No need to use martingale in sport betting. The odd is changes so it is not practical to give a much bigger bet just to cover your losses. Instead, you should focus on how to rise your chance of winning so that you can constantly win and have a flow of income.
But at the same time if someone is doing martingale on sports betting then even getting 10 losses is very difficult because we may predict one game wrongly and predicting 10 games wrongly is highly impossible and then think about 30 odd games ! I just wonder, why not go martingale in sport betting !!