Predicting metabolic cost of level walking

Area of Science:

• Biomechanics
• Human Physiology
• Exercise Science

Background:

• Energy expenditure during walking is commonly linked solely to walking speed.
• Existing models often overlook the interplay between step length and step rate.
• A comprehensive understanding requires considering both step length and step rate for accurate energy expenditure prediction.

Purpose of the Study:

• To develop a method for predicting energy expenditure across various walking patterns.
• To investigate the impact of freely chosen versus forced step rates on energy demand.
• To establish an energy equation encompassing both free and forced gaits.

Main Methods:

• Conducted two experiments on seven subjects to gather data on energy expenditure.
• Experiment 1: Subjects freely selected their walking pattern (step length and rate) at prescribed speeds.
• Experiment 2: Subjects maintained a constant speed while being forced to adopt various step rates.

Main Results:

• Freely chosen step rates demonstrated the lowest oxygen consumption for any given walking speed.
• Deviations from the freely chosen step rate, under forced conditions, significantly increased oxygen cost.
• The combined data allowed for the determination of a comprehensive energy equation for walking patterns.

Conclusions:

• Walking energy expenditure is influenced by the coordination of step length and step rate, not just speed.
• Natural, self-selected gait patterns are the most energy-efficient for walking.
• Forced alterations in step rate increase metabolic cost, highlighting the importance of preferred movement patterns.