Effects of 12 weeks of Nordic Walking and XCO Walking training on the endurance capacity of older adults
Morat et al. European Review of Aging and Physical Activity
Effects of 12 weeks of Nordic Walking and XCO Walking training on the endurance capacity of older adults
Tobias Morat 0
Jenny Krueger 0
Angus Gaedtke 0
0 Institute of Movement and Sport Gerontology, German Sport University Cologne , Am Sportpark Muengersdorf 6, 50933 Cologne , Germany
Background: Several studies have already examined the positive effects of various forms of endurance training in patient groups and in healthy adults up to 60 years old. The aim of this study was to analyse the effects of Nordic Walking (NW) and XCO Walking (XCO) training on endurance capacity in healthy older adults, aged 60 years and older. Methods: Twenty-three older participants (mean age: 69.9 ± 5.4 years) were randomly assigned to either the NW group or the XCO group. All participants were measured before and after the 12 weeks of endurance training (2 sessions/week) to examine oxygen uptake (VO2) and energy consumption during an outdoor field test. In addition, heart rates were recorded and lactate samples were collected. Results: NW mainly demonstrated some significant (p < 0.05) decreases in heart rate, lactate concentration at lower to moderate walking speeds, whereas XCO Walking revealed significant (p < 0.05) decreases in lactate concentration and VO2 at low to higher walking speeds. Conclusions: NW as well as XCO training increase the efficiency of the cardio-vascular system in older subjects. Both training approaches are suitable options for endurance training, which may serve to counteract age- and inactivity-related decreases in cardio-vascular functioning as well as aid in maintaining overall performance in older adults.
Walking; Endurance training; Intervention; Elderly; Seniors; Oxygen uptake; Endurance capacity; Aging; Physical activity
With increasing age, endurance capacity declines and
can lead to functional problems in everyday life [
Several studies in recent years have used Nordic Walking
as the means of choice to achieve positive effects on the
cardiovascular and musculoskeletal system because of the
higher activity in the muscles involved in the Nordic
Walking (NW) technique [
For NW, several studies with different patient groups
(aged 40 years and older) have demonstrated positive
effects on oxygen uptake, perceived exertion [
the anaerobic threshold [
] and the reduction of
body fat [
]. However, the former studies with NW
varied in their study design (cross-sectional, longitudinal
including an intervention), setting (laboratory, field),
walking area (treadmill, walking track), test protocol
(increasing speed, elevation of pitch angle, distance,
duration), and technical instructions [
]. In addition,
most of the NW studies had measurements in laboratory
set-ups, although NW is an outdoor endurance training
form. For example, two intervention studies with NW
were conducted for 50 min, three times a week, for
6 weeks  and 40 min, four times a week, for 13 weeks
]. Chomiuk et al. [
] showed, for example, higher
oxygen uptake values after their NW training
intervention with patients over 65 years of age compared to an
inactive control group. Kukkonen-Harjula et al. [
compared Walking (W) with and without poles and
demonstrated similar reductions of heart rates and
lactate concentrations in both groups with women aged 50
to 60 years. Preuss et al. [
] compared NW, W, Power
Walking and Jogging in 32 healthy persons with a mean
age of 46 years. The authors showed significant higher
values in heart rate and relative oxygen uptake during
NW, compared with W. As a possible explanation a
more difficult arm-leg coordination during NW was
]. Furthermore, the former NW studies with
field tests were cross-sectional in their design and varied
extensively in their testing and training protocols [
A current review  gives a comprehensive overview of
the impact of Nordic Walking in the second half of
lifetime and displays the literature concerning the
effectiveness and safety of Nordic Walking in the therapeutic
rehabilitation of patients of an advanced age. Another
] highlighted the health benefits of NW as
well. Within the reviews, the authors concluded that
heart rate and oxygen uptake values were higher when
compared with W [
Similar effects on the cardiovascular system are
attributed to XCO Walking (XCO), another endurance
training alternative [
]. For XCO Walking, participants use
two XCO trainers (a single XCO trainer is a 27 cm long
closed aluminium tube filled with movable slate
granules, fixed weight: 630–650 g). Participants grab one
XCO trainer with each hand and move them alternating
back and forth during normal walking. With each swing
to the front and back the slate granules hit the end caps
of the XCO trainers, resulting in the XCO-typical
“reactive impacts”, producing a reflexive activation of
antagonist shoulder muscles [
At present, there are just two studies that examined
potential effects of XCO Walking. Two cross-sectional
studies have looked at the muscle activity of the biceps
and triceps, but not during the usual XCO Walking
], and have compared heart rate, oxygen
uptake and energy consumption during the usage of the
XCO trainers versus dumbbells [
]. Only one study
has implemented a longitudinal design with an
intervention period [
]. These authors [
] compared XCO
Walking with walking without any tool in untrained
women (40–60 years). Unfortunately, the XCO group
trained with the interval endurance method and the
walking group with the continuous endurance method.
Due to this flaw, it is not obvious whether the effects
are a result of using the XCO trainers or because of the
different training methods.
In summary, for NW, there are results available for
adults and several patient groups, but for XCO, the
research knowledge is very limited. Both the NW and
XCO studies solely included healthy adults up to
60 years old or specific patient groups; however, the
two endurance training alternatives, NW and XCO,
could be reasonable ways to positively influence the
endurance capacity of older adults aged 60 years and older,
as well as to prevent cardiovascular diseases, for example.
It is questionable whether these two different technique
models, with the dynamic activation of m.biceps brachii
and m.triceps brachii during NW, on the one hand, and
the isometric activation of these two muscles during XCO,
on the other hand, lead to similar effects on the endurance
capacity of older adults.
The aim of this study was to examine the physiological
effects of two endurance training alternatives (NW
versus XCO) on the endurance capacity of healthy
older adults (aged 60 years and older).
The study was conducted as a randomised controlled
longitudinal trial with two parallel training groups (NW
and XCO). Both groups completed 4 weeks of technical
instruction training followed by a 12-week endurance
training. The main assessments were measured prior to
(T1) and after (T2) the 12 weeks of endurance training.
The participants were randomised either to the NW
group using Nordic Walking poles or to the XCO group
using XCO trainers. Both groups obtained 4 weeks of
technical instruction training (twice a week for 60 min)
with their specific training tool (NW poles or XCO
trainers) prior to T1 to get familiar with the correct
technique and handling of their specific device. In
advance of their participation, all of the participants were
fully informed about the purpose and experimental
procedures of the study. All of the participants completed
consent forms. The participants were informed that all
data collected would be processed anonymously. The
study was conducted in the City of Cologne. The study
was conducted according to the Declaration of Helsinki.
The ethics committee at the German Sport University
Cologne granted ethical approval.
Twenty-three older adults (9 men, 14 women) with a
mean age of 69.9 ± 5.4 years (mean body height:
1.68 ± 0.1 m; mean body mass: 77.3 ± 17.5 kg)
participated. The participants were recruited by
advertisements placed on web pages and in local newspapers,
and with flyers in Cologne. Detailed eligibility was
checked via a health questionnaire. Furthermore, the
physicians of potential participants had to provide them
with a medical clearance certificate confirming that
none of the following exclusion criteria were present
(cardiovascular disease, acute infections, renal or
hepatic problems, thrombophlebitis, disc prolapse during
the last year, unstable diabetes, neurological and
neuromuscular diseases, arterial hypertension, diagnosed gait
disorders, artificial joints, osteoporosis, need of walking
aids). Any experience in systematic NW or XCO
Walking within the past 12 months was also a given
exclusion criteria. After the completion of the study, all
participants obtained the possibility to continue
physical activity (endurance training) in a local cooperating
The first intervention phase consisted of 4 weeks of
technical instruction training (TIT; see Table 3 in the
Appendix) and 12 weeks of endurance training (ET; see
Table 4 in the Appendix), 2 sessions a week with at
least 1 day of rest in between sessions (Tuesday and
Thursday). Each session lasted 60 min. The NW group
trained 16 weeks with NW poles, and the XCO group
with XCO® trainers (FLEXI-SPORTS GmbH, Munich,
Germany). At the beginning of each session, there was
5–10 min of warm-up, which was followed by 40–
45 min of the main part of the training with the specific
content and 5–10 min of cool-down. TIT was
implemented to ensure the correct techniques of all of the
participants and to reduce bias in the endurance
fieldtesting results because of uneconomic techniques [
For ET, heart rate (HR) percentage areas were
individually prescribed for each participant (based on their peak
HR during the stress test = 100%). The individual peak
heart rate was taken from the exercise electrocardiogram
during a defined stress test on a cycling ergometer,
which was done by the physicians of the participants.
The peak HR represents the highest HR that was
observed during the stress test. Thus, training intensities
should be interpreted in that context. All of the
participants were equipped with POLAR® HR belts and RS400
monitors (POLAR, Kempele, Finland) during all ET
sessions to control and monitor their HR. Training
intensity was progressively increased over the 12 weeks of ET
(see Table 4 in the Appendix). At first, they started with
60% of their peak HR, this was progressively increased
ending with 85%.
Oxygen uptake (VO2) and energy consumption were
measured with a portable indirect calorimetric device
(MetaMax 3B®, Cortex, Germany) during an outdoor
lactate step test with progressively increasing walking
speeds. Every participant performed the test with the
assigned training tool, either NW poles or XCO trainers,
on a typical 400 m track and field running track with
five progressively increasing speeds (1.0 m/s, 1.2 m/s,
1.4 m/s, 1.6 m/s 1.8 m/s, 5 min per speed, 3 min rest
between stages). In addition, their heart rates were recorded
with POLAR HR belts and RS400 monitors (POLAR,
Kempele, Finland) and lactate samples were collected. The
dependent primary outcome variables were oxygen uptake
[ml/min], energy expenditure [kcal], lactate concentration
[mmol/l] and heart rate [beats/min].
The German Physical Activity Questionnaire 50+ [
was used to examine physical activity, leisure time and
social activities as a secondary outcome. During all ET
sessions, the HR of the participants was recorded with
the POLAR HR belts and RS400 monitors (POLAR,
Kempele, Finland); distance, walking speed and the area
of training were measured through Global Positioning
Data (GPS) as it was done in former studies [
Therefore, an Android Smartphone Galaxy SII
(Samsung, Suwon, South Korea) and the SensorLog
application (version 1.6; Bernd Thomas) was used.
All data are presented as mean (M) ± standard deviation
(SD). All statistics were analysed using the Statistical
Package for the Social Sciences (version 23.0; IBM SPSS,
Chicago, IL). Within this study, an intention-to-treat
analysis with the data of 23 cases was performed.
Missing data were analysed with the MCAR-Test (missing
completely at random) by Little. Afterwards, a multiple
imputation for monotone missing data with 15
] was conducted with SPSS to maintain a
complete dataset of all 23 randomised cases. With the
Shapiro-Wilk test, the normal distribution of the data
was inspected statistically. The baseline characteristics of
the sample were compared with an independent T-test
for normally distributed variables and a
Mann-WhitneyU-Test for all others and non-parametric variables.
Mauchly’s sphericity test and Levene’s test (if necessary
including a Lilliefors correction) were used to test the
sphericity and homogeneity of the variance assumptions,
respectively. A two-factor repeated-measures analysis of
variance (ANOVA), as a mixed design (general linear
model) with the effect of factor one (walking speed
stage) and factor two (measurement session), was used.
In the case of no sphericity, the Greenhouse-Geisser
correction was used. If the ANOVA displayed
significant effects, the estimated marginal means
(EMMEANS) with Bonferroni correction were used
(post hoc) to identify the specific significant differences
between the individual walking speed stages or
measurement sessions (T1 and T2). Eta squared (η2) was
calculated to evaluate small (η2 = 0.02), middle (η2 = 0.13)
or large (η2 = 0.26) effects. An alpha <0.05 was
considered as statistically significant.
The characteristics of the sample displayed no
significant differences between the two groups, NW and
XCO, which was indicative of a successful
randomisation (see Table 1).
The mean values for heart rate during training sessions
displayed no significant differences (p = 0.73) between
groups. In Table 2, all relative heart rates for both
training groups NW and XCO are presented. Taking all 24
training sessions into account, the NW group trained
with a mean relative heart rate of 73 ± 4% and the XCO
group with 75 ± 3%.
An analysis of the GPS data showed neither a
significant difference for total distance (p = 0.95; NW:
4.96 km; XCO: 4.94 km) nor for the mean walking
speed between minute 20 to minute 40 (main part) of
the training sessions (p = 0.93; NW: 6.51 km/h; XCO:
6.49 km/h) between groups (NW and XCO). All routes
within the training sessions covered an area in the
locality of 4 km.
Regarding heart rate, there was a significant (p < 0.05)
effect for the measurement session (p < 0.05) and the
walking speed stage. The NW group displayed a mean
heart rate reduction of 5% between T1 and T2, which
was significant (p < 0.05) at stages 2 and 4. The XCO
group revealed no significant effect of the measurement
session (see Fig. 1).
For lactate concentration results, the ANOVA detected
a significant (p < 0.05) effect of the measurement session
and a significant (p < 0.05) effect for the walking speed
stage at T1 and T2 for the NW group. The NW group
showed a mean reduction of 32% in lactate
concentration through the training with significant differences
(p < 0.01) at stages 1 to 3.
The XCO group showed a significant measurement
session effect (p < 0.01) and a significant walking speed
stage effect (p < 0.05) as well. The XCO group
decreased their mean lactate concentration by about
40% with significant (p < 0.01) reductions for stages 1
to 4 (see Fig. 2).
There was a significant effect of the measurement
session (p < 0.01) for the oxygen uptake (VO2) and of the
walking speed stage (p < 0.01) in the NW group. On
average, through all 5 stages, the VO2 of the NW group
Fig. 1 Means of heart rate [beats/min] in the NW group and the XCO
group before (T1) and after (T2) the 12-week endurance training
during the 5 walking speed stages (stage 1: 1.0 m/s; stage 2: 1.2 m/s;
stage 3: 1.4 m/s; stage 4: 1.6 m/s; stage 5: 1.6 m/s); * = significant
difference (p < 0.05) between T1 and T2 in the NW group; # = significant
difference (p < 0.05) between T1 and T2 in the XCO group
was 12% lower after the training. Post hoc tests showed
a significantly (p < 0.05) lower VO2 at stage 3 and at
stage 5 at T2 compared to T1 (see Fig. 3).
The XCO group showed a significant effect of the
measurement session (p < 0.01) for VO2 and of the
walking speed stage (p < 0.01) as well. The XCO group
displayed a reduction in VO2 through the training
between T1 and T2 by 33% with significant (p < 0.05)
differences for stages 1 to 4 (see Fig. 3).
Energy consumption displayed a significant effect of
the measurement session (p < 0.05) and a significant
effect of the walking speed stage (p < 0.05) for the NW
group. The mean energy consumption for the NW
group was reduced by 15% through the training, post
hoc tests showed a significant difference (p < 0.05) for
stage 1 between T1 and T2. The XCO group showed the
same significant (p < 0.05) ANOVA results for both
factors. A significant (p < 0.01) difference between T1 and
T2 was present for stage 4, and the mean reduction of
energy consumption was 15% in the XCO group.
All means before (T1) and after (T2) the 12 weeks of
training and eta squared of the tests are displayed in
Table 5 in the Appendix. Significant (p < 0.05) post hoc
differences for heart rate, lactate concentration oxygen
uptake and energy consumption between individual walking
speed stages for the NW group and the XCO group are
presented in the Tables 6 and 7 in the Appendix.
The absence of significant differences regarding the
participants’ characteristics is indicative of a successful
randomisation to either the NW or the XCO group prior to
the first training session.
The NW group showed decreased heart rate, lactate
concentration and energy consumption with the same
walking speeds at T1 and T2 after the training period,
particularly at slower to moderate walking speeds.
Further, the NW group decreased their VO2 in moderate to
high walking speeds. The XCO group displayed no
significant differences for heart rate for the comparison
before and after the training period. The XCO group
demonstrated decreases in lactate concentration and
VO2 in slow to high walking speeds (with the exception
of 1.8 m/s). The reductions in heart rate in the NW
group and lactate concentrations in both groups through
the training period can be interpreted as an improved
cardiovascular function or as a response to a reduced
metabolic demand. Regarding VO2, the XCO group
revealed higher average (33%) decreases than the NW
group (12%). However, our study was not conducted in a
crossover design and both groups completed the
outdoor field endurance test before and after the 12 weeks
of training only with their assigned training tool (XCO
trainer or NW poles). Therefore, a direct comparison
between the two training groups is not possible.
In this study, the increase in the metabolic demand
was given by the speed of each walking speed stage.
With this in mind, the change (decrease) in VO2 after
the training period during the same walking speed can
be interpreted as a change of efficiency in the older
adults. Usually, this can be the case due to the technical
component of this type of exercise although all
participants have been taught within 8 sessions and realized
the correct technique. If the training resulted in improved
efficiency (decreased VO2), the reduction in lactate
concentration and heart rate could possibly be explained as a
response to the reduction in the metabolic demand for
the exercise. The positive changes in the measured
parameters imply that both training tools were effective for
maintaining (improving) endurance capacity in healthy
older adults (60 years and older). To further study these
aspects, an identical exhaustive stress test without the
training tools (possibly standardized on a treadmill) before
and after the training period can provide further insights.
A study by Kukkonen-Harjula and colleagues [
demonstrated improvements in both the NW (2.5 ml/
min/kg) and the Walking (W) group (2.6 ml/min/kg) in
peak VO2, energy consumption and lactate
concentration after 13 weeks of NW and W. However, their
sample included women up to 60 years old, their study
included a testing protocol for submaximal and maximal
exercise performance with both NW and W for all
participants, and the authors provided only two instruction
sessions on NW and W. However, authors did not find
statistically significant differences between the study
groups in the submaximal performance tests and no
significant interaction [
]. Other considerations concerning
NW have been predominantly in cross-sectional designs
in the laboratory and in the field as well [
21, 23, 27–29,
]. These author groups demonstrated the advantages of
NW in oxygen uptake, energy consumption, lactate
concentration and heart rate in comparison with normal
walking. For XCO, there are only a few studies, for
example, by Stengel and colleagues , who showed
improved oxygen uptake after their intervention with the
XCO trainers. These authors [
] compared XCO
Walking with normal walking; however, a main problem with
their study and a limitation of its relevance is the
application of two different training methods in the two groups:
Walking (W) and XCO Walking (XCO). The W group
trained with the continuous endurance method, whereas
the XCO group received interval training. Due to this flaw,
one could not conclude whether the effects resulted from
the different training tools or the endurance methods.
Additionally, their participants were 29 untrained women
between 40 and 60 years of age. The same author group
displayed higher cardio-pulmonary, as well as metabolic
stress (oxygen uptake, energy consumption, heart rate) in
participants using the XCO trainers in contrast to using
dumbbells with fixed weights [
Altogether, comparisons between the studies
mentioned are difficult due to differences in the studies’
design, samples, measurement methods and interventions,
and should be taken as additions that lead to a more
comprehensive picture of different ways to improve or
maintain endurance capacity, particularly for the target
group of older adults aged 60 years and older. This study
provides relevant results regarding the two training tools,
Nordic Walking poles and XCO trainers, to improve
endurance capacity in older adults.
The advantages of this study are the identical days and
times-of-day of the (parallel) training sessions, the same
instructors, and the same training methods, walking
speeds and distances. Furthermore, this study consisted
of 4 weeks of technical instruction training and 12 weeks
of endurance training, resulting in a total intervention
duration of 16 weeks. Compared with other studies [
] in this field, it is one of the longest intervention
periods. The intervention design of this study is similar
to the recommendations by Skorkowska-Telichowska et
al. in their review, who suggest NW with professional
trainers 2–3 times a week over at least 3 months. Based
on their review, these authors conclude that the positive
training effects can be maintained over 6–9 months after
the training ends [
Our study examined the effects of NW and XCO
training on the endurance capacity. With the everyday
life of older adults in mind, positive effects through NW
and XCO training on the functional capacity of older
adults can also be an important aspect. For example,
Parkatti et al. [
] observed positive effects of NW and
Walking on different functional tests with significant
differences compared to an inactive control group. These
authors had 40 older adults (mean age of 69 years) doing
9 weeks with two times week and 60 min per session.
However, these authors merged their walking and NW
groups to one intervention group and no further
statements regarding the two forms NW versus Walking can
be made [
In conclusion, both Nordic Walking and XCO Walking
are suitable endurance training alternatives for older adults
(60 years and older) to positively effect heart rate, lactate
concentration and oxygen uptake as parameters of
endurance capacity. Following 8 technical instruction sessions,
the participants of both training groups reached similar
decreases in these parameters by realising training
intensities between 60 and 85% of their individual peak heart
rates in 24 training sessions in the locality of 2 km from
the starting point. Through the training with both NW
poles and XCO trainers, these changes can be interpreted
as a change of efficiency. This study is one of the first to
provide the (long-term: 12 weeks) results of identical and
systematic endurance training using Nordic Walking poles
and XCO trainers in persons aged 60 years and older. Both
NW and XCO are suitable endurance training alternatives
to positively influence the efficiency of the cardiovascular
system and can result in maintained performance to
counteract age-related degradation processes.
The authors thank all the participants and all the bachelor and master
students who helped during data acquisition and the implementation
of the training sessions and made this study possible. Furthermore, the
authors thank A. Schmitz for the analysis of the lactate samples.
First results of this study were presented by the first author at the European
Congress of Sport Science (ECSS) on July, 6th, 2016 in Vienna.
The research was conducted at the Institute of Movement and Sport Gerontology.
This work was supported by the German Sports University Cologne and by
the “Stifterverband fuer die deutsche Wissenschaft” as a part of an excellent
teaching concept (by the first author) in the master study program “sport
and movement gerontology” at the German Sport University Cologne.
Availability of data and materials
The datasets analysed during the current study are available from the
corresponding author on reasonable request.
TM, MP, JL and HGP contributed to conception and design of the study.
TM, JK and AG implemented the measurements and training sessions.
TM and MP analysed the participant data. All authors interpreted and
discussed the results. All authors drafted parts of the manuscript. TM, JK
and AG were major contributors in writing the manuscript. All authors
read and approved the final manuscript.
Ethics approval and consent to participate
The study was conducted according to the Declaration of Helsinki. The ethics
committee at the German Sport University Cologne granted ethical approval.
In advance of their participation, all of the participants were fully informed
about the purpose and experimental procedures of the study. All of the
participants completed consent forms. The participants were informed that
all data collected would be processed anonymously.
Consent for publication
All participants provided consent for publishing their data anonymously.
The authors declare that they have no competing interests.
Springer Nature remains neutral with regard to jurisdictional claims in
published maps and institutional affiliations.
1Institute of Movement and Sport Gerontology, German Sport University
Cologne, Am Sportpark Muengersdorf 6, 50933 Cologne, Germany. 2Institute
of Cardiology and Sports Medicine, German Sport University Cologne, Am
Sportpark Muengersdorf 6, 50933 Cologne, Germany. 3Present Address:
Healthy Campus Bonn, Department 10: Personnel Progress & Career, Rhenish
Friedrich-Wilhelms University Bonn, Walter-Flex-Str. 3, 53113 Bonn, Germany.
1. Chodzko-Zajko WJ , Proctor DN , Fiatarone S , Maria A , Minson CT , et al. American College of Sports Medicine position stand. Exercise and physical activity for older adults . Med Sci Sports Exerc . 2009 ; 41 : 1510 - 30 .
2. Mendonca GV , Pezarat-Correia P , Vaz JR , Silva L , Heffernan KS . Impact of aging on endurance and neuromuscular physical performance: the role of vascular senescence . Sports Med . 2017 ; 47 : 583 - 98 .
3. Murias JM , Paterson DH . Slower VO2 kinetics in older individuals: is it inevitable? Med Sci Sports Exerc . 2015 ; 47 : 2308 - 18 .
4. Parkatti T , Perttunen J , Wacker P. Improvements in functional capacity from Nordic walking: a randomized controlled trial among older adults . JAPA . 2012 ; 20 : 93 - 105 .
5. Rooks DS , Kiel DP , Parsons C , Hayes WC . Paced resistance training and walking exercise in community-dwelling older adults: effects on neuromotor performance . J Gerontol A Biol Sci Med Sci . 1997 ; 52 : M161 - 8 .
6. Tremblay MS , Warburton DER , Janssen I , Paterson DH , Latimer AE , et al. New Canadian physical activity guidelines . Appl Physiol Nutr Metab . 2011 ; 36 : 36 - 46 .
7. Perez-Soriano P , Encarnacion-Martinez A , Aparicio-Aparicio I , Gilmenez JV , Llana-Belloch S . Nordic walking: a systematic review . Eur J Hum Mov . 2014 ; 33 : 26 - 45 .
8. Sokeliene V , Cesnaitiene VJ . The influence of Nordic walking on physical fitness of elderly people . Sportas . 2011 ; 82 : 45 - 51 .
9. Skorkowska-Telichowska K , Kropielnicka K , Bulinska K , Pilch U , Wozniewski M , Szuba A , Jasinski R . Nordic walking in the second half of life . Aging Clin Exp Res . 2016 ; 28 : 1035 - 46 .
10. Tschentscher M , Niederseer D , Niebauer J . Health benefits of Nordic walking - a systematic review . Am J Prev Med . 2013 ; 44 : 76 - 84 .
11. Fritz T , Caidahl K , Krook A , Lundstroem P , Mashili F , Osler M , Szekeres FL , Oestenson CG , Waendell P , Zierath JR . Effects of Nordic walking on cardiovascular risk factors in overweight individuals with type 2 diabetes, impaired or normal glucose tolerance . Diabetes Metab Res Rev . 2013 ; 29 : 25 - 32 .
12. Stroembeck BE , Theander E , Jacobsson LTH . Effects of exercise on aerobic capacity and fatigue in women with primary Sjoegren's syndrome . Rheumatology (Oxford) . 2007 ; 46 : 868 - 71 .
13. Bjersing JL , Dehlin M , Erlandsson M , Bokarewa M , Mennerkopi K. Changes in pain and insulin-like growth factor 1 in fibromyalgia during exercise: the involvement of cerebrospinal inflammatory factors and neuropeptides . Arthritis Res Ther . 2012 ; 14 : R162 .
14. van Eijkeren FJM , Reijmers RSJ , Kleinveld MJ , Minten A , ter Bruggen JP , Bloem R . Nordic walking improves mobility in Parkinson's disease . Mov Disord . 2008 ; 23 : 2239 - 43 .
15. Figueiredo S , Finch L , Mai J , Ahmend S , Huang A , Mayo N. Nordic walking for geriatric rehabilitation: a randomized pilot trial . Disabil Rehabil . 2013 ; 35 : 968 - 75 .
16. Jones K. Nordic walking in fibromyalgia: a means of promoting fitness that is easy for busy clinicians to recommend . Arthritis Res Ther . 2011 ; 13 : 103 .
17. Kawamoto R , Kohara K , Katoh T , Kusunoki T , Ohtsuka N , Abe M , Kumagi T , Miki T . Brachial-ankle pulse wave velocity is a predictor of walking distance in community-dwelling adults . Aging Clin Exp Res . 2015 ; 27 : 187 - 93 .
18. Figard-Fabre H , Fabre N , Leonardi A , Schena F . Efficacy of Nordic walking in obesity management . Int J Sports Med . 2011 ; 32 : 407 - 14 .
19. Aigner A , Ledl-Kurkowski E , Hoerl S , Salzmann K. Effekte von Nordic walking bzw. normalem Gehen auf Herzfrequenz und arterielle Laktatkonzentration [Effects of Nordic walking and normal walking regarding heart rate and arterial lactate concentration] . Oesterreichisches Journal fuer Sportmedizin . 2004 ; 14 : 32 - 6 .
20. Chomiuk T , Folga A , Mamcarz A . The influence of systematic pulse-limited physical exercise on the parameters of the cardiovascular system in patients over 65 years of age . Arch Med Sci . 2012 ; 9 : 201 - 9 .
21. Hoeltke V , Steuer M , Joens H , Krakor S , Steinacker T , Jakob E. Walking vs. Nordic-walking II - Belastungsparameter im Vergleich [Walking versus Nordic-walking II - comparison of load parameters] . Deutsche Zeitschrift fuer Sportmedizin . 2005 ; 56 : 243 .
22. Kukkonen-Harjula K , Hiilloskorpi H , Maenttaeri A , Pasanen M , Parkkari J , Suni J , Fogelholm M , Laukkanen R . Self-guided brisk walking training with or without poles: a randomized-controlled trial in middle-aged women . Scand J Med Sci Sports . 2007 ; 17 : 316 - 23 .
23. Schiebel F , Heitkamp HC , Thoma S , Hipp A , Horstmann T. Nordic walking und walking im Vergleich [Comparison of Nordic walking and walking]. Deutsche Zeitschrift fuer Sportmedizin . 2003 ; 54 : 43 .
24. Walter PR , Porcari JP , Brice G , Terry L . Acute responses to using walking poles in patients with coronary artery disease . J Cardpulm Rehabil . 1996 ; 16 : 245 - 50 .
25. Takeshima N , Islam MM , Rogers ME , Rogers NL , Sengoku N , et al. Effects of Nordic walking compared to conventional walking and band-based resistance exercise on fitness in older adults . J Sports Sci Med . 2013 ; 12 : 422 - 30 .
26. Virag A , Karoczi CK , Jakab A , Vass Z , Kovacs E , Gondos T . Short-term and long-term effects of nordic walking training on balance, functional mobility, muscle strength and aerobic endurance among Hungarian community-living older people: a feasibility study . J Sports Med Phys Fitness . 2015 ; 55 : 1285 - 92 .
27. Preuss M , Preuss P , Mechling H . Nordic walking, walking, Powerwalking und jogging - Sauerstoffaufnahme und Herzfrequenz im Vergleich [Nordic walking, walking, powerwalking and jogging - comparison of oxygen uptake and heart rate] . E-Journal Bewegung und Training . 2008 ; 2 : 1 - 16 .
28. Church TS , Earnest CP , Morss GM . Field testing of physiological responses associated with Nordic walking . Res Q Exerc Sport . 2002 ; 73 : 296 - 300 .
29. Morss GM , Church TS , Earnest CP , Jordan AN . Field test comparing the metabolic cost of normal walking versus Nordic walking . Med Sci Sports Exerc . 2001 ; 33 : S23 .
30. Rudack P , Ahrens U , Thorwesten L , Voelker K. Vergleich der kardiopulmonalen und metabolischen Belastungscharakteristik des Nordic Walkings und Walkings - Konsequenzen fuer die Trainingssteuerung [Comparison of cardio-pulmonary and metabolic load characteristics of Nordic walking and walking - consequences for training control] . Deutsche Zeitschrift fuer Sportmedizin . 2005 ; 56 : 253 .
31. Schiffer T , Knicker A , Montanarella M , Strueder HK . Mechanical and physiological effects of varying pole weights during Nordic walking compared to walking . Eur J Appl Physiol . 2011 ; 111 : 1121 - 6 .
32. Wuepper C , Schulte A , Geese R , Hillmer-Vogel U . Energieumsatz beim walking im Feld-test - Ein Vergleich zwischen walking und Nordic walking [Energy consumption during a walking field test - comparison of walking and Nordic walking] . Deutsche Zeitschrift fuer Sportmedizin . 2005 ; 56 : 249 .
33. von Stengel S , Brandt A , Kemmler W. Einfluss eines 10-woechigen Walking-Programms mit dem XCO-Trainer auf die Ausdauerleistungsfaehigkeit und weitere Parameter der koerperlichen Leistungsfaehigkeit bei untrainierten Frauen zwischen 40 und 60 Jahren [Influence of a 10 week walking program with XCO-Trainers on stamina and additional parameters of physical performance on untrained women between the ages of 40 and 60]. 2009 . http://www.xco-trainer. com/ckeditor_assets/attachments/139/3_studie_XCO_Influence_of_10_ Week. pdf?1439985782. Accessed 06 Jun 2016 .
34. Thoemmes F , Sasse A . Das XCO power -training [The XCO power training] . Munich: BLV; 2009 .
35. van Bruinessen R , Couzy S , van Doorn P , den Hertog K , Weimar A , van de Wetering G. XCO-trainer: empty talk or real effect? 2010 . http://www.xcotrainer.com/ckeditor_assets/attachments/145/7_Study_ XCO_vs_solid_ weight_ HS_Leiden_Jan_2010.pdf?1439986204. Accessed 06 Jun 2016 .
36. von Stengel S , Kalender WA , Kemmler W. Wirkung der “XCO-trainer” im Vergleich zu festen Gewichten auf die Herzfrequenz, die Sauerstoffaufnahme und den Energieverbrauch beim walking und running [Effect of the “XCO-trainer” on heart rate, oxygen intake and energy expenditure in comparison to solid weights while walking and running]. 2008 . http://www.xco-trainer.com/ckeditor_assets/attachments/137/2_ Studie_Effect_XCO. pdf?1439982106. Accessed 06 Jun 2016 .
37. Huy C , Schneider S . Instrument fuer die Erfassung der physischen Aktivitaet bei Personen im mittleren und hoeheren Erwachsenenalter: Entwicklung, Pruefung und Anwendung des “German-PAQ-50+” [Instrument for assessing physical activity of middle-aged and aged persons: development, evaluation and implementation of the German- PAQ- 50 +]. Zeitschrift fuer Gerontologie und Geriatrie . 2008 ; 41 : 208 - 16 .
38. Giannouli E , Bock O , Mellone S , Zijlstra W. Mobility in old age: capacity is not performance . Biomed Res Int . 2016 ; doi:10.1155/ 2016 /3261567.
39. Wettstein M , Wahl HW , Diehl MK . A multidimensional view of out-of-home behaviors in cognitively unimpaired older adults: examining differential effects of socio-demographic, cognitive, and health-related predictors . Eur J Ageing . 2014 ; 11 : 141 - 53 .
40. Jekauc D , Voelkle M , Laemmle L , Woll A . Fehlende Werte in sportwissenschaftlichen Untersuchungen [Missing data in sport science studies] . Sportwissenschaft . 2012 ; 42 : 126 - 36 .
41. Morat T , Mechling H. Training in the functional movement circle to promote strength and mobility-related activities in older adults: a randomized controlled trial . Eur J Ageing . 2005 ; 12 : 105 - 18 .