Updated: May 20, 2026

Measurement of Spatial Stability in Precision Grip
Published on: June 4, 2020
1Department of Industrial and Manufacturing Engineering, University of Wisconsin-Milwaukee, 3200 North Cramer Street, Milwaukee, WI 53211, USA. seon@uwm.edu
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This study explored how object surfaces affect hand function test results. Researchers used the Box and Block Test (BBT) with wooden, rubber-covered, and paper-covered blocks. Thirteen adults performed the test with each block type. The BBT scores and movement times were compared across the three surfaces. Rubber blocks led to an 8% increase in BBT scores compared to wood or paper. This improvement was mainly due to faster contact to lift-off times. Other movement phases showed no significant differences. The findings suggest that surface friction influences grip efficiency. Therapists should consider object surfaces when interpreting test results. Redesigning objects with high-friction surfaces may help improve grip function in daily tasks.
Area of Science:
Background:
It was already known that grip strength and dexterity are commonly measured using standardized tools. However, no prior work had resolved how surface texture might influence test outcomes. This gap motivated researchers to explore if object surfaces affect performance in the Box and Block Test. The BBT is a widely used clinical tool for evaluating hand function. Prior research has shown that surface friction can influence grip mechanics. But the specific impact on timed tasks remains unclear. This uncertainty drove the need for a controlled study. By isolating surface variables, the researchers aimed to clarify their role in hand function assessments.
Purpose Of The Study:
The aim was to determine if object surfaces influence BBT scores. The researchers focused on three surface types: wooden, rubber-covered, and paper-covered blocks. They hypothesized that surface friction might alter movement times. The study sought to quantify differences in performance across these surfaces. The motivation stemmed from clinical observations of variable grip challenges. By controlling for surface effects, therapists could better interpret test results. The study also aimed to identify which movement phases are most affected. This would help in designing more accurate assessments and interventions.
Rubber surfaces increased BBT scores by 8% compared to wood or paper due to faster contact to lift-off times.
Contact to lift-off showed the greatest difference, with rubber reducing time needed to lift the block.
This phase involves initial grip formation, and surface friction directly influences how quickly a block can be lifted.
Higher friction from rubber surfaces improved grip efficiency, leading to faster movement times and higher BBT scores.
Thirteen adults performed the BBT with three different block types to assess surface effects.
Main Methods:
Thirteen adults participated in the study. Each performed the BBT using three different block types. The blocks varied in surface texture: wood, rubber, and paper. The researchers recorded BBT scores and movement times for seven phases. These phases included finger closing and contact to lift-off. They also measured transport before and after a barrier. Release, return, and reach were also timed. The data were compared across the three surface types to identify patterns.
Main Results:
The mean BBT score was 8% higher for rubber blocks than for paper or wooden ones. This difference was statistically significant (p<0.01). The contact to lift-off phase showed the most pronounced effect. Rubber surfaces reduced the time needed to lift the block. Other movement phases showed no significant differences. The overall time for the BBT was shorter with rubber blocks. These findings suggest that surface friction affects grip efficiency. The results support the idea that object surfaces influence hand function assessments.
Conclusions:
The authors propose that object surfaces affect BBT scores. Rubber surfaces appear to improve performance compared to wood or paper. This effect is most noticeable in the contact to lift-off phase. The findings suggest that surface friction influences grip mechanics. Therapists should consider surface effects when interpreting test results. Redesigning objects with high-friction surfaces may enhance grip function. The study does not claim that surface is the only factor. It highlights the need to control for surface in hand function assessments.
Therapists may vary grip difficulty by changing object surfaces to better assess and improve hand function.