A chair with a platform setup to measure the forces under each thigh when sitting, rising from a chair and sitting down

Abstract

This paper describes the design, technical characteristics and first results of an adjustable instrumented chair with a sitting surface that records the forces under each thigh. The seat includes a force platform assembly suitable for measuring the magnitude, position and direction of the force applied to each thigh while sitting or rising from the chair. The natural frequency of the chair fixed to the floor was found to be 14.0 +/- 2 Hz with an estimated damping of xi = 0.20. Static tests showed that the maximal errors were 2% of the full-scale output (726 N vertically, 164 N horizontally) for both vertical and horizontal forces. The root mean square error of the center of pressure location was estimated as 5 mm. Preliminary data on the net joint moment at the hips of one healthy subject computed with and without consideration for the forces under the thighs revealed significant amplitude differences. In conclusion, the results indicate that the characteristics of the instrumented chair are acceptable and the chair can be used to assess the biomechanics of sitting and sit-to-stand and stand-to-sit tasks in various subject populations.

Performance of elite seated discus throwers in F30s classes

“…contact external forces and moments) could be collected. 30 All combined, these analyses will provide a better understanding of the relationship between performance and design of the throwing frame.…”

“…feet, knees, buttocks, hips and arm rest). 30 In addition, an experimental study would aim at correlating a given characteristic (e.g. feet positions, point of contact and type of attachment) with parameters of performance (e.g.…”

Development and validation of an innovative tool for the assessment of biomechanical strategies: The Timed “Up and Go” – Assessment of Biomechanical Strategies (TUG-ABS) for individuals with stroke

“…An adjustable instrumented chair with 4 AMTI strain gauge transducers (MC3A-3-250, AMTI, Newton, MA, USA) was also used to record orthogonal forces under each thigh (49). The (28) with the values of adequate modified kappa-like index regarding the number of participant experts was also employed.…”

Performance of elite seated discus throwers in F30s classes

“…contact external forces and moments) confounders could be collected. 43 Furthermore, future studies focusing on optimal placements of artificial legs of discus throwers with single or double amputation will be particularly interesting ( Figure 2). Such information will be valuable to better understand the actual contribution of lower limb placements in the performance.…”