ORIGINAL ARTICLE  EXERCISE PHYSIOLOGY AND BIOMECHANICS 

The Journal of Sports Medicine and Physical Fitness 2019 February;59(2):223-9

DOI: 10.23736/S0022-4707.17.08106-3

Copyright © 2017 EDIZIONI MINERVA MEDICA

language: English

Caffeine, acute static stretching and maximum knee flexion strength

Tyler M. FARNEY ^{1, 2} ✉, Arnold G. NELSON ², Joke KOKKONEN ³

¹ Department of Health and Kinesiology, Texas A&M University - Kingsville, Kingsville, TX, USA; ² School of Kinesiology, Louisiana State University, Baton Rouge, LA, USA; ³ Department of Exercise and Sport Science, Brigham Young University - Hawaii, Laie, HI, USA

BACKGROUND: Reductions in one-repetition maximum lifts (1RM) following static stretching can be attributed to enhanced neural inhibition, which can be reduced by using stimulants like caffeine. This study compared knee-flexion 1RM following either static stretching (SS) or no-stretching (NS), as well as after ingesting either caffeine (C) or placebo (P).
METHODS: Twenty-four participants (12 female, 12 male) performed four random counterbalanced knee flexion 1RM tests. A 1RM test was performed for each condition at the same time of day with ~48 hours separating each test. Static stretching consisted of 5 exercises with the 1RM being performed immediately following the stretching. Caffeine dose was 6 mg/kg body weight, and the placebo was methylcellulose (520 mg). Both doses were administered as pills 60 minutes before the SS or NS procedures.
RESULTS: Two-way repeated measures ANOVA showed a significant main effect for NS vs. SS (P<0.001, ηG2=0.23). The main effect for C vs. P, and the interaction between C vs. P and NS vs. SS were not statistically different. Average 1RMs were: CNS = 512±242 N, CSS = 474±241 N, PNS = 498±247 N, and PSS = 460±247 N.
CONCLUSIONS: It is concluded that static stretching induced strength decrements are not removed by using stimulants at doses allowed by sport governing organizations.

KEY WORDS: Articular range of motion - Muscle strength - Neural inhibition - Centrale nervous system stimulants