FOOT PLACEMENT EFFECTS THE PROPORTION OF MAXIMAL KNEE EXTENSOR MOMENT PRODUCED IN SIT TO STAND AND STAND TO SIT ACTIVITIES

The sit-to-stand task is a fundamental activity of daily living and a key component of the functional independence. The aim of the study was to identify the effects of foot placement on generated moments during sit-to-stand and stand-to-sit activities. Two healthy adults (1M, 1F) volunteered for the study. Isokinetic measurements were conducted by use of Cybex? dynamometer. Sit-to-stand performance has been analysed using CODA?mpx30. AMTI? has been used to measure the force and moment components of foot. The data from sit-to-stand activity has been compared with concentric peak knee extensor moments and the data from stand-to-sit task has been compared with eccentric peak extensor moments. Peak knee extensor moments from Cybex? represent maximal achievable force. Knee moments recorded by CODA? has been converted to a proportion of this maximum. Participants had greater peak knee extensor moments in dominant side comparing to non-dominant side in symmetrical and left foot forward positions during sit-to-stand task. When right foot placed forward non-dominant side had greater peak knee extensor moments than dominant side. Similar to findings from sit-to-stand tasks, participants had greater peak knee moments in dominant side during feet symmetrical and left foot forward positions during stand-to-sit task performance. This study confirms the generation of a knee extensor moment as a key component for an appropriate sit-to-stand performance. During sit-to-stand, right and left sides produce different amount of torque and before a sit-to-stand, positioning the stronger side forward results in an increase in peak knee extensor moment on the weaker side.