Thesis (MEng) -- Stellenbosch University, 2014. / ENGLISH ABSTRACT: The Dorsiflexometer is a device designed and built for the assessment of a patient’s balance capabilities. The birth of the Dorsiflexometer is due to a serious need for physiological balance assessment equipment, capable of conducting dynamic tests in the clinical setting. This is accomplished by recording and analysing the patient’s response to sagittal plane perturbations. The Dorsiflexometer is operated from a computer software interface program. It uses the measurements from a single force plate to calculate four balance metrics’ characterising a patient’s ability to maintain balance. These balance metrics include the sway index, equilibrium score, postural stability index and radius parameter. A single and a double inverted pendulum model of the human body is derived to calculate a patient’s centre of mass movement in the sagittal plane with the measured force plate data and body parameters. Three experiments, involving 48 subjects, were conducted. The experimental tests proved the competency of the machine, the accuracy of both inverted pendulum models and the balance response of seafarers aboard an Antarctic research and supply vessel during rough sea conditions. The tests concluded that the inverted pendulum models can be used to calculate the body centre of mass displacement. The double inverted pendulum model results are more accurate compared with the single inverted pendulum model. During rough sea conditions, the body movement and postural response of seafarers are increased in order to keep themselves upright. The body is furthermore exposed to a fluctuating ground reaction force which may lead to the progression of osteoarthritis and musculoskeletal injuries. The Dorsiflexometer proved to be capable of conducting repeatable assessments and yielding accurate results which can be used to distinguish between balance capabilities. / AFRIKKANSE OPSOMMING: Die Dorsiflexometer is ’n apparaat wat die balansvermoë van pasiënte analiseer. Die masjien is ontwerp en vervaardig weens die groot behoefte aan fisiologiese balans assesserings toerusting wat dinamiese toetse in die mediese sektor kan bepaal. Dit word bereik deur pasiënte se liggaamsreaksie in die sagittale vlak te meet en te assesseer. Die Dorsiflexometer is beheerbaar vanaf ’n rekenaar sagteware koppelvlak program. Die masjien maak gebruik van ’n enkele kragplaat om pasiënte se balans statistieke te meet. Hierdie balans statistieke wat die pasiënte se balans vermoë beskryf en karakteriseer behels die sogenaamde: swaai indeks, balans telling, posturale stabiliteit indeks en die radius parameter. ’n Enkel en dubbel inverse slinger model van die liggaam is afgelei. Hierdie modelle maak gebruik van ’n pasiënt se kragplaat metings en sy liggaamlike parameters om die swaartepunt tydens beweging te bereken. Drie eksperimente, waarin 48 persone betrokke was, is gedoen. Die eksperimente is gedoen om die apparaat se bevoegdheid te bewys, die akkuraatheid van altwee inverse slinger modelle te toets en verder die balans van seevaarders op die Antarktiese navorsings en toevoer skip tydens rowwe see toestande te analiseer. Die toetse het bewys dat die inverse modelle gebruik kan word om die liggaam se swaartepunt te bereken. Die dubbel inverse slinger model resultate is wel akkurater as die enkel slinger model. Daar is bevind dat seevaarders van meer liggaamsbeweging en posturale reaksies gebruik moet maak om orent te bly tydens rowwe seetoestande. Verder word hul liggame blootgestel aan ’n wisselende grond reaksie krag wat kan lei tot die ontwikkeling van osteoarthritis en muskuloskeletale beserings. Die Dorsiflexometer is bewys as ’n aparaat wat wat akurate resultate lewer vir herhaalbare assesserings. Dit kan gebruik word om te onderskei tussen verskillende balans vermoëns.