No effect of prior caffeine ingestion on neuromuscular recovery after maximal fatiguing contractions.
The purpose of this study was to test the hypothesis that prior caffeine ingestion would enhance neural recovery after isometric fatiguing maximal intermittent plantar flexions, and thus would enhance the recovery of voluntary muscle strength. After a familiarisation session, 13 males randomly participated in two experimental trials where they ingested either caffeine (approximately 6 mg/kg) or identical placebo pills 1 h prior to testing. Subjects were tested for electromyogram (EMG) activity and evoked V-waves in the soleus and gastrocnemius medialis muscles. These measurements were obtained during brief plantar flexion maximum voluntary isometric contractions (MVICs), and normalised by the superimposed maximal M-wave (EMG/M(SUP) and V/M(SUP), respectively), before and after (20 s, 10 min and 20 min) a fatigue protocol (seven 25 s MVICs, 5 s rest). There were no effects (P > 0.05) of caffeine ingestion on EMG/M(SUP), V/M(SUP), MVIC or M(SUP). The central neural modulation (EMG/M(SUP) and V/M(SUP)) and voluntary strength changes followed a similar time-course with a substantial reduction 20 s post-fatigue and a gradual return towards baseline values.
Fimland
Marius S
MS
Department of Circulation and Imaging, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway. marius.fimland@ntnu.no
Helgerud
Jan
J
Knutsen
Andreas
A
Ruth
Helge
H
Leivseth
Gunnar
G
Hoff
Jan
J
D000818:Animals; D002110:Caffeine / Q000494:pharmacology*; D004576:Electromyography / Q000379:methods; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D018763:Muscle Fatigue / Q000187:drug effects / Q000502:physiology; D053581:Muscle Strength Dynamometer; D010807:Physical Endurance / Q000502:physiology; D005082:Physical Exertion / Q000187:drug effects* / Q000502:physiology
D002110:Caffeine