Fatigue and Athletic Stunts

[Geoarrge]

Because the RAW don't really offer much in the way of chasing/racing.

Concepts
Fatigue. Fatigue is a more temporary form of exhaustion. It stacks with exhaustion and follows the same progression of effects, except at level 6 you are unconscious, rather than dead.
Fatigue Saving Throw. Whenever you perform an athletic stunt, you must pass a Constitution saving throw or suffer one level of fatigue. The DC begins at 5 and increases by 1 for every athletic stunt you have performed since your last long rest. If you fail the saving throw by 10 or more points, you suffer one level of exhaustion instead of fatigue. If your fatigue saving throw DC has increased above 10, a short rest will reduce the DC back to 10.
Recovery. Any effect that heals at least one level of exhaustion heals all fatigue, including a long rest. A short rest heals 1d4 levels of fatigue. A lesser restoration spell may be used to heal 1d4 levels of fatigue.

New figures to track: 2. Fatigue, which can be put alongside exhaustion; and the running fatigue saving throw DC.

Athletic Stunts
Sprinting. Once a round, you may add five times the result of a Strength (Athletics) check, in feet, to your normal movement. If using the Dash action, add ten times the result of the Athletics check.
Marathon Running. Over a ten-minute period, add one-fifth of your base movement to the result of a Strength (Athletics) check, multiplied by one-tenth of a mile, to determine the distance you can cover in that period.
Combat. You may be required to make a fatigue save for every full minute spent in combat.
Racial Abilities. Some racial abilities may be modified to use this mechanic.

 

[Xeviat]

Interesting. I was checking sprinting records against d&d rules to figure out a sprinting rule recently. I'll check on it at home.

 

[Geoarrge]

For the most part it seems to work out, although it does allow a perfectly average character (+0 to everything) to slightly beat Usain Bolt's speed by rolling a 20.
Relevant Wikipedia article: https://en.wikipedia.org/wiki/Running#Limits_of_speed

Rather than make the formula more complicated, I'd suggest the following interpretations:

1) A round is six seconds, but not all actions take exactly six seconds. Sometimes it makes sense to suppose that an action like a high-rolling Dash+Sprint actually overlaps the next round for a few seconds.
2) Like arm-wrestling, some contests are such a pure test of ability that it makes no sense to roll dice for a variable outcome. I'd suggest the 100-yard dash fits this category.

The "thirty-second barrier," which you can see with the significant drop in average speed between the 400 and 800 meter races (see the table in the article), I think is modeled reasonably well by shifting from the round-by-round to 10-minute rules. Either you start pacing yourself for long distances, or you start failing saving throws and rack up fatigue levels which also slow you down.

Coming back to the perfectly average character, let's see how marathon time works.
(Base speed 30 / 5) + (Athletics check:10) = 16; *.1mi = 1.6 mi/10 min, or 9.6 MPH.
Holding a steady speed like that would make for a 2:43:45 time, but this would ignore fatigue.
At level 1, he'd suffer disadvantage to ability checks (roughly -5?), reducing his average speed to 6.6 MPH.
At level 2, base speed would be halved, reducing average speed to 4.8 MPH -- in most cases, dropping to a 4MPH fast walk before hitting this point is likely to be the best strategy.
At level 3, disadvantage to saving throws, which translates to quickly gaining further fatigue levels if he's still pushing himself, which could end in incapacitation.

A more plausible marathon time for this perfectly average character would involve holding 9.6 MPH for three 10-minute segments before failing the first saving throw (total distance 4.8mi, time 0:30:00),
knowing he's not likely to pass two more saves in a row but maybe gambling on one segment at 6.6 MPH (+1.1 mi, +0:10:00, total 5.9 mi),
then going at 4MPH until the final stretch. Assuming he can gauge himself correctly, that's one more segment at 6.6 MPH (+1.1 mi, +0:10:00) before hitting fatigue stage 2, and even if all further saves are failed, at least three at 4.8 MPH (+2.4mi, +0:30:00).
Total: 9.4 mi in 1:20:00, not counting the 4MPH stretch in the middle. Accounting for that adds up to a total marathon time of 26.2mi in 3:32:00. About 60th percentile for a young adult male.
http://www.heartbreakhill.org/age_graded.htm

It's somewhat interesting to note that using these rules, having a higher base speed is not an insurmountable advantage; every 5 feet of base movement is equivalent to +1 on the roll.



Just for comparison, let's check a 5th-level barbarian. Relevant proficiencies (in both Athletics and Constitution saves, let's say +6 for both), plus by 5th level also gets a boost to base speed. Also, this is the level typically considered to be borderline superhero, so I'd say it's fine if any real-world records are broken here.

Strength(Athletics) +6, base speed 40, average Dash + Sprint speed of 240 (27.2 MPH)
Marathon speed of 14.4 MPH, can probably hold for at least 6 segments before hitting Fatigue-1 (total 14.4mi), fatigue-1 speed of 11.4 MPH, hold for 2 segments (total 18.2mi) before hitting Fatigue-2 (9MPH), then 4 segments before next speed drop at Fatigue-5 (total 24.2mi/2:00:00). Filling in the gap with a period of fast walk (About 5MPH for speed 40), brings the total time to 2:24:00. Still not breaking any records but quite good.

But I more or less ignored the ability boost/feat the barbarian would have gotten at 4th level. Mobile, with the +10 speed, is certainly the strongest choice, which would push him above current human speed records, but not tremendously so-- a 2:00:00 marathon, and a sprint speed of 29.5 MPH, on average rolls.

For any character wanting to maximize their speed by these rules, Mobile is generally the strongest choice, although those without proficiency in Constitution saves might want to start with Resilient[Constitution].

 

[dave2008]

Did you figure encumberence into this. D&D usually a certain amount f gear bearing worn/ carried. Neither Bolt nor marathoners are carrying much additional weight