2019 Volume 15 Issue 1 Pages 5-8
[Purpose] KAATSU training is a method that increases muscle activity even at low loads. In this study, we examined how different KAATSU pressure modulates elbow flexor activities during low-load elbow flexion and extension in an elderly female frail patient.
[Method] A 89-year-old female patient who had repeated hospitalization due to chronic heart failure and undergone transcatheter aortic valve implantation (TAVI) for severe aortic stenosis participated in this study. The participant performed a series of right elbow flexion and extension with a 500g weight wound around the right wrist joint and surface electromyograms (EMG) of right biceps brachii (BB) and brachioradialis (BR) were recorded. The exercises conditions were in control (without KAATSU, KAATSU 0), 120 SKU (KAATSU 120) and 150 SKU (KAATSU 150) on the proximal part of right upper limb. The number of exercises was 20 trials x 3 sets for each condition. We recorded muscle strength of maximum isometric voluntary contraction (MVC) measured with a hand-held dynamometer before the start of each condition. EMG was expressed as %MVC and averaged for flexion and extension phase in each condition. A rate of perceived exertion (RPE) after each set was measured by the Borg Scale.
[Results] There was no change in muscle strength during MVC before each condition. Compared with KAATSU 0, EMG activity of both BB and BR increased during flexion in KAATSU 120 and 150. Under KAATSU 120, BB activity increased in the first half of the flexion phase and BR activity increased throughout the flexion phase. Although RPE under KAATSU 150 was higher than KAATSU 120, both EMG activities under pressure 150 was lower than under KAATSU 120.
[Conclusion] An elderly female frail patient who had received TAVI showed that muscle activity under KAATSU 120 was the highest during low-load elbow flexion and extension exercises, while RPE was second highest. These results suggest that an appropriate KAATSU pressure will increase muscle activity during low-load exercise while minimize an increase of participant's burden.