Gait & Posture 42 (2015) 23–26
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Gait & Posture
journal homepage: www.elsevier.com/locate/gaitpost
The energy expenditure of non-weight bearing crutch walking on the
level and ascending stairs
Jonathan Moran *, Alexandra Murphy, David Murphy, Andy Austin, Danielle Moran,
Caitriona Cronin, Emer Guinan, Juliette Hussey
Discipline of Physiotherapy, School of Medicine, Trinity Centre for Health Sciences, St. James’s Hospital, Dublin 8, Ireland
A R T I C L E I N F O
A B S T R A C T
Article history:
Received 6 May 2014
Received in revised form 19 September 2014
Accepted 22 October 2014
Crutches are commonly prescribed to patients with lower limb dysfunction during rehabilitation to
assist with mobility. The aim of this study was to determine the energy expenditure for non-weight
bearing crutch walking on level ground and ascending stairs at a self selected speed in a healthy adult
population. Thirty-one healthy male and female adults (mean SD: age 21.6 1.2 years; height
170.8 10.8 cm; weight 70.8 11.4 kg) mobilised non-weight bearing with elbow crutches along a 30 m
corridor and (with one crutch) up a flight of 13 stairs.
Energy expenditure for each activity was measured by indirect calorimetry using the COSMED K4b2
portable ergospirometry system. The established VO2 values were 16.4 ml/kg/min for crutch walking on
level ground and 17.85 ml/kg/min for stair climbing. Non-weight bearing crutch walking at a self
selected speed on the level ground and up a flight of stairs resulted in a MET value of 4.57 and
5.06 respectively. The mean heart rate (HR) for crutch walking along the flat was 117.06 20.54 beats per
minute (bpm), while the mean HR for ambulating upstairs with crutches was 113.91 19.32 bpm.
The increased energy demands of non-weight bearing crutch walking should be considered by
physical therapists when instructing patients on crutch use. Further investigation to determine the
implications of these results in populations with chronic disease is warranted.
ß 2014 Elsevier B.V. All rights reserved.
Keywords:
Gait
Crutches
Stairs
Energy
Expenditure
1. Introduction
Collectively, adults aged <20 and 20–29 experience the highest
incidence of lower extremity fractures due to motor vehicle
collisions in the USA [16]. A total of 119,815 reports of lower
extremity injuries due to a variety of reasons occurred in the USA
between January 1st and December 31st 2009 [14]. Strains and
sprains resulted in 36% of all lower limb injuries followed by
contusions and abrasions. Fractures of the toe (38%), lower leg (29%)
and upper leg (31%) were the most common injuries. In the Republic
of Ireland 175.7 per 100,000 people with diabetes underwent lower
limb amputation in 2009 [4]. The rate of non-diabetes related
amputation in 2009 was 9.2 per 100,000 people. A non-weight
bearing gait pattern may be prescribed following lower limb
* Corresponding author. Tel.: +353 863063050.
E-mail addresses: [email protected] (J. Moran), [email protected] (A. Murphy),
[email protected] (D. Murphy), [email protected] (A. Austin), [email protected]
(D. Moran), [email protected] (C. Cronin), [email protected] (E. Guinan),
[email protected] (J. Hussey).
http://dx.doi.org/10.1016/j.gaitpost.2014.10.024
0966-6362/ß 2014 Elsevier B.V. All rights reserved.
fractures, severe sprains or amputations to facilitate independent
mobility and to promote healing. While crutches allow greater
mobility for patients with lower limb conditions [11], the energy
required to non-weight bear using crutches upon discharge, in the
home environment has not been widely considered.
Whilst many studies to date have found that crutch walking
requires more energy than normal walking [1,3,8,22–24] data
regarding energy expenditure while non-weight bearing stair
climbing is weaker. Previous work has reported that the energy
cost of ascending stairs with crutches is greater than crutch
walking on the level ground at predetermined speeds [8].
The energy expenditure of crutch walking ascending stairs at a
self-selected speed has not been quantified. Patient selected speed
is an important factor in energy expenditure as it requires the least
amount of energy expenditure during both assisted and unassisted
mobilisation [10,12,21]. Only one previous study, has measured
crutch mobilisation at self-selected speeds [1]. The results report
that estimated energy expenditure of crutch stairs ascent is higher
than crutch mobilising on the level ground, however energy
expenditure was measured indirectly using rate pressure product,
24
J. Moran et al. / Gait & Posture 42 (2015) 23–26
Healthy adults from the university were recruited to participate
in this study. Male and female subjects were included if they were
aged between 18 and 25. Subjects with a history of a neurological
condition, a cardiovascular disorder, confirmed or suspected
pregnancy, a systemic condition that would affect basal metabolic
rate or a musculoskeletal disorder that would affect walking were
excluded from the study. Ethical approval was granted from The
Faculty of Health Sciences, Ethics Committee, Trinity College
Dublin and written informed consent was obtained from all
individuals.
arrival to the research laboratory and participants were assigned
an individual study identification number. Testing procedures
were standardised and completed by the same member of the
research group for each test. Subject’s height was measured using a
stadiometer in triplicate and averaged for data entry. Weight was
measured barefoot, using a digital scale on the Tanita MC-180MA
multi-frequency body composition analyser, Tanita UK Ltd. Body
mass index was calculated using the following formula: weight
(kg)/height (m2).
Subjects received an education session of up to 10 min which
included demonstration and instructions on a non-weight bearing,
swing through crutch pattern and explanation of the Modified Borg
Rating of Perceived Exertion (RPE) Scale. Non-weight bearing gait
was achieved using elbow crutches. The energy cost of using elbow
crutches has been shown to be comparable to that of using axillary
crutches [1]. Standard elbow crutches (Sunrise Coopers, UK) were
fitted for all subjects according to Mulley’s guidelines (1988) [17]
and subjective feedback from subjects within 2.5 cm [18]. Subjects
were allocated 10 min practice time if needed and were supervised
both on the flat and on the stairs by two members of the research
team. Subjects were randomly required to weight bear on either the
right or left limb following blind selection. Subjects were then fitted
with the COSMED equipment. The face mask was inspected for air
leakage. Prior to each test the COSMED and turbine was calibrated
against gas cylinders of known concentration as per the manufacturer’s instructions. Ultrasound gel was placed on the polar heart rate
monitor which was positioned left of each subject’s xiphisternum.
Before testing, resting HR was obtained each minute for 5 min
with the subject seated and an average was calculated. Subjects
were then instructed to walk at a non-weight bearing self-selected
speed down the corridor. Once completed, HR and time taken were
recorded and subjects were asked to give a score on the Borg RPE
Scale.
Before ascending the stairs (13 steps, step height 16.5 cm)
subjects were required to rest in a seated position until their HR
returned to within five beats of their resting HR [18]. Subjects
ascended the stairs using one hand-rail and carrying the other
crutch in the opposite hand as per Lane and LeBlanc [15]. On
ascending the stairs, HR and time taken were recorded. Subjects
were asked again to give a score on the Borg RPE Scale and testing
was completed. The percentage of maximal HR was calculated
using the age-predicted maximal HR formula (220-age) [9].
3.2. Materials
3.4. Data analysis
The COSMED K4b2, a lightweight portable ergospirometry
system was used to measure the energy demands of non-weight
bearing crutch walking on the level ground and stairs ascent. The
COSMED system analyses cardiopulmonary gas exchange on a
breath-by-breath basis. The COSMED was worn in a comfortable
harness on the shoulders. Heart rate was measured using a POLAR
(T31) heart rate monitor. Data from each subject was telemetrically
transferred to a laptop where it was analysed using the COSMED
software. The COSMED has been shown to have good repeatability
against the metabolic cart (ICC = 0.7–0.9, p < 0.05) [6] and good
validity against the COSMED Quark b2 [7]. The modified Borg Rating
of Perceived Exertion (RPE) Scale was used as a subjective measure of
physical exertion. Chen et al. [5] reported moderate weighted
validity coefficients between RPE scores and VO2max (0.63), % VO2max
(0.64), HR (0.62) and respiration rate (0.72).
Data was described using descriptive analysis. Mean and
standard deviations for baseline subject characteristics and for
each test variable were calculated. The percentage of VO2max at
which each participant worked, for each activity, was calculated
using age allocated normative VO2max values from tables published
by Wilmore and Costill [25].
which is calculated as a function of heart rate (HR) and blood
pressure.
The energy expenditure of mobilising with crutches at a selfselected speed in terms of VO2 must be established. The large
number of lower extremity fractures among <20 and 20–29 age
groups present the need to analyse the energy cost of a non-weight
bearing gait pattern among a similar participant cohort. Improved
understanding of the energy expenditure required to mobilise with
crutches could help inform therapists prescribing crutches.
2. Aims and objectives
The aim of this study was to determine the energy expenditure
for non-weight bearing elbow crutch walking on level ground and
ascending a flight of stairs at a self-selected speed in a healthy
adult population.
The objectives were:
- To determine the energy expenditure, in terms of VO2, required
to ascend stairs with a non-weight bearing crutch pattern at a
self-selected speed.
- To quantify the energy expenditure in METS, needed to ascend
stairs with a non-weight bearing crutch pattern at a self-selected
speed.
- To compare the energy expenditure of non-weight bearing crutch
walking at a self selected speed on the level ground and
ascending stairs.
3. Methodology
3.1. Participants
3.3. Procedure
All subjects were requested to fast for at least 2 h prior to testing
so as to reduce the influence of the thermal effects of food on
energy expenditure values. Written consent was obtained on
4. Results
Thirty six healthy male and female adults between the ages of 18 and 25 were
recruited for this study. Due to technical difficulties, five subjects’ data was not
recorded and so data is presented for 31 subjects only (see Table 1). The mean and
standard deviation was calculated for each of the test variables (see Table 2). Data
for crutch walking on level ground and stair climbing was analysed separately.
4.1. Energy expenditure during crutch walking on level ground and stair climbing
The average VO2 for crutch walking on level ground was 16.39 5.65 ml/kg/min.
The average VO2 for stair climbing was 17.85 5.04 ml/kg/min. Gender differences in
VO2max are well documented with females generally have lower average VO2max values
than males [25] In the current study, when VO2max were analysed by gender, females
tended have a higher percentage VO2 while mobilising on level ground and stairs
ascent, compared to males (Fig. 1), however this was not deemed to be statistically
significant (p 0.05).
J. Moran et al. / Gait & Posture 42 (2015) 23–26
18
Table 1
Baseline characteristics (N = 31, males = 15, females = 16).
Age (years)
Weight (kg)
Height (cm)
BMI
25
Mean
Standard deviation
21.6
70.6
170.8
24.0
1.2
11.4
10.8
2.8
17.5
17
16.5
16
4.2. MET and RPE values for crutch walking on level ground and stair climbing
The average MET value for crutch walking on level ground was 4.57. Stair
climbing with crutches had an average MET value of 5.06, suggesting that
mobilising with a non-weight bearing crutch pattern is a moderate intensity
activity. Participants rated crutch walking on both the level ground (n = 22) and
during stairs ascent (n = 23) either ‘‘easy’’ or ‘‘moderate’’ using the BORG Rate of
Perceived Exhaustion (RPE) Scale.
15.5
15
VO2 ml/kg/min
females flat
VO2 ml/kg/min
males flat
VO2ml/kg/min
females stairs
VO2 ml/kg/min
males stairs
Fig. 1. Average VO2 ml/kg/min for males and females.
4.3. Heart rate during crutch walking along the flat and stairs
The average resting HR was 76.61 12.15 bpm. The mean HR crutch walking
along the flat was 117.06 20.54 bpm while the mean HR during stairs ascent with
crutches was 113.91 19.32 bpm.
4.4. Percentage of Maximal Heart Rate utilised during crutch walking and stair climbing
Males worked at 54.04% of their maximal HR on level ground and 52.19% on the
stairs. Females worked at 63.64% of their maximal HR on the flat and 62.31% on the
stairs. The average HR for males and females on the flat and on the stairs was
calculated and taken as a percentage of maximal HR.
5. Discussion
The results of this study report the energy expenditure of
ascending stairs with crutches is greater than the energy cost of
non-weight bearing crutch mobilising along a 30-m corridor. These
results were consistent with previous work in the area [1,8]. This
study adds to current literature by reporting the energy cost of
non-weight bearing crutch walking on the level ground and
ascending stairs at a self-selected speed measured by pulmonary
gas exchange.
Fisher and Patterson [8] reported the VO2 crutch stair ascent
was higher compared with crutch walking on the level ground,
depending on speed of ambulation. This study reported similar
results using males (n = 15) and females (n = 16) compared to the
all male patients cohorts used by others [1,8]. The results found
that the energy cost of ascending stairs with crutches is higher than
mobilising on the level ground in both males and females. In
contrast to previous work, the measure of energy expenditure in
terms of VO2 using a breath-by-breath analysis allowed for more
direct measures compared to indirect measures of energy
expenditure through HR and blood pressure.
Self-selected walking velocity requires the least amount of
energy expenditure during both assisted and unassisted mobilisation [10,12,21]. In contrast to employing predetermined speeds,
this study allowed participants to self-select the non-weight
bearing crutch speed in order to ensure maximum gait efficiency
and provide a true reflection of daily activities. The average speed
of crutch walking on the level ground was 54.7 m/min equaling an
Table 2
Mean and standard variation of measured variables.
VO2 flat (ml/kg/min)
HR flat (bpm)
Speed flat (m/min)
VO2 stairs ascent (ml/kg/min)
HR stairs ascent (bpm)
Speed stairs ascent (steps/min)
Mean
Standard deviation
16.4
117.1
54.7
17.8
113.9
37.1
5.7
20.5
16.0
5.0
19.3
6.9
energy cost of 16.4 ml/kg/min. The results of this study shows
agreement with the results of Fisher and Patterson [8] who
reported energy expenditure was 14.6 ml/kg/min and 18.0 ml/kg/
min at speeds of 50.5 m/min and 59.8 m/min respectively.
Increasing mobilisation speed appears to correlate with an
increase in energy expenditure on the level ground.
The current study, in addition to previous work in this area,
consists of measuring crutch walking energy expenditure in a
healthy population [1,8,19]. The results of these studies are
consistent, however, there is currently a lack of data assessing the
energy expenditure of elderly individuals or patients with
comorbidities. An inverse relationship exists between older age
and lower aerobic fitness levels [25]. It is possible that non-weight
bearing crutch walking can have higher energy demands on elderly
patients. An estimated percentage of the VO2max needed for elderly
patients to mobilise with crutches on the level ground and up stairs
can be predicted using the percentage VO2max provided by this
study and the normative VO2 data provided by Wilmore and Costill
[25]. For example, in healthy males and females aged between
60 and 69 years, ascending one flight of stairs with crutches would
account for 51.7% and 68.7% of VO2max respectively.
Patient comorbidities may alter the energy demands of specific
activities. The VO2 peak levels of patients with diabetes mellitus
are significantly lower compared to a healthy age-matched patient
cohort [20]. Due to the lower aerobic capacity of the elderly and
comorbidity patients, non-weight bearing crutch walking could be
a more strenuous activity compared to healthy controls. Future
work in this area is warranted.
6. Limitations
There are a number of limitations to this work which the
authors would like to acknowledge. Subjects included in the
current study were aged between 18 and 25 years, and were
compared to the VO2max data provided by Wilmore and Costill [25]
for 20–29 year old participants. As these age groups do not
correspond perfectly there is a small risk of bias due to age related
differences in VO2max [13]. VO2max starts to decrease annually from
age 25 and therefore it is likely that the studied cohort were
slightly fitter than the normative data used for comparison. Due to
the considerable overlap between groups however we feel that this
is unlikely to have had a significant impact on results.
A distance of a 30 m corridor and one flight of stairs was used
which limited the amount of time available to achieve a steadystate HR. A longer time spent crutch walking and stair climbing
would have enabled a steady-state HR to be obtained. Participants
in the study by Fisher and Patterson [8] were required to perform
each activity for 6 min which is considerably longer than the
J. Moran et al. / Gait & Posture 42 (2015) 23–26
26
average of 37 s taken to cover 30 m in this study. In spite of this, the
30 m walk test is a reliable sub-maximal test and has a high
correlation with the 6 min walk test, making 30 m a suitable
distance for testing [2].
[3]
[4]
7. Conclusion
The findings from this study indicate that at a self-selected
speed stair climbing with crutches (VO2 17.8 5.7 ml/kg/min)
places more demand on an individual’s energy expenditure than
normal stair climbing (13.26 ml/kg/min VO2). Energy expenditure has
been shown to be higher when crutch walking up a flight of stairs than
on the level ground in terms of VO2max and METS. Future studies
should examine the energy expenditure of crutch mobilisation on the
level ground and upstairs in clinical populations who may have preexisting muscle strength impairments, lowered exercise tolerance
and co-morbidities.
[5]
[6]
[7]
[8]
[9]
[10]
[11]
Authors’ contribution
[12]
The authors mentioned above have all contributed to the
planning and implementation of this study, the acquisition,
analysis and interpretation of data and in the preparation of the
manuscript. All authors have approved the final version of the
manuscript to be submitted.
[13]
[14]
[15]
[16]
Acknowledgements
This project was financed by Trinity College Dublin and carried
out in the Trinity Centre for Health Sciences, St. James’s Hospital.
The financial providers did not contribute in the implementation of
the study, the analysis or interpretation of the data or the
preparation of the article. The authors would like to thank the
volunteers who participated in this study.
Conflict of interest statement
[17]
[18]
[19]
[20]
[21]
[22]
The authors have no conflicts of interest to disclose.
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