A monitoring device (10) for monitoring movement characteristics of an item with which the monitoring device is associated, the monitoring device comprising: a transducer (15) operable to generate an electrical signal in response to movement of the item; an electrical store (18) operable to store energy on receipt of an electrical signal from the transducer (15); a radio-frequency identification device (12, 13, 14) having a data recorder (14) operable to record data on receipt of an electrical signal from the transducer (15), and a radio-frequency signal transmitter (12,13) operable to transmit a radio-frequency signal indicative of data recorded by said data recorder; and an electrical signal splitter operable to split an electrical signal generated by the transducer into a first portion and a second portion, and to provide said first portion to said electrical store and said second portion to said radio-frequency identification device.