The Use Of Trekking Poles In Reducing Muscle Damage Following Mountain Walking: 1728

Abstract

Temporary muscle damage precipitated by downhill walking affects muscle function and potentially exposes muscle to further mus-culoskeletal injury. Purpose: We hypothesized that the use of trekking poles would help maintain muscle function and reduce indices of muscle damage after a day's mountain trekking. Methods: Thirty-seven physically active males (n = 26) and females (n = 11) volunteered to participate and were divided into either a trekking pole (TP) or no pole (NP) group. Participants carried a day sack (5.6 T 1.5 kg) and made the ascent and descent of the highest peak in England and Wales (Mount Snowdon). HR and RPE were recorded during the ascent and descent. Indices of muscle damage, namely, maximal voluntary contraction, muscle soreness, creatine kinase (CK), and vertical jump performance, were measured before, immediately after (except CK), and 24, 48, and 72 h after trek. Results: HR was not different between groups, although RPE was significantly lower in TP during the ascent. The TP group showed attenuation of reductions in maximal voluntary contraction immediately after and 24 and 48 h after the trek; muscle sore-ness was significantly lower at 24 and 48 h after the trek, and CK was also lower at 24 h after the trek in the TP group. No differences in vertical jump were found. Conclusions: Trekking poles reduce RPE on mountain ascents, reduce indices of muscle damage, assist in maintaining muscle function in the days after a mountain trek, and reduce the potential for subsequent injury.

Full text

by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.Copyright @ 2010
Trekking Poles Reduce Exercise-Induced
Muscle Injury during Mountain Walking
GLYN HOWATSON
1
, PAUL HOUGH
2
, JOHN PATTISON
2
, JESSICA A. HILL
2
, RICHARD BLAGROVE
2
,
MARK GLAISTER
2
, and KEVIN G. THOMPSON
1
1
School of Life Sciences, University of Northumbria, Newcastle, England, UNITED KINGDOM;
and
2
School of Human Sciences, St Mary’s University College, Twickenham, England, UNITED KINGDOM
ABSTRACT
HOWATSON, G., P. HOUGH, J. PATTISON, J. A. HILL, R. BLAGROVE, M. GLAISTER, and K. G. THOMPSON. Trekking Poles
Reduce Exercise-Induced Muscle Injury during Mountain Walking. Med. Sci. Sports Exerc., Vol. 43, No. 1, pp. 140–145, 2011.
Temporary muscle damage precipitated by downhill walking affects muscle function and potentially exposes muscle to further mus-
culoskeletal injury. Purpose: We hypothesized that the use of trekking poles would help maintain muscle function and reduce indices
of muscle damage after a day’s mountain trekking. Methods: Thirty-seven physically active males (n= 26) and females (n= 11)
volunteered to participate and were divided into either a trekking pole (TP) or no pole (NP) group. Participants carried a day
sack (5.6 T1.5 kg) and made the ascent and descent of the highest peak in England and Wales (Mount Snowdon). HR and RPE
were recorded during the ascent and descent. Indices of muscle damage, namely, maximal voluntary contraction, muscle soreness,
creatine kinase (CK), and vertical jump performance, were measured before, immediately after (except CK), and 24, 48, and 72 h after
trek. Results: HR was not different between groups, although RPE was significantly lower in TP during the ascent. The TP group
showed attenuation of reductions in maximal voluntary contraction immediately after and 24 and 48 h after the trek; muscle sore-
ness was significantly lower at 24 and 48 h after the trek, and CK was also lower at 24 h after the trek in the TP group. No differ-
ences in vertical jump were found. Conclusions: Trekking poles reduce RPE on mountain ascents, reduce indices of muscle
damage, assist in maintaining muscle function in the days after a mountain trek, and reduce the potential for subsequent injury.
Key Words: DOWNHILL WALKING, LENGTHENING CONTRACTIONS, RECOVERY, MUSCLE DAMAGE
Physical activity has been shown to be an important
factor in the maintenance of health and has been
demonstrated to reduce risk factors associated with
several clinical pathologies (4,20). Walking provides a very
popular mode of physical activity that is accessible to most
individuals regardless of age, sex, or physical condition
(26,28). The popularity of walking is clearly demonstrated
in a recent review, showing that the number of Americans
pursuing hiking activity increased to nearly 30 million in
the year 2004 (7), making hiking activity one of the fastest-
growing outdoor activities in the United States (8).
Trekking in mountain areas poses many challenges, es-
pecially for those who are novices or those who make visits
to these regions infrequently. Principally, mountain trekking
will involve substantial uphill and downhill elements on
uneven and rugged terrain. The uphill ambulation tends to
result in a greater exercise intensity and hence an increased
metabolic cost (21). Conversely, downhill walking results in
a lower metabolic cost than level and uphill walking at the
same absolute speed (19), but it imposes greater forces on
the lower limbs (27), resulting in greater eccentric loading.
These eccentric muscle actions during downhill ambulation
(1,24) can result in temporary exercise-induced muscle
damage (EIMD), which is manifested as reduced muscle
function, muscle soreness (DOMS), efflux of intramuscular
enzymes, limb swelling (12), and reduced reaction time and
position sense (25) that may last for several days after the
exercise bout. The amalgamation of these damaging effects
can be problematic for activity on subsequent days, and
there may be a greater risk of injury due to residual soreness
and perturbations in muscle function (9). Therefore, any
intervention that may help to reduce the negative effects of
EIMD precipitated from trekking could assist in exercise
participation in the days after the initial damaging bout.
Trekking poles are being used with increasing frequency
and are purported to provide increased stability and balance
while trekking on uneven surfaces (13). Much of the re-
search examining trekking poles has focused on biome-
chanical investigations where reduced loading and, hence,
stress to the lower limb, particularly at the ankle, knee, and
hip, have been demonstrated (2,17,27). Pole manufacturers
have suggested that trekking poles can reduce lower limb
Address for correspondence: Glyn Howatson, Ph.D., School of Life
Sciences, Northumbria University, Newcastle, NE1 8ST, United Kingdom;
E-mail: glyn.howatson@unn.ac.uk.
Submitted for publication February 2010.
Accepted for publication April 2010.
0195-9131/11/4301-0140/0
MEDICINE & SCIENCE IN SPORTS & EXERCISE
Ò
Copyright Ó2010 by the American College of Sports Medicine
DOI: 10.1249/MSS.0b013e3181e4b649
140
APPLIED SCIENCES

by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.Copyright @ 2010
joints forces by as much as 25%, whereas other works from
the literature suggest that the use of poles resulted in a load
reduction per stride of 7 kg on level ground, 10 kg uphill,
and 13 kg downhill (23), which equates to 13,500, 28,800
and 33,600 kgIh
j1
, respectively (17). In addition, a recent
study (18) that investigated the prevalence of ankle fractures
sustained during mountain walking has presented a strong
rationale and made recommendations for the use of walking
poles to reduce ankle injury incidence.
In light of the decrease in lower limb joint stress afforded
by trekking poles, it makes the expectation tenable that the
load on skeletal muscle is also reduced and, hence, may pro-
vide a suitable tool to attenuate the muscle damage associ-
ated with trekking, particularly on the downhill elements.
Furthermore, the research has been restricted to laboratory or
nonmountainous outdoor settings, and there are no data ex-
amining the efficacy of trekking poles in ecologically valid
environments, where they are suggested to be of most ben-
efit. Given previous evidence from biomechanical inves-
tigations, the aim of this investigation was to examine the
effects of trekking poles on indices of muscle damage; we
hypothesized that the use of trekking poles would help
maintain muscle function and reduce indices of muscle
damage after a day’s mountain trekking.
METHODS
Subjects. After approval from the institutional research
ethics committee in accordance with the Helsinki Declara-
tion, 37 recreationally active men (n= 26) and women
(n= 11) volunteered for the investigation (mean TSD;
age = 25 T7 yr, stature = 1.75 T0.10 m, mass = 78.0 T16.4 kg,
respectively). Participants completed a health screening
questionnaire and provided written informed consent; fur-
thermore, all participants were instructed to refrain from
strenuous exercise, pharmacological, or therapeutic inter-
ventions for the duration of the investigation.
Protocol overview. Participants were assigned either to
a trekking pole (TP) group (n= 19) or to a no trekking pole
(NP) control group (n= 18) during the ascent and descent
of the highest mountain peak in England and Wales while
carrying a day pack (5.6 T1.5 kg). During the trek, HR and
RPE were recorded. Indices of muscle damage were creatine
kinase (CK), DOMS, maximal voluntary contraction (MVC),
and vertical jump (VJ) performance and were taken before,
immediately after the trek (except CK), and 24, 48, and 72 h
after the trek.
Group allocation. Group allocation was based on two
parameters (sex and current physical activity). Males and
females were separated and ranked according to current
physical activity and were then randomly but equally as-
signed to groups. None of the participants was familiar with
this specific trekking task or was habituated to mountain
trekking. Independent-samples t-test showed no significant
difference between groups for subjects’ characteristics and
physical activity (Table 1). The day before the trek, the
group allocation was disclosed to the participants. Those in
the TP group were issued with a pair of trekking poles
(LEKI, Buffalo, NY); subsequently, a mountain leader with
approximately 27 yr of experience of UK and Alpine moun-
tain trekking provided detailed instruction and coaching on
the correct use until demonstrable competency was attained.
Dependent measures. A 200-mm visual analog scale
was used to determine DOMS with ‘‘no soreness’’ indicated
on one end and ‘‘unbearably painful’’ on the other. Each
participant was asked to squat at 90-and rise to stand and
indicate on the VAS the soreness felt in the lower limbs
(10). A fingertip capillary puncture sample of approximately
100 KL was obtained to determine CK concentration. The
sample was spun in a centrifuge to separate the cell mass
from the plasma supernatant; 30 KL of the plasma was an-
alyzed immediately using a colorimetric slide assay proce-
dure (Reflotron Plus; Roche Diagnostics, Una Health Ltd.,
Stoke on Trent, UK). Intra-assay reliability (CV) for this
method is reported as G3%. VJ height was determined
using a jump mat (Swift Performance Equipment, Lismore,
Australia). Participants stood with feet approximately
shoulder-width apart with hands on hips. On command, they
were instructed to complete a countermovement jump (22).
The best of three efforts was recorded for data analysis.
MVC of the nondominant knee extensors was determined
using a strain gauge (MIE Medical Research Ltd., Leeds,
UK). The strain gauge was attached to the nondominant
ankle while seated on a plinth with the internal knee joint
angle at 80-(verified by a goniometer). Three submaximal
trials at approximately 50%, 70%, and 90% of perceived
maximum followed by two maximal trials, each separated
by 1 min, were completed. If there were 95% variation be-
tween the two MVC trials, a third trial would be adminis-
tered; the highest output recorded on the strain gauge was
used for data analysis. Each contraction lasted for approxi-
mately 3 s, and all participants were given standardized
verbal encouragement throughout (11). HR was recorded
throughout the trek using short-wave telemetry. A combi-
nation of team systems and individually coded HR moni-
tors were used (Polar S610, S810, first-generation Polar
Team system; Polar Electro, Kempele, Finland). The Borg
Scale was used to ascertain RPE (3) on the ascent at ap-
proximately one-third, two-thirds distance, and the summit;
on the descent, it was measured at approximately one-third,
two-thirds distance, and at the start-finish line.
Trek. The day before the trek, all volunteers were trans-
ported to a hostel in the Snowdonia National Park, North
Wales, UK. On arrival, all volunteers were provided with
TABLE 1. Descriptive information of the TP and NP groups.
Group
Sex
(M/F)
Age
(yr)
Height
(m)
Mass
(kg)
PA
(hIwk
j1
)
Pack Mass
(kg)
TP 13:6 26 T9 1.75 T0.10 78.0 T16.7 7.5 T3.5 5.8 T1.4
NP 13:5 25 T5 1.75 T0.11 78.1 T16.5 7.8 T4.1 5.5 T1.7
There were no significant differences between groups. Values are presented as
means TSD.
F, number of females; M, number of males; PA, physical activity.
TREKKING POLES AND MUSCLE DAMAGE Medicine & Science in Sports & Exercise
d
141
APPLIED SCIENCES

by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.Copyright @ 2010
a standardized evening meal and were then rested for the
remainder of the evening before retiring. On the following
morning, participants were fed breakfast before packing
a day sack containing a standardized packed lunch, 2 L of
water, and clothing for potential inclement weather condi-
tions; the pack was then weighed. The official environmen-
tal conditions, according to the UK Meteorological Office,
were as follows: dry with intermittent cloud at 700 m, 11-knot
westerly wind, 9.3-C, 74% relative humidity, and 1007-hPa
barometric pressure.
The trek was guided and supervised by the aforementioned
mountain leader and started on a round trip from Pen-y-Pass
(È350 m altitude) following the Pyg Track to the summit
of Snowdon (1085 m altitude)—a round trip of 11.2 km
and an ascent of 756 m were verified by a global positioning
system (eTrex; Garmin, Olathe, KS). The Pyg Track is a
combination of steep- and gentle-incline sections on uneven
and rough terrain. Participants were transported to the start
line, fitted with an HR monitor, and then placed in one of
four groups (two TP and two NP); each group was led by a
member of the research team departing at 10-min intervals.
The groups were instructed to keep an even pace and maintain
the distance from the group in front. The ascent and decent
were broken into three stages at approximately equal distances
at one-third, two-thirds, and summit. At each point, the time
and participant RPE were recorded. At each checkpoint,
groups took exactly 5 min of rest to adjust clothing and
drink/snack ad libitum; these points of rest were at the same
location during ascent and descent. At the summit, a 20- to
30-min rest was allowed for lunch before departing on the
descent on the same path.
Statistical analysis. Data were analyzed using SPSS
for Windows v.16 (Chicago, IL). All data are reported as
mean TSD. Independent-samples t-test was used to deter-
mine differences for subjects’ characteristics, physical activity
levels,andpackpassbetweengroups.Damageindiceswere
analyzed using a repeated-measures ANOVA (group, 2 (TP,
NP) time 5 (pre, post [except CK], 24 h, 48 h, and 72 h)).
Mean HR and RPE data were analyzed using a repeated-
measures ANOVA (group, 2 (TP, NP) trek section, 6
(asc 1, asc 2, asc 3, des 1, des 2, and des 3)). Mauchly’s test
of sphericity was used to check homogeneity of variance,
and where necessary, violations of the assumption were
corrected using the Greenhouse–Geisser adjustment. Sig-
nificant interaction effects were followed up using least
significant difference post hoc analysis. A significance level
of Pe0.05 was established before analyses.
RESULTS
Descriptive information regarding subjects’ character-
istics, physical activity, and pack mass are presented in
Table 1. Independent-samples t-test showed no significant
differences in any of these variables. The observed power
for the significant interaction and group effects for all
ANOVA were Q0.79 and Q0.51, respectively. The time for
ascent and descent (including scheduled stops) was 4 h
36 min and 4 h 42 min for the TP and NP groups, respec-
tively. Participants in each group started together and made
the entire ascent and descent together. The total time spent
in the ascent and descent for the TP group was 2 h 5 min
and 2 h 6 min, and that for the NP group, this was 2 h 17 min
and 2 h 0 min, respectively.
Seven HR monitors from the team system (two from the
TP and five from the NP group) failed to collect data during
the trek; consequently, HR data reported here reflect this.
During the trek, there was no significant difference (P90.05)
in the mean HR response at any section during the ascent or
descent between groups (both absolute HR and age-predicted
percentage HR
max
). The mean HR responses for the ascent
and descent were 133 and 113 bpm (69%–58% HR
max
)for
the TP group and 137 and 121 bpm (70%–62% HR
max
)
for the NP group. There was a significant group effect
(F=4.196,P= 0.048) and interaction (F=2.585,P=0.028)
for RPE (Fig. 1). Post hoc analysis revealed significantly
FIGURE 1—RPE for the ascent and descent of Mount Snowdon
with the use of trekking poles (TP group) and without (NP group).
Values are mean TSD, n= 37. *Significantly lower RPE in the TP
group (PG0.05).
FIGURE 2—DOMS ratings after the ascent and descent of Mount
Snowdon with the use of trekking poles (TP group) and without
(NP group). Values are mean TSD, n= 37. *Significantly lower DOMS
in the TP group (PG0.05).
http://www.acsm-msse.org142 Official Journal of the American College of Sports Medicine
APPLIED SCIENCES

by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.Copyright @ 2010
lower RPE for the TP group during sections 1, 2, and 3 of
the ascent (Pe0.041) than those for the NP group; there
were no differences in the descent.
All indices of damage showed a significant time effect
(PG0.05). There was significantly less DOMS in the TP
group (F= 4.444, P= 0.042). A rise in soreness was ob-
served after the trek, which peaked at 24 h in both groups. A
significant interaction effect (F= 3.155, P= 0.016) and
subsequent post hoc analysis showed a reduction in DOMS
at 24 h (P= 0.001) and 48 h (P= 0.027) in the TP group
(Fig. 2). No group effect was shown for CK activity (Fig. 3);
however, there was a significant interaction (F= 8.668,
P= 0.001); post hoc analysis revealed lower CK efflux at
24 h in the TP group (PG0.001). Although no significant
differences were observed in VJ, isometric MVC (Fig. 4
showed a significant attenuation of isometric strength loss
in the TP group (F=9.710,P= 0.004). A significant inter-
action (F= 2.494, P= 0.046) and post hoc analysis showed
a reduced loss of strength and a faster recovery in the TP
group immediately after the trek (P= 0.008) and at 24 h
(PG0.001) and 48 h (P= 0.033) after the trek.
DISCUSSION
We hypothesized that the use of trekking poles would
maintain function and reduce the extent of muscle damage
after a day’s mountain trekking. This is the first investiga-
tion to examine the effect of trekking poles on muscle
damage and clearly demonstrates that they can help to
maintain muscle function and reduce EIMD indices after a
day’s mountain trek.
Previous literature has highlighted the importance in be-
ing accustomed to damaging exercise to attenuate the neg-
ative effects of EIMD (12). It was therefore important that
both groups were similarly matched to ensure that the
damage response was comparable. The subjects’ character-
istics and the physical activity levels between groups were
similar in this investigation, demonstrating that the groups
were indeed well matched. In addition, the pack mass of
both groups was also similar, and hence, differences in
function and EIMD indices are unlikely attributable to dis-
crepancies in pack mass or physical activity and condi-
tioning. Furthermore, both groups were unaccustomed to
mountain trekking activity, so differences in damage indices
are likely the consequence of the intervention.
The timings for the ascent and descent were similar be-
tween groups, indicating that the walking speed was also
similar. This is further supported by the nonsignificant dif-
ferences in HR and suggests, metabolically, that the exercise
intensity was comparable between groups. Despite the sim-
ilar responses in HR between groups, RPE was lower in the
TP group during the ascent. With regard to HR, previous
research is conflicting; some studies (6,15) show an increase
in HR with pole use compared with nonuse of poles. The
increase in HR with poles use was suggested to be attributed
to engaging additional muscle mass or increased load car-
riage from the poles; however, these studies were laboratory
based and may not accurately reflect the ground–pole in-
teraction seen in uneven mountain terrains (5). Conversely,
our data are in agreement with others (14,15) who showed
no change in the HR response between conditions (except
for Jacobson and Wright (14), who showed a difference in
the first 50 m) and lower RPE with pole use. Interestingly
Jacobson and Wright (14) are the only other investigators
who used trekking poles outside the laboratory environment
(although on a graded slope rather than on mountainous
terrain). The lower RPE scores shown consistently in the
literature (14–17), and supported by this investigation, are
likely attributable to the additional stability and reduced
lower limb load provided by pole use on the ascending
sections of the trek. It is possible that the TP participants
assumed the poles afforded a benefit when ascending;
FIGURE 3—CK concentration after the ascent and descent of Mount
Snowdon with the use of trekking poles (TP group) and without
(NP group). Values are mean TSD, n= 37. *Significantly lower CK in
the TP group at 24 h (PG0.05).
FIGURE 4—Isometric MVC after the ascent and descent of Mount
Snowdon with the use of trekking poles (TP group) and without
(NP group). Values are mean TSD, n= 37. *Significantly greater iso-
metric force in the TP group after the trek and at 24 and 48 h after the
trek (PG0.05).
TREKKING POLES AND MUSCLE DAMAGE Medicine & Science in Sports & Exercise
d
143
APPLIED SCIENCES

by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.Copyright @ 2010
however, no information was provided by the investigators
before the trek and no participants had experience and pre-
sumably knowledge of trekking poles before the study.
The use of trekking poles has been previously demon-
strated to reduce loading to the lower limb at the ankle, knee,
and hip (2,15,27). On the basis of this strong evidence, we
hypothesized that this would attenuate the extent of muscle
damage sustained from mountain trekking. It is well docu-
mented that downhill ambulation contains a substantial
eccentric component that causes appreciable damage (1,24)
in comparison with uphill ambulation (21). Malm et al. (21)
demonstrated that no increase in muscle damage indices
(CK and DOMS) was evident in an uphill running group
compared with that in a downhill group. Given the signifi-
cant differences in muscle damage indices in our investiga-
tion, it seems likely that the trekking poles had the greatest
effect in attenuating damage on the downhill sections.
Changes in damage indices as a result of eccentric muscle
actions have been discussed extensively in the literature and
are not discussed at length here; for a concise overview of
the damage process, the reader is directed to Howatson and
van Someren (12). DOMS peaked at 24 h in both groups
and was significantly different at 24 and 48 h after the trek,
demonstrating that pole use during mountain trekking re-
duced residual DOMS in the days after the trek. In addition,
CK was also significantly elevated at 24 h in the NP group
and remained close to baseline throughout the time course
in the TP group, illustrating negligible damage in the TP
group. Furthermore, MVC decrements were also negligible
in the TP group in comparison to that in the NP group.
Collectively, this presents strong evidence that trekking
poles reduce the extent (almost to the point of complete at-
tenuation) of muscle damage during a day’s mountain trek.
The reduced muscle damage in the current investigation
was almost certainly attributable to the lower forces to the
lower limbs afforded by the use of poles that is evident from
several biomechanical studies (2,17,27) especially during
downhill ambulation (17,23). Intuitively, these forces are not
lost, rather distributed over a larger area, namely, the upper
body. We asked all participants if they experienced soreness
in any other areas (other than the lower body); 16% (n=3)
of the TP group experienced modest soreness in m. triceps
brachii. Conceivably, the overall damage response could be
due to previous conditioning and susceptibility to the exer-
cise insult; however, we reduced the potential variation by
balancing groups according to sex and current physical ac-
tivity level; there were no differences in subjects’ charac-
teristics or physical activity level, and so, it is seems an
unlikely explanation.
Physical activity is extremely important in the mainte-
nance of health, and walking in mountainous areas is a
popular pastime. However, muscle damage can occur when
there are downhill elements to negotiate, and this might af-
fect the motivation of some to undertake such activity on a
regular basis. It has been established that the negative effects
of muscle damage can lead to reduced muscle function
for many days after exercise where a high degree of force
and reaction time may be required (9). These perturbations
in function could precipitate injury (9) in the days after the
initial insult, and therefore, the use of trekking poles may
help to reduce the incidence of injury on the days after
trekking. A recent article (18) examining the incidence of
hill walkers and ankle injury found that 71% of ankle inju-
ries were sustained by walkers not using poles (the majority
of which were on the mountain descent) and, consequently,
make strong recommendations for walkers to use poles
in mountainous terrain. Although our investigation did not
measure the prevalence of injury, the presence of muscle
damage may increase the potential for injury, and hence, our
investigation supports this recommendation. However, it
is important to acknowledge that it seems likely that a
combination of factors provided by the poles contribute to
the beneficial effects, including greater stability, reduced
loading on joints of the lower limbs, and reduced muscle
damage.
In conclusion, this is the first investigation to examine
the efficacy of trekking poles on indices of muscle dam-
age; furthermore, to our knowledge, it is also the first
documented study to use an ecologically valid environment
to test this type of equipment. We have demonstrated that
trekking poles reduce RPE in mountain ascent and reduce
the extent of muscle damage after a day’s mountain walking.
These findings have strong application for exercisers wish-
ing to engage in consecutive day’s activity in mountainous
terrains by maintaining greater muscle function, reducing
soreness, and, hence, reducing the potential for the preva-
lence of injury.
The authors thank St. Mary’s University College Research Sup-
port Fund for financial support and LEKI, Germany, for providing the
use of trekking poles. Gratitude is extended to Paul Dancy and
Rik Mellor for contributing to logistical points throughout this study.
The results of the present study do not constitute endorsement
by the American College of Sports Medicine.
REFERENCES
1. Ahmadi S, Sinclair PJ, Davis GM. Muscle oxygenation after
downhill walking–induced muscle damage. Clin Physiol Funct
Imaging. 2008;28(1):55–63.
2. Bohne M, Abendroth-Smith J. Effects of hiking downhill using
trekking poles while carrying external loads. Med Sci Sports Exerc.
2007;39(1):177–83.
3. Borg G. Perceived exertion as an indicator of somatic stress. Scand
J Rehabil Med. 1970;2(2):92–8.
4. Butcher LR, Thomas A, Backx K, Roberts A, Webb R, Morris K.
Low-intensity exercise exerts beneficial effects on plasma
lipids via PPARgamma. Med Sci Sports Exerc. 2008;40(7):
1263–70.
http://www.acsm-msse.org144 Official Journal of the American College of Sports Medicine
APPLIED SCIENCES

by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.Copyright @ 2010
5. Church TS, Earnest CP, Morss GM. Field testing of physiological
responses associated with Nordic walking. Res Q Exerc Sport.
2002;73(3):296–300.
6. Ekblom B, Goldberg AN. The influence of training and other
factors on the subjective rating of perceived exertion. Acta Physiol
Scand. 1971;83(3):399–406.
7. Heggie TW. Paediatric and adolescent sport injury in the wilder-
ness. Br J Sports Med. 2010;44(1):50–5.
8. Heggie TW, Heggie TM. Search and rescue trends associated
with recreational travel in US National Parks. J Travel Med. 2009;
16(1):23–7.
9. Howatson G. The impact of damaging exercise on electrome-
chanical delay in biceps brachii. J Electromyogr Kinesiol. 2010;
20(3):477–81.
10. Howatson G, Goodall S, van Someren KA. The influence of cold
water immersions on adaptation following a single bout of dam-
aging exercise. Eur J Appl Physiol. 2009;105(4):615–21.
11. Howatson G, McHugh MP, Hill J, et al. The effects of a tart cherry
juice supplement on muscle damage, inflammation, oxidative stress
and recovery following marathon running. Scand J Med Sci Sports.
2010;20(6):843–52.
12. Howatson G, van Someren KA. The prevention and treatment
of exercise-induced muscle damage. Sports Med. 2008;38(6):
1–21.
13. Jacobson BH, Caldwell B, Kulling FA. Comparison of hiking stick
use on lateral stability while balancing with and without a load.
Percept Mot Skills. 1997;85(1):347–50.
14. Jacobson BH, Wright T. A field test comparison of hiking stick use
on heart rate and rating of perceived exertion. Percept Mot Skills.
1998;87(2):435–8.
15. Jacobson BH, Wright T, Dugan B. Load carriage energy expen-
diture with and without hiking poles during inclined walking. Int J
Sports Med. 2000;21(5):356–9.
16. Kirk J, Schneider DA. Physiological and perceptual responses to
load-carrying in female subjects using internal and external frame
backpacks. Ergonomics. 1992;35(4):445–55.
17. Knight CA, Caldwell GE. Muscular and metabolic costs of uphill
backpacking: are hiking poles beneficial? Med Sci Sports Exerc.
2000;32(12):2093–101.
18. Kumar AJ, Gill DS, Fairweather C, Dykes L. The pattern of
ankle fractures sustained by outdoor activities at the Snowdonia
National Park, North Wales, United Kingdom. Foot Ankle Surg.
2009;15(3):144–5.
19. Laursen B, Ekner D, Simonsen EB, Voigt M, SjLgaard G. Kinetics
and energetics during uphill and downhill carrying of different
weights. Appl Ergon. 2000;31(2):159–66.
20. Lee IM, Buchner DM. The importance of walking to public health.
Med Sci Sports Exerc. 2008;40(7 suppl):S512–8.
21. Malm C, Sjo¨din TL, Sjo¨ berg B, et al. Leukocytes, cytokines,
growth factors and hormones in human skeletal muscle and blood
after uphill or downhill running. J Physiol. 2004;1(556):983–1000.
22. Moir G, Button C, Glaister M, Stone MH. Influence of familiariza-
tion on the reliability of vertical jump and acceleration sprinting
performance in physically active men. JStrengthCondRes.2004;
18(2):276–80.
23. Neureuther G. The ski pole in summer [in German]. MMW Munch
Med Wochenschr. 1981;123(13):513–4.
24. Nottle C, Nosaka K. The magnitude of muscle damage induced by
downhill backward walking. J Sci Med Sport. 2005;8(3):264–73.
25. Paschalis V, Nikolaidis MG, Giakas G, Jamurtas AZ, Pappas A,
Koutedakis Y. The effect of eccentric exercise on position sense
and joint reaction angle of the lower limbs. Muscle Nerve. 2007;
35(4):496–503.
26. Reis JP, Macera CA, Ainsworth BE, Hipp DA. Prevalence of total
daily walking among US adults, 2002–2003. J Phys Act Health.
2008;5(3):337–46.
27. Schwameder H, Roithner R, Muller E, Niessen W, Raschner C.
Knee joint forces during downhill walking with hiking poles. J
Sports Sci. 1999;17(12):969–78.
28. Siegal PZ. The epidemiology of walking for exercise: implications
for promoting activity among sedentary groups. Am J Public
Health. 1995;85(5):706–10.
TREKKING POLES AND MUSCLE DAMAGE Medicine & Science in Sports & Exercise
d
145
APPLIED SCIENCES