Use of sports tourism to motivate older adults to maintain increased aerobic exercise capacity and reduced arterial stiffness after supervised training: a non-randomized controlled trial / 体力科学

Habitual aerobic exercise decreases arterial stiffness, a risk factor for cardiovascular disease, and increases aerobic exercise capacity. Exercise habits can be difficult to maintain over time. We sought to determine if the prospect of participating in a sports tourism event (mountain climbing) helped older adults maintain increased aerobic exercise capacity and decreased arterial stiffness after a supervised training program. Forty community-dwelling middle-aged and older individuals were divided into training (n=20) and control (n=20) groups. The training group participated in six weeks of face-to-face exercise intervention (walking, 60%–75% of age-predicted maximal heart rate, 35–50 min/day, 1 day/week) and was additionally offered home-based walking (45 min/day, 2–4 days/week). During the same period, the control group was asked not to change their lifestyle. In the last session of the exercise program, we announced a mountain climbing event planned for six months in the future. The participants were encouraged to maintain their exercise habits leading up to the event. Arterial stiffness (brachial-ankle pulse wave velocity) and maximal oxygen uptake were measured before and after the six-week intervention and two weeks before the mountain climbing event. In the training group, arterial stiffness decreased, and maximal oxygen uptake increased after the intervention; these improvements were successfully maintained until the mountain climbing event. These parameters did not change significantly in the control group. Sports tourism may motivate older adults to maintain their exercise habits after a supervised training program.

Acute effects of static stretching on flexibility: A comparative study among students to identify the best timing to improve flexibility / 体力科学

Flexibility is an important factor of physical fitness to prevent sports injuries. However, the best timing to improve flexibility during the growth and development period in children has been unclear. To compare the acute effects of static stretching on flexibility between school-grade children in the growth and development period, we measured the hip joint flexion range of motion (RoM) by using straight leg raising (SLR) before and after static stretching (6 exercises, 15 seconds, 2 sets) in 50 young male children aged 7 to 13 years (the second grade of elementary school to the first grade of junior high school). The RoM in SLR significantly increased after stretching versus that before stretching in all subjects. This positive improvement of RoM was statistically significant among all grade levels. Notably, the change rate in RoM after stretching was significantly greater in the fourth grade of elementary school than in the other grades. The rate of height increase during the past year was lower in students from the fourth grade than in students from the second grade of elementary and the first grade of junior high school. These results suggest that flexibility training is more effective during the slow-down period of growth and development in young male children.

EFFECT OF EXERCISE TRAINING ON SERUM HIGH-SENSITIVITY C-REACTIVE PROTEIN CONCENTRATION IN HEALTHY MIDDLE-AGED AND ELDERLY SUBJECTS / 体力科学

High-sensitivity C-reactive protein (CRP) is a novel risk factor for coronary artery disease. It is well known that body weight loss is effective in reducing serum CRP concentration ; however, the effect of exercise training on serum CRP concentration has not been fully elucidated. The purpose of this study was to examine the effect of a 24-week exercise training program on serum CRP concentration in 169 healthy middle-aged and elderly subjects (65.9±6.4 years). Each subject underwent baseline testing (peak oxygen uptake, daily physical activity, body weight, and serum CRP levels), and repeated these tests on completion of the training program. The subjects were classified into 2 groups based on initial CRP levels : normal<1.0 mg/L, n=139, and high≥1.0mg/L, n=30. On completion of the program, both daily physical activity and peak oxygen uptake increased significantly (+33.9±72.4%, p<0.0001, +5.4±14.7%, p=0.014, respectively). However, body weight did not change significantly. In addition, CRP levels of the entire group did not change significantly. However, CRP levels significantly decreased among the high baseline CRP group (from 1.82±0.81 mg/L to 0.98±0.59 mg/L, p<0.0001). It was concluded that serum CRP levels are reduced without body weight loss in response to exercise training in healthy middle-aged and elderly subjects with high initial CRP levels.

BASAL GENE EXPRESSION OF VASCULAR ENDOTHELIAL GROWTH FACTOR-RELATED TRANSCRIPTIONAL FACTORS IN RAT SKELETAL MUSCLE DIFFERS BETWEEN SLOW AND FAST FIBER TYPES / 体力科学

Skeletal muscle is comprised of multiple fiber types. Slow-twitch oxidative muscle fibers have greater capillary density compared with fast-twitch glycolytic fibers of skeletal muscle. To gain insight into the molecular mechanism underlying the difference of capillary density, we investigated whether the basal gene expression of vascular endothelial growth factor (VEGF), a major angiogenesis-related factor, and its transcriptional factors (hypoxia-inducible factor-1α, transforming growth factor-β1, c-jun, and c-fos) differs between these two fiber types of rat skeletal muscle. The mRNA expression of VEGF and its transcriptional factors was significantly higher in slow type fiber of muscle (soleus muscle) compared with fast type fiber of muscle (plantaris and tibialis anterior muscles). These results suggest that the difference of basal gene expression of VEGF and its transcriptional factors between slow and fast fiber types of skeletal muscle may partly contribute to the difference in capillary density between these two fiber types.

GENDER DIFFERENCES IN MUSCLE FORCE AND OXYGENATION RECOVERY FROM INTERMITTENT HANDGRIP EXERCISE / 体力科学

To investigate a relationship between gender differences in recovery from skeletal muscle fatigue and muscle oxygenation, we examined whether there is a difference in oxygen supply and consumption of the working muscles after intermittent handgrip exercise between young males and females using near-infrared spectroscopy (NIRS). Healthy young subjects (25.8±3.9 years ; males, n=10 ; females, n=10) repeated static maximal voluntary contractions (MVC) with a handgrip for 5 seconds followed by 5 seconds rest for a period of 4 minutes in Study 1. The MVC force was measured before, each minute during the handgrip exercise, and 2, 5, and 10 minutes following the exercise. In Study 2, the selected 10 subjects (males, n=5 ; females, n=5) performed the same exercise and their total- and deoxy- hemoglobin/myoglobin level was measured using the venous occlusion NIRS method; and O₂ supply index (OSI) and O₂ consumption index (OCI) calculated before and after the exercise. In Study 1, females exhibited higher %MVC force at the end of the exercise and during the recovery period than males (p<0.05). In Study 2, the %OSI was significantly lower in females than in males at 5 and 10 minutes in the recovery period (p<0.05), but no significant differences were detected in %OCI. Furthermore, %MVC of the recovery period correlated with %OCI of the recovery period in females (r=0.724, p=0.015), but not in males. These findings suggest that female working muscles can convert consumed oxygen more effectively after an intermittent handgrip exercise, and therefore, be able to recover muscle force faster.

EFFECT OF PHYSICL ACTIVITY ON SYSTOLIC BLOOD PRESSURE IN ELDERLY HUMANS / 体力科学

Arterial compliance progressively decreases with aging. This aging-induced reduction of arterial compliance causes an increase of systolic blood pressure (SBP), whereas regular exercise increases arterial compliance. We hypothesized that an increase in daily physical activity (DPA) produces a beneficial effect on systemic arterial compliance (SAC ; an index of central arterial compliance) and this phenomenon could decrease SBP in the elderly. We investigated the relationship among DPA, SAC, SBP, diastolic blood pressure (DBP), and some other risk factors for cardiovascular and/or cerebrovascular events (total cholesterol, HDL-cholesterol, and HOMA-R) cross-sectionally in 127 elderly persons (42 male, 85 female : aged 74±4 years) . The DPA was estimated by expended calories using an accelerometer. The SAC was calculated from a finger pulse pressure waveform recorded by using PORTAPRES ; and stroke volume obtained from the same pressure waveform based on the volume-clump method. The analyses demonstrated that SBP was directly and decreasingly affected by SAC, and that DPA had an increasing effect on SAC. Furthermore, SBP was directly and increasingly affected by DBP, and DBP was directly and decreasingly affected by both SAC and DPA. Therefore, it is considered that DPA may have suppressive effects on the rise of SBP through the indirect effects of changing SAC and DBP. These findings suggest that an increase in DPA could improve the age-induced reduction of arterial compliance and rise of SBP in elderly humans.