We investigated whether the autonomic nervous system (ANS) modulation contribute to the bradycardia induced by endurance training. First, the meta-analysis approach was used to collect group mean values of maximal oxygen consumption (Vo₂max) and heart rate variability (HRV) from 14 studies involving 30 groups and 485 subjects. Subsequently, we performed a cross-sectional (n=116) and intervention (n=training group : 10 and control group : 6) studies. In both studies, ANS modulation was estimated by spectral analysis of HRV. In the meta-analysis and cross-sectional study, HR and natural logarithmic high frequency power (In HF power) were correlated with Vo₂max or peak oxygen uptake (peak Vo₂) . The significant negative correlations were found between HR and In HF power (meta-analysis and the cross-sectional study ; r² = 0.42 and 0.44, respectively) . Endurance training in the intervention study increased peak Vo₂ and resting In HF power, and decreased resting HR. These results strongly suggest that endurance training induces an increase in resting ANS modulation especially parasympathetic modulation. Furthermore, about half of the variability of resting HR can be accounted for by difference in parasympathetic modulation.

The purpose of this study was to clarify the effects of different frequencies of skipping rope on the elastic components of muscle and tendon in human triceps surae. Six male subjects performed ten rounds of skipping rope. Skipping tempos were with in a range of 100-170 skips per minute (SPM) . The vertical ground reaction force and the surface EMG of triceps surae muscles were recorded during each skipping round. Elastic components of muscle and tendon were estimated by Residual Time (RT : lag time difference between the vanishing point of muscle discharge and disappearance of EMG, and the end of the ground reaction force wave) and RTintegrate (integration of ground reaction force while RT still appears) . RT and RTintegrate at 100 SPM were the smallest values for all jump frequencies. On the other hand, integrated EMG (iEMG) at 100 SPM was the largest value for all jump frequencies. Although RT and RT_integrateprogressively increased as SPM was increased, iEMG correspondingly decreased. Rate in utilization of elastic components of muscle and tendon assessed by RT_integrateat 170 SPM corresponds to 150% at 100 SPM. These results suggest that the rate in utilization of the elastic components of muscle and tendon while skipping rope, depend on jump frequency.

The aim of this studv was to clarify the effects of water immersion on the cardiovascular recovery process following submaximal steady state exercise on land. Seven male subjects (23 yrs old) underwent experiments under four separate conditions on separate days (15 minutes of cycling exercise at 50% and 80% maximal oxygen consumption followed by 16 minutes of recovery in a sitting position in water and out of water) . Concerning conditions in water, mean water temperature was 29.4 degrees, and the immersion level was set at xiphoid. Mean room temperature in out of water conditions, and during all conditions of exercise, was 24.4 degrees. Oxygen consumption (VO₂), heart rate (HR) and blood pressure (systolic: SBP, diastolic: DBP) were measured under each condi tion. Mean blood pressure was calculated from SBP and DBP (MBP=1/3× ( SBP-DBP) +DBP) . Stroke volume (SV) was measured by Doppler echocardiography, and then cardiac output (CO=SV×HR), total peripheral resistance (TPR=NIBP/CO) and arteriaVmixed venous oxygen difference (a-v O₂diff=VO₂/CO) were calculated. In comparison with the same exercise intensity condition, there were no significant differences between recovery processes of VO₂, HR, SBP, DBP and MBP in and out of water. SV and CO were significantly higher (p<0.05) during the recovery process in water than out of water (SV: at 50 and 80% maximal oxygen consumption conditions, CO: at 80% condition) . The TPR and a-v O₂diff were significantly lower (p<0.05) during the recovery process in water than out of water at 80% oxygen consumption condition. These results indicate that water immersion facilitates circulating blood volume during the recovery process without increasing blood pressure, especially during recovery after high intensity exercise. Therefore, we suggest that increased left ventricular preload with immersion would be an important factor in cardiovascular regulation not only at rest but also during recovery after exercise.

The purpose of this study was to develop prediction models of sarcopenia in 1,894 Japanese men and women aged 18-85 years. Reference values for sarcopenia (skeletal muscle index, SMI; appendicular muscle mass/height², kg/m²) in each sex were defined as values two standard deviations (2SD) below the gender-specific means of this study reference data for young adults aged 18-40 years. Reference values for predisposition to sarcopenia (PSa) in each gender were also defined as values one standard deviations (1SD) below. The subjects aged 41 years or older were randomly separated into 2 groups, a model development group and a validation group. Appendicular muscle mass was measured by DXA. The reference values of sarcopenia were 6.87 kg/m² and 5.46 kg/m², and those of PSa were 7.77 kg/m² and 6.12 kg/m². The subjects with sarcopenia and PSa aged 41 years or older were 1.7% and 28.8% in men and 2.7% and 20.7% in women. The whole body bone mineral density of PSa was significantly lower than in normal subjects. The handgrip strength of PSa was significantly lower than in normal subjects. Stepwise regression analysis indicated that the body mass index (BMI), waist circumference and age were independently associated with SMI in men; and BMI, handgrip strength and waist circumference were independently associated with SMI in women. The SMI prediction equations were applied to the validation group, and strong correlations were also observed between the DXA-measured and predicted SMI in men and women. This study proposed the reference values of sarcopenia in Japanese men and women. The prediction models of SMI using anthropometric measurement are valid for alternative DXA-measured SMI in Japanese adults.

Objectives: This study aimed to determine the relationship between the number of board-certified physiatrists and the amount of inpatient rehabilitation delivered.Materials and Methods: We analyzed open data from 2017 in the National Database of Health Insurance Claims and Specific Health Checkups of Japan and compared the volume of inpatient rehabilitation services between prefectures to examine regional disparities. We also examined the relationship between the volume of rehabilitation services provided and the number of board-certified physiatrists.Results: The population-adjusted number of inpatient rehabilitation units per prefecture ranged from a maximum of 659,951 to a minimum of 172,097, a disparity of 3.8-fold. The population-adjusted number of board-certified physiatrists was 4.8 in the highest region and 0.8 in the lowest region, a disparity of 5.8-fold. The population-adjusted number of board-certified physiatrists was significantly correlated with the population-adjusted total number of inpatient rehabilitation units (r=0.600, P<0.001). Correlations were between the number of board-certified physiatrists and the number of rehabilitation units in cerebrovascular and orthopedic services, but not in cardiovascular, respiratory, or oncology services.Conclusion: Large regional disparities manifested in the amount of inpatient rehabilitation provided in Japan. An association was found between the number of board-certified physiatrists and rehabilitation units delivered. It may be necessary to train more BCPs in regions with fewer units to eliminate these disparities.

The purpose of this study was to develop prediction models of sarcopenia in 1,894 Japanese men and women aged 18-85 years. Reference values for sarcopenia (skeletal muscle index, SMI; appendicular muscle mass/height2, kg/m2) in each sex were defined as values two standard deviations (2SD) below the gender-specific means of this study reference data for young adults aged 18-40 years. Reference values for predisposition to sarcopenia (PSa) in each gender were also defined as values one standard deviations (1SD) below. The subjects aged 41 years or older were randomly separated into 2 groups, a model development group and a validation group. Appendicular muscle mass was measured by DXA. The reference values of sarcopenia were 6.87 kg/m2 and 5.46 kg/m2, and those of PSa were 7.77 kg/m2 and 6.12 kg/m2. The subjects with sarcopenia and PSa aged 41 years or older were 1.7% and 28.8% in men and 2.7% and 20.7% in women. The whole body bone mineral density of PSa was significantly lower than in normal subjects. The handgrip strength of PSa was significantly lower than in normal subjects. Stepwise regression analysis indicated that the body mass index (BMI), waist circumference and age were independently associated with SMI in men; and BMI, handgrip strength and waist circumference were independently associated with SMI in women. The SMI prediction equations were applied to the validation group, and strong correlations were also observed between the DXA-measured and predicted SMI in men and women. This study proposed the reference values of sarcopenia in Japanese men and women. The prediction models of SMI using anthropometric measurement are valid for alternative DXA-measured SMI in Japanese adults.

BACKGROUND: There is little data on the association between the lower nutrition represented by serum albumin levels and related factors in a general population. The present study aimed to determine whether the albumin level positioned as some kind of biomarker with frailty measures, trace elements, and an inflammation marker. METHODS: In 2018, we performed an epidemiological survey in 1368 subjects who resided in Tanushimaru, Japan, in which we examined the blood chemistry including albumin, trace elements, hormone levels, and carotid ultrasonography. Albumin levels were categorized into 4 groups (G1 [3.2-3.9 mg/dL], G2 [4.0-4.3 mg/dL], G3 [4.4-4.6 mg/dL], and G4 [4.7-5.3 mg/dL]). The participants underwent measurements of handgrip strength and were tested by asking to walk 5 m. Their cognitive functions were evaluated by the mini-mental state examination (MMSE). RESULTS: Multiple stepwise regression analysis demonstrated that albumin levels were significantly and independently associated with age (inversely), systolic blood pressures, estimated glomerular filtration rate (eGFR), MMSE score, frailty measures (handgrip strength), an inflammation marker (high-sensitivity C-reactive protein), hormones (growth hormone (inversely) and insulin-like growth factor-1), and trace elements (calcium, magnesium, iron, and zinc), with a linear trend. CONCLUSIONS Lower albumin levels, even in the normal range, were found to be related factors of frailty measures, trace elements, and an inflammation marker in a general population.
Aged ; Albumins/metabolism* ; Biomarkers/blood* ; Cross-Sectional Studies ; Female ; Frailty/physiopathology* ; Hand Strength/physiology* ; Humans ; Inflammation/blood* ; Japan ; Male ; Trace Elements/blood*