Il lavoro “Comparison of two biofeedback interfaces and their effect on gym exercise quality: A chest press case study“, sviluppato in collaborazione con Technogym Spa e Sapienza Università di Roma, è stato accettato all’interno del congresso della International Ergonomics Association (Firenze, dal 26 al 30 agosto 2018).

Abstract
Information and data visualisation studies have been mainly conducted in contexts where human performance was related to safety and productivity (e.g. signal detection in air traffic control) or where user experience was connected to revenues increase (e.g. e-commerce websites page layout and pictorial representations). Nowadays the pervasive digital transformation of consumer products has spread the presence of Graphical User Interfaces (GUI) into domains where contextual characteristics may require specific (and still unavailable) ways for evaluating the interfaces. Gym equipment industry is facing this challenge by designing and introducing innovative advanced training interfaces (so called “virtual coaches”) aimed at assigning training sessions and providing guidance on optimum exercise modes. The understandability and usability of these biofeedback features (information about exercise status and guidance) can affect the inner quality of any gym workout. Therefore, we compared two different biofeedback on a ‘chest press machine’ analysing their role in defining the proper exercise execution. Fourteen participants were asked to perform a workout session in three different conditions: 1) without biofeedback; 2) with biofeedback “A” (linear pilot); 3) with biofeedback “B” (strength pilot). Availability of information for making predictions about the changes in the exercise frequency/duration is the main difference between A and B biofeedback types. Particularly, the information is provided consistently with the exercise mapping. Performance was evaluated using both objective and subjective metrics. Particularly, we recorded movements duration on both the concentric and eccentric phase (eccentric/concentric compared with the biofeedback pilot pace benchmark) and eye movements count/duration (compared with the subject ability of continuously follow the biofeedback pacer). Subjective evaluations were carried out using usability and satisfaction questionnaires. Although conducted on a small sample, results showed a tendency towards statistical significance between the interfaces. Namely, three basic highlights can be made for further investigations:

• Biofeedback GUI affects the quality of a training;
• Biofeedback allowing predictions of the exercise pace (version “B”) performs better;
• Metrics based on participants movements and their ocular behavior can be used as objective measures during assessment processes.