Quantification of Hand Grip Force under Dynamic Conditions

Author(s):  
Katherine R. Lehman ◽  
W. Gary Allread ◽  
P. Lawrence Wright ◽  
William S. Marras

A laboratory experiment was conducted to determine whether grip force capabilities are lower when the wrist is moved than in a static position. The purpose was to determine the wrist velocity levels and wrist postures that had the most significant effect on grip force. Maximum grip forces of five male and five female subjects were determined under both static and dynamic conditions. The dominant wrist of each subject was secured to a CYBEX II dynamometer and grip force was collected during isokinetic wrist deviations for four directions of motion (flexion to extension, extension to flexion, radial to ulnar, and ulnar to radial). Six different velocity levels were analyzed and grip forces were recorded at specific wrist positions throughout each range of movement. For flexion-extension motions, wrist positions from 45 degrees flexion to 45 degrees extension were analyzed whereas positions from 20 degrees radial deviation to 20 degrees ulnar deviation were studied for radial-ulnar activity. Isometric exertions were also performed at each desired wrist position. Results showed that, for all directions of motion, grip forces for all isokinetic conditions were significantly lower than for the isometric exertions. Lower grip forces were exhibited at extreme wrist flexion and extreme radial and ulnar positions for both static and dynamic conditions. The direction of motion was also found to affect grip strength; extension to flexion exertions produced larger grip forces than flexion to extension exertions and radial to ulnar motion showed larger grip forces than ulnar to radial deviation. Although, males produced larger grip forces than females in all exertions, significant interactions between gender and velocity were noted.

2014 ◽  
Vol 40 (5) ◽  
pp. 450-457 ◽  
Author(s):  
B. M. Saltzman ◽  
J. M. Frank ◽  
W. Slikker ◽  
J. J. Fernandez ◽  
M. S. Cohen ◽  
...  

We conducted a systematic review of studies reporting clinical outcomes after proximal row carpectomy or to four-corner arthrodesis for scaphoid non-union advanced collapse or scapholunate advanced collapse arthritis. Seven studies (Levels I–III; 240 patients, 242 wrists) were evaluated. Significantly different post-operative values were as follows for four-corner arthrodesis versus proximal row carpectomy groups: wrist extension, 39 (SD 11º) versus 43 (SD 11º); wrist flexion, 32 (SD 10º) versus 36 (SD 11º); flexion-extension arc, 62 (SD 14º) versus 75 (SD 10º); radial deviation, 14 (SD 5º) versus 10 (SD 5º); hand grip strength as a percentage of contralateral side, 74% (SD 13) versus 67% (SD 16); overall complication rate, 29% versus 14%. The most common post-operative complications were non-union (grouped incidence, 7%) after four-corner arthrodesis and synovitis and clinically significant oedema (3.1%) after proximal row carpectomy. Radial deviation and post-operative hand grip strength (as a percentage of the contralateral side) were significantly better after four-corner arthrodesis. Four-corner arthrodesis gave significantly greater post-operative radial deviation and grip strength as a percentage of the opposite side. Wrist flexion, extension, and the flexion-extension arc were better after proximal row carpectomy, which also had a lower overall complication rate. Level of evidence: Level III (Level I-III studies), Systematic Review. Therapeutic.


Author(s):  
Khaled W. Al-Eisawi ◽  
Carter J. Kerk ◽  
Jerome J. Congleton

The objective of this study is to evaluate the assumption in biomechanical models that wrist strength does not limit manual exertion capability. An experiment was designed and run on right-handed males to test isometric elbow flexion strength at two included elbow angles: 90° and 135° and in two forearm positions: supinated and mid between supination and pronation. Isometric wrist flexion strength was also measured at the same elbow angles and at two wrist positions in the flexion/extension plane: neutral and 45° extended. Isometric wrist radial deviation strength was measured at the same two elbow angles and at two wrist positions in the radial/ulnar deviation plane: neutral and 30° ulnarly deviated. An equation was developed to calculate the theoretical minimum wrist strength limits for which wrist strength does not limit maximal moments about the elbow. These calculated limits were compared to the corresponding measured wrist strength moments. In general, wrist strength was found to be non-limiting, but in some specific circumstances, it can be limiting. Among the posture/exertion combinations tested, only wrist flexion strength in the extended wrist posture was found to be limiting. There was some evidence that strong-wrist people show less wrist strength limitations than weak-wrist people in some postures. It was also found that the neutral wrist posture is not associated with the highest wrist strength.


Hand ◽  
2017 ◽  
Vol 13 (4) ◽  
pp. 441-447 ◽  
Author(s):  
Pavlos Bobos ◽  
Emily A. Lalone ◽  
Ruby Grewal ◽  
Joy C. MacDermid

Background: The relationship of routinely measured grip and motion measures may be related to hand dexterity. This has not yet been thoroughly examined following a distal radius fracture (DRF). The purpose of this study was to investigate if impairments in range of motion (ROM) and grip strength predict hand dexterity 6 months following a DRF. Methods: Patients with DRFs were recruited from a specialized hand clinic. Hand grip was assessed with a J-Tech dynamometer; ROM was measured using standard landmarks and a manual goniometer. Multiple regression analyses were performed to identify whether potential predictors (grip, ROM, age, hand dominance, and sex) were associated with 3-month or 6-month outcomes in large- and small-object subtests of the NK dexterity test in the affected hand. Results: Age, sex, and arc motion for radial-ulnar deviation were significant predictors of large-object hand dexterity explaining the 23% of the variation. For small-object hand dexterity, age and flexion-extension arc motion were significant predictors explaining 11% of the variation at 3 month after the fracture (n = 391). At 6 months post injury (n = 319), grip strength, arc motion for flexion-extension, and age were found to be significant predictors of large-object dexterity explaining 34% of the variance. For the small objects, age, grip strength, sex, and arc motion of radial-ulnar deviation explained 25% of the variation. Conclusions: Although this confirms that the impairments in ROM and grip that occur after a DRF can explain almost one-third of the variation in hand dexterity, it also suggests the need for dexterity testing to provide more accurate assessment.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11038
Author(s):  
Kaylyn E. Turcotte ◽  
Aaron M. Kociolek

Background We assessed median nerve travel and deformation concurrently to better understand the influence of occupational risk factors on carpal tunnel dynamics, including forceful chuck gripping and deviated wrist positions. Methods Fourteen healthy right-hand dominant participants performed a chuck grip in 6 experimental conditions: two relative force levels (10% and 40% of maximum voluntary effort); three wrist positions (15° radial deviation, 0° neutral, 30° ulnar deviation). Chuck grip forces were measured with a load cell while the transverse cross-section of the carpal tunnel was imaged via ultrasound at the distal wrist crease. Images of the median nerve were analyzed in ImageJ to assess cross-sectional area, circularity, width, and height as well as travel in the anterior-posterior and medial-lateral axes. Results We found a main effect of deviated wrist position on both anterior-posterior and medial-lateral travel, with the greatest nerve travel occurring in 30° ulnar deviation. There was also a significant interaction between chuck grip force and deviated wrist position on cross-sectional area. Specifically, the area decreased with 40% vs. 10% chuck grip force when the wrist was in 30° ulnar deviation; however, there were no changes in 0° neutral and 15° radial deviation. Discussion Overall, we demonstrated that forceful chuck gripping in deviated wrist positions influenced carpal tunnel dynamics, resulting in both migratory and morphological changes to the median nerve. These changes may, in turn, increase local strain and stress with adjacent structures in the carpal tunnel. Future studies mapping contact stress between structures may further elucidate injury development of work-related carpal tunnel syndrome.


Author(s):  
Jiamin Wang ◽  
Oumar Barry ◽  
Andrew J. Kurdila ◽  
Sujith Vijayan

Abstract This paper introduces a novel wearable full wrist exoskeleton designed for the alleviation of tremor in patients suffering from Parkinson’s Disease and Essential Tremor. The design introduces a structure to provide full observation of wrist kinematics as well as actuation in wrist flexion/extension and radial/ulnar deviation. To examine the feasibility of the design, the coupled dynamics of the device and the forearm is modeled via a general multibody framework. The dynamic analysis considers human motion, wrist stiffness, and tremor dynamics. The analysis of the model reveals that the identification of the wrist kinematics is indispensable for the controller design. Nonlinear regression based on the Levenberg-Marquardt algorithm has been applied to estimate the unknown parameters in a kinematic structural function designed to approximate the wrist kinematics, which leads to the construction of the control system framework. Finally, several simulation cases are demonstrated to conclude the study.


2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Shu-Chun Lee ◽  
Li-Chen Wu ◽  
Shang-Lin Chiang ◽  
Liang-Hsuan Lu ◽  
Chao-Ying Chen ◽  
...  

Background. Grip-force performance can be affected by aging, and hand-grip weakness is associated with functional limitations of dasily living. However, using an appropriate digital hand-held dynamometer with continuous hand-grip force data collection shows age-related changes in the quality of hand-grip force control may provide more valuable information for clinical diagnoses rather than merely recording instantaneous maximal hand-grip force in frail elderly adults or people with a disability. Therefore, the purpose of this study was to indicate the construct validity of the digital MicroFET3 dynamometer with Jamar values for maximal grip-force assessments in elderly and young adults and confirmed age-related changes in the maximal and the quality of grip-force performance using the MicroFET3 dynamometer in elderly people. Methods. Sixty-five healthy young (23.3±4.5 years) and 50 elderly (69.5±5.8 years) adults were recruited and asked to perform a validity test of the grip-force maximum voluntary contraction (MVC) using both the dominant and nondominant hands with a Jamar dynamometer and a MicroFET3 dynamometer. Results. A strong correlation of maximal grip-force measurements was found between the MicroFET3 dynamometer and Jamar standard dynamometer for both hands in all participants (p<0.05). Although, the results showed that a lower grip force was measured in both hands by the MicroFET3 dynamometer than with the Jamar dynamometer by 49.9%~57% (p<0.05), but confidently conversion formulae were also developed to convert MicroFET3 dynamometer values to equivalent Jamar values for both hands. Both dynamometers indicated age-related declines in the maximum grip-force performance by 36.7%~44.3% (p<0.05). We also found that the maximal hand-grip force values generated in both hand by the elderly adults were slower and more inconsistent than those of the young adults when using the MicroFET3 dynamometer. Conclusions. This study demonstrated that the digital MicroFET3 dynamometer has good validity when used to measure the maximal grip force of both hands, and conversion formulae were also developed to convert MicroFET3 dynamometer force values to Jamar values in both hands. Comparing with the Jamar dynamometer for measuring grip force, the MicroFET3 dynamometer not only indicated age-related declines in the maximum grip-force performance but also showed slower and more inconsistent maximal hand-grip strength generation by the elderly.


2018 ◽  
Vol 11 (02) ◽  
pp. 088-093 ◽  
Author(s):  
Stacy Fan ◽  
Jeremy Cepek ◽  
Caitlin Symonette ◽  
Douglas Ross ◽  
Shrikant Chinchalkar ◽  
...  

Abstract Background Grip strength and wrist range of motion (ROM) are important metrics used to evaluate hand rehabilitation and outcomes of wrist interventions. Published normative data on these metrics do not recognize the contribution of forearm rotation. This study aims to identify and quantify variations in grip strength and wrist ROM with forearm rotation in healthy young individuals. Materials and Methods Wrist ROM and grip strength were measured in 30 healthy volunteers aged 23 to 30. Participant demographics, grip strength, and wrist ROM (wrist flexion and extension, ulnar and radial deviation) at three forearm positions (full supination, neutral, and full pronation) were measured using a digital dynamometer and standard goniometers. Data analysis was conducted using a one-way repeated measure ANOVA. Forearm position values were compared using post hoc analysis. Results Grip strength in males was greatest in neutral position (males: nondominant 51.4 kg, dominant 56.1 kg) followed by supination (males: nondominant 46.6 kg, dominant 51.7 kg) and weakest in pronation (males: nondominant 40.1 kg, dominant 42.9 kg). Grip strength in females was similar between supination (nondominant: 26.1 kg, dominant: 28.5 kg) and neutral (nondominant: 27.4 kg, dominant: 29.1 kg) positions, but both were greater than in pronation (nondominant: 22.3 kg, dominant: 24.1 kg). Wrist flexion in males was significantly reduced in supination compared with neutral and pronated positions (nondominant: supination 63.1°, neutral 72.6°, pronation 73.3°; dominant: supination 62.4°, neutral 70.2°, pronation 70.3°), whereas not significant wrist flexion in females was also weaker in supination (supination 74.4°, neutral 79.9°). Wrist extension in males was greater in pronation (supination 64.6°, pronation 69.5°) whereas females showed no significant difference in any of the forearm positions. Ulnar deviation in males did not differ with forearm position, but females demonstrated greater ulnar deviation in supination on the nondominant hand (supination 44.6°, pronation 33.2°). Whereas there was no difference in radial deviation with forearm position in females, it was markedly greater in pronation versus supination on both sides in males (nondominant: supination 16.3°, pronation 24.6°; dominant: supination 15.4°, pronation 23.9°). Conclusion This study characterizes variations in grip strength and wrist ROM in three forearm positions in healthy young individuals. All measurements differed with forearm rotation and were not influenced by hand dominance. These results suggest that wrist ROM and grip strength should be evaluated in different positions of forearm rotation, rather than a fixed position. This has functional implications particularly in patients involved with specialized activities such as sports, instrument-playing, or work-related activities.


1998 ◽  
Vol 23 (3) ◽  
pp. 406-409 ◽  
Author(s):  
R. LUCHETTI ◽  
O. SORAGNI ◽  
T. FAIRPLAY

From 1990 to 1994, nine proximal row carpectomies were done through a palmar approach. With an average follow-up of 20 months, seven of the nine patients were completely painfree. Average range of wrist flexion/extension remained unchanged, and average radial/ulnar deviation increased from 25° to 46°. All the patients demonstrated an increase in grip strength in the operated hand. Four cases showed a slight reduction in articular space and subchondral sclerosis in the radiocapitate articulation, in spite of good function. Dynamic studies demonstrated no sign of radiocarpal instability. All the patients were very satisfied with the results and returned to their previous work within 2 months, on average.


Author(s):  
Na Jin Seo ◽  
Thomas J. Armstrong ◽  
Kathryn L. Dannecker

This study quantifies the effect of a simultaneous grip on wrist strength. It was hypothesized that wrist flexion strength increases with an increasing grip and wrist extension strength decreases with an increasing grip. Twelve subjects performed maximum wrist flexion and extension exertions with a different level of simultaneous grip – minimum, preferred, and maximum. Wrist flexion strength increased 34% and wrist extension strength decreased 10% from minimum to maximum grip. This shows that measure of wrist strength for assessing strength capabilities or the efficacy of hand surgeries or rehabilitation programs requires control of finger flexor activities to ensure consistent and relevant results. When opening a bottle in an outward direction (right hand thread), wrist extension strength may be significantly limited by a simultaneous grip due to muscle antagonism. When twisting a fragile or uncomfortable object, reduced finger flexor activities can limit wrist flexion strength.


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