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ORIGINAL ARTICLE

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A novel incremental slide board test for speed skaters: reliability analysis and comparisons with a

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cycling test

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Tatiane Piucco 1, Ricardo Dantas de Lucas 2, Jonathan Ache Dias 1, Saray Giovana dos Santos 1

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Biomechanics Laboratory, Federal University of Santa Catarina, Florianópolis, Santa Catarina, Brazil. 2
Physical Effort Laboratory, Federal University of Santa Catarina, Florianópolis, Brazil

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* Corresponding author.

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Full mailing address: Universidade Federal de Santa Catarina, Centro de Desportos, Laboratório de

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Biomecânica, 88040-900 / Florianópolis – SC, Brazil

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telephone/fax number: +55 48 3721-8530

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e-mail address: tatianepiucco@yahoo.com.br

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Abstract

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Objectives: This study intended to assess the test-retest reliability of an incremental test performed on a

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slide board (SB) and compare it with a cycling protocol to determine aerobic indexes in skaters. Design:

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Descriptive validity study. Method: Ten recreational inline skaters (eight male and two female) were

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tested. Participants performed two incremental tests on SB and a cycling incremental test. The intensity of

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SB test was determined by cadence, starting at 30 push-offs/min and increasing by three push-offs/min

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each minute, until volitional exhaustion. Maximal and submaximal (related to the heart rate deflection

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point; HRDP) values of oxygen uptake (VO2), pulmonary ventilation (VE), respiratory exchange (RER),

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heart rate (HR) and rating of perceived effort (RPE) were measured. The maximal cadence (CADmax)

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and blood lactate concentration ([Lac]max) were also obtained. Results: No significant differences

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between test-retest on SB were found for all variables. High relative (ICC > 0.9) and absolute reliability

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(typical error of measure as CVTEM < 3.5%) were found for VO2max, HRmax, [Lac]max, CADmax,

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VO2HRDP, CADHRDP, and RPEHRDP. In comparison to SB test, the [Lac]max was significantly higher during

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cycling and RPEHRDP was lower. VO2max, HRmax, CADmax, VO2HRDP and CADHRDP were large

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correlated between cycling and SB (r > 0.8). Conclusions: These findings suggest that SB test is reliable

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and may be used to evaluate aerobic index of skaters.

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Exercise prescription from indices obtained from cycling or running treadmill incremental tests does not

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seem suitable for speed skaters. However, the specificity of laboratory skating assessments remains to be

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established.

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Keywords: skating; slide board; reliability; sport specific testing

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Introduction

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Skating sports involve both aerobic and anaerobic energy supply (Foster et al, 1993; Foster et al.,

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2004; De Koning, Schenau, 2000; Foster et. al 1993). During the start, a large amount of anaerobic energy

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contribution is necessary to accelerate, and then, the last lap is predominantly covered on the basis of

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aerobic power. Even during the last lap of a 1500 m track race the energy is supplied by greater than 90%
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aerobic sources (De Koning, Schenau, 2000). This reveal the importance of aerobic fitness for

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professional in-line or on ice speed skaters.

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Aerobic fitness tests are largely used to monitoring endurance performance, and to control and

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prescribe training intensities during speed skating (Foster et al, 1993). To be effective, the performance

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evaluations for exercise prescription must be valid, reliable and movement-specific. It is generally

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accepted that optimal adaptations can be obtained from training loads specifically related to the sport

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activity itself, due to the physiological and neuromuscular specificity (de Groot et al, 1987, de Boer et al,

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1987b).

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Exercise prescription from measurements obtained from cycling or running treadmill incremental

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tests does not seem suitable for speed skaters (Krieg et al. 2006; Rundell 1996). However, the specificity

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of laboratory skating evaluations remains to be established, particularly because skating activities are

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difficult to simulate in the laboratory (Foster et al, 1993). Since the development of the skating treadmill

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in 1993, there has been little research on the skating treadmill’s validity to elicit a VO2max, or

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determining what type of protocol to use for evaluating physiological indexes (Koepp; Janota 2008). Also,

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skating treadmills are very expensive and challenging to be used by coaches to optimize the training

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programs of athletes through periodic laboratory evaluation.

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Given the importance of aerobic parameter assessment to monitoring inline or on-ice speed

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skaters, it is valuable to develop an appropriate test for these athletes. In this sense, the slide board has

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been widely used as an off-ice training modality by speed skaters, since it seems to mimic the speed

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skating gesture. However, to our knowledge, there are no studies attempting to use it as ergometer, to

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measure incremental testing parameters. The developing of an incremental test using the slide board may

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allow for a simple and low cost sport-specific evaluation of speed skaters.

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Thus, the purpose of this study was twofold: 1) to assess the test-retest reliability of a novel

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incremental test performed on slide board; 2) to compare maximal and submaximal aerobic indexes

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obtained from cycling and slide board incremental tests in recreational inline speed skaters.

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Material and Methods

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Participants

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Eight male and two female recreational in-line skaters voluntarily participated in the study. They

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all had a skating training history of three years, and at least six months of slide board training experience.

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The mean age was 30.6 ± 6 years. The mean body mass, percentage of body fat and height were

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respectively, 71.4 ± 11kg, 17.4 ± 5.7%, and 1.73 ± 0.07 m for males, and 62.3±1.5 kg, 30.9±2.05 % and

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1.66± 2.2 m for females. The study was conducted in accordance with ethical principles for medical

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research involving human and in accordance with ethical standards of the Local University Human

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Research Ethics Committee. All participants signed an informed consent document with a detailed

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description of the aims, benefits and risks of participating in the study, as well as data protection.

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Procedures

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The participants were instructed to refrain from heavy training, maintain a regular diet 24h prior

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to testing, and to abstain from the ingestion of any stimulant (caffeine drink, nicotine, etc) or alcohol

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during the preceding testing day. All participants were familiarized with the tests and the equipment prior

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the data collection.

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Three incremental tests were performed in laboratory-controlled conditions: a maximal

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incremental cadence cycle ergometer test, and two maximal incremental cadence slide board tests to verify

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the test-retest reliability. The tests were performed two to four days apart, at the same time of day and

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room temperature in order to ensure similar environmental conditions.

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Incremental cycling test

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The cycling protocol was performed on a Lode Excalibur Sport Cycle Ergometer (Groninger,

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Holland). Prior to the maximal test, a five-minute warm-up at a workload of 50–60 W with a cadence of

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90 rpm was performed. After a three-minute rest, the participants started the test at an initial workload
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relative to their body weight (2.75 W.kg-1) with the cadence increased by 10 rpm each minute from an

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initial cadence of 70 rpm (Deakin et al., 2011). The test was terminated when the selected cadence could

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no longer be maintained or at volitional exhaustion.

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Incremental slide board test

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The slide board protocol was performed on an instrumented slide board (2.0 x 0.6 x 0.025 cm)

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developed specifically for this project (Figure 1). The slide board surface was made of polyethylene

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(friction coefficient = 0.1) and a non-slip material (Ethylene Vinyl Acetate-EVA) was placed underneath.

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Two optical sensors, connected to a computer, were placed at both extremities of the slide board to detect

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the movement of the athletes’ feet, and to determine the contact time at the lateral stoppers to indicate the

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athletes’ cadence. Specific software was developed to control and help the athlete to keep the pace by

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providing visual and auditory feedback, and also to determine the end of the test by means of the signals

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input from the slide board. The subject wore a pair of fleece socks to skate on slide board during the test.

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The participants performed a five-minute warm-up at a cadence of 30 push-offs per minute. After a three-

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minute rest, the test began with a cadence of 30 push-off/min and it increased by three push-off/min every

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minute. The participants were asked to maintain a constant skating posture, and they were free to move

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their arms during the test. The test was completed when the selected cadence could no longer be

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maintained or at volitional exhaustion. Identical procedures were applied during the re-test.

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FIGURE 1- instrumented slide board scheme. 1- photoemitter; 2- photoreceptor.

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Participants were verbally encouraged to exert maximum effort during the tests. The Rate of

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Perceived Exertion (RPE) during the tests was accessed by the Borg scale (6-20 points) at the end of each

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stage (BORG, 1982). Ventilation (VE), respiratory exchange ratio (RER) and oxygen consumption (VO2)

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were measured breath-by-breath using a gas analyzer (Quark PFT Ergo, Cosmed, Rome, Italy), calibrated

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according to manufacturer’s instructions prior to each test. VO2max was considered to be the highest

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value averaged over 15-seconds. The attainment of VO2max was defined using the criteria proposed by

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Howley et al. (1995). The maximal cadence (CADmax) was defined as the maximal number of push-

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offs/min reached during the slide board test. If the final stage was not completed, the CADmax was

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calculated according to the follow equation adapted from Kuipers et al. (1985):

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CADmax = CADf + (t/60*3),

(1)

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with CADf the cadence of the final stage completed, t the uncompleted stage time, 60 the stage duration

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and 3 the cadence increment per stage. Blood samples were collected from subjects’ earlobe one, three,

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and five minutes following test completion to assess the maximal blood lactate concentration ([Lac]max).
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[Lac] were assessed using an electrochemical analyzer (YSI 2700 STAT, Yellow Springs, OH, USA),

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calibrated according to the manufacturer’s recommendations before each analysis. The D-max method

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(KARA et al. 1996) was used to identify the heart rate deflection point (HRDP), which represents a non-

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invasive method to detect the lactate threshold.

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Statistical Analyses

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A paired t-test was used to compare data obtained from the two slide board trials in a test-retest

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fashion and between the slide board and cycling tests. Heteroscedasticity of all variables were examined

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by Bland-Altman plotting of the absolute individual differences vs the individual means. The slope of the

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linear regression of this data was tested against zero, in order to assess the relationship significance

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(Ludbrook, 2010). Intraclass correlation coefficients (ICC) and typical error of measurement (TEM) were

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calculated according to Hopkins (2000) to determine the test-retest reliability. The TEM was also

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expressed as coefficient of variation (CVTEM). The ICCs were interpreted as follows: 0.90 - 0.99 as high

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reliability; 0.80 - 0.89 as good reliability; 0.70 - 0.79 as fair reliability; and < 0.69 as poor reliability

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(Currier, 1990). Pearson’s correlations were used to examine the relationships between cycle ergometer

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and slide board tests. The following criterion was adopted for interpreting the magnitude of correlation

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between variables: < 0.1 as trivial; 0.11 – 0.3 as small; 0.31 – 0.5 as moderate; 0.51 – 0.7 as large; 0.71 –

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0.9 as very large; and 0.91 – 1.0 as almost perfect (Hopkins et al., 2009). Linear regression was used to

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predict VO2max values from CADmax. Statistical analysis was conducted using Statistical Package for

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Social Sciences (SPSS Inc. v.17.0, Chicago, USA) and the confidence level was set at 5%.

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Results

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During the slide board protocol, all participants reached at least three of five criteria for VO2max

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attainment, according to Howley et al. (1995), 7/10 subjects attained a VO2max plateau, 7/10 attained

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predicted HRmax, 9/10 achieved an RER ≥ 1.1, 9/10 achieved [Lac] ≥ 8 mmol.l-1, and 3/10 attained an RPE

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of 18.
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Table 1 shows test-retest reliability scores of the maximal and submaximal (HRDP) variables. No

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significant differences were found between test and retest values for all variables analyzed. All data

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analyzed presented homoscedasticity. The results show low within-individual variation, very low bias and

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high reliability of VO2, HR and CAD maximal values. Maximal and submaximal values of VE and RER

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showed poor reliability.

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Table 1- Test-retest reliability scores of maximal and submaximal (HRDP) variables (Mean±SD) during

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incremental slide board test.
Test

Retest

CVTEM(%)

ICC (95%CI)

Bias

VO2max (ml.kg-1.min-1)

47.5 ± 7.7

47.6 ± 6.3

3.18

0.97(0.91-0.99)

0.09

HRmax (bpm)

190.9 ± 8.9

189.6 ± 6.8

1.19

0.95(0.800-0.99)

-1.30

RERmax

1.21 ± 0.12

1.15 ± 0.07

7.25

-0.41(-1.86-0.73)

-0.06

VEmax (l.min-1)

115.07 ± 21.4

111.4 ± 19

6.32

0.74(0.03-0.93)

-3.60

CADmax(Push-off.min-1)

64.0 ± 9.3

64.9 ± 9.5

1.21

0.99(0.98-0.99)

0.60

[Lac]max (mmol.l-1)

3.43 ± 0.64

3.42 ± 0.6

6.72

0.92(0.70-0.98)

-0.27

RPEmax

17.2 ± 0.6

17.1 ± 0.5

4.01

0.86(0.47-0.96)

-0.10

VO2HRDP (ml.kg-1.min-1)

42.35 ± 5.4

41.82 ± 5.7

4.90

0.93(0.74-0.98)

0.53

CADHRDP(Push-off.min-1)

53.4 ± 6.9

53.7 ± 8.5

3.47

0.97(0.89-0.99)

-0.30

HRDP (bpm)

175 ± 11.2

171 ± 5.8

3.26

0.72(0.06-0.93)

3.83

VEHRDP (l.min-1)

77.9 ± 8.9

75.9 ± 10.2

8.90

0.68(-0.20-0.92)

2.03

RPEHRDP

15.6 ± 1.4

15.4 ± 1.4

2.84

0.95(0.80-0.98)

0.20

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Bias: Bland-Altam results. VO2max = maximal oxygen uptake; HRmax = maximal heart hate; VEmax =

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maximal ventilation; CADmax = maximal cadence; RERmax = maximal respiratory exchange ratio;

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[Lac]max = maximal lactate concentration; RPEmax = maximal rate of perceived exertion; VO2HRDP =

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oxygen uptake at HRDP; CADHRDP = cadence at HRDP; HRHRDP = maximal heart hate; VEHRDP = maximal

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ventilation; RPEHRDP = rate of perceived exertion at HRDP.

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There were no signifigant differences for maximal VO2, VE, RER and RPE values (Table 2)

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between cycling and slide board tests. Regarding the submaximal values obtained during slide board, only

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RPEHRDP were significantly different (p<0.01) compared to cycling test. Large correlations between

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cycling and slide board for VO2max, HRmax, CADmax, VOHRDP and CADHRDP were found.

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Table 2- Comparison and correlation values of maximal and submaximal variables (Mean±SD) between

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slide board and cycling protocols.
Slide Board

Cycling

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VO2max (ml.kg-1.min-1)

47.5±7.7

48.4 ±8.8

0.91**

HRmax (bpm)

190.9±8.9

190±10

0.87**

RERmax

1.21±0.12

1.29±0.1

0.22

VEmax (l.min-1)

115.07±21.4

127.4±18

0.40

CADmax(Push-off.min-1)

64±9.3

127± 20.5

0.83**

[Lac]max (mmol.l-1)

3.43±0.64

4.49± 0.77*

0.60

RPEmax

17.2±0.6

17.3± 0.48

0.52

VO2HRDP (ml.kg-1.min-1)

42.35±5.4

44.1±6.4

0.90**

CADHRDP(Push-off.min-1) #

53.4±6.9

103±14.9

0.80**

HRDP(bpm)

175±11.2

172.6±12.2

0.32

VE-HRDP (l.min-1)

77.9±8.9

88.3±21.1

0.50

RPE-HRDP

15.6±1.4

14.6±1.5*

0.54

CAD-HRDP(%max)

88.4±4.6

81.7± 8.2

0.50

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* Significant difference (p<0.05); **significant correlation (p<0.05) between slide

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board and cycling. #Cadence values (push-off.min-1) were not compared due to

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different units.

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DISCUSSION

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The first aim of this study was to evaluate the reliability of physiological measures during slide

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board testing, which mimics the skating gesture. No differences were found for all maximal variables

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between test and retest trials. In general, the reliability scores obtained from the slide board test showed

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that it is a practical and consistent incremental test. The VO2max, HRmax, CADmax, CAD and RPE

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submaximal measures showed the highest test–retest reliability scores (ICC>0.9; CVTEM <3.5%, table 1).

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Considering most maximal variables, within-individual variations (TEM) between test and retest were

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smaller than those found for similar protocols in cycle ergometer (Deakin et al. 2010; Zhou, Weston,

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1997) and field hockey skating test (Petrella et al. 2007). Within-participants variation is the most

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important analysis when considering the reliability of measurements, because it affects the estimates

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precision of change in the variable of an experimental study (Hopkins 2000). From a practical point of

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view, Hopkins (2000) pointed out that about 1.5 to 2.0 times the typical error could be used as a threshold

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above which any individual change would be interpreted as “real” following an intervention. For instance,

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considering the CVTEM value found for the CADmax (e.g 1.2%), this threshold would be around 2.4%.

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Comparisons between the slide board test and cycling test indicate higher [Lac]max values and

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lower RPEHRDP during slide board protocol compared with cycling (table 2). Most participants reached a

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slightly lower maximal and submaximal VO2 and VE values and higher HR during slide board protocol.

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Furthermore, significant correlations for VO2max, HRmax, CADmax, VO2HRDP and CADHRDP values exist

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between slide board and cycle ergometer protocols. There is data in the literature comparing the

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physiological parameters amongst skating, cycling and running activities (Martinez et al., 1993; Wallick et

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al., 1995; Foster et al., 1999; Krieg et al., 2006, Snyder et al., 1996; Rundell, 1996). Despite some
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differences, cycling parameters seem to be more similar to skating activity than running (Wallick et al.

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1995, Snyder et al. 1996). Furthermore, the testing protocol design can also affect physiological responses

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during exercise (Bentley et al. 2007). Cadence versus workload incremental cycling tests show differences

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in peak workloads. However, both protocols produce similar peak VO2 values, which reflect on a lower

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cycling economy during cadence-increase protocols (Deakin et al. 2010).

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The findings of the present study are consistent with the previous investigations of Foster et al.

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(1999) and Snyder et al. (1996) that have demonstrated lower VO2, VE and RER values and higher HR

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and [Lac] values during treadmill skating protocol when comparing with cycling exercise. Krieg et al.

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(2006) also found lower VO2max and higher HR and [Lac] values during skating when compared to cycle

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testing, but higher submaximal VO2 and RER associated with a fixed [Lac] of 4 mmol.l-1. Perhaps the

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field skating test conditions in Krieg et al. (2006)’s study could explain those differences, because the

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asphalt friction coefficient and skating variables such as uncontrolled posture, stride frequency, glide and

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push-off duration, crossover stride, can alter physiological responses between treadmill and field skating

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(Nobes et al. 2003). Also, Krieg et al. (2006) utilized a discontinuous protocol and the [Lac] could be

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decreased due to the exercise interruptions, and as well the lactate vs VO2 relationship.

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Other possible explanations for the lower VO2max attained during skating exercise can be related

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to both a smaller active muscle mass and to a restriction of muscle blood flow during skating when

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compared to cycling (Foster et al., 2000, Rundell, 1996, Foster et al. 1999). These conditions depend on

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skating posture, surface characteristics and skater motor skill (Krieg et al. 2006, Carroll et al. 1993). A

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lower skater body position induces a greater reduction in VO2max, consistent with a reduction in muscle

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blood flow secondary to high intramuscular forces during skating exercise (Foster et al., 2000).

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High intramuscular forces could also explain the high HR during skating, since it might lead to a

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disproportionate increase in HR relative to VO2. Such situation is frequently observed during resistance

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training or attributable to the activated muscle ischemia and an increase in systemic arterial pressure

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(O’Leary, 1993). This is consistent with the concept that the high forces within the muscle act to compress

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the smaller arterioles thereby increasing the HR during skating.
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For submaximal comparisons between cycling and slide board modalities, we used the HRDP as

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an aerobic index, obtained from both exercise protocols. The results indicate similar values for VO2, HR

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and VE at the HRDP. Further, the cadence at HRDP found for each ergometer was significantly correlated

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(Table 2). This result suggests that HRDP occurred at the same relative intensity when compared cycling

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and slide board exercises, and the HRDP could be a viable method to prescribe submaximal intensity

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during slide board training. However, a direct method would be necessary to confirm the validity of this

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method of non-invasive lactate threshold determination in such ergometers.

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Since board skating evokes much more specific physiological and biomechanical responses

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(Kandou et al. 1987), it can be used not only for testing, but for training purposes as well. Highly fit

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individuals may require a higher training stimulus to achieve a significant training effect, and slide board

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skating could be used to perform interval-training sessions. Intensity is easily manipulated by changes in

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cadence or by increasing the friction coefficient on the board surface. However, intervention-based studies

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are necessary in order to better understand the likely benefits applied to slide board training compared to

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actual skating movement.

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The good agreement between test-retest data suggests that the slide board incremental test is

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reliable. Furthermore, the large correlations and the lack of differences in the physiological variables

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between the slide board skating and cycling protocols suggest that the slide board may be used to measure

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aerobic variables of skaters similarly to a cycling protocol. Therefore, slide board skate testing may

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provide a more practical alternative to laboratory-based tests when a large number of athletes need to be

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monitored for changes in performance and fitness over a competitive season.

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356
357

TABLES

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361
362
363
364
365
366
367
16

368
369
370
371
372
373
374
375
376
377
378
379
380
381

FIGURE LEGENDS

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17