Step test and physical working capacity in female volleyball players: the paradox of better performance in the older athletes

Test de Step y capacidad de trabajo en jugadoras de voleibol: la paradoja de un mejor rendimiento en las jugadoras mayores

Teste do degrau e capacidade de trabalho em jogadores de voleibol: o paradoxo de um desempenho melhor em jogadores mais velhos

 

 

Nikolaidis, P.T.^1,2, Afonso, J.³, Knechtle, B.⁴, Clemente-Suarez, V.J.⁵ y Torres-Luque, G.⁶

¹Department of Physical and Cultural Education, Hellenic Army Academy, Athens Greece;
²Exercise Physiology Laboratory, Nikaia, Greece;
³Faculty of Sport, University of Porto, Portugal;
⁴Instutute of Primary Care, University of Zurich, Switzerland;
⁵Department of Sport Science, European University of Madrid, Spain;
⁶Area of Corporal Express, Faculty of Humanities and Science Education, University of Jaen, Spain

Correspondence

 

 

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ABSTRACT

The aim of the present study was to compare two popular submaximal tests of aerobic capacity, the YMCA step test and the physical working capacity at heart rate (HR) 170 bpm test (P₁₇₀), in competitive female volleyball players. The participants (n = 152, age 12.78-41.67 yrs) were examined for anthropometric characteristics and performed the YMCA step test. Heart rate (HR) was recorded at the end of the test (Step_end) and at the end of the first minute of recovery (Step_rec). P₁₇₀ test was expressed in both absolute (P_170,abs, W) and relative values (P_170,rel, W.kg^-1). In addition, a sub-group (n = 14) was tested again one year later. The YMCA step test correlated largely (Step_rec) and very largely (Step_end) with P_170,rel (r = -0.58 and r = -0.76, p < 0.001, respectively), and P_170,abs (r = -0.54 and r = -0.68, p < 0.001, respectively). No correlation was observed among percentage changes in the tests of aerobic capacity over a year (p>0.05). Age correlated low-to-moderately with all indices of aerobic capacity (0.23 ≤ │ r │ ≤ 0.45, p<0.05), i.e. the older the age, the better the aerobic capacity. Based on the findings of the present study, it was concluded that the YMCA step test (especially the Step_end index) and P₁₇₀ might be used interchangeably by coaches and trainers to monitor aerobic capacity of female volleyball players. The paradoxically increase of aerobic capacity with age should be attributed to the assessment methods which were based on HR and to the decrease of maximal HR with age. Thus, these tests should be used only within a short range of age.

Key words: aerobic capacity, age groups, cycle ergometer, exercise mode, team sport.

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RESUMEN

El objetivo del presente estudio fue comparar dos pruebas submáximas de capacidad aeróbica, el YMCA step test y la prueba de capacidad de trabajo físico a 170 ppm (P₁₇₀) de frecuencia cardíaca (FC), en jugadoras de voleibol femenino. Se analizaron en 152 participantes variables antropométricas, el rendimiento, la frecuencia cardiaca final (Step_end) y la frecuencia cardiaca en el primer minuto de recuperación (Step_rec) en la prueba YMCA step test, la P₁₇₀ fue analizada expresando los resultados en valores absolutos (P_170,abs, W) y relativos (P_170,rel, W.kg^-1). Además, un subgrupo (n=14) fue analizado otra vez después de un año. Los resultados mostraron como el YMCA step test correlacionó altamente (Step_rec) y muy altamente (Step_end) con la P_{170 rel} (r = -0.58 and r = -0.76, p < 0.001, respectively), y con la P_170,abs (r = -0.54 and r = -0.68, p < 0.001, respectively). No se encontraron correlaciones entre los porcentajes de cambio en los test de capacidad aeróbica después de un año (p>0.05). La edad presentó una correlación baja a moderada con todos los índices de capacidad aeróbica (0.23 ≤ │ r │ ≤ 0.45, p<0.05), viendo como las mayores edades tenían una mejor capacidad aeróbica. Basándonos en estos resultados podemos concluir que la prueba YMCA step test (especialmente el parámetro Step_end) y la P₁₇₀ podrian ser utilizadas indistintamente por entrenadores y preparadores físicos para monitorizar la capacidad aeróbica de jugadoras de voleibol. El paradójico incremento de la capacidad aeróbica con la edad puede ser atribuido a los métodos de evaluación utilizados que están basados en la FC y al descenso de la FC máxima con la edad. Por lo tanto, estos test deberían ser utilizados solo con edades inferiores.

Palabras clave: capacidad aeróbica, grupos de edad, cicloergómetro, tipología de ejercicio, deporte de equipo.

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RESUMO

O objetivo deste estudo foi comparar dois testes de capacidade aeróbia submáximas, o teste do degrau YMCA ea capacidade de trabalho físico a 170 ppm (P170) da freqüêuência cardíaca (FC) em jogadores de voleibol das mulheres. Foram analisados 152 variáveis antropométricas envolvidos, o desempenho, a freqüência cardíaca final (Stepend) e freqüência cardíaca no primeiro minuto da recuperação (Steprec) no teste de etapa de teste YMCA, o P170 foi analisado expressando os resultados em valores absolutos (P170 , ABS, W) e relativo (P170, rel, W.kg^-1). Além disso, um subgrupo (n = 14) foi analisada outra vez depois de um ano. Os resultados mostraram que o passo de ensaio ACM altamente correlacionados (Steprec) e muito alta (Stepend) com P170 rel (r = -0,58 e r = -0,76, p <0,001, respectivamente), e o P170, ABS (R = -0,54 e r = -0,68, p <0,001, respectivamente). Não há correlação entre a variação percentual no teste de capacidade aeróbica após um ano (p> 0,05). Idade apresentou uma baixa a moderada correlação com todos os índices de capacidade aeróbica (0.23 ≤ │ r │ ≤ 0.45, p<0.05), observando as idades mais velhas tinham melhor capacidade aeróbica. Com base nestes resultados, podemos concluir que o teste de teste YMCA etapa (especialmente parâmetro Stepend) e P170 pode ser usado indiscriminadamente pelos treinadores e preparadores físicos para monitorar a capacidade aeróbia de atletas de voleibol. O aumento paradoxal na capacidade aeróbica com a idade pode ser atribuído aos métodos de avaliação utilizados, que são baseados no FC eo declínio da frequência cardíaca máxima com a idade. Portanto, estes testes devem ser usados apenas com idades mais jovens.

Palavras-chave: capacidade aeróbia, idade, cicloergômetro, tipo de exercício, esporte de equipe.

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Introduction

Volleyball is a team sport of intermittent high intensity nature, where a combination of physical characteristics, aerobic and anaerobic capacity is necessary in order to perform a sequence of well-coordinated high demanding activities. Although short-term muscle power output, expressed in actions of very short duration and maximal (e.g. jumping, hitting the ball), determines performance, a minimal level of aerobic capacity is necessary to cope with the demands of training and game-play (Sheppard, Gabbett, & Stanganelli, 2009). For instance, during game-play long rallies can last many seconds and fatigue accumulates especially in longer and/or more balanced matches, which emphasize the need of high aerobic capacity (Dávila-Romero, Hernández-Mocholí, & García-Hermoso, 2015; Laporta, Nikolaidis, Thomas, & Afonso, 2015). Therefore, assessing the aerobic capacity in this sport is an important task of coaches and fitness trainers. The aerobic capacity can be measured either by direct (e.g. a graded exercise test that elicits maximal oxygen uptake) or indirect methods (e.g. submaximal test on cycling ergometer) (Ekblom, 2014; Mahar, Guerieri, Hanna, & Kemble, 2011; Saint-Maurice, Welk, Laurson, & Brown, 2014). Compared to the former method that offers accuracy (which is necessary for sports that rely deeply on aerobic capacity such as the marathon) but demands very expensive equipment and specialized personnel, the latter can be used in larger numbers of athletes with only minimal requirements in equipment and expertise (especially in sports, where aerobic capacity is not the main factor of performance, e.g. volleyball).

One of the most widely used indirect tests of aerobic capacity is the Physical Working Capacity at heart rate 170 bpm (P₁₇₀), an official test of the Eurofit fitness battery, in which participants exercise on a cycle ergometer against given workloads (Bland, Pfeiffer, & Eisenmann, 2012). The heart rate (HR) responses to these workloads are recorded and P₁₇₀ is calculated from the HR-workload linear relationship as the workload corresponding to 170 bpm. P₁₇₀ is expressed in either absolute (P_170,abs, W) or relative to body mass values (P_170,rel, W.kg^-1). Aerobic capacity can be monitored by even more minimal equipment and expertise in the case of a step test, in which participants ascend and descend a step or box of a given height with a standard tempo dictated by a metronome. Among the various step test protocols, the YMCA step test has been used in dancers (Bronner & Rakov, 2014), basketball players (Nikolaidis, Calleja-González, & Padulo, 2014), non-athletes (Beutner et al., 2015; Jones, Coburn, Brown, & Judelson, 2012), and adults with intellectual disabilities (Pastula, Stopka, Delisle, & Hass, 2012).

Several studies have examined the relationship of the P₁₇₀ and YMCA test with performance in a VO2_max test enhancing our understanding of their validity and limitations (Boreham, Paliczka, & Nichols, 1990; Jankowski, Niedzielska, Brzezinski, & Drabik, 2015; Nikolaidis, 2011). However, whether the P₁₇₀ and YMCA step test can be used interchangeably has not been examined yet. It would be of great practical importance for coaches and trainers if a step test could be used instead of the P₁₇₀, offering them a much more handy and inexpensive solution. Therefore, the aim of the present study was to examine the relationship between the YMCA step test and P₁₇₀ in competitive female volleyball players.

 

Methods

Participants

The present investigation was conducted in two parts: the first was a cross-sectional study (n = 152, age 20.8±6.0 yrs, range 12.8-41.7 yrs, Table 1), and the second was a longitudinal study, in which a sub-group (n = 14, age 21.2±5.9 yrs, Table 2) of the first study was examined again for the same parameters exactly one year later. The first study was conducted on the preparation period of the 2014-2015 season, whereas the second study took place on the corresponding period of the 2015-2016 season. The adult participants (≥18 yrs age group, n = 87, age 24.8±5.4 yrs, range 18.2-41.7 yrs) competed with their teams in the top three national leagues of Greece and the adolescents (<18 yrs age group, n = 65, age 16.0±1.0 yrs, range 12.8-18.0 yrs) participated in the official tournaments of their age groups. The local institutional review board approved this study, which was conducted according to the ethical standards of Declaration of Helsinki of the World Medical Association in 1964 as it was modified in 2013. The participants provided informed consent.

 

 

 

Devices

An electronic body mass scale (HD-351 Tanita, Illinois, USA), a portable stadiometer (SECA, Leicester, UK) and a skinfold caliper (Harpenden, West Sussex, UK) were used to measure anthropometric characteristics (body mass, stature and skinfolds, respectively). Team2 Pro (Polar Electro Oy, Kempele, Finland) was used to record HR during all testing session. The P₁₇₀ test was performed on a cycle ergometer (828 Ergomedic, Monark, Sweden). A box of 30 cm height was used in the YMCA step test.

Procedures

Before starting the testing session, the participants were examined for anthropometric characteristics. Body mass and stature were measured with participants being barefoot and in minimal clothing. These measurements were used to calculate Body mass index (BMI) as the quotient of body mass (kg) to stature squared (m²). Body fat percentage (BF) was calculated from the sum of 10 skinfolds (Parizkova, 1978). Thereafter, the participants performed the P₁₇₀ and YMCA step test in a counterbalanced order, separated by a 10 min break. In the P₁₇₀ test, saddle height was adjusted to each participant's satisfaction and toe clips with straps were used to prevent the feet from slipping off the pedals. The participants were instructed to pedal with a steady cadence of 60 revolutions per minute, which was given by both audio (metronome set at 60 beats per minute) and visual means (ergometer's screen showing pedaling cadence). This test lasted 9 min including three 3 min stages, each against incremental braking force in order to elicit HR between 120 and 170 beats per minute (Bland et al., 2012). Between the two tests of aerobic capacity a break of passive recovery was provided. In the YMCA step test, the participants were instructed to ascend and descend a box for 3 min using a 24 ascent·min^-1 cadence (Beutner et al., 2015). Two indices of this test were recorded: Step_end, the HR in the end of the test, and Step_rec, the HR in the end of the first minute of recovery. In the P₁₇₀ test, the higher the P_170,abs or P_170,rel, the higher the aerobic capacity, whereas in the YMCA step test, the lower the Step_end or Step_rec, the higher the aerobic capacity.

The IBM SPSS v.20.0 (SPSS, Chicago, USA) software was used to perform the statistical analysis. Data were expressed as mean and standard deviations of the mean (SD). The differences between adolescent and adult participants were tested by an independent t-test, whereas a paired samples t-test compared the scores of the participants who were evaluated twice over a year. Mean differences together with 95% confidence intervals (CI) were calculated. The effect size for statistical differences in the t-test was interpreted by Cohen's d classified as d ≤ 0.2, trivial; 0.2 < d ≤ 0.6, small; 0.6 < d ≤ 1.2, moderate; 1.2 < d ≤ 2.0, large; and d > 2.0, very large (Hopkins, Marshall, Batterham, & Hanin, 2009). Pearson correlation coefficient r examined the relationships among anthropometric characteristics and aerobic capacity tests, as well as the relationship among percentage changes in these tests over a year. To interpret the magnitude of correlations the following criteria were adopted: r≤ 0.1, trivial; 0.1 < r≤ 0.3, small; 0.3 < r≤ 0.5, moderate; 0.5 < r≤ 0.7, large; 0.7 < r≤ 0.9, very large; and r> 0.9, almost perfect (Hopkins et al., 2009). The level of significance was set at α=0.05.

 

Results

The anthropometric characteristics of participants can be found in Table 1. Differences among age groups were shown for body mass and BF. The older age group (≥18 yrs) was heavier, but with less BF than the younger (<18 yrs) group (p < 0.05). These differences had small magnitude. The changes in anthropometric characteristics over a year can be seen in Table 2. Statistical differences were found for body mass and BF (p < 0.05). The magnitude of these changes was small.

The results of the tests of the aerobic capacity for the cross-sectional study can be found in Table 3. The age groups differed for both tests and all indices (p < 0.05). In these tests, adult scored better than adolescent volleyball players. These differences were of moderate magnitude for Step_end, P_170,abs and P_170,rel, and small for Step_rec. The changes in these tests over a year can be seen in Table 4. Except Step_end (improvement of small magnitude, p < 0.01), no difference was observed the tests over a year.

 

 

 

The correlations among anthropometric characteristics and indices of aerobic capacity can be seen in Table 5. All indices of aerobic capacity correlated with age in the older group and in the total sample (p < 0.05), i.e. the older the age, the better the performance. P_170,rel in the total sample and step test indices in the adult group and in the total sample correlated negatively with BF (p < 0.05), i.e. the higher the BF, the lower the performance. However, body mass, height and BMI correlated only with P_170,abs (p < 0.05).

 

 

With regards to the correlations between the two tests of aerobic capacity (Table 6), the YMCA step test correlated largely (Step_rec) and very largely (Step_end) with P_170,rel, and with large correlations with P_170,abs (p < 0.001). Regression equations between step test and P₁₇₀ indices can be seen in Figure 1. The standard error of estimate of Step_rec was higher than Step_end for both P_170,abs and P_170,rel.

 

 

 

Discussion

To study the relationship between the YMCA step test and the P170 test, and the variation of this relationship by age, female adolescent and adult volleyball players performed these two tests. The main findings of the present study were that (a) the YMCA step test correlated largely (Step_rec) and very largely (Step_end) with P₁₇₀, (b) the magnitude of these correlations was higher in P_170,rel than in P_170,abs, (c) these correlations were larger in adult than in adolescent volleyball players, and (d) paradoxically, a trend of increase in aerobic capacity with age in the adult group was observed.

The larger correlation of P₁₇₀ with Step_end than with Step_rec should be expected, because P₁₇₀ and Step_end reflected HR responses to exercise, whereas Step_rec represented the function of recovery. The larger correlations of the YMCA step test with P_170,rel than with P_170,abs might be explained taking into account the role of body mass. In the cycle ergometer, a large body mass was compensated by the fact that the test was conducted with the participant supported by the seat; on the other hand, in the step test, the body mass was an important factor that the participant had to carry in the step (Saint-Maurice et al., 2014). Hence, when the P170 was expressed in relative values was logical that the correlation should be larger. As it was shown in the correlation analysis between anthropometric characteristics and aerobic capacity, there was a moderate to large correlation between body mass and P_170,abs, i.e. the higher the body mass, the higher the P_170,abs.

The performance in the aerobic tests low to moderately correlated with age, i.e. the older the age, the better the performance, whereas no correlation was observed in the adolescent group. The finding in the younger group was in agreement with the existing literature, where aerobic capacity remained relatively stable from 12 to 18 yrs in females (Shvartz & Reibold, 1990; Nikolaidis et al., 2012). However, the finding in the older group was not in line with the existing literature (Fitzgerald, Tanaka, Tran, & Seals, 1997; Grigaliuniene et al., 2013; Shvartz & Reibold, 1990), which has clearly demonstrated that aerobic capacity declined after the age of 18 years in women (independently of the training status). For example, a meta-analysis of sedentary, active and endurance-trained female adults showed that maximal aerobic capacity declined with increasing age (Fitzgerald et al., 1997). Compared to a 20-29 yrs age group, women of 30-39 yrs showed lower VO_2max and HR_max (Grigaliuniene et al., 2013). A review on aerobic capacity norms showed that females had VO_2max 1.8, 2.2, 1.8 L.min^-1 at the age of 12, 18 and 30 yrs, respectively (Shvartz & Reibold, 1990).

The significant correlation of aerobic capacity with age in the adults might be interpreted in three ways. First, a better aerobic capacity in the older group might result from the long-term training process in volleyball, where athletes with lower capacity would not advance. Second, both tests used in the present study were based on HR responses to a given submaximal load. A negative effect of age on maximal HR (HR_max) has been well-established previously, and consequently HR_max could be predicted by age-based equations (e.g. Tanaka's 208-0.7x-age). The adolescent and adult groups differed by ~9 yrs and had predicted HR_max 197 and 191 bpm, respectively. Consequently, the HR responses to the 3-min step test were quite similar when being expressed as %HR_max (80 versus 78%, respectively). Even if the 3-min step test elicited different HR responses, it caused similar relative physiological load in both age groups. The third one explained this correlation between age and aerobic capacity since a correct training, based on long distance and low intensity or short distance and high intensity, could revert the effects traditionally associated with age, according to actually studies conducted not only in <30 years athletes, but also in adults and elderly people (Broman, Quintana, Lindberg, Jansson, & Kaijser, 2006; Clemente-Suarez, 2014). This might be a reasonable explanation of the paradox of better aerobic capacity in the older volleyball players.

A limitation of the present study was that its longitudinal part did not include more testing in more periods of the season (e.g. beginning versus end of preparation period); thus, there were very small changes in the two aerobic capacity tests and, consequently, this might be a reason that the correlation analysis could not identify any relationship between the two tests over time. On the other hand, strength of this study was that it included one of the largest samples of female volleyball players ever studied, which allowed drawing inferences for other groups of volleyball players, too. Moreover, these findings might be of great practical value for volleyball coaches and trainers in the context of monitoring aerobic capacity of their athletes.

Practical Applications

Specific evaluation is very important for the coaches and trainers. This study is of great practical importance for coaches and trainers a step test could be used instead of the P170, offering them a much more handy and inexpensive solution. Based on the findings of the present study, it was concluded that the YMCA step test (especially the Step_end index) and P₁₇₀ might be used interchangeably by coaches and trainers to monitor aerobic capacity of female volleyball players.

 

Conclusions

Based on the findings of the present study, it was concluded that the YMCA step test and P₁₇₀ might be used interchangeably by coaches and athletes to monitor aerobic capacity of female volleyball players. Instead of Step_rec, Step_end should be preferred as a better proxy for P₁₇₀. Since both tests relied on HR response to exercise - and HR was influenced by age, they should be used to monitor aerobic capacity only within short ranges of age.

 

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Correspondence:
Pantelis Nikolaidis.
Thermopylon 7,
Nikaia 18450 (Greece).
E-mail: pademil@hotmail.com

Recibido: 05/05/2015
Aceptado: 15/02/2016