Catching Fly Balls Is A Lot Like Rocket Science

Every Little League outfielder knows the feeling.

With the crack of the bat, you see the ball jump into the air. You take a few quick steps forward. Then, as you watch the ball continue to rise faster, you feel your stomach sink knowing that this one is going over your head. What went wrong?

How our eyes, brains, arms and legs combine to track and catch a fly ball has stumped scientists for more than 40 years.

A new study supports the original theory of it all while offering some practical tips.

By watching fielders shag pop flies, researchers have noticed a few interesting quirks. First, great ballplayers will not sprint to the exact spot on the field where they think the ball will land and then wait for it. Rather, they usually adjust their speed to arrive at the landing spot just as the ball arrives.

In fact, a previous study asked fielders to stand still in the outfield and predict where a fly ball will land. While they did poorly on that test, they then demonstrated that, when allowed to move, they were able to go catch similar fly balls. So, the tracking and prediction mechanism seemed to require movement of the player.

Years ago, physicist Seville Chapman proposed a model to explain how players manage the path of a fly ball so that they arrive to intercept it at just the right time. His theory, called Optical Acceleration Cancellation (OAC), used the acceleration of the ball through the vision field as a guide for player movement.

As a fielder watches the ball rise, he moves either forward or backwards so that the ball moves at a constant speed through his field of vision. If he moves too far forward, the ball will rise faster and may eventually fly over his head. If he takes too many steps back, the ball will appear to rise slower and will drop in front of him.

By managing the ball's position with his movement, a fielder will end up at the right spot at the right time. This explains why the stationary fielders could not predict where the ball would land, as they did not have the benefit of OAC.

If we ask real fielders how they knew where to run to catch a ball, they may not respond with, "Well, I simply adjusted my relative field position to keep the tangent of the vertical optical angle to the ball increasing at a constant rate." So, to test the OAC geometric equations against real life, researchers led by Dinant Kistemaker of the University of Western Ontario, compared the predicted running paths from their mathematical simulation with the real running paths of fielders observed in a previous study.

"We have found that running paths are largely consistent with those observed experimentally," Kistemaker told LiveScience. "Largely, and not completely, because the start of fielders is somewhat strange: They tend to step forward first, irrespective of the fact that they have run either forward or backwards to catch that fly ball."

The research is detailed this month in the journal Human Movement Science.

Will those first few steps forward doom the Little Leaguer to years of fly ball nightmares? Actually, it might be our brain's method of improving its viewpoint.

"For a fielder, making a step is a way of changing the magnitude of the optical acceleration, while preserving its informative value," Kistemaker clarified. "A faster rise of the optical acceleration above the detection threshold may outweigh a possible initial step in the wrong direction. Making an initial step forwards is not only easier than making an initial step backwards, but might also be a better choice."

So, if you're now coaching Little Leaguers, be patient. Their brains may still be learning the math.

Please visit my other sports science articles at LiveScience.com

Runners Pace Themselves Into The Zone

Most regular runners can tell you when they reach that perfect equilibrium of speed and comfort. The legs are loose, the heart is pumping and it feels like you could run at this pace forever.

Researchers at the University of Wisconsin-Madison now have an explanation for this state of running nirvana, and we can thank our ancestors and some evolutionary biology for it.

For years, it has been thought that humans have a constant metabolic energy rate. It was assumed that you would require the same total energy to run one mile, no matter if you ran it in 5 minutes or 10 minutes. Even though your energy burn rate would be higher at faster speeds, you would get there in half the time.

Turns out, however, that each person has an optimal running pace that uses the least amount of oxygen to cover a given distance. The findings, by Karen Steudel, a zoology professor at Wisconsin, and Cara Wall-Scheffler of Seattle Pacific University, are detailed in latest online edition of the Journal of Human Evolution.

Steudel's team tested both male and female runners at six different speeds on a treadmill while measuring their oxygen intake and carbon dioxide output. As expected, each runner had different levels of fitness and oxygen use but there were ideal speeds for each runner that required the least amount of energy

Overall, the optimal speeds for the group were about 8.3 mph (about a 7:13 minutes per mile) for males and 6.5 mph (9:08 min/mile) for females.

The most interesting finding: At slower speeds, about 4.5 mph (13 min/mile), the metabolic efficiency was at its lowest. Steudel explains that at this speed, halfway between a walk and a jog, the runner's gait can be awkward and unnatural.

"What that means is that there is an optimal speed that will get you there the cheapest," Steudel says.

So, why is a zoology professor studying running efficiency? Steudel's previous work has tried to build a theory of why our early ancestors evolved from moving on four limbs to two limbs, also known as bipedalism. She has found that human walking is a more efficient method of getting from point A to point B than on all fours. It might also have been an advantage for hunting.
This latest research could offer some more clues of how we moved on to running. Steudel explains, "This is a piece in the question of whether walking or running was more important in the evolution of the body form of the genus Homo."

Please visit my other sports science articles on LiveScience.

The Cognitive Benefits Of Being A Sports Fan

When was the last time you listened to a sporting event on the radio? If given a choice between watching the game on a big screen HD or turning on the AM radio, most of us would probably choose the visual sensation of television.

But, for a moment, think about the active attention you need in order to listen to a radio broadcast and interpret the play-by-play announcer's descriptions. As you hear the words, your "mind's eye" paints the picture of the action so you can imagine the scene and situations. Your knowledge of the game, either from playing it or watching it for years helps you understand the narrative, the terms and the game's "lingo".


Now, imagine that you are listening to a broadcast about a sport you know nothing about. Hearing Bob Uecker say, "With two out in the ninth, the bases are loaded and the Brewers' RBI leader has two strikes. The infield is in as the pitcher delivers. Its a hard grounder to third that he takes on the short hop and fires a bullet to first for the final out." If you have no baseball-specific knowledge, those sentences are meaningless. 

However, for those of us that have grown up with baseball, that description makes perfect sense and our mind's eye helped us picture the scene. That last sentence about the "hard grounder" and the thrown "bullet" may have even triggered some unconscious physical movements by you as your brain interpreted those action phrases. That sensorimotor reaction is at the base of what is called "embodied cognition". 
 
Sian Beilock, associate professor of psychology and leader of the Human Performance Lab at the University of Chicago, defined the term this way: "In contrast to traditional views of the mind as an abstract information processor, recent work suggests that our representations of objects and events are grounded in action. That is, our knowledge is embodied, in the sense that it consists of sensorimotor information about potential interactions that objects or events may allow."

She cites a more complete definition of the concept in Six Views of Embodied Cognition by Margaret Wilson. Another terrific overview of the concept is provided by science writer Drake Bennet of the Boston Globe in his article, "Don't Just Stand There, Think".


In a recent study, "Sports Experience Changes the Neural Processing of Action Language", Dr. Beilock's team continued their research into the link between our learned motor skills and our language comprehension about those motor skills. Since embodied cognition connects the body with our cognition, the sports domain provides a logical domain to study it.


Their initial look at this concept was in a 2006 study where the team designed an experiment to compare the knowledge representation skill of experienced hockey players and novices. Each group first read sentences describing both hockey-related action and common, "every-day" action, (i.e. "the referee saw the hockey helmet on the bench" vs. "the child saw the balloon in the air"). They were then shown pictures of the object mentioned in the sentences and were asked if the picture matched the action in the sentence they read.

Both groups, the athletes and the novices, responded equally in terms of accuracy and response time to the everyday sentences and pictures, but the athletes responded significantly faster to the hockey-specific sentences and pictures. The conclusion is that those with the sensorimotor experience of sport give them an advantage of processing time over those that have not had that same experience.


This may seem pretty obvious that people who have played hockey will respond faster to sentence/picture relationships about hockey than non-hockey players. But the 2006 study set the groundwork for Beilock's team to take the next step with the question, "is there any evidence that the athletes are using different parts of their brain when processing these match or no match decisions?" The link between our physical skill memory and our language comprehension would be at the base of the embodied cognition theory. 

So, in the latest research, the HPL team kept the same basic experimental design, but now wanted to watch the participants' brain activity using fMRI scanning. This time, there were three groups, hockey players, avid fans of hockey and novices who had no playing or viewing experience with hockey at all. First, all groups passively listened to sentences about hockey actions and also sentences about everyday actions while being monitored by fMRI.  Second, outside of the fMRI scanner, they again listened to hockey-related and everyday-related action sentences and then were shown pictures of hockey or every day action and asked if there was a match or mis-match between the sentence and the picture.


This comprehension test showed similar results as in 2006, but now the team could try to match the relative skill in comprehension to the neural activity shown in the fMRI scans when listening. Both the players and the fans showed increased activity in the left dorsal premotor cortex, a region thought to support the selection of well-learned action plans and procedures. 

You might be surprised that the fans' brains showed activity in the same regions as the athletes. We saw this effect in a previous post, "Does Practice Make Perfect", where those that practiced a new dance routine and those that only watched it showed similar brain area activity. On the other side, the total novices showed activity in the bilateral primary sensory-motor cortex, an area typically known for carrying out step by step instructions for new or novel tasks. 

When playing or watching, we are actually calling on additional neural networks in our brains to help our normal language comprehension abilities. In other words, the memories of learned actions are linked and assist other cognitive tasks. That sounds pretty much like the definition of embodied cognition and Dr. Beilock's research has helped that theory take another step forward. Beilock added, "Experience playing and watching sports has enduring effects on language understanding by changing the neural networks that support comprehension to incorporate areas active in performing sports skills."


So, take pride in your own brain the next time you hear, "Kobe dribbles the ball to the top of the key, crosses over, drives the lane, and finger rolls over Duncan for two." If you can picture that play in your mind, your left dorsal premotor cortex just kicked into gear!