Brazilian Electromyography Journal of and Medical heart and rate Biological responses Research to isometric (1999) exercise 32: 115-120 ISSN 0100-879X Short Communication 115 Evaluation of electromyographic activity and heart rate responses to isometric exercise. The role played by muscular mass and type E. Silva 1,4, L. Oliveira 1, A.M. Catai 1, P. Ferreira-Filho 2, F. Bérzin 3 and L. Gallo Jr. 5 1 Laboratório de Fisioterapia Cardiovascular, Departamento de Fisioterapia, and 2 Departamento de Estatística, Universidade Federal de São Carlos, São Carlos, SP, Brasil 3 Departamento de Morfologia, Faculdade de Odontologia de Piracicaba, Universidade Estadual de Campinas, Piracicaba, SP, Brasil 4 Departamento de Fisiologia e Biofísica, Universidade Estadual de Campinas, Campinas, SP, Brasil 5 Divisão de Cardiologia, Hospital das Clínicas, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brasil Correspondence E. Silva Laboratório de Fisioterapia Cardiovascular Departamento de Fisioterapia, UFSCar Via Washington Luiz, km 235 13565-905 São Carlos, SP Brasil Fax: +55-16-271-2081 E-mail: esters@power.ufscar.br Research supported by CNPq (No. 520.686/95-0). Publication supported by FAPESP. Received July 20, 1998 Accepted October 28, 1998 Abstract Key words Knee Isometric exercise Heart rate Electromyography Rectus femoris Biceps femoris
116 E. Silva et al.
Electromyography and heart rate responses to isometric exercise 117 D D
118 E. Silva et al. Figure 1 - Heart rate (DHR - beats/min) responses at 10 s of maximal isometric exercise tests. (A) and (C) report the values for the unilateral right and left extension and flexion exercises, and (B) and (D) report the values for the bilateral knee extension and flexion exercise. Data are reported as medians, 1st, and 3rd quartiles and range. DHeart rate (beats/min) 60 50 40 30 20 Max Min 10 0 A B C D Knee extension Knee flexion 1st and 3rd quartiles Median Outliers Extremes
Electromyography and heart rate responses to isometric exercise 119 EMG amplitude (µv) RMS 2800 2400 2000 1600 1200 800 Max Min Figure 2 - Amplitude of electromyographic signals are reported as root mean square values (RMS) (µv) at 10 s of maximal isometric exercise tests, with knee extension and flexion. (A) and (C) report the values for the unilateral right and left extension and flexion exercises and (B) and (D) report the RMS values, as a sum of both knees, from bilateral extension and flexion exercises. Data are reported as medians, 1st and 3rd quartiles and range. 400 1st and 3rd quartiles 0 A B C D Knee extension Knee flexion Median Outliers References Acknowledgments 1. Martin CE, Shaver JA, Leon DF, Thompson ME, Reddy PS & Leonard JJ (1974). Autonomic mechanisms in hemodynamic responses to isometric exercise. Journal of Clinical Investigation, 54: 104-115. 2. Maciel BC, Gallo Jr L, Marin-Neto JA & Martins LEB (1987). Autonomic nervous control of the heart rate during isometric exercise in normal man. Pflügers Archives, European Journal of Physiology, 408: 173-177. 3. Ramos UM, Mundale MO, Awad EA, Witsoe DA, Cole TM, Olson M & Kottke FJ (1973). Cardiovascular effects of spread of excitation during prolonged isometric exercise. Archives of Physical Medicine and Rehabilitation, 54: 496-504. 4. Mitchell JH, Pyne HR, Saltin B & Schibye B (1980). The role of muscle mass in the cardiovascular response to static contractions. Journal of Physiology, 309: 45-54. 5. Seals DR, Washburn RA, Hanson PG, Painter PL & Nagle FJ (1983). Increased cardiovascular response to static contraction of larger muscle groups. Journal of Applied Physiology: Respiratory Environmental and Exercise Physiology, 54: 434-437. 6. McCloskey DI & Streatfeild KA (1975). Muscular reflex stimuli to the cardiovas-
120 E. Silva et al. cular system during isometric contractions of muscle groups of different mass. Journal of Physiology, 250: 431-441. 7. Williams CA (1991). Effect of muscle mass on the pressor response in man during isometric contractions. Journal of Physiology, 435: 573-584. 8. NG AV, Agre JC, Hanson P, Harrington MS & Nagle FJ (1994). Influence of muscle length and force on endurance and pressor responses to isometric exercise. Journal of Applied Physiology, 76: 2561-2569. 9. Basmajian JV & De Luca CJ (1985). Muscle Alive, Their Functions Revealed by Electromyography. 5th edn. Williams & Wilkins, Baltimore. 10. Monteiro-Pedro V (1995). Atividade eletromiográfica do músculo vasto medial oblíquo em esforços isométricos e isotônicos das articulações do quadril e do joelho. Doctoral thesis, Faculdade de Odontologia de Piracicaba, UNICAMP, Piracicaba. 11. Silva E, Catai AM, Trevelin LC, Guimarães JO, Silva Jr LP, Silva LMP, Oliveira L, Milan LA, Martins LEB & Gallo Jr L (1994). Design of computerized system to evaluate the cardiac function during dynamic exercise. Physics in Medicine and Biology, 33: 409 (Abstract). 12. Siegel S (1956). Nonparametric Statistics for the Behavioral Sciences. McGraw-Hill, Tokyo. 13. Erim Z, De Luca CJ, Mineo K & Aoki T (1996). Rank-ordered regulation of motor units. Muscle and Nerve, 19: 563-573. 14. Polgar J, Johnson MA, Weigtman D & Appleton D (1973). Data on fibre size in thirty-six human muscles - an autopsy study. Journal of Neurological Sciences, 19: 307-318. 15. Johnson MA, Weightman D & Applenton D (1973). Data on the distribution of fibre types in thirty-six human muscles. Journal of Neurological Sciences, 18: 111-129.