PEAK POWER OUTPUT TEST ON A ROWING ERGOMETER: A METHODOLOGICAL STUDY BORIS METIKOS,1 PAVLE MIKULIC,1 NEJC SARABON,2
AND
GORAN MARKOVIC1
1
Motor Control and Human Performance Laboratory, School of Kinesiology, University of Zagreb, Zagreb, Croatia; and Department of Health Study, Andrej Marusic Institute, University of Primorska, Koper, Slovenia
2
ABSTRACT Metikos, B, Mikulic, P, Sarabon, N, and Markovic, G. Peak power output test on a rowing ergometer: A methodological study. J Strength Cond Res 29(10): 2919–2925, 2015—We aimed to examine the reliability and validity of the peak power output test on a rowing ergometer (Concept II Model D Inc.) and to establish the “optimal resistance” at which this peak power output was observed in 87 participants with varying levels of physical activity and rowing expertise: 15 male and 12 female physically inactive students (age: 21 6 2 years), 16 male and 20 female physically active students (age: 23 6 2 years), and 15 male and 9 female trained rowers (age: 19 6 2 years). The participants performed countermovement jump (CMJ) test on a force plate, followed by 3 maximal-effort rowing trials using the lowest, medium, and the highest adjustable resistance settings (i.e., “1”, “5,” and “10” on the resistance control dial on the ergometer) in randomized order. The test proved to be reliable (coefficients of variation: 2.6–6.5%; intraclass correlation coefficients: 0.87–0.98). The correlation coefficients between CMJ peak power and rowing peak power (both in watts per kilogram) were fairly consistent across all 3 groups of participants and resistance levels, ranging between r = 0.70 and r = 0.78. Finally, the highest power output was observed at the highest resistance setting in 2 nonathletic groups (p , 0.01), whereas rowers seem to produce the highest power output at the moderate-resistance setting. We conclude that the power output test on a Concept II rowing ergometer may serve as a reliable and valid tool for assessing whole-body peak power output in untrained individuals and rowing athletes.
KEY WORDS muscle power, reliability, validity, measurement
Address correspondence to Goran Markovic,
[email protected]. 29(10)/2919–2925 Journal of Strength and Conditioning Research Ó 2015 National Strength and Conditioning Association
INTRODUCTION
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uman muscle power represents an essential component of physical fitness that is relevant in competitive sports and daily life (18,19,24). In that regard, human muscle power testing is of considerable scientific and practical importance. A number of laboratory- and field-based tests designed for human muscle power assessment have been previously developed and evaluated (for review, see Refs. (8,24,25)). Notably, most of them focus on the action of a particular body segment (e.g., the Wingate cycling test, which primarily entails the activation of the lower extremities) or segments (e.g., the vertical jump test, which entails the activation of the lower extremities and trunk) for completion. However, a test that would assess whole-body peak muscle power, to the best of our knowledge, has not yet been developed and validated. Given the importance of this fitness component from both a sports performance and a lifestyle perspective (3,18,19,24), the assessment of whole-body peak muscle power is worthy of scientific investigation. Rowing entails coordinated muscle action involving the synchronous activity of almost every muscle group in the body (20,21). As such, rowing motion may be a suitable movement pattern for assessing whole-body peak muscle power. Traditionally, rowing has relied upon the use of rowing boats on large bodies of water; however, particularly over the last ;3 decades, various rowing simulators have been developed. This development has greatly improved “offwater” training and testing routines for rowing athletes. However, since these ergometers are now commonly found in various fitness centers and recreational settings, rowing has also become more mainstream within the general, physically active population. The rowing ergometers most commonly used in both sport and recreational settings are various airbraked Concept II rowing ergometer models. When a Concept II rowing ergometer is used, the force against which each user must row on this type of ergometer is based on air resistance to a bladed flywheel enclosed within a cover equipped with an adjustment mechanism that allows for a range of possible settings from 1 to 10. Note that the resistance setting 1 (lowest adjustable resistance) corresponds to the drag factor of 90, and resistance setting 10 (highest adjustable resistance) corresponds to the drag factor 200. VOLUME 29 | NUMBER 10 | OCTOBER 2015 |
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Power Output Test on a Rowing Ergometer Drag factor is a numerical value for the rate at which the flywheel decelerates; this value changes in accordance with the volume of air that passes through the flywheel housing. Performance monitors on a Concept II rowing ergometer may provide feedback in terms of distance rowed, speed, pace, calories, and power for each workout; however, a Concept II rowing ergometer measures neither force nor velocity during rowing. Since power output is a direct product of these 2 parameters, its output regarding these performance monitors perhaps should not be considered a valid indicator of human muscle power. Moreover, for any power test, there exists an optimal resistance at which the person being tested can generate his or her peak power output (3,19). Given that peak power output depends on interplay between resistance and movement velocity, the optimal resistance at which rowing activity on a Concept II rowing ergometer yields peak power is also currently unknown. With this in mind, the aims of this study were to evaluate the reliability and validity of peak power output on a Concept II rowing ergometer and to establish the “optimal resistance” at which this peak power output was observed in participants with varying levels of physical activity and rowing expertise. If shown to be valid and reliable, this power output test on a rowing ergometer may become a useful tool for the assessment of whole-body peak muscle power in both sports and recreational settings.
METHODS Experimental Approach to the Problem
We applied a cross-sectional study design for examining the reliability and validity of the peak power output test on a Concept II rowing ergometer and for establishing the resistance setting that maximizes peak power output during rowing. For this purpose, we tested 3 groups of participants with different levels of physical activity and skill. Testing was performed within 1 visit, on the same time of day to avoid circadian variation. A randomly chosen subgroup of participants visited the laboratory for the second time 48 hours after the first visit (reliability study). Subjects
The sample for our study comprised 87 participants. There were 27 individuals with a low level of physical activity, 36 physically active individuals, and 24 rowing athletes. In particular, physically inactive group consisted of 15 men (age: 22 6 2 years; body height: 1.82 6 0.06 m; body mass: 77 6 13 kg) and 12 women (age: 20 6 1 years; body height: 1.64 6 0.06 m; body mass: 59 6 9 kg); physically active group consisted of 16 men (age: 24 6 2 years; body height: 1.80 6 0.05 m; body mass: 81 6 12 kg) and 20 women (age: 23 6 2 years; body height: 1.70 6 0.07 m; body mass: 63 6 7 kg); rowing group consisted of 15 men (age: 20 6 2 years; body height: 1.85 6 0.06 m; body mass: 84 6 8 kg) and 9 women (age: 18 6 2 years; body height: 1.69 6 0.07 m; body mass: 62 6 8 kg). All the participants were informed about
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the aims of this study and about possible risks related to participation before providing their written consent to participate. Athletes aged ,18 yrs in our study participated in it only after written informed consent had been received from their parents, as well as from their coaches. The study was approved by the Scientific and Ethics Committee of the School of Kinesiology at the University of Zagreb. We used the International Physical Activity Questionnaire, Croatian, short version (12) for classification of individuals based on their level of physical activity into 3 categories: high, moderate, and low level of physical activity. The participants with a low level of physical activity in this study were students at the Polytechnic of Zagreb, whereas the physically active participants (i.e., those with moderate and high level of physical activity) in this study were students at the School of Kinesiology at the University of Zagreb. Finally, the group of rowing athletes comprised randomly selected junior-level athletes from 2 rowing clubs in Zagreb, Croatia with at least 2 years of regular experience of rowing training. Testing Procedure
For all participants, stature was measured to the nearest 0.01 m using an anthropometer (GPM, Zurich, Switzerland), and body mass was assessed to the nearest 0.1 kg using a beam balance scale (Seca, Hamburg, Germany). The participants then underwent a standardized warm-up procedure that consisted of biking on a stationary bike at 75 W for 5 minutes, as well as a set of dynamic stretching exercises (shoulder circles, arm swings, hip twists, leg swings, lunges, toe touches) with 10 repetitions per exercise, and a set of body-weight strength exercises (squats, push-ups, sit-ups, lying back extensions, and lunges) with 10 repetitions per exercise. They subsequently familiarized themselves with the context of the rowing ergometer by rowing comfortably at their own pace for 5 minutes. After a short break lasting 2–3 minutes, the participants performed a countermovement jump (CMJ) test on a Kistler Quattro Jump force plate at a sample rate of 500 Hz. This jump was used to validate the peak power output yielded on the rowing ergometer (see further text). The rationales for using CMJ as a reference test for short-term power output measurement are its high validity and reliability (8,14), and its bilateral nature of activation of leg and hip muscles (14,15). All other standard tests of short-term power output involve either pure unilateral (e.g., isokinetic joint testing) or alternating unilateral movement patterns (e.g., cycling, staircase running) (24,25). The subjects began this test from an upright standing position with their hands on their hips. They performed a preliminary downward movement by flexing at the knees and hips. The knees and hips were immediately extended again for a maximal vertical jump (15). One practice and 2 official trials were performed, with the trial with the highest power output (in watts per kilogram) used in further analyses. Rest between jumps was 1 minute. Power output was calculated as a product of the vertical component of the
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Journal of Strength and Conditioning Research ground-reaction force and the velocity of the center of mass (15). The velocity of center of mass was obtained from the integral of the acceleration provided by the vertical force signal (15). After the CMJ test, the participants performed the peak power output test on a rowing ergometer (Model D; Concept II, Inc., Morrisville, VT, USA). The test consisted of 3 trials separated by 3-minute rest periods, with each trial characterized by a different resistance setting on the resistance control dial of the ergometer. For these trials, we set the control dial at 1 (lowest adjustable resistance), 5 (medium adjustable resistance), and 10 (highest adjustable resistance), corresponding to drag factors of 90, 125, and 200, respectively. These 3 trials were performed in randomized order. For each trial, the participants were instructed to perform 6 “introductory” strokes followed by 6 “all-out” strokes. The stroke rate during all rowing tests ranged between 35 and 45 per minute. The highest external power output yielded during these 6 “all-out” strokes (in watts per kilogram) at each resistance setting was recorded as the peak power output. A similar procedure for peak power output assessment on Concept II rowing ergometer was also applied by Gee et al. (6) and Ingham et al. (10). Participants did not receive any visual or verbal feedback during the rowing ergometer test. Peak power output tests on a rowing ergometer were conducted on a custom equipped rowing ergometer (Model D; Concept II). Movement of the handle was measured by an encoder (model RI 30-B; Hengstler, Aldingen, Germany) mounted on the axis of the flywheel. Pull force developed at the rowing handle was detected by a small strain gauge traction sensor (model U9B; Hottinger-Baldwin Messtechnik, Darmstadt, Germany) mounted between the handle and the chain connected to the flywheel. The signals were synchronously sampled at 1,000 Hz by a data acquisition card (model NI USB 6212; NI, Austin, TX, USA) and stored on a personal computer. Software for data acquisition, signal postprocessing, and analysis was custom developed (LabVIEW 2013; NI).
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To assess test-retest reliability of this measure, 16 randomly chosen participants (8 men) from the “physically active” group (age: 23 6 2 years; body height: 1.75 6 0.07 m; body mass: 71 6 13 kg) were asked to return to the laboratory 48 hours after the initial round of testing. At that second visit, they underwent the same warm-up routine as during their initial testing, and they repeated, again in a randomized order, the 3 trials of the peak power output test on a rowing ergometer. Statistical Analyses
Mean values and SDs were determined. In line with methodological recommendations (1,7), the following 3 components of reliability were calculated: (a) systematic bias, (b) within-individual variation, and (c) retest correlation. Before these reliability components were calculated, data had been assessed for heteroscedasticity, with the SD of the 2 trials of each participant plotted against the mean of the 2 trials of each participant. Since no evidence of heteroscedasticity was found, we continued to perform the reliability analyses as follows. Systematic bias in performance variables was assessed using a paired t-test. We also calculated Cohen’s d for dependent groups. Within-individual variation was assessed using coefficients of variation (CV) and SEs of measurement that were established using a 2-way analysis of variance (ANOVA) as follows: the participants represented a random effect; the number of tests in a sequence was a fixed effect, while the raw (for SEs of measurement) or log-transformed (for CV) performance measurement was a dependent variable. The SEs of measurement represented the square root of the mean square error term (RMSE) in the ANOVA output. The mean CV was then calculated based on the RMSE using the following formula: CV = 100 (eRMSE 2 1) z 100$RMSE (9). Finally, the retest correlation was assessed using a 2-way mixed model of intraclass correlation coefficient (ICC) described by Shrout and Fleiss (22). The 95% confidence intervals (CIs) for both ICCs and CVs were also calculated. To examine the validity of this measure, we calculated correlation coefficients between peak power output measures
TABLE 1. Reliability of the peak power output test using a rowing ergometer.*
Test 1 (mean 6 SD) (W$kg21) Test 2 (mean 6 SD) (W$kg21) Mean difference (T2 2 T1 [95% CI]) (W$kg21) Cohen’s d t-test, T1 2 T2 (p) SEM (95% CI) (W$kg21) CV (95% CI) ICC (95% CI)
Low resistance
Medium resistance
High resistance
15.5 6 4.2 16.5 6 4.0 1.0 (0.7–1.5) 0.24 ,0.001 0.5 (0.4–0.8) 4.5 (3.3–7.0) 0.95 (0.93–0.99)
15.8 6 3.7 16.6 6 3.4 0.8 (0.2–1.5) 0.22 0.013 0.9 (0.7–1.4) 6.5 (4.7–10.2) 0.87 (0.81–0.97)
16.5 6 3.7 16.7 6 3.7 0.2 (20.1–0.5) 0.05 0.148 0.4 (0.3–0.6) 2.6 (1.9–4.0) 0.98 (0.97–1.00)
*CI = confidence interval; CV = coefficient of variation; ICC = intraclass correlation coefficient.
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Power Output Test on a Rowing Ergometer
TABLE 2. Peak power output generated on a rowing ergometer in 3 groups of participants and across 3 resistance levels.*
Low-resistance setting (mean 6 SD) (W$kg21) Medium-resistance setting (mean 6 SD) (W$kg21) High-resistance setting (mean 6 SD) (W$kg21) Change in mean: low vs. medium resistance (95% CI) Change in mean: medium vs. high resistance (95% CI)
Physically inactive participants
Physically active participants
Rowing athletes
10.9 6 3.8
14.7 6 4.1
23.5 6 5.2
12.6 6 4.1
15.8 6 3.5
23.8 6 5.0
13.4 6 4.1
16.2 6 3.8
23.3 6 5.1
17.0 (12.3 to 21.9)
8.8 (4.6 to 13.2)
1.4 (21.2 to 4.0)
6.8 (3.1 to 10.6)
2.3 (20.7 to 5.3)
22.0 (23.5 to 20.6)
*CI = confidence interval.
achieved using the rowing ergometer, and mass-specific peak, and mean power output achieved during the concentric phase of CMJ test. The magnitude for correlation coefficients were considered as trivial (r , 0.1), small (0.1 , r , 0.3), moderate (0.3 , r , 0.5), large (0.5 , r , 0.7), very large (0.7 , r , 0.9), nearly perfect (r . 0.9), and perfect (r = 1.0), in accordance with Hopkins’ definitions (Hopkins, 2000). Differences in rowing peak power output across 3 resistance levels within each group were determined using repeated measures ANOVA and Bonferroni post hoc test, respectively. The level of significance was set at p # 0.05.
RESULTS Reliability data for peak power output test using a rowing ergometer are presented in Table 1. The test consisted of 3 trials corresponding to 3 resistance settings on the adjustment mechanism of the ergometer (i.e., low-, medium-, and highresistance settings), and these trials were conducted using a subgroup (N = 16) of randomly selected physically active participants. Note that a small systematic bias (Cohen’s d = 0.22–0.24; p # 0.05) in peak power output was observed for low- and medium-resistance settings. Also, note relatively small within individual variations (CVs = 2.6–6.5%) and high retest correlations (ICCs = 0.87–0.95) across all resistance setting. Table 2 presents mean values and SDs for 3 trials of the peak power output test using a rowing ergometer. These data are presented for all 3 groups of participants, and the relative changes between trials (with corresponding CIs) are also presented. Repeated measures ANOVAs revealed significant within-group differences in peak power output among 3 resistance settings for physically inactive (F = 60.3; p , 0.01) and physically active participants (F = 12.8; p , 0.01), but not for rowing athletes (F = 2.1; p = 0.13). In physically inactive
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group, post hoc comparisons revealed significant differences (p # 0.05) in peak power output among all pairs of resistance settings, whereas in the physically active group, only differences between low- and medium-, and low- and highresistance settings were statistically significant (p # 0.05). Correlation coefficients between mass-specific peak CMJ power output (in watts in kilogram) and peak power output on a rowing ergometer (in watts in kilogram) at low, moderate, and high resistance levels were as follows: group of individuals with a low level of physical activity, r = 0.72, 0.74, and 0.76; group of physically active individuals, r = 0.70, 0.72, and 0.72; and group of rowing athletes, r = 0.76, 0.76, and 0.78.
DISCUSSION In this study, we aimed to establish the reliability and validity of the newly constructed test for the assessment of wholebody peak power output using a rowing ergometer. The calculated components of reliability and validity generally suggest that the peak power output test on a rowing ergometer may serve as a reliable and valid tool for assessing whole-body peak power output in healthy, physically active individuals. We also aimed to determine the resistance setting on a Concept II rowing ergometer at which the highest peak power output values are observed. We found that, to achieve the highest values of peak power output, the resistance control dial should be set at the highest allowable setting (i.e., 10 on the resistance control dial) for the general population regardless of the applicable level of physical activity; however, this does not apply to rowing athletes who seem to generate the highest power output with the resistance control dial set at 5 (i.e., “medium” resistance setting). This is likely due to adaptation to specific rowing training in which similar resistance levels are used by rowers when rowing on a Concept II rowing ergometer.
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Journal of Strength and Conditioning Research Regarding the reliability measures, the systematic bias was quantified by means of an analysis of changes in the mean values between the tests. The observed changes in the mean values of peak power output variable from test 1 to test 2 were of small magnitude (Cohen’s d = 0.05–0.24) and ranged from 0.2 W$kg21 (1.2%) for the high-resistance setting, over 0.8 W$kg21 (5.1%) for the medium-resistance setting, to 1.0 W$kg21 (6.5%) for the low-resistance setting. The “relative” reliability of peak power output proved to be high to very high across all resistance settings: ICC ranged from 0.87 for the medium-resistance setting, over 0.95 for the lowresistance setting, to 0.98 for the high-resistance setting. Finally, “absolute” reliability measurements indicated that the coefficient of variation ranged from 2.6% for the highresistance setting, over 4.5% for the low-resistance setting, to 6.5% for the medium-resistance setting. The corresponding SEs of measurement ranged from 0.4 W$kg21, over 0.5 W$kg21, to 0.9 W$kg21, respectively. All the calculated components of reliability indicated that the peak power output test using a rowing ergometer performed at highresistance setting yielded the highest reliability, as the smallest change in mean, the highest ICC, and the smallest CV and SEM were recorded for this particular resistance setting. This observation is perhaps important, as the highest peak power output values across 3 resistance settings were also recorded for this particular resistance setting (see further discussion). In comparison with other power output tests, the reliability data indicate that, for example, the correlation coefficients for the Wingate cycling test in children and young adults generally amount to about r = 0.95 for peak power output (9). Coefficients of variation for various shortduration power tests on a cycle ergometer typically range between about 2 and 6% (8), which places the data from this study within this established range. The reliability data have also been established for the Wingate rowing test (17), and the ICC amounted to 0.97 with CV equaling 7.3% for maximal power output. Countermovement jump, however, produced CV of about 2.5% (14). When designing this study, we tried to anticipate the extent to which the successful execution of the rowing motion would present a challenge for our participants. The fact is, a basic rowing technique is very easy and straightforward in theory, but, in practice, it is challenging to achieve because it is complicated by the need for coordinated muscle action involving the synchronous activity of the lower extremities, trunk, and upper extremities. Although this coordinated muscle action of every major muscle group in the body certainly makes the newly constructed test suitable for assessing whole-body power, there are certain drawbacks, as some coordination abilities are necessary for the successful completion of this test. This coordination requirement, for example, is much less pronounced in many other power output tests that activate a smaller percentage of muscle mass. Our observations indicated that the participants were able to row in a satisfactory manner on the
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rowing ergometer after a 5-minute familiarization session. However, we suspect that, if we had allowed for more practice time (e.g., 10–15 minutes) before the test was administered, our participants would have likely displayed an even better rowing technique, which would have potentially allowed them to generate a higher peak power output. In addition, a prolonged familiarization session would have likely reduced the practice effects in the second trial, which probably contributed to statistically significant increases in mean from test 1 to test 2 for the low- and mediumresistance settings (Table 1). To avoid systematic bias at these resistance settings, we recommend that unskilled individuals perform 1 familiarization session before the actual measurement of whole-body peak power on a rowing ergometer. Interestingly, no systematic bias was observed at the highest resistance setting. At this point, we do not have a plausible explanation for this phenomenon. Validity refers to the extent to which an individual’s test performance reflects true or criterion performance (8) and, as such, it is a very important component in determining the utility of a test. To establish the validity of the peak power output test using a rowing ergometer, we calculated the correlation coefficients between the results of the newly constructed test and of the CMJ test, which had earlier proved to be a valid and highly reliable indicator of human muscle power output (14,15). We observed correlation coefficients to be fairly consistent across all 3 groups of participants and all 3 resistance levels, ranging between r = 0.70 and r = 0.78. In the literature, correlations between vertical jump performance (either mass-specific power output or jump height, representing a body size–independent measure of muscle power (15)) and standard anaerobic power tests, such as the Wingate cycling test, ranged between 0.51 and 0.87 (2,4,5,23). Although the observed coefficients indicate a very large positive relationship between the measures rendering the peak power output test on a rowing ergometer valid, we have to admit that our validation study had some limitations. First, due to low sample size per gender within each group, we combined the results from men and women in correlational analyses. This increased the variability of the data in both tests and, possibly, the strength of the relationships. Notably, correlational analysis performed separately on all men (n = 46) and all women (n = 41) yielded similar results (r = 0.69 and 0.73, respectively). Future studies should verify our results on larger samples of men and women. The second limitation is related to the obvious neuromechanical differences between jumping and rowing. For example, contrary to rowing motion that represents a whole-body activity, CMJ mainly involves the leg and trunk muscles. Furthermore, muscle contraction involved, and type of load (resistance) against which the required movement was performed also differs between CMJ and rowing. Specifically, the CMJ test involved the so-called stretch-shortening cycle muscle action, which enhances the ability of the neural and musculotendinous systems to VOLUME 29 | NUMBER 10 | OCTOBER 2015 |
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Power Output Test on a Rowing Ergometer produce maximal force in the shortest amount of time (16). During a rowing stroke, however, there is no stretchshortening cycle muscle action, and the legs are forcefully extended by means of concentric muscle action. In addition, although CMJ is a ballistic-type exercise with body mass acting as resistance, resistance on a rowing ergometer is based on wind turbulence generated by the bladed flywheel. Notwithstanding the discussed limitation of the CMJ as a validation test for rowing, it should be kept in mind that other standard short-term power output tests also have similar limitations (see Methods). By varying the resistance settings on the rowing ergometer, we attempted to identify the setting at which the highest peak power output was yielded in each group of participants. As evident in Table 2, peak power output continued to increase (p , 0.01) from low-, over medium-, to high-resistance settings in the group of participants with a low level of physical activity and in the group of physically active participants. This trend may indicate that the resistance at which the highest peak power output is produced in these groups of participants actually falls outside of the range of the resistance control dial on a Concept II rowing ergometer. Future studies should examine this possibility. On the contrary, medium-resistance setting yielded the highest peak power output values in the group of rowing athletes. Although ANOVA revealed no significant differences in peak power output across 3 resistance settings, magnitudes of these differences (i.e., 1.4–2.0%) could be practically relevant for rowing performance (8). Moreover, the difference in peak power output between moderate- and high-resistance setting is likely to be real (Table 2). The fact that power output tended to decrease after moderate-resistance setting in rowers is in contrast to a common observation that stronger individuals generally produce maximum power output at a higher absolute load than their weaker counterparts (for review, see Ref. (11)). Although we did not measure maximum strength of the tested groups of participants, accentuated differences in maximum power output between rowers and other groups of participants (Table 2) are unlikely related only to skill level or velocity component of power. Furthermore, it has been shown that rowers are among the strongest endurance athletes (13). We explain this finding by observing that the rowers in our sample normally set the resistance control dial during their training sessions at between 3 and 5 on the resistance control dial, corresponding to a drag factor in the range of ;110–125. The rowers stated that these resistance settings match the perceived feel of various boat types on the water. Consequently, the rowers’ adjustment to these resistance settings likely helped them to achieve the highest peak power output with the resistance control dial set at “5” on the resistance control dial, corresponding to a drag factor of ;125. In particular, it is likely that long-term exercising against a particular resistance induced load- (or velocity-) specific neuromuscular adaptations permitting rowers to yield maximum power
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output against a particular load (3,11). Further studies are needed to test this conjecture. An important issue that needs to be discussed is related to the use of power output provided by the Concept II rowing ergometer. Previous research clearly showed that the measurement of power output on the Concept II rowing ergometer is highly reliable (8,17). Furthermore, power output values obtained on the rowing ergometer proved to have high predictive validity (10) and discriminative ability (17). However, our observations indicate that the power output values displayed on the Concept II rowing ergometer underestimates the true power output by the factor of ;3. Thus, if the main aim is to measure true power output capabilities of humans, regular Concept II rowing ergometer should be equipped with additional hardware (i.e., force sensor and linear position transducer) and software equipment. In conclusion, the power output test on a Concept II rowing ergometer is a reliable and valid tool for assessing whole-body peak power output in untrained individuals and rowing athletes. To adjust the air resistance so that the highest peak power is generated, the adjustment mechanism should be set at “10” on the resistance control dial (i.e., it should be set at the highest adjustable resistance). If this test is applied to rowing athletes, the “5” setting seems optimal for generating the highest peak power output, probably, because it more accurately reflects the resistance against which the rowers typically row during their training sessions.
PRACTICAL APPLICATIONS Muscle power represents an essential component of both performance- and health-related physical fitness (3,18,19). The present findings suggest that rowing motion on a Concept II ergometer can be reliably used for whole-body peak power assessment in both skilled and unskilled adults of both sexes. Given that most training facilities use this ergometer, coaches and performance specialists could easily track the effects of various training and/or nutrition interventions on whole-body muscle power. When unskilled individuals use this test, 1 familiarization session before the actual measurement is recommended. Finally, practitioners should be aware that power output values displayed on the Concept II rowing ergometer markedly underestimate true power output generated by the individual. For this reason, measurement of individuals’ true maximal power output on a Concept II rowing ergometer requires additional hardware and software equipment.
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