In Harvest Moon: Back to Nature you can find Power Berries which will increase your stamina. You start off with only 100 stamina and each Power Berry you find increases your total stamina by 10. The higher your stamina the more work you can get done before you collapse and start gaining fatigue in the videogame.
As a slight bonus your stamina will be completely recovered when you find a Power Berry and there are a total of 10 of them in the game.
It doesn’t matter at all which order you get these in.
You can randomly dig up a Power Berry inside the Waterfall Mine.
You can randomly dig up a Power Berry inside the Winter Mine.
If you go behind the little island the Winter Mine is on and press X you’ll find a Power Berry.
When you watch the Shopping Network on TV one day they will randomly sell a Power Berry for 5,000g.
When you fish at the beach in this videogame you’ll randomly catch a Power Berry.
There’s a tree on Mother’s Hill that will give you a Power Berry if you try to cut it down during the Spring but stop when it asks you to stop.
The first time you win the Swimming Festival you will receive a Power Berry.
If you throw 5 items into the Goddess’s pond she will give you a Power Berry.
You can trade 1001 medals at the Horse Race for a Power Berry.