ORIGINAL ARTICLE  EXERCISE PHYSIOLOGY AND BIOMECHANICS 

The Journal of Sports Medicine and Physical Fitness 2018 March;58(3):249-55

DOI: 10.23736/S0022-4707.17.06615-4

Copyright © 2017 EDIZIONI MINERVA MEDICA

language: English

Performance of muscle strength and fatigue tolerance in young trained women supplemented with caffeine

Carlos A. FETT ^{1, 2, 3} ✉, Natalia M. AQUINO ¹, Jairo SCHANTZ JUNIOR ^{1, 2}, Camila F. BRANDÃO ^{1, 4}, Joás D. de ARAÚJO CAVALCANTI ¹, Waleria C. FETT ^{1, 2}

¹ Center for Research on Physical Fitness, Computers, Metabolism, Sport and Health (NAFIMES) of the Federal University of Mato Grosso, Cuiabá, Brazil; ² Postgraduate Strict Sense of Physical Education, Faculty of Physical Education, Federal University of Mato Grosso, Cuiabá, Brazil; ³ Postgraduate Strict Sense Health Sciences, School of Medicine, Federal University of Mato Grosso, Cuiabá, Brazil; ⁴ Postgraduate Strict Sense of Medical Sciences, Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil

BACKGROUND: The aim of this paper was to verify the effect of caffeine supplementation on the muscular strength and fatigue tolerance of young trained women.
METHODS: Eight women of 25±5-years-old, who had undergone a minimum of 12 months of continuous resisted training, Body Mass Index 20-23 kg/m2 were submitted to 4 tests: One Repetition Maximum (1-RM, kg) to pull down (PD), Hack Squat (HS), Bench Press (BP), and Knee Extension Exhaustion (drop-set, 100/80/60 kg, repetitions) (DS). They performed the tests in 4 consecutive blocks one-week apart crossover system: basal without caffeine (B); first caffeine (C1); placebo with starch supplementation (P); second caffeine (C2). Caffeine supplementation 6 mg.kg-1 30 minutes before. The paired t-test and repeated ANOVA with Tukey-Kramer were performed.
RESULTS: Respectively for B, C1, P and C2 to each test were PD (52, 54, 56, 55, P>0.05); HS (99, 109, 108, 121*; P<0.001); BP (22, 26*, 25*, 27*; P<0.05); DS (28, 35*,**, 30*, 37**; P<0.001). To comparison of B, P and mean caffeine (C1+C2/2) results respectively were: HS (99, 108*, 115***; P<0.05); BP (22, 25*, 26*; P<0.05); DS (28, 30#, 36**; P<0.01 and P<0.001). The delta ([C1+C2/2]-[B+P/2]) were PD=0 (P>0.05), HS=12 (P=0.04), BP=3 (P=0.007), DS=7 (P=00.1).
CONCLUSIONS: Caffeine improved tolerance to exhaustion and has tendency to improve strength in this young women. Probably caffeine supplementation is useful to improve performance in women engaged in sports with these physical valences. An investigation with a major numbers of volunteers could elucidate some controversies observed here.

KEY WORDS: Muscle strength - Physical fitness - Fatigue - Caffeine