Three-dimensional manual contact force evaluation of graded perpendicular push force delivery by second-year...

The purpose of this study was to investigate a quantitative biomechanical evaluation method for contact forces exerted during a manual examination and treatment technique used in a learning environment. The evaluation was based on three-dimensional (3D) force component data.

A hand-/palm-held computerized 3D force component measuring system was used during a simple feedback experiment involving 20 second-year university students of physiotherapy who delivered 5 sets of graded perpendicular manual push forces on the sensor part of the system, which was placed on the padded surface of an examination/treatment table. In an effect study with a multiple time-series design, a randomly chosen subgroup of subjects received concurrent visual 3D kinetic/dynamic force-time feedback.

The students delivered graded perpendicular forces with good intrasubject consistency (intraclass correlation coefficient [3, 1]: mean, 0.80; range, 0.76-0.88) but with poor intersubject consistency (intraclass correlation coefficient [2, 1]: mean, 0.38; range, 0.15-0.74). A temporary performance improvement in forward-backward force direction deviations from the perpendicular in the subgroup given feedback indicates that students are sensitive to feedback training.

An evaluation tool using 3D contact force component measurement enables the assessment of the overall magnitude of the manual contact force as well as its directional aspect. Compared with existing evaluations based on 1-dimensional force components, this 3D system allows for a more complete and, at the same time, more specific quantitative evaluation of the manual contact forces. Three-dimensional dynamic/kinetic augmented feedback has the additional potential of helping students and practitioners to improve their palpation and force delivery skills.