Expansion and contraction are the most basic movements in life. Inhale, exhale. Tides in, tides out. Flowers open, flowers close. Birth, death. Wherever you look, listen or touch, even within your own body, there is Exp/Con going on all the time. This movement has no resistance - that comes with MFFR (molding, flowing, flying, radiating). So Exp/Con is a rhythmical, repetitive movement. What you can do, however, is to vary the size, speed, and visibility of those movements.
Use a scale of 0-10 with 0 being the most extreme contraction you can accomplish and then begin to expand out to 10, which is the most extreme expansion you can physically make. Reach the stars!  Some natural expansions may be at the molecular level and others may be continental shifts.
You can also vary the speed you do them with. In nature, which Chekhov mirrors a lot, there are things that expand very quickly - think of a hummingbird's heartbeat - and others that are very slow - the seasons are exp/con of climates, the geological movement of the earth is on glacial timescales. Within your own body, there are very slow ex/cons, such as your digestive cycles, and very fast ones, such as the neurological operations in your brain. Some are very irregular, such as your brain waves, and others are very regular, your heartbeat. Play with all these variations.
Finally, you can do these totally internally (stand still and move nothing physically but allow your imagination to see yourself moving at the maximum you could do physically). We call this veiled, in this case, fully veiled. We always start out our physical work fully UN-veiled, that is with the maximum visibility of your physical action. After we get the physical movements down with all the variations mentioned above, then we begin to veil it. Think of veiling as putting a covering over a strong light bulb. The bulb always shines at the same bright intensity, but by putting a veil over it, you see less light. So you imagine a veil covering your 100% physical effort so that someone who is watching would see less movement - but you are still doing the maximum ex/con you can do.
With all of these variations, there are two extremes, which are the maximum limits of your own physical ability, and an unlimited of intermediate steps. It's easiest to put it on an integer scale, like 0-10 or 1-7 or something that helps you imagine it, but there are many more in-between steps you could try. Never reduce your possibilities with any kind of limits. Always explore as much as you can.