Enslaving effects in multi-finger force production

  title={Enslaving effects in multi-finger force production},
  author={Vladimir M. Zatsiorsky and Zong-Ming Li and Mark L. Latash},
  journal={Experimental Brain Research},
Abstract. When a person produces isometric force with one, two, or three fingers, the other fingers of the hand also produce a certain force. Enslaving is the involuntary force production by fingers not explicitly involved in a force-production task. This study explored the enslaving effects (EE) in multi-finger tasks in which the contributions of the flexor digitorum profundus (FDP), flexor digitorum superficialis (FDS), and intrinsic muscles (INT) were manipulated. A new experimental… 
Timing and extent of finger force enslaving during a dynamic force task cannot be explained by EMG activity patterns
The results suggest that mechanical connections between muscle-tendon structures were (at least partly) responsible for the observed increase in force enslaving during index finger flexion.
The effect of enslaving on perception of finger forces
The results show that there is a tendency to match the absolute magnitude of the total force during ipsilateral finger force-matching tasks, likely related to enslaving effects and provide evidence that all finger forces are sensed, thus resulting in perception of theabsolute magnitude of total finger force.
Motion enslaving among multiple fingers of the human hand.
The results suggest that there exist relatively large enslaving effects among the compartments of the flexor digitorum profundus, and functional independence of fingers in daily activities is likely enhanced through synergistic activities of multiple muscles, including flexors and extensor.
A Study on Multiple Reationship between Finger Force and Neural Command
The results confirmed that the finger forces were generated without the neural commands up to 20% of their maximal forces as the enslaving effect and the force deficit effect increased with the number of fingers involved.
Interaction between Finger Force and Neural Command in Multi-Finger Force Production
A mathematical model proposed in this paper based on the experimental results could explicitly describe the two effects of finger interaction by representing the relationship between the neural commands and finger forces.
Multi-finger interaction during involuntary and voluntary single finger force changes
A range of factors affecting force changes are discussed, from purely mechanical effects of finger passive lifting to neural synergic adjustments of commands to individual fingers, to a recently suggested scheme that merges the equilibrium-point hypothesis (control with referent configurations) with the idea of hierarchical synergic control of multi-element systems.
Voluntary activation of the different compartments of the flexor digitorum profundus.
The results indicate that maximal VA is similar for all four compartments of FDP when force production by the other fingers is unconstrained, and when altered mechanical connections between the compartments decrease voluntary force output there is little difference in neural drive.


Coordinated force production in multi-finger tasks: finger interaction and neural network modeling
A neural network model that accounts for all the three effects of involuntary force production by individual fingers during tasks when (an)other finger(s) of the hand generated maximal voluntary pressing force in isometric conditions suggests that no direct correspondence exists between neural command and finger force.
Force sharing among fingers as a model of the redundancy problem
It was found that individual finger forces were smaller in multifinger MVC tasks than in single-finger tasks, and a hypothesis is suggested that force distribution among fingers may be organized so as to minimize unnecessary rotational moment with respect to the functional longitudinal axis of the hand.
Limited independent flexion of the thumb and fingers in human subjects.
It is not possible to direct a sufficiently focal motor command to flex selectively the distal joint of the fingers and thumb when forces exceeding 2.5% MVC are generated and movement of adjacent digits may also involve ‘in‐series’ mechanical links between adjacent components of FDP.
Muscular production of individuated finger movements: the roles of extrinsic finger muscles
  • MH Schieber
  • Biology, Psychology
    The Journal of neuroscience : the official journal of the Society for Neuroscience
  • 1995
EMG activity from muscles of the forearm as trained rhesus monkeys performed flexion and extension individuated movements showed that EMG activity changes in the extrinsic finger muscles, and the thenar muscles, could account for most of the motion of both the instructed digit and noninstructed digits.
Neural and biomechanical specializations of human thumb muscles revealed by matching weights and grasping objects.
The accuracy of weight matching was used to investigate whether thumb muscles perform differently from index muscles, and the two intrinsic hand muscles (FDI and AP) were equally accurate, and significantly more accurate than FDP which was the least accurate muscle.