Grip force makes wrist joint position sense worse

Abstract

Background: The purpose of this study was to investigate how grip force affects wrist joint position sense.

Methods: Twenty-two healthy participants (11 men and 11 women) underwent an ipsilateral wrist joint reposition test at 2 distinct grip forces [0 and 15% of maximal voluntary isometric contraction (MVIC)] and 6 different wrist positions (pronation 24°, supination 24°, radial deviation 16°, ulnar deviation 16°, extension 32°, and flexion 32°).

Results: The findings demonstrated significantly elevated absolute error values at 15% MVIC (3.8 ± 0.3°) than at 0% MVIC grip force [3.1 ± 0.2°, t(20) = 2.303, P = 0.032].

Conclusion: These findings demonstrated that there was significantly worse proprioceptive accuracy at 15% MVIC than at 0% MVIC grip force. These results may contribute to a better comprehension of the mechanisms underlying wrist joint injuries, the development of preventative measures to lower the risk of injuries, and the best possible design of engineering or rehabilitation devices.

Keywords: grip force; joint position sense; joint reposition test; proprioception; wrist.

FIGURE 1

An electronic digital force dynamometer was used for the maximal voluntary isometric contraction test and joint position reposition tests. Inelastic metal support (A) was added to the electronic digital force dynamometer during the MVIC test. When the grip distance was 5.0 cm (touching black sponge (D), the grip strength was adjusted to 15% MVIC by turning the knob (C) to adjust the spring (B).

FIGURE 2

The wrist joint reposition measurements were taken using a consistent body position (A) with a head mounted display (B), a screen displayed in the head mounted display (C), JPSS (D), a brace (E), an electronic digital force dynamometer (F) and a footswitch (G). The wrist start position (H) for radial deviation (I) and ulnar deviation (J), the start position (K) for extension (L) and flexion (M).

FIGURE 3

The individuals sat in a chair and the forearm unsupported (A), and the wrist in start position (B) for pronation (C) and supination (D).

FIGURE 4

Schema for the computer output observed during the monitoring that instructs the participants to find the target position (wrist extension as an example).

FIGURE 5

The absolute error, a measurement of the overall error in position reproduction as a function of grip force and wrist position (* = P < 0.05).

FIGURE 6

The is the variability in error over several trials. It demonstrates how precise the perform variable error ance is as a function of the grip force and wrist position (* = P < 0.05, ** = P < 0.01).

FIGURE 7

The constant error, reproduction force directionality of error as a function of sex, grip force and wrist position (* = P < 0.05, ** = P < 0.01).

FIGURE 8

A schematic illustration of the functional link between grip force and wrist joint position sense.