Grip and load force coordination in cyclical isometric manipulation task is not affected by the feedback type

Author(s)

Pedao, Sabrina Tiago ^{[1, 2]} ; Barela, Jose Angelo ^{[1, 2, 3]} ; de Almeida Lima, Kaue Carvalho ^{[1, 2]} ; de Freitas, Paulo Barbosa ^{[1, 2]}

Affiliation

^[1] Cruzeiro do Sul Univ, Inst Phys Act & Sport Sci, BR-01506000 Sao Paulo - Brazil

^[2] Cruzeiro do Sul Univ, Grad Program Human Movement Sci, BR-01506000 Sao Paulo - Brazil

^[3] Sao Paulo State Univ Rio Claro, Biosci Inst, Dept Phys Educ, BR-13506900 Sao Paulo - Brazil

• Document type: Journal article
• Source: JOURNAL OF NEUROENGINEERING AND REHABILITATION; v. 10, APR 4 2013.
• Web of Science Citations: 2

Abstract

Background: The relationship between normal and tangential force components (grip force - GF and load force - LF, respectively) acting on the digits-object interface during object manipulation reveals neural mechanisms involved in movement control. Here, we examined whether the feedback type provided to the participants during exertion of LF would influence GF-LF coordination and task performance. Methods: Sixteen young (24.7 +/- 3.8 years-old) volunteers isometrically exerted continuously sinusoidal F-Z (vertical component of LF) by pulling a fixed instrumented handle up and relaxing under two feedback conditions: targeting and tracking. In targeting condition, F-Z exertion range was determined by horizontal lines representing the upper (10 N) and lower (1 N) targets, with frequency (0.77 or 1.53 Hz) dictated by a metronome. In tracking condition, a sinusoidal template set at similar frequencies and range was presented and should be superposed by the participants' exerted F-Z. Task performance was assessed by absolute errors at peaks (AE(Peak)) and valleys (AE(Valley)) and GF-LF coordination by GF-LF ratios, maximum cross-correlation coefficients (r(max)), and time lags. Results: The results revealed no effect of feedback and no feedback by frequency interaction on any variable. AE(Peak) and GF-LF ratio were higher and r(max) lower at 1.53 Hz than at 0.77 Hz. Conclusion: These findings indicate that the type of feedback does not influence task performance and GF-LF coordination. Therefore, we recommend the use of tracking tasks when assessing GF-LF coordination during isometric LF exertion in externally fixed instrumented handles because they are easier to understand and provide additional indices (e.g., RMSE) of voluntary force control. (AU)

• FAPESP's process: 10/02939-4 - Hand function in neuropathic diabetic patients: control and coordination of forces acting on the digits-object interaction in manipulation tasks
• Grantee: Paulo Barbosa de Freitas Júnior
• Support Opportunities: Regular Research Grants