Sporting Hand and Wrist - Why Power and Pinch Grips Matter
Types of Grips
The hand anatomy is efficiently organized to carry out a variety of complex tasks combining intricate movements and finely controlled force production. The soft tissue structure of the hand is complicated and any injury to any of these even very small structures can alter the overall function of the hand and thereby complicate the therapeutic management. Hand function and strength are important elements in day to day life and participation in sports .
Gripping or the ability to fold the fingers into the palms supported by the thenar and hypothenar eminences to make a club-like structure is exclusive to humans.
Closing a hand with the thumb in opposition to all other fingers together generates a power grip.
The holding of an object between the thumb and fingers of a single hand.
A-Tip Pinch: index pressing against the thumb: holding an object between thumb and a fingertip is used for fine manipulation.
B-Tripod Pinch (Chuck pinch): increases the stability by utilizing two fingertips instead of one.
C-Lateral Pinch, also known as key pinch: achieved by pressing the thumb pulp against the lateral aspect of the proximal interphalangeal joint of the index finger. In this grip, the thumb is going into adduction and flexion.
The peak forces generated with the three-digits and lateral pinch grips are about 40% greater than that produced with the tip pinch
Lateral pinch is the strongest type of pinch followed by tripod pinch. Tip pinch is used for more sophisticated processes requiring fine coordination.
Grip Strength in Day to Day Life
Daily activities require a combination of different movements in the upper limb. Hand function is an important component of these movements. The loss of grip strength is associated with a number of pathologies. Hand Osteoarthritis is a is a common chronic condition involving one or more joints of the thumb and fingers. It is associated with pain, reduced grip strength, loss of range of motion (ROM), and joint stiffness leading to impaired hand function and difficulty with daily activities . Stroke is another condition that impacts the upper limb and hand function. Addressing these conditions requires an understanding of the hand anatomy and biomechanics.
There are numerous factors such as sex, age, and hand preference that contribute to the grip strength and they should be considered when making clinical decisions. The average grip strength of women is approximately 60% that of men, and for both sexes, grip strength reaches a maximum during the fourth decade of life and declined thereafter with increasing age.
Cold weather causes reduced muscle contraction and affects grip strength and function of the hand.
It is believed that the difference between the dominant and non-dominant hand in strength is 10% (known as the 10% rule). This applies to right-handed people. For left-handed persons, grip strength is considered equivalent in both hands.
The hand strength in daily activities is classified into three main functional groups:
- Activities are requiring force and rotation (e.g., unscrewing the jar lid)
- Activities are requiring dexterity and precision (e.g., peeling fruits)
- Dynamic activities, primarily based on pinching and performed with the first two or three fingers of the dominant hand (e.g., writing with a pencil)
Grip in Sports
The combination of grips differs according to the type of sports and hand dominance. If you are involved in sports rehabilitation, understanding the type of grip and involvement of the thumb is important to measure the strength and address any related injuries.
Here are some examples of different grips used in various sports:
|Bow and arrow||The lead hand holding the bow and keeping it stable in a power grip. Whereas the backhand, pulling the string, also in power grip but the thumb is less involved going into more adduction.|
|Racquet sports such as tennis:||Hand holding the racket using a power grip and the other hand holding the ball in a pinch grip. By changing the grip, the movement and the force changes.|
|Golf:||Lateral pinch or key grip is used but that could change during the game depending on the movement and how much strength is required.|
|Wheelchair sports, for example, basketball||The hand holding the wheelchair would require more strength from the thumb for stability. the other hand holding the ball would use a spherical grip in which there will be cupping at the wrist and adduction at the thumb.|
|Weight lifting||The use of a hook grip is recommended in weightlifting movements|
|Boxing:||Power grip is used. Injury at the base of the CMC joints of the index and middle fingers is common causing instability and interferes with the gripping power.|
Measuring Grip StrengthMeasuring grip strength is commonly used in research and sports to measure the efficacy of an intervention. It is a useful practice to implement in hand rehabilitation that would help on decision making and reporting outcomes.
Dynamometers: the Jamar and the Takei are the most common studied dynamometers in the literature.
The Jamar dynamometer is considered to be the gold standard for documenting manual grip strength. It is comprised of:
- an adjustable anatomical rigid handle
- hydraulic system
- analogue display
The Takei is a valid and reliable tool to measure power grip. It is comprised of:
- Adjustable rectified
- Complacent handle shape
- Electromechanical system
- A digital or analogue display
- Note the associated symptoms such as pain or instability. The timing of the symptoms also matters whether they accompany the movement or start after the testing.
- The difference between the right and left hands. Consider the element of chronicity could lead to weakness due to reciprocal inhibition.
- Repeat the test for 3 times starting with the non-painful side then move on to the other hand and alternate the testing between hands for three times
- Look for the peak force (the best number that could be achieved on testing). Some people might be able to generate a high number on the strength test but then the number lowers due to fatigue or they take few repetitions to generate the force
- Testing position:
- Elbow in a 90-degree angle: helps to generate the highest peak. However, having the forearm in mid-position could lead to contraction of the brachioradialis muscle and the movement will not be generated purely from the hand.
- Testing from straight elbow position and wrist in neutral. This position is recommended by Gatt I. to isolate hand muscles.
Injuries and Grip Strength
A study by Loosemore et al explored hand and wrist injuries in both training and competitions in boxing found:
- Boxer's Knuckles (Finger carpometacarpal instability and finger metacarpophalangeal joint extensor hood and capsule sprain) to be the most common injury.
- The incidence of training injuries was similar to that of competition injuries.
The study also measured the grip strength in right and left hands at baseline and after injuries and concluded:
- A difference of 15% between both hands is considered normal
- Boxers who had a difference of 20% are likely to have an injury.
- A difference of higher than 20% places the athlete at a higher risk for pathologies.
- Following an injury, an 87% difference in bilateral hand gripping strength was observed.
Example of injuries affecting Grip strength:
- Pulley ruptures
- Thumb ligament injuries
- Bennett's fracture
- Traumatic Extensor Hood Rupture
- Extensor Tendon Injuries of the Fingers and Hand
- Flexor Tendon Injuries
- skier’s thumb
- Ulnar abutment
- Triangular fibrocartilage complex tears
- Metacarpal fractures
Rehabilitation of Grip Strength
As mentioned earlier, it's important to understand the factors contributing to the grip strength.
Handgrip measuring should be a key component during the rehabilitation process to measure effectiveness.
The available interventions to rehabilitate grip strength are numerous. The selection of the intervention depends on the individual factors, type of sport and used grip, the type of injury, chronicity, severity and also the associated pathologies.
A case study of a boxing injury conducted by Gatt reported a triple increase in handgrip strength and a drop of right-left hands strength difference from 87% to 15% following three weeks of conservative management. A functional rehabilitation approach is recommended with monitoring of symptoms and gradual progression into functional and power grip training.
Examples of power grip interventions:
1-Isokinetic training machine:
Expensive but a useful kinetic machine. Could be implemented as testing and also as training equipment for different wrist and hand muscles at both eccentric and concentric measures with speed variations.2-Rubber tools also known as flex bars. Different colours could be deployed for varying strength and targeting the wrist and forearm muscles.
4-Talon grips: could be added to pull-ups. A tool that is designed ergonomically to adapt to the shape of the hand and give a uniform loading on the tendons,
Examples of pinch grip interventions:1-Pinch grip dynamometer or handheld dynamometer: there are two positions to perform the exercise from as in the image:
The decision on the use of which grip (key or pinch) depends on the onset and severity of the injury.
3- Holding a plate: there are different variations depending on the targeted muscles. The time to hold can be adjusted on the type of training e.g. conditioning or endurance, and also could be used to check the difference in the maximum hold between right and left hands. Monitoring the symptoms associated with holding the plate such as pain, the timing of the symptoms and the effect on holding can be useful data in the management.
4-Putty: for pinch or power grip using different variations:
5-Flipping Plates: good exercise to improve thumb and wrist proprioception.
- Duruoz MT. Hand function. Springer-Verlag New York; 2016.
- Gatt I, Smith-Moore S, Steggles C, Loosemore M. The takei handheld dynamometer: an effective clinical outcome measure tool for hand and wrist function in boxing. HAND. 2018 May;13(3):319-24.
- Loosemore M, Lightfoot J, Gatt I, Hayton M, Beardsley C. Hand and wrist injuries in elite boxing: a longitudinal prospective study (2005-2012) of the Great Britain Olympic Boxing Squad. Hand. 2017 Mar;12(2):181-7.
- Gatt I. Hand and wrist injuries: a focus on boxing. A Comprehensive Guide to Sports Physiology and Injury Management E-Book: An Interdisciplinary Approach. 2020 Nov 28:315.
- Gatt I. Sporting Hand & Wrist - Why Power & Pinch Grips Matter. Physioplus Course 2020
- Magni NE, McNair PJ, Rice DA. The effects of resistance training on muscle strength, joint pain, and hand function in individuals with hand osteoarthritis: a systematic review and meta-analysis. Arthritis research & therapy. 2017 Dec 1;19(1):131.
- Duruöz MT, Poiraudeau S, Fermanian J, et al. Development and validation of a rheumatoid hand functional disability scale that assess functional handicap. J Rheumatol. 1996;23:1167–72.
- Oranchuk DJ, Drinkwater EJ, Lindsay RS, Helms ER, Harbour ET, Storey AG. Improvement of kinetic, kinematic, and qualitative performance variables of the power clean with the hook grip. International journal of sports physiology and performance. 2019 Mar 1;14(3):378-84.
- Hand Grip Dynamometer. Available from:https://www.youtube.com/watch?v=-jmWNKUek3o[last accessed 28/12/2020]
- Pinch grip strength putty R. Available from:https://www.youtube.com/watch?v=QxaP5P9CSWc[last accessed 28/12/2020]
- Power grip strength putty R. Available from:https://www.youtube.com/watch?v=DufAYWGidsc[last accessed 28/12/2020]
- Plate Flip | Better Grip | Forearm Strength | Move and Perform Better. Available from:https://www.youtube.com/watch?v=Z-qNThP5Sjw[last accessed 28/12/2020]