##plugins.themes.bootstrap3.article.main##

Rowing, characterized as a “velocity-centric sport,” demands high physical and physiological performance. Cardiorespiratory endurance, an integral component of physical fitness, plays a vital role in rowing performance. Optimal physical fitness is essential for injury prevention and success in international competitions. Cardiopulmonary exercise testing (CPET) is the gold standard for assessing maximal oxygen uptake (VO2 max), a crucial indicator of cardiopulmonary endurance. The considerable expense and specialized expertise required for CPET have prompted the utilization of field tests, such as the beep test. The current study aims to validate the accuracy of the beep test in measuring VO2 max uptake as the gold standard. The present cross-sectional observational study involved 16 participants from the national rowing pool of Sri Lanka (11 males, 5 females). The study adhered to the Bruce protocol for implementing CPET to measure VO2 max. Concurrently, the standardized beep test, encompassing 21 progressively challenging levels, was administered to assess the VO2 max of participants. The number of shuttles completed during the beep test underwent meticulous conversion into corresponding VO2 max values, facilitating a comparative analysis with the VO2 max values derived from CPET. Among the key findings, the CPET among Sri Lankan rowers, male rowers exhibited statistically significant disparities across several vital physiological parameters, including VO2 max, VO2 max at anaerobic threshold (VO2 max AT), maximum heart rate (HR max), and minute ventilation (VE), against their female counterparts. A statistically significant and positive correlation was discerned among female rowers between the VO2 max values obtained through the gold standard CPET and those derived from the beep test. However, a consistent trend emerged, revealing that the beep test consistently overestimated VO2 max in both male and female rowers compared to the gold standard CPET method. The study underscores the importance of considering population-specific factors and advocates for developing refined equations to enhance the accuracy of field tests in predicting cardiopulmonary endurance.

Introduction

Rowing, a “velocity-centric sport,” is known for demanding physical and physiological requirements. Rower performance relies on various factors, including cardiovascular endurance, motor coordination, technical skills, and aerobic and anaerobic fitness. Achieving optimal physical fitness is crucial for injury prevention and success in international competitions (DeBlauwet al., 2023).

Cardiorespiratory endurance, a key component of health-related physical fitness (Chenget al., 2019), entails the efficient supply of oxygen to skeletal muscles during physical activity (Raghuveeret al., 2020). Endurance training is vital for athletes across various sports, not just long-distance disciplines. It aims to enhance parameters like VO2 max, which reflects maximal oxygen consumption during exercise (Joyner & Coyle, 2008).

Cardiorespiratory endurance is typically assessed using gas-analyzed and non-gas-analyzed tests (Raghuveeret al., 2020), with direct measurement of VO2 max considered the gold standard (Dalui & Bandyopadhyay, 2017). However, this method requires specialized facilities and can be resource-intensive.

In contrast, the beep test offers a cost-effective and scalable alternative. It can be administered to large groups simultaneously. This study aims to validate the beep test for assessing cardiorespiratory endurance by comparing it to the gold-standard Cardiopulmonary Exercise Test (CPET). The research focuses on evaluating the predictive accuracy of the beep test formula for assessing cardiovascular endurance.

Methodology

Participants

This study employed a comprehensive total population sampling approach, incorporating the complete cohort of male (n = 11) and female (n = 5) rowing athletes within the national pool of Sri Lanka. Exclusion criteria were rigorously applied to non-consenting participants, those with recent musculoskeletal, neurological, or other injuries within the prior month, athletes who had undergone surgery in the preceding six months, and individuals medically contraindicated for vigorous physical activities. Additionally, participants with documented cardiorespiratory conditions, confirmed by medical diagnoses, such as exercise-induced asthma and asthmatic attacks, were excluded. Data collection spanned from July 2021 to March 2022, encompassing a comprehensive examination of the selected athletes.

Ethical Considerations

This study meticulously obtained ethical clearance from the Ethical Review Committee of the Faculty of Medicine at General Sir John Kotelawala Defense University (RP/S/2021/33). Formal permissions were also diligently secured from the Institute of Sports Medicine under the Ministry of Sports and the Rowing Council of Sri Lanka, ensuring strict adherence to ethical and regulatory standards.

Procedure

The CPET Measures

Before the fitness assessments, verbal and written consent was obtained from the participants. All CPETs were conducted in the morning and in a temperature and humidity-controlled environment. Bruce protocol was used to carry out the CPET (Linderet al., 2006). Participants were instructed to adhere to specific guidelines, including abstaining from exercise, alcohol, and supplementation for 24 hours before testing. Additionally, they were required to fast for two hours before testing. Pre-CPET medical assessments were carried out by a qualified medical officer, followed by stretching sessions to prevent injuries. Resting blood pressure and blood oxygen saturation were checked to ensure eligibility. Participants wore Heart Rate monitors throughout the procedure. The CPET started with a warm-up on the rowing ergometer, followed by the attachment of electrodes to monitor cardiac activity. Participant demographics were recorded. CPET masks were fitted, and participants were briefed on the protocol. Oxygen consumption and heart rate were continuously monitored. The sports physician engaged in real-time ECG oversight for arrhythmias or anomalies, contemplating the termination of CPET upon detecting any abnormal indication. The ergometer’s inclination increased gradually to introduce resistance.

Participants were encouraged to perform at their maximum, aiming for maximal oxygen consumption (VO2 max). Breath-by-breath data analysis determined an experienced physiologist identified VO2 max and the anaerobic threshold. After the test, participants cooled down, and post-test measurements were taken. ECG electrodes were removed, and participants were instructed to rest. CPET reports were provided. VO2 max was measured using the Medgraphics Ultima CardiO2 sensor and the Concept II Model C rowing ergometer software.

Administering the Beep Test

The beep test was conducted in the Institute of Sports Medicine indoor gymnasium, concurrent with the preceding day’s CPET. All Beep tests were conducted in the morning, and the temperature was meticulously monitored during testing. Participants received detailed instructions and a practical demonstration from the same investigator.

The beep test consists of 21 levels, each with a specific number of shuttles. Participants ran back and forth on a 20-meter distance on a cemented floor, following a pre-recorded audio track of beeping signals. The number of shuttles completed by each participant was recorded until they couldn’t maintain the required pace.

The test started at a slower speed and progressively increased with each beep. Up to five participants could perform the test together and were encouraged to push themselves to their limits. The total number of shuttles completed was noted, and it was then converted into a VO2 max equivalent score using a specific mathematical equation provided by Purbaet al. (2021), which is provided in Eq. (1):

(1)CapVO2max=18.043461+(0.3689295×TS)+(−0.000349×TS×TS)where TS refers to the total number of shuttles.

Statistical Analysis

Data analysis was performed using IBM Statistical Package for Social Science (SPSS) version 23, and the normality of the data was assessed using the Kolmogorov-Smirnov test.

Results

The anthropometric data obtained for both male and female rowers are given in Table I.

BMI (Kgm−2) Age (years)
Total sample (N = 16) 22.77 ± 2.31 29.9 ± 3.4
Male (N = 11) 23.07 ± 2.38 28.2 ± 2.4
Female (N = 5) 22.12 ± 2.25 29.3 ± 3.1
Table I. Anthropometric Measurements of the Subjects

The CPET data of the National Rowers pool of Sri Lanka are presented in Table II. In the context of CPET among Sri Lankan rowers, it was observed that male rowers exhibited significant differences in VO2 max, VO2 max AT, HR max, and VE compared to their female counterparts.

VO2 max CPET (mlKg−1min−1) VO2 max AT. (ml/kg/min) HRMax VE (ml/min)
Total 33.32 ± 6.69 27.12 ± 6.87 182.37 ± 7.28 133.63 ± 23.89
Male 33.01 ± 8.35 28.99 ± 5.91 181.82 ± 7.37 147.25 ± 12.76
Female 33.64 ± 6.27 23.16 ± 7.81 183.60 ± 7.76 103.68 ± 10.19
Table II. CPET Data of the National Rowers Pool of Sri Lanka

Table III depicts the total number of shuttles executed by the subjects alongside their VO2 max values derived from the beep test. In administering a beep test among Sri Lankan rowers, a noteworthy disparity was evident in the number of shuttle rowers performed, with males scoring significantly higher and their corresponding VO2 max values between male and female participants.

Total number of shuttles VO2 max.Beep (mlKg−1min−1)
Total 99 ± 15 49.26 ± 7.94
Male 87 ± 18 50.75 ± 8.78
Female 81 ± 17 45.99 ± 4.88
Table III. Total Number of Shuttles Performed by the Subjects and Their Respective VO2 Max Values of the Beep Test

The correlation between the total number of shuttles completed during the beep test and their corresponding VO2 max values with the VO2 max obtained during CPET are depicted in Tables IV and V, respectively. In the female rowers, a statistically significant and positive correlation was identified between the VO2 max values obtained from the gold standard CPET and those derived from the beep test.

R-value P-value
Total sample 0.27 0.33
Male 0.34 0.30
Female 0.88 0.50
Table IV. The Correlation between the Total Number of Shuttles and the CPET VO2 Max Values
R-value P-value
Total sample 0.3 0.39
Male 0.3 0.30
Female 0.9 0.05
Table V. The Correlation between the VO2 Max Values of the CPET and the Beep Test

Table VI presents the comparison between the mean VO2 max values of CPET and the beep test. The beep test consistently overestimated VO2 max compared to the gold standard CPET method in both male and female rowers.

Mean ± SD (ml/Kg/min−1) VO2 max gold standard CPET Mean ± SD (ml/Kg/min−1) VO2 max beep test Mean bias (ml/Kg/min−1) Under/overestimation P-value
Total sample 33.64 ± 6.69 49.26 ± 7.94 15.62 ± 1.25 0.001
Male 33.01 ± 8.35 50.75 ± 8.78 17.74 ± 0.43 0.006
Female 33.64 ± 6.27 45.99 ± 4.88 12.35 ± 1.39 0.043
Table VI. Comparison of the Mean VO2 Max Values of CPET and the Beep Test

Discussion

This study assessed the cardiopulmonary fitness of Sri Lankan Rowers using the gold standard CPET-VO2 max and Beep test as a field assessment. In a similar vein, Mageeet al. (2021) conducted an experimental study involving hockey players to assess the efficacy of the Beep test in predicting VO2 max compared to the gold standard CPET (Mageeet al., 2021). Their findings and the beep test equation by Legeret al. (1988) have overestimated VO2 max, consistent with the current study’s finding.

As Mageeet al. (2021) highlighted, fitness level is crucial when calculating VO2 max using different equations. In our study, the participants’ irregular training patterns due to the COVID-19 pandemic might have influenced the results due to reduced overall physical fitness.

Furthermore, a similar study was conducted by Chatterjeeet al. (2007) to validate the Beep test against the gold standard CPET. Their findings showed no significant relationship between age. They revealed a statistically significant difference, with the average VO2 max obtained from the treadmill test being higher than that acquired from the beep test, similar to the results of the current study. These consistencies suggest that the beep test may have limitations in accurately predicting VO2 max, and these limitations persist across different studies and populations.

The present study observed a significant discrepancy between the VO2 max values obtained from CPET and those from the Beep test. The Beep test significantly overestimated VO2 max, with overestimations more pronounced in female participants than male participants (33.7% vs. 26.8%). The study by Aandstadet al. (2011) involving military home guard soldiers and air force cadets suggests that while the beep test demonstrates reliability, the validity is less confident due to variability between measured and estimated VO2. Notably, running performance parameters, such as Shuttles Completed and Last Half Level (LHL) completed, contribute significantly to the equation, indicating the importance of these factors in beep test outcomes.

The study by Mageeet al. (2021) on female field hockey participants highlights variations in VO2 max predictions using different beep test equations. While some equations provide valid predictions, others, including the one used in the current study, overestimate VO2 max. The differences in anthropometrics, age, and fitness levels between populations may contribute to discrepancies in results. This underscores the need for caution when applying beep test equations across diverse populations.

The study by Purbaet al. (2021) introduces a new predictive modeling formula, the Ruli formula, suggesting its utility in predicting VO2 max from the beep test. The formula incorporates parameters like Total Shuttles, Body Weight, HR Max in the field test, and Field Temperature. Internal validity and reliability tests support the formula’s use, emphasizing the importance of considering multiple factors for accurate predictions.

In contrast, the study by Azizet al. (2005) on young, trained soccer players emphasized the significant correlations between beep test performance and measured VO2 max. However, differences in age, training schedules, and criteria for participant selection highlight potential influencing factors.

These findings emphasize the complexity of interpreting beep test results and the need to consider population-specific factors carefully when evaluating its validity and reliability. The current study’s limitations, such as a small sample size and testing during off-seasons, should be acknowledged when interpreting the overestimated VO2 max values obtained from the gold standard CPET.

Conclusion

In conclusion, our study underscores a notable overestimation of VO2 max by the beep test compared to the gold standard CPET, particularly evident in females. Despite this overestimation, gender-specific differences in CPET-measured VO2 max were insignificant, with male rowers exhibiting higher VO2 max AT. The beep test demonstrated a positive correlation with CPET results in female rowers. Still, no significant correlation was observed between total shuttle completion and CPET-measured VO2 max across the entire population and within gender subgroups. Male rowers demonstrated a significantly higher full shuttle completion during the beep test than females. These findings emphasize the caution needed when using beep test results as a substitute for CPET in assessing VO2 max, especially considering gender-specific variations and potential limitations in predicting aerobic capacity.

Limitations of the Study

This study, characterized by a broad age range spanning from 24–33 years, and the age variability among participants could introduce confounding factors affecting results. Furthermore, the small sample size (16 participants) with a discernible gender imbalance limits statistical sensitivity and generalizability. Additionally, since the study occurred during the COVID-19 pandemic and the off-season regular training sessions had been disrupted, players tended to engage in separate fitness sessions. This resultant heterogeneity in fitness levels poses a notable consideration.

References

  1. Aandstad, A., Holme, I., Berntsen, S., & Anderssen, S. A. (2011). Validity and reliability of the 20 meter shuttle run test in military personnel. Military Medicine, 176(5), 513–518.
     Google Scholar
  2. Aziz, A. R., Tan, F. H., & Teh, K. C. (2005). A pilot study comparing two field tests with the treadmill run test in soccer players. Journal of Sports Science & Medicine, 4(2), 105.
     Google Scholar
  3. Chatterjee, P., Banerjee, A. K., Debnath, P., Bas, P., & Chatterjee, B. (2007). Validity of 20-metre multi stage shuttle run test for estimation of maximum oxygen uptake in Indian male university students promotion, fitness and wellness. African Journal for Physical Health Education, Recreation and Dance, 12(4), 461–467.
     Google Scholar
  4. Cheng, J. C., Chiu, C. Y., & Su, T. J. (2019). Training and evaluation of human cardiorespiratory endurance based on a fuzzy algorithm. International Journal of Environmental Research and Public Health, 16(13), 1–20.
     Google Scholar
  5. Dalui, R., & Bandyopadhyay, A. (2017). Pulmonary function of young Indian male judo and karate players. Biology of Exercise, 13(1), 33–43.
     Google Scholar
  6. DeBlauw, J. A., Stein, J. A., Blackman, C., Haas, M., Makle, S., Echevarria, I., et al. (2023). Heart rate variability of elite female rowers in preparation for and during the national selection regattas: A pilot study on the relation to on water performance. Frontiers in Sports and Active Living, 5, 1–10.
     Google Scholar
  7. Joyner, M. J., & Coyle, E. F. (2008). Endurance exercise performance: The physiology of champions. The Journal of Physiology, 586(1), 35–44.
     Google Scholar
  8. Leger, L. A., Mercier, D., Gadoury, C., & Lambert, J. (1988). The multistage 20 metre shuttle run test for aerobic fitness. Journal of Sports Sciences, 6(2), 93–101.
     Google Scholar
  9. Linder, S. P., Wendelken, S., & Clayman, J. (2006, August). Detecting exercise induced stress using the photoplethysmogram. 2006 International Conference of the IEEE Engineering in Medicine and Biology Society, IEEE, 5109–5112.
     Google Scholar
  10. Magee, M. K., White, J. B., Merrigan, J. J., & Jones, M. T. (2021). Does the multistage 20-m shuttle run test accurately predict VO2max in NCAA division I women collegiate field hockey athletes? Sports, 9(6), 1–11.
     Google Scholar
  11. Purba, R. H., Tulaar, A. B., Yunus, F., Ibrahim, E. I., Abdullah, M., Tamin, T. Z., et al. (2021). Model prediction maximum oxygen intake (VO2max) using the bleep test in male junior athletes. Systematic Reviews in Pharmacy, 12(1), 1243–1247.
     Google Scholar
  12. Raghuveer, G., Hartz, J., Lubans, D. R., Takken, T., Wiltz, J. L., Mietus-Snyder, M., et al. (2020). Cardiorespiratory fitness in youth: An important marker of health: A scientific statement from the American heart association. Circulation, 142(7), e101–e118.
     Google Scholar