Oh dear. Basketball shorts is all DH has. "Short shorts" are probably not going to fly, so what recommendation do you have for him in general? Some sort of bike short to go UNDER the basketball shorts?
Plenty of men's running short options that aren't short shorts.
https://www.runningwarehouse.com/catpage-MRSHORT.html
You could go with medium or long length. The in-seam will tell you how short short it is. When my legs were thinner I preferred 3in inseam. These days the leg strength workouts have caused my legs to be a little wider and 3 in inseam doesn't work like it used to (my legs eat the fabric). So now I wear "short tights".
https://www.runningwarehouse.com/catpage-MRSFIT.html
They also make 2-in-1 shorts with the benefits of "short tight" but covered up by an attached running short.
https://www.runningwarehouse.com/catpage-MR2IN1.html
What does "bank time" mean?
It's a mental state of mind when running a "positive split" in a race. Let's use an extreme example for illustrative purposes.
The goal is to run a 10k in 60 minutes.
Person A runs the first half in 30 min and the second half in 30 min. They completed the race in "even" splits because the first and second half were equal.
Person B runs the first half in 40 min and the second half in 20 min. They completed the race in "negative" splits because the first half was slower than the second half.
Person C run the first half in 20 min and the second half in 40 min. They completed the race in "positive" splits because the first half was faster than the second half.
Person C is likely to set out in the race at what is likely a too fast of pace for them. But despite the pace being too fast, they feel good and continue on. At some point they're going to realize their pace was originally too quick. In a moment of "not clarity" they are going to assure themselves everything is ok, because they "banked time". The goal was 60 min and here they are having finished the first half in 20 min, banking an extra 10 min above and beyond the average 30 min per half needed.
The problem is that the body's physiological response does not follow a linear relationship (both HRvPace and Lactate threshold come to mind as power relationships rather than linear). Running 10 seconds/mile too fast does not have an equally offsetting response to running 10 seconds/mile too slow. Such that if Person C runs the first half in 20 min, despite that second half being 40 min they're likely to be in a world of hurt. Additionally, I would argue that Person C's fitness by doing the first half in 20 min suggests their fitness is far better than a 60 min 10k. Such that their poor racing pace strategy led to a sub-optimal performance.
This is meant as a simple example. There are extenuating circumstances where a 20 min first half and 40 min second half could make sense. Perhaps the first half is all downhill and the second half is all uphill. Or perhaps the first half has a massive tailwind and the second half a massive headwind. But removing those other possibilites and just looking at say a flat two loop course, then you'd prefer to be either Person A (even) or Person B (negative) from a physiological standpoint. It's hard to be Person A (even) and hit maximal performance because you need really good data to determine where that pace should be. So in most cases, Person B (negative) is the strategy. It doesn't have to be an extreme example (like the 20 min + 40 min), but even something like 32 min and 28 min is a decent flat two loop 10k strategy. Far better than a "bank time"/positive split strategy.
