Muscling the ball when forehand looping
Several players I coach use too much arm when they loop. Looping is a full-body shot, where you use your legs, waist, shoulders, arm, forearm, and wrist for power. However, the sequence is important - always from bottom to top, large muscles to small muscles. Players who use too much arm and forearm try to muscle the ball with those muscles instead of using the legs, waist, and shoulder rotation to power the ball with their body weight and large muscles.
One cure is to essentially make your playing arm and upper body rigid early in the stroke, forcing you to use your lower-body muscles. Those larger muscles will throw your upper body and arm into the shot like a whip, and then you can relax the upper body and let it go naturally.
Another way to fix this problem is to focus on taking the ball in the back of the forehand hitting zone, in front of your back leg. This forces you to keep the arm back rather than use it early in the stroke. If you stroke with the arm muscles too early, you'll contact the ball more in front of you.
Probably the best cure for this, and most other stroke problems, is to 1) watch videos of top players doing it so you can get a visual image of proper technique; 2) work with a coach; and 3) practice, Practice, PRACTICE!
Jim Butler vs. Ariel Hsing