Abstract
Background
Recent studies demonstrate a slowdown in deterioration of cognitive functioning in old age through aerobic training. There is evidence that the combination of aerobic, balance, and coordination exercises leads to an improvement or maintenance of cognitive functions. Such age-related exercises can especially be found in East Asian martial arts. The purpose of the current study is to verify whether karate training for older adults improves cognitive functioning and, if an improvement can be found, which cognitive fields are influenced.
Methods
Eighty-nine older women and men (mean age: 70 years) participated in this study. The participants were randomized into 2 intervention groups (karate group and fitness group, duration of intervention: 5 months) and a control group. All participants had to accomplish a cognitive test battery before and after the intervention. In a secondary study the karate group had an additional intervention for another 5 months.
Results
The results show that there is a significant improvement in motor reactivity, stress tolerance, and divided attention only after the 5-month karate training period. Additionally, the results of the secondary study indicate further improvements after 10 months.
Conclusion
The 5-month karate training can help to enhance attention, resilience, and motor reaction time, but a training period of 10 months is even more efficient.
Keywords
Cognition
Divided attention
Karate
Motor reactivity
Older adults
Physical exercise
1. Introduction
It is a fact that some cognitive functions decrease while others remain unaffected during aging.1, 2, 3 According to Glisky3 cognitive functioning contains basic cognitive functions (attention, working memory included speed of information processing, long-term memory, perception) on one hand and higher-level cognitive functions (speech and language, decision making, executive control) on the other hand.
While “crystallized” intelligence (e.g., factual knowledge and experience) retains, the “fluid” intelligence (e.g., working memory and processing speed) deteriorates, which also has an effect on other cognitive areas (e.g., word fluency and problem-solving ability).4The deterioration in cognition, based on biological degradation processes, especially affects the velocity and flexibility of information processing and memory retention.3Schapkin4 suggests that neuroplasticity can activate additional areas of the brain which reduce the error rate and increase the reaction time.
Another important aspect is the relation between the decrease of cognitive abilities and the risk of falling.5 Liu-Ambrose et al.6 propose that improved cognitive function, especially executive functions and associated functional plasticity, may be an important mechanism to reduce falls in older adults. But this proposal has not been accepted yet.
A growing number of studies have analyzed the influence of special sports interventions on cognitive abilities in older age. Meta-analyses were carried out by Colcombe and Kramer,7 Smith et al.,8 Price et al.,9 and Zhao et al.,10 who summarize that physical activity of older persons can improve cognitive performance11 and decrease the risk of dementia in older people.12 Findings from cross-sectional, longitudinal, and intervention studies with healthy older adults, frail patients, and persons suffering from mild cognitive impairment and dementia lead to the conclusion that physical exercise is a promising non-pharmaceutical intervention to prevent age-related cognitive declination and neurodegenerative diseases.13
In particular, aerobic endurance training has a significant effect on processing speed, attention, and executive function, but only a minor one on working memory.1, 8, 14, 15, 16 A possible reason is given by Colcombe et al.,17 who, in an intervention study with persons aged 60–79 years, found out that the brain volume (white and gray matter) increases significantly after an aerobic training in comparison to a stretching training. Based on results of interventional studies Gregory et al.12 show that endurance exercises increase the volume of special brain areas (particularly hippocampi).
Some studies give indications regarding the effect of other training programs than aerobic ones on cognitive performance. Hötting et al.14 studied middle-aged adults (40–56 years) and found different effects between an aerobic endurance training (cycling) and a training with stretching and coordination on cognitive functioning, which both lead to advances in memory. The cardiovascular fitness correlated more with episodic memory while stretching/coordination training particularly improved selective attention.
However, it should be considered that the heterogeneity of the subject groups (educational level, socioeconomic status) makes comparisons difficult.1 This can be seen by the results of the meta-analysis by Price et al.,9 based on publications between 2006 and 2008, which show a great heterogeneity between the subject groups with regard to training intensity, educational level, and socioeconomic status.
Further research is needed to understand the impact of other forms of exercises as well as the intensity–response relationship that controls the positive impact of exercise on brain functions.13
Up to now, the influence of duration, frequency, or intensity of exercises on cognitive performance could not be explained. It is an open issue whether physical exercises with a higher level of motor complexity, in comparison to relatively simple exercises, influence more cognitive functions, brain physiology, respectively. Studies of complex and simple motor tasks are therefore required.
Boyke et al.18 studied the implication of motor learning (in this case 3-ball cascade juggling) of older people (mean age: 60 years) on brain structure. On the basis of magnetic resonance imaging, they found that there was an increase of gray-matter changes in the middle temporal area of the visual cortex on the left side of the hippocampus and in the nucleus accumbens bilaterally.
Our study focuses on East Asian sports including whole-body exercises on a high coordinative level and investigates a possible effect on the cognitive performance of older adults. Chang et al.19 postulate that Tai Chi improves cognitive abilities in older adults. The study by Dechamps et al.20 of frail older adults confirms that a Tai Chi training program (twice a week, 30 min) enhances the physical and mental state through the interaction of cognition and action.
Wagner21 studied the effect of a modified karate training of adults aged older than 50 years on physical and cognitive abilities and well-being. His findings show advances in short-term and procedural memory. He therefore concludes that appropriate karate training for older adults reduces fall risk and improves the subjective quality of life.
The study by Jansen and Dahmen-Zimmer22 analyzed explicitly the impact of karate training, including exercises with more stringent requirements in coordination, on the well-being and cognitive abilities of older adults. The results show only trends of improvements in memory performance but significant improvements in well-being. It should to be noted that the training group contained only 12 subjects and the interventions had a duration of only 3 months.
Marie-Ludivine et al.23 examined fifteen 50-year-old men in regard to the impact of karate training on healthy well-being, balance, aerobic capacity, and cognitive abilities. However, a control group without intervention is missing. The results show that a karate training over 12 months has a positive influence on mood and perception of physical health. This was confirmed by a better postural control, improved performance on objective physical testing, and shorter reaction time of the non-dominant hand.
From all these research findings we can conclude that a combination of aerobic, balance, and coordination exercises leads to an improvement or maintenance of cognitive functions. These age-related exercises are used in East Asian martial arts, e.g., Tai Chi, taekwondo, Kung Fu, and karate. From these we selected karate, because techniques can exercise relatively slow, weapons may not be used and therefore the risk of injuries for older adults is low. The benefits of karate sport for older adults compared to other martial arts sports are discussed.23 In summary, karate sport is characterized by aerobic fitness,24 coordination between arms and legs as well as between the right and left sides of the body at a relatively high level, continuous learning of new movements and orientation.
We expect that age-appropriate karate training helps to prevent cognitive decline in older age. Therefore, the aim of the present intervention study is to analyze the influence of age-appropriate karate training on several fields of cognition (common cognitive performance, motor reactivity, reactive stress tolerance, and divided attention) of older adults. We hypothesize that age-related karate training has a positive impact on common cognitive functioning, motor reactivity, reactive stress tolerance, and divided attention in older adults compared to common fitness training or even without special sports programs.
In the primary study we therefore included a second sports intervention group (common fitness training) and a control group without any specific intervention program. The interventions were carried out over 5 months. Another aim was to analyze if there are further changes in cognitive functioning in the karate group. Therefore an additional 5-month karate training was accomplished for the karate group after the common intervention program in a secondary study.
2. Methods
2.1. Study design and participants
The randomized controlled study was carried out at the Department of Sport Science and at the Department ofOccupational Medicine of the Otto-von-Guericke-University Magdeburg and was approved by the Otto-von-Guericke-University Ethics Committee. A written informed consent was obtained from each participant.
The sample size was calculated to detect large effects (in the sense of Cohen’s d ≥ 0.8) with a power of 80% for 2-sided tests at level α = 0.05 when comparing the 2 treatment groups.
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