Upper extremity biomechanics in native and non-native signers

Area of Science:

• Biomechanics
• Kinesiology
• Sign Language Studies

Background:

• Sign language users born to non-signing parents (non-natives) may face higher injury risks than those born to deaf parents (natives).
• Previous research has not comprehensively analyzed movement patterns during signing in these groups.

Purpose of the Study:

• To investigate and compare upper extremity biomechanics between native and non-native sign language users.
• To identify potential biomechanical factors contributing to injury prevalence differences.

Main Methods:

• Evaluated strength, muscle activation, rest periods, ballistic movements, joint angles, and work envelope during signing.
• Compared these biomechanical parameters between native and non-native signer groups.

Main Results:

• Non-native signers showed less rest and greater muscle activation in the trapezius.
• Native signers exhibited greater ballistic signing (jerk), wrist range of motion, and a larger work envelope.
• Significant differences (p<0.05) were observed across multiple parameters.

Conclusions:

• Native signers demonstrate unique biomechanical characteristics, including increased ballistic movement and joint mobility.
• These findings suggest potential biomechanical underpinnings for observed injury differences between native and non-native signers.
• Further research is warranted to establish direct links between these biomechanical factors and injury risk.