Wednesday, November 01, 2006

Physicists Reveal Fundamental Flaws in NBA's Synthetic Basketball


Synthetic NBA basketballs introduced this season — and despised by many players — are less lively, more slippery when damp, and bounce more erratically than the traditional leather balls, according to a preliminary study by University of Texas at Arlington physicists.

When Shaquille O’Neal, Kobe Bryant, Dirk Nowitzki and other superstar NBA players griped about the league’s new synthetic basketball, Mavericks owner Mark Cuban contacted James Horwitz, Chairman of the University of Texas at Arlington Department of Physics, to request a study of the properties of the new and old balls.

Horwitz responded setting up a UTA Physics investigative team, designating Professor Kaushik De as UTA Physics “MavBalls” project leader. According to the UTA physicists’ tests and preliminary results, the players’ complaints may be justified.

De, Horwitz, and their students have found:

* That the new balls bounce 5-8% less high than typical leather balls used in past seasons, when dropped from a little over four feet, requiring players to make adjustments to their shots and rebounds

* That the new balls are tackier when dry, which can improve grip, but are less absorbent. This causes the balls to become slippery when they get exposed to sweat or other moisture during a game. Such sudden changes in players’ ability to grip the ball could cause mistakes and turnovers during play. (Leather balls, on the other hand, become easier to grip when they become moist.)

* That the synthetic balls bounce 30% more erratically, leading to less predictable trajectory, which can cause problems during dribbling, rebounding and passing. The bounce is most erratic when the grooved surfaces on the ball, with the embossed Spaulding logo or NBA logos are involved.

Some of the ball’s shortcomings could potentially be corrected easily. Decreasing the depth of the ball’s embossing would reduce erratic bouncing. Over-inflating the ball to 14.5 psi, rather than the regulation 8.5 psi, is enough to get the synthetic ball to match the bounce height of a leather one. But improving grip on the synthetic compound will probably be a trickier problem. Keeping the ball dry with towels and frequently changing the game ball, as suggested by Cuban in his internet blog, Blog Maverick, may help reduce the slippery grip problem this season.

The study is a stark contrast to the assertions by Spalding, the ball’s manufacturer, that it is superior to leather basketballs. The UTA team however has not done any durability studies, which is one of the primary characteristics Spalding claims makes the synthetic ball better.

The UTA physicists point out that their current results are preliminary, and they are in the process of performing more extensive testing to definitively evaluate the controversial new basketball. Among other tests, they plan to subject the balls to aerodynamic tests in UTA's engineering department wind tunnel.

An executive summary of the study De, Horwitz and their students performed is posted on the UTA web site, as well as an article profiling the two physicists and their motivation for taking up the quest to evaluate the new NBA ball.

2 comments:

  1. This isn't relevant to the topic but i am researchin ginformation about the physics of basketball an writing a report on it as my A level physics coursework. i am wondering if you could give me amy links or book to look at because there isn,t much available. One area I haven't found out any physics afecting the shoes and the payers.

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  2. Suck that they elected to use balls made with the skin of animals again.

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