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Effects of Body-weight Squat Training on Muscular Size, Strength and Balance Ability in Physically Frail Older Adults


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The purpose of this study was to evaluate the effects of a 12-week group-based body-weight squat training program on muscle mass, muscle strength, and balance in physically frail community-dwelling older men and women. Fifteen older adults (mean age = 78.7 yr) who needed assistance performing activities of daily living (ADL) according to long-term care insurance regulations in Japan participated in the study. Participants performed squat exercise in a group-setting using body-weight as resistance while singing for one set consisting of 48 reps twice weekly for 12 weeks. Body mass, thigh girth, thigh muscle thickness assessed by B-mode ultrasound, knee extension torque (KET), static and dynamic balance (static (SB): sway velocity (SV) standing on firm or foam surfaces with eyes open or closed; dynamic (DB): limits of stability) were measured before and after the intervention. Following the intervention, participants significantly (P< 0.05) decreased body mass and increased KET relative to body mass. Although thigh girth did not change, thigh muscle thickness did increase. There were no appreciable changes in DB nor in SB, except SV standing on a firm surface with the eyes open improved. Group-based body-weight squat exercise in physically frail older adults improves muscle mass and strength but has little effect on balance parameters.
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International Journal of Sport and Health Science Vol.14, 21-30, 2016
Int. J. Sport Health Sci.
Paper : Physiology
EŠects of Body-weight Squat Training on Muscular
Size, Strength and Balance Ability in Physically Frail
Older Adults
Eiji Fujita
, Nobuo Takeshima
, Yoshiji Kato
, Makoto Narita
Hiroki Nakamoto
and Michael E. Rogers
Department of Sport and Life Science, National Institute of Fitness and Sports in Kanoya
1 Shiromizu, Kanoya, Kagoshima 891-2393 JAPAN
E-mail: takeshima
Active Aging Association
2-92 Namiuchi-cho, Kita-ku, Nagoya, Aichi 462-0041 JAPAN
Department of Sports Humanities and Applied Social Science, National Institute of Fitness and Sports in Kanoya
1 Shiromizu, Kanoya, Kagoshima 891-2393 JAPAN
Department of Human Performance Studies, Center for Physical Activity and Aging, Wichita State University
106G Heskett Center, 1845 Fairmount St., Wichita, Kansas 67260-0016 USA
[Received January 13, 2015; Accepted March 4, 2016; Published online May 31, 2016]
The purpose of this study was to evaluate the eŠects of a 12-week group-based body-weight
squat training program on muscle mass, muscle strength, and balance in physically frail com-
munity-dwelling older men and women. Fifteen older adults (mean age
78.7 yr) who needed
assistance performing activities of daily living (ADL) according to long-term care insurance
regulations in Japan participated in the study. Participants performed squat exercise in a group-
setting using body-weight as resistance while singing for one set consisting of 48 reps twice
weekly for 12 weeks. Body mass, thigh girth, thigh muscle thickness assessed by B-mode
ultrasound, knee extension torque (KET), static and dynamic balance (static (SB): sway velocity
(SV) standing on ˆrm or foam surfaces with eyes open or closed; dynamic (DB): limits of stabil-
ity) were measured before and after the intervention. Following the intervention, participants
signiˆcantly (
0.05) decreased body mass and increased KET relative to body mass. Although
thigh girth did not change, thigh muscle thickness did increase. There were no appreciable
changes in DB nor in SB, except SV standing on a ˆrm surface with the eyes open improved.
Group-based body-weight squat exercise in physically frail older adults improves muscle mass
and strength but has little eŠect on balance parameters.
Keywords: Body-weight squat training, speciˆcity of exercise, frail older adults
1. Introduction
With a rapidly growing older population, loss of
independence has become a serious problem in
Japan as well as around the world. This has led to a
growing number of adults requiring long-term care
that imposes medical expenses and social burdens.
One quality for successful aging is the ability to
independently perform activities of daily living
(ADL) such as standing from a seated position,
walking, and climbing stairs (Hazell, et al., 2007).
Because muscle weakness and poor balance are asso-
ciated with an increased risk of disability (Guralnik
et al., 1995) and falls (Tinetti et al., 1986), many ex-
ercise programs have been developed to improve
these capacities in older adults (Chang et al., 2004;
2004). Additionally, several studies have shown that
resistance exercise, particularly machine-based
exercise and/or using dumbbells or free weights, is
beneˆcial for frail older adults as well as healthy
older adults (Fiatarone, et al., 1994; Mihalko and
McAuley, 1996). However, it is typically not feasible
to have large, expensive training equipment in day
service centers that provide care for older adults.
Previous research has shown that training with
Int. J. Sport Health Sci.
ankle-weight cuŠs and resistance bands, or using
participants' body weight as resistance, to be eŠec-
tive but no details were provided regarding the exer-
cise intensity used in these interventions (Yamauchi
et al., 2005; Rosie and Taylor, 2007; Shaw and
Snow, 1998; Takeshima et al., 2013; Yoshitake et
al., 2011).
Recently, we reported that the activity level of the
quadriceps femoris during a body mass-based squat
movement is in‰uenced by its force generation
capability (Fujita et al., 2011). For individuals with
a knee extension torque (KET) relative to body
mass less than 1.9 Nm/kg
, body mass-based squat
movement is considered to be a fairly high-intensity
activity. The breakpoint of 1.9 Nm/kg
may be
assumed to be a threshold level of knee extensor
strength, which should be maintained to perform
ADL without great di‹culty. Although, body mass-
based squat movement seems of adequate exercise
intensity for frail older adults, little is known about
the eŠects of long-term training using this activity.
Age-related loss in knee extensor strength in-
creases the di‹culty of performing ADL, such as
walking, rising, and stepping (Hortob áagyi et al.,
2003) and the risks of falling and associated fracture
(Wolfson et al., 1995; Kirkendall and Garrett,
1998). Moreover, a sit-to-stand movement like
squatting requires greater muscle strength than other
daily activities, such as walking or stair climbing
(Ploutz-Snyder et al., 2002; Yoshioka et al., 2007).
Therefore, the development of an eŠective interven-
tion that targets the knee extensors would be of
beneˆt to frail older adults.
Despite the known beneˆts of exercise in main-
taining independence, participation rates are not
high among all age groups (Ashworth et al., 2005).
Previous studies have used home-based exercise pro-
grams that can be less costly and do not require par-
ticipant transportation but program adherence and
appropriate exercise progression can be problematic
(Olson et al., 2011). Older adults value the sense of
fulˆllment provided by the social interactions with
the other participants, as well as the support and
encouragement received from the group (Dionigi,
2007; Layne et al., 2008). In addition, the social sup-
port given in group-based programs can counteract
the isolation that older adults often experience, and
companionship during activities improves physical
activity among older adults (Layne et al., 2008;
Shores et al., 2009). Furthermore, those who re-
ported high enjoyment in physical activity were
more likely to report higher levels of activity
(Salmon et al., 2003).
The purpose of this study was to evaluate changes
in muscle strength, muscle mass, and balance in
physically frail community-dwelling older men and
women following a 12-week group-based exercise
program consisting of squat exercise using partici-
pants' body weight as resistance while singing
2. Methods
2.1. Participants and exercise program
Fifteen older adults (6 males and 9 females) who
needed assistance performing ADL according to
long-term care insurance regulations in Japan par-
ticipated in the study. The means and standard devi-
ations (SDs) of age, height, and body mass for the
participants were 78.7
4.1 years, 151.5
8.7 cm,
11.4 kg, respectively. Height was measured
using a digital stadiometer (DSN-90, Muratec-KDS,
Kyoto, Japan) to the nearest 0.1 cm. Body weight
scale (HBF-214, Omron, Tokyo, Japan). Table 1
shows nursing care levels and presence of diseases at
The ethical committee of the National Institute of
Fitness and Sports in Kanoya approved the study.
All participants received written and oral instruc-
tions for the study and each gave their written in-
formed consent prior to participation.
All participants performed the squat exercise us-
ing body-weight as resistance for one set of 48 reps
while singing together on 2 days per week for 12
weeks. Starting in the seated position, participants
completed 48 reps by continuously standing from
and sitting in a standard chair (seat height 43 cm)
(Figure 1). Each full repetition took approximately
4 sec with the entire set being completed in approxi-
mately 3.5 min. Based on the work of Fukunaga
(2006), participants sang traditional songs while per-
forming the exercise. The goal of this was to prevent
the Valsalva maneuver and to create an atmosphere
of happiness.
2.2. Testing
Measurements included body mass, thigh girth,
Table 1 Characteristics of Participants
Participants Sex Nursing
care level pressure of disease
A m S1 asthma, osteoporosis
B m S2 lumbar canal stenosis
C m L1 parkinson disease
D m S1 hypothyroidism, lumbar spondylosis
E m L2 brain infaction (right hemiplegia), angina pectoris, cervical spondylotic myelopathy
F m L1 diabetes, hypertension, kidney disease (requiring dialysis)
G f S2 diabetes, angina pectoris, ossiˆcation of the posterior longitudinal ligament
H f L1 lumbar spondylolisthesis
I f S2 parkinson disease, diabetes, osteoporosis
J f S2 femoral neck fracture (femoral head replacement), diabetes, hypertension
K f S1 parkinson disease
L f L1 brain infaction (left hemiplegia), lung cancer
M f S1 lumbar spondylosis, knee osteoarthritis
N f S1 diabetes (retinopathy and peripheral neuropathy), cerebral infarction sequelae
O f S2 diabetes, hypertension, epilepsy, thoracic compression fracture, cerebral infarction sequelae
Note: m: male, f: female, S: support required level 1 and 2 (Those who need no continuous care but need some support in daily life
such as help with dressing themselves), L: long-term care required for their daily living level 1-5 (Those who need continuous
care because of being bedridden, dementia, etc.)
Figure 1. Body-weight squat exercise
Body-weight-squat exercise using a standard chair (seat height 43 cm).
Body-weight squat in frail older adults
anterior thigh muscle thickness, isometric maximal
knee extension torque, and static and dynamic
balance (static (SB): sway velocity (SV) standing on
ˆrm or foam surfaces with eyes open or closed;
dynamic (DB): limits of stability). These measure-
ments were conducted before and after the 12-week
intervention. Throughout the study, the same tech-
nician conducted all data collection and analysis.
2.3. Method for measurement
2.3.1. KET
KET during isometric maximal voluntary contrac-
tion (MVC) was measured using a specially designed
dynamometer (Takei, Niigata, Japan) with tension /
compression load cells (LUR-A-SAI, Kyowa,
Tokyo, Japan). The right leg was measured for all
participants. The participants sat on the dynamome-
ter at 90 degrees of hip and knee joint ‰exion (full
0 degree). The participant's hip was ˆx-
ed by a non-elastic belt to prevent postural change.
Torque data from each trial were ampliˆed using a
strain ampliˆer (DPM-751A, Kyowa, Tokyo,
Japan). The torque signals obtained via a 16-bit ana-
log / digital converter (PowerLab/16s, AD Instru-
ments, Sydney, Australia) were recorded on a per-
sonal computer at a sampling frequency of 1 KHz.
Participants gradually exerted muscle force from
rest to maximum over 5 sec and then sustained max-
imal exertion for approximately 2 sec. Before the
maximal testing, participants were asked to exert
submaximal muscle force to become familiar with
the test procedure. Participants performed 2 trials
with a 3-min rest between trials to exclude the in-
‰uence of fatigue. The highest value among the tri-
als was used for analysis. The KET was expressed
relative to body mass (KET/BM). This procedure
has been described by Fujita et al. (2011) and
Figure 2. Thigh muscle thickness assessed by B-mode ultrasound
Muscle thickness of the anterior thigh was measured as the distance between the fat-muscle tissue and muscle-bone
interface by a B-mode ultrasound with a 6 MHz linear scanner.
Eiji Fujita, et al.
Yoshitake et al. (2011).
2.3.2. Muscle thickness (MT)
MT of the anterior thigh was measured as the dis-
tance between the fat-muscle tissue and muscle-bone
interface by a B-mode ultrasound (Mirucube,
Global health, Kanagawa, Japan) with a linear scan-
ner. The right leg was measured for all participants.
During ultrasound measurements, participants
remained in a standing position with their legs and
arms straight and muscles relaxed as described previ-
ously (Ishida et al., 1995). The anthropometric loca-
tion of the measurement site was precisely located
and marked on the anterior surface at the midline of
the femoral length (the distance from the greater
trochanter of the femur to articular cleft between the
femur and tibial condyles). A transducer with a
6MHz scanning head was placed perpendicular to
the underlying muscle and bone tissues. The scan-
ning head was coated with ultrasonic gel, which
provided acoustic contact without depressing the
dermal surface. The ultrasonographic images were
analyzed by dedicated analytical software (Mirucube
was measured to the nearest 0.1 mm. One examiner
performed the muscle thickness measurements
throughout this study (Figure 2). The measurements
were taken with a vernier caliper to the nearest 0.1
mm. The intraclass correlation coe‹cients for the
tissue thickness measurements on two diŠerent days
were 0.99 to1.00 for MT (Takeshima et al., 2014).
The accuracy and test-retest repeatability of the
muscle thickness measurements have also been
established in prior studies (Miyatani et al., 2003;
Sanada, et al., 2006).
2.3.3. Static (SB) and dynamic (DB) balance tests
A Balance Master Platform System (NeuroCom
International, Oregon, USA) was used to measure
SB and DB (Rogers et al., 2003). SB measures were
taken while standing on diŠerent surfaces with the
eyes open or closed, and on diŠerent of surface con-
ditions (ˆrm or with foam pad). In this study, the
Clinical Test of Sensory Interaction for Balance us-
ing the Balance Master Platform System was used as
a test of postural SV that was designed to measure
the in‰uence of sensory input on balance (Nashner
and McCollum, 1985). Composite SV (SVcomp)
scores were calculated based on each sway velocity
condition as an index of SB. The test required the
participant to stand: (a) on a ‰at surface with the
eyes open (SVcomp1); (b) on a ‰at surface with the
eyes closed (SVcomp2); (c) on thick foam with the
eyes open (SVcomp3); and (d) on thick foam with
the eyes closed (SVcomp4). The force platform was
marked to maintain consistency in foot placement.
For each stance, the participant stood with their eyes
at the horizon and their arms at the sides in a neutral
position. Trials required 10 sec of data collection
(Figure 3-a).
DB was determined using the limits of stability
(LOS) assessment in which 8 targets appeared
around a center square at 0 (forward), 45, 90 (right),
135, 180 (back), 225, 270 (left), and 315 degrees
(Figure 3-b). Center of pressure (COP) appeared on
a monitor as a human-shaped cursor and moved as
participants shifted their weight toward an identiˆed
target, holding the position for 5 sec. Each LOS trial
measured endpoint (EPE) and maximum excursion
(MXE). EPE ends when the COP movement ˆrst
ceases progression toward the target. EPE was ex-
Figure 3. Static and dynamic balance tests with the Balance Master Platform System
Static balance was quantiˆed using postural sway velocity while standing on diŠerent surfaces (ˆrm or with foam
pad) with the eyes open or closed (a). Dynamic balance was determined using the limits of stability assessment in 8
directions located around a center target as the starting point at 0 (forward), 45, 90 (right), 135, 180 (back), 225,
270 (left), and 315 degrees (b).
Body-weight squat in frail older adults
pressed as a percentage of the distance to the target.
Hence, a participant whose initial movement ends
precisely at the target had an EPE of 100
initial attempts were substantially short of the tar-
get, most people initiated additional movements af-
ter the EPE was recorded. To represent this addi-
tional movement and COP excursion, an additional
measurement, the MXE was used. The MXE was the
maximum distance the COP was displaced toward
the target over the entire duration of the trial
(Rogers, et al., 2003). MXE was also expressed as a
percentage of the distance to the target. Four direc-
tions (forward, back, right and left) and composite
EPE and MXE scores were calculated based on
movements toward all 8 targets. These scores of
reaction time (RT), movement velocity (MVL), and
directional control (DC) were also used. RT was
time in seconds between the signal to move and the
initiation of movement. MVL was body tilt velocity
and calculated based on the average speed of COP
movement between 5
and 95
of the distance to
the primary endpoint using one's height as a refer-
ence and expressed in degrees per sec. Directional
control, expressed as percent, was based on 100
being a straight line from the initial center of pres-
sure to the intended target. Because the participants
were asked to move quickly, rapid reaction time and
greater speed was desirable, but participants must
also have been able to control the movement in the
intended direction.
The SB and DB tests were administered in a single
testing session on the same days. A 3-minute rest in-
terval was provided between each test. Following
verbal instruction and demonstration by the tester,
participants completed one practice trial and one
test trial while barefoot. There were no unsuccessful
trials for these tests.
2.4. Statistical analysis
Descriptive data are expressed as means and stan-
dard deviations (SDs). Pre- and post-test compari-
sons were performed using dependent t-tests. EŠect
size [ES] was also calculated for each test. Cohen's
deˆnition of small, medium and large ESs (ES
0.5, and 0.8, respectively) was used (Cohen, 1988).
A probability value of less than 0.05 was considered
statistically signiˆcant. All data were analyzed using
Table 2 Body mass, thigh girth, muscle thickness, and
strength at pre- and post- assessment
Measurements Pre- Post- p-value ES
Body mass (kg) 57.4
11.4 56.5
11.1 0.036*0.53
Thigh girth (cm) 44.6
4.3 44.4
4.1 0.328 (n.s.) 0.26
MT (mm) 29.2
5.8 31.0
5.4 0.007** 0.65
KET (Nm) 67.3
21.1 73.9
24.0 0.010** 0.63
KET/BM (Nm/kg) 1.19
0.34 1.32
0.4 0.003** 0.69
Note: MT: muscle thickness, KET: knee extension torque,
KET/BM: KET relative to body mass, **:
0.01, *:
0.05, n.s.: not signiˆcant
Table 3 Static balance at pre- and post- assessment
Measurements Pre- Post- p-value ES
EO-Firm (deg/sec) 0.41
0.26 0.31
0.13 0.042*0.51
EC-Firm (deg/sec) 0.57
0.22 0.57
0.23 0.705 (n.s.) 0.10
EO-Foam (deg/sec) 1.24
0.79 1.03
0.40 0.129 (n.s.) 0.41
EC-Foam (deg/sec) 3.94
1.90 3.96
1.57 0.969 (n.s.) 0.11
Note: EO: eyes open, EC: eyes closed, Firm: ˆrm surface,
Foam: foam surface, *:
0.05, n.s.: not signiˆcant
Eiji Fujita, et al.
SPSS ver. 15.0 for Windows statistical software
(SPSS Inc., Tokyo, Japan).
3. Results
All participants continued the current exercise
program with no incidence of injury during the
study and no participant declined to participate in
the intervention. Mean attendance rate for this exer-
cise group was 93.1
Following the intervention, participants sig-
niˆcantly (
0.05) decreased body mass by 1.6
11.4 to 56.5
11.1 kg, ES
0.53), and sig-
niˆcantly increased KET by 9.8
21.1 to
24.0 Nm, ES
0.63) and KET/BM by 10.9
0.34 to 1.32
0.38 Nm/kg, ES
0.69) (Table
2). However, there were no signiˆcant correlation
between KET/BM before the intervention and the
relative changes after the intervention. Apart from
that, thigh girth did not change, thigh muscle thick-
ness signiˆcantly increased by 6.2
5.8 mm
to 31.0
5.4 mm). There were no appreciable
changes in DB nor in SB. However, SV standing on
a ˆrm surface with the eyes open improved by
0.25 to 0.31
0.13 mm/sec) (Tables 3
and 4).
4. Discussion
The purpose of the present study was to evaluate
the eŠects of a 12-week group-based body-weight
squat exercise program on muscle mass, muscle
strength, and balance in physically frail community-
dwelling older men and women. The 12-week pro-
gram signiˆcantly decreased body mass by 1.6
0.53), increased KET by 9.8
0.63), and in-
creased KET/BM by 10.9
0.69). Moreover,
although thigh girth did not change, thigh muscle
thickness did increase by 6.2
0.65). These
results suggest that performing chair squat using
body-weight as resistanceiseŠectiveinimproving
muscular strength and muscle mass in physically
frail older adults.
A government-supported nursing-care insurance
system exists in Japan that provides inexpensive care
to older adults who utilize the program. Although it
is a good system, it does not entail a component of
physical activity as exercise machines are expensive
and space is limited in day centers and nursing
homes. The results of the present study suggest that
an exercise program consisting of body-weight exer-
cises is eŠective in improving strength and therefore
could be incorporated into this system as it is inex-
pensive and requires only a chair.
Mean attendance rate for the exercise group was
. Previous studies have suggested that 50
people who begin an exercise program discontinue
within 6 months (Hong et al., 2008; Medina-
Mirapeix et al., 2009; Kallings, et al., 2009). An
adherence level of at least 80
to 85
is recom-
mended if an intervention is to have a meaningful
eŠect and therapeutic value (Pisters et al., 2010).
Although the present study was only 12 weeks in
duration, it appears that adherence was su‹ciently
high and may be, in part, attributed to the incorpo-
ration of group-based exercise that incorporated
singing. Further study is needed to assess the psy-
chological parameters that contribute to the high
attendance associated with this program.
In general, the relative improvement ratio from
training can be considered to have greater impact on
muscle in participants with low ˆtness levels, such as
those in this study, as they are starting at a func-
tional level at which they have di‹culty performing
activities of daily living. In addition, Fujita et al.
(2011) reported that the activity level of the quad-
riceps femoris during body-weight-based squat
Table 4 Dynamic balance at pre- and post- assessment
Measurements Pre- Post- p-value ES
RT (sec)
Forward 1.22
0.42 0.95
0.27 0.058 (n.s.) 0.48
Back 0.95
0.40 0.87
0.25 0.205 (n.s.) 0.34
Right 1.08
0.41 0.95
0.34 0.232 (n.s.) 0.06
Left 1.04
0.50 0.92
0.29 0.447 (n.s.) 0.21
Comp 1.07
0.37 0.92
0.24 0.118 (n.s.) 0.41
MVL (deg/sec)
Forward 2.06
0.69 2.16
0.74 0.655 (n.s.) 0.12
Back 1.43
0.70 1.87
0.75 0.036*0.53
Right 3.11
1.28 3.91
2.06 0.200 (n.s.) 0.05
Left 2.91
1.46 3.17
1.01 0.551 (n.s.) 0.16
Comp 2.39
0.91 2.78
0.96 0.236 (n.s.) 0.31
Forward 44.13
15.84 45.67
11.39 0.651 (n.s.) 0.12
Back 37.40
16.75 39.93
16.51 0.522 (n.s.) 0.17
Right 64.53
19.31 77.73
20.56 0.039*0.52
Left 62.87
19.24 71.47
18.99 0.186 (n.s.) 0.35
Comp 52.33
14.20 59.00
11.97 0.073 (n.s.) 0.46
Forward 60.60
14.62 60.87
16.51 0.929 (n.s.) 0.24
Back 49.00
20.54 54.93
19.28 0.206 (n.s.) 0.34
Right 84.67
17.12 96.13
17.92 0.022*0.57
Left 81.00
20.48 86.93
18.53 0.297 (n.s.) 0.28
Comp 68.87
15.13 74.87
12.94 0.065 (n.s.) 0.47
Forward 77.73
9.68 71.60
13.72 0.094 (n.s.) 0.43
Back 59.20
23.45 63.73
18.37 0.063 (n.s.) 0.48
Right 74.27
11.40 74.80
8.16 0.784 (n.s.) 0.08
Left 70.60
14.78 72.00
10.41 0.707 (n.s.) 0.10
Comp 70.60
12.84 70.60
9.18 1.000 (n.s.) 0.00
Note: RT: reaction time, MVL: movement velocity, EPE: endpoint excursion, MXE: maximum excur-
sion, DCL: directional control, Comp: composite value, *:
0.05, n.s.: not signiˆcant
Body-weight squat in frail older adults
movement is in‰uenced by the force generation
capability during the squat movement. For individu-
als with a KET/BM less than 1.9 Nm/kg, body-
weight-based squat movement is considered to be a
high-intensity activity. All of the participants in the
present study were below this threshold both before
and after the intervention suggesting that they were
performing a high-intensity exercise throughout the
Yoshitake et al. (2011) have shown that body-
weight-based squat exercise increased KET/BM by
0.63 to 2.42
0.58 Nm/kg) in healthy
middle-aged and older women. In the current study,
the gain in KET/BM was lower (10.9
study of Yoshitake et al. (2011). A plausible reason
for that is the frequency of exercise in the current
study was only twice a week while the study of
Yoshitake et al. (2011) utilized a frequency of at
least six days per week. Although Nakamura et al.
(2007) reported that an exercise intervention of only
twice per week was not su‹cient to induce sig-
niˆcant improvements, participants in the current
study did improve functional ˆtness signiˆcantly. It
remains to be determined if performing squat exer-
cises in greater volume (e.g., more sets, greater
training frequency, longer training duration) would
result in additional increases in the outcomes as-
sessed in this study. Further research is needed to
clarify this point.
According to Yoshitake et al. (2011), the eŠect of
training on lower muscle strength using body mass
depends on the baseline value before intervention.
This is because the level of muscle activity in the
quadriceps during the squat movement is inversely
correlated with KET/BM (Takai et al., 2008; Fujita
et al., 2011), so the lower the KET/BM, the higher
the intensity of exercise becomes. The results of the
current study did not show a signiˆcant correlation
between KET/BM before the intervention and the
relative changes after the intervention. One explana-
tion for this may be that the number of subjects in
this study was smaller than that in the previous study
by Yoshitake et al. (2011) and the KET/BW values
were within a narrower range (0.73 to 1.89 Nm/kg)
Eiji Fujita, et al.
than the studies of Takai et al. (2008) and Yoshitake
et al. (2011).
Squat and sit-to-stand movements are accompa-
nied by forward and backward weight shift in the
sagittal plane (Schenkmen et al., 1990). Therefore,
we expected that if squat training were to have an
eŠect on balance that such improvements would
appear in the forward and backward directions.
Although strength improved, there were no appreci-
able changes in DB nor in SB, except SV standing on
a ˆrm surface with the eyes open improved by
. In many cases, falls are caused by a loss of
balance (Nickens, 1985; Tinetti and Speechley,
1989). During both static and dynamic balance,
posture is controlled by the detection of distur-
bances to the center of gravity and the initiation of
appropriate responses to return the body to a stable
position. This is a complex process controlled to a
large extent by the visual, somatosensory, and ves-
tibular systems. In addition, the muscular system
contributes to balance control since all body move-
ments are produced via contraction of skeletal mus-
cles. With increasing age, there is a decrease in sen-
sory function (Wolfson et al., 1992; Era et al., 2006)
and a decrease in muscle strength (Porter et al.,
1995). Slobounov et al. (1998) measured postural
sway in older adults aged 67 to 92 years and found
that postural sway, with eyes open and closed, in-
creased with age, but was aŠected to a much greater
extent when visual cues were removed. Hasan et al.
(1990) investigated changes in postural sway in
women over the age of 65 during eyes open double
stance, eyes open single stance, eyes closed double
stance, and eyes closed single stance. The velocity of
sway increased when the visual cues were removed
and when the feet were positioned to reduce the size
of the base. Therefore, the eŠect of vision on postur-
al sway may become increasingly important with
age. Furthermore, a reduced base of support (e.g.,
when the feet are in the semi-tandem, tandem, or
unilateral positions as occurs during walking) may
increase the risk for suŠering a fall, especially in
dimly illuminated conditions that compromise visual
sensation. Although Takeshima et al. (2013) have
shown that an age-related decline exists for both SB
and DB, we have also shown that customized
balance training can improve dynamic balance
(Narita et al., 2015), so it is possible that the inclu-
sion of some balance training activities with the
squat exercises used in the current study may im-
prove muscle strength, muscle thickness, and
postural balance in frail older adults which could
contribute to the prevention of falls. Many balance
exercises can be performed with only the use of a
chair and could easily be performed in conjunction
with body-weight squats exercises without requiring
additional space or equipment.
A limitation of this study is the lack of a control
group. Although this is appropriate and acceptable
for a quasi-experimental design, a stronger defense
of the intervention would be made with a controlled,
randomized approach.
In conclusion, group-based body-weight squat
exercise performed twice weekly for 12 weeks does
improve muscle strength and muscle thickness in
physically frail older adults. This program is eŠec-
tive, simple and inexpensive, making it suitable for
this population.
The authors are grateful to the subjects who participated in
this study.
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Eiji Fujita
Senior Assistant Professor, Department
of Sport and Life Science, National In-
stitute of Fitness and Sports in Kanoya
1 Shiromizu, Kanoya, Kagoshima 891-2393 JAPAN
Brief Biographical History and Work
Eiji Fujita is the Senior Associate Professor at Department of
Sport and Life Science, National Institute of Fitness and Sports
in Kanoya (2008-). He obtained his Ph.D. at National Institute
of Fitness and Sports in Kanoya in 2012. His research interests
are on health promotion, exercise gerontology and prevention
of sports injury.
Fujita E, Kanehisa H, Yoshitake Y, Fukunaga T, Nishizono H.
Association between knee extensor strength and EMG activities
during squat movement, Medicine & Science in Sports & Exer-
cise, 43(12): 2328-2334, 2011.
Membership in Learned Societies
Japan Society of Physical Education, Health and Sport
Japan Society of Physical Fitness and Sports Medicine
Japanese Academy of Budo
... This exercise program was also based on a study by Fujita et al. 18 , where frail older adults engaged in a repeated sit-to-stand exercise. The authors showed that frail individuals were able to safely execute 48 complete repetitions with a short pause between bouts. ...
... The results obtained from the 30-second CST showed that the HBEG performed a higher number of repetitions than the CG (63% higher, or additional ~6 repetitions) (Figure 2A). These results are consistent with the findings of the study conducted by Fujita et al. 18,20 . These authors performed 12 weeks of physical training in institutionalized # Statistical difference versus CG, *statistical difference versus 4W and $ statistical difference versus Pre-training. ...
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Objective to determine the effects of a simple home-based exercise program on functional capacity and perceived loneliness of older adults in lockdown due to the COVID-19 pandemic. Method Twenty-nine volunteers were randomly divided into two groups: (1) control group (CG); and (2) home-based exercise group (HBEG). Lower limb muscle strength, functional capacity, and perceived loneliness were assessed at baseline (pre-test), 4 weeks, and 8 weeks (post-test) using the Chair Standing Test (CST), Gait Speed Test (GST), Timed Up and Go test (TUG), and Perceived Loneliness Scale (PLS). Results The number of repetitions on the CST differed statistically between the groups (CG vs. HBEP, p=0.006) and among timepoints (Pre vs. 4W vs. 8W, p=0.043.). In the CG group, TUG test completion time was statistically lower at baseline than at 8 weeks (p=0.021) (pre 12.0±5.9 s vs. 8W 12.7±6.5 s). There was no statistical difference in TUG time in the HBEG. No statistical differences were found on the GST and PSL between groups or among timepoints. Conclusion The home-based exercise program improved general functional capacity after 8 weeks of training, but perceived loneliness and gait speed were unchanged in the older adults experiencing lockdown due to the COVID-19 pandemic.
... Some bodyweight exercises have been shown to benefit not just the young, but the elderly as well [15] . Older people undertaking bodyweight exercises benefit through increased muscle mass, increased mobility, increased bone density and decreased depression and improved sleep habits [16,17] . ...
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Due to the corona virus outbreak, several countries in universe are facing the problem of major lockdowns including India. The pandemic has forced many people to stay at home and self-isolate for a period of time. COVID-19 seems to be having a major impact on physical activity behaviors worldwide. The present study is going to highlight physical activity awareness during COVID-19 lockdown period. It is very important for an individual, family and society also. It presents on how to people are facing the challenges like as psychological, physical, economic and social in their routine life in lockdown period. It is very important to maintain the psychological and physical condition in this situation. Physical activity is good for your body, mind and spirit especially during such stressful situations and it will also ensure good overall health. So, engaging in day-today physical activity at home is better way to maintain the physical and psychological conditions during lockdown period.
... As such, there is a need to develop pragmatic and accessible RET interventions that can effectively support the maintenance or, indeed, enhancement of muscle mass, strength and function in older age (Timmons et al., 2020). Elastic resistance bands (EB) and bodyweight (BW) lifting are proficient methods of RET, capable of increasing muscle mass, strength and functional capacity in community-dwelling (Fujita et al., 2016;Krause et al., 2019), institutionalized (Fujita et al., 2019;Furtado et al., 2020), sarcopenic-obese older adults (Liao et al., 2018), and older adults with cognitive impairment (Chupel et al., 2017). Compared with traditional machine-based (MN) RET, EB have also been shown to generate an 'ascending' (or 'linear variable') resistance training load, providing an increasing tensile load due to the stretch properties of the EB (Fuentes et al., 2019). ...
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Background Understanding the root cause of the age-related impairment in muscle adaptive remodelling with resistance exercise training (RET) and developing pragmatic and accessible resistance exercise for older adults, are essential research directives. Methods We sought to determine whether indices of quadriceps muscle EMG activity in response to different modes of resistance exercise training (RET) and activities of daily living (ADL), differed between 15 healthy younger (25 ± 3 years) and 15 older (70 ± 5 years) adults. On four separate days, participants completed a maximal voluntary contraction (MVC) of the knee extensors, followed by a 15 m walking task, stair climbing task (i.e. ADL) and lower-limb RET through body-weight squats (BW-RET) and seated knee extensions on a machine (MN-RET) or via elastic bands (EB-RET). Quadriceps electromyography (EMG) was measured throughout all tasks to provide indirect estimates of changes in muscle activity. Results MVC was significantly greater in young vs. older adults (Young: 256 ± 72 vs. Old: 137 ± 48 N·m, P < 0.001). EMG activity during all exercise tasks was significantly higher in older vs. younger adults when expressed relative to maximal EMG achieved during MVC (P < 0.01, for all). In addition, relative quadriceps muscle EMG activity was significantly greater in EB-RET (Young: 20.3 ± 8.7 vs. Old: 37.0 ± 10.7%) and MN-RET (Young: 22.9 ± 10.3, vs. Old: 37.8 ± 10.8%) compared with BW-RET (Young: 8.6 ± 2.9 vs. Old: 27.0 ± 9.3%), in young and older adults (P < 0.001). However, there was no significant difference in quadriceps EMG between EB-RET and MN-RET (P > 0.05). Conclusions In conclusion, relative quadriceps muscle EMG activity was higher across a range of activities/exercise modes in older vs. younger adults. The similar quadriceps muscle EMG activity between EB-RET and MN-RET provides a platform for detailed investigation of the neuromuscular and muscle metabolic responses to such pragmatic forms of RET to strengthen the evidence-base for this mode of RET as a potential countermeasure to sarcopenia.
... 5 Previous studies have shown that elderly individuals who were physically active generally possessed a higher HRQoL than those who were more inactive, 6 with others uncovering that muscle strength was related to factors like physical fitness, disability and mortality. [7][8][9] However, studies on the association between muscle strengths and limitations of this study ► Only a few studies have been conducted on the association between muscle strength and the health-related quality of life (HRQoL) for the Chinese rural elderly population, especially among those living in rural areas; whereas this study used a large sample population-based cross-sectional design in order to research this association within this demographic. ► In addition to upper limb muscle strength, lower limb muscle strength was also included in this study, with the association between muscle strength and HRQoL being analysed between different subgroups. ...
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Objective To investigate the relationship between upper and lower limb muscle strength and the health-related quality of life (HRQoL) of a Chinese rural, elderly population. Design A population-based, cross-sectional study. Setting Miyun, Beijing, China. Participants The participants of this study were 2083 (834 men and 1249 women) older adults from a rural area, (average age of ≥60 years), living in Miyun county, located on the outskirts of Beijing. Data were collected between May and October 2014. Handgrip strength and timed up and go tests (TUGT) were conducted to measure the muscle strength of their upper and lower limbs, respectively. The Euro Quality of Life (Euroqol) (EQ-5D)-Visual Analogue Scale was used to evaluate participants’ HRQoL. Results A significant association between handgrip strength and the EQ-5D index (β=0.015 per SD, 95% CI: 0.008 to 0.023, p<0.001) was discovered, following adjustments. The association between handgrip strength and the EQ-5D index in the ≥80 years group was found to be stronger than that of the 60–79 years group, following adjustment (β per SD: 0.013 vs 0.035). Similar results were observed when comparing the non-chronic disease group, in terms of TUGT time, against those with chronic diseases. Conclusions There was a significant relationship between muscle strength (measured via handgrip strength and TUGT time) and HRQoL (measured via EQ-5D index and VAS score) in the Chinese rural elderly population. Furthermore, this relationship was stronger in the older population (aged ≥80 years), and in those participants diagnosed with chronic diseases.
... The repeated sit-to-stand exercise undertaken in this trial significantly increased KET/BM in the physically frail participants. This agrees with our prior report (Fujita et al., 2016) which adopted a similar intervention program in frail elders, and extends those findings by examining the muscular activity levels during the squat task. Values for KET/BM of our participants were considerably less than values we have previously reported for non-frail older Japanese adults and middle-aged adults (Fujita et al., 2011) and substantially improved by 19.4% with only 4 weeks training and was 23.9% greater at 12 weeks. ...
Purpose: To examine the effect of a conditioning program consisting of repeated sit-to-stand exercise on knee extensor strength and muscular activities during body mass-based squat movement in physically frail elders. Methods: Fourteen men and women aged 75 to 88 years who used the long-term care insurance system participated in the 12-week training program (48 reps/session, 3 sessions/week). Isometric knee extension torque (KET) during a maximum voluntary contraction (MVC) and electromyogram (EMG) activities of the rectus femoris and vastus lateralis muscles during the MVC and a body mass-based squat task were determined at baseline, and following 4 and 12 weeks training. KET was expressed relative to body mass (KET/BM) and EMG activities during the squat task were normalized to that during a MVC and averaged (QF %EMGmax). Results: KET/BM increased from 1.07 ± 0.28 Nm/kg at baseline to 1.26 ± 0.26 Nm/kg at week 4 and 1.31 ± 0.28 Nm/kg at week 12 (P < 0.001), and QF %EMGmax decreased from 67.2 ± 17.2% to 49.3% at week 4 (P < 0.001) and 43.5 ± 7.7% at week 12 (P = 0.016). At each of the three measurement time points KET/BM was inversely correlated with QF %EMGmax (r = -0.78 to -0.86, P ≤ 0.001). Conclusion: For physically frail elders, a short-term conditioning program consisting of repeated sit-to-stand exercise is effective in increasing knee extensor strength and reducing the muscular effort required for lowering and raising the body.
Full-text available
Resumo Objetivo Determinar os efeitos de um programa de exercício físico remoto realizado em ambiente domiciliar na capacidade funcional e percepção de solidão de idosos socialmente isolados, devido a pandemia da covid-19. Método Vinte e nove (29) idosos foram divididos aleatoriamente em dois grupos: (1) grupo controle (GC) e grupo de exercício em ambiente domiciliar (GEAD). A força muscular dos membros inferiores, a capacidade funcional e a percepção de solidão foram avaliadas no início (pré-teste), 4 semanas e 8 semanas (pós-teste). As avaliações consistiram no teste de sentar e levantar da cadeira (TSL), teste de velocidade de marcha (TVM), Timed Up and Go (TUG) e teste de percepção de solidão (TPS). Resultados O número de repetições durante o TSL foi estatisticamente diferente entre os grupos (GC vs. GEAD, p=0,006 e entre os momentos (Pré vs. 4S vs. 8S, p=0,043.). No teste de TUG, dentro do GC, o momento pré foi estatisticamente menor em relação ao momento de 8 semanas (p<0,021), indicando maior tempo para completar o TUG (pré 12,0±5,9 s vs. 8W 12,7±6,5 s). Essa mesma comparação não foi estatisticamente diferente dentro do GEAD. Não houve diferenças estatísticas no TVM e TPS entre os grupos e entre os momentos. Conclusão O programa de exercício domiciliar melhorou a capacidade funcional após 8 semanas de treinamento, mas a percepção de solidão e o teste de velocidade de marcha não foram afetados pelo programa de exercícios físico remoto em idosos isolados devido à pandemia de covid-19.
The benefit of body weight resistance exercise with slow movement (BWRE-slow) for muscle function is well-documented, but not for energy metabolism. We aimed to examine physiological responses [e.g., energy expenditure (EE), respiratory exchange ratio (RER), and blood lactate (La)] during and after BWRE-slow compared to EE-matched treadmill walking (TW). Eight healthy young men (23.4 ± 1.8 years old, 171.2 ± 6.2 cm, 63.0 ± 4.8 kg) performed squat, push-up, lunge, heel-raise, hip-lift, and crunch exercises with BWRE-slow modality. Both the concentric and eccentric phases were set to 3 s. A total of three sets (10 repetitions) with 30 s rest between sets were performed for each exercise (26.5 min). On another day, subjects walked on a treadmill for 26.5 min during which EE during exercise was matched to that of BWRE-slow with the researcher controlling the treadmill speed manually. The time course changes of EE and RER were measured. The EE during exercise for BWRE-slow (92.6 ± 16.0 kcal for 26.5 min) was not significantly different from the EE during exercise for TW (95.5 ± 14.1 kcal, p = 0.36). BWRE-slow elicited greater recovery EE (40.55 ± 3.88 kcal for 30 min) than TW (37.61 ± 3.19 kcal, p = 0.029). RER was significantly higher in BWRE-slow during and 0-5 min after exercise, but became significantly lower during 25-30 min after exercise, suggesting greater lipid oxidation was induced about 30 min after exercise in BWRE-slow compared to TW. We also indicated that BWRE-slow has 3.1 metabolic equivalents in average, which is categorized as moderate-intensity physical activity.
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The present study aimed to clarify age and gender differences in the electromyographic (EMG) activity levels of lower limb muscles during daily physical actions. Forty young and 22 elderly individuals performed five physical actions, i.e. normal walking, ascending and descending stairs, standing up from and sitting onto a chair, and a calf raise exercise. The surface electromyograms (EMGs) during these actions were recorded from the vastus medialis, rectus femoris, vastus latelalis, lateral gastrocnemius, medial gastrocnemius, and soleus muscles using a portable EMG recording apparatus. For the prescribed actions, the mean activity levels of the quadriceps femoris (QF%EMG) and triceps surae (TS%EMG) muscles were quantified and expressed as the relative values (%EMG) to that during the maximal voluntary isometric contraction (MVC). The %EMG values of QF and TS significantly differed among actions, with significant influences of age and gender. The %EMG of each of QF and TS was negatively correlated to MVC torque relative to body weight, developed in knee extension and ankle plantar flexion, suggesting that the observed age and gender differences in %EMG could be partially attributed to those in torque generation capabilities. Thus, the present findings indicate that the individuals with lower maximal isometric joint torque per body weight demonstrate higher muscular activity levels during daily physical actions. For these populations, the daily physical actions examined here may be resistance exercises for improving the torque generation capability of lower limb muscles.
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Falls represent a major public health problem for older adults, and loss of balance (LOS) abilities is one of the primary causes of falls. Previous studies have shown that balance training is effective in improving physical function and decreasing risk of falls. However, little attention has been given specifically to balance training in older adults with very poor balance. The purpose of this study was to determine the effect of a 12-week customized balance exercise program on LOS for community-dwelling older women with poor balance ability. Twenty-four older women with poor balance (composite maximum excursion [MXEcomp] score of less than 70% based on Limits of Stability) were divided into an exercise group and control group. After 12 weeks of balance exercises, mean MXEcomp improved (p < .05) from 58.6% to 79.0% in the exercise group. EPEcomp (composite endpoint excursion), RTcomp (composite reaction time), SVcomp3 (composite sway velocity on thick foam with the eyes open), UG (up and go) also improved, but the functional reach and other static balance indexes did not change. These results indicated that balance training allows older adults with poor balance to improve dynamic balance ability and potentially reduce risk for falls.
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To clarify the progression of muscle loss in nursing home residents, frail women (n=16; age: 85 ± 9 yr; residence time 764 days) were assessed for physical activity, caloric intake, and site-specific muscle thickness (MTH) and subcutaneous fat thickness (SFT) using B-mode ultrasound at 9 anatomical sites at 4 intervals over one year. Height, body weight and BMI did not change. Physical activity (246 steps/day) and nutritional intake (1441 kcal, 60.3 g protein/day) were unaltered throughout the study. Subjects experienced a significant, progressive loss of muscle indicated by decrements in anterior-upper arm (20%), posterior-upper arm (25%) abdomen (20%) subscapular (33%), anterior thigh (15%), posterior thigh (22%), anterior-lower leg (11%), posterior-lower leg (13%), and forearm (15%) MTH. At study inception, prevalence of sarcopenia was related to muscle loss in the upper leg, while upper-body muscle wasting contributed to sarcopenia and was unrelated to physical activity, nutritional input, or duration of residence.
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The purpose of this study was to assess the efficacy of a home-based well-rounded exercise program (WREP) in older adults. Forty sedentary community-dwelling older adults were randomly assigned to an exercise group (n = 23; aged 62-80 yr, average: 69.2 ± 5.2; 12 men and 11 women) or a control group (n = 17; aged 63-85 yr, average: 70.1 ± 6.6; 5 men and 12 women). The exercise group performed a 12-wk WREP which included aerobic exercise (walking) on about 3 days·wk(-1) for 37 min·day(-1); elastic band-based resistance exercises for the major muscle groups on about 3 days·wk(-1) for 26 min; and flexibility exercises (stretching) on about 4 days·wk(-1) for 19 min·day(-1). General physical characteristics, functional strength (Arm Curl [AC], Chair Stand [CS]), dynamic balance and agility (Up & Go [UG]), flexibility (Back Scratch [BS], Sit & Reach [SR]), and endurance (12-min walk [12-MW]) were measured. Following the 12-wk home-based WREP, improvements were observed in AC, CS, UG, BS, SR and 12-MW for the exercise group but not for the control group. These results suggest that the home-based WREP can improve overall fitness in older adults. Key PointsWalking, elastic band exercise and stretching were prescribed as a Well-Rounded Exercise Program for older adults.By combining aerobic, resistance and flexibility exercises, a Well-Rounded Exercise Program was effective for improving endurance, functional strength, dynamic balance and agility, and flexibility.Community-based exercise classes motivated older adults to perform home-based exercises.
The purpose of the present investigation was to examine (a) the effects of upper body high-intensity strength training on muscular strength, activities of daily living (ADLs), and subjective well-being within an aging population, and (b) whether changes in strength were related to subsequent changes in subjective well-being and ADLs. The main effects of the training program were significant for all five individual muscle groups examined, indicating that subjects who participated in the strength program had greater increases in muscular strength than did controls. There was limited support for the contention that strength training enhances subjective well-being and ADLs in older adults. Strength gains were related to moderate reductions in negative affect, greater satisfaction with life, and higher ADLs. Findings are discussed in terms of design and measurement improvements, the need to focus research efforts on multiple components of fitness in relation to subjective well-being, and relations among streng...
The studied muscle loss with aging, focusing on differences due to muscle group location. Muscle thickness at nine sites-forearm, upper arm anterior and posterior, abdomen, subscapular, thigh anterior and posterior, and lower leg anterior and posterior-were determined using a brightness-mode ultrasonography in 348 Japanese men aged 20 to 79 years. Only the upper arm anterior did not show a significant effect of age. For other sites, the starting age group that significantly decreased from 20-29 yr and 30-39 yr was 40-49 yr for the forearm and abdomen, 50-59 yr for the thigh anterior, 60-69 yr for the upper arm posterior, lower leg anterior and posterior, and subscapular, and 70-79 yr for the thigh posterior. The relative reduction between the 20-29 yr and 70-79 yr groups in the muscle thickness at the abdomen and thigh anterior were greater than those in the other sites. In addition, the upper arm and thigh showed a preferential loss with aging at the posterior and anterior sites. Thus, the present results indicated that the loss of muscle thickness with aging differed between body segments and between sites within the same segment. The reasons for the site-related differences in muscle loss with aging may be attributed to age-related changes in the patterns of loading to individual muscles and/or their activations, which are encountered during daily life.