Having deconstructed characters and advocated screwing with their stats (something close to inherently evil, I'm told) I'd like to revisit the idea. This time with SF supers in a fashion.
A long time ago a community living in an orbital habitat decided to tweak their children's genes to make them smarter. Their space habitat didn't spin fast enough to generate a full gee. Therefore they were carrying around some redundant muscle mass. The plan was to reduce their muscle mass and use the freed up circulatory functions to support a larger brain.
It worked after a fashion. There was a slight intelligence gain. The drawback was that their children began to lose more muscle mass and suffer from lower bone density. Not a huge problem. They reduced the spin of their habitats a bit every year until it was about .1 gee. this worked fairly well. They could reduce the mass of many structures and vehicles. Sure they were fragile but sufficient for their comfy low gee world of weaklings.
Then something happens. They suddenly need security/defenders. Normal humans fill the bill. namely the PCs.
So you could jump 7-8 times higher and further than normal (1/g^-2 as I understand it.) You could lift something on the order of a ton, say a small vehicle. Everything is built to be used in low gravity so most doors and even walls are light plastic or think slats of wood or sheet metal. With a kick you could break in nearly anywhere not rated for vacuum. Most vehicles would seem to weigh about as much as a dirt bike. You could toss them aside.
Hand weapons used by these folks would be a joke. You could snap what they consider a truncheon in your hands. Any body armor you wore would make you relatively invulnerable. Some operatives might design wings to fly with as they are more picturesque than jet packs.
I'm cheating a bit by setting this on an orbital habitat. Let's say most overtly lethal firearms are taboo. You don't want to shoot holes in the hull, portholes or vital equipment. Any ranged weapons are usually nonlethal (think snub pistol with tranq rounds.) The nonlethal weapons are a joke to you. Rubber bullets that's take out an average citizen will barely bruise you.
Psionics such as TK and anything letting you override your body to become faster or stronger will really make you a monster.
There are some drawbacks of course. You have to get used to running in low gravity. Object retain their mass. If you start shoving a ground car it will take some effort to get it rolling and a ground car hitting you will still hurt and knock you flying.
Also if you start making trouble for the scrawny crime lords they will get more off worlders to deal with you (or bots.) GMs may want to experiment with including aliens or cyborgs in this mix (I definitely would.)
In Traveller terms these humans would probably halve their strength stat (at least) and bump their intelligence. In terms of Risus you could simply deem any citizen fighting an off worlder doesn't have the right tools of the trade (high gee muscles) unless they build an exoskeleton.