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1

Assessment of Hand Function Through the Coordination of Contact Forces in Manipulation Tasks

100%

Jaric S., Uygur M.

Journal of Human Kinetics

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2013

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vol. 36

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issue 1

5-160

EN

Exploration of force coordination has been one of the most often used approaches in studies of hand function. When holding and manipulating a hand-held object healthy individuals are typically able to highly coordinate the perpendicular (grip force; GF) with the tangential component of the contact force (load force; LF). The purpose of this review is to present the findings of our recent studies of GF-LF coordination. Regarding the mechanical factors affecting GF-LF coordination, our data suggest that both different hand segments and their particular skin areas could have markedly different friction properties. It also appears that the absolute, rather than relative safety margin (i.e., how much the actual GF exceeds the minimum value that prevents slipping) should be a variable of choice when assessing the applied magnitude of GF. The safety margin could also be lower in static than in free holding tasks. Regarding the involved neural factors, the data suggest that the increased frequency, rather than an increased range of a cyclic LF could have a prominent detrimental effect on the GF-LF coordination. Finally, it appears that the given instructions (e.g., 'to hold' vs. 'to pull') can prominently alter GF-LF coordination in otherwise identical manipulation tasks. Conversely, the effects of handedness could be relatively week showing only slight lagging of GF in the non-dominant, but not in the dominant hand. The presented findings reveal important aspects of hand function as seen through GF-LF coordination. Specifically, the use of specific hand areas for grasping, calculation of particular safety margins, the role of LF frequency (but not of LF range) and the effects of given instructions should be all taken into account when conducting future studies of manipulation tasks, standardizing their procedures and designing routine clinical tests of hand function.

2

The Relationship Between Foot and Pelvic Alignment While Standing

86%

Khamis S., Dar G., Peretz C., Yizhar Z.

Journal of Human Kinetics

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2015

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vol. 46

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issue 1

85-97

EN

A normal motion and segmental interrelationship has been determined as a significant factor in normal function. Yet, the relationship between distal segments and pelvic alignment needs further investigation. The aim of this study was to investigate the interrelationship between distal and proximal lower extremity segments while standing and during induced feet hyperpronation. Changes in alignment of the pelvis and lower extremities were measured at a gait laboratory using the VICON 612 computerized motion analysis system. Thirty-five healthy volunteer subjects were recruited. Four randomized repeated-measure standing modes were used: standing directly on the floor and then on three wedges angled at 10°, 15° and 20° to induce bilateral hyperpronation for 20 seconds. A significant (p<0.05) bi-variate relationship was found between the anterior pelvic tilt and thigh internal rotation, in all four standing positions (.41≤r≤.46, in all p<0.014). A combined effect of rotational alignment between segments and the cumulative effect of foot hyperpronation on pelvic tilt revealed that only the shank significantly affected pelvic alignment, acting as a mediator between a foot and a thigh with the thigh having a crude significant effect on the pelvis. When internal rotation of the shank occurs, calcaneal eversion couples with thigh internal rotation and anterior pelvic tilt. It can be concluded that in response to induced hyperpronation, the shank is a pivotal segment in postural adjustment.

3

Modal analysis of laminated “CAS” and “CUS” box-beams

81%

Gawryluk J., Bocheński M., Teter A., Gawryluk J., Bocheński M., Teter A.

Archive of Mechanical Engineering

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2017

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vol. 64

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issue 4

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2 Journal of Human Kinetics

1 Archive of Mechanical Engineering

1 2017

1 2015

1 2013

1 Bocheński M.

1 Dar G.

1 Gawryluk J.

1 Jaric S.

1 Khamis S.

1 Peretz C.

1 Teter A.

1 Uygur M.

1 Yizhar Z.

Assessment of Hand Function Through the Coordination of Contact Forces in Manipulation Tasks

The Relationship Between Foot and Pelvic Alignment While Standing

Modal analysis of laminated “CAS” and “CUS” box-beams