ABSTRACT
The effects of voluntary exercise on resting systolic blood pressure and vascular lesions of stroke-prone spontaneously hypertensive rats (stroke-prone SHR) were investigated with and without 1 % saline loading. Forty male stroke-prone SHR aged 7 weeks were assigned to one of 4 experimental groups. Each consisted 10 animals ; sedentary control (S), sedentary with 1 % saline loading (SS), exercised control (E), and exercised with 1 % saline loading (ES) . Animals were sacrificed at the 5 th week. In the prehypertensive phase, resting caudal arterial systolic blood pressure was significantly lower in the E group than in the S group. However, after being loaded with 1 % saline, the ES group showed higher resting systolic blood pressure than those of the SS group. In addition, the ES group revealed severer renal, myocardial, and cerebrovascular lesions than those of the rest of the groups.
ABSTRACT
The purpose of this study was to observe the effect of training on morphological properties in the collagen fibers of tendons. Wistar strain rats at 7 weeks old were assigned to high speed endurance (H), moderate speed endurance (M), jump training (J) and control (C) groups. The amount of exercise for H group (speed at 30m/min for 60 minutes) and M group (speed at 17m/min for 75 minutes) was equalized according to the amount of oxygen consumed during training. As for the anaerobic training (J group), rats made high jumping form the standing position, wearing jacket with 50% of body weight, 50 times/day, which lasted for 4-5 minutes. The training period was designed for 5 days per week for 16 weeks.<BR>The follwing is a summary of the results obtained:<BR>1) Increases in fiber areas of both Slow-Twitch (ST) and Fast-Twitch (FT) fibers were observed in the H, M and J groups. The ST fiber area of H group was significantly larger than that of C group. Significant increase in FT fiber area was observed in both M and J groups.<BR>2) Hypertrophy of collagen fiber in gastrocnemius muscle tendon was observed in Hand M groups; especially, M group showed much larger increase than H group. It tended to be greater for J group as compared with C group.<BR>3) Collagen fiber area and diameter of tendon in plantar muscle were slightly larger for H and M groups relative to C group, but these differences were not significant.<BR>These results suggested that both types of aerobic training induced hypertrophy in the collagen fibers of the tendons and increased the tensile strength; especially, the group which trained longer hours induced the higher effect.