Acute cardiopulmonary responses of women in strength training

Abstracts

OBJETIVE: Investigate the cardiopulmonary responses of one strength training session in young women. METHOD: Twenty-three women aged between 18 and 29 years participated in this study. All the volunteers were submitted to the following tests: cardiopulmonary and one-repetition maximum (1-RM). The strength training protocol had emphasis on muscular hypertrophy, three sets from eight to twelve repetitions under 70% of 1-RM, with a one minute thirty-second break between sets. During the training session, the cardiopulmonary variables were measured with a metabolic gas analyzer and a telemetry module. RESULTS: The results of the oxygen consumption in the training session were from 8.43 + 1.76 ml/kg/min and of the heart rate of 108.08 + 15.26 bpm. The results of the oxygen consumption and of the heart rate in the training were lower (p < 0.01) than in the ventilatory threshold and of the oxygen consumption and the heart rate reserves. CONCLUSION: The obtained data show that the present protocol of strength training provided low overload to the cardiopulmonary system of young women.

oxygen consumption; heart rate; pulmonary ventilation

OBJETIVO: Investigar as respostas cardiopulmonares de uma sessão de treinamento de força em mulheres jovens. MÉTODO: Participaram do estudo 23 mulheres, com idade entre 18 e 29 anos. Todas as voluntárias foram submetidas aos seguintes testes: cardiopulmonar e de uma repetição máxima (1-RM). O protocolo de treinamento de força teve ênfase em hipertrofia muscular, três séries de oito a 12 repetições a 70% de 1-RM, com intervalos de um minuto e 30 segundos entre as séries. Durante a sessão de treinamento foi realizada a medida das variáveis cardiopulmonares por meio de analisador de gases metabólicos e módulo de telemetria. RESULTADOS: Os resultados do consumo de oxigênio da sessão de treinamento foram de 8,43 ± 1,76 ml/kg/min e da frequência cardíaca de 108,08 ± 15,26 bpm. Os resultados do consumo de oxigênio e da frequência cardíaca do treino foram inferiores (p < 0,01) ao do limiar ventilatório e das reservas do consumo de oxigênio e da frequência cardíaca. CONCLUSÃO: Os dados obtidos indicam que o presente protocolo de treinamento de força proporcionou pequena sobrecarga ao sistema cardiorrespiratório de mulheres jovens.

consumo de oxigênio; frequência cardíaca; ventilação pulmonar

,ORIGINAL ARTICLE

EXERCISE AND SPORTS MEDICINE CLINIC

Acute cardiopulmonary responses of women in strength training

Márcio Antônio Gonsalves Sindorf^I; Gabriel Soliani Celante^I; Maria Imaculada de Lima Montebelo^II; João Paulo Borin^III; Pamela Roberta Gomes Gonelli^I; Ricardo Adamoli Simões^I; Thiago Mattos Frota de Souza^I; Marcelo de Castro Cesar^I

^IPhysical Education Course - Health Sciences School - Methodist University of Piracicaba (UNIMEP) - São Paulo - Brazil

^IIExact and Nature Sciences School - Methodist University of Piracicaba (UNIMEP) - São Paulo - Brazil

^IIIState University of Campinas (Unicamp) - São Paulo - Brazil

Mailing address

ABSTRACT

OBJETIVE: To investigate the cardiopulmonary responses of one strength training session in young women.

METHOD: Twenty-three women aged between 18 and 29 years participated in this study. All the volunteers were submitted to the following tests: cardiopulmonary and one-repetition maximum (1-RM). The strength training protocol had emphasis on muscular hypertrophy, three sets from eight to twelve repetitions under 70% of 1-RM, with a one minute thirty-second break between sets. During the training session, the cardiopulmonary variables were measured with a metabolic gas analyzer and a telemetry module.

RESULTS: The results of the oxygen consumption in the training session were from 8.43 ± 1.76 ml/kg/min and of the heart rate of 108.08 ± 15.26 bpm. The results of the oxygen consumption and of the heart rate in the training were lower (p < 0.01) than in the ventilatory threshold and in the oxygen consumption and the heart rate reserves.

CONCLUSION: The obtained data show that the present protocol of strength training provided low overload to the cardiopulmonary system of young women.

Keywords: oxygen consumption, heart rate, pulmonary ventilation.

INTRODUCTION

Strength training has been subject of several studies, both for its direct relation with performance of many sports modalities and the proved benefits in the prevention and rehabilitation of musculoskeletal injuries and chronic diseases, as well as in training programs having health and quality of life as goal¹. Moreover, we stress the positive effects of strength training in body composition and muscle strength development^2,3.

Concerning strength training with the purpose of muscular hypertrophy in young adults, the American College of Sports Medicine (ACSM)^1,4 recommends from eight to ten exercises, with one or more sets of eight to 12 repetitions at 70-85% of 1-RM with one to two-minute intervals between exercises. The cardiorespiratory and/or metabolic adjustments in strength training have been investigated in previous studies ^5-8; however, they have not been so in protocols such as the one for young women.

The cardiopulmonary test allows determining the maximum oxygen consumption (VO_2max) and the anaerobic threshold by ventilatory method (VT), these are important indices of cardiorespiratory functional limitation⁹. Percentage values of VO_2max (50-85%)¹⁰ and of the maximum heart rate (55/65%-90%)¹ are used in the prescription of aerobic training intensities. The American College of Sports Medicine¹ proposes aerobic training intensities of 40-50% of the oxygen consumption reserve (VO₂) and heart rate (HR).

The present study had as aims to determine the cardiopulmonary responses of a strength training session in Young women, and to compare the oxygen consumption and heart rate values of the strength training session with values of ventilatory threshold and reserve to verify the cardiorespiratory overload in strength training proposed for young and healthy individuals^1,4.

METHODS

Approach

23 women aged between 18 and 29 years, healthy, non-smokers, under strength training for at least six months were studied. After having received explanation on the project, the volunteers signed the Free and Clarified Consent Form. The study was approved by the Ethics in Research Committee of the Methodist University of Piracicaba, protocol # 06/08.

The volunteers answered a questionnaire on the health history before the experimental protocol in an attempt to discard counter indications to the tests and training.

EXPERIMENTAL PROTOCOL

Tests protocol

After the clinical evaluation, the volunteers were submitted to a cardiopulmonary and muscular tests protocol with intervals of 48 to 72 hours. All tests were conducted in the Laboratory of Anthropometric Evaluation and Physical Exertion and in the Center of Quality of Life of the Physical Education Course of the Health Sciences School (FACIS) of the Methodist University of Piracicaba (UNIMEP).

Cardiopulmonary test

The volunteers were submitted to the cardiopulmonary test on treadmill (Inbrasport ATL^®), with continuous incremental protocol with initial load of 4.0 km/h (three minutes), and increment of 1.0 km/h at every minute until 10.0 km/h; afterwards, increments of 2.5% of inclination/minute, until exhaustion¹¹.

The tests were continuously monitored in the MC5, AVF and V2 derivations, with electrocardiographic records at the end of each stage and in recovery.

Measurement of oxygen consumption, carbonic gas production and pulmonary ventilation was directly performed with a metabolic gas analyzer (VO2000 - Medical Graphics^®). The maximum oxygen consumption and anaerobic threshold were determined by ventilatory method⁹.

Heart rate during the treadmill test was measured at every 60 seconds through telemetry (Polar^® Vantage NV) when the maximum heart rate (HR_max) and ventilator threshold (HRVT) were determined.

Tests of one repetition maximum

The 1-RM test was performed according to the following exercise order: bench press, leg-press 45º, back pull, quadriceps extension, back military press with barbell, back hamstrings flexion, high pulley overhead, triceps extension with barbell and barbell curl¹².

Measurement of the cardiopulmonary responses during strength training

After the initial tests, the volunteers performed one strength training session with monitoring of cardiopulmonary variables with a metabolic gas analyzer and telemetry (VO2000 - Medical Graphics^®).

The pre-test measurements of the volunteers were determined after their recovery time at dorsal decubitus for 30 minutes. The cardiopulmonary measurements were taken during 12 minutes at rest, where the two first minutes of measurement were discarded, the oxygen consumption at rest determined (VO₂ rest) and heart rate at rest (HR rest) determined by the mean of the last ten minutes.

The reserve oxygen consumption (VO₂ reserve) and the reserve hear rate (HR reserve) were calculated by the equations¹³.

Subsequently to the measurements at rest, the volunteers performed static stretching and then started training in the same eight exercises of the 1-RM tests. The strength training session had emphasis on muscular hypertrophy^1,4: three sets of eight to 12 repetitions at 70% of 1-RM, with one-minute intervals and 30 seconds between sets and exercises. Specific warm-up with about 10 to 15% of 1-RM on the bench press, leg press 45º and back pull was performed prior to the beginning of the session.

During the strength training session, oxygen consumption (l/min and in ml/kg/min), carbon dioxide production (l/min), gas exchanges ratio, pulmonary ventilation (l/min), ventilatory equivalents for oxygen and carbon dioxide, oxygen pulse (ml/beat) and heart rate (bpm) through a metabolic gas analyzer and telemetry module were measured. After the end of the training session, the volunteers rested at dorsal decubitus, until the VO₂ values were similar to the pre-test ones.

RESULT ANALYSIS

Descriptive analysis of the results was performed for all variables. The results of the cardiopulmonary variables were expressed in absolute values, and the VO₂ and HR values as well in maximum percentage values, obtained in the cardiopulmonary test.

The values of oxygen consumption and heart rate during the strength training were compared with the ventilatory threshold and reserve of VO₂ and of HR values. The Shapiro-Wilk test was used for data normality and the Student's t test for comparison of results. Significance level adopted was of 5%.

RESULTS

Table 1 evidences the result of the cardiopulmonary test; table 2 presents the result of the 1-RM test and the load used in the training session, and table 3, the data of the cardiopulmonary variables in the strength training session. The duration of the strength training session was in average of 54 minutes and 43 seconds. In the training session, the VO₂ values were 18.41 ± 0.03% of VO_2max, and the HR values were 56.10 ± 0.06% of HR_max.

The comparison of the VO₂ result during training presented values lower than the VO₂VT to the minimum of reserve VO₂ recommended for aerobic training¹ (figures 1 and 2). The HR was also lower in the training than in the HRVT and in the minimum reserve HR recommended for aerobic training¹ (figures 3 and 4). The VO₂ values returned to the pre-test values before 30 minutes of recovery.

DISCUSSION

Few studies which investigate the acute cardiopulmonary responses to a strength training protocol in women have been reported in the literature; however, in the last years, strength training has been widely studied and recommended as prevention for chronic diseases^3,14, and the participation of women in strength training also remarkably increased ^15,16. Thus, it is important to acknowledge the cardiopulmonary responses of women in strength training.

The results obtained indicate that the VO₂ of strength training was low compared to the VO_2max, suggesting hence that this training provided small overload to the cardiorespiratory system. The VO₂ values in the training session were lower than in the VT and the minimum recommendation of reserve VO₂ for aerobic training¹.

These results are in agreement with previous studies which investigated the adaptations to the cardiorespiratory system in women submitted to strength training, and found little or no improvement in cardiorespiratory fitness^2,17-20.

The majority of the studies found in the literature which investigated the cardiopulmonary responses in strength training ^5,7,8 aimed at men or protocols different from the one used in the present study ^6,21,22.

Bizen et al.²³ investigated the metabolic responses of a strength training in female individuals. The training consisted of three sets of tem repetitions, 60 seconds of interval between exercises, nine exercises at 70% 1-RM. The authors found VO₂ mean value of 0.68 L/min, which is higher than in the present study. Such fact seems to be justified due to the shorter interval between exercises, and no comparisons were made with the VT and the VO₂ minimum and reserve HR proposed for aerobic training¹.

The HR and VO₂ obtained in the present study were lower than in physical exercises modalities such as walking²⁴, aerobic gymnastics and treadmill running²⁵, cycling on a cycle ergometer at submaximal load^26,27, pump, step, body combat and spinning²⁸, as well as in jump fit classes²⁹.

The HR obtained in the present study was below the VT and reserve HR¹, despite the fact that in the maximum percentage values, it had been lower than the recommendation for aerobic training. However, the HR is not considered the most reliable parameter for controlling intensity of strength training, since there is no linear correlation between the HR and VO₂ in strength training^5,6.

In the present study, low O₂ pulse values have been found, these values were much lower than the ones found in aerobic gymnastics and treadmill running²⁵, walking²⁴, cycling on a cycle ergometer at submaximal load^26,28. The low O₂ pulse of this study indicate that weight training led to excessive chronotropic response concerning the energetic demand, corroborating further studies which indicate that HR is not a suitable parameter to control intensity of strength training^5,6.

The pulmonary ventilation values in absolute values were lower than in women cycling on cycle ergometer²⁶, indicating that the ventilatory load was small; however, the values of ventilatory equivalents for oxygen^26,28 and carbon dioxide ²⁸ were higher than the ones for women cycling on cycle ergometer at submaximal load, indicating hence that weight training led to exaggerated ventilator response concerning the metabolic demand³⁰.

The acute responses to strength training found in the present study corroborate the results by Dionne et al.¹⁷, who investigated the adaptations to a strength training program with a protocol with three sets of ten repetitions in nine exercises with interval between sets of 60-90 seconds, for six months, and did not find alteration in the VO_2max in young women.

The results of this study indicate that the strength training proposed by the American College of Sports Medicine^1,4 for muscular hypertrophy and health maintenance did not promote sufficient stimulus for improvement in cardiorespiratory fitness of the young women studied here and aerobic training was necessary.

CONCLUSION

The results obtained show that the strength training protocol studied provided little aerobic overload for improvement of the cardiorespiratory system of trained young women. It can be concluded that the strength protocol proposed by the ACSM per se does not define alterations in the cardiorespiratory fitness.

ACKNOWLEDGEMENTS

The authors thank the Research Support Foundation of São Paulo State - FAPESP, for its grant, the Coordination for the Improvement of Higher Level Personnel - CAPES, for the Master's scholarships and the National Council for Scientific and Technological Development - CNPq, for the scientific initiation scholarships.

All authors have declared there is not any potential conflict of interests concerning this article.

REFERENCES

• 1. American College of Sports Medicine. The recommended quantity and quality of exercise for developing and maintaining cardiorespiratory and muscular fitness and flexibility in health adults. Med Sci Sports Exerc 1998;30:975-91.
• 2. Souza TMF, Cesar MC, Borin JP, Gonelli PRG, Simões RA, Montebelo MIL. Efeitos do treinamento de resistência de força com alto número de repetições no consumo máximo de oxigênio e limiar ventilatório de mulheres. Rev Bras Med Esporte 2008;14:513-7.
• 3. Kraemer WJ, Ratamess NA. Fundamentals of resistance training: Progression and exercise prescription. Med Sci Sports Exerc 2004;6:674-88.
• 4. American College of Sports Medicine. Progression models in resistance training for healthy adults. Med Sci Sports Exerc 2009;41:687-708.
• 5. Hurley BF, Seals DR, Ehsani AA, Cartier LJ, Dalsy GP, Hagberg JM, et al. Effects of high-intensity strenght training on cardiovascular function. Med Sci Sports Exerc 1984;16:483-88.
• 6. Wilmore JH, Parr RB, Ward P, Vodak PA, Barstow TJ, Pipes TV, et al. Energy cost of circuit weight training. Med Sci Sports Exerc 1978;10:75-8.
• 7. Glowacki SP, Martin SE, Maurer A., Baek W, Green JS, Crouse SF. Effects of resistance, endurance, and concurrent exercise outcomes in men. Med Sci Sports Exerc 2004;36:2119-27.
• 8. Hunter GR, Seelhorst D, Snynder S. Comparison of metabolic and heart rate responses to super slow vs. traditional resistance training. J Strength Cond Res 2003;17:76-81.
• 9. Wasserman K, Hansen JE, Sue DY, Casaburi R, Whipp BJ. Principles of Exercise Testing and Interpretation. 3. ed., Baltimore: Lippincott Williams & Wilkins, 1999, 556p.
• ¹⁰
  American College of Sports Medicine. The recommended quantity and quality of exercise for developing and maintaining cardiorespiratory and muscular fitness in health adults. Med Sci Sports Exerc 1990;22:265-74.
• 11. Cesar MC, Pardini DP, Barros TL. Efeitos do exercício de longa duração no ciclo menstrual, densidade óssea e potência aeróbia de corredoras. R bras Ci e Mov 2001;9:7-13.
• 12. Brown LE, Weir JP. ASEP - Procedures recommendation I: accurate assessment of muscular strength and power. J Exerc Physiol 2001;4:1-21.
• 13. Karvonen M, Kentala K, Musta O. The effects of training heart rate: a longitudinal study. Ann Med Exptl Biol Fenn 1957;35:307-15.
• 14. Williams M.A. Resistance exercise in individuals with and without cardiovascular disease: 2007 Update. Circulation 2007;116:572-84.
• 15. Kraemer WJ, Nindl BC, Ratamess NA, Gotshalk LA, Volek JS, Fleck SJ, et al. Changes in muscle hypertrophy in women with periodized resistance training. Med Sci Sports Exerc 2004;36:697-708.
• 16. Schmitz KH, Hannan PJ, Stovitz SD, Bryan CJ, Warren M, Jensen MD. Strength training and adiposity in premenopausal women: strong, healthy, and empowered study. Am J Clin Nutr 2007;86:566-72.
• 17. Dionne IJ, Melançon MO, Brochu M, Ades PA, Poelhman ET. Age - related differences in metabolic adaptations following resistance training in women. Experimental Gerontology 2004;39:133-8.
• 18. Hoff J, Helgerud J, Wisloff U. _Maximal strength training improves work economy in trained female cross-country skiers. Med Sci Sports Exerc 1999;31:870-77.
• 19. Bishop D, Jenkins DG, Mackinnon LT, Mcenniery m, Carey MF. The effects of strength training on endurance performance and muscle characteristics. Med Sci Sports Exerc 1999;31:886-91.
• 20. Cesar MC, Borin JP, Gonelli PRG, Simões RA, Souza TMF, Montebelo MIL. The effect of local muscle endurance training on cardiorespiratory capacity in young women. J Strength Cond Res 2009;23:1637-43.
• 21. Phillips WT, Ziuraitis JR. Energy cost of the ACSM single-set resistance training protocol. J Strength Cond Res 2003;17:350-5.
• 22. Phillips WT, Ziuraitis JR. Energy cost of single-set resistence training in older adults. J Strength Cond Res 2004;18:606-9.
• 23. Bizen CA, Swan PD, Manore MM. Postexercise oxygen consumption and substrate use after resistance exercise in women. Med Sci Sports Exerc 2001;33:932-8.
• 24. Elsangedy HM, Krinski K, Buzzachera CF, Nunes RFH, Almeida FAM, Baldar C, et al. Respostas fisiológicas e percentuais obtidas durante a caminhada em ritimo autosselecionado por mulheres com diferentes índices de massa corporal. Rev Bras Med Esporte 2009;15:287-90.
• 25. Parker SB, Hurley BF, Hanlon DP, Vaccaro P. Failure of target heart rate to accurately monitor intensity during aerobic dance. Med Sci Sports Exerc 1989;21:230-4.
• 26. Atomi Y, Ito K, Iwasaki H, Miyashita M. Effects of intensity and frequency of training on aerobic work capacity of young females. J Sports Med 1978;18:3-9.
• 27. Redman LM, Scroop GC, Westlander G, Norman R. Effect of a synthetic progestin on the exercise status of sedentary young women. J Clin Endocrinol Metab 2005;90:3830-7.
• 28. Rixon KP, Rehor PR, Bemben MG. Analysis of the assessment of caloric expenditure in four modes of aerobic dance. J Strength Cond Res 2006;20:593-6.
• 29. Furtado E, Simão R, Lemos A. Análise do consume de oxigênio, frequência cardiac e dispêndio ernegético, durante as aulas do Jump Fit. Rev Bras Med Esporte 2004;10:371-5.
• 30. Wasserman K, Whipp BJ. Exercise physiology in health and disease. Am Rev Resp Dis 1975;112:219-49.

Publication Dates

• Publication in this collection
  16 Apr 2013
• Date of issue
  Feb 2013