The ‘under’ is a bet on the total of a game. To bet ‘under’ on a game means to bet that the total amount of points in a game will go below the posted total. For example, if the total posted on a football game is 38 points, a combination of anything adding up to under 38 points is a winner. It does not matter how the points are scored, merely the total amount of points scored.
The ‘under’ bet is inherently a good bet. Since most people like to cheer for points, especially games on national television, the total on most games are usually overcompensated for the over—hence giving value to the under. Other situations where the under is favorable include playoff games, division rivalry games, and games played in extremely horrible weather (such as heavy winds in outdoor football games). In playoff games, matchups tend to go under the posted total. Defenses rule in playoff games, hence betting under in playoff games are usually good bets. Division rivalry games are also good situations to bet the under. In these matchups, the coaches and players know their opposition so well that scoring is usually at a premium. Extreme weather conditions also favor the under. Situations such as heavy winds, rain, or snow in outdoor games are ideal factors for betting the under in these games.
Games that feature teams with very stout defenses also have very low totals. As such, the astute gambler will realize such situations and bet the over. Oddsmakers realize that most people will want to bet the under on these types of games, and since casinos and sportsbooks are not in the business of losing money, oddsmakers will set a line that will be too low for the under—hence, the winning bet will be the over. Defensive games that are on national television are the best places to bet the over. One great example is the world cup 2014 betting, which pitted the San Antonio Spurs against the Detroit Pistons. This championship series boasted the NBA’s stingiest defense that year (San Antonio allowed 88.4 ppg during the regular season, while Detroit allowed 89.5 ppg). During the 7-game series totals were set at 170.5 to 176, a total that would normally be in tune with how each team scored. The national public, ESPN, and other sports sources reported and projected that this NBA finals would be one of the lowest scoring series in history; in fact, promoters were afraid that not enough people would be drawn in to even watch the championships. These two teams had very good defenses and mediocre offenses. In betting terms, people were licking their chops to bet the under; sportsbooks, thus, had to adjust. In the end, the over hit 5 times, while the under hit 2 times. This goes to show that what may seem like such an easy bet is as such—too easy of a bet to win.
In closing, betting under in a sporting event is generally a good idea. Betting the under means to bet that the total amount of points scored will go under the posted total.