The purpose of this study was to investigate the incidence of imposed physical constraints on the performance of students in sight-singing. Participants (N = 15) sang four melodies according to four different condition: (i) free movement, (ii) no movement, (iii) movements which reflect the melodic contour, and (iv) movements linked to metrical structure. The performances were evaluated by eight experts in five categories: (i) global assessment, (ii) rhythm, (iii) attuning, (iv) fidelity and (v) expression. We investigated the relationship between movement conditions and the variables assessed by the panel. The results showed that the movement associated with the metrical structure, considered spontaneous and not restrictive, seems to improve the performances, especially concerning to timing aspects, such as rhythm. The bodily restrictive conditions - no movement and melodic contour movement - showed the lowest scores in all tested categories. However, the interaction between factors point out that restriction would be more detrimental to certain components of the task than others.