I have had great success in using martingale for my sports bets . If you pick your games carefully then you can actually beat the system .
The problem with that approach is that most of the good sports tippsters give out tips at odds less than 2 , and martingaling could increase your bet really quickly that way. But yes , just like trading you could have a slight edge , but in the end even that is very risky.
The best is not to gamble.And if you are damn serious about gambling than I think martingale is the best method(only for short terms) and the worst method(for long period) too!
Check out this video,
https://www.youtube.com/watch?v=tmlscCK7E5cIt will explain you all the cons and pros of martingale.
Just saw that video. It doesn't really have anything to do with martingale in gambling, its completely with respect to trading and doesn't really describe the shortfalls of it for gambling.