Second Metatarsal Bone Stress During Running Is Independently Influenced by Running Speed and Load Carriage

Area of Science:

• Biomechanics
• Sports Medicine
• Orthopedics

Background:

• Bone stress injuries (BSIs) are common in athletes and military personnel due to repetitive loading.
• The second metatarsal is a frequent site for BSIs.
• Running speed and load carriage are potential modifiable risk factors for metatarsal BSIs.

Purpose of the Study:

• To investigate the effects of varying running speeds (preferred, 90% preferred, 110% preferred) and load carriage (0% and 10% body mass) on second metatarsal bone stress.
• To quantify the impact of these factors on peak bone stress at the dorsal and plantar surfaces of the second metatarsal midshaft.

Main Methods:

• Data collected from 28 runners (14 female, 14 male) during barefoot running.
• Utilized motion capture cameras, a pressure plate, and a force plate for data acquisition.
• Calculated bone stress using a two-dimensional beam theory model on the second metatarsal.

Main Results:

• Running at 110% of preferred speed increased peak dorsal and plantar stress by 4.2%.
• Running with 10% body mass increased peak dorsal and plantar stress by approximately 3%.
• No significant interaction effect was observed between running speed and load carriage.

Conclusions:

• Increased running speed and added load significantly elevate second metatarsal bone stress.
• High inter-participant variability in bone stress (25% coefficient of variation) underscores the need for individualized injury risk assessment.
• Modifying running speed and load carriage may be crucial for preventing second metatarsal bone stress injuries.