We investigated the biomechanical and physiological characteristics of walking on a sandy beach and in a forest. Ten healthy subjects (aged 50 - 69 years) with average aerobic exercise ability walked on the following three courses, each 100-m long: concrete road, sandy beach and forest road. Subjects walked 300 m along each course. Various biomechanical and physiological parameters were measured. Significant differences were found in the following biomechanical data (p < 0.05): walking speed (concrete > beach ≈ forest), step length (concrete > beach ≈ forest), cadence (forest < beach ≈ concrete), shock load to the knee at heel contact (beach < concrete ≈ forest) and its variability (concrete < beach ≈ forest), activity of the tibialis anterior at heel contact (concrete > beach ≈ forest), activity of the peroneus longus at heel contact (forest > concrete ≈ beach), and activity of the triceps surae just before swing phase (forest < concrete ≈ beach). In physiological data, heart rate was within the range for aerobic training. Heart rate and calorie consumption in the 300-m walk were lower for concrete than for the other courses. In all courses, rating of perceived exertion was lower than “somewhat hard” and maximal blood pressure was within a safe range. These biomechanical and physiological characteristics of walking on a sandy beach and in a forest were discussed in relation to health maintenance and promotion.
Salivary Chromogranin A (CgA) is active in the sympathetic nervous system, and it is useful for detectingemotional stress. Therefore, it can be used as an indicator of mental load. This study examined the possibility of using salivary CgA as a biological marker indicating individual emotional personality traits. Scales for measuring mental health including anxiety and depressive symptoms were also administered. Saliva of university student participants (n = 53, 22 men and 31 women, mean age, 20.3 ± 1.2) was collected and SDS, STAI, and GHQ28 were administered to participants. The results indicated a negative correlation between salivary CgA and SDS (p < .01). Moreover, in women salivary CgA concentration of SDS-high-group was significantly lower than that of SDS-low-group (p <. 01). Furthermore, salivary CgA had a negative correlation with SDS. It was indicated that salivary CgA was related to SDS and that it might detect just individual traits of depression, based on anxiety and other neurotic symptoms.
Relationships among mental preparation, near-infrared spectroscopy-derived measures of muscle oxygenation and cognitive performance have not been fully established. We concomitantly measured concentrations of oxyhemoglobin (oxyHb), deoxyhemoglobin and total hemoglobin in the forearm flexor muscle, skin blood flow and cardiovascular responses during a preparatory period followed or not by the Stroop test (ST) in eight healthy individuals. The relationship between oxyHb levels in the forearm muscle and reaction time in the ST was also analyzed. Levels of oxyHb in the bilateral forearm muscles were significantly higher during preparation for the ST. Furthermore, the mean reaction time at the start of the ST showed significant negative correlation with oxyHb in the forearm muscles during preparation for the ST. These results indicate that mental preparation for the Stroop test evokes an increase in muscle blood flow in bilateral forearm muscles, resulting in the activation of cognitive function.