This is obviously a baseball term depicting a batter getting up to the plate and swinging with everything he has and not holding anything back.
Before I had a real job, I used to play competitive league softball. I was almost a real ball player and almost had some skills at the game. Nonetheless, I batted 4th which in most baseball realms means that you were the best hitter on the team. The idea was to let the first 3 people bat and get on base and then the 4th hitter would hit a home run and score all 4 players. That was the idea anyway.
At the time I was in my early 20’s and could bench press twice my weight. Now I can bench press a chicken leg or a cell phone. Ha. Then, I was eating food to try and gain weight and working out 3-5 times a week with my muscled friends. Now I try not to eat so I will lose weight. It’s amazing how the cycles of life happen.
Anyway, the feeling it was to swing a bat with everything you have is a lot like life today when you absolutely try as hard as you can at what you are doing. I am sure there is some doctor that could name what happens to the cells of the body when you are giving your all either mentally or physically at some project. It is like a shot of adrenaline to the soul. When you experience this adrenaline rush in life or business, you will sleep better and be more content in life. There is something both physical and spiritual about trying as hard as you can at something.
The other side of this subject is the fear of failure that holds you back. Many people live an entire life with a fear of failure that keeps them from really experiencing true satisfaction and the joy of a job or project well done.
Find something that you can give your best to and watch how you feel afterward. KT