  Recurrent or sustained awkward body postures are among the most frequently
cited risk factors to the development of work-related musculoskeletal disorders
(MSDs). To prevent workers from adopting harmful configurations but also to
guide them toward more ergonomic ones, wearable haptic devices may be the ideal
solution. In this paper, a vibrotactile unit, called ErgoTac, and a
slide-and-squeeze unit, called CUFF, were evaluated in a limbs postural
correction setting. Their capability of providing single-joint (shoulder or
knee) and multi-joint (shoulder and knee at once) guidance was compared in
twelve healthy subjects, using quantitative task-related metrics and subjective
quantitative evaluation. An integrated environment was also built to ease
communication and data sharing between the involved sensor and feedback
systems. Results show good acceptability and intuitiveness for both devices.
ErgoTac appeared as the suitable feedback device for the shoulder, while the
CUFF may be the effective solution for the knee. This comparative study,
although preliminary, was propaedeutic to the potential integration of the two
devices for effective whole-body postural corrections, with the aim to develop
a feedback and assistive apparatus to increase workers' awareness about risky
working conditions and therefore to prevent MSDs.
