Change search
ReferencesLink to record
Permanent link

Direct link
Independent control of human finger-tip forces at individual digits during precision lifting.
Umeå University, Faculty of Medicine, Integrative Medical Biology, Physiology.
Umeå University, Faculty of Medicine, Integrative Medical Biology, Physiology.
Umeå University, Faculty of Medicine, Integrative Medical Biology, Physiology.
1992 (English)In: Journal of Physiology, ISSN 0022-3751, E-ISSN 1469-7793, Vol. 450, 547-64 p.Article in journal (Refereed) Published
Abstract [en]

1. Subjects lifted an object with two parallel vertical grip surfaces and a low centre of gravity using the precision grip between the tips of the thumb and index finger. The friction between the object and the digits was varied independently at each digit by changing the contact surfaces between lifts. 2. With equal frictional conditions at the two grip surfaces, the finger-tip forces were about equal at the two digits, i.e. similar vertical lifting forces and grip forces were used. With different frictions, the digit touching the most slippery surface exerted less vertical lifting force than the digit in contact with the rougher surface. Thus, the safety margins against slips were similar at the two digits whether they made contact with surfaces of similar or different friction. 3. During digital nerve block, large and variable safety margins were employed, i.e. the finger-tip forces did not reflect the surface conditions. Slips occurred more frequently than under normal conditions (14% of all trials with nerve block, <5% during normal conditions), and they only occasionally elicited compensatory adjustments of the finger-tip forces and then at prolonged latencies. 4. The partitioning of the vertical lifting force between the digits was thus dependent on digital afferent inputs and resulted from active automatic regulation and not just from the mechanics of the task. 5. The safety margin employed at a particular digit was mainly determined by the frictional conditions encountered by the digit, and to a lesser degree by the surface condition at the same digit in the previous lift (anticipatory control), but was barely influenced by the surface condition at the other digit. 6. It was concluded that the finger-tip forces were independently controlled for each digit according to a 'non-slip strategy'. The findings suggest that the force distribution among the digits represents a digit-specific lower-level neural control establishing a stable grasp. This control relies on digit-specific afferent inputs and somatosensory memory information. It is apparently subordinated to a higher-level control that is related to the total vertical lifting and normal forces required by the lifting task and the relevant physical properties of the manipulated object.

Place, publisher, year, edition, pages
1992. Vol. 450, 547-64 p.
National Category
Medical and Health Sciences
URN: urn:nbn:se:umu:diva-32720PubMedID: 1432717OAI: diva2:305301
Available from: 2010-03-23 Created: 2010-03-23 Last updated: 2010-03-24Bibliographically approved

Open Access in DiVA

No full text

Other links

PubMedJournal home page

Search in DiVA

By author/editor
Edin, Benoni BWestling, GöranJohansson, Roland S
By organisation
In the same journal
Journal of Physiology
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 76 hits
ReferencesLink to record
Permanent link

Direct link