Aerobic system analysis based on oxygen uptake and hip acceleration during random over-ground walking activities.

Area of Science:

• Cardiorespiratory Physiology
• Exercise Science
• Biomedical Engineering

Background:

• Deteriorated aerobic response may precede noncommunicable disease symptoms.
• Assessing aerobic response in realistic settings is crucial for early detection.
• Current methods often lack ecological validity.

Purpose of the Study:

• To validate wearable technology for analyzing pulmonary oxygen uptake (V̇o₂) dynamics during over-ground walking.
• To investigate the suitability of a pseudorandom ternary sequence (PRTS) walking protocol for assessing aerobic response.
• To correlate findings with established exercise testing methods.

Main Methods:

• Eight adults performed PRTS over-ground walking and cycle ergometer protocols (PRBS and incremental).
• Wearable hip accelerometers measured input changes to the aerobic system.
• Pulmonary oxygen uptake (V̇o₂) dynamics were quantified using mean normalized gain amplitude (MNG) in the frequency domain.

Main Results:

• MNG during PRTS walking correlated significantly with the V̇o₂ time constant from cycling (r = -0.80).
• MNG estimates from PRBS and PRTS protocols showed strong agreement (r = 0.80).
• Maximal V̇o₂ correlated with MNG from both PRBS and PRTS protocols (r ≈ 0.78-0.79).

Conclusions:

• The PRTS over-ground walking protocol, using wearable sensors, effectively evaluates aerobic system dynamics.
• Aerobic response dynamics measured during PRTS and PRBS correlate with maximal V̇o₂.
• Wearable technology and MNG assessment enable realistic cardiorespiratory health monitoring.