's the case, you might find an athlete position the stone across the body so that it's directly in front of the dominant eye. Occasionally you'll see this with one or two of the elite athletes on TV.
The point of all this eye dominance talk is this; the body will do the dominant eye/body alignment naturally. When I work with an athlete, that alignment of stone and body is always checked by the "eye dominance" procedure, simply to confirm what I'm seeing. Thankfully seldom do I see an athlete's stone and body alignment inconsistent with what the sport science tells us. When that occurs, it's almost always because a well-meaning instructor, unfamiliar with the premise of this post, has misaligned the athlete.
The very fact that I'm devoting a post to eye dominance demonstrates the importance I place on the topic. But, as stated at the outset, the TV viewer rarely hears anything about eye dominance but from one particular on-air commentator, when it appears that an athlete isn't right behind the stone, the viewer is left with the assumption based upon what is said that the athlete is misaligned. That's very likely not the case. It's much more likely that the athlete is "same-side-dominant". To make matters worse, the camera that follows an athlete from the hack is frequently to the side and it's to the side of the body with the arm that's holding the stone. Then it really appears that the stone and athlete are misaligned. You need to wait to see that athlete from the "front view camera" to accurately assess that stone/body alignment.
If you've been counselled to align yourself relative to the stone in a particular fashion, please make sure it's in agreement with the arm/hand you use to hold the stone and your dominant eye. If it's not in agreement, get it checked with an instructor that's knowledgeable about "eye dominance"!
Before I leave this topic of "eyes", watch the eyes of the athletes you're seeing on TV. Some will focus on the brush full time. Some will divert their eyes from time-to-time. Well, here's what the sport science tells us about that.
It's OK to look away from the target as long as the eye movement away is down and not to the side BUT at the point of release, all eyes must be on the target. If you're not looking at the tsrget when you're releasing the it, you're just guessing. You might, through repeated practice, get really, really good at that guessing but why not put sport science on your side?
Hopefully you'll enjoy watching all that TV curling and be a little more knowledgeable with what you're seeing!
* There is a more complete explanation of "eye dominance" contained in an article of the same title in my coaching manual "A Pane in the Glass: A Coach's Companion".