Timing phases of the sit-to-walk movement: validity of a clinical test.

The sit-to-walk (STW) movement is a functional task that challenges balance and co-ordination. There is a paucity of literature investigating the phases of this movement and its significance in a clinical rehabilitation context. Measuring phases of this movement may provide clinically applicable data for screening subjects for mobility problems and evaluating interventions. Fifty-six subjects from three groups; young (<65 years old), elderly (>65 years old) and elderly at risk of falling (EARF), performed the STW movement freely from a chair. Switches placed on the backrest, chair seat and two on the floor identified the times of movement events: onset, seat-off, swing-off and stance-off. These events defined three phases: flexion, extension and stance. Timing of events and phase duration data derived from this switch system were correlated with those taken from a three-dimensional motion analysis system. All switch events closely matched the motion analysis events with ICC (model 2.1) scores ranging from 0.93 to 1.00. Duration of all STW phases were statistically longer in the EARF group compared to both unimpaired groups (p<0.05). Data from the four switch configuration demonstrated excellent concurrent validity when associated with data from a three-dimensional motion analysis system in identifying the phases of STW. Measurement of the phases of the STW task has potential in screening those at risk of falling and informing care strategies to prevent falls.