Plantar Flexion Torque as a Function of Time of Day

Abstract

The possible peripheral and/or central origin in the mechanisms responsible for day-time fluctuation in maximal torque of the triceps surae muscle were investigated with a special emphasis on antagonist muscle coactivation. Eleven healthy male subjects (physical education students) took part in this investigation. The electromechanical properties of the plantar flexor muscles were recorded at two different times of day: between 06 : 00 h and 08 : 00 h in the morning and between 17 : 00 h and 19 : 00 h in the evening. To investigate peripheral mechanisms, the posterior tibial nerve was stimulated at rest, using percutaneous electrical stimuli, to evoke single twitch, double twitch, and maximal tetanic contraction (100 Hz). Maximal voluntary contraction of the plantar flexors was also assessed by means of the relative electromyographic activity of respective agonist and antagonist muscles (soleus, gastrocnemius medialis, gastrocnemius lateralis, and tibialis anterior). A double twitch was delivered during maximal voluntary plantar flexion to record muscle activation (i.e., interpolated twitch technique). The coactivation level of the tibialis anterior muscle during plantar flexion was calculated. The results indicated a significant decrease in maximal voluntary muscle torque of triceps surae in the evening as compared with the morning (- 7.0 %; p < 0.05). Concerning the central command, when extrapolated by the twitch interpolation technique, the decrease in mean activation level of - 6.8 % was consistent with the fluctuation in torque (- 7.0 %). Soleus muscle electromyographic activity (normalized to the M-wave) showed a significant decline (21.6 %; p < 0.001). Moreover, individual changes in MVC percentage were significantly related to those of normalized electromyographic activity of the soleus muscle (r = 0.688; p < 0.01). Thus, it indicated that the subject's capacity to activate the soleus muscle was affected by the time of day. The coactivation level in the tibialis anterior muscle during plantar flexion did not change significantly in the evening. Concerning peripheral mechanisms, we observed a decrease in maximal M-wave amplitude for soleus and gastrocnemii, associated with unchanged single twitch and tetanus torque. To conclude, impairment in soleus muscle central command seemed to be the mechanism in the origin of torque failure. Such information would be of importance in the investigation of day-time fluctuations in complex motor task performances implicating the triceps surae muscle.

Coactivation - neural stimulation - twitch interpolation technique

References

• 1 Allen G M, Gandevia S C, McKenzie D K. Reliability of measurements of muscle strength and voluntary activation using twitch interpolation.  Muscle Nerve. 1995;  18 593-600
• 2 Atkinson G, Coldwells A, Reilly T. A comparison of circadian rhythms in work performance between physically active and inactive subjects.  Ergonomics. 1993;  36 273-281
• 3 Belanger A Y, McComas A J. Extent of motor unit activation during effort.  J Appl Physiol. 1981;  51 1131-1135
• 4 Callard D, Davenne D, Gauthier A, Lagarde D, Van Hoecke J. Circadian rhythms in human muscular efficiency: continuous physical exercise versus continuous rest. A crossover study.  Chronobiol Int. 2000;  17 693-704
• 5 Castaingts V, Martin A, Van Hoecke J, Pérot C. Neuromuscular efficiency of the triceps surae in induced and voluntary contractions: morning and evening evaluations.  Chronobiol Int. 2004;  21 515-527
• 6 Coldwells A, Atkinson G, Reilly T. Sources of variation in back and leg dynamometry.  Ergonomics. 1994;  37 79-86
• 7 De Luca C J. The use of surface electromyography in biomechanics.  J Appl Biomech. 1997;  13 135-163
• 8 Edwards B, Waterhouse J, Atkinson G, Reilly T. Exercise does not influence the phase of the circadian rhythm in temperature in healthy humans.  J Sports Sci. 2002;  20 725-732
• 9 Gandevia S C. Spinal and supraspinal factors in human muscle fatigue.  Physiol Rev. 2001;  81 1725-1789
• 10 Garland S J, Kaufman M P. Role of muscle afferents in the inhibition of motoneurons during fatigue. Gandevia SC, Mc Comas AJ, Enoka RM, Stuart DG, Thomas CK Fatigue: Neural and Muscular Mechanisms. New York; Plenum Press 1995: 271-278
• 11 Gauthier A, Davenne D, Martin A, Cometti G, Van Hoecke J. Diurnal rhythm of the muscular performance of elbow flexors during isometric contractions.  Chronobiol Int. 1996;  13 135-146
• 12 Hamada T, Sale D G, MacDougall J D, Tarnopolsky M A. Postactivation potentiation, fiber type, and twitch contraction time in human knee extensor muscles.  J Appl Physiol. 2000;  88 2131-2137
• 13 Hill D W, Cureton K J, Collins M A, Grisham S C. Diurnal variations in responses to exercise of “morning types” and “evening types”.  J Sports Med Phys Fitness. 1988;  28 213-219
• 14 Horne J A, Ostberg O. A self-assessment questionnaire to determine morningness-eveningness in human circadian rhythms.  Int J Chronobiol. 1976;  4 97-110
• 15 Martin A, Carpentier A, Guissard N, Van Hoecke J, Duchateau J. Effect of time of day on force variation in a human muscle.  Muscle Nerve. 1999;  22 1380-1387
• 16 Merton P A. Voluntary strenght and fatigue.  J Physiol. 1954;  123 553-564
• 17 Moritani T, deVries H A. Neural factors versus hypertrophy in the time course of muscle strength gain.  Am J Phys Med. 1979;  58 115-130
• 18 Pensini M, Martin A, Maffiuletti N A. Central versus peripheral adaptations following eccentric resistance training.  Int J Sports Med. 2002;  23 567-574
• 19 Reilly T, Down A. Investigation of circadian rhythms in anaerobic power and capacity of the legs.  J Sports Med Phys Fitness. 1992;  32 343-347
• 20 Reilly T, Bambaeichi E. Methodological issues in studies of rhythms in human performance.  Biol Rhythm Res. 2003;  34 321-336
• 21 Sale D, Quinlan J, Marsh A, Mc Comas A J, Belanger Y. Influence of joint position on ankle plantar flexion in humans.  J Appl Physiol. 1982;  52 1636-1642
• 22 Taylor D, Gibson H, Edwards R HT, Reilly T. Correction of isometric leg strength tests for time of day.  Eur J Exp Musculoskel Res. 1994;  3 25-27