Advances in Physical Education
2012. Vol.2, No.4, 139-143
Published Online November 2012 in SciRes (http://www.SciRP.org/journal/ape) http://dx.doi.org/10.4236/ape.2012.24024
The Effects of Knee Joint Pain and Disorders on Knee Extension
Strength and Walking Ability in the Female Elderly
Hiroki Sugiu ra, Shinichi Dem ura
Graduate School of Natural Science & Technology, Kanazawa Unive rs i ty, Kanazawa, Japan
Received August 4th, 2012; revised September 8th, 20 12 ; a cce pte d S ep tember 20th, 2012
This study examines the differences in leg strength and walking ability among groups with different knee
problems. The participants were 328 elderly females (60 - 94 years old; mean age 76.1 years; SD = 6.2)
who were classified into three groups: those without knee pain or a knee disorder, those with knee pain,
and those with a knee disorder. The subjects took knee extension strength and 12 meter maximum effort
walk tests. Knee extension strength was significantly lower in the groups with knee pain and a knee dis-
order than in the group without pain or a knee disorder. Walking speed was significantly slower in the
group with a knee disorder than in the other two groups. In conclusion, the female elderly with knee pain
or a knee disorder are inferior in knee extension strength and walking ability. In addition, the elderly with
a knee disorder are inferior in walking ability to the elderly with knee pain.
Keywords: Knee Joint Pain; Knee Joint Disorder; Knee Extension Strength; Gait; Female Elderly
Introduction
Walking is the most basic movement in daily life (Pratt,
1994). Leg strength, balance and leg joint functions are impor-
tant factors related to walking. These physical functions de-
crease with age, and thus walking ability also decreases with
age. As a result, the frequency of daily life activities is limited
markedly, and there is also a decrease in the ability to perform
activities of daily life (ADL) (Jochanan et al., 2009; Hurley et
al., 1998). In addition, a decrease in walking ability also in-
creases fall occurrences (Mary & Tinetti, 2003), which there-
fore greatly reduces quality of life (Sato et al., 2007; Suzuki et
al., 2002). Hence, it is very important to prevent a decrease in
walking functions in order to maintain independent daily life in
the elderly.
Knee joints have the maximum load capacity of all the leg
joints, and they play a very important role in walking (Kuro-
kawa et al., 2001). Recently, more knee disorders have been
found in the elderly (Peat et al., 2001). Tennant et al. (1995)
reported that 8% of the elderly have them. Leg strength de-
creases with age in the elderly years (Frontera et al., 1991;
Murrary et al., 1985), and the elderly with leg joint disorders
are greatly limited in walking, due to both the knee disorder and
a decrease in leg strength (Zeni & Higginson, 2009; Zoltan et
al., 2006). Hence, the active mass of the elderly with knee dis-
orders decreases markedly, subsequently causing a rapid de-
crease in leg strength (Kirsten, 2009).
Kirsten (2009) reported that subjects with a knee disorder
were inferior in walking speed, stance stability and accelerating
force. Berman et al. (1987) and Andriacchi et al. (1982) re-
ported that the elderly requiring knee arthroplasty are inferior in
walking speed, stance time, step length and cadence, as com-
pared to the general elderly.
On the other hand, there are many older people with subjec-
tive knee pain, even though they do not have a serious knee
disorder (Zoltan et al., 2006; Al-Zaharni & Bakheit, 2002; Peat
et al., 2001). They can be regarded as an auxiliary group to
people with a knee disorder. Alindon et al. (1992) and Urwin et
al. (1998) reported that about 20% of the elderly had knee pain.
Sugiura & Demura (2012) reported that the group with knee
pain was inferior in knee extension strength to the group with-
out knee pain, and the group with pain in both knees was infe-
rior in stride length and step length to the group without knee
pain.
From the above, it is considered that the elderly with a knee
disorder or knee pain are inferior in leg strength and walking
ability to those without a knee disorder or pain. On the other
hand, it is assumed that knee disorder participants with a spe-
cific knee disorder are inferior in leg strength and/or walking
ability to the people with knee pain, who are the reserve group
of subjects with a knee disorder.
The prevalence of knee pain and knee disorders is high in the
female elderly (Oida & Nakamura, 2008; Peat et al., 2001).
This study examines the differences in knee extension strength
and walking ability among female elderly, who are divided into
three groups: those without knee pain or a knee disorder, those
with knee pain, and those with knee disorders.
Methods
Subjects
Subjects consisted of 328 female elderly people (60 - 94
years old; mean age 76.1 years; SD = 6.2), who which classi-
fied into the following three groups: 168 persons without knee
pain or disorder (knee non-pain and disorder group), 116 per-
sons with subjective knee pain (one knee pain group, n = 75;
both knees in pain group, n = 41), and 44 persons with a knee
disorder (one knee disorder group, n = 21; both knees disorder
group, n = 23). Forty persons in the knee pain group and 11
persons in the knee disorder group had right knee pain. The
knee pain and the knee disorder were grouped by Japanese

H. SUGIURA, S. DEMURA
edition knee function scale (Hashimoto et al., 2003) that con-
formed to made WOMAC (Bellamy et al., 1988), and the
cut-off point was set at 210 points (Oida & Nakamura, 2008).
In addition, the elderly with knee disorders were largely divided
into persons who can achieve activities of daily living (ADL)
independently and persons who cannot due to disorders. The
participants regularly visit a hospital for treatment of the knee
disorders, but could perform ADL independently. If the knee
disorder elderly in this study are inferior in walking ability to
the other two groups, it is also assumed that those with a knee
disorder and who cannot perform ADL independently are infe-
rior to them. Table 1 shows the basic statistics of age, height,
and body weight according to each group.
All subjects participated in health classes or social educa-
tional activities hosted by municipal governments, and they
engaged in social activities at least once per week or on alter-
nate weeks. Before the measurements, the purpose and proce-
dure of this study were explained to all of the subjects in de-
tail and informed consent was obtained. The present experi-
mental protocol was approved in advance by the ethics com-
mittee (Kanazawa University Health & Science Ethics commit-
tee).
Leg Strength
To evaluate leg strength, knee extension strength was se-
lected since it is strongly affected by knee pain or disorder (Su-
giura & Demura, 2012; Astephen et al., 2008). During meas-
urement of isometric knee extension strength, the subjects were
seated upright in a rigid chair with the knee flexed at a 90° an-
gle with the lower legs strapped by a pad just above the ankle,
attached by a backward rigid bar to a tension meter attachment
(T.K.K.1269f; Takei Scientific Instruments Co. Ltd., Japan). In
addition, the subjects folded their arms across their chest. A
tester held the pad in place so it would not move, and then
asked the subjects to extend the knee as far as possible and to
maintain it for 3 seconds. Leg strength was measured twice and
the sum of the mean of right and left values was used as a pa-
rameter.
Walking Ability
Gait properties were measured with a gait analysis system
(Walk Way MG-1000, Anima, Japan). The MG-1000 with plate
sensors determines time, dimensions, and the distance of the
foot when the foot touches the sheet surface, and it can measure
grounding/non-grounding on the bearing surface as an on/off
signal. Data were recorded into a personal computer at 100 Hz.
The posture and movement during the measurement were ex-
plained to the subjects before the measurement. The walkway
was 12 meters in length. The subjects walked straight for 12
meters as fast as possible. Data from the middle 5 meter portion,
excluding the first 3 meters and the final 4 meters, were used
for analysis (Figure 1). Walking speed, which is the walking
distance per second, was selected as the indicator of walking
ability.
Statistical Analysis
The intra-class correlation coefficient (ICC) was calculated
to examine the test-retest reliability of knee extension strength.
body weight as a covariate. A Scheffe’s test was used for a
0m 3m7.8m12m
Walkway
4.8m
goalstart 1m
Figure 1.
Setting of WalkWay MG-1000.
Each parameter was examined by ANCOVA with multiple
comparison test if ANCOVA showed a significant difference.
The significance level in this study was set at p < 0.05.
Results
Table 1 shows the basic statistics of age, height and body
weight in the knee non-pain and disorder (G1), one knee pain
(G2), both knees pain (G3), one knee disorder (G4) and both
knees disorder (G5) groups, and the test results among their
means. The result of one-way ANOVA showed a significant
difference only in weight. A linear comparison test of the knee
non-pain and disorder (G1), knee pain (G2 + G3) and disorder
(G4 + G5) groups showed that the knee disorder group is sig-
nificantly heavier than the knee non-pain and disorder group.
Additionally, the body weight between the one knee and the
both knees pain groups, and between the one knee and the both
knees disorder groups showed an insignificant difference.
The ICC of the knee extension strength was very high (right:
0.93; left: 0.92; both: 0.90). Table 2 shows the basic statistics
and test results of knee extension strength in the above five
groups. The result of ANCOVA showed a significant difference.
A linear comparison test showed that the knee pain and knee
disorder groups are significantly inferior in knee extension
strength to the group without knee pain or disorder. Addition-
ally, the knee extension strength between the one knee and the
both knees pain groups, and between the one knee and the both
knees disorder groups showed an insignificant difference.
Table 3 shows basic statistics and test results of walking
speed in the above five groups. The result of ANCOVA showed
a significant difference. A linear comparison test showed that
the knee disorder group is significantly inferior in walking
speed to the knee non-pain and disorder and the knee pain
groups. Additionally, the one knee disorder and the both knees
disorder groups are significantly inferior in walking speed to
the knee non-pain and disorder group, but a significant differ-
ence was not found between the one knee and both knees pain
groups and between the one knee and both knees disorder
groups.
Table 4 shows basic statistics and test results from means of
the above 5 groups for gait parameters. The result of ANCOVA
showed a significant difference in stance time, stride length,
step length, step width, swing speed and cadence. In a linear
comparison test, significant differences were found in the
stance time, step width, swing speed and cadence between the
knee disorder group and both the knee non-pain and disorder
and the knee pain groups. Stride length and step length are sig-
nificantly shorter in the groups with knee pain and disorder
than in the group without knee pain or disorder. Overall, gait
parameters showed significant differences between the one knee
disorder and the both knees disorder group, as well as the
Copyright © 2012 SciRe s .
140

H. SUGIURA, S. DEMURA
Copyright © 2012 SciRe s . 141
Table 1.
The mean difference am ong groups for age, height and body weight.
Knee non-pain
and disorder
(G1: n = 168)
One knee pain
(G2: n = 75) Both knees pain (G3: n = 41) One knee disorder (G4: n = 21) Both knees disorder (G5: n = 23) ANOVA Scheff’s post-hoc
M SD max min M SD max min M SD max min MSD max min MSD max min F p G1, (G2 + G3),
(G4 + G5)
Age
(yr) 74.3 6.8 87 62 76.9 5.9 94 66 76.5 4.7866876.85.2876976.95.685 65 2.25 0.07 -
Height
(cm) 148.1 6.1 164.5 131.6 147.3 6.0 161.4 132.5 147.6 5.6158.8138.4148.85.0156.0138.0146.94.1157.6 142.0 0.37 0.83 -
Weight
(kg) 48.27 7.25 68.7 34.2 49.22 8.41 70.9 32.5 52.41 5.3365.443.554.807.2871.039.052.516.7068.8 43.0 4.11 0.00* G1 < (G4 + G5)
Note: *p < 0.05.
Table 2.
Difference in knee extension str ength among groups.
Knee non-pain
and disorder
(G1: n = 168)
One knee pain
(G2: n = 75) Both knees pain (G3: n = 41) One knee disorder (G4: n = 21) Both knees disorder (G5: n = 23) ANCOVA Scheff’s post-hoc
M SD max min M SD max min M SDmax min MSD max minMSD max min F p G1, (G2 + G3),
(G4 + G5)
Knee
extension
strength
(kg)
14.85 3.97 26.90 7.52 12.69 3.78 22.47 4. 06 12. 45 3.5816.935.9111.183.2017.345.8810.344.5118.25 3.34 9.01 0.00* (G2 + G3),
(G4 + G5) < G 1
Note: *p < 0.05.
Table 3.
Difference in walking speed among groups.
Knee non-pain
and disorder
(G1: n = 168)
One knee pain
(G2: n = 75) Both knees pain (G3: n = 41) One knee disorder (G4: n = 21) Both knees disorder (G5: n = 23) ANCOVA Scheff’s post-hoc
M SD max min MSD max min MSD max min MSD max min MSD max min F p G1, (G2 + G3),
(G4 + G5)
Walking
speed
(cm/s) 177. 7 28.0 240.5 110.8 162. 224.6 236.1 103.7 164. 528.6221. 0106.4142.331.6207.080.1134.131.4 190.6 69.6 9.35 0.00*(G4 +
G5) < G1,
(G2 + G3)
Note: *p < 0.05.
knee non-pain and disorder group. How- ever, significant dif-
ferences were not found between the one knee and both knees
pain groups, and between the one knee and both knees disorder
groups.
Discussion
The knee disorder group had a higher body weight than the
knee non-pain and disorder group. Yoshimura et al. (2004) and
Oliveria et al. (1999) reported that a knee disorder contributes
to a burden increase to knee joints due to a weight increase. In
older age, because leg strength decreases markedly with age
(Frontera et al., 1991; Murrary et al., 1985), the durability of
knee joints is considered to also decrease with age. Sugiura &
Demura (2012) reported that being overweight can contribute to
knee pain in old age. It is believed that active mass decreases
due to knee pain, thus increasing body weight, and because of
the extra burden on knee joints, knee pain may worsen into a
disorder. From the present results, it is concluded that the
heavier body weight of the knee disorder people may be largely
attributed to a limited active mass due to the disorder.
The knee pain and knee disorder groups were inferior in knee
extension strength to the group without knee pain or a disorder,
but an insignificant difference was found between the knee pain
and knee disorder groups. In short, although it was hypothe-
sized that the knee disorder group is inferior in knee extension
strength to the knee pain group, this hypothesis was rejected. It
now thought that the knee disorder subjects in this study could
walk independently (see Subjects in Method); therefore, they
could exert leg strength by enduring pain. The elderly who
cannot walk independently could find it difficult to exert leg
strength maximally, and their leg strength may be inferior to
that of the knee pain people. In any case, it was found that the
participants with knee pain and disorders are inferior in knee
extension strength. On the other hand, the knee extension
strength showed an insignifican difference between the one t

H. SUGIURA, S. DEMURA
Table 4.
Difference in gait parameters among groups.
Knee non-pain
and disorder
(G1: n = 168)
One knee pain
(G2: n = 75) Both knees pain (G3: n = 41) O ne knee disorde r (G4: n = 21) Both knees disorder (G5: n = 23) ANCOVA Scheff’s post-hoc
M SD max min M SD max min MSDmax min MSD max min MSD max min F p G1,
(G2 + G3),
(G4 + G5)
Stance
time (s) 0.43 0.06 0.58 0.30 0.450.06 0.63 0.35 0.430.060.580.320.510.090.720.360.510.060.65 0.42 7.34 0.00* G1, (G2 +
G3) <
(G4 + G5)
Swing
time (s) 0.34 0.03 0.43 0.23 0.340.03 0.42 0.27 0.320.030.380.260.350.030.410.280.350.030.41 0.29 2.35 0.07 -
Stride
length
(cm) 133.3 16.3 172.5 86.5 125.514.9 156.8 86.8 120.817.1153.383.7118.815.5146.176.4113. 220.7151.1 58.4 6.39 0.00* (G2 + G3),
(G4 + G5) <
G1
Step
length
(cm) 66.32 8.06 85.67 42.70 62.347.45 78.42 43.00 60.228.6076.1741.5258.877.4672.6338.8056.3010.3675.29 29.32 6.44 0.00* (G2 + G3),
(G4 + G5) <
G1
Step
width (cm) 7.16 2.42 13.13 1. 00 7.022.02 11.64 3.50 7.762.3212.844.759.153.5815. 503.388.872.6813.75 2.84 3.55 0.01* G1, (G2 +
G3) <
(G4 + G5)
Swing
speed
(cm/s) 399.5 48.8 508.3 254.7 376. 849.2 522.5 256.8 377.655.4478.9265.7343.560.5475.1221.7325.664. 6439. 1 202.5 7.48 0.00* (G4 + G5) <
G1, (G2 + G3)
Cadence
(steps/min) 161.1 18.3 218.2 123.9 156. 316.8 191.5 114.4 162.518.5210.0125.4144.220.8185.6110.1142.913. 6172. 8 115.4 5.09 0.00* (G4 + G 5) < G1, (G2 + G3)
Note: Stance time is the duration that th e body is supported b y one foot, that is, the phase in which one foot contacts the flo or. Swing time is the duration th at one foot
swings, that is , whi le one foot is rai sed off the floor. St rid e length is th e length of t wo cons ecut iv e steps . St ep l ength is the distance between anterior-posterior patterns (one
step length ). St ep widt h is the dist ance between bot h feet . Swing speed is the speed when subjects extend a leg forward in the stride length. Cadence is the number of steps
per minute . *p < 0.05.
knee and the both knees pain groups, and between the one knee
and the both knees disorder groups. Since they can walk inde-
pendently, it is inferred that they can also exert leg strength
while enduring pain.
Walking speed is generally used as an index of the walking
ability (Astephen et al., 2008; Nakazawa, 2010). Suzuki (2009)
reported that 31.1% of the elderly with walking speeds less than
120 cm/s have geriatric syndrome (falls, urinary incontinence,
malnutrition, depression). Thus, it is important to prevent a
decrease in walking speed to continue living independently
(Nakazawa, 2010). The present results show that walking speed
of the knee disorder group is slower than that of the other two
groups. Astephen et al. (2008) reported a similar result. It is
inferred that the knee disorder people are inferior in walking
ability. As stated before, a difference in the knee extension
strength between the knee pain group and the knee disorder
group was not found in this study. Since knee extension
strength was measured in a seated position, body weight did not
burden the knee joint. In contrast, during walking, the full
weight is a burden on the knee joints. Other physical fitness
factors (e.g., balance ability) also affect walking. Therefore,
although there was no significant difference in knee extension
strength between both groups, the knee disorder group is con-
cluded to have been slower than the knee pain group in walking
speed, due to the larger body weight burden on the knee.
Sugiura & Demura (2012) reported that there was no signifi-
cant difference in gait between the one knee pain people and
the both knees pain people. In addition to the above, it was also
confirmed in this study that there is no significant difference in
the gait of the one knee disorder people and both knees disorder
people. The knee disorder people in this study do not have pa-
ralysis and/or rheumatism in the lower limbs (Nakazawa, 2010;
Maruyama, 2003), which make stable gait difficult, and they
could walk independently (see Subjects in Method). The elderly
who can walk independently can exert leg strength to some
extent, regardless of whether one or both knees have pain or a
disorder. Hence, their gait showed little difference.
If walking speed is inferior, the gait is also assumed to be
different. The results presented here suggest that stance time,
step width, swing speed and cadence of knee disorder people
are different from the knee pain people and people without knee
pain or a disorder. In addition, the stride and step length of the
knee pain and disorder people were shorter. Kirsten (2009)
reported that because elderly with knee disorders bend their
knee joints during the swing phase, their step length is shorter
than that of the elderly without knee pain or disorder. Morrison
(1970) reported that during the in stance phase of a maximum
velocity walk, a load equaling quadruple the body weight im-
poses on the knee joint. Hence, it is concluded that a large load
burdens the knee joints during the in stance phase for individu-
als with knee pain or disorders. On the other hand, Demura et al.
(2011) and Patla (1997) reported that the gait change of the
elderly is a kind of strategy to maintain stability during walking.
In short, a decrease in stride and step length may be a walk
strategy to reduce the burden on the knee joints for elderly with
knee pain and disorders. As already stated, more gait parame-
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142

H. SUGIURA, S. DEMURA
ters (stance time, step width, swing speed and cadence) showed
significant differences between the knee disorder group and the
knee pain group. It is inferred that the knee disorder individuals
establish a strategy to maintain walking stability, rather than
trying to walk quickly.
It is necessary to further examine ability to achieve activities
of daily living other than walking in the female elderly with
knee pain and disorder.
Conclusion
In conclusion, the female elderly with knee pain and/or dis-
orders are inferior in knee extension strength and walk ability to
the elderly without knee pain or disorder. In addition, the fe-
male elderly with knee disorders are inferior in walking ability
to the elderly with knee pain.
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