Upper limb manual dexterity, strength and blood flow after walking with backpack load

Area of Science:

• Biomechanics
• Human Physiology
• Ergonomics

Background:

• Understanding the impact of load carriage on physical performance is crucial for military and occupational settings.
• Previous research has explored the effects of load on lower limb function, but upper limb effects require further characterization.

Purpose of the Study:

• To investigate the effects of backpack load carriage on various upper limb functions in healthy males.
• To compare the functional changes under different load conditions: no load, loaded backpack (BP), and loaded backpack with simulated rifle (BRC).

Main Methods:

• Fifteen healthy males underwent a 45-minute walking trial under three conditions.
• Measurements included pinch strength, grip strength, sensory threshold, blood flow volume, and manual dexterity (Grooved Pegboard test).
• Assessments were conducted before and immediately after the walking trial, with some post-trial measurements taken after a seated recovery period.

Main Results:

• Pinch strength was significantly reduced in the loaded backpack (BP) condition compared to the control.
• Manual dexterity, assessed by Grooved Pegboard test times, improved after a seated recovery period, indicating a temporary impairment immediately post-exercise.
• Blood flow to the upper limb significantly decreased to below 53% of baseline in both BP and BRC conditions immediately after donning the backpack.

Conclusions:

• Backpack load carriage significantly affects upper limb pinch strength and manual dexterity.
• Reduced blood flow in the upper limbs is an immediate consequence of carrying weighted backpacks.
• While grip strength and sensory threshold remained unaffected, the findings suggest specific functional limitations imposed by load carriage.