[Objective] We examined the effects of moderate blood flow restriction due to KAATSU on rectus femoris activation, heart rate (HR), and ratings of perceived exertion (RPE) while cycling at an intensity just below anaerobic threshold (AT).

[Methods] A healthy young male (age = 23 y) performed symptom-limited graded exercise testing on a cycle ergometer with KAATSU (180 SKU) or without KAATSU on 2 separate days. We recorded surface electromyogram (EMG) from the right rectus femoris, HR, RPE for breathlessness and effort in lower limbs.

[Results] The participant reached AT with lower physical and perceived effort with KAATSU than without KAATSU. Muscle activation was similar during exercise between with and without KAATSU just below AT.

[Conclusion] Exercise just below AT with KAATSU vs. without KAATSU elicited lower physical and perceived effort without difference in muscle activation. Therefore, low-intensity aerobic exercise with KAATSU might be an effective, low-burden, and safe method for the rehabilitation of patients with cardiovascular disease.