The zig-zag theory is composed of a simple idea, bet the team that lost the last game. Sounds brilliant on paper, right? The losing team will probably come back strong the very next game and cover the spread. The theory itself came to prominence during the early 80s and worked wonders on bettor's bankrolls for quite some time. The general consensus over the last decade, however, has been that the theory is outdated and sportsbooks now adjust their lines because of it.

The zig-zag theory itself can be used in any playoff series with a 2-2-1-1-1 format, which includes basketball, baseball and hockey. The theory may be outdated in the eyes of many expert bettors, but it is never a bad proposition to revisit old ideas and try to incorporate them into your gambling. Let's take a closer look at the zig-zag theory and see how it has performed during the 2014 NBA and NHL playoffs.

NBA Playoffs

The NBA playoffs have been a playground for the underdog. Heading into the final games of the first round, the underdog has held series leads in six of the eight matchups and could pull off upsets in five of those series. The zig-zag theory has worked out well during this postseason, and the team that lost the previous game has covered the spread 18 times in 28 tries for an excellent 64-percent win rate.

If a bettor had used the theory during the first round he would have won $700. The Atlanta Hawks and Indiana Pacers series has followed the zig-zag theory to a tee with each team covering after it had lost the previous game. The theory continues to work during this year's playoffs because nearly every series has been a competitive matchup, which is usually not the norm for the NBA. Here is a quick look at the zig-zag record for each playoff matchup.

2014 NBA Zig-Zag Theory Records

Atlanta/Indiana: 4-0

Miami/Charlotte: 1-2

Brooklyn/Toronto: 3-0

Washington/Chicago: 2-2

San Antonio/Dallas: 1-2

Oklahoma City/Memphis: 2-2

Los Angeles/Golden State: 3-1

Houston/Portland: 2-1

Total: 18-10

NHL Playoffs

The NHL playoffs, on the other hand, have not followed the zig-zag pattern at all, and the theory has covered only 17 games in 37 tries for a 45-percent win rate. If a bettor had tried to follow the pattern for every first-round game he would be down well over $500. The only NHL series to follow the pattern was the New York versus Philadelphia matchup, which alternated wins and losses for five games. In fact, only three of the eight first-round matchups came out ahead in the zig-zag theory. Here is a look at the NHL zig-zag records.

2014 NHL Zig-Zag Theory Records

Boston/Detroit: 1-3

Tampa Bay/Montreal: 0-3

Pittsburgh/Columbus: 4-1

New York/Philadelphia: 5-0

Colorado/Minnesota: 3-2

St. Louis/Chicago: 1-4

Anaheim/Dallas: 2-3

San Jose/Los Angeles: 1-4

Total: 17-20

The zig-zag pattern only seems to work during evenly-matched playoff series. The second round of the NHL playoffs promises to be more competitive than the first, while the NBA playoffs should continue to produce close games in favor the underdog. In general, the zig-zag theory may be an outdated proposition in the long run, but it still has some value when handicapping various playoff matchups. The pattern may even continue to be successful during this season's NBA playoffs and can be another tool to use when handicapping a playoff game.

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Read more articles by George Monroy