ABSTRACT
Mitochondria play a central role in energy production but also are the main cellular source of reactive oxygen species (ROS). It is widely believed that aging is related to the accumulation of oxidative molecular damage due to ROS. Aging also induces a decrease in muscle function. Recent studies indicate that caloric restriction and physical exercise suppress the decrease in muscle function though the maintaining quality of mitochondria. This review provides the current understanding of the influence of caloric restriction and exercise on mitochondrial quality control in skeletal muscle.
ABSTRACT
The discovery of microRNAs (miRNAs) and following studies reporting that miRNAs are stably present in the circulation, paved the way for possible use of miRNAs as biomarkers. Identification of circulating miRNAs that are functional upon delivery to the recipient cells, suggests miRNAs play roles in cell-to-cell communication as well as hormones and cytokines. This review provides a basic understanding of miRNAs and the current understanding of circulating miRNA as biomarkers and focuses on their putative roles and regulation under stressed conditions including physical exercise.<br>
ABSTRACT
Skeletal muscle is the dominant organ in locomotion and energy metabolism so that maintaining skeletal muscle function is a prerequisite for our health and independent living throughout the life. A loss or decrease in skeletal muscle function leads to increased morbidity and mortality through the development of secondary diseases such as metabolic syndrome, type 2 diabetes, obesity, cardiovascular and respiratory disease. Identifying mechanisms which influence the processes regulating skeletal muscle function is a key priority. The recent discovery of microRNAs (miRNAs) provides a new knowledge controlling skeletal muscle function. miRNAs suppress gene expression through either in inhibition of protein translation or in degradation of the mRNA transcripts through a process similar to RNA interference (RNAi). This review provides the current understanding in skeletal muscle miRNA biology and focuses on their role and regulation under physiological conditions with exercise.
ABSTRACT
The purpose of this study was to investigate the relation between alterations of salivary secretory immunoglobulin A (SIgA) and the occurrence of upper respiratory tract infections (URTI) in rugby football players.We examined the relationship between the onset of URTI and the daily alterations of SIgA levels in 32 male collegiate rugby football players (20.5±1.3 years) during summer training camp for 36 days.Total of 6 in 32 subjects had the appearance of URTI symptoms (18 %). SIgA secretion rate decreased significantly in the middle of training camp compared to the baseline (P＜0.05). Furthermore, SIgA secretion rate during the appearance of URTI (13.7±1.1μg/min) were significantly lower than that without symptoms (19.2±1.4 μg/min, P＜0.01). These results suggest that serial monitoring of SIgA may be useful to assess the risk status of URTI affection in athletes.
ABSTRACT
[Objective] The aim of this investigation was to evaluate salivary dehydroepiandrosterone (DHEA) responses during a competitive period among female football players.<BR>[Methods] Subjects were college female football players (n=9) . Saliva and blood samples were collected at 18 : 00 (6 : 00 pm) and the profile of mood state (POMS) was recorded during a period of normal training (Pre), 3 days of competition (Competition), and a recovery period (Post) . Levels of salivary DHEA, cortisol, and serum creatin kinase (CK), urea nitorogen (UN), were determined.<BR>[Results] The levels of salivary DHEA significantly increased during competition (2 nd days) compared with Pre (p<0.05), and significantly decreased after competition compared with Pre (p<0.05) . The levels of salivary cortisol significantly increased during the competition (2 nd and 3 rd days) compared with Pre (p<0.05) . Whereas it decreased after competition compared with Pre. The levels of serum CK significantly increased during the competition (2 nd days) compared with Pre (p<0.05) . The levels of serum UN did not change during the study. The fatigue score of POMS significantly increased during competition (2 nd days) compared with Pre (p<0.05) .<BR>[Conclusion] These data suggest that DHEA could be a useful endocrinological indicator for evaluating training status in female athletes.
ABSTRACT
The purpose of this study was to investigate differences between underwater and land-based exercise in leg muscle activity. Nine healthy males (mean age : 21.7±0.5 years, mean height : 173.4±2.2 cm) had electrodes placed on their left leg muscles (Tibialis Anterior ; TA, Medial Gastrocnemius ; MG, Soleus ; SOL, Rectus Femoris ; RF, and Biceps Femoris ; BF), and their muscle activity was measured during various exercises. The subjects performed six types of exercise such as the forward walk, backward walk, squat, calf raise, leg range, and one leg wave, both in the water (waist level) and on land. These exercises were categorized as 3 types of leg movement according to direction ; horizontal, vertical, and mixed movement.<BR>In the forward walk and backward walk, categorized as horizontal movements, the integrated electromyogram (IEMG) significantly increased during underwater exercise compared with on land. In the squat, as a vertical movement, the IEMG showed a similar change under both conditions. In the calf raise, as a vertical movement, and leg range and one leg wave, as mixed movements, the IEMG significantly decreased during underwater exercise compared with on land. These results suggest that leg muscle activity during underwater exercise is different based on the movement direction of the legs. In a word, it was apparent that movement in a horizontal direction underwater provides greater activity for leg muscles than on land; but movement in a vertical and/or mixed direction underwater provides less activity for leg muscles than on land. In prescribing an exercise program, it may be helpful to understand the differences between underwater and land-based exercise in leg muscle activity.
ABSTRACT
Infection is the major cause of health impairment in elderly persons. Immune function declines with age. In order to keep the elderly in good health, it is necessary to control the age-associated decline of their immune function. Components of a non-specific immune system arc neutrophils, macrophages and NK cells. A specific immune system is composed of T lymphocytes and B lymphocytes. T lymphocytes differentiate in the thymus. Age-associated atrophy of the thymus causes a decline in T lymphocyte function. It is essential in aging of the immune system. B lymphocytes produce immunoglobulin to act as antibodies. With aging, abnormal antibodies such as autoantibodies and monoclonal immunoglobulin increase, and the number of normal antibodies compared to foreign antigens decrease. Exercise influences the autonomic nervous system, hypothalamo-hypophyseal system, and immune system. Moderate exercise enhances immune function, and severe exercise causes immune function decline. Immune function declines after a severe single bout of exercise, and an “open window” of infections occurs. Appropriate exercise training may improve immune function. Recently, it was shown that exercise training for one year increased the contents of secretory immunoglobulin A in saliva in elderly persons. This result suggests that long-term exercise training improves immune function in elderly persons.
ABSTRACT
The purpose of the present study was to investigate the effects of long-term exercise training on immune function in elderly individuals. This study was conducted on 27 sedentary subjects including 7 males and 20 females aged 66.1±4.2 yrs. (range of 60 to 77 yrs.) who participated in a 12-month exercise program. The subjects attended the exercise program 4.4 ± 1.7 times per month. Peripheral blood samples were taken prior to, and at 5 and 12 months during the exercise training program. Each lymphocyte subset (natural killer: NE, T, cytotoxic T: Tc, helper T: Th, memory-Th and NKT) count in the samples was measured using flow cytometry. Results indicated that NE and Tc cell counts were not significantly altered. Whereas, T and Th cell counts were significantly elevated after 12 months, and memory-Th and NET cell counts were significantly elevated after 5 and 12 months of exercise training. These results suggest that long-term exercise training may be a stimu lus to increase and or maintain immune function in elderly individuals.
ABSTRACT
[Objective] The purpose of this study was to determine whether icing treatment has an effect on muscle reaction time and functional performance of a sprained ankle. [Methods] Subjects were six persons (healthy group) and six persons who had an acute ankle sprain (patient group) . Anterior talar translation and talar tilt of the six patient group were evaluated by the stress X-ray measure. Ice treatment was applied for 20 minutes. [Results] The following points were clarified : 1) Reaction times of peroneus longus (PL) and peroneus brevis (PB) for the sprained ankle group (SA) were significantly longer than those for the non-sprained ankle group (NA) (p<0.05) . Length of time of standing on one leg with closed eyes for SA was significantly shorter than for NA (p<0.05) . 2) After icing treatment, reaction time of PL for SA tended to be shorter. Furthermore, PB significantly decreased after icing treatment (p<0.05) . Side-steps for SA were significantly increased after icing treatment (p<0.05) . 3) Reaction times of PL and PB for NA significantly increased after icing treatment (p<0.05) . Standing on one leg with closed eyes for NA significantly decreased after icing treatment (p<0.05) . [Conclusion] It was shown that icing treatment of a sprained ankle leads to a shorter muscle reaction time and an increase in the number of side-steps. Therefore, it was concluded that icing treatment of a sprained ankle might be able to improve incapacitated neuromuscular function and functional performance by acute trauma.
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[Objective] The aim of this investigation was to evaluate serum steroid hormone responses to acute resistance exercise. [Methods] Subjects were young healthy males (n=6) and females (n=6) . Each group performed three sets of 10 leg press and 10 bench press exercises at an intensity of their individual 10-repetition maximum (1ORM), with 1 min rest between sets. Blood samples were collected before (Pre-Ex) and immediately following the exercise (P0), 30 mm (P30), 60 mm (P60), and 24 hours (P24h) after the exercise. Levels of blood lactate, serum testosterone, dehydroepian drosterone sulfate (DHEAS) and cortisol were determined. [Results] The levels of blood lactate in males and females significantly increased at P0 and P30 compared with Pre-Ex (p<0.05) . In males, the serum level of testosterone significantly increased at PO (p<0.05), whereas in females, it significantly decreased at P0, P30, P60, P 24 h. (p<0.05) . The level of DHEAS significantly increased at P0 in both males and females (p<0.05) . [Conclusion] The change in the level of testosterone was different between males and females, but that of DHEAS showed a similar pattern for both sexes. The data suggest that DHEAS could be a useful indicator for evaluating the anabolic status of acute resistance exercise in females.
ABSTRACT
It is generally accepted that secretory immunoglobulin A (sIgA) is a major effector of local immunity in the oral cavity. The salivary sIgA level is known to be temporarily decreased after an acute single bout of intense exercise. On the other hand, the effect of continuous exercise training on salivary sIgA has been controversial. In the present study, we collected timed saliva samples from collegiate kendoists using the reliable saliva collection method that has already been reported. The collection was performed before, during and after a traditional high-intensity 10-day training camp during the coldest part of the winter. We investigated the effect of repetitious intense exercise training on resting sIgA levels in saliva.<BR>The subjects were 19 males and 8 females (age: 19.9±0.5 years) who took part in the camp. We obtained saliva samples before the camp, on the first and the 10th days of the camp, and 4 and 10 days after the camp at 5 p. m. The concentration of sIgA was measured by ELISA, and the sIgA secretion rate was calculated.<BR>The resting sIgA secretion rate decreased significantly during the camp. It remained at a lower level 4 and 10 days after the camp compared to the initial level, although it tended to recover gradually. Prolonged suppression of the resting sIgA secretion rate during a traditional winter kendo training camp might be induced by repetition of high-intensity training.
ABSTRACT
To investigate the effect of intense exercise on immunological factors in saliva, we measured secretory immunoglobulin A (sIgA), lactoferrin and fibronectin. We used a reliable saliva collection method that has already been reported. Timed saliva samples were obtained from 16 healthy young males. Samples were collected before, immediately after, 1 day after and 5 days after endurance running (42.195 km) . The concentrations (μg/ml) of sIgA, lactoferrin and fibronectin were measured by ELISA, and the secretion rates (μg/min) of each were calculated. Immediately after the exercise, the concentration of total protein in saliva increased significantly, but the sIgA secretion rate decreased to 53%. The secretion rates of both lactoferrin and fibronectin did not change significantly. The local immune system plays an important role in mucosal surface defense against upper respiratory tract infection. The sIgA level in the oral cavity was temporarily decreased after intense exercise. A decreased sIgA secretion rate might partly explain the increased susceptibility to upper respiratory tract infection after endurance exercise.
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.