Tomohiro Yasuda

Background: More than 20% of young Japanese women fall into the category of presarcopenia (only the skeletal muscle mass is below the sarcopenia criteria), and it has recently been pointed out that thinness in young adult women may be associated with future problems related to sarcopenia (age-related muscle weakness). However, the problem of sarcopenia is related to skeletal muscle, and body mass index (BMI) cannot assess only skeletal muscle. Objective: Prepregnancy BMI does not assess body composition and may not adequately assess the physical health of pregnant women. Design: The study employed a longitudinal study design. Methods: The purpose of this study was to examine the possibility that health problems caused by sarcopenia may be overlooked if pregnant women are classified using prepregnancy BMI. Fifty-one first-time mothers without underlying medical conditions (underweight (BMI < 18.5 kg/m ² , n = 8), normal weight (18.5 kg/m ² < BMI < 25 kg/m ² , n = 39) and obese (25 kg/m ² < BMI < 30 kg/m ² , n = 4) groups) were included. Skeletal muscle index (SMI = (two upper limb muscle mass + two lower limb muscle mass)/height ² ) and maximum voluntary isometric contraction of grip strength used in European and Asian sarcopenia diagnostic criteria were used to assess sarcopenia in mid- and late pregnancy. Results: For the normal-weight and underweight groups in mid- and late pregnancy, 12%–16% of participants met the diagnostic criteria for sarcopenia according to grip strength (2 ) and 4%–8% of participants met the diagnostic criteria for sarcopenia according to both grip strength and the SMI. Conclusion: Among the pregnant women who were classified as ‘normal’ based on their prepregnancy BMI, 12%–26% had sarcopenia. It is therefore suggested that pregnant women’s health problems could be more appropriately assessed by body composition rather than by BMI classification.

Background and aim: Low birth weight (birth weight of less than 2500 g) among Japanese women has a negative impact on physical form and physical strength evaluation in young adulthood, but there are very few research reports on birth weight and physical form and strength in young adulthood. In addition, there may be differences in the impact of birth weight on physical form and physical strength in young adulthood between men and women, as the extreme desire to be thin that is common among young adult women in Japan is not seen among young adult men. This study aimed to examine the impact of birth weight on the morphology, body composition, and muscle strength of Japanese adult men and women. Method: A total of 107 young adults (39 men and 68 women) participated in the study, and the Pearson product-moment correlation coefficients between birth weight and height, weight, BMI, skeletal muscle index (SMI), grip strength, knee extension strength, and chair stand test were examined. Multiple regression analysis was performed using the items that showed a significant relationship with birth weight as independent variables. Results: The birth weight of women was significantly correlated with height, weight, skeletal muscle index (SMI), regional subcutaneous fat, regional skeletal muscle mass, grip strength, and knee extension strength. Multiple regression analysis revealed that only the skeletal muscle mass of the right leg was affected, and the coefficient of determination (R2) was 0.202 (p=0.01). However, no significant correlation was found between birth weight and any of the variables in men, so multiple regression analysis was not performed. Conclusion: Unlike in men, the birth weight of women has an impact on their body composition, muscle strength, and physical form in young adulthood. In particular, the results suggest that birth weight may have a strong impact on lower-limb muscle mass and that women's birth weight may be a factor to consider when determining the risk of becoming bedridden in the future and its impact on the next generation.

[Objective] To evaluate the efficacy and safety of KAATSU training via remote guidance over three months on body composition, muscle strength, and quality of life (QOL) in a patient who underwent nephrectomy for renal cell carcinoma (RCC).[Methods] The subject was a female pianist in her 40s who was diagnosed with stage 3A (T3A) renal cell carcinoma and underwent left nephrectomy on April 10, 2024. Approximately 5 months postoperatively, she began a 3-month remote KAATSU program combining upper and lower limb exercises. Pre- and post-intervention assessments included body composition analysis, handgrip strength measurement, medical safety serum markers (creatinine, CPK, CRP), and QOL evaluation using the SF-36.[Results] Training was completed safely without adverse events, as medical markers remained stable. Body weight increased significantly (from 47.7 kg to 48.8 kg, p=0.001), and fat-free mass similarly increased (from 34.4 kg to 35.5 kg, p=0.001). Skeletal muscle mass (SMM) increased significantly in the left arm, right arm, and right leg. Grip strength showed no significant change. Physical function (SF-36) showed slight improvement, but clinically declines (≥10 points) were observed in the subscales for physical role, emotional role, and mental health.[Conclusion] Remote KAATSU training was demonstrated to be a safe and effective strategy for improving body composition and suppressing muscle mass loss in stage 3A renal cell carcinoma patients under strict dietary restrictions. However, the decline in mental QOL subscales suggests that the significant effort required for lifestyle changes (diet and exercise) after cancer treatment may impose psychological burden on patients, necessitating further consideration in rehabilitation protocols. This is the first case report detailing the application of KAATSU training in renal cell carcinoma patients.

This study examined the effects of birth weight on body composition, physical fitness, and sarcopenia in adulthood among young Japanese women. Seventy young adult women (birth weight n = 13] and ≥2500 g classified as not low-birth-weight group [NL-BW, n = 57]) were evaluated for body composition, physical fitness, and sarcopenia. Skeletal muscle mass was significantly greater (p0.05). Except for SMI (p0.05). In conclusion, L-BW female infants were shorter in standing height and smaller in skeletal muscle mass in terms of morphology at the time of young adulthood compared to NL-BW female infants. In addition, in terms of physical fitness, those with L-BW also had a lower-limb power score and a higher proportion of low skeletal muscle mass. Thus, it was suggested that low birth weight infants may be at risk of needing nursing care in old age (i.e., a high predicted incidence of sarcopenia) as well as thinness problems in the fertile generation.

Background: Long-term and prolonged piano performance does not provide essential skeletal muscle training benefits while increasing the risk of injury to the upper extremities. Unlike high-intensity exercise training, moderate blood flow restriction (BFR) training has been found to improve neuromuscular mechanisms with a variety of physical exercises (machine, elastic band, walking, electrical stimulation, and body weight). Aim and methods: We investigated the physiological and perceptual responses related to piano performance with or without BFR based on acute responses of neuromuscular mechanisms. Student or professional pianists (n=7) performed the "Revolutionary Etude" on the piano with (Piano-BFR) and without (Piano-Ctrl) BFR. During the Piano-BFR performance, 150-180 mmHg of cuff pressure was applied around the most proximal region of both arms as a moderate BFR. Results: Changes in upper limb girth, muscle thickness, and hand grip strength were measured before and immediately after the performance. After the performance, perceptual and other responses were recorded. Immediately after the performance, the Piano-BFR condition induced greater changes in girth (forearm and upper arm), muscle thickness (forearm), and handgrip strength than the Piano-Ctrl condition. Piano-BFR was (p<0.01) higher than Piano-Ctrl on eight questions regarding perceptual response (upper arm fatigue and difficulty playing the piano). Piano performance with BFR was revealed to increase upper extremity muscle size and fatigue in pianists after playing. Conclusion: Piano performance with BFR was revealed to increase upper extremity muscle size and fatigue in pianists after playing. The effect of BFR on neuromuscular mechanisms on piano performance was greater in the forearm than in the upper arm.

Objective: Making the diagnosis of sarcopenia is not always easy and this is especially true for those with cardiovascular disease. The purpose of this study is to investigate whether it is possible to diagnose sarcopenia by using ultrasound-guided measurements of anterior femoral muscle thickness. Methods: We investigated the utility of ultrasound-guided measurements of anterior femoral muscle thickness in 1075 hospitalized patients with cardiovascular disease (675 men). As a comparison, sarcopenia was assessed by skeletal muscle mass index using bioelectrical impedance analysis and the Asia Working Group for Sarcopenia criteria. Results: When the receiver operating characteristic curve using muscle thickness was examined, we found this could be used to make the diagnosis of sarcopenia (men: cutoff value 2.425 cm, area under the curve 0.796; women: cutoff value 1.995 cm, area under the curve 0.746). The prevalence of sarcopenia according to the criteria with skeletal muscle mass index was 34.2% in men and 51.8% in women, while its prevalence according to the cutoff value of muscle thickness was 29.2% in men and 36.7% in women. Conclusion: Ultrasound-guided measurement of the anterior femoral muscle thickness is a simple and useful method to help make the diagnosis of sarcopenia in patients with cardiovascular disease.

I examined the actual situation of the desire to be thin among young Japanese women from the perspective of ideal body shape and actual measured body shape. In total, 90 young Japanese women were evaluated using a questionnaire (perceived body shape and desired body composition change) and assessments of sarcopenia (muscle strength, physical ability, and muscle mass). Participants were classified into the underweight (body mass index [BMI] < 18.5 kg/m², 74%), normal-weight (18.5 ≤ BMI < 25 kg/m², 20%), or obese (25 ≤ BMI < 30 kg/m², 6%) groups. The normal-weight group needed to gain an average of 2.2 kg to reach the objective ideal weight, but participants desired to lose an average of 4.5 kg. The underweight group needed to gain an average of 10.3 kg to reach the objective ideal weight, but participants desired to maintain their current body weight. Data on muscle mass for the diagnosis of sarcopenia showed low values for the underweight group. Most participants were classified into the normal-weight and underweight groups, but these groups showed a high percentage of women with a desire to be thin. The body shape of young adult women should be carefully considered not only as a health issue of thinness during the fertile period but also as a countermeasure to sarcopenia (low skeletal muscle mass) during the aging process.

We investigated the physiological and perceptual responses related to piano performance with or without moderate blood flow restriction (BFR) based on acute responses of neuromuscular mechanisms. Student or professional pianists (n = 7) performed the "Revolutionary Etude" on the piano with (Piano-BFR) and without (Piano-Ctrl) BFR. During the Piano-BFR performance, 150–180 mmHg of cuff pressure was applied around the most proximal region of both arms as a moderate BFR. Changes in upper limb girth, muscle thickness, and hand grip strength were measured before and immediately after the performance. After the performance, perceptual and other responses were recorded. Immediately after the performance, the Piano-BFR condition induced greater changes in girth (forearm and upper arm), muscle thickness (forearm), and handgrip strength than the Piano-Ctrl condition. Piano-BFR was (p < 0.01) higher than Piano-Ctrl on eight questions regarding perceptual response (upper arm fatigue and difficulty playing the piano). Piano performance with BFR was revealed to increase upper extremity muscle size and fatigue in pianists after playing. The effect of BFR on neuromuscular mechanisms on piano performance was greater in the forearm than in the upper arm.

We examined the actual situation of the desire to be thin among young Japanese women from the perspective of ideal body shape and actual measured body shape. In total, 90 young Japanese women were evaluated using a questionnaire (perceived body shape and desired body composition change) and assessments of physical fitness and sarcopenia (muscle strength, physical ability, and muscle mass). Participants were classified into the underweight (74%), normal (20%), or obesity (6%) groups. The normal weight group needed to gain 2.2 kg to become ideal, but participants desired a 4.5 kg weight loss (p0.05) among the groups regarding the other physical fitness assessments, except for knee extension strength. Data on muscle mass for the sarcopenia diagnosis showed low values for the underweight group. Most participants were classified as the normal and underweight groups, but these groups showed a high percentage of a desire to be thin. The body shape of young adult women should be carefully considered not only as a health issue of thinness during the fertile period but also as a sarcopenia countermeasure (low skeletal muscle mass) for the ageing period.

The purpose of this study was to compare the fitness levels of healthy young Japanese adults based on the “old” and “new” sarcopenia versions of the European Working Group on Sarcopenia in the Older People (EWGSOP1 and EWGSOP2) and the Asian Working Group for Sarcopenia (AWGS 2014 and AWGS 2019) criteria. Sixty-nine Japanese young adults were evaluated using the diagnostic criteria and classification of sarcopenia (muscle strength, physical ability, and muscle mass). For both sexes, the percentage classified as “robust” on the sarcopenia diagnostic criteria was lower in “old” than in “new” classification. The “sarcopenia” category comprised 2% of females only, but none of them had “severe sarcopenia”. The proportion of participants with “presarcopenia” (old classification) was 19-38%, and that with “possible sarcopenia” (new classification) was 2% for females only. A higher proportion of healthy young adults were classified as “robust” in “new” compared to “old” because "presarcopenia" was eliminated in “new”. Moreover, since the proportion of low muscle mass exists in one-fifth of males and one-third of females, it would be difficult to use the new criteria to promote muscle mass gains and prevent from a young age to care for the future.