I'm worldbuilding low fantasy with technology level of the early middle ages. Very few of the people could tap into psionic power, which makes them faster and stronger than common people. Average psionic users could be three times stronger than a strong human, while the most gifted ones could be up to a dozen times stronger. The psionic users could sustain their power for a limited amount of time, then it has to rest and recuperate. The stronger the exertion the shorter the period. Think jogging vs sprinting.
Luckily psionic are rare, something like 1 in 1,000 for a weak psionic, 1 in 10,000 for a medium one, and 1 in 100,000 for a strong one.
Despite their rarity they are over represented among nobility, due to the usefulness for their fighting prowess. All the children born with psionic potential are trained and join the nobility, regardless who their parents are. Psionic talent is somewhat heritable, children of psionic parents have larger chance to be psionic but the odds are low. Most psionic parents have normal children.
Since strength doesn't come from the muscles, what dark age weapon would suit best for a 7 year old girl, which has the strength of a dozen strong men?