Our recent studies have shown that the well-documented drop in muscle force and an increase in its variability with age are accompanied by more subtle changes in the control of the hand/fingers. In particular, advanced age is associated with an impaired ability to produce both high magnitudes and accurate time profiles of moments of digit forces on a hand-held object. Recent research has also shown that the control of rotational actions is associated with specialized multi-digit synergies. Based on these findings, we have formulated six hypotheses related to age-related changes in multi-digit synergies involved in rotational actions. Three experiments with elderly and young participants will study multi-digit synergies using tasks representing typical situations of everyday usage of the hand: """"""""Prismatic grasp"""""""" (drinking from a glass), """"""""lever grasp"""""""" (opening a door handle), and """"""""lid grasp"""""""" (turning a jar lid). We will analyze the variability in the performance of these tasks and also quantify multi-digit synergies involved in the gripping/pressing and rotational task components. Three experiments will study adjustments in multi-digit synergies prior to a voluntary rotation of a hand-held object, prior to a self-triggered load/torque perturbation, and in response to an unexpected perturbation. The final experiment will study effects of eight weeks of strength training on the performance of two multi-digit tasks and quantify changes in multi-digit synergies involved in the gripping and rotational task components. We will also quantify retention of the effects of training 6 months post-training. Two types of exercise will be used, one of which will specifically target intrinsic hand muscles, which have shown a greater age-related drop in force in our earlier studies. Outcome indices of experiments will be compared to performance in four clinical functional tests. The proposed studies will be unique in quantifying age-related impairments of multi-digit synergies that stabilize hand rotational actions and their relations to hand function. The last study will potentially have implications for optimization of hand exercise for elderly.
| Singh, Tarkeshwar; Ambike, Satyajit (2017) A soft-contact model for computing safety margins in human prehension. Hum Mov Sci 55:307-314 |
| Singh, Tarkeshwar; Ambike, Satyajit (2015) A soft-contact and wrench based approach to study grasp planning and execution. J Biomech 48:3961-7 |
| Park, Jaebum; Pažin, Nemanja; Friedman, Jason et al. (2014) Mechanical properties of the human hand digits: age-related differences. Clin Biomech (Bristol, Avon) 29:129-37 |
| Solnik, Stanislaw; Zatsiorsky, Vladimir M; Latash, Mark L (2014) Internal forces during static prehension: effects of age and grasp configuration. J Mot Behav 46:211-22 |
| Singh, Tarkeshwar; Zatsiorsky, Vladimir M; Latash, Mark L (2014) Prehension synergies during fatigue of a single digit: adaptations in control with referent configurations. Motor Control 18:278-96 |
| Martin, Joel R; Terekhov, Alexander V; Latash, Mark L et al. (2013) Comparison of interfinger connection matrix computation techniques. J Appl Biomech 29:525-34 |
| Ambike, Satyajit S; Paclet, Florent; Latash, Mark L et al. (2013) Grip-force modulation in multi-finger prehension during wrist flexion and extension. Exp Brain Res 227:509-22 |
| Singh, Tarkeshwar; Zatsiorsky, Vladimir M; Latash, Mark L (2013) Adaptations to fatigue of a single digit violate the principle of superposition in a multi-finger static prehension task. Exp Brain Res 225:589-602 |
| Wu, Yen-Hsun; Pazin, Nemanja; Zatsiorsky, Vladimir M et al. (2013) Improving finger coordination in young and elderly persons. Exp Brain Res 226:273-83 |
| Singh, Tarkeshwar; Zatsiorsky, Vladimir M; Latash, Mark L (2013) Contrasting effects of fatigue on multifinger coordination in young and older adults. J Appl Physiol (1985) 115:456-67 |
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