Original articles

Comparison of brain nervous system activity and psychological changes before and after
net-step exercise in Japanese adults of advanced age
Yoshie Nagata*, Mikuri Kaga**, Satoko Showa*, Asae Oura*,
Hirofumi Ohnishi*, Mitsuru Mori***
Abstract Objective: Exercise for people’s health are important in aging society. The net-step exercise, which was developed in
Hokkaido and spread all over Japan at the present time. This study was performed to investigate the physiological and psychologicalchanges induced by net-step exercise in Japanese adults of advanced age.
Methods: We visited two net-step exercise classes and recruited 22 older adults. Brain waves and Two-Dimensional Mood Scale(TDMS) scores were measured before and after the net-step exercise in 22 adults of advanced age (mean age=75.5 years, SD=5.4 years)of both sexes.
Results: The distribution rate of alpha-2 waves was significantly higher after than before exercise (P=0.03). Brain waves except alpha-2
waves was no significant changes. Similarly, the vitality, stability, and pleasure scores in the TDMS were significantly higher after than
before exercise (P=0.01). However, arousal level scores was not showed significant difference.
Conclusion: These results suggest that the participants felt relaxation, concentration, and a high-spirited feeling by engaging in thisexercise.
Keywords :Net-step exercise, Brain nervous system activity, Psychological changes, Japanese older adults

Introduction

training5). A dual-task exercise, which is called a net-step

According to the 2018 Population Census of Japan, theexercise, was developed as a health activity inpercentage of people aged >65 years is 27.7% of the total

community-dwelling adults of advanced age in Hokkaido,

population. The percentage continues to rise and isJapan in 20056). This exercise is considered to provide an

expected to reach an estimated 38.4% by 2065. Thus, theopportunity for social participation in older adults7). Net-

extension of a healthy life expectancy is important tostep exercise, in the capacity of dual-task training, might

ensure that older adults can live independently in ahave a positive effect on physical and mental health. A

familiar community.

few studies have shown the relationship among cognitive

Physical activity, which is one method for extension offunction, depressive symptoms, and net-step exercise8,9).

a healthy life expectancy in older people, is expected to

However, no reports have identified an association

reduce the decline in cognitive function1) and the risk ofbetween brain nervous activity as a physiologicaldementia2). Physical activity is also a preventative factor

parameter and net-step exercise.

against coronary heart disease3) and depression4). Dual-In the present study, we investigated the influence oftask training reportedly improved motor functions in

net-step exercise on physiological and psychologicalolder individuals who participated in cognitive dual-taskchanges in Japanese adults of advanced age.

2020 年 2 月 25 日受付，2021 年 2 月 22 日受理* Department of Public Health, Sapporo Medical
University School of Medicine, Sapporo, Japan* * Department of Orthopaedic Surgery, Sapporo
Medical University Hospital, Sapporo, Japan** * Department of Rehabilitation, Hokkaido Chitose
College of Rehabilitation, Chitose, Japan

Materials and Methods
Participants
Recruitment was conducted through announcements from
August to September 2015 in two net-step exercise houses in
Sapporo, Japan. The study included 22 older adults (aged 71–81
years) of both sexes. The exclusion criterion was the presence of a
cardiac pacemaker.

-9-Comparison of brain nervous system activity and psychological changes before and after net-step exercise in Japanese adults of advancedage

All participants received written information on the trial andprovided signed informed consent.

were calculated using the four above-mentioned categories10) :vitality level score = (1) − (2), stability level score = (3) − (4),pleasure level score = [(1) + (3)] – [(4) − (2)], and arousal level

Methods

score = [(1) + (4)] – [(3) − (2)]. Higher scores indicated a more

Net-step exercise involves the use of nets with a length of 4 m,

positive psychological state.

width of 1.5 m, and squares of 50 × 50 cm that form a grid of 24
squares (3 × 8)6). The participants slowly step over the net without

Statistical analysis

setting their foot on the net using many different stepping patterns.

The Wilcoxon signed-rank test was performed to assess the

The duration of the net-step exercise in the present study was about

before and after exercise differences in the distribution rate of each

1 hour, including a warm-up activity of 15 minutes. First, thebrain wave and the four scale scores of the TDMS. The level ofparticipants watched the instructor’s demonstration step. Twostatistical significance was set at a P of <0.05. The analyses wereparticipants then formed a pair and took the same step while

performed with a commercially available statistical software

singing a nursery rhyme. The other participants watched withpackage (Dr. SPSS II for Windows; SPSS Japan Inc., Tokyo,

pleasure until their own turn.

Japan).

The initial data obtained from the participants were sex, age,commencement time of net-step exercise, and frequency per week

Ethical considerationsof net-step exercise. We subsequently measured the participants’physiological and psychological parameters before and after theThis study was approved by the ethics committee of the
Hokkaido Chitose College of Rehabilitation University.

net-step exercise.
With respect to physiological parameters, the participants

Results

underwent electroencephalography for 1 minute for examination

The mean age of the 22 participants (21 women, 1 man) wasof brain nervous activity after resting for 1 minute immediately

75.5 years (range, 71–81 years). The mean participation period of

following the net-step exercise. For electroencephalography

the net-step exercise was 8.2 months (range, 2.0–14.4 months), andmeasurement, participants rested on a chair with their eyes closed.

82% of the participants engaged in the exercise one or two times

Electroencephalography was performed using Brain Pro-Lightper week.

FM-828 (Futek Electronics Co., Ltd., Yokohama, Kanagawa,

Changes in the distribution rate of the five brain waves before

Japan), which is a simplified and handheld high-power device. A

and after net-step exercise are shown in Table 1. The median

sensor band was attached to the participant’s forehead. The

distribution rate of the alpha-2 waves significantly increased from

exploratory electrode was Fp2 according to the international 10/20

11.7% before exercise to 12.5% after exercise (P=0.03). In contrast,

system. The sampling frequency was 1,024 Hz, and the filters usedthe distribution rate of the other four brain waves (theta waves,

were 5 Hz, 8 Hz, 10 Hz, 12 Hz, and 20 Hz. Electroencephalograms

alpha-1 waves, alpha-3 waves, and beta waves) showed nowere Fast Fourier Transform (FFT) -converted data. Frequency

significant change.

bands were divided into theta waves (4–7 Hz; sleep state), alpha-1

Table 2 shows the changes in the TDMS scores before and after

waves (8–9 Hz; relaxed state), alpha-2 waves (10–11 Hz; relaxed

net-step exercise. Significant increases were noted in the medianconcentration state), alpha-3 waves (12–13 Hz; tense concentration

vitality level scores (before and after exercise scores, 4.0 and 6.5;

state), and beta waves (14–30 Hz; anxiety and strain state). The

P=0.02), stability level scores (before and after exercise scores, 4.5

distribution rate of each wave was calculated and used for analysis.

and 8.0; P =0.03), and pleasure level scores (before and after

Psychological parameters were measured using the Two-

exercise scores, 8.0 and 14.0; P=0.01), suggesting a positive

10)

Dimensional Mood Scale (TDMS) . The TDMS is composed of

psychological effect of net-step exercise. However, the arousal

eight questionnaire items, and the mood assessment scale consists

level scores were not significantly different before and afterof the vitality level, stability level, pleasure level, and arousal level.

exercise.

The eight questionnaire items represent the four quadrants of a twodimensional coordinate plane. The four categories are (1) higharousal-pleasure, (2) low arousal-displeasure, (3) low arousalpleasure, and (4) high arousal-displeasure. The TDMS score isdetermined using a 6-point Likert scale. Four mood scale scores- 10 -

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日本認知症予防学会誌
Vol.10 No.2, 2020

Table 1 Changes in distribution rate of brain waves on before and after

supports the effects of all three of the above-mentioned

the net-step exercise

characteristic features of the net-step exercise and indicates that theparticipants felt more relaxed and that tension was relieved after theMedian level (%) [25-75 percentile]
Brain waves

Beta

Before net-stepAfter net-step

exercise

exercise28.2 [ 20.5-35.6 ]25.6 [ 20.8-35.6 ]P*

net-step exercise.
No studies have measured brain waves as an effect of the netstep exercise. Research has shown that alpha waves are

0.99

significantly elevated by yoga. One study showed that alpha waves
were significantly affected by yoga in 18- to 37-years-old

Alpha-3

19.0 [ 17.0-25.1 ]17.4 [ 15.4-23.1 ]0.08

Alpha-2

11.7 [ 6.8-17.8 ]12.5 [ 8.9-19.0 ]0.03

Alpha-1

15.3 [ 9.5-23.3 ]14.6 [ 11.1-21.4 ]0.69

university students. The students continued performing yoga threetimes a day for 21 days. The alpha waves were 57.85% higher after
than before yoga11). Another study showed that alpha brain waves
were significantly higher (about 1.2 times) after than before yoga
exercise in women with premenstrual syndrome12). Each yogaTheta21.2 [ 15.6-30.4 ]18.8 [ 13.1-28.8 ]0.45

session was 50 minutes long and consisted of 5 minutes ofbreathing exercises, 35 minutes of yoga pose practice, and 10*Wilcoxon rank sum test

minutes of relaxation. These studies suggest that the elevation ofalpha brain waves is a relaxation effect provided by yoga. In

Table 2 Changes in Two-Dimensional Mood Scale (TDMS) scorescontrast, the rate of increase in alpha waves was about 1.1 times

on before and after the net-step exercise

smaller with the net-step exercise than with yoga. We consider that

TDMS

this difference was caused by the combined relaxation andMedian levels (scores) [25-75 percentile]P*

Before net-stepAfter net-step

exercise

exercise

Vitality

4.0 [ 1.5-6.0 ]6.5 [ 2.5-8.0 ]0.02

Stability

4.5 [ 3.0-7.3 ]8.0 [ 5.0-9.3 ]0.03

Pleasure

8.0 [ 7.0-12.0 ]14.0 [ 10.5-16.3 ]0.01

Arousal-1.0 [ -4.0-2.0 ]-1.0 [ -5.0-1.3 ]0.93levelsconcentration effects of the measured alpha-2 waves in our study.
Although alpha-1 and alpha-3 waves decreased after the net-step
exercise, the decrease was not significant. Alpha-1 waves reflectrelaxation with low-grade awakening owing to approaching theta
waves, and alpha-3 waves induce a lower stress state owing toapproaching beta waves. Participants obtained relaxation withhigh-grade awakening according to a significant elevation in alpha2 waves after the net-step exercise. Therefore, this could have led
to the reduction in the alpha-1 and alpha-3 waves being
insignificant.

*Wilcoxon rank sum test

The present study showed significant increases in the vitality,
stability, and pleasure level scores after net-step exercise. The

Discussion
The net-step exercise has three characteristic features6). (1) This
exercise requires two people to walk carefully and rhythmically.
The participants waiting for their turn remain seated in chairsaround the net. (2) The participants must remember the step patternbased on the instructor’s demonstration. (3) The instructor andwaiting participants watch and encourage the participants and do
not mention any mistakes that were made during the net-step
exercise. This suggests that the participants must concentrateduring the net-step exercise and that they are relaxed because of thefriendly atmosphere.
In this study, the distribution rate of alpha-2 waves was
significantly higher after than before the net-step exercise. This

characteristics of the net-step exercise suggest that the participants’concentration increases and that they are relaxed because of thefriendly atmosphere. In a previous study, physical activity such as
walking, jogging, and net-step exercise were associated withdecreased depression8,13,14). Increases in the vitality, stability, andpleasure level scores lead to improvements in depressive
symptoms and higher vitality, stability, and pleasure. The featuresof the net-step exercise suggest that the participants gain improved
concentration, relaxation, and a heightened mood by exercise. Thisin turn suggests that they will feel fresh and more relaxed after netstep exercise as a psychological effect.
The high vitality level score indicates an energetic and lively
status. An increased stability level score, indicates relaxation andcalmness, and an increased pleasure level score indicates comfort- 11 -

Comparison of brain nervous system activity and psychological changes before and after net-step exercise in Japanese adults of advancedage3) Noda H, Iso H, Toyoshima H, et al. (2005) Walking andsports participation and mortality from coronary heartdisease and stroke.J Am Coll Cardiol. 46: 1761-1767.
4) Smith TL, Masaki KH, Fong K, et al. (2010) Effect ofwalking distance on 8- year incident depressive symptoms
in elderly menwith and without chronic disease: the
Honolulu-Asia Aging Study.J Am Geriatr Soc. 58: 14471452.
5) Li KZ, Roudaia E, Lussier M, et al. (2010) Benefits ofcognitive dual-task training on balance performance inhealthy older adults. J Gerontol A Biol Sci Med Sci. 65:
1344-1352.
6) Kitazawa K, Showa S, Hiraoka A, et al. (2015) Effect ofadual-task net-step exercise on cognitive and gait function
in older a dults. J Geriatr Phys Ther. 38: 133-140.
7) Jindo T, Tsunoda K, Kitano N, et al. (2016) Pedometers
affect changes in lower-extremity physical function
during a square-stepping exercise program in older
Japanese adults. J Geriatr Phys Ther. 39:83-88.
8) Showa S, Kitazawa K, Takeuchi M, et al. (2015) Net-step
exercise And depressive symptoms among thecommunity-dwelling elderly in Japan. The Sapporo Med.
J. 84: 19-26.
9) Showa S, Kitazawa K, Takeuchi M, et al. (2016) Influenceof volunteer-led net step exercise class on older people’s
self-rated health in a depopulated town: A longitudinal
study. SSM –Population Health. 2: 136-140.
10) Sakairi Y, Nakatsuka K, Shimizu T. (2013)
Development of the two-dimensional mood scale forself-monitoring and self-regulation of momentarymood states. Japanese Psychological Research. 55: 338349.
11) Ganpat TS, Nagendra HR, Selvi V. (2013) Efficacy of
yoga for mental performance in university students.
Indian J Psychiatry. 55: 349-352.
12) Wu WL, Lin TY, Chu IH, et al. (2015) The acute effectsof yoga on cognitive measures for women withpremenstrual syndrome. J Altern Complement Med. 12:
364-369.
13) Heesch KC, Burton NW, Brown WJ. (2011) Concurrent
and prospective associations between physical activity,
walking and mental health in older women. J Epidemiol
Community Health. 65: 807-813.
14) Julien D, Gauvin L, Richard LJ, et al. (2011) The role ofsocial participation and walking in depression amongand feeling energetic10). There are no studies on the effects of netstep exercise and brain waves on TDMS scores. However, it is
known that increasing alpha brain waves enhances relaxation,
concentration, and provides calming effect. Therefore, we
speculate that the rise in vitality, stability, and pleasure level scoresis associated with the status of increasing alpha brain waves.
This study has several limitations. First, our sample size wassmall, which resulted in a reduced statistical power. Second, theparticipants of this study were restricted to urban areas; thus, theresults may not represent other adults of advanced age. Third, someof the question items in the TDMS are probably difficult for older
adults to understand. Therefore, it is possible that the participants
could not accurately answer the questions. Finally, this was a crosssectional study, and the assessments were only performed before
and after participation in the net-step exercise. In addition, we did
not consider detailed data such as the amount of exercise performed
or the time spent watching the other participants. Further research
will be required to compare a net-step exercise group and a control
group for an accurate assessment.
In conclusion, this study showed that the net-step exercise
inducesbothphysiologicalandpsychologicalchangescharacterized by a significantly increased alpha-2 brain waves
distribution rate and higher vitality, stability, and pleasure level
scores. Our results suggest that the physiological and psychologicaleffects of the net-step exercise might increase relaxation andconcentration for Japanese adults of advanced age.

Acknowledgments
The authors would like to thank all the participants in this study,
and net-step exercise houses workers. We would like to thank
Editage (www.editage.com) for English language editing.

Self-Declaration of Conflicts of Interest
The authors have no conflicts of interest to declare.

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一般社団法人

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日本認知症予防学会誌
Vol.10 No.2, 2020