I have several favorite props for Pilates depending on the focus of the class or the needs of a private client. They all add variety and challenge; conversely they can be used to make some of the exercises more accessible.
I like to use a Pilates ball primarily for ab work. If the client has no major back or neck issues I like to use the ball under the low spine/sacrum area. This allows clients to bring both legs up into table top or straight up and do movement that focus on using the abdominals, especially lower abs. To add challenge, arms straight up or bent elbows on the floor with hands straight up increases ab work because of the extra balance required. I also like the Franklin ball behind the shoulder blade area to do more upper ab and oblique work. Using the ball under the feet during bridging adds quite a bit of challenge and balance work.
The Pilates ring is a great prop for so many exercises, especially inner thigh/pelvic floor. I also add that to my arm series for isometric strengthening. The ring is a great tool to accompany work on the reformer. Specifically squeezing holding the ring in between the ankles during Feet in Straps adds inner thigh work. Using it outside the ankles during the same exercise adds outer hip work. Placing the ring in between the inner thighs, close to the knees while doing Kneeling Side Splits is also very effective.
The Theraband is very versatile. I incorporate it into reformer classes by looping it around the foot bar for arm work off the reformer or during footwork. It is also useful during exercise on the jump board to challenge coordination. An example of simple resistance is to hold the band tails in both hands with arms straight up while jumping back and pulling the band apart by separating the arms, moving towards t-arms, release to center when returning. Or use the band around the arch of one foot (still hold both tails with both hands) and keep that leg straight up in the air while doing single leg jumping with the other leg. Pulling the band down gently with the foot flexed adds calf and hamstring stretch. Adding to that position, do an upper body lift holding onto the band tails as you jump away from the board, and lower the upper body on the return.
The gliders are another prop to add challenge and fun. Standing sideways in front of the reformer to hold the foot bar for balance, use the gliders for single leg back and forward lunges. Face the Foot Bar for single leg side lunges.
The small Franklin ball (which is similar to the size and density of a lacrosse ball) is a fabulous way to stretch fascia before and during Pilates. You can start by sitting on the edge of the reformer facing the side and put the ball under the arch of one foot. Roll the foot out, from in front of the heel bone to the ball of the foot, either circling or moving front to back or side to side. Doing this stretch actually helps loosen the hamstrings. If you get to a painful spot, hold and put a little pressure into the ball to break up the knottiness. Another great way to use the ball is in between the shoulders and the shoulder rests during footwork. While you press the carriage back you are putting pressure into the ball with the shoulders, like a mini deep tissue massage, so position it at the top of the shoulder on the trapezius muscles – the part that someone might touch and tell you that you are tight and need a massage.
Because movement in Pilates should almost always be slow, and it is always controlled, these props can assist clients who tend to move faster than is optimal.