Purpose:
The goals of the study were: a) to compare the way that two types of active video games (AVG) influenced physical effort and motivation in young adults; b) to compare direct and indirect instruments and use an indirect instrument (heart rate analysis) as a practical tool to verify physical effort in AVGs

Methods:
Methods. Initially, 16 healthy but physically inactive young adult males with no AVGs experience took part in the randomized control trial. After the baseline assessments of blood pressure (BP), heart rate (HR), and aerobic capacity (AE), the participants were randomized into two groups: structured AVG (n = 6) and unstructured AVG (n = 7) (3 dropouts). They played 3 sessions a week, during 6 weeks. Direct and indirect metabolic measurements were made. To compare direct and indirect AE, Student t-test was used for related samples. Changes (group × time) in HR, perceived exertion (PE), calculated energy expenditure (EE), calculated metabolic equivalent (MET), and motivation (points) were assessed with the two-way analysis of variance

Results:
There were no differences between direct and indirect AE (36.0 ± 5.2 vs 33.9 ± 6.0 ml/kg/min: unstructured; 39.0 ± 5.9 vs 37.7 ± 5.9 ml/kg/min; p > 0.05). No differences were observed in maximal HR, PE, or motivation (p > 0.05). Statistically significant differences referred to average HR, MET, and EE over the sessions (p < 0.05). HR and EE values were higher in structured than in unstructured AVGs

Conclusions:
HR and EE responses of structured AVGs turned out higher than those of unstructured AVGs, and the measurements proved efficient to analyse physical effort in AVGs in a long-term perspective