COMPARISON OF AEROBIC PERFORMANCE INDICATORS OF SOCCER AND FUTSAL ATHLETES

COMPARAÇÃO DE INDICADORES DE DESEMPENHO AERÓBICO DE ATLETAS DE FUTEBOL E FUTSAL

COMPARACIÓN DE INDICADORES DE DESEMPEÑO AERÓBICO DE ATLETAS DE FÚTBOL Y FUTSAL

ABSTRACT

Soccer and futsal have similar technical movements that are used within different spatial dimensions and game dynamics. The possible physiological differences between players of each sport were unknown. The main purpose of this study was to compare the maximum oxygen uptake (VO₂max) and ventilatory thresholds (VT) of soccer and futsal players. VO₂max and VT of 32 athletes (soccer: n = 15; futsal: n = 17) were obtained by ergospirometry in a progressive treadmill test. VO₂max was similar between groups. VT occurred later and at higher running speeds in the soccer players. The similarities found in VO₂max may be related to the fact that the evaluations were carried out in the pre-season. The fact that the VT was reached later in the soccer players suggests a longer capacity for aerobic exercise and greater resistance to lactate production. Moreover, soccer players appear to be conditioned to withstand increased running times and speeds, until exhaustion. Players of both sports reached the second VT at similar intensities, suggesting no prevalence of anaerobic metabolism. Soccer and futsal players have similar VO₂max, but their VTs occur at different times, and at different running speeds. Level of Evidence III; Cross-sectional study.

Keywords:
Soccer; Oxygen consumption; Athletes

RESUMO

O futebol e o futsal têm movimentos técnicos semelhantes que são utilizados em distintas dimensões espaciais e dinâmicas de jogo. As possíveis diferenças fisiológicas entre as modalidades não foram esclarecidas. O objetivo do presente estudo foi comparar o consumo máximo de oxigênio (VO_2máx) e os limiares ventilatórios (LV) de atletas de futebol e futsal. O VO_2máx e os LV de 32 atletas (futebol: n = 15; futsal: n = 17) foram obtidos por ergoespirometria em teste progressivo de esteira. O VO_2máx foi semelhante entre grupos. Os LV ocorreram mais tardiamente e em maiores velocidades nos atletas de futebol. A semelhança encontrada nos valores de VO_2máx pode estar relacionada com as avaliações terem sido realizadas em pré-temporada. A obtenção tardia dos LV em atletas de futebol sugere maior permanência em exercício aeróbico e maior resistência à produção de lactato. Além disso, parecem estar condicionados ao fato de suportarem maiores tempos e velocidades de corrida até chegarem à exaustão. Entretanto, ambas as modalidades atingiram o segundo LV em intensidades semelhantes, sugerindo não haver prevalência do metabolismo anaeróbico. Atletas de futebol e futsal apresentam VO_2máx similares, embora os LV ocorram em momentos distintos e com diferentes velocidades de corrida. Nível de evidência III; Estudo transversal comparativo.

Descritores:
Futebol; Consumo de oxigênio; Atletas

RESUMEN

El fútbol y el futsal tienen movimientos técnicos semejantes que son usados en distintas dimensiones espaciales y dinámicas de juego. Las posibles diferencias fisiológicas entre las modalidades no fueron esclarecidas. El objetivo del presente estudio fue comparar el consumo máximo de oxígeno (VO₂máx) y los umbrales ventilatorios (UV) de atletas de fútbol y futsal. El VO₂máx y los UV de 32 atletas (fútbol: n = 15; futsal: n = 17) fueron obtenidos por ergoespirometría en test progresivo de cinta. El VO₂máx fue semejante entre grupos. Los UV ocurrieron más tardíamente y en mayores velocidades en los atletas de fútbol. La semejanza encontrada en los valores de VO₂máx puede estar relacionada con que las evaluaciones hayan sido realizadas en pretemporada. La obtención tardía de los UV en atletas de fútbol sugiere mayor permanencia en ejercicio aeróbico y mayor resistencia a la producción de lactato. Además, parecen estar condicionados al hecho de soportar mayores tiempos y velocidades de carrera hasta llegar al agotamiento. Entretanto, ambas modalidades alcanzaron el segundo UV en intensidades semejantes, sugiriendo no haber prevalencia del metabolismo anaeróbico. Atletas de fútbol y futsal presentan VO₂máx similares, aunque los UV ocurran en momentos distintos y con diferentes velocidades de carrera. Nivel de evidencia III; Estudio transversal comparativo.

Descriptores:
Fútbol; Consumo de oxígeno; Atletas

INTRODUCTION

Soccer is a field sport with various movements and movement patterns required from players (e.g. shorts and long sprints, walking and running slowly, accelerations with rapid decelerations, changes in direction, jumps, kicks, and confrontations).^1,2 Futsal is similar to soccer, but it is played on a smaller court, with fewer players, uses a smaller ball, and allows for constant and unlimited substitutions.^3–6 Futsal is a dynamic and intense sport that requires many movements within short periods.^3,5,7

Various studies have compared the physiological characteristics of soccer and futsal players.^5,7–11 Maximum oxygen uptake (VO₂max) and ventilatory threshold (VT) are two characteristics that are commonly used to measure athletes' fitness. VO₂max is an indicator of the highest oxygen uptake (VO₂) per unit of time that an individual can capture, transport and use at the cellular level.⁸ VT is an indicator of lactate production and includes a first and second threshold.¹² VO₂max is a determinant factor for aerobic capacity¹³ and is considered the gold standard for assessing aerobic fitness. VO₂max seems to be a determinant in soccer performance,^13,14 but not as much in futsal performance.⁵ The literature contains contradictory data, where studies have found higher VO₂max in soccer,⁷ or futsal players,⁵ and have also observed similarities.^8,10 These different outcomes can be attributed to factors ranging from different evaluation periods during the season, level of competitiveness and evaluation protocols.

VT is a measure of endurance performance. The first VT threshold (VT₁) corresponds to the start of blood lactate accumulation, and the second threshold (VT₂) to the moment when lactate production exceeds its removal.⁹ Studies comparing VTs of soccer and futsal players^5,8–10 have related VT to VO₂ at the time of VT₂,^5,9 and the percentage of VO₂max during VT₂ (%VO₂maxVT₂).^9,15 Soccer players reached %VO₂maxVT₂ between 76.6 and 90.3% and futsal players between 65 and 77%,⁹ demonstrating that VT₂ occurred at different exercise intensities.¹⁰ The percentage of VO₂max during VT₁ (%VO₂maxVT₁) is rarely reported in the literature^16,17 even though it is an indicator of aerobic metabolism¹⁶ that marks the beginning of lactate accumulation.¹⁸ Running speed during each VT is also a parameter of exercise intensity^9,18, and when running speed is associated with VO₂max and VT it can provide more information than isolated cardiorespiratory variables.^11,15,19 Studies evaluating running speed during VT₁ (speedVT₁),⁹ and VT₂ (speedVT₂)^5,8,9 have found contradictory results, where: speedVT₁ was superior in futsal players;⁹ speedVT₂ was superior in soccer players, and;⁸ speedVT₂ was similar in soccer and futsal players.⁹ These contradictory outcomes could result from a lack of control in training stage between soccer and futsal players. This study aimed to compare the VO₂max and VT of soccer and futsal players at the same training stage during the start of the preseason. We hypothesized that: 1) soccer players would have higher VO₂max than futsal players;⁷ and 2) VT₁ and VT₂ would occur earlier in futsal players than soccer players.⁹

MATERIALS AND METHODS

Participants

This study was approved by the institutional Research Ethics Committee of the University of Santa Cruz do Sul, RS, Brazil (number 1.514.711). All participants read and signed an informed consent form.

Study participants were State level male soccer and futsal players who met the inclusion criteria: a) aged 18 to 30 years old; b) no musculoskeletal injuries; c) no respiratory disorders; and d) no heart disease. Individuals who did not reach VT₂ during testing and those who had difficulties understanding the experimental protocol were excluded from the study. Thirty-two athletes (soccer: n = 15; futsal: n = 17) participated in the study.

The evaluation took place preseason, prior to any soccer or futsal training. During the evaluation period, soccer and futsal players began their preparation to compete in the State championships.

To characterize athletes, body mass and height were measured. Measurements followed Heyward's guidelines using a beam scale (Welmy R110; Welmy SA, Santa Bárbara do Oeste, Brazil).²⁰

Assessment of performance indicators

Cardiorespiratory parameters were obtained by ergospirometry during a maximal effort test on a treadmill (Super ATL, Inbramed Ltda., Porto Alegre, RS, Brazil). The Bruce ramp protocol was used, which consists of seven three-minute stages. The starting speed and inclination were 2.7 km/h and 10°, respectively. Each progressive stage involved an increase in speed and inclination of 1.6 km/h and 2°.^21,22 Respiratory gases were measured every 20 seconds by a gas analyzer (VO2000, Aerosport, Medgraphics, St. Paul, Minnesota, USA), which was calibrated before the start of each test within a temperature-controlled environment (20-22°C). Assessments were performed during the day, with all subjects in a resting state (sitting for five minutes) until the time of the test. The test duration was determined by the athletes' voluntary exhaustion; when the athletes reached their effort limit, the test was immediately interrupted, and the recovery phase began [three minutes of walking on the treadmill at 2.7 km/h without any inclination (0°)].

VO₂max was determined by the VO₂ peak reached during the maximal effort test.²³ It was captured in absolute and relative values, but only relative values were reported. VTs were identified by three experienced evaluators using the visual-graphic method, which consists of observing the behaviour of the VO₂ curve (oxygen consumption over time) and the production of carbon dioxide (VCO₂) during progressive effort. VT₁ was identified when the VCO₂ increased disproportionately to VO₂ (i.e. loss of parallelism), while VT₂ was identified at the time of respiratory compensation or during the disproportionate increase in ventilation compared to VCO₂.^17,23 For VT₁ or VT₂, when the three evaluators identified identical values, that value was adopted. In the case of divergences between evaluators, the median result was chosen.

Each VT was calculated relative to VO₂max (%VO₂maxVT₁; %VO₂maxVT₂), acquisition time of VT (in min),^8,15,24 and running speed on the treadmill (speedVT₁; speedVT₂).^9,24

Statistical analysis

Descriptive analyses (mean and standard deviation) were performed. The normality of the data was verified by the Shapiro-Wilk test. Between-group comparisons were performed using Student's t-test for independent samples (parametric data), or the Mann-Whitney U test (non-parametric data). All statistical tests were performed using SPSS software (v. 23.0; IBM Corporation, Armonk, New York, NY, USA), with α=0.05.

RESULTS

The characterization of the players is shown in Table 1. Regarding positions, soccer players included a goalkeeper, a full-back, four defenders, four defensive midfielders, three midfielders, and two forwards. Futsal players included two goalkeepers, four defenders, nine wingers, and two pivots. The groups were similar in terms of age and body mass; however, soccer players were taller.

Table 1
Characterization of groups of players.

	Soccer	Futsal	p
Age (years)	25.60±3.18	26.82±2.92	0.266
Mass (kg)	79.32±7.35	75.76±8.10	0.206
Height (m)	1.77±0.06	1.72±0.05	0.022*

• Values expressed as mean and standard deviation (±);
• ^*
  = statistically significant differences between groups (p<0.05).

No differences were found in VO₂max and %VO₂maxVT₂ between groups but soccer players had higher %VO₂maxVT₁, VT₁ and VT₂. In addition, futsal players reached both VTs at lower speeds (Table 2).

Table 2
Cardiorespiratory variables of soccer and futsal players.

	Soccer	Futsal	p
VO2max (ml·kg-1·min-1)	39.80±6.86	36.97±5,84	0,219
VO2maxVT1 (%)	62.81±15.29	50.68±10.64	0.013*
VT1 (min)	9.15±2.08	5.50±1.02	0.000*
SpeedVT1 (km/h)	6.44±1.00	4.49±0.68	0.000*
VO2maxVT2 (%)	91.65±7.29	86.19±11.72	0.130
VT2 (min)	15.10±2.61	12.02±1.42	0.000*
SpeedVT2 (km/h)	8.42±0.73	7.31±0.81	0.001*

• Values expressed as mean and standard deviation (±); VO₂max = maximal oxygen uptake; %VO₂maxVT_{1 =} percentage of VO₂max at first ventilatory threshold; VT₁ = first ventilatory threshold; speedVT₁ = speed during first VT; %VO₂maxVT_{2 =} percentage of VO₂max at second ventilatory threshold; VT₂ = second ventilatory threshold; speedVT₂ = speed during second VT.
• ^*
  = statistically significant differences between groups (p≤0.05).

DISCUSSION

This study aimed to compare aerobic performance indicators between soccer and futsal players. No differences were found in VO₂max and %VO₂maxVT₂ between groups. Percent VO₂maxVT₁ was lower in futsal players, and their VT occurred sooner and at lower speeds than in soccer players.

VO₂max represents the maximal capacity of oxygen consumption and reflects level of fitness. We found no differences in VO₂max between soccer and futsal players. These results agree with previous studies that controlled for stage of training.^8–10 Soccer and futsal players may have similar VO₂max levels due to the intermittent high-intensity nature of their sports.⁴ Contradictory values of VO₂max were identified between soccer and futsal players in studies that did not control for stage of training. Karimi, Hojjati and Shamsi⁷ found higher VO₂max values in soccer players (57.42 ml·kg-¹·min-¹) than futsal players (52.77 ml·kg-¹·min-¹). According to the authors, this suggests an aerobic predominance in soccer, where the aerobic system is the main source of energy (70 to 90%) during a match/ training.^5,7,10,25 VO₂max is linked to the distance covered during a match; thus, soccer players may have better endurance, withstanding longer periods of exercise until exhaustion.⁸ On the other hand, Nunes et al.⁵ found a higher VO₂max in futsal players (62.5 ml·kg-¹·min-¹) than in soccer players (52.1 ml·kg-¹·min-¹). These authors attributed their results to the different training methods, levels of competitiveness and number of competitions between players. Therefore, the level of competitiveness of the teams may have influenced the results, as the futsal team in their study competed nationally while the soccer team competed at the state level. Since VO₂max may vary during the season (3-7% lower at the beginning of the season than the end),¹³ it is important to consider evaluation period, periodization of training, and level of competitiveness of players when different sports are compared.

VT₁ refers to the beginning of lactate accumulation during physical effort.¹⁸ In our study, futsal players reached VT₁ at lower percentages of VO₂max, and it occurred earlier and at lower speeds than in soccer players, suggesting earlier lactate production in futsal players. This may result from greater participation of anaerobic glycolytic metabolism in futsal players, while aerobic metabolism is still their main source of energy.¹⁶ Despite this, VT₁, which represents intensity of effort relative to VO₂max, was lower in futsal than in soccer players and futsal players had a longer interval between VT₁ and VT₂. According to Wilke et al.,¹⁷ intensity is divided into three zones: below VT₁ (low intensity), between VT₁ and VT₂ (moderate intensity), and above VT₂ (high intensity). It is reported that futsal players expend 73% of a training session below VT₁, 20% between the VT₁ and VT₂ and 7% above VT₂.¹⁷, while soccer players cover approximately 11 km in a match, with 3% and 5% of a training session spent sprinting and running at high-intensity effort, respectively.²⁶ Therefore, it is expected that futsal players have higher speeds during VT, since speedVT is highly correlated to the ability to perform repeated high-intensity sprints over time.²⁴ Contrary to our results, Ribeiro et al.⁹ observed a higher speedVT₁ in futsal players (13.3 km/h) than soccer players (11.0 km/h); however, this study did not control for preseason period (initial and final). Ribeiro et al.⁹ also adopted a more intense ramp protocol with an increase in speed of 1 km/h every minute, where testing lasted between 8-12 minutes, while we adopted a longer protocol (i.e. Bruce protocol) with increases in speed and inclination of 1.6 km/h and 2° at each 3-min stage, lasting up to 21 minutes.

VT₂ represents the respiratory compensation point.¹⁸ We found no differences in %VO₂maxVT₂ between soccer and futsal players. This is in agreement with the results of Baroni et al.,⁸ who observed %VO₂maxVT₂ at similar intensities (soccer = 87.89%; futsal = 88.29%). Nunes et al.⁵ found higher %VO₂maxVT₂ in futsal players (futsal = 93.9%; soccer = 76%), who reached VT₂ at higher intensities than soccer players. Our results may have been different from Nunes et al.⁵ because our evaluations were performed at the beginning of the preseason, while Nunes et al.⁵ did not mention the phase of the preseason in which players were evaluated. In our study, VT₂ was reached earlier (less time) in futsal than soccer players. Leal Junior et al.,¹⁰ also found that futsal players reached VT₂ earlier (11.4 min) than soccer players (14.0 min), suggesting that soccer players have a greater aerobic capacity. Like Baroni et al.,⁸ we found that speedVT₂ was greater in soccer players than futsal players. Soccer players reached both VTs at higher speeds (equivalent to time/test stage), where VO₂ increases as running speed increases,²⁷ suggesting that soccer players can withstand progressive effort for longer periods until exhaustion.⁸

Our study had some limitations. Laboratory effort protocols, such as the one used in this study, are not very functional for soccer and futsal, while field tests have good applicability.^28,29 However, the procedures used in this study can be performed with athletes to assess basic physiological parameters (e.g. VO₂max and VT), which assist in building highly specific training programs.^22,29 Participants in our study were not stratified by position, which could have minimized intragroup variation as there are different mechanical and physiological demands for each position.^8,18,30 However, the number of players evaluated did not allow for such stratification. To control these limitations, pre-training and post-training evaluations could be performed, and training routines and game calendars could be monitored.¹⁸ This would allow us to identify adaptations to physiological parameters caused by training.³¹ As well, the inclusion of other physiological markers such as blood lactate,^4,15,32 heart rate,^2,5 and subjective perception of effort,^31,33 could provide additional information about the demands of soccer and futsal and the physiological profiles of players.

CONCLUSION

In the preseason phase of the competitive calendar of soccer and futsal, male players have similar VO₂max's and reach their VT at different times and speeds. Different levels of physical effort and physiological adaptations exist for each sport, indicating that training methods should be designed with each sport's specificity in mind.

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Publication Dates

• Publication in this collection
  11 Dec 2020
• Date of issue
  Nov-Dec 2020

History

• Received
  22 June 2019
• Accepted
  19 Aug 2020