Acquisition Protocol

The seventh Ninapro database is described in the paper: "Agamemnon Krasoulis, Iris Kyranou, Mustapha Suphi Erden, Kianoush Nazarpour & Sethu Vijayakumar. Improved prosthetic hand control with concurrent use of myoelectric and inertial measurements. Journal of NeuroEngineering and Rehabilitation, 2017" ( Please cite this paper for any work related to this database.

More information about the protocol can be found in the original paper: "Manfredo Atzori, Arjan Gijsberts, Claudio Castellini, Barbara Caputo, Anne-Gabrielle Mittaz Hager, Simone Elsig, Giorgio Giatsidis, Franco Bassetto & Henning Müller. Electromyography data for non-invasive naturally-controlled robotic hand prostheses. Scientific Data, 2014" (

The experiment is divided in two exercises:

1. Basic movements of the fingers and of the wrist

2. Grasping and functional movements

In the two exercises, the subjects have to repeat several movements represented by movies that are shown on the screen of a computer monitor; the kinematic information is recorded with a dataglove (cyberglove 2, 18-DOF model).

The muscular activity is gathered using 12 active double–differential wireless electrodes from a Delsys Trigno IM Wireless EMG system. The sensors comprise EMG electrodes and 9-axes inertial measurement units (IMUs). The sensors are positioned as shown in the figure: eight sensors are equally spaced around the forearm in correspondence to the radio humeral joint; two sensors are placed on the main activity spots of the flexor digitorum and of the extensor digitorum as described in; two sensors are placed on the main activity spots of the biceps and of the triceps. The described locations have been chosen in order to combine a dense sampling approach with a precise anatomical positioning strategy.

The sensors were fixed on the forearm using their standard adhesive bands. Moreover, a hypoallergenic elastic latex–free band was placed around the sensors to keep them fixed during the acquisition.

The sEMG signals are sampled at a rate of 2 kHz.

Twenty able-bodied (Subjects 1-20) and two right-hand transradial amputee participants (Subjects 21-22) are included in the dataset. During the acquisition, the subjects were asked to repeat the movements with the right hand (phantom limb in the case of amputees). Each movement repetition lasted 5 seconds and was followed by 3 seconds of rest. The protocol includes 6 repetitions of 40 different movements (plus rest). One of the amputee subjects (Subject 21) did not perform the final two (functional) movements of Exercise 2; therefore, the number of classes associated with this subject is 38. The movements were selected from the hand taxonomy as well as from hand robotics literature.

Data Sets

For each exercise, for each subject, the database contains one matlab file with synchronized variables.

The variables included in the matlab files are:

- subject: subject number

- exercise: exercise number

- acc (36 columns): three-axes accelerometers of the 12 sensors

- gyro (36 columns): three-axes gyroscopes of the 12 sensors

- mag (36 columns): three-axes magnetometers of the 12 sensors

- emg (12 columns): sEMG signal of the 12 sensors

- glove (22 columns): uncalibrated signal from the 22 sensors of the cyberglove

- stimulus (1 column): the movement repeated by the subject.

- restimulus (1 column): again the movement repeated by the subject. In this case the duration of the movement label is refined a-posteriori in order to correspond to the real movement

- repetition (1 column): repetition of the stimulus

- rerepetition (1 column): repetition of restimulus

The cyberglove signal corresponds to data from the cyberglove sensors located as shown in the following picture; "n/a" corresponds to not available sensors, since an 18-DOF model was used. Prior to each experiment, the data glove was calibrated to the specific subject using the "quick calibration" procedure provided by the manufacturer.