One of the so-called axioms of table tennis is this: Against balls to your middle, if you are close to the table or rushed, favor your backhand; if you are not close to the table or have time, favor the forehand. It's a useful guideline for most players. (Note - a ball to the middle is a ball hit at the transition point between your forehand and backhand, usually the playing elbow.) However, if you have a strong forehand, you might want to cover the middle with it, even when rushed or close to the table. How do you do this? You have two options.
Historically, the standard way was to step off the table to give yourself time to get into position for a forehand, and hit a late but strong forehand. This especially worked for loopers, who can use both spin and speed in powering a forehand loop from a few feet further back than usual. Hitters, however, had a problem with this as hitting the ball late made their shots a lot less effective than their usual hitting at the top of the bounce or earlier. So many hitters, especially pips-out penholders, developed techniques where they'd take the rushed forehand from the middle closer to the table by shortening their stroke, leaning to their left (for a righty), and rotating their upper torso backwards. They would also use this technique when stepping around their backhand to play a rushed forehand.
Some loopers experimented with this, such as 1993 World Men's Singles Champion Jean-Phillipe Gatien, who was famous for looping from close to the table. Since then generations of world-class players have copied that, and many high-level matches become battles over who can loop from closer to the table. The first one that backs up gives the other player time to wind up as well as having more ground to cover. So these days many world-class players (including most of the best ones, pretty much all of them loopers) favor the same technique pioneered by hitters and then adopted by loopers such as Gatien, which is to simply shorten their swing and lean to the left (for righties) and rotate their upper torso to cover the middle with their forehand while staying close to the table. Like hitters, they also adopted this for when stepping around their backhand to play a rushed forehand.
Here's a classic example of this technique, with Gatien himself. Go to the point starting 33 seconds in, and see Gatien's third shot, the forehand 36 seconds in. (Gatien's the lefty on the far side.) Most players, of course, will not do this with as much power as Gatien.
This is also an example of where an old dog can learn new tricks - both older players reading this, and this coach as well. I don't know if I qualify as an "old dog" yet at 53, but it wasn't long ago that I was still coaching most players to take these middle balls farther off the table with their forehands. Now I teach both ways, but favor taking the ball quicker with a shorter stroke. Who did I learn this from? Another "old dog," 1971 World Champion Stellan Bengtsson, now a top U.S. coach.