For participants/teams to score the most runs. However, instead of a baseball bat, participants will use a tennis racquet to hit a tennis ball.
Other Skills:
Speed
Coordination

Set up 3 bases and 1 home plate just like a baseball diamond.
The distance of the bases from one another depends on the skill level of the participants.
Divide the participants into 2 equal teams.

1. Have one team start in the field, and the other starts as the "racquetting" (batting) team.
2. Have the fielding team spread out in the infield and outfield.
3. Participants will not be throwing to individual bases, so having basemen is not necessary.
4. Select one participant in the fielding team to be the pitcher, or the leader can be the pitcher.
5. The racquetting team will be standing behind the field and to the side.
6. The first participant will go to home plate and pick up the tennis racquet.
7. The pitcher will lob a tennis ball to the "racquetter".
8. The racquetter will swing at the tennis ball. If they miss, it is a strike, and just like in baseball it is "three strikes, and you're out". However, unlike baseball, it is not 3 outs to end an inning. The inning ends when all participants have gone up to racquet.
9. When the racquetter hits the ball, they will drop the tennis racquet and start to run towards first base.
10. One participant from the fielding team will run and pick up the tennis ball.
11. The fielding them has to make three passes to three different participants on their team.
12. They will all count out loud.
13. The participant that picked up the ball will throw it to one of their teammates, and when they catch it (or pick it up if they didn't catch it) the team will say "One". Then that participant will throw to another, and when they catch it, the team will say "Two", and then they will throw to another participant and the team will all say "Three" when they catch it.
14. When the fielding team says "Three", the racquetter has to stop running.
15. Tennis baseball rules dictate that a runner has to stop running when they hear "Three". Even if they are between bases, they will stop exactly where they are and stay there until the next racquetter hits the ball.
16. Whenever they get to a base, they have to stop there and do 5 jumping jacks before continuing to run.
17. If the fielding team says "Three" when they are doing jumping jacks, then they stay at that base.
18. The next racquetter goes up to home plate to racquet. When they hit the ball, they start running to first base and the racquetter already in the field starts to run to their next base. When the fielding team says "Three", they both have to stop.
19. Runners cannot pass each other.
20. Racquetters score a point when they touch home plate.
21. Switch the racquetters and fielding team when all participants on the racquetting team have gone up to racquet.
22. Play for a set amount of "innings" or time.

Variations:
Fielding team has to do more or fewer throws.
If they make three throws before the racquetter gets to a base, they are out.
Use a beach ball or wiffle ball instead of a tennis ball.
Fielding team has to throw it back to their pitcher in order for the turn to be over.

Adaptations (General):
Encourage "fielding" teams to actively include all participants in the passing and counting.

Adaptations (Blindness/Visual Impairment): Consider tying a plastic bag around the tennis ball to allow participants who are blind or visually impaired to hear it. Allow these participants to swing at the ball on the bounce. Have another "racquetter" guide low-vision participants.

Adaptations (Mobility Impairment): Encourage participants with a mobility limitation to move in a way which is most comfortable for them. Running may be challenging but they may be able to walk or wheel. Once they reach a base, have these participants perform a fitness challenge that corresponds with their abilities and strengths.