Quantitative analysis of surgeons' motor variability during the surgical practice is still scarce. Therefore, a framework for the analysis of surgeon upper-body postural variability during laparoscopic procedures was developed. 3D kinematics analysis gave us information regarding the head posture adopted by the surgeons with respect to the trunk and how this varies during surgical training activities. Furthermore, surgeon's upper-body joint variability was quantified using the framework of the Uncontrolled Manifold hypothesis, allowing to separate the combination of joint angles that were equally able to stabilize head mean posture on sagittal plane for those solutions that were destabilized head mean posture. The results showed that the underlying framework was able to quantify surgeons' motor variability, providing inspiration for new human-machine interaction designs, as well as more targeted ergonomics assessments.

Eye-tracking research has allowed the characterisation of gaze behaviours in some racket sports (e.g., tennis, badminton), both in controlled laboratory settings and in real-world scenarios. However, there are no studies about visual patterns displayed by athletes in padel. Method: The aim of this exploratory case study was to address the visual behaviours of eight young expert padel athletes when playing match games on a padel court. Specifically, their gaze behaviours were examined with an in situ approach while returned trays/smashes, serves, and volleys were performed by their counterparts. Gaze patterns were registered with an SMI Eye Tracking Glasses 2 Wireless. Results: The participants’ gaze was mainly focused on the ball-flight trajectory and on the upper body of the opponents because they were the two visual locations with a larger number of fixations and longer fixation time. No differences were found in these variables for each type of visual location when the three return situations were compared, or independently of them. Conclusions: Padel players displayed a similar gaze behaviour during different representative return situations. This visual pattern was characterised by fixating at the ball and some opponents’ upper kinematics (head, shoulders, trunk, and the region of arm–hand–racket) to perform real interceptive actions while playing against them on a padel court.