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THE EFFECT OF HIGH RESISTANCE WEIGHT TRAINING ON REPORTED PAIN IN
OLDER ADULTS
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Western Washington University, Bellingham, WA, USA.
| Received |
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21 May 2007 |
| Accepted |
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23
July 2007 |
| Published |
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01
December 2007 |
©
Journal of Sports Science and Medicine (2007) 6, 455- 460
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| ABSTRACT |
| The present study examined the effect of a progressive, whole-
body, high resistance training program on reported pain in older adults.
Ninety-eight participants (60 - 83 years) completed the McGill Pain
Questionnaire prior to and after an eight week training period. Seventy-nine
of the participants completed a progressive, high resistance training
program of 11 different exercises on three days a week. At the end
of eight weeks, the training group achieved significant strength gains
ranging from 62% -119% (p < 0.005). Pain measures for the training
and control groups were compared using an analysis of covariance on
post-test pain measures after an adjustment by pre-test scores. (p
< 0.05). The training group reported less perceived pain than the
control group in four pain measures (overall pain intensity, sensory
dimension, miscellaneous pain measures, number of pain descriptors
selected). There were no differences reported for the affective or
evaluative dimensions of perceived pain, the number of painful areas,
or the present pain. Results suggest that eight weeks of progressive,
whole-body weight training has a positive impact on perception of
pain in older adults.
KEY
WORDS: McGill
Pain Questionnaire, joint pain, strength.
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| INTRODUCTION |
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With increasing age, a complex process of physiologic changes
occur (American College of Sports Medicine [ACSM], 1998).
Chronic musculoskeletal conditions, such as osteoarthritis (OA),
fractures associated with osteoporosis, and low back disorders become
more prevalent; and these chronic conditions cause a considerable
amount of pain in older adults (Roche and Forman, 1994;
Vuori, 2001).
Chronic pain among the elderly represents a major public health
concern (Brattberg et al., 1997;
Crook et al., 1984;
Von Korff et al., 1988).
An estimated 87% of community dwelling older adults suffer from
pain, while among nursing home residents, the prevalence is as high
as 80% (Herr and Garand, 2001).
In older adults living in rural Iowa, as high as 86% reported pain
of some type with 59% reporting multiple pain complaints (Mobily
et al., 1994).
In the elderly, chronic pain is mainly a result of degenerative
joint and spine disease coupled with leg and foot disorders (Helme
and Gibson, 2001).
Chronic pain results in decreased movement and loss of strength
(Marcus, 2000)
and limits the ability to engage in the activities of daily living
(Rucker et al., 1996).
The risk of falling is higher among those with chronic pain (Marcus,
2000)
and falls are one of the leading causes of injury, disability, and
premature death in the elderly. In addition to the physical risks,
older adults with chronic pain experience depression, impaired cognitive
function, sleep disturbance, diminished socialization, and loss
of independence (Herr and Garand, 2001;
Marcus, 2000;
Roche and Forman, 1994;
Vuori, 2001).
Furthermore, they are five times more likely to use health care
services than elderly without chronic pain (Marcus, 2000)
and incur higher health care costs (Herr and Garand, 2001;
Woolf and Pfleger, 2003).
It is therefore understandable that chronic pain plays a major role
in a diminished quality of life among the elderly (Crook et al.,
1984).
One major cause of chronic pain in the elderly is osteoarthritis
(OA), a degenerative joint disease that affects 50% of Americans
65 years of age and older (AGS, 2001)
and 80% of Americans 75 years of age and older (McCarberg and Herr,
2001).
OA is a commonly associated with chronic joint pain, loss of range
of motion, and muscle weakness. (Kovar et al., 1992).
Sarcopenia, a loss of muscle mass and strength that occurs with
aging, may contribute to the disability and pain of patients with
OA (Hurley and Roth, 2000;
Suomi and Collier, 2003).
Strength training is thought to reduce functional instability and
pain in older osteoarthritic patients by preventing sarcopenia and
by improving the strength and function of the surrounding connective
tissue (AGS, 2001;
Hughes et al., 2004;
Hurley and Roth, 2000).
Several studies support that strength training can significantly
reduce pain in elderly patients with OA (Baker et al., 2001;
Hughes et al., 2004;
O'Reilly et al., 1999; Rogind et al., 1998; Shilke et al., 1996;
Suomi and Collier, 2003). Combination exercise programs (aerobic and strength)
(Focht, 2006) as well as long-term exercise programs (Wilder et al.,
2006) are also seen as effective for improvement of knee pain
in individuals with osteoarthritis. A long term pattern of aerobic
exercise has been shown to reduce reported pain values in older
adults by as much as 25% (Bruce et al., 2005) and exercise in general has been shown to be an effective
pain management strategy (Kemp et al., 2005).
Other medical conditions such as rheumatoid arthritis (RA), back
pain, and osteoporosis have also been shown to benefit from exercise
programs. In a study of RA patients, a 12-week progressive high-resistance
training program did not change the number of painful or swollen
joints in participants; however, a significant reduction (21%) occurred
in participants' self-reported pain score (Rall et al., 1996). A 10-week exercise program of balance, strength, flexibility
and relaxation resulted in a significant reduction in reported pain
by participants with osteoporosis (Malmros et al., 1998). Similarly, a 12-month program of aerobic, flexibility,
and strengthening exercises focusing primarily on the upper limbs,
shoulder girdle, the abdomen, and the back of osteopenic women lowered
back pain intensity (Bravo et al., 1996). Physical training that reconditions back muscles has
also been shown to be effective therapy for low back pain (Johannsen
et al., 1995; Mannion et al., 1999).
Clinical investigators have long recognized that pain has many qualities
and dimensions (Melzack, 1983). In recent decades pain has come to be regarded as a
multidimensional construct: sensory qualities of pain, affective
reactions to pain, and pain intensity (Holroyd et al., 1996). The McGill Pain Questionnaire (MPQ), developed in 1975
by Melzack and Torgerson, is a well-known and frequently used multidimensional
instrument for measuring the quality and intensity of pain in English-speaking
countries. It quantifies three dimensions of the pain experience:
sensory, affective, and evaluative (Chapman et al., 1985). The purpose of this study was to examine the effect
of a whole-body progressive strength training program on selected
pain parameters of older adults. Several indices of the MPQ were
administered before and after an eight-week strength training program
to measure participants' self-reported pain. The university Human
Subjects Review Board approved this study.
| METHOD |
|
Participants
Participants for this study were recruited through advertisements
via the local hospital network, community senior centers,
and retirement homes within the county. There were 97 volunteer
participants, 57 women (59%) and 40 men (41%) assigned to
a control (n =19) and treatment group (n = 79). The older
adults ranged in age from 60-83 (Treatment M = 71.5 ± 6.5yrs.;
Control M = 70.0 ± 6.5 yrs). The height of participants ranged
from 102 to 184 cm (Treatment M = 1.66 ± 0.11 m; Control M
= 1.68 ± 0.08 m) and in weight from 49 to 126 kg (Treatment
M = 76.0 ± 14.8 kg; Control M = 73.1 ± 17.1 kg). Participants
received medical clearance from their physicians before participation
in the study. They were excluded if they suffered from any
serious medical conditions, including uncontrolled heart or
respiratory problems and dementia.
Instrument
The MPQ is a reliable and valid measure of the quality and
quantity of pain that is frequently used in pain-related research
(Chapman et al., 1985; Love et al., 1989; Melzack, 1975). Recognizing that pain is a multidimensional parameter,
the MPQ evaluates pain affect, sensory qualities of pain,
pain intensity as well as other subjective dimensions. This
allows for a quantification of distinct components of the
pain experience. The MPQ provides an estimate of overall pain
intensity: the Pain-Rating Index Total (PRIT). The PRIT consists
of a set of 78 verbal descriptors listed on one page in 20
subclasses of 2 to 6 words each. Each list is arranged in
a continuum from low to high intensity. The overall PRIT score
is obtained by summing all of the descriptors selected. Scores
range from 0 to 78, with 78 being the most intense. A higher
score on the PRIT denotes more pain. Sub dimensions of the
PRIT include measures of the PRI-sensory [0-42], the PRI-affective
[0-14], the PRI-evaluative [0-5], and the PRI-miscellaneous
[0-17] (Wilkie et al., 1990). Each one of these sub dimensions measures a unique component
of self-reported pain. The PRI-affective dimension evaluates
the emotional response to pain such as considering the pain
to be tiring or sickening and is reflective of the perceived
disruption engendered by the pain experience. The PRI-sensory
is a measure of pain sensation and is reflective of a sensory-discriminative
psychological dimension. The PRI-evaluative is representative
of the cognitive response to pain and whether pain is perceived
to be bearable or irritable. A final PRI-miscellaneous dimension
includes four clusters of words that are descriptive of a
variety of pain qualities including words such as radiating,
cool, agonizing, numb, nagging, spreading, piercing and dreadful.
Another variable is the total number of words chosen (NWC)
on the MPQ which ranges from 0-20. Present Pain Intensity
(PPI) is a variable on the MPQ that is the number-word combination
chosen as the indicator of overall pain intensity. The levels
of the PPI scale include none, mild, discomforting, distressing,
horrible, and excruciating (range 0-5) (Escalante et al.,
1995). PPI is a measure of how much a person hurts and is an
estimation of the magnitude of the pain. The final component
of MPQ, the number of painful areas (NPA), consists of anterior
and posterior line drawings of the body on which participants
indicate the spatial distribution of their pain. Participants
mark the location of their pain on the NPA by using the letter
"E" for external pain, "I" for internal
pain, or "EI" if their pain is both internal and
external (Escalante et al., 1995). To score the NPA, a transparent plastic template containing
the human figure divided into 36 numbered regions is overlaid
on the marked pain maps. The number of painful areas (NPA)
affected can be recorded as the sum of individual body areas
affected with pain (Escalante et al., 1995).
Measurement
technique and procedures
Upon arrival at the pre-test, participants read and signed
written informed consent. To assure completion of the MPQ,
research assistants administered individual assessments by
providing verbal information on the selections. Participants
manually completed the written form of the MPQ. All subjects
in the training group were required to attend three resistance
training sessions per week for eight weeks. All subjects completed
the study. At the end of the eight weeks, the MPQ was re-administered
to both the control and the training groups.
Participants trained in groups of 2 to 4 people. At least
one trainer was present for every four participants. The training
sessions began with 5 to 10 minute warm-up and stretching
exercises for the legs, trunk, and arms, followed by 11 different
resistance exercises on Cybex (VR2) equipment: seated leg
press, chest press, lateral row, biceps curl, triceps press,
hip flexion, hip extension, hip abduction, hip adduction,
plantar flexion, and dorsiflexion.
To
gain familiarity with the equipment, practice proper technique,
and avoid injury, participants completed one set of 15-20
repetitions with light weight (4.5 to 13.5 kg) during the
first week of training. At the end of the first week, trainers
assisted participants in determining a one-repetition maximum
on each of the resistance exercises. Maximal capacity was
determined using a predicted one-repetition maximum (Pred-1RM)
utilizing the equation developed by Brzycki, 1993: Pred-1RM = weight lifted / 1.0278 - (0.0278 * number
of repetitions). Participants were instructed to select a
weight they could successfully lift 7 to 10 times without
fatiguing. The validity of using this prediction equation
with older adults has been previously established (Knutzen
et al., 1999). Weekly training weights were based on a percentage of
the predicted 1RM beginning with 50% of the Pred-1RM in the
second week of training, and progressively increasing the
intensity until it reached 80% in the fifth week, which was
held at 80% for the remainder of the eight weeks. The Pred-1RM
was reassessed every two weeks. Participants performed 1 to
3 sets of 7 to 10 repetitions for each of the 11 exercises.
Data
analysis
Overall pain intensity was assessed using the MPQ. Analysis
of covariance (ANCOVA) was used to analyze the post test group
differences in reported pain when adjusted for by pretest
self-reported pain (SPSS software-version 13.0). The dependent
variables measured included pain rating index total (PRIT),
pain rating index sensory (PRIS), pain rating index affective
(PRIA), pain rating index evaluative (PRIE), pain rating index
miscellaneous (PRIM), number of words chosen (NWC), present
pain intensity (PPI), and number of painful areas (NPA). A
paired samples t-test was applied to analyze the differences
between pre-and post-training strength measures for the training
group. A Bonferroni adjustment was made to
control for the experiment-wise alpha for the strength measurements
and the significance level was set at p 0.005.
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| RESULTS |
|
The results of the high resistance weight training program are
presented in Table 1.
To assess the size of the training effect, Cohen's d (Cohen,
1988) was calculated with .20, .50, and .80 scores representing
small, medium and large effects, respectively. The high resistance
training intervention demonstrated significant strength improvement
for all of the exercises (p < 0.005) with predominantly
large effect sizes. The greatest improvements in strength
were seen in exercises involving the hip and ankle joints
(> 100%) while the lowest level of strength gain was seen
in the shoulder and elbow joint exercises. None of the participants
experienced any injuries or reported any muscle soreness associated
with the training.
Analysis of covariance revealed significant differences between
the control and training groups in self-reported pain measures
when adjusted for by pretest pain values (Table
2). The training group reported less perceived pain in
four of the eight pain measures, including overall intensity
of the perceive pain (PRIT), sensory aspects of pain (PRIS),
assessment of various pain qualities (PRIM), and the number
of words chosen to qualitatively assess pain (NWC). The number
of painful areas (NPA), the present pain intensity (PPI),
the affective aspects of pain qualities (PRIA) and the cognitive
perceptions of pain qualities (PRIE) did not differ between
the two groups.
|
| DISCUSSION |
|
The present study sought to evaluate the effect of an eight
week progressive whole-body strength training program on pain
qualities as self-reported by older adults. Improved strength
in the training group was associated with lower pain values
as compared to the controls in four MPQ measures. Of all variables
measured, PRIT may be the most significant because it includes
all dimensions of pain and gives the greatest indication of
overall perceived pain (Kim et al., 1995). The lower PRIT in the training group suggests that progressive
resistance training of all major muscle groups, when performed
three times per week for eight weeks, had a positive impact
on perception of overall pain. In a meta-analysis of 51 studies
who administered the MPQ, Wilkie et al., 1990 report PRIT values in the range of 5.4 to 44.4 with highest
values recorded by individuals with low back pain. Our values
averaged 3.6, with a range of 2 to 22, indicating similar
levels of perceived pain compared to previous studies. Consistent
with the results of the present study, Chok et al., 1999 reported a beneficial effect of an endurance training
program that reduced the PRIT score from 12.8 to 4.5 over
a 6 week period. The overall perceived pain level in the present
study was reduced by 50% after strength training.
The PRI-sensory subclass measures the sensory experience of
pain in terms of temporal, spatial, pressure, and thermal
properties. This dimension ranges from 3.6 to 26.0 in fifty
one studies (Wilkie et al., 1990) with subjects with low back or labor pain reporting the
highest pain intensity in terms of the sensory experience
and dental pain reporting the lowest PRI-sensory scores. Subjects'
pain perception from a sensory perspective was reduced in
individuals with low back pain after a 6 week exercise program
(pre = 7.1; post = 2.14) (Chok et al., 1999). This was also confirmed in the present study, where
the sensory qualities of pain were reported as being more
favorable in the training group. The self-reported sensory
aspects of pain were reduced by 49% after high resistance
weight training.
The training group also reported more favorable pain measures
for the miscellaneous pain dimension (PRI-misc). A variety
of pain qualities are represented in this category, including
words such as cool, nagging, spreading, piercing and dreadful.
PRI-misc scores ranged from 0 to 9.7 across fifty one studies
using the MPQ (Wilkie, 1990) with highest scores in subjects in an acute post-operation
setting. The results of the present study confirm the role
of strength gain on the individual report of miscellaneous
pain measures. The training group utilized fewer words to
describe their pain and overall, the number of words chosen
in both groups was lower that seen in other studies (Wilkie
et al., 1990).
The affective (PRI-affective) dimensions of pain and the evaluative
(PRI-evaluative) dimensions of pain were not significantly
different between the training and control groups. The scores
in the present study were lower than the range of scores presented
in other studies (Wilkie et al., 1990). The affective qualities of pain are represented by tension
and fear and measure emotional and psychological reactions
to pain. The evaluative qualities of pain are represented
by a cognitive, subjective interpretation of pain. The characteristics
of both the training and the control groups indicated they
did not report many pain qualities that were affective or
evaluative. It also may be that even if physical symptoms
of pain are diminished in the training group, psychological
and emotional aspects may not change and participants may
continue to harbor a fear of pain. Additionally, the pain
intensity and the number of painful areas did not significantly
vary between the training and control groups and this is most
likely reflective of ongoing medical conditions which generate
what is perceive to be a similar level of pain intensity (mild)
and is generally located in the same areas (approximately
two areas).
The findings of this study are consistent with similar studies
that have evaluated the effect of exercise on pain in older
adults. Mannion et al. (1999) found chronic back pain was reduced after a three-month
period of strength training. Baker et al., 2001 observed that strength training substantially reduced
pain and improved physical function and quality of life in
patients with knee OA. Schilke and colleagues (1996)
found a significant decrease in pain and an increase in mobility
among those with knee OA. Furthermore, Hughes and colleagues
(2004)
and Suomi and Collier, 2003 found significant
decreases in pain ratings among participants after eight weeks
of exercise training.
We note several limitations of this study. First, the MPQ
is a self-report instrument of pain and therefore subject
to participant's perception. Second, we did not measure whether
participants were involved in other physical activities beyond
the program that may have affected their pain perception,
however, the inclusion of a small control group also fell
under this same limitation and we saw no change in their pain
perception. Last, improved social interaction through the
work-out group and individual instruction and support may
have had a positive effect on overall well being, therefore
reducing perception of pain.
We also note several strengths of our study. First, the evaluation
of the effects of a high resistance weight training program
on self-reported pain parameters has not been specifically
evaluated as it relates to general overall pain. There have
been reported effects of subject strength on pain in specific
joints and for patients with osteoarthritis. Second, we used
a multi-dimensional measurement of pain perception which enhanced
our understanding of pain qualities for an older population.
The MPQ has also been shown to be an effective tool to measure
changes in subjective pain and provides multiple perspectives
of the pain experience not evaluated in other studies. Lastly,
we included whole-body resistance training, which went beyond
the emphasis suggested by Singh (2002): to train muscles of
the lower body to particularly influence mobility and independence,
both of which are negatively affected by chronic pain.
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| CONCLUSION |
There is a growing national initiative to increase physical activity
among older adults. Likewise, there is a need to identify the most
efficient and effective strength training recommendations for older
adults (Seguin and Nelson, 2003).
As it stands, the American College of Sports Medicine recommends two
to three days per week of strength training (ACSM, 1998).
Benefits of strength training include increased muscle and bone mass,
muscle strength, balance, flexibility, self-confidence and self-esteem.
Strength training also reduces many of the symptoms of chronic diseases,
and when combined with balance training, falls. Due to the affect
of pain on people's willingness to participate in any physical activity,
the importance of reducing pain or pain perception among older adults
should not be underestimated.
Our study supports that participants in an eight-week progressive,
whole -body high resistance training program reported reduced pain
qualities as compared to an untrained group of controls. Whether or
not reduced pain perception would occur with a low intensity training
regimen is a question for further research. All resistance work should
be performed at sufficient intensity, however, to confer the many
benefits associated with strength training. With this improved capacity,
older adults can expect to live more productive, active, and independent
lives. |
| KEY
POINTS |
-
Improved strength in older adults had a positive effect on the
perception of pain.
- The
number of painful areas identified and self-reported pain qualities
were diminished following high resistance weight training.
- The
McGill Pain Questionnaire was an effective tool for measuring
changes in pain perception as a result of training.
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| AUTHORS
BIOGRAPHY |
Kathleen KNUTZEN
Employment: Professor, Department of Physical Education,
Health, and Recreation, Western Washington University.
Degree: PhD.
Research interests: Biomechanics, older adult function.
E-mail: Kathy.Knutzen@wwu.edu
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Beth
PENDERGRAST
Employment: Lecturer, Skagit Valley Community College.
Degree: MSc.
Research interests: Older adults.
E-mail: frazierbeth@hotmail.com
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Billie
LINDSEY
Employment: Associate Professor, Department of Physical
Education, Health, and Recreation, Western Washington University.
Degree: PhD.
Research interests: Community health, health risks.
E-mail: Billie.Lindsey@wwu.edu |
|
Lorraine
BRILLA
Employment: Professor, Department of Physical Education,
Health, and Recreation, Western Washington University.
Degree: PhD.
Research interests: Exercise physiology; nutritional
effects on performance.
E-mail: brilla@cc.wwu.edu |
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