To P57:
A progressive staking system says that you bet more after a loss, and less after a win.

In 2 events both paying even money. You lose the first bet of say $100. You then bet $120 on the next event and have a win.

You profit $20 with a strike rate of 50% on an even money game.

It is not a matter of who you back, just that you bet more after a loss.

To use 37 spins of Roulette as an example. (Making no claims about roulette, just for arguments sake, let's say that we bet on red for 37 spins, a star represents a red, a - represents a loss. On average you will have 18/37 wins)
In this example I will increase after a loss by 1.2, and decrease by .8 after a win.
eg....
W/L Stake
* 10
- 8
* 10
- 8
* 9
- 7
* 9
- 7
* 8
- 7
* 8
- 7
- 8
- 9
- 11
* 14
* 11
* 9
- 7
- 8
* 10
- 8
- 10
* 11
- 9
- 11
* 13
- 11
- 13
- 15
* 18
* 15
* 12
- 9
* 11
* 9
* 7

At the end of this series of 37 bets you have.
Profit of $21.
Average bet of $9.92
Total staked is $367.
Total return of 105.7%. An increase of the straight bet return of 97.29%.

Now the average bet on the wins is $10.8
Average bet on the loss is $9.1.


You are staking 120% more money on a win bet than a loss.


Please Note:
This was a quick 30 second spreadsheet job. Figures rounded to whole numbers for presentation here. All sums were from the spreadsheet, so are not completely accurate for you to work out from this.
Also, just used a perfect roulette session as an example.
The figures 1.2 and .8 are just used as a quick example to show what I meant about betting more on a win than a loss.

Because the odds are constant with roulette, the staking was done on the bet size.
For your examples of tennis matches or horse racing with differing odds, I vary the amount to return not the bet size.