The following exercises help when learning to keep time.
Just as a drummer can twirl his stick to delay the next beat and thereby vary his rhythm, a pianist can raise his thumb or pointer finger or raise, lower or turn his wrist.
During such movements, the little finger can stay close to the keyboard as an anchor.
A way of playing tight, even and staccato bar chords is to fix the wrist and bend at the elbow to raise and lower the forewarm. Practise that with the staccato exercise as shown in this drawing.
When the left hand plays a chord for the duration of a full note of half note, the right hand can play staccato 1/8 or ΒΌ notes, or a silence. That is long chords with short notes, or a long chord with short fill-in notes, like a call and response. Practise that with two 1/8th notes as in this drawing. Think of the two 1/8th notes as one beat.
To help hold a chord for a half note, dip the wrist for the second beat. Practise this rhythm with the dip wrist.
Play a silence for a half beat by raising the pointer finger or resting the thumb on the edge of the paino.
Play a long chord followed by a short note like this.
Practise timing exercises with four quarter notes to each bar but with one of those beats shortened, lenthened or silenced.
Turn the wrist sideways to rock from left to right, from thumb to fingers with this exercise.
Combine two rhythms such as these.
Practise playing a rhythm with the left hand then keep that going as you improvise note playing with the right hand.
Counting beats, raising fingers, dipping or turning the wrist, nodding the head and tapping the foot all help when learning timing. But those movements are not needed once timing has been learned. Timing becomes automatic.
