04/24/2006 12:00AM

Zig-zag theory now losing its edge


With the second games of the NBA's opening-round playoff series taking place Monday through Wednesday, if you haven't heard about the "zig-zag theory," you're sure to hear it soon (and if you don't stop reading right now, I'll have a self-fulfilling prophecy).

The zig-zag theory, aka "loser-of-the-last theory," simply says to bet the straight-up loser of the previous game in the next game. The logic is that the team that loses will be desperate to make up that game and will make adjustments while the winner might not make any adjustments, as in the case of "if it ain't broke, don't fix it." The Gold Sheet is credited with coming up with the theory, and it worked for years. In the 20 years from 1984 through 2003, the zig-zag theory went 623-504-20 in all NBA playoff games (after the first game was decided) for a very solid 55 percent after tossing out the pushes. First-round games were even more profitable at 286-209-5 (58 percent).

But all good things must come to an end. In 2004, the zig-zag theory went 15-16 in the first round and had a losing record of 32-33-2 overall. Last year, it went a barely profitable 18-16-1 in the first round, and that was only because the last five games were winners, probably well after followers of the system gave up.

The biggest reason for the reversal of fortune (and many sharp bettors made a fortune on the system before it got well-known) is that oddsmakers have adjusted. Knowing that many bettors do bet the system blindly, they shade the lines a few points and suck out some of the value. For instance, after the Heat beat the Bulls Saturday as 9-point favorites, the line came out for Monday's second game and the Heat were favored by only 7. And it's pretty much like that all the way down the line.

The home teams, all of which were favored on Saturday and Sunday, won seven of the eight games. The only game two that wasn't shaded in the direction of the losing team of game one was the Spurs going from -8 in game one to an opening of -8 1/2 in game two vs. the Kings - but that's probably because the Spurs were so utterly dominant in their 122-88 victory. The line as of Monday had moved to -10.

Other than that, the second-game lines are shaded in the direction of the team that lost the opener.

My only wager of the weekend was the Lakers +7 vs. the Suns on Sunday. I cashed that when the Suns won 107-102, and I'm looking to back the Lakers again at +6 and hoping that Kobe Bryant scores more than the 22 points he put up Sunday.

I'm less confident in the other zig-zag plays on the Bucks +12 vs. the Pistons and the Grizzlies +7 vs. the Mavericks, so I'm certainly recommending being selective with the zig-zag.

Zig-zagging on ice

The zig-zag theory is usually applied to NBA playoffs, but it actually worked perfectly in the NHL over the weekend. The four teams that lost their series openers on Friday all came back to win Sunday to even those four series at 1-1.

Making that even more profitable for those thinking outside the (penalty) box is the fact that three of those teams were sizable underdogs - Edmonton and Tampa Bay were well in excess of 2-1 and Anaheim was between 6-5 and 7-5, while San Jose was a slight road favorite at -120 over Nashville.

The other four second-round matchups were after deadline on Monday.

Sports book notes

Wladimir Klitschko completed his comeback and claimed the IBF heavyweight title with a seventh-round knockout of Chris Byrd on Saturday in Berlin, Germany. Klitschko was a 1-3 favorite and fought like it, finishing the job well under the over/under round prop of 10 1/2 rounds.

* Kevin Harvick won Sunday's Subway Fresh 500 Nextel Cup race at Phoenix International Speedway as a 25-1 longshot at Station Casinos. Also noteworthy is that he completed a sweep, in which he also won Saturday's Busch Series race. The Busch Series is considered a training ground for the major-league Nextel Cup circuit, but this year moonlighting Nextel Cup drivers have won every single Busch race.

* If 25 is your favorite number, you could have made a lot of money this weekend. Like Harvick, Stuart Appleby was a 25-1 longshot in the Shell Houston Open, and he led wire to wire to win by a tournament-record six strokes for his second PGA victory of the year.

Race book notes

Last Wednesday, Mark Mataya went 5 for 5 in the first five races at Hollywood Park in the Coast Casinos' weekly contest, winning the progressive jackpot of $22,370 plus $1,000 for having Wednesday's top score. On Thursday, five contestants swept the first five races and split the $41,230 jackpot. Winning $8,246 apiece were Jon Cannida, Marvin Goldberg, G. Goldman, Steve Lipsky, and Dave Datzjow. They also received $500 apiece for having the day's top score.

No Coast weekly contests are planned at this point with the uncertain status of the simulcast impasse between the Nevada Pari-Mutuel Association and Churchill Downs Simulcast Network.

* Eddie Malinowski, race and sports book manager at the Excalibur, said he still plans to use Hollywood Park in his property's free contest on Wednesday even if Nevada isn't taking parimutuel wagers from the track.