ABSTRACT
We carried out tests of visual functions and evaluated the effects of the correction of visual acuity on kinetic visual acuity (KVA) in 21 high school rugby players. KVA during sports activities was highly correlated with binocular vision (r=0.719, p<0.0001) and static visual acuity (SVA) (r =0.798, p<0.0001) . When binocular vision, SVA, and KVA during sports activities were compared after correction, they all significantly improved after correction (binocular vision: 0.78±0.39→1.46 ±0.26, p<0.0001 ; SVA : 0.86±0.48→1.31±0.25, p<0.01 ; KVA : 0.54±0.350.75±0.20, p <0.05) . Moreover, significant negative correlations were observed among binocular vision, SVA, and KVA and the percent improvement after correction (r=-0.755, r=-0.848, r=-0.829, respectively ; all p<0.001) . The percentage of KVA to SVA was 64.0±21.7% during sports activities and 59.1±16.7% after correction decreasing slightly with correction, though not significantly. Therefore, KVA, which plays an important role in sports activities, improved as SVA improved, and poor KVA is thought to improve to an adequate level by correction of visual acuity. However, the effect of a correction was smaller in KVA than in SVA, and KVA deteriorated with over-correction in some players. Further studies are needed concerning the criteria for correction to obtain good KVA and the relationship between correction and training.
ABSTRACT
The effects of endurance training and detraining on cardiac autonomic nervous system activity were studied by using the power spectral analysis of heart rate (HR) variability. Twenty-one sedentary male subjects were trained for 8 weeks using cycle ergometer exercise [70% of maximal oxygen uptake (VO<SUB>2</SUB>max), 60 min, 3.4 times/wk] . Resting HR for 5 min was recorded before the training, after the 8-week training period, and after the 2-week and 4-week detraining period. The indices of cardiac parasympathetic and sympathetic nervous system activity were determined by Mem-Calc method, as the high frequency power (HF : 0.15-0.50 Hz) and the ratio of the low frequency power (LF : 0.04-0.15 Hz) to the HF (LF/HF), respectively. The VO<SUB>2</SUB>max after the training and 4 weeks detraining period were significantly higher than the initial value (before training : 41 ± 1 ml/kg/min ; after training: 48±2, <I>P</I><0.0001; after detraining: 46±2, <I>P</I><0.001) . The HF was significantly in-creased by the training (<I>P</I><0.05), and maintained the increased level for the 2-week detraining period (before training : 6.4±0.3 In ms<SUP>2</SUP>; after training: 7.0±0.2, <I>P</I><0.01; after 2-week detrain-ing: 7.0±0.2, <I>P</I><0.05) . The increase in the HF, however, disappeared after the 4-week detraining period (6.8±0.31n ms<SUP>2</SUP>) . The LF/HF did not show any significant changes during the training and detraining period. These results suggest that an endurance exercise with moderate intensity enhan-ces cardiac parasympathetic nervous system activity, but not cardiac sympathetic nervous system activity. The enhanced cardiac parasympathetic nervous system activity, however, may regress rapidly during detraining period.
ABSTRACT
The authors hypothesized that habitual physical exercise and aortic distensibility would be the major factors which influence systolic blood pressure. This study was designed to analyze the relationships among systolic blood pressure (SBP) and parameters determined at medical checks, including age, diastolic blood pressure (DBP), aortic pulse wave velocity (APWV) index (APWVI : APWV standardized by the diastolic blood pressure), plasma lipid profiles (IC, TG), plasma glucose during an oral glucose tolerance test (2 h-OGTT), percentage body fat (%Fat), cigarette smoking habit (Cigarettes), alcohol consumption (Alcohol), and physical activity index (PAI) using a questionnaire, in 678 males aged 30 to 69 years, who visited a hospital for a thorough medical check-up. For analysis of factorial structure in the subjects, principal factor analysis was applied to the correlation matrix which was calculated with 12 variables. Correlational analysis and path analysis were applied to confirm the hypothetical model. The results demonstrated that DBP and APWVI were the major factors which significantly affected the SBP. The PAI was significantly and inversely correlated not only with the APWVI, but also with %Fat, which was significantly and positively correlated with the DBP. In conclusion, aortic wall stiffness may be an independent factor in the manifestation of systolic hypertension, and habitual physical exercise may decrease the SBP through direct reduction of aortic wall stiffness and indirectly decreasing the DBP.
ABSTRACT
It is generally accepted that visually impaired individuals generally have a low aerobic capacity, which may be partly attributed to a lack of physical activity, and have hypothesized that their response to exercise may differ from that of normal-sighted people. In this study, we investigated the effect of exercise on local immunity in the oral cavity in 24 visually impaired males (n=8 ; totally blind group, n=16 ; partially sighted group) and 8 normal-sighted males. The subjects performed submaximal graded bicycle ergometer exercise to an intensity of 75% heart rate max for 12 min. Before and immediately after exercise, we collected timed saliva samples and measured secretory immunoglobulin A (sIgA) .<BR>The totally blind group had lower levels of aerobic capacity and a lower sIgA secretion rate compared to the partially sighted and sighted groups. Immediately after exercise, the sIgA secretion rate tended to increase in the totally blind group.<BR>It is suggested that the exercise-induced response of local immunity in the totally blind group differed from that in the other groups.