1 23 Self-selected speeds and metabolic cost of longboard skateboarding

Self-selected speeds and metabolic cost of
longboard skateboarding
Wayne J. Board & Raymond
C. Browning
European Journal of Applied
Physiology
ISSN 1439-6319
Eur J Appl Physiol
DOI 10.1007/s00421-014-2959-x
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Eur J Appl Physiol
DOI 10.1007/s00421-014-2959-x
Original Article
Self‑selected speeds and metabolic cost of longboard
skateboarding
Wayne J. Board · Raymond C. Browning Received: 26 March 2014 / Accepted: 15 July 2014
© Springer-Verlag Berlin Heidelberg 2014
Abstract Purpose The purpose of this study was to determine selfselected speeds, metabolic rate, and gross metabolic cost
during longboard skateboarding.
Methods We measured overground speed and metabolic
rate while 15 experienced longboarders traveled at their
self-selected slow, typical and fast speeds.
Results Mean longboarding speeds were 3.7, 4.5 and
5.1 m s−1, during slow, typical and fast trials, respectively.
Mean rates of oxygen consumption were 24.1, 29.1 and
37.2 ml kg−1 min−1 and mean rates of energy expenditure were 33.5, 41.8 and 52.7 kJ min−1 at the slow, typical and fast speeds, respectively. At typical speeds, average
intensity was ~8.5 METs. There was a significant positive relationship between oxygen consumption and energy
expenditure versus speed (R2 = 0.69 (P < 0.001), and
R2 = 0.78 (P < 0.001), respectively). The gross metabolic
cost was ~2.2 J kg−1 m−1 at the typical speed, greater than
that reported for cycling and ~50 % smaller than that of
walking.
Conclusion These results suggest that longboarding is a
novel form of physical activity that elicits vigorous intensity, yet is economical compared to walking.
Communicated by Guido Ferretti.
W. J. Board Department of Health and Exercise Science, Colorado State
University, 220 Moby B Complex, Fort Collins, CO 80523, USA
R. C. Browning (*) Department of Health and Exercise Science, Colorado
State University, 215C Moby B Complex, Fort Collins,
CO 80523‑1582, USA
e-mail: ray.browning@colostate.edu
Keywords Metabolic rate · Oxygen consumption ·
Energy expenditure · Active transport
Abbreviations
ACSMAmerican College of Sport Medicine
ANOVAAnalysis of variance
GPSGlobal positioning system
HzHertz
JJoules
kgKilogram
kmKilometer
kJKilojoule
METMetabolic equivalent
mMeter
minMinute
mlMilliliters
MPHMiles per hour
sSecond
SEEStandard error of the estimate
Introduction
Longboarding is a form of skateboarding in which participants use a skateboard with a longer deck (~0.85–1.05 m)
and wheelbase (~0.75 m) than found on a traditional skateboard (Fig. 1). While traditional skateboards are typically
used for performing tricks (e.g. kickflip or ollie), longboards are designed for traveling at faster speeds, as they
are more stable due to their length, deck height and wide
trucks (connection between wheels and the deck) and
have larger, softer wheels that provide relatively good lateral traction. While longboards are used to descend hills at
fast speeds, they are also used by adolescents and young
adults as a means of active transportation. The increasing
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Fig.  1 a Anatomy of a longboard. Deck length measured
from tip to tail of board. Wheelbase is measured as the distance
between the inside truck bolt
mounts. b Participant longboarding during the study
popularity of longboarding as a form of active transportation is likely due to a combination of their affordability,
portability, relatively fast travel speeds on level and downhill terrain, and the “cool” image associated with the
activity.
To evaluate longboarding as a mode of active transportation, it is insightful to compare the overground speeds and
metabolic cost of longboarding to other common forms of
active transportation. Walking and bicycling are the two
most common forms of active transportation (American
College of Sports Medicine 2006). These activities are popular because they are convenient, easy to learn, relatively
safe and use the existing transportation infrastructure. They
are also health promoting, in that they elevate metabolic rate
and increase daily energy expenditure (Frank 2000; Frank
and Engelke 2001; Oja et al. 1998; Saelens et al. 2003; Sallis et al. 2004). Many studies have quantified self-selected
speeds and metabolic energetics of walking in adults (Inman
et al. 1994; Ralston 1958), and these studies report that selfselected speeds are ~1.3 m s−1 (~4.7 km h−1) (Bornstein and
Bornstein 1976; Browning et al. 2006; Martin et al. 1992). It
has also been well established that adults walk at the speed
that minimizes the gross metabolic cost, with gross metabolic cost values of ~3.0 J kg−1 m−1 typically reported for
normal weight adults (Rubenson et al. 2007). The energetics
of bicycling are also well described in the literature, primarily during cycle ergometry (Burke 2002). To our knowledge,
preferred commuting cycling speed have only been quantified by one study that reported mean commuting speeds of
~4.9 m s−1 (17.7 km h−1) (Dill 2009). The metabolic cost of
cycling increases with speed, though, at typical commuting
speeds, is ~1.0–1.4 J kg−1 m−1 (ACSM 2006; Minetti et al.
2001; di Prampero 1986).
The metabolic costs of legged locomotor activities are
primarily determined by body position, biomechanics and
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aerodynamics. As in walking, longboarding utilizes an
upright body position and requires that the legs be continually repositioned to provide the propulsion necessary
to maintain a steady speed (di Prampero 1986). However, longboarding also has a period of coasting or gliding between propulsive periods, which may result in a
lower metabolic cost of longboarding compared to walking even though the metabolic cost required to overcome
aerodynamic forces would be greater during longboarding
compared to walking due to faster speeds. Compared to
longboarding, bicyclists utilize a more seated or crouched
posture (reducing metabolic cost associated with overcoming aerodynamic forces), support some of their weight via
the saddle/handlebars and do not need to actively reposition
their limbs to provide propulsion to maintain a steady speed
(i.e. there are smaller acceleration-deceleration phases). As
a result, we would expect the metabolic cost of bicycling to
be less than the metabolic cost of longboarding. The form
of locomotion most similar to longboarding is classic style
cross-country skiing (i.e. diagonal stride Nordic skiing).
Both classic style cross-country skiing and longboarding
utilize similar body positions and biomechanics (i.e. alternating phases of propulsion and gliding phases, di Prampero 1986). As a result, the gross metabolic cost of longboarding may be similar to that of classic cross-country
skiing, which has been reported to be ~2.3–2.6 J kg−1 m−1
(Formenti et al. 2005; Bellizzi et al. 1998).
To date, there have been no studies that have measured
typical longboarding speeds or the metabolic rate and cost
required to longboard. Providing metabolic data for longboarding will allow this activity to be assessed as a form
of physical activity. Given the prevalence of sedentary lifestyles among adolescents and young adults (Rey-López
et al. 2008), public health professionals could benefit from
the inclusion of a form of physical activity and active
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transportation that appeals to some younger individuals.
In addition, self-selected speed and physiological data will
assist in evaluating longboarding’s potential as a form of
active transportation and may help transportation planners
as they consider if/how to integrate longboarding into comprehensive transportation plans.
The purposes of this study were to measure typical longboarding speeds and quantify the physiological requirements of longboarding. We hypothesized that: (1) selfselected longboarding speeds would be faster than those
reported for walking and similar to commuter cycling, and
(2) longboarding would require less metabolic energy per
distance traveled (i.e. metabolic cost) than that reported for
walking, greater than the reported metabolic cost of bicycling, and similar to cross-country skiing.
overground speed. To calculate push frequency, we also
measured and timed the number of pushes by their feet per
100 m, as observed in one section of the rectangular loop.
Experimental data
Methods
Overground speed was measured by the GPS unit. GPS
unit speed was verified by comparing average loops speeds
from the GPS unit to speeds calculated with times to complete each loop measured and the distance of the loop. To
determine metabolic rate and energy expenditure during
longboarding, we measured rates of oxygen consumption
and carbon dioxide production with a portable metabolic
measurement system (Oxycon Mobile, Yorba Linda, CA)
that has been validated for use in field studies (Rosdahl
et al. 2010). We calibrated the system prior to data collection, and participants were allowed 4 min to reach steady
state.
Participants
Data and statistical analysis
Seventeen individuals were recruited and participated in the
study. However, data from two participants were not used
due to equipment malfunction (GPS unit loss of satellite
positioning), thus data from fifteen individuals (2 female,
13 male) were used in the study. Participants were experienced longboarders (at least 1 year of longboarding 2 or
more times/week), who were in good health with no known
diseases or limitations to physical activity. Mean age, body
mass and height of participants were 21.0 (1.7) years, 71.5
(8.2) kg and 1.77 (0.07) m, mean (SD), respectively. Participants gave written informed consent that followed the
guidelines of and was approved by the Colorado State University Human Research Institutional Review Board.
The Garmin GPS data were downloaded and exported
using Garmin software. Distance and speed data were
computed from the 1 Hz GPS coordinates and averaged
over the duration of each trial using a custom program
in Matlab (Matlab v 12.0, Mathworks, Natick, MA). We
calculated the average overground speeds, rates of oxygen consumption and carbon dioxide production for the
final 2 min of each trial. We used the overground speed
and the rate of oxygen consumption and carbon dioxide
production data to calculate metabolic rate and metabolic
cost (metabolic rate speed−1) using standard techniques
(Brockway 1987).
Descriptive statistics were calculated for overground
speed, rate of oxygen consumption, metabolic rate, metabolic cost, and energy expenditure. We used linear regression to determine the relationship between oxygen consumption and energy expenditure versus longboarding
speed. One-way, repeated measures ANOVAs were performed on outcome variables to determine if there were
significant differences due to speed: P < 0.05 defined significance. If significant main effects were observed, we
used the Holm-Sidak method to perform post hoc pairwise
multiple comparisons. SigmaPlot version 11.0 (Systat
Software, Inc., San Jose, CA) was used for all statistical
analyses.
Experimental protocol
Participants attended one data collection session. Prior to
data collection, participants were asked to longboard for
10–15 min at a low-intensity effort to warm-up and become
familiar with the longboard model used in this study. Participants then completed three ~6 min trials while traveling at a self-selected slow, typical and fast speeds and
using this standard longboard (Model PF124/Mini Shaka
Complete, Sector 9, San Diego, CA). Participants were
instructed to maintain a steady speed during each trial and
monitored their speed throughout each trial using a wristmounted global positioning system (GPS) unit (Garmin
Forerunner 150, Garmin, Olathe, KS) and handheld stopwatch. Each trial consisted of completing multiple ~350 m
laps on a level street/sidewalk (Fig. 1). The road surface was ~75 % concrete and 25 % asphalt. During each
trial, we continuously measured oxygen consumption and
Results
Mean (SE) longboarding speeds were 3.7 (0.1), 4.5 (0.1)
and 5.1 (0.1) m s−1 (13.3, 16.2, and 18.4 km h−1), during the slow, typical and fast trials, respectively. Speeds
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Fig. 3 Mass-specific gross metabolic cost across the range of speeds
tested. Error bars are SD. Metabolic cost was greater at that fastest
speed compared to the slowest speed. Asterisk indicates significant
difference between fastest and slowest speeds
Fig. 2 Gross mass-specific oxygen consumption (a) and energy
expenditure (b) across the range of speeds used by participants. Both
oxygen consumption and EE increased with speed. Linear regression
equations: VO2 = −9.98 + 9.054 speed (R2 = 0.69, SEE = 4.53,
P < 0.001), EE = −6.11 + 3.68 speed (R2 = 0.78, SEE = 1.47,
P < 0.001), respectively
ranged from 2.8 to 5.9 m s−1 (10.1–21.2 km h−1). As
expected, rates of oxygen consumption and energy
expenditure increased with speed (Fig. 2). Mean (SE)
rates of oxygen consumption were 24.1 (1.1), 29.1 (1.5)
and 37.2 (1.4) ml kg−1 min−1 at the slow, typical and fast
speeds, respectively. Mean (SE) rates of energy expenditure were 33.2 (2.2), 41.9 (2.4) and 52.9 (2.9) kJ min−1
at the slow, typical and fast speeds, respectively. At typical speeds, average intensity was ~8.5 METs, indicating
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Fig. 4 Push frequency across the range of speeds used by participants. Linear regression equation: frequency = −0.421 + 0.20 speed
(R2 = 0.42, SEE = 0.172, P < 0.001)
the activity would be classified as vigorous exercise.
Mean respiratory exchange ratios were 0.74 (0.02), 0.80
(0.02), and 0.84 (0.02) at slow, typical, and fast speeds,
respectively. There was a significant positive relationship between rates of oxygen consumption and energy
expenditure versus speed (R2 = 0.69 (P < 0.001) and 0.71
(P < 0.001), respectively; Fig. 2). Gross metabolic cost
increased slightly with speed (Fig. 3). There was a significant difference between the metabolic cost at the slowest
and fastest speeds. Push frequency increased with speed
(Fig. 4). Mean (SE) push frequencies were 0.30 (0.02),
0.41 (0.05) and 0.54 (0.06) Hz at the slow, typical and
fastest speeds, respectively.
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Discussion
Our results demonstrate that longboarders travel at relatively fast speeds, and that the activity elicits a high metabolic rate (i.e. is classified as vigorous intensity exercise)
while having a relatively low metabolic cost per distance.
As we hypothesized, typical longboarding speeds were
~3.5-times faster than reported self-selected walking speeds
(1.3 vs. 4.5 m s−1) and similar to or slightly slower than
bicycle commuting speeds (4.9 vs. 4.5 m s−1). We found
that gross metabolic cost was ~2.2 J kg−1 m−1, indicating
that longboarding metabolic cost (i.e. economy) is nearly
50 % better than that of walking. The gross metabolic cost
of cycling has been reported to be ~1.0 J kg−1 m−1 at commuting speeds (Tucker 1975) and classic cross-country
skiing of ~2.4 J kg−1 m−1 (Formenti et al. 2005; Bellizzi
et al. 1998), thus we also accept our second hypothesis that
longboarding metabolic cost would be lower than walking,
higher than bicycling and similar to cross-country skiing.
Our results suggest that longboarding may be a physically active way to travel from place to place while expending metabolic energy. Given the self-selected speeds of
~4 m s−1, longboards can be used to travel reasonable distances relatively rapidly. For example, an individual using
a longboard could travel 1.5 km in ~6 min if they used
the typical speeds measured in this study. It would take
~20 min to walk the same distance. The metabolic data
indicate that longboarding at typical speeds requires a vigorous intensity effort of ~8.5 METs. Although similar to a
study that found traditional skateboarding elicited an intensity of ~8.2 METS when used as a means of physical activity (Hetzler et al. 2011), we were surprised to find this level
of intensity in our study given that other forms of active
transportation are typically performed at light-moderate
intensities (2.5–5 METs) (Oja et al. 1998). One possible
explanation is that participants in this study were traveling
faster than they would during a typical trip. This could have
been due to their interpretation of the instructions to travel
at “normal” or “typical” speeds. Our results indicate that
slower speeds of ~3.0 m s−1 would still require a moderatevigorous effort of ~5–6 METs. Given the need for more
individuals, particularly adolescents and young adults, to
engage in moderate-vigorous physical activity (Rey-López
et al. 2008), our results suggest that longboarding may be a
good activity for transportation and improved health.
The metabolic rate (oxygen consumption) and metabolic cost of longboarding increased linearly with speed.
Metabolic rate/cost has been shown to increase curvilinearly with speed in other forms of legged locomotion (di
Prampero 1986), but across a much wider range of speeds
than reported here. We anticipate that the same relationship
would exist during longboarding had we collected data at
faster and slower speeds. The increase in metabolic rate
with speed is likely due to an increase in both non-aerodynamic and aerodynamic factors, although quantification
of these contributions will require further study. Metabolic
rate during longboarding is similar to that reported for classic style cross-country skiing at a similar speed using only
the legs (i.e. no poling, Bellizzi et al. 1998). The similar
rates of oxygen consumption during longboarding and
cross-country skiing are not surprising given the similarities between the two activities in terms of body posture,
and the relatively energy inefficient acceleration-deceleration phases associated with the phases of propulsion and
glide (di Prampero 1986). Furthermore, the gliding phase
during longboarding and cross-country skiing decreases
gross metabolic cost compared to walking and running
(Formenti et al. 2005).
Longboarding is a metabolically economical form of
physical activity. This is not surprising given the mechanics of the task. Individuals push the board every 2–3 s
(0.3–0.5 Hz) and then stand on the board and coast or glide.
Push frequency increased with speed, with values similar
to those found during cross-country skiing (0.6 Hz) (Bellizzi et al. 1998) but lower than typical walking or running
stride frequencies (1–2.5 Hz). Bicycling is regarded as one
of the most metabolically economical forms of humanpowered travel, with an estimated gross metabolic cost of
~1.0 J kg−1 m−1 (Tucker 1975). The difference between
bicycling and longboarding metabolic cost is likely due to
differences in body position, bodyweight support and propulsion mechanics. During bicycling, individuals are in a
crouched sitting position, with the majority of bodyweight
being supported by the saddle. The standing position
adopted during longboarding requires the legs to support
the body and also results in a greater frontal area exposed
to air resistance. The combination of active weight support
(non-aerodynamic), increased aerodynamic drag and a less
efficient propulsion system may contribute to the greater
metabolic cost during longboarding compared to bicycling (di Prampero 1986). While longboarding is relatively
economical when the terrain is level, it is likely that economy would be reduced when traveling uphill. Longboards
likely decelerate quickly when going uphill (particularly
on steeper grades) and the need to push would increase.
There is most likely a grade above which it becomes less
metabolically costly to walk. Future studies that quantify
longboarding energetics at varying grades would confirm
this hypothesis. Conversely, longboarding downhill should
have an economy similar to that of cycling downhill (coasting). Of course, as the downhill grade increases, the need
to brake may increase and potentially increase the metabolic cost. Given the challenges of longboarding uphill
combined with the potential risks of longboarding downhill, longboarding as a form of physical activity seems best
suited for relatively flat terrain.
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While longboarding may be considered a good form
of physical activity, it does have risks unique to the activity. Namely, longboarding requires a level of skill to propel, steer and stop the board. This skill is probably equal
or greater than that required for cycling and, thus, highlights the need for individuals to practice the activity in
order to acquire the necessary skills. In particular, stopping
a longboard can be challenging for a novice, particularly
if the rider is moving relatively fast. Successful integration of longboarding as a physical activity alternative could
be facilitated with programs that teach the basic skills of
riding (similar to bicycling safety/skill programs for children). In addition, the difference between longboarding and
walking speeds highlights the challenge associated with
longboarders and walkers sharing the same path. Given the
similarity of travel speeds of longboarding and bicycling, it
may be more reasonable to have these two forms of activity
share the same infrastructure (e.g. a bike lane) when possible. It should be noted that longboards are not particularly well suited to be ridden in inclement weather, as the
risk of the board slipping laterally increases considerably.
This risk may limit the broad, year-round adoption of longboarding in regions where rain and/or snow are common.
Conclusions
Longboarding is a novel form of physical activity that elicits moderate-vigorous intensity yet is metabolically economical. Travel speeds are similar to commuter cycling but
considerably faster than walking, at least on level terrain.
Given its popularity, longboarding may be an attractive
active transportation option for young adults.
Acknowledgments This research was supported by a grant from
AEND Industries.
Conflict of interest The authors declare that they have no conflict
of interest.
Ethical standards This experiment complies with the current laws
of the United States of America.
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