From the PHB:
"High Jump. When you make a high jump, you leap into the air a number of feet equal to 3 + your Strength modifier if you move at least 10 feet on foot immediately before the jump. When you make a standing high jump, you can jump only half that distance. ... In some circumstances, your DM might allow you to make a Strength (Athletics) check to jump higher than you normally can."
So 20 Str can do a Standing high jump of (3+5)/2=4 vertical feet. What would it look like to do even more than that (in some circumstances)?
The Korean game Show Physical:100 has just showed me. Enjoy.
Actually those number don’t sound too bad when we start comparing them to some real life athletes.
For reference:
a 20 STR gives a standing high jump of (3+5)/2=4 feet or 48 inches.
a 16 STR gives a standing high jump of (3+3)/2=3 feet or 36 inches.
Now, for the 2022/2023 Season, the average high jump of the NBA was 39.2 inches. So a 16STR PC has a jump pretty much average in the NBA. The 20STR PC with their 48-inch vertical jump ties the highest ever vertical jump for an NBA player (Micheal Jordan & Darrel Griffith).
Now turning towards the video, I am going to make the following assumptions:
1: Center of Mass (CoM) is located at half the height of the body (makes math easier)
2: To successfully land on their feet, the person needs to lift their CoM an additional 18 inches over the mat.
3: I estimate the height of the athlete in the video to be approximately 5 ft 6inches (66 inches), based on the height of the mat and the where the mat comes up to in relation to their body. This puts their CoM at a height of 33 inches.
We are told the height of the mat is 134 cm. Which converts to approximately 52.75 inches. So I will round that up to 53”
Now, based on our #2 assumption, the athlete needs to raise their CoM to a total height of (53+18) 71 inches.
Since in our #3 assumption we’ve estimated the starting CoM at 33 in, the athlete needs to raise their CoM (71-33) 38 in.
This is just above the high jump of a 16STR PC, but doable by an 18STR PC.
If we make a PC with same height as assumed for the athlete in the video, 5ft 6in (66in), and give them a 20STR, the can make this jump onto a mat of 63in
33 (starting height of CoM) +48 (jump height) -18 (overage required for landing).