The exercises were conducted with the aim of improving postural- and movement control and awareness of the lumbar spine in both treatment groups. Both groups received nine 30-minute therapy sessions, during which they performed a series of exercises from an exercise catalogue. The exercises were selected based on their compatibility with the AF-system. Each patient performed impairment-specific exercises. The AF group received additional AF feedback during both the therapy sessions and the home exercise program, by combining the exercises with games designed to target movement control, body awareness, and stabilisation exercises.

The control group performed the impairment-specific exercises without AF. The control group was able to receive conventional visual feedback, such as use of mirrors, as deemed appropriate by the therapists but no AF.

An inertial measurement unit (IMU) system is the basis of the augmented feedback (AF) system, where the IMU-system communicates with a laptop using a bluetooth dongle. The corresponding software includes therapeutic games. Movements of the lower back and pelvis by the patient are used to control an avatars movement or the graphical interface in computer exercises. The AF-system provides real-time feedback regarding the patient's performance and helps to rectify incorrect execution of the exercises. The intervention took place at a physiotherapy clinic and in an home environment. In the physiotherapy clinic the patients exercised under the supervision of the physiotherapists. They continued the exercises at home as home exercises.

Movement control was quantified using the ratio of the range of motion (ROM) of the stabilized lumbar spine (ROMLS) over the moving body segment, the hip (ROMHip) during the movement control test (lumbar spine (LS) over the hip)

Postural control was quantified using the mean absolute deviation of lumbar angular displacement (MAD)