Finger Grip Force Research Articles

Effects of Dry Needling in Carpal Tunnel Syndrome: A Mini-review

Carpal Tunnel Syndrome (CTS) is a complicated ailment in which there is compression of the median nerve in the carpal tunnel and which can lead to pain, disrupt the range of motion, hand function, and finger grip force. Dry needling treatment is used for CTS by inserting the needle to reduce pain and lowering the tension over the nerve to improve symptoms. This review aimed to determine whether dry needling is useful in treating carpal tunnel syndrome symptoms. Studies published between 2000 and 2021 were identified by searching PubMed, Google Scholar, and Springer. Studies identified by the electronic search were screened against a set of predetermined inclusion criteria. Five studies were included in this review. The main variables measured were pain, range of motion, hand function, and grip strength. Results show that dry needling is effective in the short term for pain relief and increased range of motion and improved finger grip in patients with mild to moderate carpal tunnel syndrome. There is less literature on the treatment of carpal tunnel syndrome associated with dry needling. As there is some evidence of a positive effect in the short term and in mild to moderate CTS, further randomised clinical trials of good methodological quality using standardised and well-described procedures for the application of dry needling are needed.

Grip Force Measurement as a Complement to High-Resolution Ultrasound in the Diagnosis and Follow-Up of A2 and A4 Finger Pulley Injuries.

The ability of finger flexors to generate force has been studied in relation to climbing performance. However, not much attention has been paid to the decrease in finger grip force in relation to annular pulley injuries. The purpose of the present study was to determine if an injured annular pulley implies a finger flexor force decrease, as well as its relation to clinical and sonographic changes. We performed an observational study in 39 rock climbers with A2 or A4 pulley injuries to the 3rd or 4th fingers. The variables considered were pain upon palpation, ultrasound tendon–bone distance, and finger grip strength decrease. Three rock climbing grip types were considered: the one finger crimp, open crimp, and close crimp. Injured rock climbers presented a decrease in finger grip strength compared to non-injured controls when performing a one finger crimp (p < 0.001). There exists a significant correlation between a tendon–bone distance at the level of the injured pulley and a decreased finger grip strength measured by performing a one finger crimp (p = 0.006). A decrease in finger grip strength could be considered in the diagnostic and follow-up process of A2 and A4 pulley injuries to the 3rd and 4th fingers.

A Finger Grip Force Sensor with an Open-Pad Structure for Glove-Type Assistive Devices.

This paper presents a fingertip grip force sensor based on custom capacitive sensors for glove-type assistive devices with an open-pad structure. The design of the sensor allows using human tactile sensations during grasping and manipulating an object. The proposed sensor can be attached on both sides of the fingertip and measure the force caused by the expansion of the fingertip tissue when a grasping force is applied to the fingertip. The number of measurable degrees of freedom (DoFs) are the two DoFs (flexion and adduction) for the thumb and one DoF (flexion) for the index and middle fingers. The proposed sensor allows the combination with a glove-type assistive device to measure the fingertip force. Calibration was performed for each finger joint angle because the variations in the expansion of the fingertip tissue depend on the joint angles. The root mean square error (RMSE) for fingertip force estimation ranged from 3.75% to 9.71% after calibration, regardless of the finger joint angles or finger posture.

Manual tool grip span and grip force during flower cutting

To analyze the association between grip span of a manual flower cutting tool and maximum peak force exerted by each finger in the operating hand during apprehension. An experiment was conducted in which 11 women performed the stem cut of a flower. These women did not suffer from carpal tunnel syndrome. Grip span was calculated when they exerted the maximum peak force with each finger. The main finding of the study reveals that fingers exert the maximum peak force when the grip span values are the same for everyone. However, due to the shape of the tool commonly used in the Colombian flower industry (first order level), each finger reaches its maximum peak force at different times, bypassing the full capacity of each finger's grip force. These findings could be used to improve the mechanical advantage of manual cutting tools to reduce risk factors for carpal tunnel syndrome due to overexertion.

경량 의수용 SMA 구동식 생체모방 손가락 모듈

This paper proposes a biomimetic finger module to be used in a lightweight hand prosthesis. The finger module consists of finger skeleton and an actuator module driven by SMA (Shape Memory Alloy). The prototype finger module can perform flexion and extension motions; finger flexion is driven by a contraction force of SMA, but it is extended by an elastic force of an extension spring inserted into the finger skeleton. The finger motions are controlled by feedback of electric resistance of SMA because the finger module has no sensors to measure length and angle. Total weight of a prototype finger module is 30g. In experiments the finger motions and finger grip force are tested and compared with simulation results when a constant contraction force of SMA is given. The experimental results show that the proposed SMA-driven finger module is feasible to the lightweight hand prosthesis.

Biodynamic Response of Human Fingers in a Power Grip Subjected to a Random Vibration

Knowledge of the biodynamic response (BR) of the human hand-arm system is an important part of the foundation for the measurement and assessment of hand-transmitted vibration exposure. This study investigated the BR of human fingers in a power grip subjected to a random vibration. Ten male subjects were used in the experiment. Each subject applied three coupling actions to a simulated tool handle at three different finger grip force levels. The BR is practically independent of the hand coupling actions for frequencies at or above 100 Hz. Above 50 Hz, the BR is correlated to finger and hand sizes. Increasing the finger coupling force significantly increases the BR. Therefore, hand forces should be measured and used when assessing hand-transmitted vibration exposure. The results also show that under a constant-velocity vibration, the finger vibration power absorption at frequencies above 200 Hz is approximately twice that at frequencies below 100 Hz. This suggests that the frequency weighting specified in the current ISO 5349-1 (2001) may underestimate the high frequency effect on vibration-induced finger disorders.

Individual finger forces acting on a grasped object during shaking actions.

Individual finger grip forces acting on a hand-held object were examined during shaking tasks with a five-finger precision grip. The subjects (n = 13) shook a force transducer-equipped grip object (mass = 400 g) in vertical, horizontal, and mediolateral directions at an average movement speed of 33 cm/s (moderate) and 66 cm/s (fast). In addition, grip forces were examined while the subjects (n = 10) held the object in front of the body and walked or ran in place. It was found that the grip forces for all the fingers changed temporally and spatially coupling with the acceleration of the object resulting from shaking. The results suggest that grip force control is accomplished in an active and anticipatory fashion. Regardless of the shaking direction and speed, among the four fingers the absolute grip force in the index finger was largest, followed by the middle, ring, and little finger forces. The index finger therefore plays a primary role in grip force control during shaking. The percent force contribution by each finger varied depending on the direction of shaking. Contributions of the ring and little fingers were larger when shaken in the horizontal and mediolateral directions than they were in the vertical direction. The results suggest that different finger co-ordination is required in relation to shaking direction. Changes in shaking speed from moderate to fast changed the grip forces for all the fingers. During walking and running, grip force control similar to that during active vertical shaking was required to hold the object safely in the hand.

Contributions and co-ordination of individual fingers in multiple finger prehension.

The contributions and co-ordination of external finger grip forces were examined during a lifting task with a precision grip using multiple fingers. The subjects (n = 10) lifted a force transducer-equipped grip apparatus. Grip force from each of the five fingers was continuously measured under different object weight (200 g, 400 g and 800 g) and surface structure (plastic and sandpaper) conditions. The effect of five-, four-, and three-finger grip modes was also examined. It was found that variation of object weight or surface friction resulted in change of the total grip force magnitude; the largest change in finger force, was that for the index finger, followed by the middle, ring, and little fingers. Percentage contribution of static grip force to the total grip force for the index, middle, ring, and little fingers was 42.0%, 27.4%, 17.6% and 12.9%, respectively. These values were fairly constant for all object weight conditions, as well as for all surface friction conditions, suggesting that all individual finger force adjustments for light loads less than 800 g are controlled comprehensively simply by using a single common scaling value. A higher surface friction provided faster lifting initiation and required lesser grip force exertion, indicating advantageous effect of a non-slippery surface over a slippery surface. The results indicate that nearly 40% force reduction can be obtained when a non-slippery surface is used. Variation in grip mode changed the total grip force, i.e., the fewer the number of fingers, the greater the total grip force. The percent value of static grip force for the index, middle, and ring fingers in the four-finger grip mode was 42.7%, 32.5%, and 24.7%, respectively, and that for the index and middle fingers in the three-finger grip mode was 43.0% and 56.9%, respectively. Therefore, the grip mode was found to influence the force contributions of the middle and ring fingers, but not of the index finger.

Maximum Finger Force Prediction Using a Planar Simulation of the Middle Finger

Maximum isometric finger-grip forces were predicted using a biomechanical model for plane motion of the middle finger. In the course of this study, mathematical representations of tendon displacement, the moment arm of tendon at the finger joints and muscle force-length relationship were investigated. The information gathered was applied to the model to estimate the maximum grip force of the middle finger gripping cylinders of different sizes. Muscle force per unit physiological cross-section area of 30 N/cm2 resulted in good agreement with measured force. However, for finger postures having an acute proximal interphalangeal joint angle, the estimated force was greater than that measured. Various joint angles were applied to the model to simulate the wrist and finger postures not limited to the cylinder grip. In general the finger force was greatest with the wrist in its extended position and at acute flexion of the proximal interphalangeal joint. The maximum finger force occurred at reduced metacarpophalangeal joint angles as the wrist joint changed from an extended position to a flexed one. It is also postulated that muscle force-length relationship is an important factor in muscle force predictions. The data obtained by this research are useful for the design of handles and the current model is applicable to the analysis of hand postures for workers using hand tools.