There are two main forms of Pilates instruction - one is known as mat pilates and the other is reformer pilates. Mat pilates classes are exercises that can be done on a mat with no additional equipment or resistance and is considered a better option for beginners. Even though you are mostly using your bodyweight as resistance, anyone who has tried to hold a plank for a substantial period of time can attest to it not being easy.
Reformer pilates uses a machine known as a reformer and it basically looks like a torture chamber with pulley and springs. This reformer serves as a way to add resistance to the mat pilates exercises. A few years back I took a handful of reformer classes and it really helped my back and improved my posture.
Pilates is all about control, balance, and alignment with the movements focusing on the core muscles. For those of you who would never take a pilates class, you should know that there is a ton of carryover between pilates movements and traditional strength and conditioning exercises. In other words, if you are looking to improve your deadlift and squat, you may find some gold in practicing pilates movements.
Give the two exercises below a try if you want to add some resistance to your pilates movements without having to shell out the $2500 for a reformer. All that is required here is a resistance band.
Pilates 100 - A staple in reformer pilates and a real challenge to core strength, balance, and stability.
Banded Dead Bug - Dead bugs are a phenomenal exercises to encourage trunk stability and control with pelvic control.