the computer 12 that the user 39 s foot has rested on the circle the pressure detectors may be calibrated as weight measuring devices so that a read out of the user 39 s weight can be given on demand say at the beginning and end of a session in use the user will stand on the mat 11 before the screen 21 and after warming up engage in any of a number of possible exercises and or game routines the reaction display 10 may be used on its own in simple reaction mode touching lit up targets in turn in a rapid response and also in a mode where recognition of a variable say of at least one of colour and shape or some exercise of thought is required further reaching for targets may be combined with stepping on selected circles on the mat requiring a further level of limb eye coordination the mat may optionally be in vibrating mode or non vibrating mode as desired the screen 21 may optionally be used to play video games or mental contests which may if desired involve a physical response e g alternate answers may be displayed on or in relation to targets selection of the correct answer being by touching the correct target possible exercises include simply pressing the screen as quickly as possible as in the known batak trade mark exerciser to press the target diametrically opposite one indicated on the screen 21 to press the colour indicated.