National Taiwan University of Sport mark

Research

*Research Highlights

     Sleep impairment is a common problem among older adults with women more likely having sleep difficulties than men. By contrast, exercise has a range of health benefits and has been found to be associated with improved sleep quality. However, previous research tended to focus on effects of moderate- or high-intensity exercise on sleep and generally limited to good sleepers allowing limited room for improvement due to ceiling and floor effects. A study conducted by Dr. Li-Jung Chen, Professor of Department of Exercise Health Science, in cooperation with Loughborough University, (UK) and National Changhua University of Education showed that a single session of light-intensity walking led to a modest reduction in sleep latency and improvement of sleep efficiency in older women with mild sleep impairment. The results were published in Journal of Clinical Sleep Medicine in 2019.
 
      This study is the first to assess the effects of an acute walking intervention with light-intensity on sleep quality in older adults with sleep impairment. It used a rigorous randomized design, a carefully monitored exercise session, and objective measurement of sleep. It could fill an important gap in literature and extend the understanding of effects of light-intensity exercise on sleep in ageing populations.
 
     In another study, Dr. Chen and her research team further explored the independent relationships between frequency, duration and intensity of walking, as well as total volume of walking, with sleep difficulty in older adults two years later. The results showed that total walking volume was negatively associated with subsequent sleep difficulty. It suggests that high amounts of walking (>10.5 METs) in later life might help to reduce risk of sleep difficulties among older adults. Among the walking parameters (frequency, duration, and speed), walking speed emerged as the most salient independent parameter in the explanation of subsequent sleep difficulty. This study provides further support for walking programs for older adults that involve working at least at moderate intensity and for more than 20 minutes as a means of improving sleep quality. The results were published in Journal of Sport and Health Science in 2018.

     Physical fitness is associated with good cognitive health in the general population. There is a paucity of longitudinal research investigating fitness and cognitive performance in people with schizophrenia. Dr. Li-Jung Chen, Professor of Department of Exercise Health Science, has conducted a prospective cohort study to examine the relationships between various components of physical fitness and subsequent academic performance over two years among 190 inpatients with schizophrenia. The results showed that better cardiovascular fitness at baseline was significantly associated with better attention, dexterity, and memory. However, the relationships dissipated after adjusting for baseline cognitive scores.
 
     This study suggests that in a cohort of people with established schizophrenia who already had evidence of cognitive dysfunction, better physical fitness was not associated with improved cognitive status over two years. However, to improve physical fitness at the onset of psychotic illness may have protective effect on cognitive functions in the future. The results were published in Psychiatry Research in 2018.

     We all have experienced the fatigue during exercise. The most common situations are the decline in muscle functions, so our movements become slower, and our muscular force become weaker. We also feel the heart racing toward the throat, and out of breath. In addition to the muscles, the brain is also affected by exercise. During exercise fatigue, athletes tend to make poor decisions, commit errors, or fail to perform perfect skills. The ‘feeling’ of fatigue is also developed in the brain. With the brain playing such a crucial role in exercise performance, Dr Chen-Kang Chang, Professor in Department of Sport Performance, has tried to alleviate the fatigue in the brain by nutritional supplements.
 
     Dr Chang and his research team have discovered that by consuming branched-chain amino acids (BCAA), citrulline, and arginine, the athletes may delay the fatigue in the brain during intensive exercise. The beneficial results included better cognitive function, skills, and physical performance.
 
     In a series of studies on different sports, Dr Chang and colleagues have shown that this combination of amino acids can prevent the decline in cognitive functions and skill performance after exhausting exercise. In a study published in 2016, Dr Chang’s research team investigated the reaction time in taekwondo athletes during 3 simulated matches. The researchers measured pre-motor reaction time, the time required for the brain to receive and process the visual signal, and send the direction to the working muscles. The researchers also measured the performance in dual-task, the ability to do 2 things simultaneously. The subjects took the supplements before the third match. After 3 matches, the pre-motor reaction time and dual-task performance were maintained in the supplemented group, while the performance was declined in the control group. In another study on college tennis players, Dr Chang and colleagues found that this combination of amino acids can help the athletes to maintain the ability to hit the balls to the corners of the court after 2 hours of simulated matches. In addition, the players were more able to hit the ball to the opposite direction of the opponent’s movement. On the other hand, the control subjects showed declined performance in both tests.
 
     In addition to cognitive functions, this combination of amino acids can also improve physical performance. In a study on male and female handball players, the subjects performed a 20-m sprint every 2 min for 30 times on 2 consecutive days to mimic the movement pattern of a handball match. The supplementation of BCAA and arginine improved the sprint speed on the second day, while the control group showed a slight decline in the performance. In another study on endurance runners who ran a 5000 m race on the first day and a 10000 m on the next day, the subjects who consumed BCAA, citrulline, and arginine ran significantly faster in both races. The latest study by Dr Chang’s team is in high school swimmers who swam a 50 m sprint for 8 times. The swimmers who consumed the supplements had faster time in the 8 sprints combined.
 
     BCAA are popular supplements among athletes of a wide variety of sports, mostly for their claimed functions in muscle growth and recovery. Dr Chang and his colleagues revealed that these amino acids can also influence brain function during exhaustive exercise. In addition, the best results can be obtained by taking arginine and citrulline together with BCAA. These 2 amino acids can help to reduce ammonia, resulted from BCAA oxidation during exercise. The timing for the supplementation is 1 hour before exercise, so that BCAA can reach their peak concentrations in the blood, recommended by Dr. Chang.

     Dr. Shih-Hua Fang, Professor in Department of Sport Performance, used saliva to assess the salivary parameters to evaluate the physiological responses of elite athletes during training, competition, and recovery periods. Mucosal immunity constitutes the first line of defense against pathogen invasion. Human saliva contains various kinds of proteins and peptides that protect against microbial infection, such as immunoglobulin A (IgA) and lactoferrin. Cortisol is a key indicator of stress stimulated in response to physiological and psychological stresses. Cortisol in saliva, mostly in the un-bound form, is representative to the biologically active cortisol in the blood. In addition, the free-radical scavenging activity exerted by salivary antioxidants can prevent oxidative damage to cells and tissues.
 
     In a series of studies, Dr. Fang reported that cumulative effects of prolonged intensive training suppressed immunity and increased cortisol in saliva in taekwondo athlete, weightlifters, and volleyball players. Intensive training combined with rapid weight loss further suppressed the immunity and increased cortisol in saliva in female taekwondo athletes. In addition, because of the “open window” of impaired immunity during the pre-competition period, the incidence of upper respiratory tract infection was significantly increased after the competition. Using saliva samples as the monitory method for recovery after the training can be convenient, fast, and accurate, explained by Dr Fang. This method is also much more appealing to athletes, compared to the traditional methods that rely on blood samples.

     Green tea is a non-fermented/oxidized tea that has a wide range of health benefits. It has antioxidative, anti-inflammatory, and immunomodulatory effects, mostly due to the high amounts of polyphenolic flavonoids, including epicatechin, epicatechin gallate, epigallocatechin and epigallocatechin gallate. A study conducted by Dr. Shih-Hua Fang, a Professor in Department of Sport Performance, showed that green tea consumption after intensive training significantly enhanced the salivary antibacterial capacity in male and female taekwondo athletes. Dr Fang has developed the protocol to use saliva samples as the monitory method for recovery after the training. Green tea consumption can help to prevent the decline in immune functions commonly seen after intensive training. It could prevent the “open window”, a period in which athletes are susceptible to upper respiratory tract infection (commonly known as cold) due to the reduced immune functions. In this study, the athletes drank 9 ml green tea per kg of body mass immediately after the 2-hour training session, equals to 22 mg catechins and 6 mg/ caffeine per kg body mass.
 
     In another study on male cyclists, Dr Fang also showed that drinking green tea after an intensive training session prevents the post-exercise decreases in testosterone and lymphocytes in the blood. It indicated that green tea may help to preserve the immune function and promote better recovery after intensive training. In addition to the regular post-exercise food such as carbohydrate and protein, green tea may be added the mix, especially after a heavy workout.

     Hamstrings muscle strain is a very common injury in athletes and active persons. It often occurs during sprinting or kicking. It is estimated that about half of the athletes had suffered from hamstring strain at least once. In addition, the re-injury rate of hamstring strain is higher than 50%. In other words, if you suffered the injury once, you have a high chance to get injured again in the same place.
 
     Most people will do some form of warm-up and stretching before exercise. But what kind of stretching is the most effective way to prevent hamstring strain? Dr Che Hsiu Chen, an Associate Professor in Department of Sport Performance, tried to answer this question in a recent study published in PLOS ONE. The results showed that jogging combined with dynamic closed kinetic chain stretching (Figure) had better results in increasing flexibility and maximal strength and decreasing stiffness in the hamstring, compared to jogging combined with open kinetic chain stretching or jogging alone. Moreover, jogging combined with dynamic closed kinetic chain also led to better joint position sense. Joint position sense is a measurement for activating the receptors in the muscles, such as the muscle spindles, by stretching. The jogging was performed on a treadmill at the speed of 6.4 km/hr with 1% grade for 5 min. The dynamic closed kinetic chain stretching contains one second down and one second up back to the starting position, six 15-second sets were performed with 15 seconds of rest between consecutive sets. A total of 48 repetitions (6 sets × 8 repetitions per set) of stretching were performed. Dr Chen pointed out that during the stretching, one can start with the knee slightly bended (10-15 degree), then slowly bent the upper body forward until reaching the end of the hip flexion range of motion while simultaneously extending the knee to stretch the hamstring muscles. The intensity of stretching should be less than the point of discomfort.
The dynamic closed kinetic chain
Figure: The dynamic closed kinetic chain

     In an article published in Nutrients in 2018, Dr Chih-Hui Chiu, Assistant Professor in Department of Exercise Health Science, revealed that high-intensity intermittent exercise can reduce plasma triglyceride concentrations on the next day. The exercise protocol is the popular Tabata workout, totaling 20 min. The workout is consisted of upper and lower body movements. Each move included 20 seconds of high-intensity exercise and 10 seconds of rest. When asked why investigating the changes in plasma triglyceride concentrations after a high-fat meal, Dr Chiu explained that high postprandial hyperlipemia can significantly increase the risks of cardiovascular disease and insulin resistance. Since plasma triglyceride concentrations can be increased up to 6 hours after a meal, most people spend most of their time at the postprandial lipemia state, Dr Chiu added. Therefore, how to effectively decrease postprandial triglyceride concentrations can has recently received considerable attention.
 
     This high-intensity intermittent exercise used in this study has become popular in recent years, mostly because it can reach similar results in improving cardiovascular and muscular fitness, compared to traditional endurance exercise and resistance training. Furthermore, this type of exercise usually requires less time, space, and equipment. Dr Chiu pointed out that this is one of the first studies to show that high-intensity intermittent exercise can reduce plasma triglyceride concentrations after a high-fat meal. This study also showed that high-intensity intermittent exercise is more effective in reducing plasma triglyceride concentrations, compared to burning the same amount of calories through walking. This study also pointed out that high-intensity intermittent exercise resulted in significantly higher fat-burning rate after the meal, compared to walking and control (no exercise). This study provided the evidence for one more health benefit of the popular high-intensity intermittent exercise.

    Developmental Coordination Disorder (DCD) is a motor skills disorder that affects children. DCD children are usually described as "clumsy" or "awkward" because they have difficult in simple motor activities such as tying shoes or going down stairs.
 
     Dr Sheng-Kuang Wu, the Dean of College of Sport Performance, is the pioneer in DCD children research in Taiwan. He and his colleagues have examined a wide range of health behaviours in children with DCD since 2000. In a 3-year longitudinal study, Dr Wu’s research team discovered that DCD children showed a significant long-term decline in flexibility and muscular strength, compared to normal children of the same age and gender. In addition, those who had lower fitness levels also showed worse motor coordination.

     In a cross-sectional study involving 2029 children aged 9-10 years, Dr Wu’s research team showed that DCD children more likely to be obese when compared to normal children. In addition, obese and overweight children performed worse in a balance test. A further investigation revealed that DCD children with balance problems were 228% more likely to be obese, compared to normal children.
 
     In another study by Dr Wu's research team, the posture stability in children was measured with an aiming task. The subjects maintained a laser beam within targets placed in the front or in the side. The results showed that DCD children had more difficult in controlling anteroposterior sway (to the front and back), leading to lower aiming performance to the side target. However, the mediolateral sway (to the right and left) appeared to be similar in DCD and normal children.
 
     The reasons for the delay in the development of motor skills and the difficulty in coordinating movements in DCD are still unknown. In most countries, the prevalence of DCD in children is about 5-6%. The prevalence in 7-8-year-olds in Taiwan is 3.5%, similar to other countries. However, the prevalence in Taiwan increased to 20.6% in 9-10-year-olds and 25.6% in 11-12-year-olds. DCD children are seldom noticed by the health professionals and school teachers. With the high prevalence of DCD, it is necessary to include regular physical activity that encourages development of motor skills and increases physical fitness in children, said Dr Wu.

     It is common for companies to gather ratings of customer satisfaction using online surveys. However, most companies simply use the scoring method, for example, a score of 10 meaning very satisfied while a score of 1 meaning very unsatisfied. Dr Yi-Ting Mai, an Associate Professor in Department of Sport Management, has developed an online survey system that can provide accurate quantity comparisons and dig out find potentially helpful information in customer satisfaction for feedback to the companies. The online survey is based on the theory of Importance-Performance Analysis (IPA) and Parasuraman, Zeithaml & Berry (PZB) model. The results were published in Electronic Commerce Research in 2014. “The survey can quantify the results of various dimensions of customer satisfaction. It can also alert the companies which dimensions need to be improved, which means a more efficient way to allocate resources to improve customer satisfaction” , said Dr Mai.

     One of the major modern medical issues, obstructive sleep apnea (OSA), particularly at moderate to severe levels, may potentially cause cardiovascular morbidity and mortality. However, the diagnosis of OSA is not easy because polysomnography, the gold standard tool, has limited availability and is time-consuming. An alternative and more time- and cost-efficient approach is to screen patients using clinical prediction models. Dr Yi-Ting Mai, associate professor in Department of Sport Management, has developed a simple and accurate prediction system for the diagnosis of OSA using decision tree algorithms. “The system is equipped with expert-based feature extraction technique and automatic feature selection capability. It has been validated to successfully screen Taiwanese patients for moderate to severe OSA. The hybrid method that integrates an expert-based feature extraction technique with decision tree algorithms performs better than other formula tested in this study”, explained Dr Mai. The system only requires age, gender, and average systolic blood pressure. The results were published in Journal of Medical Systems in 2014.