Sporting Hand and Wrist - Why Power and Pinch Grips Matter

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Types of Grip

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 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.

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.

The hand-wrist represents the most sophisticated tool in the human being. Hand function and strength are important elements in day to day life and participation in sports .

1-Power Grip: closing a hand with the thumb in opposition to all other fingers together generates a power grip.

A-Lumbrical grip

B-Spherical grip

C-Hammer grip

D-Hook grip

Lumbrical grip	Spherical grip	Hammer grip	Hook grip

2-Pinch grip: the holding of an object between the thumb and fingers of a single hand. The tip pinch between thumb and fingertip is used for fine manipulation. generated by pressing the thumb pulp against the pulp of the index, middle, ring, and little fingers’ distal phalanges.

A-Tip Pinch: index pressing against the thumb.

B-Tripod Pinch: adding the middle finger.Tri-digit 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. . Lateral (key) pinch is stronger because fingers resist the pressure of the thumb.

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 three-point pinch. Tip-to-tip pinch is used for more sophisticated processes requiring fine coordination. Pinch function of the hand is

The grip function of the hand is of great importance in professional and daily life activities. There are four main items to classify and assess the grip. Daily activities are generally the combinations of these different types of grips

Tip Pinch	Tripod Pinch	Lateral Pinch

Gripping in Day to Day Life

The loss of grip strength is associated with many pathologies. Hand Osteoarthritis is a common condition that causes joint pain resulting in gradual loss of grip power. There are numerous factors 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.

Grip strength could be affected by cold weather due to reduced muscle contraction and overall grip 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 should be 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

Different sports require different grips, often differs between hands. 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 will use a power grip. Whereas the backhand, pulling the string, also in power grip but the thumb is less involved going into more adduction.

Raquet 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 change.

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 Strength

Considerations:

Dynamometer: 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
• analog 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 analog display

When testing strength, it's good to note the associated symptoms and the difference between the right and left hands

Testing for 3 times. A tip: start with the non-painful side then move on the other hand and alternate the testing between hands for three times

Looking for the peak force referring to the best number. 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:

1- 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.

2- testing from straight elbow position and wrist in neutral isolate hand muscles.

Comparing to the other side rather than how strong it. Consider the element of chronicity could lead to weakness due to reciprocal inhibition

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 both 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. 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 in the same study.

Rehabilitation of Grip

Power Grip:

A case study of a boxing injury: Handgrip strength was tripled in three weeks of conservative management and the difference dropped from 87% to 15% on testing between right and left hands

Functional rehabilitation is recommended. Monitoring symptoms and progression into function training and power grip training.

Isokinetic training machine:

Expensive but a useful kinetic machine

Can be used to measure the flexor/extensor muscle strength both eccentrically and concentrically with speed variations. The same measures could be adjusted for rehabilitation.

Other equipment:

rubber tools also known as flex bars. Can be used in different forms to target the wrist and forearm muscles. Also can be used for different purposes, strength and conditioning. The Intensity is linked with the number of repetitions but you can advice different colours for different strengths.

Crushes: is another tool that could be used to improve the power grip. The spring can change the strength.

Talon grips: designed ergonomically to adapt to the shape of the hand to give uniform loading on the tendons, can be used with pull-ups.

The width of the grip used by the athlete is a factor to be considered such as in rugby or Javalin and putters and the amount of time the athlete is gripping.

Pinch Grip:

There are two different types of dynamometers.

Pinch grip dynamometer or handheld dynamometer: there are two positions to hold and exercise from.

key grip: useful to strengthen the flexors and places the joint in a closed position. Involves the thumb more than the pinch grip.

The use of which grip or position depends on the onset and severity of injury.

Handheld dynamometer for pinch grip strength

Key Grip

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A plate can be used to strengthen the grip: there are different variations depending on which muscles to involve. The time to hold can be adjusted on the type of training and also could be used to check the maximum hold between right and left hands.

Key grip

Pinch grip

Monitoring the symptoms associated withholding such as pain, time of occurrence and effect on holding can be useful data int eh management.

Putty: can help with a pinch grip using different variations

Flipping Plates: good exercise to improve thumb and wrist proprioception.