Use of Dynamometer to Measure Grip and Pinch Strength in Clinical Practice

Overview

• Different brands of dynamometers, with Jamar being the most popular.
• Measurement of grip and pinch strength using standardized positions.

Measuring Grip Strength

Equipment: Jamar Dynamometer

• Set the bar at the second groove for all subjects (children, teens, older adults).

Standardized Position

• Shoulder in adduction.
• Elbow at 90° flexion.
• Forearm in neutral.
• Slide the Jamar into the participant's hand.
• Instruct participants to squeeze as hard as possible without holding their breath.
• Take three measurements, average them, and document the average.

Important Notes

• Be consistent in reading units (kg or lbs).
• Holding breath is discouraged, especially for patients who had heart surgery.

Measuring Pinch Strength

Standardized Position

• Same as grip strength for shoulder, elbow, and forearm positions.
• Slide the pinch gauge into the participant's hand.
• Perform measurements for different types of pinches (Palmar pinch, L pinch, tip pinch).
• Take three measurements, average them, and document the average.

Positioning

• If unable to assume standardized positions, document the position used.
• Follow the same position for subsequent measurements to monitor improvement.

Interpreting Results

Using Norms

• Norms are based on standardized positions and calculated using the two-standard deviation method (covering 90% of the population).
• Deviations within two standard deviations above the mean are considered normal, while below are considered abnormal.

Example:

• 45-year-old male with a right grip of 50 lbs.
• Mean for this age and gender is 110 lbs, with a standard deviation of 23.
• Two-standard deviation below the mean is 64 lbs (110 - 46).
• A grip strength below 64 lbs is considered abnormal.

Without Norms

• Use the 10% method for comparing grip strength between right and left hands.
• Right hand dominant: Right grip should be 10% greater than the left.
• Left hand dominant: Right and left grips should be roughly equal.
• Compare within the individual's performance over time.

Special Cases

• Norms may not be applicable for special conditions (e.g., stroke, median nerve injury).
• Compare grip strength between the individual's hands (right to left or left to right).

Key Takeaways

• Measure using standardized methods and positions, or document variations.
• Know how to interpret results using norms or percentage methods.