title: Somatosensory feedback from the limbs exerts inhibitory influences on central neural drive during whole body endurance exercise.
abstract: We investigated whether somatosensory feedback from contracting limb muscles exerts an inhibitory influence on the determination of central command during closed-loop cycling exercise in which the subject voluntarily determines his second-by-second central motor drive. Eight trained cyclists performed two 5-km time trials either without (5K(Ctrl)) or with lumbar epidural anesthesia (5K(Epi); 24 ml of 0.5% lidocaine, vertebral interspace L(3)-L(4)). Percent voluntary quadriceps muscle activation was determined at rest using a superimposed twitch technique. Epidural lidocaine reduced pretime trial maximal voluntary quadriceps strength (553 +/- 45 N) by 22 +/- 3%. Percent voluntary quadriceps activation was also reduced from 97 +/- 1% to 81 +/- 3% via epidural lidocaine, and this was unchanged following the 5K(Epi), indicating the presence of a sustained level of neural impairment throughout the trial. Power output was reduced by 9 +/- 2% throughout the race (P < 0.05). We found three types of significant effects of epidural lidocaine that supported a substantial role for somatosensory feedback from the exercising limbs as a determinant of central command throughout high-intensity closed-loop cycling exercise: 1) significantly increased relative integrated EMG of the vastus lateralis; 2) similar pedal forces despite the reduced number of fast-twitch muscle fibers available for activation; 3) and increased ventilation out of proportion to a reduced carbon dioxide production and heart rate and increased blood pressure out of proportion to power output and oxygen consumption. These findings demonstrate the inhibitory influence of somatosensory feedback from contracting locomotor muscles on the conscious and/or subconscious determination of the magnitude of central motor drive during high intensity closed-loop endurance exercise.
authors.affiliation: John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin-Madison Medical School, Madison, Wisconsin, USA. markus.amann@physiol.biol.ethz.ch
authors.forename: Markus
authors.initials: M
authors.lastname: Amann
authors.forename: Lester T
authors.initials: LT
authors.lastname: Proctor
authors.forename: Joshua J
authors.initials: JJ
authors.lastname: Sebranek
authors.forename: Marlowe W
authors.initials: MW
authors.lastname: Eldridge
authors.forename: David F
authors.initials: DF
authors.lastname: Pegelow
authors.forename: Jerome A
authors.initials: JA
authors.lastname: Dempsey
mesh_terms: D000328:Adult; D000344:Afferent Pathways / Q000502:physiology*; D000465:Algorithms; D000767:Anesthesia, Epidural; D000779:Anesthetics, Local / Q000494:pharmacology; D001642:Bicycling / Q000502:physiology*; D002490:Central Nervous System / Q000502:physiology*; D004576:Electromyography; D015444:Exercise / Q000502:physiology*; D005121:Extremities / Q000294:innervation / Q000502:physiology*; D005246:Feedback / Q000502:physiology*; D006801:Humans; D008012:Lidocaine / Q000494:pharmacology; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects / Q000294:innervation / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D011659:Pulmonary Gas Exchange / Q000502:physiology; D015203:Reproducibility of Results; D015656:Respiratory Mechanics / Q000502:physiology; D055815:Young Adult
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine
references.citation: Am J Physiol Regul Integr Comp Physiol. 2007 Mar;292(3):R1279-86
references.pmid: 17122329
references.citation: Sports Med. 2003;33(1):1-11
references.pmid: 12477374
references.citation: Anesth Analg. 1986 Apr;65(4):325-9
references.pmid: 3954107
references.citation: Br J Anaesth. 1975 Feb;47 suppl:199-211
references.pmid: 1096918
references.citation: J Appl Physiol (1985). 1999 Apr;86(4):1367-73
references.pmid: 10194224
references.citation: J Appl Physiol (1985). 2004 Dec;97(6):2035-41
references.pmid: 15286050
references.citation: Acta Physiol Scand. 1996 Apr;156(4):429-34
references.pmid: 8732247
references.citation: J Appl Physiol (1985). 2002 Mar;92(3):1317-24
references.pmid: 11842073
references.citation: Anesthesiology. 1964 Nov-Dec;25:752-9
references.pmid: 14225977
references.citation: J Appl Physiol (1985). 2005 Jan;98(1):120-31
references.pmid: 15377649
references.citation: J Physiol. 1913 Oct 17;47(1-2):112-36
references.pmid: 16993229
references.citation: Anesthesiology. 1990 Apr;72(4):711-34
references.pmid: 2157353
references.citation: Acta Physiol Scand. 1998 Mar;162(3):275-83
references.pmid: 9578373
references.citation: Med Sci Sports Exerc. 2004 Apr;36(4):613-22
references.pmid: 15064589
references.citation: Respir Physiol. 1985 Mar;59(3):313-37
references.pmid: 3992065
references.citation: Am J Physiol Regul Integr Comp Physiol. 2007 Jan;292(1):R598-606
references.pmid: 16959862
references.citation: Eur J Pharm Sci. 2000 Dec;12(2):125-31
references.pmid: 11102740
references.citation: Eur J Appl Physiol Occup Physiol. 1999 Jun;80(1):57-63
references.pmid: 10367724
references.citation: Am J Physiol Regul Integr Comp Physiol. 2007 Nov;293(5):R2036-45
references.pmid: 17715180
references.citation: Clin Sci (Lond). 2000 Mar;98(3):329-37
references.pmid: 10677392
references.citation: Muscle Nerve. 2002 Nov;26(5):708-12
references.pmid: 12402294
references.citation: J Appl Physiol (1985). 1997 Jun;82(6):1811-7
references.pmid: 9173945
references.citation: Anesth Analg. 1992 Dec;75(6):906-21
references.pmid: 1443710
references.citation: Electroencephalogr Clin Neurophysiol. 1985 Feb;60(2):130-4
references.pmid: 2578364
references.citation: J Appl Physiol (1985). 2008 May;104(5):1541-2
references.pmid: 18239081
references.citation: J Physiol. 2008 Jan 1;586(1):161-73
references.pmid: 17962334
references.citation: J Physiol. 1990 Jan;420:281-93
references.pmid: 2324985
references.citation: J Physiol. 2007 May 15;581(Pt 1):389-403
references.pmid: 17317739
references.citation: J Physiol. 2006 Aug 1;574(Pt 3):905-15
references.pmid: 16497719
references.citation: J Physiol. 2008 Mar 1;586(5):1277-89
references.pmid: 17884925
references.citation: J Physiol. 2002 Apr 15;540(Pt 2):681-9
references.pmid: 11956354
references.citation: J Physiol. 1998 Mar 1;507 ( Pt 2):619-28
references.pmid: 9518719
references.citation: Anesthesiology. 2004 Jun;100(6):1504-10
references.pmid: 15166571
references.citation: J Neurophysiol. 1987 Jul;58(1):125-37
references.pmid: 3039078
references.citation: J Appl Physiol Respir Environ Exerc Physiol. 1984 Aug;57(2):507-13
references.pmid: 6432755
references.citation: J Physiol. 1954 Mar 29;123(3):553-64
references.pmid: 13152698
references.citation: J Physiol. 1992 Mar;448:551-63
references.pmid: 1593477
references.citation: J Appl Physiol. 1976 Jan;40(1):12-6
references.pmid: 1248977
references.citation: J Physiol. 1993 Oct;470:693-704
references.pmid: 8308750
references.citation: Acta Physiol Scand Suppl. 1996;634:1-27
references.pmid: 8876756
references.citation: Pflugers Arch Gesamte Physiol Menschen Tiere. 1959;269:613-21
references.pmid: 14428236
references.citation: J Physiol. 2007 Dec 15;585(Pt 3):919-21; author reply 923-4
references.pmid: 17962324
references.citation: Annu Rev Physiol. 1983;45:229-42
references.pmid: 6342515
references.citation: J Appl Physiol (1985). 2006 Jul;101(1):119-27
references.pmid: 16497836
references.citation: Anesthesiology. 1989 May;70(5):851-8
references.pmid: 2719320
references.citation: Am J Physiol. 1991 Aug;261(2 Pt 1):E214-20
references.pmid: 1872383
references.citation: J Appl Physiol (1985). 1998 Jan;84(1):344-50
references.pmid: 9451655
references.citation: Physiol Rev. 1994 Jan;74(1):49-94
references.pmid: 8295935
references.citation: Am J Physiol. 1989 Jul;257(1 Pt 1):E95-101
references.pmid: 2546439
references.citation: J Physiol. 1989 Oct;417:13-24
references.pmid: 2621589
references.citation: J Appl Physiol Respir Environ Exerc Physiol. 1983 Jul;55(1 Pt 1):105-12
references.pmid: 6309712
references.citation: J Physiol. 1986 Oct;379:451-9
references.pmid: 3560001
references.citation: J Physiol. 1987 Aug;389:557-68
references.pmid: 3681737
references.citation: J Appl Physiol (1985). 2004 Jul;97(1):188-96
references.pmid: 15064300
references.citation: Eur J Appl Physiol Occup Physiol. 1999 Nov-Dec;80(6):555-63
references.pmid: 10541922
references.citation: Science. 1981 Feb 20;211(4484):844-6
references.pmid: 7466362
references.citation: J Appl Physiol (1985). 1988 Jun;64(6):2306-13
references.pmid: 3136123
references.citation: J Appl Physiol (1985). 2004 Apr;96(4):1486-95
references.pmid: 15016793
references.citation: J Physiol. 1989 Jun;413:433-45
references.pmid: 2600859
references.citation: J Physiol. 2001 Jun 15;533(Pt 3):823-36
references.pmid: 11410638
references.citation: Eur J Appl Physiol Occup Physiol. 1996;74(1-2):114-8
references.pmid: 8891509
references.citation: J Appl Physiol (1985). 2006 Mar;100(3):1077-9
references.pmid: 16467394
references.citation: J Appl Physiol (1985). 1992 May;72(5):1631-48
references.pmid: 1601767
references.citation: Physiol Rev. 2001 Oct;81(4):1725-89
references.pmid: 11581501
references.citation: Circulation. 2003 Apr 29;107(16):2127-33
references.pmid: 12695298
references.citation: Arch Phys Med Rehabil. 1983 Sep;64(9):417-20
references.pmid: 6615179
references.citation: J Physiol. 1993 Oct;470:681-91
references.pmid: 8308749
references.citation: Am J Physiol Regul Integr Comp Physiol. 2005 Aug;289(2):R441-R449
references.pmid: 15860645
references.citation: J Appl Physiol (1985). 2008 Mar;104(3):861-70
references.pmid: 17962570
references.citation: J Physiol. 2006 Sep 15;575(Pt 3):937-52
references.pmid: 16793898
references.citation: Circ Res. 1995 Jan;76(1):127-31
references.pmid: 8001270
references.citation: J Physiol. 1977 May;267(1):75-88
references.pmid: 141496
references.citation: J Neurosci. 2003 Sep 3;23(22):7974-80
references.pmid: 12954858
references.citation: Exp Brain Res. 1978 Apr 14;31(4):511-22
references.pmid: 658178
references.citation: Prog Neurobiol. 2004 Mar;72(4):223-61
references.pmid: 15142684
references.citation: J Physiol. 2003 Sep 15;551(Pt 3):1013-21
references.pmid: 12819303
references.citation: Circ Res. 1989 Aug;65(2):468-76
references.pmid: 2752552
references.citation: Med Sci Sports Exerc. 2008 Mar;40(3):574-8
references.pmid: 18379223
references.citation: Acta Physiol Scand. 1965 Mar;63:343-50
references.pmid: 14324070
references.citation: Med Sci Sports Exerc. 2003 Apr;35(4):589-94
references.pmid: 12673141
references.citation: Am J Physiol. 1999 Jul;277(1):R76-85
references.pmid: 10409260