**2.1. Hardware configurations**

Approach for Locomotion and Spine based on Optitrack2

22 Innovations in Spinal Deformities and Postural Disorders

the subsequent development and upgrading of the system [6–8, 17, 27–30].

as multiple strides in gait) has been included as well [8, 27, 28, 31].

system/skeleton model and the actual capability to use them as a clinical tool.

our research group having in mind the following three specific 'GOALS':

achieve the greatest possible number of clinically relevant parameters.

**2. Materials and methods**

orders of the spine.

NaturalPoint Inc., OR, USA.

2

protocol and procedural techniques formerly presented by D'Amico et al. [7] together with

The actual implementation of the GOALS system and related biomechanical skeleton model allows for the analysis of the full human skeleton 3D posture and movement taking into account the 3D spine shape considering each vertebral level as well as the postural attitude of the head, the trunk, the pelvis, the legs and when necessary the upper limbs. It is able to per‐ form a multi‐sensor approach, fully integrating data deriving from force platforms, surface electro‐myography (SEMG) and foot pressure maps. In addition to kinematic measurements, depending on the specific analysis requirements to be fulfilled, this can also include the mea‐ surement of the forces, torques and electro‐muscular activity of participants or patients. By means of data fusion and optimization procedures, all these inputs can be used in the skeleton model to assess internal joint forces, torques and muscular effort. This allows for the correla‐ tion of the full‐functional evaluation of subjects with their morphological characteristics.

The possibility of assessing and extracting mean behaviours for cyclic or repetitive tasks (such

The applications and the valued contribution in clinical‐functional diagnoses of differ‐ ent classes of posture, locomotion and spine‐related pathologies using the GOALS system together with its original biomechanical approach have been presented in literature [6–8, 27–31]. Thousands of patients are currently analysed and followed up with this methodology. The highly sophisticated and demanding computing tasks to acquire data and to solve the whole skeleton model's equations and algorithms can be approached even on relatively low‐ cost powerful PC workstations. Examples of multi‐sensor quantitative functional descriptions of pathological cases are presented to describe the actual level of development of the GOALS

As described in Section 1, the GOALS system has been specifically developed for the use of an opto‐electronic stereo‐photogrammetric measurement approach within a clinical environ‐ ment. This project stems from over 25 years of biomechanical‐clinical research conducted by

(1) Find a way to use stereo‐photogrammetry to measure the posture and/or movement to

(2) Include in the measurements, a detailed description of the 3D shape of the spinal column in relation to the description of the whole‐body posture, to appropriately study the dis‐

hardware) fully founded on the

The GOALS system can present different configurations depending on the requirements necessary to be fulfilled for the specific analysis that needs to be performed. In general, for the analysis of erect standing posture coupled to measurements of lateral and forward bending movements to evaluate the functional mobility of the spine, a configuration with six specially designed infrared TV cameras (IR TVC) (0.3 Mpix resolution) is sufficient to have a fully automated measurement process. When more complex movements such as gait, running, jumping, cycling, and so on are of interest, a 12–16 IR TVCs (1.3 Mpix at 120 fps) configuration has been found to be appropriate. For some very special advanced motor tasks related to sports activities such as those in artistic/rhythmic gymnastics, in which large acquisition volumes are required and fast jumps and rotations are performed, the GOALS system allows configurations that can employ IR cameras with a resolution of 1.7 Mpix at 360 fps or even up to 4.1 MPix at 180 fps in an arrangement that can easily reach 100 or even more IR TVCs (**Figure 1**).

**Figure 1.** A general schematic configuration of GOALS system.

For posture evaluation (six IR TVCs at 0.3 Mpix resolution), the usual acquisition volume (i.e. the physical calibrated volume of the room, inside which the subject can be measured with known accuracy and precision) is in general somewhat like 3‐m wide by 3‐m deep by 2‐m high. With such a configuration, the usual final mean 3D stereo‐photogrammetric error is limited to a range of 0.3–0.4 mm throughout the entire working volume. If higher resolution IR TVCs are used, the 3D stereo‐photogrammetric error is even lower. The whole calibration phase takes less than 5 min. This calibration step is needed only when the cameras are initially installed or when they are moved to a new position. When the installation is fixed in a research laboratory, the calibration is performed only occasionally to maintain an accurate calibration level.
