The purpose of this study was to investigate the circulation responses (heart rate (HR), systolic blood pressure (SBP) and second derivative of photoplethysmogram waveform index (|d/a|)) during 90 seconds continuous isometric contraction on trunk muscle. Subjects were 10 healthy male (22±1 years). Subjects performed 90 seconds continuous isometric contraction on Rectus Abdominus. Contraction intensity was 55.4±13.8% maximal voluntary contraction.HR and SBP were a significant increase after contraction beginning, immediately. |d/a| (one of the peripheral blood vessel contraction index) was a significant increase at 60 seconds after contraction beginning. After that, HR was an increase more, |d/a| showed a decline tendency. But, SBP was an increase more.The followings are suggestive by these results. When the contraction beginning, HR was increased immediately by central command, muscle mechano reflex and so on. The other hand, the peripheral blood vessel contraction was late by the accumulation of metabolism product from active muscle was late. When the prolong contraction time, the peripheral blood vessel was extension. But, SBP was increased more by increasing the cardio output, muscle tension and so on.

The aim of the present study was to investigate the consciousness among young people (n = 494) of training body part(s) by showing participants a picture of an exercise, through a questionnaire-based survey. Participants were shown a picture of a Back Squat, and were asked which body part(s) they felt was being trained in the picture. Participants who had no experience of doing squatting exercises (NO-SQUAT group, n = 102) and participants who were experienced in terms of doing squatting exercises and weight training under appropriate supervision (INSTRUCTED group, n = 146) were selected for the analysis. On seeing the picture, more than half of the NO-SQUAT group felt that the Back Squat was to train not only their lower body but also another body part(s); among these participants, approximately 70% felt that a Back Squat was appropriate to train their upper torso and arms too. Further, the NO-SQUAT group had made significantly fewer attempts to consciously train their gluteal and knee flexor muscles, and had made significantly more attempts to consciously train their upper torso and arms during the squatting exercises than the INSTRUCTED group had. These results suggest that to do exercises by referring to only a picture may result in the participants not properly understanding how the body part(s) should be trained during exercise. Therefore, to enhance the benefits of training, individuals need to be instructed, under appropriate supervision, on correct technique as well as knowledge about the exercise.

Objectives: This study aims to investigate the association between skeletal muscle mass index (SMI) and physical activity among female university students who had exercise habituation in junior and high school. Methods: The body composition of 120 Japanese female students was measured using the bioelectrical impedance analysis (BIA) method, and their physical activity level (PAL) was measured using a factorial method. Based on the ‘Dietary Reference Intakes for Japanese’ (DRIs-J), according to the Ministry of Health, Labour and Welfare, PAL (24-h energy consumption/basal metabolic rate) classifications were defined as low-PAL (PAL < 1.6), moderate-PAL (1.6 ≤ PAL < 1.9), and high-PAL (1.9 ≤ PAL < 2.2), respectively. Results: Individuals with low-PAL had a significantly lower SMI, especially for the lower limb muscles, than individuals with moderate-PAL or higher. More than 50% of the individuals with currently low-PAL corresponded or tended to correspond to the SMI cut-off value defined by the Asian Working Group for Sarcopenia or the 2017 National Health and Nutrition Survey of Japan. Therefore, more than half of the female students with currently low-PAL, even those with an exercise habituation in the past, corresponded to the cut-off value for muscle loss in sarcopenia diagnosis, particularly in the lower limbs. Conclusions These results suggest that it is important to maintain a moderate or higher level of physical activity in the DRIs-J classification, even for young women who used to exercise in the past, to maintain muscle mass accordingly.

The purpose of this study was to investigate the consciousness among young people (n = 1016) on training body part(s), using a questionnaire-based survey showing participants a picture of a single-joint exercise. The participants were shown a picture of knee-extension exercise (KNEE-EXT), and were asked to identify the body part(s) they felt were being trained. On seeing the picture, more than 90% of the participants felt that KNEE-EXT can train the anterior thigh part. However, more than 90% of the participants who had no experience doing KNEE-EXT felt that the exercise trained not only the anterior thigh part but also other parts, including the trunk, the posterior thigh, and the upper limb. Among those participants who had performed KNEE-EXT without the experience of strength-training under professional supervision, approximately 80% felt that the exercise was appropriate to train not only the anterior thigh but also other parts. These results suggest that performing exercises by referring to only a picture may result in the individuals not properly understanding how the body part(s) should be trained during exercise, even in single-joint exercises. Appropriate supervision is of even greater importance especially for strength-training beginners. Furthermore, even among participants who had an experience of exercise under professional supervision, approximately 60% had a similar response. Therefore, to enhance the benefits of exercises, individuals (even those who have had experience in training under professional supervision) should always be instructed under appropriate supervision on the correct technique and knowledge about the exercises.