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Societies 2014, 4, 161–179; doi:10.3390/soc4020161
societies
ISSN 2075-4698
www.mdpi.com/journal/societies
Review
The Effectiveness of Hard Martial Arts in People over Forty:
An Attempted Systematic Review
Gaby Pons van Dijk 1,*, Pieter Leffers 2 and Jan Lodder 1
1 Department of Neurology, University Hospital Maastricht and School for Mental Health and
Neuroscience (MeHNS), 6202 AZ Maastricht, The Netherlands; E-Mail: j.lodder@mumc.nl
2 Department of Epidemiology and School for Public Health and Primary Care (CAPHRI),
Faculty of Health, Medicine and Life Sciences, Maastricht University Medical Centre,
6229 ER Maastricht, The Netherlands; E-Mail: p.leffers@maastrichtuniversity.nl
* Author to whom correspondence should be addressed; E-Mail: g.ponsvandijk@mumc.nl;
Tel.: +31-614-481-365; Fax: +31-433-877-055.
Received: 7 January 2014; in revised form: 3 April 2014 / Accepted: 22 April 2014 /
Published: 30 April 2014
Abstract: The objective was to assess the effect of hard martial arts on the physical fitness
components such as balance, flexibility, gait, strength, cardiorespiratory function and
several mental functions in people over forty. A computerized literature search was carried
out. Studies were selected when they had an experimental design, the age of the study
population was >40, one of the interventions was a hard martial art, and when at least
balance and cardiorespiratory functions were used as an outcome measure. We included
four studies, with, in total, 112 participants, aged between 51 and 93 years. The
intervention consisted of Taekwondo or Karate. Total training duration varied from 17 to
234 h. All four studies reported beneficial effects, such as improvement in balance, in
reaction tests, and in duration of single leg stance. We conclude that because of serious
methodological shortcomings in all four studies, currently there is suggestive, but
insufficient evidence, that hard martial arts practice improves physical fitness functions in
healthy people over 40. However, considering the importance of such effects, and the low
costs of the intervention, the potential of beneficial health effects of age-adapted, hard
martial arts training, in people over 40, warrants further study.
Keywords: hard martial arts; Tae Kwon Do; senior citizens
OPEN ACCESS
Societies 2014, 4 162
1. Introduction
The American College of Sport Medicine (ACSM) estimated that about 60% of Americans lack
sufficient daily exercise, while about 25% has almost none [1]. In the Netherlands, about 25% of
people lack sufficient daily physical activity, and about 10% do not exercise at all [2,3] A low level of
physical activity relates to an increased risk of cardiovascular disease, diabetes mellitus, osteoporosis,
and has a negative effect on mood, cognitive functions and overall wellbeing. With increasing age
these negative consequences lead to deterioration of mobility, jeopardizing self-maintenance and
increase the chance of dependency on others [4–6]. Especially dynamic locomotor components
deteriorate with age: steps become shorter, walking pace decreases, the time that both feet touch the
ground increases during walking straight, but also in curves and while turning [6,7]. A decreased
quality of the dynamic locomotor components also increases the risk of falling [8].
Exercise programs, including those based on martial arts, lower the chance of a number of negative
consequences of aging [9]. Physical activity and sports which are mainly focused on the training of
the proprioceptive system (balance sports like Tai Chi and Yoga) are effective in improving balance
and in reducing the prevalence of falls in the elderly [7]. Such sports are clearly better to improve
balance function than sports that aim to improve cardiovascular function (bioenergetic sports, such as
running) [10].
Martial arts are often considered as either “soft”, such as Tai Chi and Yoga, or “hard”, such as Tae
Kwon Do, Kung Fu, and Karate. Generally, hard martial arts focus on powerful execution of a limited
number of movement techniques (those which most quickly and successfully take the opponent out),
whereas soft martial arts primarily value the quality of execution of a much wider variety of movements;
without losing sight of the fact that these movements relate to defense and attack patterns [11].
However, some martial arts, such as Tae Kwon Do, contain both elements. The element which makes
hard martial techniques effective is the power to hit a target, which, apart from a certain degree of
technique, requires both muscle strength and speed of execution. As most movements in the hard
martial arts have a more dynamic nature than those in the soft martial arts, components of hard martial
arts training may be expected to be especially beneficial on dynamic locomotor components [12].
A number of studies and reviews examined the effects of soft martial arts, especially Tai Chi, on some
physical fitness components such as balance, but also on the risk of fall accidents in the elderly [6,13]
We hypothesize that hard martial art practice is more beneficial with regards to physical and mental
functions because it combines the elements of soft martial arts with those of bioenergetics sports.
Therefore, hard martial art practice could not only improve cardio-respiratory functions as in the
bio-energetic sports, but also balance maintenance as in the soft martial arts. As the hard martial arts
not only contain complex movement patterns as does, e.g., Tai Chi, they require a much more dynamic
performance of these complexes, by which the physical fitness component “motor coordination” may
especially benefit. A point of special interest, however, is balancing potential benefits against potential
injuries, the occurrence of which may depend on the complexity and intensity of movement practice.
A review of 23 studies on effects on some physical functions of taekwondo training suggested
benefits on aerobic capacity, body composition and flexibility. However, that review was descriptive
and considered no age specification [13]. In this paper we sought to study the evidence whether hard
martial art practice improves certain physical fitness components in people over 40. We set the age
Societies 2014, 4 163
limit at 40 for several reasons: above this age the sport practice has lost the aim of competitive gain,
whereas it is almost exclusively practiced for fun and physical and mental benefit, which were the
parameters for our review. As training practice intensity in this age group is generally lower than in
youngsters and young adults, not only a lower risk of training injuries may be expected, but any effect
on our parameters of interest may substantially vary between these age groups. Furthermore, there is a
psychological reason when 40 years of age may be regarded as being half-way one’s expected total life
span of 80. If shown to be effective, such practice could then be recommended as an effective, safe and
cost-effective method to improve certain health-related physical functions for people in this age category.
With this aim we performed a systematic literature review of hard martial art intervention studies.
2. Methods
2.1. Search Strategy
We conducted a broad computerized literature search, over a period without a fixed date of onset up
to May 2013, of Pubmed, Psychlit, Cochrane Database and Google search. Search terms were (a) hard
martial arts; (b) participants older than 40 years; (c) measurements: balance, cardiorespiratory
functions, mental functions (d) there was no time-limit and (e) written in English, Spanish, French,
German or Dutch. This was specified with the following key words: martial arts, hard martial arts, Tae
Kwon Do, Taekwondo, Karate, Hapkido, Kung Fu, older adults, aged, elderly and senior. We aimed
primarily at (randomized) controlled trials, but also included other type prospective intervention studies.
The titles and abstracts of identified published articles were reviewed in order to determine their
potential relevance tour aim. Also, reference lists of approved articles were screened for potentially
relevant articles, which were reviewed in the same manner. In order to make a final selection of the
studies for the review, one reviewer (GPD) applied all search criteria to the full text of the articles that
had passed the first screening for eligibility.
2.2. Risk of Bias Assessment
A dedicated quality of methodology checklist was drawn up, based on of the published Delphi list,
and with reference to the topic of the review [14]. The checklist was pretested using a non-randomized
controlled study that studied the effects of Tai Chi on balance and selected motor functions of the
elderly [15]. Only, minor changes had to be made for the final version (Table A1).
Two reviewers (GPD, PL) independently performed the methodological scoring of the selected
studies. Their scores were compared and discrepancies were resolved through discussion between the
reviewers. A third reviewer (JL) was to be consulted when differences could not easily be resolved.
2.3. Data Extraction
A study description form was developed based on standardized abstracting forms (Table A2). Data
on all reported outcomes were extracted and assessed.
Societies 2014, 4 164
2.4. Analysis
The methodological scoring list consisted of 18 items (see Table A1) with a positive, a partial and a
negative answer option, they were scored as 2, 1 or 0 points respectively. If bias was considered
unlikely, the item was scored positive. In case information was incomplete to allow good judgment,
the item was scored as “partial”, and without relevant information, “negative”. The article was
considered as poor with a score under 50%, reasonable with a score 50%–75%, and good above 75%.
Heterogeneity between studies did not allow statistical pooling of study results.
3. Results
3.1. Search Strategy
Our search resulted in 13 references of potential studies. Based on title and abstract, nine references
were selected and the full text review excluded three more, as the intervention in fact complied rather
with soft martial arts. One article was conducted by our own research group and was excluded because
of possible bias in assessing quality [16]. One study did not meet selection criteria, because it was a
retrospective trial [17].
Eventually, four papers were included in this review [9,18–20]. See Figure 1.
Figure 1. Results of search.
3.2. Risk of Bias Assessment
The four selected papers were two controlled trials, and two single arm intervention studies (Table 1).
The little disagreement between reviewers occurred because of reading errors and differences in
interpretation of the methodological criteria list. These differences could be easily resolved, and the
third reviewer was not called upon. The results of the methodological assessment are presented in Table 2.
Societies 2014, 4 165
Table 1. Characteristics of included studies.
Author
Year
Country
Design
Participants
Intervention
Reported Outcomes
Notes
Brudnak et al.
2001 [19]
Wisconsin, USA
SAI
IG: Community-dwelling volunteers
N = 12: ♂/♀ not mentioned
Mean age: not mentioned (range: 63–81)
RG: -
Drop-out: 50%, after first class
IG: Taekwondo
17 weeks
once per week, 1 h
total 1020 min
RG: -
Single leg stance: (s)
Sit-and-reach (cm)
Pushups (number in 30 s)
Participants
measured each
other in pairs
Cromwell et al.
2007 [9]
Texas, USA
CT
IG: Community-dwelling volunteers
N = 20: ♂: 3, ♀: 17
Mean age: 73 years (range: 60–83)
RG: Community-dwelling volunteers
N = 20: ♂: 7, ♀: 13
Mean age: 74 years (range: 59–88)
Drop-out: 0
IG: Taekwondo
11 weeks,
twice per week, 1 h
total 1320 min
RG: normal daily physical activity
Single leg stance (s)
Multidirectional reach test (cm)
Sit-and-reach (cm)
Timed up-and-go (s)
Cadence (steps/s)
Gait stability ratio (steps/s)
Walking velocity (m/s)
Chateau et al.
2010 [19]
Canada
SAI
IG: Working 50 years old volunteers
N = 15:♂ 15, ♀ 0
Median age: 57 years (range: 51–58)
RG: -
Drop-out: 7
IG: Karate
12 months
3 times per week. 1.5 h
total: 14040 min
RG: -
MOS 36 item Short Form Health Survey
Beck Depression Inventory
Reaction time (s)
Pronation and supination (s and Hz)
Finger tapping (s and Hz)
Sway path (mm)
Sway area (mm2)
Sway velocity (mm/s)
Effort by ergometric bycicle (units not mentioned)
Jansen et al.
2012 [20]
Germany
CT
IG: Community-dwelling volunteers N = 12:
♂ 4, ♀ 8 Mean age 74 years (range 69–81)
RG1: Community-dwelling volunteers N = 12:
♂ 5, ♀ 7 Mean age 83 years (range 72–93)
RG2: N = 12: ♂ 5, ♀ 7 Mean age 75 years
(range 67–82)
RG3: N = 9: ♂ 1, ♀ 7 8 Mean age 83 years
(range 70–89)
Drop-out: 15
IG: Karate-Do 3–6 months 20 training
sessions, 1 h total 1200 min
RG1: Physical exercise training 20
training sessions, 1h total 1200 min
RG2: Cognitive training 20 training
sessions, 1h total 1200 min
RG3: normal daily physical activity
Number-connection test (min)
Number-symbol test (number of correct symbols)
Digit-span test (number of span)
Figure test (units not mentioned)
Block-tapping test (number of blocks)
Depression scale (score)
CT = controlled trial; SAI = single arm intervention study; IG = index group; RG = reference group.
Societies 2014, 4 166
Table 2. Methodology assessment.
Brudnak et al. [18]
Cromwell et al. [9]
Chateau et al. [19]
Jansen et al. [20]
Rating
Points
Rating
Points
Rating
Points
Rating
Points
1
Randomization
No
(0)
No
(0)
No
(0)
No
(0)
2
Intention to treat analysis
No
(0)
No
(0)
Partly
(1)
Partly
(1)
3
Blinding assessors
No
(0)
Inadequate
(1)
No
(0)
No
(0)
4
Blinding participants
No
(0)
No
(0)
No
(0)
No
(0)
5
Blinding providers
No
(0)
No
(0)
No
(0)
No
(0)
6
Baseline characteristics
No RG
(0)
No
(0)
No RG
(0)
No, age difference
(0)
7
Care programs identical
No
(0)
No
(0)
No
(0)
Partly
(1)
8
Inclusion criteria
Inadequate
(1)
Inadequate
(1)
Clear
(2)
No
(0)
9
Exclusion criteria
Inadequate
(1)
No
(0)
Clear
(2)
No
(0)
10
Interventions
Not clear
(0)
Clear
(2)
Clear
(2)
Not clear
(0)
11
Outcome measures clear
Clear
(2)
Clear
(2)
Inadequate
(1)
Inadequate
(1)
12
Outcomes appropriately measured
Appropriate
(2)
No
(0)
Appropriate
(2)
Inadequate
(1)
13
Outcomes useful in daily activities
Adequate
(1)
Adequate
(1)
Adequate
(1)
Adequate
(1)
14
Surveillance and duration
Inadequate
(1)
Good
(2)
Good
(2)
Inadequate
(1)
15
Primary outcome defined
Inadequate
(1)
No
(0)
No
(0)
No
(0)
16
Compliance
Not clear
(0)
Inadequate
(1)
Inadequate
(1)
Clear
(2)
17
Adverse effects
Not described
(0)
Not described
(0)
Not described
(0)
Not described
(0)
18
Replicable
Partly
(1)
Partly
(1)
Yes
(2)
Partly
(1)
Quality Score
28% (10/36)
31% (11/36)
44% (16/36)
25% (9/36)
Societies 2014, 4 167
3.3. Study Characteristics
The study characteristics are presented in Table 1. Four studies with a total of 112 participants were
included in this review, which came from two studies on Tae Kwon Do, and two studies on Karate.
Brudnak et al. tested one group of community-dwelling volunteers who followed Tae Kwon Do
lessons for 1 h once a week, during 17 weeks. They functioned as their own reference group by
measuring before and after the intervention period. The outcome variables were change of trunk
flexibility, number of pushups and duration of single leg stance, and were measured before and
following the training period [18].
Cromwell et al. divided the study population of community-dwelling volunteers, an index and a
reference group, non-randomized. The division was based upon the choice of the volunteers. The index
group followed a Taekwondo 1 h lessons twice a week, for 11 weeks. The Tae Kwon Do classes
followed a standardized, clearly described curriculum. The non-exercising referents maintained their
current lifestyle.
The outcome measures consisted of single leg stance, multidirectional reach test, timed up-and-go,
walking velocity, cadence, gait stability ratio, sit-and-reach. They were measured before participation
and after 11 weeks of Taekwondo lessons [9].
Chateau-Degat et al. tested 15 healthy 50-year-old males, who attended adapted karate training,
which was clearly described, for at least three weekly sessions of 90 min each for 12 months. They
functioned as their own reference group and were measured at least one week before training,
6 months and 12 months after participation [19]. The outcome measures consisted of the MOS 36-item
Short Form Health Survey [21], the Beck Depression Inventory, reaction time, pronation and
supination, finger tapping, sway path, area and sway velocity, and effort [19].
Jansen et al. considered four groups of elderly people between 67 and 93 years of age: a physical
exercise group (N = 12), a cognitive training group (N = 12), one on Shokotan-Karate training (N = 12),
and a reference group (N = 9). This division mainly came about by the volunteers’ preference;
inhabitants of different nursing homes wanted to stay together, as did (married) couples. In each of the
4 groups 20 training sessions were provided in a period of 3–6 months. The outcome measures were:
cognitive speed, measured by the number-connection test and the number-symbol test; memory
performance, measured by the digit-span-test, the figure test and the block-tapping test; and the Centre
of Epidemiological Studies Depressions scale, which measures different stages of depressive
symptoms. They were measured prior to training, whereas post-testing was done immediately after the
last training session [20].
3.4. Methodological Characteristics
None of the studies had a randomized design. All the studies were performed after informed
consent was given. See Table 2 for further details. An important confounder for outcome measures is
compliance, which in Cromwell et al. it is not mentioned [9], whereas in Brudnak et al. there was a
drop-out rate of more than 50% after the first class [18]. Chateau-Degat et al. had a drop-out of 7
of 15 participants, whereas the attendance rate of the classes was not mentioned [19]. Jansen et al.
Societies 2014, 4 168
mentioned the drop-outs before study start. The reference group in that study had fewer training
sessions than the other groups [20].
Brudnak et al. measured one group of volunteers which functioned as their own reference group.
There was no blinding since there was only one group and participants measured each other. In- and
exclusion criteria were not well described; the authors did not explain why from the 27 recruited
participants only 12 could continue with the study. Furthermore they describe an initial drop-out rate
of 50%, but it remains unclear how many participants did complete the intended number of the Tae
Kwon Do classes. In effect on this indistinct description the mean age is uncertain, the participant’s
gender was not mentioned. The measurements conducted are described, and reproducible, however the
quality of the measurements is doubtful since the participants measured each other. The Taekwondo
classes are barely described, and it is unclear designed. Compliance and adverse effects were not
described. The methodological scoring list is added to the addendum 1 and summarized in Table 2, the
study scores an overall quality score of 10 out of 36 [18].
Cromwell et al. formed the groups based on patient preferences, the baseline characteristics were
not entirely similar, but did not differ much. A chi-square test was performed to confirm similarity of
health status between the Taekwondo and reference groups. The observers who measured the groups
were blinded, but clearly the participants were not. In- and exclusion criteria were not mentioned in
detail. No sample size calculation was performed prior to the study. The pre- and post-test
measurements were clearly described, could easily be repeated and were applicable in daily activities.
The intervention (Taekwondo) was clearly defined. Possible drop-outs were not mentioned. The
measures were analyzed using an ANOVA for repeated measures. Participation compliance was well
described and accounted for in analysis. Adverse effects were not reported. Therefore, the overall
quality score is low and is 11 out of 36 (Table 2) [9].
The study of Chateau-Degat et al. is a clinical trial which recruited 22 healthy 50-year-old male
volunteers, who attended adapted karate training, so there were no women enrolled. The training
content was well described and adapted to the participants’ ability. Blinding was not possible since
there was no reference group. It is unclear who conducted the measurements and whether these were
conducted by the same assessors at baseline, 6 months and 12 months. The in- and exclusions were
clearly described. There was a post hoc power sample size calculation; the power was 86.1%, and
considered adequate. The measurements were well described, but the outcome data were not described
completely and remain, therefore, partly unclear. Furthermore, not all the measurements, particularly
those at 6 months, were mentioned, but were only illustrated in a diagram. The drop-outs were well
described. The analysis was made by conventional t-test, with Fisher’s exact tests comparing
proportions or by the Mann-Whitney U-test. Compliance and adverse effects are not mentioned. There
is an intermediate overall quality score of 16out of 36 (Table 2) [19].
The study by Jansen et al. was a controlled intervention study. In total 45 older adults, ranging from
69 to 93 years of age, were enrolled. Inclusion and exclusion criteria were barely mentioned and not
clear. A post hoc Bonferroni correction showed that the participants of the physical exercise and
control group were significantly older than the participants in the other two groups. The intervention of
the several groups was not described clearly. In particular, the content and intensity Karate training
were vague. Although this was done “according to the German-Karate-Federation”, how these were
adapted to age was not described. Furthermore, outcome measurements were unclear and not rated
Societies 2014, 4 169
blindly. As analysis they performed a univariate analysis of variance, and although some of the
interactions were “statistically significant”, this does not allow concluding that the intervention was
causally related to the dependent variables. This all sums up to an overall quality score of 9 out of 36
(Table 2) [20].
3.5. Outcome Measurements
All the outcome measurements of the reviewed studies are listed in Table 3a–d.
3.6. Analysis
Our results show that all four included studies were of poor quality (score below 50%).
Table 3. Results.
(a). Results of Brudnak et al. [18].
Index
Group
Article
Measurement
Pre
Post
mean
mean
Brudnak
Sit-and-reach (cm)
Increase
>8.9
[18]
Pushups (number per 30 s)
Increase
1.8
Single leg stance (s): Right
Increase
>16
Left
Increase
16
Pre = Before training; Post = After training.
Societies 2014, 4 170
(b). Results of Cromwell et al. [9].
Index
Reference
Group
Group
Article
Measurement
Pre
Post
Sign.
Pre
Post
Sign.
Sign.
mean
sd
mean
sd
within groups
mean
sd
mean
sd
within groups
between groups
Cromwell
Single leg stance (s)
17.0
19.4
27.2
39.4
Ns
22.8
35.3
21.5
39.1
Ns
Ns
[9]
Multidirectional reach test (cm)
Front
23.4
7.8
27.0
8.5
Ns
23.8
3.3
23.1
7.0
Ns
Ns
Back
20.7
5.6
24.1
4.9
<0.05
21.5
4.8
21.8
6.4
Ns
Ns
Right
15.0
4.8
19.2
6.2
<0.05
14.8
4.3
14.9
4.6
Ns
Ns
Left
14.3
5.6
18.8
8.8
<0.05
13.7
4.8
15.3
5.1
Ns
Ns
Sit-and-reach (cm)
18.9
7.9
21.0
7.0
<0.05
20.9
8.3
19.8
8.1
Ns
Ns
Timed up-and-go (s)
9.5
1.7
8.6
2.1
<0.05
11.3
2.7
10.9
2.9
Ns
<0.05
Cadence (steps/s)
2.1
0.2
2.2
0.4
Ns
2.0
0.2
2.0
0.2
Ns
<0.05
Gait stability ratio (steps/m)
2.4
0.5
2.0
0.4
<0.05
2.4
0.7
2.4
0.5
Ns
Ns
Walking velocity (m/s)
0.9
0.2
1.1
0.3
<0.05
0.9
0.2
0.9
0.2
Ns
Ns
Pre = Before training; Post = After training; sd = Standard deviation; Sign = Significance (p < 0.05).
Societies 2014, 4 171
(c). Results of Chateau et al. [19].
Article
Measurement
Pre
6 months
12 months
Sign. pre vs.
Sign. pre vs.
sd
sd
sd
6 months
12 months
Chateau
Physical score
29.8
1.1
Nm
Nm
34.7
1.1
Nm
0.01
[19]
Mental score
50.9
1.3
Nm
Nm
50.2
1.3
Nm
0.67
Physical functioning (score)
81.9
1.9
Nm
Nm
88.0
1,9
Nm
0.02
Physical status (score)
Nm
Nm
Nm
Nm
Nm
Nm
Nm
Body pain (score)
69.9
2.2
Nm
Nm
84.5
2.4
Nm
0.04
General health (score)
13.9
0.7
Nm
Nm
16.4
0.7
Nm
0.01
Vitality (score)
61.0
1.6
Nm
Nm
69.12
1.6
Nm
<0.01
Social functioning (score)
Nm
Nm
Nm
Nm
Nm
Nm
Nm
0.77
Emotional status (score)
Nm
Nm
Nm
Nm
Nm
Nm
Nm
0.50
Mental health (score)
Nm
Nm
Nm
Nm
Nm
Nm
Nm
0.95
Reaction time (s) Right
0.23
0.01
0.23
0.01
0.23
0.01
0.71
0.86
Left
0.20
0.01
0.23
0.01
0.24
0.01
0.01
0.01
Pronation and supination
Precision (s) Right
0.01
0.02
−0.02
0.02
−0.26
0.02
0.04
0.11
Left
−0.03
0.02
−0.04
0.02
−0.36
0.02
0.41
0.66
Regularity Right
0.06
0.01
0.06
0.01
0.06
0.01
0.37
0.96
Left
0.05
0.01
0.05
0.01
0.05
0.01
0.15
0.82
Maximum (Hz) Right
5.43
0.32
6.07
0.30
6.10
0.32
<0.01
0.04
Left
5.07
0.24
5.85
0.23
5.88
0.26
<0.01
<0.01
Finger tapping
Precision (s) Right
−0.09
0.01
−0.06
0.01
−0.06
0.01
0.01
0.10
Left
−0.09
0.01
−0.06
0.01
−0.06
0.02
0.09
0.28
Regularity Right
0.09
0.01
0.06
0.01
0.06
0.01
0.03
0.08
Left
0.07
0.01
0.07
0.01
0.08
0.01
0.49
0.42
Maximum Right
6.72
0.27
6.35
0.27
6.23
0.30
0.27
0.24
Left
6.09
0.39
6.98
0.39
6.85
0.43
0.10
0.21
Mean sway Eyes (mm) open
5.6
0.5
6.0
0.5
6.1
0.5
0.36
0.36
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(c). Cont.
Article
Measurement
Pre
6 months
12 months
Sign. pre vs.
Sign. pre vs.
sd
sd
sd
6 months
12 months
Chateau
Closed
6.71
0.6
5.9
0.6
5.9
0.6
0.05
0.19
[19]
Transversal sway (mm) Open
3.0
0.2
3.1
0.2
3.1
0.2
0.46
0.57
Closed
3.9
0.4
3.4
0.3
3.3
0.4
0.10
0.17
Sagittal sway (mm) Open
4.1
0.5
4.4
0.5
4.6
0.5
0.43
0.40
Closed
4.6
0.5
4.1
0.4
4.2
0.5
0.12
0.40
Sway area (mm2) Open
316.6
40.0
315.2
38.6
321.3
0.8
0.96
0.80
Closed
507.9
87.5
404.9
84.1
399.2
89.3
0.09
0.22
Sway velocity (mm/s) Open
11.4
0.9
10.6
0.9
10.5
0.9
0.16
0.33
Closed
17.5
1.9
14.4
1.8
14.4
1.9
0.02
0.01
Sway intensity (mm) Open
4.4
0.3
4.4
0.3
4.4
0.3
0.97
0.93
Closed
6.2
0.5
5.4
0.5
5.4
0.5
0.01
0.04
Duration of effort (min)
10.9
0.5
Nm
Nm
12.2
0.6
Nm
0.04
Maximal power developed
198.0
10.0
214.8
10.2
0.01
0.01
Maximal heart rate (beats/min)
Nm
Nm
Nm
Nm
Nm
Nm
Nm
Nm
Individual effort profile
Nm
Nm
Nm
Nm
Nm
Nm
Nm
Nm
Beck depression score
9.8
1.1
4.9
1.0
4.9
1.1
0.01
<0.01
Pre = Before training; 6 months = After 6 months training; 12 months = After 12 months training; sd = Standard deviation Sign= Significance (P <0.05);
Nm = Not mentioned.
Societies 2014, 4 173
(d). Results of Jansen et al. [20].
Article
Measurement
RG
EG
CT
Karate
Effect of
Effect of
Interaction
Mean
SE
Mean
SE
Mean
SE
Mean
SE
group
time of testing
Jansen
Cognitive speed
[20]
Number-connection test (s)
45.51
3.8
29.72
3.45
23.83
3.28
29.31
3.41
6.31 *
0.01
0.125
Number-symbol test (items)
26.34
2.95
41.11
2.41
41.11
2.41
35.82
2.51
4.72 *
1.56
0.86
Memory performance
Nm
Nm
Nm
Nm
Nm
Nm
Nm
Nm
Digit-span test (number)
Nm
Nm
Nm
Nm
Nm
Nm
Nm
Nm
1.5
0.22
1.6
Figure test (score)
Nm
Nm
Nm
Nm
Nm
Nm
Nm
Nm
1.63
1.01
0.74
Block-tapping test (number)
Nm
Nm
Nm
Nm
Nm
Nm
Nm
Nm
1.03
1.03
0.85
Pre
Post
Pre
Post
Pre
Post
Pre
Post
Depression score
11
12.5
13.5
13
10
18
13
8
0.81
0.84
4.12
RG = Reference group; EG = Exercise group; CT = Cognitive training; sd = Standard deviation; SE = Standard error; Nm = Not mentioned; Pre =Before intervention;
Post = After intervention.
Societies 2014, 4 174
4. Discussion and Conclusions
Our aim was to do a systematic review of the available literature. Although our methods complied
with this aim, both quality and quantity of the material we analyzed did not allow us to explicitly fulfill
our original goal.
The number of reviewed studies was limited, as was their methodological quality, which illustrates
the lack of research in the area of health benefits of hard martial arts in people over 40. We found four
studies, which were all of a small size, whereas their intervention duration was rather short.
Furthermore, there were large differences in study design, outcome measures, methodological quality,
and character of training content. With only four studies found, one may consider a systemic review to
be a bit premature. However, our review may make investigators well aware of the idea that further
study is needed. The studies, nevertheless, suggest some benefit, and if proper studies could confirm
beneficial effects of hard martial arts training, such training could eventually be recommended as a
hopefully safe, pleasant and cheap way to maintain or even improve various physical fitness functions
in people over 40. Whether, or to what extent, benefits outweigh the risk of training injury cannot be
inferred from the four studies, as neither injury frequency nor injury severity was reported. This is
certainly an issue that should be included in any future studies. Preliminary data suggest that
when training programming is adjusted to account for age-related requirements, training injuries are
minor [22]. When looking at the proportion of ageing people in society who maintain a sedentary
lifestyle, substantial gain in health on a societal level might be attained if this age group could be
convinced to practice hard martial art forms. Such an approach could result in significant savings in
healthcare costs at a minimal amount of investment. An important potential benefit may be the
mitigation of age-related deterioration in mobility, which increases falls and jeopardizes
self-maintenance, both of which are rather costly affairs for society, especially when the proportion of
aged and very old people is on the increase [4,6,13].
Subjective benefits from martial arts training is often reported, especially in (generally Asian)
countries where the various arts originated. Without doubt we missed reports in the Asian languages,
and we cannot exclude such a language bias in our survey. Originally we aimed to include Kung Fu as
a hard martial art in our review, but the nine studies covered in a 2008 systematic review of health
benefits of this art were all on younger age groups, whereas we were unable to find any later published
study on an age group above 40 [23].
We excluded one study because it was a retrospective study and thus not an experimental design:
Douris et al. investigated a group of martial arts practitioners and a reference group consisting of
sedentary community members. The martial arts practitioners had participated in Soo Bahk Do training
during three years or more, a minimum of twice a week for 1 h a day. All classes were led by a
certified Soo Bahk Do instructor. The reference group did not engage in physical exercise other than
normal daily activities. Single leg stance was significantly longer with 35 s more, the sit-and-reach test
showed a difference of 11.8 cm in favor of the Soo Bahk Do group, with a p-value of 0.01 [17].
The Karate and Taekwondo studies incorporate straight line powerful blocking, kicking and
punching techniques as a major exercise component. However, generally the rates of kicking
techniques, often combined with turning and jumping movements, amount to about 75% of exercises
in Taekwondo, but only 25% in Karate. Therefore, although these various styles are all listed as “hard”
Societies 2014, 4 175
martial art, they differ quite substantially in technical content, and their effects on separate physical
fitness components may also vary. Especially the practice of more dynamic movement patterns, such
as practiced in Taekwondo, may stimulate balance function. The four studies listed in this paper also
showed differences in training effects, but the numbers were too small for a reliable comparison.
From this review we may conclude that current evidence that hard martial arts practice improves
physical fitness functions in healthy people over 40 is suggestive, but not convincing. Our analysis
together with the consideration of the potential health and health cost benefit, leads us also to conclude
that the subject warrants further study. New studies should be properly designed, report training
programming, dose, and assessment, and also report on adverse events, whereas criteria for outcome
assessment should clearly be described. Studies should have a set duration of the training intervention
of probably at least one year, whereas they may focus not only on physical but also on cognitive
aspects. Moreover, aspects such as safety, program feasibility, and long-term adherence should also be
addressed. More reliable data are required before age-adapted hard martial art training in people over
40 can be recommended as a means to mitigate the age-related decline of various physical functions.
Author Contributions
G. Pons van Dijk conducted the search for the reviewed articles and together with P. Leffers they
determined all the criteria and selected the articles. G. Pons van Dijk and P. Leffers both reviewed the
articles. In case of any differences J. Lodder was consulted. G. Pons van Dijk wrote the paper and P.
Leffers and J. Lodder suggested corrections.
Appendixes
Table A1. Quality rating (internal validity).
Item
Points
Rating
1. Was the assigned intervention adequately
concealed prior to allocation?
2
Method did not allow disclosure of assignment
1
Small but possible chance of disclosure of assignment or unclear
0
Quasi-randomized or open list/tables
2. Were the outcomes of participants who
dropped out described and included in the
analysis (intention to treat)?
2
Drop outs well described and accounted for in analysis
1
Drop outs described and analysis is not possible
0
No mention, inadequate mention or obvious differences and no adjustment
3. Were the outcome assessors blinded to
intervention status?
2
Effective action taken to blind assessors
1
Small or moderate chance of unblinding of assessors
0
Not mentioned or not possible
4. Were the participants blind to assignment
status after allocation?
2
Effective action taken to blind participants
1
Small or moderate chance of unblinding of participants
0
Not possible or not mentioned, or possible but not done
5. Were the intervention providers blind to
assignment status?
2
Effective action taken to blind intervention providers
1
Small or moderate chance of unblinding of intervention providers
0
Not possible or not mentioned, or possible but not done
6. Were the intervention and control group
comparable at entry?
2
Good comparability of groups, or confounding adequately adjusted for in analysis
1
Confounding small; mentioned but not adjusted for
0
Large potential for confounding, or not discussed
7. Were care programs, other than the
intervention identical (co-intervention)?
2
Care programs clearly identical
1
Clear but trivial differences
0
Not mentioned or clear and important differences in care programs
Societies 2014, 4 176
Table A1. Cont.
Item
Points
Rating
8. Were the inclusion criteria clearly
defined, appropriate selection of study
participants, for the purpose of the study?
2
Clearly defined
1
Inadequately defined
0
Not defined
9. Were the exclusion criteria clearly
defined, appropriate selection of study
participants, for the purpose of the study?
2
Clearly defined
1
Inadequately defined
0
Not defined
10. Were the interventions clearly defined
and appropriately applied?
2
Clearly defined interventions are applied with a standardized protocol
1
Clearly defined interventions are applied but the application protocol is not standardized
0
Intervention and/or application protocol are poorly or not defined
11. Were the outcome measures used clearly
defined?
2
Clearly defined
1
Inadequately defined
0
Not defined
12. Were the outcome measures used
appropriately measured?
2
Appropriately measured
1
Inadequately measured
0
Not defined
13. Were test used in outcome assessment
useful in daily activities?
2
Optimal
1
Adequate
0
Not defined, not adequate
14. Was the surveillance active and of
appropriate duration?
2
Active surveillance and appropriate duration
1
Active surveillance, but inadequate duration
0
Surveillance not active or not defined
15. Were point estimates and measures of
variability presented for the primary
outcome measures?
2
Yes
1
Point estimates, but no measures of variability presented
0
Vague descriptions
16. Was the compliance rate in each group
likely to cause bias?
2
Compliance well described and accounted for in analysis
1
Compliance well described but differences between groups not accounted for in analysis
0
Compliance unclear
17. Was there a description of adverse effects
of the intervention?
2
Well described
1
Poorly described
0
Not described
18. Is the intervention replicable and
feasible?
2
Yes
1
Partly
0
No
Table A2. Study description/characteristics inventory.
Category
Design
Type of study design
RCT, Controlled Trial, uncontrolled Trial, cohort; cross-section
Method of group allocation
Random number table; computer random number generator; coin toss
Blinding of group allocation
Therapist and/or patient; sealed envelopes
Duration of follow-up period
Power sample size calculation
sample size needed for adequate statistical power
Subject selection
Setting
Country
Year of study
Inclusion and exclusion criteria
Societies 2014, 4 177
Table A2. Cont.
Planned interventions
Description of experimental intervention
Type of martial arts; description of content of training sessions
Description of reference intervention
Time per intervention session
Frequency intervention sessions
Duration of intervention period
Total number of interventions
Cumulative training time in study
Outcome definition
All collected outcomes variables
Units of measurement, upper and lower limits of ordinal scales
Measurements
Time points of collected data
Adverse effects
Subjects per group
Number of subjects
Ethnicity
Proportions
Age
Mean and SD; median; range
Gender
Proportions
Socio-demographic characteristics
Co-morbidity
Reported results per group
Outcome measures
Proportions; means and SD; medians; ranges
Intention to treat analysis
Cumulative training time
Loss to follow-up
Summary of all outcome measurements
Adverse events
Data analysis
Type of analysis
Intention to treat; per protocol analysis
Estimates of effect measures
RR, (OR), AR, NNT, difference of means; CI’s and/or p-values
Subgroup analysis
Differences of effect measures between subgroups
Drop outs
Drop out, lost to follow-up, missing data, crossover
Limitations
Internal validity
Research question free from bias, methodology
Confounding
Differences in baseline characteristics
Concerns about external validity
Appropriate research question, generalizability/applicability of findings
Main conclusions according to authors
Miscellaneous
Source of funding
Year of publication
Miscellaneous comments from authors
RCT = Randomized controlled trial; SD = Standard deviation; RR = Relative risk; OR = Odds ratio;
NNT = Number needed to treat; CI= Confidence interval.
Conflicts of Interest
The authors declare no conflict of interest. This article does not contain any studies with human or
animal subjects performed by any of the authors.
Societies 2014, 4 178
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