This collection includes data sets of one-dimensional ultrasound raw RF data (A-Scans) acquired from the biceps brachii muscles of 21 healthy volunteers. The annotation was performed by labeling the first 10 seconds of each data set as belonging to a relaxed muscle state and the last 10 seconds of each data set as belonging to a fatigue muscle states. Each line of the ARFF file contains an A-Scan consisting of 2048amplitude values, an annotation (whether this A-Scan belongs to a fatigue muscle state (1) or not (0)), a timestamp, the arm the signals were obtained from, the ID of the subject, the ID of the data set, the gender of the subject and the chosen lifted weight (2.5. kg, 5.0 kg or 7.5 kg).