Determination of friction and pulling forces during a weighted sled pull

Area of Science:

• Biomechanics
• Sports Science
• Friction Analysis

Background:

• Weighted sled exercises are common in training programs.
• Accurate calculation of forces and work performed requires understanding friction coefficients.
• Static friction coefficient (μs) and dynamic friction coefficient (μd) are key parameters.

Purpose of the Study:

• To establish a reliable method for determining μs and μd during weighted sled pulls.
• To quantify horizontal forces and work performed for training, assessment, and research.
• To investigate the impact of different loads on friction coefficients.

Main Methods:

• A force transducer and winch were used to pull a weighted sled at a constant velocity.
• Three different loads (44.8 kg, 90.0 kg, 136.2 kg) were tested.
• Each load was pulled 10 times for a total of 30 trials.

Main Results:

• Static friction coefficients (μs) ranged from 0.39 to 0.47, with low coefficients of variation (CV).
• Dynamic friction coefficients (μd) ranged from 0.31 to 0.35, also showing high repeatability (low CV).
• Combined data yielded μs = 0.43 ± 0.04 and μd = 0.33 ± 0.02.

Conclusions:

• The described method provides highly repeatable measurements of μs and μd for weighted sled pulls.
• The determined friction coefficients are reliable for practical applications in sports and research.
• Coaches and researchers can utilize this methodology for their specific equipment and surfaces.