A database system for processing athletic performance data, the database system comprising: a data acquisition subsystem configured to generate and transmit a first signal; and a processor subsystem in communication with the data acquisition subsystem, wherein the processor subsystem is configured to receive the first signal and process the first signal to obtain a first parameter signal that is representative of a physiological parameter or a performance parameter of a subject and to transmit the first parameter signal to a database, the database being configured to receive and store the first parameter signal, wherein the database is configured to receive and store a second parameter signal representative of a physiological parameter or a performance parameter of a second subject; wherein the database system further comprises a control-data processing subsystem configured to compare the first parameter signal with the second parameter signal to determine similarities between the parameter information contained in the first parameter signal and the second parameter signal, and wherein the database is configured to store the first parameter signal in association with demographic information of the subject and historical athletic performance data of the subject; and characterized in that the control-data processing subsystem is configured to determine if the first parameter signal and second parameter signal share a common attribute, wherein the attribute is an athletic performance level or a type of sport, and wherein, if it is determined that the first and second parameter signals share the attribute, the control-data processing subsystem is configured to store a database subset that comprises the first and second parameter signals. a data acquisition subsystem configured to generate and transmit a first signal; and a processor subsystem in communication with the data acquisition subsystem, wherein the processor subsystem is configured to receive the first signal and process the first signal to obtain a first parameter signal that is representative of a physiological parameter or a performance parameter of a subject and to transmit the first parameter signal to a database, the database being configured to receive and store the first parameter signal, wherein the database is configured to receive and store a second parameter signal representative of a physiological parameter or a performance parameter of a second subject; wherein the database system further comprises a control-data processing subsystem configured to compare the first parameter signal with the second parameter signal to determine similarities between the parameter information contained in the first parameter signal and the second parameter signal, and wherein the database is configured to store the first parameter signal in association with demographic information of the subject and historical athletic performance data of the subject; and characterized in that the control-data processing subsystem is configured to determine if the first parameter signal and second parameter signal share a common attribute, wherein the attribute is an athletic performance level or a type of sport, and wherein, if it is determined that the first and second parameter signals share the attribute, the control-data processing subsystem is configured to store a database subset that comprises the first and second parameter signals.