@Sigilbreaker26
If you take into account that all Martial Arts, that don't weapons, is close combat. So you have to shrink the circle of "long range" to extend to arm/leg length and "close range" to the the elbow/knee joints
In that regard, strikes made at length with the hands/ feet when you aren't in grapple/hold would now be considered "long range" and any strikes while in a grapple/hold are considered "close range".
I think what the coach is saying is that Maria prefers to use knees and elbow strikes, which can generally inflict more damage with less strength behind it, over kicks and punches. Like how a well aimed elbow can easily split open someone's forehead and fracture the skull, while a full strength punch from the same person may still cause a cut but not to the same extend and is less likely to cause a fracture.
Also remember that she says makes up with accuracy
and critical strikes to compensate. Meaning Maria has to move into an opponent's range to strike, so she has be accurate enough to move in and deal a staggering (literally) amount of damage to either KO her opponent or allow for her to move out of range all without taking any major hits herself.
She brought up muscle flexion, honestly just a clunky translation in context , not because her accuracy increases her speed, but because she can strike faster than a guard can be put up effectively.
Of course speed equals force, but Maria lacks the mass in the mass x acceleration = force, when you consider most of her opponents are larger male fighters.