Takeshima (2002) Water-based exercise improves health-related aspects of fitness in older women

Water-based exercise improves health-
related aspects of fitness in older women
NOBUO TAKESHIMA, MICHAEL E. ROGERS, EIJI WATANABE, WILLIAM F. BRECHUE, AKIYOSHI OKADA,
TADAKI YAMADA, MOHAMMOD M. ISLAM, and JYUNICHIROU HAYANO
Institute of Natural Sciences, Nagoya City University, Nagoya, JAPAN; Center for Physical Activity and Aging, Wichita
State University, Wichita, KS; Graduate School of Sports Science, Chukyo University, Aichi, JAPAN; Department of
Kinesiology, Indiana University, Bloomington, IN; Department of Health and Psychosocial Medicine, Aichi Medical
University, Aichi, JAPAN; and 3rd Department of Internal Medicine, Nagoya City University Medical School, Nagoya,
JAPAN
ABSTRACT
TAKESHIMA, N., M. E. ROGERS, E. WATANABE, W. F. BRECHUE, A. OKADA, T. YAMADA, M. M. ISLAM, and J.
HAYANO. Water-based exercise improves health-related aspects of fitness in older women.Med. Sci. Sports Exerc., Vol. 33, No. 3,
pp. 544 551, 2002.Purpose:The purpose of this study was to determine the physiological responses of elderly women to a
well-rounded exercise program performed in water (WEX).Methods:The participants (60 75 yr of age) were randomly divided into
a training (TR) group (N15) and a control group (N15). The TR group participated in a 12-wk supervised WEX program, 70
minday
1, 3 dwk1. The WEX consisted of 20 min of warm-up and stretching exercise, 10 min of resistance exercise, 30 min of
endurance-type exercise (walking and dancing), and 10 min of cool-down exercise.Results:The WEX led to an increase (P0.05)
in peak V
O
2(12%) and V
O2at lactate threshold (20%). Muscular strength evaluated by a hydraulic resistance machine increased
significantly at resistance dial setting 8 (slow) for knee extension (8%), knee flexion (13%), chest press (7%) and pull (11%), shoulder
press (4%) and pull (6%), and back extension (6%). Vertical jump (9%), side-stepping agility (22%), trunk extension (11%), and FEV
1.0(7%) also increased significantly. There was a significant decrease in skin-fold thickness (8%), low-density lipoprotein (LDL)
cholesterol (17%), and total cholesterol (11%). There were no significant changes in these variables in the control group.
Conclusion:These results indicate that WEX elicits significant improvements in cardiorespiratory fitness, muscular strength, body fat,
and total cholesterol in older adult women. Water-based exercise appears to be a very safe and beneficial mode of exercise that can
be performed as part of a well-rounded exercise program.Key Words:HEAD-OUT WATER IMMERSION, WELL-ROUNDED
EXERCISE, ELDERLY
E
lderly individuals can benefit from a properly de-
signed aerobic exercise program (4,18,26). Recently,
the basic exercise guidelines recommended by the
American College of Sports Medicine (ACSM) for healthy
adults and the elderly place additional emphasis on resis-
tance exercise (1,2). Given the specific nature of adaptation
to exercise and the need for maintaining muscle mass,
muscular strength, and flexibility throughout life, a well-
rounded training program consisting of resistance, aerobic,
and flexibility exercises is highly recommended by the
ACSM.
Exercising in water has become increasingly popular, and
it has been reported that water exercise (WEX) for older
individuals is therapeutically beneficial (25,34). The WEX
is also a viable form of conditioning for those who are
afflicted with orthopedic disabilities (25). Furthermore,
overweight persons find chest-deep water to be a motivating
factor because their bodies are hidden from the view of
others while performing the training (22). The dual effectsof buoyancy and resistance create an environment that re-
quires high levels of energy expenditure with relatively little
movement or strain on low-joint extremities. The water is an
equalizing medium; its gravity-minimizing nature reduces
compressive joint forces, providing a better exercise envi-
ronment for patients with arthritis, back pain, osteoporosis,
or other medical conditions that may restrict training on
land. It has been reported that the resistance provided by
water increases the energy cost of certain types of work
(10,11). For example, V
O
2is higher while ambulating in
waist-deep water compared with walking on a treadmill at
the same speed (12).
It has been reported that walking in waist-deep to chest-
deep water and participating in water aerobics provide suf-
ficient load to develop cardiorespiratory fitness in young
and middle-aged adults (28). Reports are also available on
the acute physiological responses of WEX on cardiovascu-
lar regulation, as well as the renal-endocrine response dur-
ing water immersion at rest and during water exercise in
older adults (9,12,32). However, there are few reports avail-
able to describe the effect of long-term WEX in older adults.
Thus, although it appears that WEX may be a suitable
exercise modality for elderly individuals, little is known
about the general physiological adaptations in older adults
who regularly engage in WEX. Therefore, on the basis of
0195-9131023303-0544$3.000
MEDICINE & SCIENCE IN SPORTS & EXERCISE
Copyright 2002 by the American College of Sports Medicine
Submitted for publication November 2000.
Accepted for publication June 2001.
544

the promising nature of WEX and the ACSM recommen-
dations that advocate well-rounded exercise programs, this
study was conducted to determine the physiological re-
sponses of older adult women to a well-rounded exercise
program performed in the water.
METHODS
Participants.In response to a local newspaper adver-
tisement, 45 elderly women volunteered to participate in the
study. Before acceptance into the study, a medical exami-
nation was performed and questionnaires regarding medical
history and physical activity were completed. Fifteen vol-
unteers were excluded on the basis of the medical exami-
nation report or the questionnaires because they were taking
medication prescribed for hypertension, hypercholesterol-
emia, or hormone replacement therapy; had diagnosed cor-
onary heart disease (CHD); or were participating in regular
physical activity beyond that required for normal daily liv-
ing. The remaining 30 volunteers (6075 yr of age) were
sedentary but apparently healthy. The ethical committee of
the Institute of Natural Sciences at Nagoya City University
approved the study. All participants received written and
oral instructions for the study and each gave their written
informed consent before participation.
Testing protocol.Following baseline measurements of
body composition, cardiorespiratory fitness, muscular
strength, blood lipids, and flexibility, the participants were
randomly divided into two groups: a training (TR) group (N
15) and a nonexercise control group (N15). The TR
group participated in a 12-wk WEX program. The control
group was instructed to continue their normal physical ac-
tivity patterns. All participants were asked to not change
their nutrition practices during the duration of the study.
After 12 wk, all measurements were repeated in both
groups.
After lying supine for 5 min, resting HR and blood
pressure were measured by an automated machine (Colin
Stress BP monitor, STBP-680). Using a microspirometer
(Microspiro HI-298, Chest; Colin Co., Komaki, Japan),
pulmonary function was assessed by measuring the forced
vital capacity (FVC) and forced expiratory volume in the
first second (FEV
1.0).
Skin-fold and girth measurements were taken in triplicate
on the right side of the body (8), and the median value was
used for analysis. Triceps and subscapular skin folds were
measured using a skin-fold caliper (Eiken MK-60; Meiko-
sha Co., Tokyo, Japan). The sum of the two skin folds was
used for analysis. Thigh girth was measured at the midpoint
between the inguinal crease and the proximal border of the
patella. Arm girth was measured at the midpoint between
the acromion process and the olecranon process. Girths were
measured using a nonelastic tape measure. An experienced
tester who was blind to group assignment performed all
skin-fold and girth measurements.
V
O
2maxwas determined using an incremental cycle er-
gometer (model 81E, Monark, Stockholm, Sweden) exer-
cise protocol (33). Following a warm-up, the load wasincreased by 0.25-kPa (12.5 W) increments every minute
until volitional exhaustion. Pedal rate was maintained at 50
rpm with the assistance of an auditory-visual metronome.
Where necessary, the ACSM-recommended criteria were
followed to terminate an exercise test before volitional ex-
haustion. A V
O
2maxwas accepted if oxygen uptake reached
a plateau (increased0.25 Lmin1with an increase in
workload), respiratory exchange ratio (RER) was greater
than 1.1, or predicted maximal HR (220age) was
achieved.
Measurements of V
O
2and V
CO2were made via indirect
calorimetry using the open-circuit spirometry method. Ex-
pired gas was passed through a mixing chamber and ana-
lyzed continuously (Anima Gas Analyzer Telemetry Sys-
tem, AT-1000; Anima Co., Tokyo, Japan). Gas analyzers
were calibrated immediately before and after each test with
a known concentration of oxygen and carbon dioxide. Ven-
tilation was measured with the systems ventilation module.
Heart rate was monitored (12-lead ECG; Lifescope 8, Ni-
hon-Koden Co., Tokyo, Japan) continuously throughout the
test. Blood pressure was measured by an automatic device
(Colin Stress BP monitor, STBP-680) and ratings of per-
ceived exertion (RPE) (Borgs 6- to 20-point scale) were
scored during the last 15 s of each stage of exercise.
Lactate threshold (LT) was determined from a series of
venous blood samples (1 mL each) drawn from an antecu-
bital vein every minute during exercise. The blood samples
were analyzed by an electrochemical enzymatic method
(Toyobo Lactate Analyzer, HEK-30 L, Toyobo, Tokyo,
Japan) immediately after collection. The V
O
2at LT
(V
O
2LT) was defined as the point at which the rate of
production and diffusion of lactate exceeded the rate of
removal, and was identified as the point at which lactate
concentration (La
) abruptly increased in a nonlinear
fashion (5). For discerning the nonlinear point of La
increase, the log V
O
2-log La transformation method
was used (5).
Muscle strength (peak torque) was evaluated by a hy-
draulic-resistance machine (Hydra Omintron, Henley
Healthcare Co., Sugarland, TX). The resistance produced by
this hydraulic-resistance machine is regulated by selecting
dial settings of 1 through 11 that control the diameter of the
aperture through which the hydraulic fluid passes. The ap-
erture openings range from 0.120 mm (setting 1, low resis-
tance) to 0.025 mm (setting 11, high resistance). In this
study, the machine was set at dial settings 2 (low intensity),
5 (moderate intensity), and 8 (high intensity). The partici-
pants were asked to move through their full range of motion
as rapidly and forcefully as possible. Peak torque (Nm) was
recorded for knee extensionflexion, shoulder presspull,
chest presspull, and lumbar flexionextension. These exer-
cises simulated the strength training components that were
practiced during WEX. Each exercise was performed three
times and the highest value was used for analysis.
Muscle power was evaluated using vertical jump (21).
Each participant stood with the feet 1020 cm apart on a
specially designed measuring scale (Jump Meter, T.K.K.
5106, Jump MD, Takei Scientific Instrument Co., Nigata,
WATER-BASED EXERCISE IN OLDER ADULT WOMEN Medicine & Science in Sports & Exercise
545

Japan) that consisted of a round-shaped, flat jumping board.
A measuring tape was fastened to the abdomen of the
participant and a string was tied from the measuring tape to
the center of the jumping board. The participant then
jumped as high as possible. Jumping performance was re-
corded as the distance between standing and jumping
heights determined from the tape measure. To ensure mea-
surement consistency, the same tester conducted all trials.
Agility was determined from a side-stepping test (21).
Each participant stood astride a line with a line marked at
1 m to each side. On a signal, the participant started stepping
to the left line and then returned to the starting position (one
repetition). Without pausing, the participant performed the
same task on the right side and continued moving from side
to side as quickly as possible for 20 s. The number of
repetitions completed in 20 s was recorded as the final score.
Flexibility was measured by 1) trunk flexion from a
standing position and 2) trunk extension from a prone po-
sition (21). For the trunk flexion test, each participant was
asked to stand in bare feet on a specially designed measuring
bench, placing the toes even with the front edge of the
bench. A measuring scale was attached vertically to the
front of the bench. The zero mark of the scale was fixed at
the level of the upper surface of the bench. The scale was
graduated in centimeters in both the upward and downward
directions. The upward distance from the zero mark was a
negative score and the downward distance was a positive
score. While standing on the bench, the participant was
asked to bend over and reach down as far as possible
without bouncing, while keeping the knees locked. Perfor-
mance was scored as the distance reached by the middle
fingers and held for at least 1 s. For the trunk extension test,
each participant was asked to lie pronated with the hands
clasped behind the back. An assistant held the feet to secure
the legs to the floor surface. The participant was asked to
extend the spine by lifting the shoulders and chin off the
floor as far as possible. The distance between the floor and
the chin as measured by a specially designed measuring
scale (Trunk Extension Meter, T.K.K. 5104 Extension-D,
Takei Kiki Co.) was recorded as maximal trunk extension.
Each flexibility test was performed twice and the maximum
values were used for analysis.
After an overnight fast of approximately 1214 h, a blood
sample (78 mL) was collected from an antecubital vein.
Participants were instructed to not engage in physical ac-
tivity beyond their basic daily activities 24 h before the
blood draw. Following the separation of serum, concentra-
tions of cholesterol (TC) and triglycerides (TG) were mea-
sured by an enzymatic procedure (Hitachi 7450 analyzer,
Hitachi, Ltd., Tokyo, Japan). High-density lipoprotein cho-
lesterol (HDLC) was measured using the tungstophosphlic
acid-magnesium chloride precipitation method (Hitachi
7150 analyzer) and low-density lipoprotein cholesterol
(LDLC) was calculated as TCHDLCTG5 (16).
Exercise-training program.The TR group partici-
pated in a 12-wk WEX program, 3 sessionswk
1and 70
min per session. Each session was led by trained fitness
instructors and supervised by the researchers. Training wasperformed on three different days of the week with at least
1 day of rest between sessions. The water level was fixed at
xiphoid or near xiphoid level with an average water tem-
perature of 30C. The daily exercise program consisted of
stretching and warm-up exercise (20 min), endurance-type
exercise (walking and dancing, 30 min), resistance exercise
(10 min), and cool-downrelaxation exercise (10 min). The
warm-up consisted of stretching exercises before entering
the pool followed by slow-pace walking while changing the
rhythm and direction in water. For the endurance-type ac-
tivity, participants walked, danced, and performed a com-
bination of both while in the water. The intensity of aerobic
exercise was prescribed on the basis of the baseline peak
V
O
2, and the HR corresponding to LT was used as an
indicator of the prescribed intensity during exercise. The HR
was monitored continuously for all participants during train-
ing sessions by a HR monitoring device (ECG, Accurex
Plus, Polar Electro, Finland) to ensure that the training
intensity was maintained as prescribed. The resistance ex-
ercises were performed using Finbell water-resistance prod-
ucts (Sanritsu Co., Nagoya, Japan) that included soft cush-
ioned hand bars and leg pads that provided resistance when
moved under the water. Dumbbell- and barbell-type devices
were used to perform upper body resistance exercises (chest
press, biceps curl, lumber rotation) and leg pads were used
to perform lower body exercises (knee extension and flex-
ion, leg extension and flexion, leg press and leg curl, calf
press, leg abduction and adduction) during each exercise
session. Because of the physical characteristics of water, the
resistance increases with the velocity of movement. Thus,
the participants were instructed to move through the full
range of motion for each exercise as rapidly as possible
while performing each repetition. Each exercise was per-
formed for one set of 1015 repetitions. The cool-down
consisted of floor exercises and muscular relaxation.
Statistical analysis.The data are presented by mean
SD. Percent changes from before to after were calculated
from the differences in the scores. Comparisons of means at
baseline between the two groups were performed using a
two-tailed, independentt-test. APvalue, seta priori,of
0.05 was considered statistically significant.
RESULTS
Pretraining data.No significant differences at baseline
were present between the TR group and controls in age,
resting HR, resting systolic blood pressure, and resting
diastolic blood pressure (Table 1). Height was significantly
less in the TR group compared with the controls (Table 1).
TABLE 1. General characteristics of participants at baseline (meanSD).
Exercise Group (TR)
(N15)Control
(N15)
Age (yr) 69.34.5 69.33.3
Height (cm) 149.64.2 154.26.7*
HR rest (bpm) 77.710.9 73.48.5
SBP rest (mm Hg) 129.16.8 131.314.2
DBP rest (mm Hg) 76.77.8 779.9
* Significantly different (P0.05) between groups.
546Official Journal of the American College of Sports Medicine http:www.acsm-msse.org

However, body weight and skin-fold thickness were similar
between groups at baseline (Table 2).
As some of the participants (TR group,N7; controls,
N8) failed to achieve the criteria established for V
O
2maxduring both precycle and postcycle ergometry testing, the
peak value of V
O
2(peak V
O2) was used for analysis. There
were no significant differences at baseline in V
O
2LT or
peak V
O
2between the groups (Fig. 1). The LaatLTand
at peak V
O
2, peak RER, peak exercise systolic blood pres-
sure, and RPE were also similar between groups at baseline.
Training data.All of the participants continued the
WEX training through the full length of the study without
any case of injury. Participants did not suffer any injuries as
a result of the training program. The TR group trained at a
moderate intensity as indicated by weekly averages of train-
ing HR during walking and dancing exercise. Participants
were exercising at 67% of HR
maxwhile walking and 65% of
HR
maxwhile dancing during week 1 and 78% of HRmaxwhile walking and 71% of HRmaxwhile dancing during
week 12. The RPE averaged 11.81.2 during the first
week and 13.51.4 during the final week.
No significant changes were noticed in resting HR, rest-
ing systolic blood pressure, and resting diastolic blood pres-
sure in either group. Skin-fold thickness decreased signifi-
cantly (8%), but arm girth and thigh girth did not changein the TR group (Table 2). No changes in any of these
variables were noticed in the control group. No significant
change in body weight was noticed in either group (Table
2). Total cholesterol (24.3 mgdL
1) and LDLC
FIGURE 1Effects of water-based exercise on cardiorespiratory fit-
ness in older women.
TABLE 2. Effects of water-based exercise on fitness and blood lipid parameters in older women.
Before After
Change
(%)ANOVA
(GroupTime) Mean SD Mean SD
Body weight (kg)
Exercise group 52.2 8.6 51.9 8.6 0.6F(1,28)0.403
Control group 52.7 6.4 52.5 6.4 0.4P0.10
Skin-fold thickness (mm)
Exercise group 40.5 11.1 37.3 10.3 7.9F(1,28)4.516
Control group 47.5 12.5 49.4 12.7 4.0P0.05
Arm girth (cm)
Exercise group 27.7 2.8 28.0 2.9 1.1F(1,28)3.614
Control group 28.4 1.8 28.3 2.0 0.4P0.07
Thigh girth (cm)
Exercise group 45.0 3.7 45.5 4.6 1.1F(1,28)0.654
Control group 46.8 2.8 47.0 2.8 0.4P0.10
Vertical jump (cm)
Exercise group 23.1 4.6 25.2 4.4 9.1F(1,28)10.48
Control group 23.0 4.8 22.3 4.5 3.0P0.05
Side step (steps20 s
1)
Exercise group 23.3 5.2 28.4 4.4 21.9F(1,28)7.823
Control group 22.9 5.2 23.9 5.7 4.4P0.05
FEV
1.0(L)
Exercise group 1.67 0.41 1.78 0.37 6.6F(1,28)7.043
Control group 1.68 0.32 1.58 0.35 6.0P0.05
Trunk extension (cm)
Exercise group 32.6 11.1 36.1 8.0 10.7F(1,28)5.129
Control group 29.7 9.6 29.2 9.9 1.7P0.05
Trunk flexion (cm)
Exercise group 15.4 5.9 16.6 4.7 7.8F(1,28)1.348
Control group 8.3 8.0 8.5 8.3 2.4P0.10
TC (mgdL
1)
Exercise group 219.6 37.9 195.3 35.5 11.1F(1,28)4.426
Control group 227.2 25.0 214.9 21.0 5.4P0.05
HDLC (mgdL
1)
Exercise group 62.3 15.5 62.4 15.6 0.2F(1,28)0.378
Control group 67.4 17.1 68.5 17.6 1.6P0.10
LDLC (mgdL
1)
Exercise group 128.6 39.1 106.7 34.0 17.0F(1,28)9.897
Control group 121.8 2.1 116.1 16.3 4.7P0.05
TG (mgdL
1)
Exercise group 86.1 27.8 78.8 28.6 8.5F(1,28)2.415
Control group 113.9 47.8 90.9 34.6 20.2P0.10
WATER-BASED EXERCISE IN OLDER ADULT WOMEN Medicine & Science in Sports & Exercise
547

(21.9 mgdL1), but not HDLC or TG, were significantly
changed in the TR group following WEX training (Table 2).
The FEV
1.0increased by 7% in the TR group and declined
by 6% in the control group (Table 2).
The vertical jump score increased by 2.1 cm (9%), side-
stepping agility increased by five steps in 20 s (22%), and
trunk extension increased by 3.5 cm (11%) in the TR group
following WEX training, but were not changed in the con-
trol group (Table 2). The WEX increased V
O
2at LT by 20%
(before, 0.7770.214 Lmin1; after, 0.9340.224
Lmin1;F(1,28)49.309,P0.05) and peak V
O2by
12% (before, 1.1780.39 Lmin1; after, 1.3140.341
Lmin1,F(1,28)5.262,P0.05) in the TR group (Fig.
1). There was no significant change in La at peak V
O2(before, 2.30.6 mM; after, 3.01.5 mM) but a signif-
icant change was noticed in La at LT (before, 0.90.3
mM; after, 0.70.2 mM) in the TR group. Peak HR did not
change significantly (before, 153.515.1 bpm; after, 157.5
15.0 bpm) but HR at LT (before, 95.87.7 bpm; after,
113.913.5 bpm) did increase significantly in the TR
group. There were no significant changes in V
O
2at LT or
peak V
O
2(Fig. 1), La at peak V
O2(before, 2.41.1
mM; after, 2.00.7 mM), La at LT (before, 0.90.3
mM; after, 0.90.2 mM), peak HR (before, 14810 bpm;
after, 14416 bpm), and HR at LT (before, 1018 bpm;
after, 1099 bpm) in the control group. No significant
changes were noticed in peak RER (TR group: before, 1.03
0.4; after, 1.040.11; controls: before, 0.980.12;after, 0.940.01), peak exercise systolic blood pressure
(TR group: before, 21822 mm Hg; after, 22727 mm
Hg; controls: before, 21322 mm Hg; after, 21017 mm
Hg), or RPE (TR group: before, 172; after, 172;
controls: before, 162; after, 162) in either group.
In general, muscle strength increased in the TR group
following WEX training. Knee extension strength at hydrau-
lic setting 2 increased by 27% with training and knee flexion
strength measured at this setting increased by 40% in the TR
group. In addition, knee extension and flexion strength were
increased at setting 5 (16% and 22%, respectively) and
setting 8 (8% and 13%, respectively) following training
(Table 3). Chest press strength increased at setting 2 (11%),
whereas chest pull strength increased at setting 5 (7%) and
setting 8 (11%) (Table 4). Lumbar flexion and extension
strength increased at setting 5 (3% and 7%, respectively),
and only lumber extension strength increased (6%) signifi-
cantly at setting 8 (Table 5). Shoulder press and pull
strength increased at setting 5 (5% and 15%, respectively)
and setting 8 (4% and 6%, respectively) (Table 6). None of
the muscular strength variables increased significantly in the
control group.
DISCUSSION
In this study, WEX led to an increase in oxygen uptake at
LT (20%) and at peak (12%). In addition to the improve-
ments in cardiovascular fitness that may be expected with
TABLE 3. Effects of water-based exercise on muscular strength in older women: knee.a
Resistance DialBefore After
Change (%)ANOVA
(GroupTime) Mean SD Mean SD
Extension, Nm
Exercise group 2 5.6 1.1 7.1 2.1 26.8F(1,28)3.704
Control group 2 6.1 1.3 6.7 1.6 9.8P0.09
Exercise group 5 14.6 3.8 17.0 3.6 16.4F(1,28)7.023
Control group 5 15.3 3.7 15.1 3.01.3P0.05
Exercise group 8 34.4 8.0 37.3 7.4 8.4F(1,28)7.564
Control group 8 34.4 5.3 33.7 5.32.0P0.05
Flexion, Nm
Exercise group 2 6.0 2.7 8.4 3.1 40.0F(1,28)12.225
Control group 2 6.8 1.6 6.5 1.84.4P0.05
Exercise group 5 14.4 5.1 17.5 5.9 21.5F(1,28)11.592
Control group 5 15.5 3.7 14.4 3.77.1P0.05
Exercise group 8 26.0 7.8 29.3 8.1 12.7F(1,28)12.780
Control group 8 28.6 4.6 26.7 4.66.6P0.05
aKnee value is mean average between right and left knee extension and flexion.
TABLE 4. Effects of water-based exercise on muscular strength in older women: chest.
Resistance DialBefore After
Change
(%)ANOVA
(GroupTime) Mean SD Mean SD
Press, Nm
Exercise group 2 47.3 10.7 52.3 11.5 10.6F(1,28)5.560
Control group 2 55.5 9.0 51.5 13.97.2P0.05
Exercise group 5 124.8 47.9 133.4 46.8 6.9F(1,28)2.365
Control group 5 133.7 45.0 111.3 23.316.8P0.10
Exercise group 8 216.6 41.4 231.1 40.7 6.7F(1,28)4.077
Control group 8 221.4 46.1 213.9 49.13.4P0.05
Pull, Nm
Exercise group 2 73.7 35.2 73.5 17.20.3F(1,28)0.140
Control group 2 70.9 12.1 66.5 28.06.2P0.10
Exercise group 5 142.6 31.1 153.1 36.5 7.4F(1,28)5.226
Control group 5 151.0 31.5 141.0 33.46.6P0.05
Exercise group 8 224.1 45.2 248.2 53.2 10.8F(1,28)4.651
Control group 8 234.2 45.1 229.3 46.12.1P0.05
548Official Journal of the American College of Sports Medicine http:www.acsm-msse.org

any aerobic training program, the WEX improved several
other health-related components of fitness including muscle
strength and power, flexibility, agility, and subcutaneous
fat. Furthermore, the TR group demonstrated an improve-
ment in pulmonary function (increase in FEV
1.0) and blood
lipids (reductions in TC and LDLC). This study indicates
that WEX leads to the improvement of health and fitness.
Therefore, WEX should be prescribed as part of a well-
rounded exercise program for older women.
Although V
O
2was not measured during WEX, the HR
and RPE were determined during each exercise session. The
mean values for HR and RPE during the aerobic component
of the WEX indicate that the intensity was of light to
moderate intensity. In this study, the baseline HR at LT was
used to prescribe the target HR during WEX and the HR was
monitored continuously as described in the Methods section.
There are some limitations in selecting the intensity of WEX
on the basis of HR, particularly in the case of head-out WEX
in young adults (3,10). However, our previous work indi-
cates that the HR response and RPE at a given V
O
2during
WEX is similar to walking on land in older adults (34).
Cardiorespiratory endurance is defined as the ability to
perform dynamic, moderate- to high-intensity work using a
large muscle mass for an extended period of time (7). The
accepted single best measure of cardiorespiratory fitness is
V
O
2maxin healthy subjects. However, in the present study,
approximately half of the participants failed to reachV
O
2maxas defined by a plateau in O2consumption with a
corresponding increase in workload, RER greater than 1.1,
or predicted maximal HR. Therefore, peak V
O
2was used as
a measure of cardiorespiratory fitness, and this increased by
12% in TR. This result is similar to the increased V
O
2max(10%) observed previously in our laboratory using a similar
progressive testing protocol following 12 wk of land-based
aerobic training in Japanese older adults (33).
Increases in V
O
2at LT (20%) were even greater than
those observed in peak V
O
2following WEX. This is also
similar to results from our previous land-based training
study that indicated an 18% increase in V
O
2at LT (33). The
LT is a term that refers to the V
O
2or exercise intensity
above which the rate of Laproduction exceeds the rate at
which it can be catabolized, thus inhibiting the increase of
La
in the blood (35). The LT is known to be affected by
many factors including oxygen transport, activity of the
oxidative enzymes in mitochondria of skeletal muscle, and
composition of the muscle fibers. Therefore, the increase in
LT observed with WEX in this study may have been asso-
ciated with an increase in aerobic enzyme activity andor an
increase in the proportion of oxidative fibers recruited. The
resulting increase in LT after WEX training may be of great
consequence, as it could allow older adults to engage in
sustained rigorous work for longer periods of time. How-
ever, information regarding LT in older adults is lacking,
and much more research on this topic is required.
TABLE 5. Effects of water-based exercise on muscular strength in older women: low back.
Resistance DialBefore After
Change
(%)ANOVA
(GroupTime) Mean SD Mean SD
Extension, Nm
Exercise group 2 62.3 27.3 61.5 18.81.3F(1,28)0.503
Control group 2 54.9 20.4 50.2 25.48.6P0.10
Exercise group 5 123.6 62.6 131.6 48.2 6.5F(1,28)5.523
Control group 5 130.8 49.2 104.8 46.519.9P0.05
Exercise group 8 216.4 78.1 230.0 51.8 6.3F(1,28)5.222
Control group 8 231.1 57.4 197.9 74.614.4P0.05
Flexion, Nm
Exercise group 2 32.3 12.5 29.3 12.09.3F(1,28)0.055
Control group 2 34.4 11.9 29.5 12.014.2P0.10
Exercise group 5 68.4 26.0 70.5 27.1 3.1F(1,28)6.784
Control group 5 74.6 24.2 59.8 22.919.8P0.05
Exercise group 8 132.8 30.9 127.9 39.43.7F(1,28)2.187
Control group 8 142.6 41.7 117.5 49.917.6P0.10
TABLE 6. Effects of water-based exercise on muscular strength in older women: shoulder.
Resistance DialBefore After
Change
(%)ANOVA
(GroupTime) Mean SD Mean SD
Press, Nm
Exercise group 2 19.3 5.8 17.8 4.67.8F(1,28)0.316
Control group 2 21.7 5.6 20.9 5.43.7P0.10
Exercise group 5 44.6 14.2 46.6 14.2 4.5F(1,28)6.297
Control group 5 54.3 10.2 49.2 12.29.4P0.05
Exercise group 8 88.2 28.1 92.0 25.4 4.3F(1,28)5.526
Control group 8 106.6 22.8 96.7 22.99.3P0.05
Pull, Nm
Exercise group 2 51.3 18.8 56.1 20.4 9.4F(1,28)2.387
Control group 2 55.9 13.6 55.2 16.61.3P0.10
Exercise group 5 104.9 34.4 121.1 34.6 15.4F(1,28)6.191
Control group 5 122.8 28.0 115.5 45.25.9P0.05
Exercise group 8 193.8 43.3 205.5 47.4 6.0F(1,28)7.852
Control group 8 223.8 36.2 208.0 42.97.1P0.05
WATER-BASED EXERCISE IN OLDER ADULT WOMEN Medicine & Science in Sports & Exercise
549

Significant improvements in skin-fold thickness were asso-
ciated with WEX training. Results from our study indicate a
decrease of 7.9% in the sum of these skin folds for the exercise
group and an increase of 4.0% in the control group after 12 wk.
Skin-fold thickness has been previously reported to be reduced
by 7.0% and 17% at the subscapular site and 5.5% and 14.1%
at the triceps site after 7 and 14 wk of endurance training,
respectively (29). Although this method does not estimate body
compositionper se, it is an indicator of subcutaneous adiposity.
The finding that skin-fold thickness decreased, yet arm and
thigh girth did not change, suggests that the TR group may
have gained lean mass. Many studies using weight training
ranging from moderate to high intensity have reported in-
creases of muscle strength and hypertrophy in elderly men and
women (13,15,17). To our knowledge, no report is available
describing changes in muscle mass by WEX in the elderly.
Further study is needed to determine the effects of WEX on
muscle mass, intermuscular and intramuscular fat depots, and
bone density.
In the present study, TC and LDLC improved as a result
of WEX. The TG and HDLC, however, did not change
significantly. This is in agreement with our previous find-
ings from a 12-wk endurance training program using cycle
ergometers in older Japanese adults (33). Several investiga-
tors have reported alterations in lipid profiles including
increases in HDLC (7). Stein et al. (30) described that a
minimal exercise intensity of 75% of the maximum HR was
required to improve HDLC in a group of healthy middle-
aged men. This level of intensity is above that performed
during the present study. However, the effects of exercise
training on serum lipid concentrations are affected not only
by exercise intensity, but also by the duration and type of
exercise, as well as by other factors including food intake
(20,23,24,27,31,33). Although participants were instructed
to not change their dietary habits, no measure of nutritional
intake was performed. Given that dietary intake is an im-
portant factor in determining body composition and blood
lipid concentrations, further research is needed to determine
how nutrition and WEX may interact to affect the blood
lipid profiles of older adults.
Aging is associated with a gradual decrease in muscle
mass, strength, and power (19,27). This contributes to de-
creased mobility, decreased functionality, and increased risk
of falling in older individuals (6,14). Recently, the ACSM
recognized the benefits that can result from adding strength
training to the exercise programs of aerobically active peo-
ple (1,2). In the present study, most muscle strength andpower measures improved significantly as a result of mov-
ing the arms and legs against the resistance of the water.
Back strength was not affected to such a large extent as the
arms and legs. This might be a result of the specific exer-
cises used during training, or that the buoyant force of the
water supports the body and reduces the reliance on postural
muscles usually used while standing on land. Future WEX
training studies should emphasize the use of back muscles in
the exercise movements. Future studies should also give
attention to the effects of WEX training on the performance
of common activities of daily living that allow older adults
to maintain independent lifestyles such as performing
housework, shopping, using public transportation, carrying
groceries, and climbing stairs.
There was no significant improvement in trunk flexion,
possibly because it is difficult to perform trunk flexion
exercises in the water without submerging the head. How-
ever, as a result of WEX training, trunk extension and agility
improved, which could have a positive impact on the per-
formance of activities of daily living as well as in the
avoidance of falls. Lower body strength, flexibility, and
agility have been associated with deficits in balance (in-
creased postural sway) and impairments in gait function
such as slower velocity and decreased stride length (36).
Further study is needed to explore the effect of WEX on
these parameters in older adults.
CONCLUSION
Our results indicate that exercising in water can signifi-
cantly improve cardiorespiratory fitness, muscular strength,
body composition, blood lipids, agility, and flexibility in
older adults. Moreover, it may provide additional benefits
by reducing the incidence of falls and injuries that occur
while performing exercise, or while performing activities of
daily living. Therefore, water-based exercise is a beneficial
mode of exercise for older adults and can be safely used as
part of a well-rounded exercise program.
We acknowledge the participants for their voluntary involvement
in this study. This study was supported by grant 09680119 from the
Japanese Ministry of Education and grant 10150205 from the Japan
Ministry of Health and Welfare.
Address for correspondence: Nobuo Takeshima, Ph.D., Labora-
tory of Exercise Gerontology, Institute of Natural Sciences, Nagoya
City University, 1 Mizuho-cho, Mizuho-ku, Nagoya 467-8502, Ja-
pan; E-mail: nob@nsc.nagoya-cu.ac.jp.
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