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Muscle contractile function and neural control after repetitive endurance cycling.

Ross, EZ, Gregson, W, Williams, K, Robertson, C and George, K (2010) Muscle contractile function and neural control after repetitive endurance cycling. Med Sci Sports Exerc, 42 (1). pp. 206-212.

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Abstract

PURPOSE: To examine alterations in muscle contractile properties, cortical excitability, and voluntary activation as a consequence of 20 d of repetitive endurance cycling within a 22-d period. METHODS: Eight well-trained male cyclists completed 20 prolonged cycling stages interspersed by two rest days (days 9 and 17), which replicated the 2007 Tour de France route and schedule. Isometric knee extensor torque and EMG responses of the vastus lateralis in response to percutaneous electrical stimulation and transcranial magnetic stimulation were measured before, on days 9 and 17, and 2 d after completion of Tour de France. Postexercise measurements on days 9 and 17 were taken >18 h after cessation of the previous exercise bout. RESULTS: Maximal voluntary contraction of the knee extensors decreased by 20 +/- 10% (P < 0.01) during Tour de France but recovered after 2 d of rest. Peripherally evoked M-wave and potentiated twitch responses were also significantly decreased during Tour de France, up to 31 +/- 21% and 22 +/- 18%, respectively (P < 0.05), but returned to baseline values after 2 d of recovery. Voluntary activation was reduced to 75 +/- 8% (P < 0.05) during Tour de France and remained significantly depressed (79 +/- 7%, P < 0.05) after completion. The amplitude of motor evoked potentials was decreased by 44 +/- 28% (P < 0.01) on day 9 and remained significantly depressed during the remainder of, and after, Tour de France. CONCLUSIONS: A reduction in knee extensor strength, which occurs after repetitive prolonged cycling exercise, is a result of both central and peripheral processes. Reduced sarcolemmal excitability and impairment of contractile mechanisms exists even after 18 h of recovery. An enduring reduction in corticomotor output persists even after 2 d of rest.

Item Type: Article
Authors :
NameEmailORCID
Ross, EZUNSPECIFIEDUNSPECIFIED
Gregson, WUNSPECIFIEDUNSPECIFIED
Williams, Kk.williams@surrey.ac.ukUNSPECIFIED
Robertson, CUNSPECIFIEDUNSPECIFIED
George, KUNSPECIFIEDUNSPECIFIED
Date : January 2010
Identification Number : https://doi.org/10.1249/MSS.0b013e3181b07a18
Uncontrolled Keywords : Adult, Analysis of Variance, Bicycling, Electric Stimulation, Electromyography, Heart Rate, Humans, Knee Joint, Male, Muscle Contraction, Muscle, Skeletal, Oxygen Consumption, Physical Endurance, Torque, Transcranial Magnetic Stimulation
Related URLs :
Depositing User : Symplectic Elements
Date Deposited : 17 May 2017 09:32
Last Modified : 17 May 2017 09:32
URI: http://epubs.surrey.ac.uk/id/eprint/824158

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