Grip Strength Device: How to Use, Interpret Results, and Improve Grip

How do you use a grip strength device?

Using a grip strength device, typically a hand dynamometer, involves a standardized protocol: adjust the device to your hand size, adopt a consistent body and arm position (often seated with the elbow at 90 degrees), and then exert a maximal isometric squeeze for a few seconds to obtain an accurate measure of your hand and forearm musculature's peak force.

Understanding Grip Strength Devices

A grip strength device, most commonly a hand dynamometer, is an instrument designed to quantitatively measure the maximum isometric strength of the hand and forearm muscles. This measurement, often expressed in kilograms (kg) or pounds (lbs), provides valuable insight into an individual's overall muscular strength, functional capacity, and even general health status. While various types exist, including spring-based and pneumatic devices, the hydraulic hand dynamometer (e.g., the Jamar dynamometer) is considered the gold standard in clinical and research settings due to its accuracy and reliability.

Why Measure Grip Strength?

Measuring grip strength extends beyond mere curiosity; it serves as a robust indicator for several important health and performance metrics:

• Overall Muscular Strength: Grip strength correlates strongly with total body strength, making it a convenient proxy for general muscular fitness.
• Functional Independence: Adequate grip strength is crucial for daily activities, from opening jars and carrying groceries to maintaining balance and preventing falls, particularly in older adults.
• Health Biomarker: Research consistently links lower grip strength to increased risk of cardiovascular disease, all-cause mortality, sarcopenia (age-related muscle loss), and reduced quality of life. Conversely, maintaining strong grip is associated with better health outcomes and longevity.
• Athletic Performance: Many sports (e.g., weightlifting, climbing, martial arts, racket sports) demand high levels of grip strength for optimal performance, injury prevention, and skill execution.
• Rehabilitation and Progress Tracking: In clinical settings, grip strength is used to assess nerve or muscle damage in the hand and forearm, track recovery post-injury or surgery, and monitor the effectiveness of rehabilitation programs.

Types of Grip Strength Devices

While the principle remains the same, devices vary in mechanism:

• Hydraulic Hand Dynamometers: These are the most common and reliable, using hydraulic fluid to translate force into a reading. They typically feature an adjustable handle to accommodate different hand sizes.
• Spring Hand Dynamometers: Less expensive and more portable, these use a spring mechanism to measure force. While suitable for general tracking, they may offer less precision than hydraulic models.
• Digital Grip Dynamometers: Both hydraulic and spring models can come with digital displays, offering precise readings, data storage, and often compatibility with apps for tracking.

For the purpose of standardized measurement, this guide will focus on the protocol for hydraulic hand dynamometers, which is widely adopted in professional settings.

Step-by-Step Guide to Using a Hand Dynamometer

To ensure accuracy and consistency, follow a standardized protocol, such as the one recommended by the American Society of Hand Therapists (ASHT):

1. Preparation

• Calibrate/Zero the Device: If your dynamometer has a calibration or zeroing function, ensure it's properly set before each use.
• Adjust Handle Position: Most dynamometers have an adjustable handle with multiple settings. Choose the setting that allows your fingers to comfortably curl around the handle with the middle phalanges (middle finger segments) at a right angle to the handle. For most adults, this is typically the second or third position.
• Warm-Up: Perform a brief, light warm-up of the hands and forearms (e.g., gentle wrist circles, finger stretches) to prepare the muscles and prevent injury.
• Record Baseline Data: Note down the date, time, and the hand being tested (left or right).

2. Positioning

• Seated Position: The individual should be seated comfortably in a sturdy chair without armrests.
• Arm Position:
  • Shoulder: Adducted (arm at the side), neutrally rotated.
  • Elbow: Flexed to 90 degrees. This is crucial for isolating forearm flexor strength and minimizing contributions from other muscle groups.
  • Forearm: Neutral position (thumb pointing upwards), not pronated or supinated.
  • Wrist: Maintained in slight extension (0-30 degrees) and neutral ulnar/radial deviation. Avoid excessive wrist flexion or extension as this can reduce force output.
• Device Placement: The dynamometer should be held in the hand with the base resting on the palm and the fingers wrapping around the handle. Ensure the dial or digital display is visible to the tester.

3. Execution

• Verbal Cue: Instruct the individual to "Squeeze as hard as you can!" or "Squeeze hard!"
• Maximal Isometric Contraction: The individual should exert a maximal squeeze for approximately 3 to 5 seconds. Emphasize a smooth, sustained effort rather than a sudden jerk.
• Avoid Valsalva Maneuver: Remind the individual to breathe naturally and avoid holding their breath, which can increase blood pressure (Valsalva maneuver).

4. Reading Results

• Peak Reading: The dynamometer's needle or digital display will hold the peak force achieved during the squeeze.
• Record: Immediately note down the highest reading for that trial.
• Reset: Reset the dynamometer to zero before the next trial.

5. Repetitions and Rest

• Multiple Trials: Typically, three trials are performed for each hand. This helps account for variability and allows for the calculation of an average or the use of the highest score.
• Alternating Hands: If testing both hands, it's common to alternate between hands (e.g., Right 1, Left 1, Right 2, Left 2, etc.) to allow for recovery.
• Rest Interval: Allow a rest period of 30 to 60 seconds between trials on the same hand to prevent fatigue from affecting subsequent measurements.

Interpreting Your Results

Once you have your measurements, consider the following:

• Dominant vs. Non-Dominant Hand: The dominant hand typically exhibits 5-10% greater strength than the non-dominant hand. Significant asymmetries (e.g., >10-15% difference) could indicate an underlying issue or injury.
• Normative Data: Compare your results to age- and sex-specific normative data tables. These tables provide average grip strength values for various populations, helping you understand where you stand relative to your peers.
• Tracking Progress: The most valuable use of grip strength measurement is tracking your own progress over time. Consistent increases indicate improved strength, while declines warrant investigation.

Factors Influencing Grip Strength

Several factors can affect grip strength measurements, highlighting the importance of standardized testing conditions:

• Time of Day: Grip strength can be slightly higher in the afternoon compared to the morning.
• Fatigue: Recent strenuous exercise involving the forearms or hands will temporarily reduce grip strength.
• Hydration Status: Dehydration can negatively impact muscular performance.
• Pain or Injury: Any discomfort or injury in the hand, wrist, or arm will significantly reduce force output.
• Motivation and Effort: The individual's willingness to exert maximal effort is critical for accurate results.
• Handle Position: Using an incorrect handle position can lead to lower readings.

Improving Grip Strength

If your grip strength is a limiting factor or you simply wish to improve it, consider incorporating specific exercises into your routine:

• Crushing Grip: Exercises like deadlifts, farmer's carries, and using specific grip trainers (e.g., Captains of Crush grippers).
• Pinch Grip: Plate pinches (holding weight plates together with your fingertips and thumb), block pinches.
• Support Grip: Hanging from a pull-up bar for time, towel pull-ups, rope climbs.
• Wrist and Forearm Exercises: Wrist curls, reverse wrist curls, pronation/supination exercises.

When to Consult a Professional

While self-assessment is beneficial, consult a healthcare professional, physical therapist, or occupational therapist if you:

• Experience a sudden, unexplained decrease in grip strength.
• Have persistent pain in your hand, wrist, or forearm during or after grip activities.
• Notice significant asymmetry between your dominant and non-dominant hands without a clear reason.
• Are recovering from an injury or surgery and need guidance on rehabilitation and strength progression.

By understanding the proper technique and the factors influencing measurements, you can effectively use a grip strength device to monitor your health, track your fitness progress, and identify areas for improvement.