Semi Circle on the Pilates Reformer can be done with the bar up or down. Which one you do will eventually be entirely up to you and your body's needs. In the beginning though, enjoy and explore it with the bar down. If you feel it only in your legs, remember to work your "up reach" more. Our reach from our back is just as much a part of this exercise as our legs. And you want to reach in both directions so we can truly feel the articulation of our back and working from our center.
Stand in the back of your legs and reach from your upper back.
Both versions bar up or down require 2 heavy springs on. Ideally, place them on the outside of your gear bar so that your seat can roll down through your springs and you don't have one pressing into your seat. Starting with the bar down when you're learning place the balls of your feet on the foot bar and your hands on the shoulder blocks slightly above your shoulders. Work your body out and over your feet similarly to the shape of a shoulder bridge with your arm over your head. Lift your heels up and reach your tailbone long.
To start, roll your spine down and through your springs while keeping the carriage still and your heels up. Press the carriage out until you have a 90-degree angle in your knee. Maintaining the carriage out roll up hips up and then pull the carriage in with your hamstrings and seat while reaching into your shoulder rests. Repeat 2x then reverse. If you would like to try a bigger articulation then place the foot bar up and repeat the same exercise with the bar up. Focus on standing in the back of your legs and reaching from your upper back instead of shoulders.
Be sure to check out more of my online Pilates Reformer exercises. I want to help you continue your Pilates Reformer training!