An implantable medical device comprising: communication circuity configured to establish a communication link and transfer data between the IMD intra-corpus and a computing device extra-corpus; accelerometer circuitry configured to generate a plurality of signals including a sagittal axis signal, a vertical axis signal and a transverse axis signal; and characterized by processing circuitry configured to: acquire first timestamp data and second timestamp data each one generated by the computing device and received by the IMD via the communication circuitry; calculate a patient-specific functional status parameter associated with a Sit-To-Stand test from at least one of the sagittal axis signal, the vertical axis signal and the transverse axis signal over a time segment inclusively bounded by a first time defined by the first timestamp data and a second time defined by the second timestamp data, wherein the first timestamp data is generated by the computing device based on user input indicative of a start of the Sit-To-Stand test, wherein the second timestamp data is generated by the computing device based on user input indicative of a completion of the Sit-To-Stand test, and wherein the time segment is shorter than an amount of time that the accelerometer circuitry generates the plurality of signals including the sagittal axis signal, the vertical axis signal, and the transverse axis signal; and in response to a command, activate the communication circuity to transmit the patient-specific functional status parameter from the IMD to the computing device. communication circuity configured to establish a communication link and transfer data between the IMD intra-corpus and a computing device extra-corpus; accelerometer circuitry configured to generate a plurality of signals including a sagittal axis signal, a vertical axis signal and a transverse axis signal; and characterized by processing circuitry configured to: acquire first timestamp data and second timestamp data each one generated by the computing device and received by the IMD via the communication circuitry; calculate a patient-specific functional status parameter associated with a Sit-To-Stand test from at least one of the sagittal axis signal, the vertical axis signal and the transverse axis signal over a time segment inclusively bounded by a first time defined by the first timestamp data and a second time defined by the second timestamp data, wherein the first timestamp data is generated by the computing device based on user input indicative of a start of the Sit-To-Stand test, wherein the second timestamp data is generated by the computing device based on user input indicative of a completion of the Sit-To-Stand test, and wherein the time segment is shorter than an amount of time that the accelerometer circuitry generates the plurality of signals including the sagittal axis signal, the vertical axis signal, and the transverse axis signal; and in response to a command, activate the communication circuity to transmit the patient-specific functional status parameter from the IMD to the computing device. acquire first timestamp data and second timestamp data each one generated by the computing device and received by the IMD via the communication circuitry; calculate a patient-specific functional status parameter associated with a Sit-To-Stand test from at least one of the sagittal axis signal, the vertical axis signal and the transverse axis signal over a time segment inclusively bounded by a first time defined by the first timestamp data and a second time defined by the second timestamp data, wherein the first timestamp data is generated by the computing device based on user input indicative of a start of the Sit-To-Stand test, wherein the second timestamp data is generated by the computing device based on user input indicative of a completion of the Sit-To-Stand test, and wherein the time segment is shorter than an amount of time that the accelerometer circuitry generates the plurality of signals including the sagittal axis signal, the vertical axis signal, and the transverse axis signal; and in response to a command, activate the communication circuity to transmit the patient-specific functional status parameter from the IMD to the computing device.