EMG Threshold Determination in Eight Lower Limb Muscles During Cycling Exercise: A Pilot Study

Abstract

The first aim of this study was to verify the occurrence of the EMG threshold (EMG_Th) in each of eight lower limb muscles (vastus lateralis [VL], vatus medialis [VM], rectus femoris [RF], semimembranosus [SM], biceps femoris [BF], gastrocnemius lateralis [GL] and medialis [GM], and tibialis anterior [TA]) during incremental cycling exercise. The second aim was to investigate the test-retest reproducibility of the EMG_Th occurrence. Six sedentary male subjects (27 ± 1 years) performed the same incremental cycling test until exhausted, (workload increments of 25 W/min starting at 100 W) twice. During the tests, the EMG Root Mean Square (RMS) response was studied in the aforementioned muscles. The EMG_Th was detected mathematically from the RMS vs. workload relationship. All the subjects showed an EMG_Th in the VL muscle, and the response was reliable in both tests (246 ± 33 W and 254 ± 33 W for the first and second test, respectively; coefficient of variation: 9.6 %, standard error of measurement: 28.9). However, few of them showed an EMG_Th in the other muscles, especially in RF, SM or GM. When present, the EMG_Th occurred at 75 - 80 % of the peak power output obtained during the tests. Our results suggest that EMG_Th determination can be used as a reliable method for studying neuromuscular adjustments in the VL of untrained individuals, but not in other lower limb muscles.

Key words

Root mean square - cycle-ergometer - neuromuscular fatigue - motor unit

References

• 1 Airaksinen O, Remes A, Kolari P J, Sihvonen T, Hanninen O, Penttila I. Real-time evaluation of anaerobic threshold with rms-EMG of working and nonworking muscles during incremental bicycle ergometer test.  Acupunct Electrother Res. 1992;  17 259-271
• 2 Bigland-Ritchie B, Johansson R, Lippold O C, Smith S, Woods J J. Changes in motoneurone firing rates during sustained maximal voluntary contractions.  J Physiol. 1983;  340 335-346
• 3 Bigland-Ritchie B, Woods J J. Integrated EMG and oxygen uptake during dynamic contractions of human muscles.  J Appl Physiol. 1974;  36 475-479
• 4 Bland J, Altman D. Statistical methods for assessing agreement between two methods of clinical measurement.  Lancet. 1986;  8 307-310
• 5 Chwalbinska-Moneta J, Kaciuba-Uscilko H, Krysztofiak H, Ziemba A, Krzeminski K, Kruk B, Nazar K. Relationship between EMG blood lactate, and plasma catecholamine thresholds during graded exercise in men.  J Physiol Pharmacol. 1998;  49 433-441
• 6 Darques J L, Decherchi P, Jammes Y. Mechanisms of fatigue-induced activation of group IV muscle afferents: the roles played by lactic acid and inflammatory mediators.  Neurosci Lett. 1998;  257 109-112
• 7 Darques J L, Jammes Y. Fatigue-induced changes in group IV muscle afferent activity: differences between high- and low-frequency electrically induced fatigues.  Brain Res. 1997;  750 147-154
• 8 Ericson M. On the biomechanics of cycling. A study of joint and muscle load during exercise on the bicycle ergometer.  Scan J Rehabil Med. 1986;  16 165-172
• 9 Essen B. Intramuscular substrate utilization during prolonged exercise.  Ann NY Acad Sci. 1977;  301 30-44
• 10 Gamet D, Duchene J, Garapon-Bar C, Goubel F. Surface electromyogram power spectrum in human quadriceps muscle during incremental exercise.  J Appl Physiol. 1993;  74 2704-2710
• 11 Hanon C, Thepaut-Mathieu C, Hausswirth C, Le Chevallier J. Electromyogram as an indicator of neuromuscular fatigue during incremental exercise.  Eur J Appl Physiol. 1998;  78 315-323
• 12 Hermens H, Freriks B, Disselhorst-Klug C, Rau G. Development of recommendations for sEMG sensors and sensor placement procedures.  J Electromyogr Kinesiol. 2000;  10 361-374
• 13 Hug F, Bendahan D, Le Fur Y, Cozzone P J, Grélot L. Heterogeneity of muscle recruitment pattern during pedalling in professional road cyclists: a magnetic resonance imaging and electromyography study.  Eur J Appl Physiol. 2004;  92 334-342
• 14 Hug F, Faucher M, Kipson N, Jammes Y. EMG signs of neuromuscular fatigue related to the ventilatory threshold during cycling exercise.  Clin Physiol Funct Imaging. 2003;  23 208-214
• 15 Hug F, Faucher M, Marqueste T, Guillot C, Kipson N, Jammes Y. Electromyographic signs of neuromuscular fatigue are concomitant with further increase in ventilation during static handgrip.  Clin Physiol Funct Imaging. 2004;  24 25-32
• 16 Hug F, Laplaud D, Savin B, Grélot L. Occurrence of electromyographic and ventilatory thresholds in professional road cyclists.  Eur J Appl Physiol. 2003;  90 643-646
• 17 Kadefors R, Kaiser E, Petersen I. Dynamic spectrum analysis of myo-potentials and with special reference to muscle fatigue.  Electromyography. 1968;  8 39-74
• 18 Kranz H, William A, Cassel J, Caddy S, Silberstein R. Factors determining the frequency content of the electromyogram.  J Appl Physiol. 1983;  55 392-399
• 19 Lepers R, Hausswirth C, Maffiuletti N, Brisswalter J, van Hoecke J. Evidence of neuromuscular fatigue after prolonged cycling exercise.  Med Sci Sports Exerc. 2000;  32 1880-1886
• 20 Lepers R, Maffiuletti N, Rochette L, Brugniaux J, Millet G. Neuromuscular fatigue during a long-duration cycling exercise.  J Appl Physiol. 2002;  92 1487-1493
• 21 Lepers R, Millet G Y, Maffiuletti N A. Effect of cycling cadence on contractile and neural properties of knee extensors.  Med Sci Sports Exerc. 2001;  33 1882-1888
• 22 Lindstrom L, Magnusson R, Petersen I. Muscular fatigue and action potential conduction velocity changes studied with frequency analysis of EMG signals.  Electromyography. 1970;  10 341-356
• 23 Lucia A, Sanchez O, Carvajal A, Chicharro J L. Analysis of the aerobic-anaerobic transition in elite cyclists during incremental exercise with the use of electromyography.  Br J Sports Med. 1999;  33 178-85
• 24 Lucia A, Vaquero A F, Perez M, Sanchez O, Sanchez V, Gomez M A, Chicharro J L. Electromyographic response to exercise in cardiac transplant patients: a new method for anaerobic threshold determination?.  Chest. 1997;  111 1571-1576
• 25 Moritani T, Tanaka H, Yoshida T, Ishii C, Shindo M. Relationship between myoelectric signals and blood lactate during incremental forearm exercise.  Am J Phys Med. 1984;  63 122-132
• 26 Nagata A, Muro M, Moritani T, Yoshida T. Anaerobic threshold determination by blood lactate and myoelectric signals.  Jpn J Physiol. 1981;  31 585-597
• 27 Nilsson J, Tesch P, Thorstensson A. Fatigue and EMG of repeated fast voluntary contractions in man.  Acta Physiol Scand. 1977;  101 194-198
• 28 Santos E L, Giannella-Neto A. Comparison of computerized methods for detecting the ventilatory thresholds.  Eur J Appl Physiol. 2004;  93 315-324
• 29 Taylor A D, Bronks R. Electromyographic correlates of the transition from aerobic to anaerobic metabolism in treadmill running.  Eur J Appl Physiol. 1994;  69 508-515
• 30 Taylor A D, Bronks R. Reproducibility and validity of the quadriceps muscle integrated electromyogram threshold during incremental cycle ergometry.  Eur J Appl Physiol. 1995;  70 252-257
• 31 Viitasalo J T, Luhtanen P, Rahkila P, Rusko H. Electromyographic activity related to aerobic and anaerobic threshold in ergometer bicycling.  Acta Physiol Scand. 1985;  124 287-293
• 32 Wolosker H, de Meis L. pH-dependent inhibitory effects of Ca2 +, Mg2 +, and K+ on Ca2 + efflux mediated by sarcoplasmic reticulum ATPase.  Am J Physiol. 1994;  266 1376-1381