Maximum running speed limitations on terrestrial mammals: a theoretical approach

Area of Science:

• Biomechanics
• Animal Physiology
• Locomotion Science

Background:

• Understanding the factors limiting maximum running speed (MRS) in mammals is crucial for biomechanical and physiological studies.
• Previous models have explored energetic and muscle-tendon unit functions, but specific limitations across a wide body mass range require further investigation.

Purpose of the Study:

• To estimate maximum running speed (MRS) limitations in mammals ranging from 1.5 to 300 kg.
• To analyze the influence of body mass on MRS and compare findings with existing experimental data.
• To identify the most significant anatomical and physiological constraints on mammalian running speed.

Main Methods:

• Utilized a previously proposed model of energetic and muscle-tendon unit functions.
• Estimated MRS and potential limiting factors for mammals within a defined body mass spectrum.
• Compared model-derived MRS variations with data from prior experimental and observational studies.

Main Results:

• Tendon strength emerged as the most critical limitation affecting maximum running speed across the studied body mass range.
• Leg extensor muscle mass and metabolic costs were identified as potentially significant, though secondary, limiting factors.
• Physiological maximum muscle speed appeared to be a less important constraint within the 1.5 to 300 kg body mass range.

Conclusions:

• Mammalian maximum running speed is primarily constrained by the mechanical properties of tendons.
• While muscle properties and energy expenditure contribute, they are secondary to tendon limitations in determining running speed.
• The findings provide valuable insights into the biomechanics of locomotion and evolutionary adaptations in running mammals.