Laparoscopy is a very popular surgical technique for abdominal operations. Due to the difficulties in using the laparoscopes, the surgeons need an extensive training to acquire the right locomotive skill and perform operations. Usually, the training is performed with dry boxes with simple and repetitive exercises, like the peg-board, in which a trainee uses the instruments to move sequentially a set of rubber O rings positioned inside pegs. However, even if the dry box is a good method to train the dexterity of a trainee, it does not include the mental stress, that could be significant during the operation in the actual Operating Room (OR). In this paper we present the comparison results during a peg-board training without and with induced mental stress. In particular, the stress has been introduced by a proposed protocol adaptively setting a countdown with noisy alarm for the last 60s of the exercise. We compared the results by a biomechanical analysis using surface Electromyography, showing that the induced stress situation revealed a significant larger activation of the arms and shoulders muscles.