title: Effect of Kaempferia parviflora Extract on Physical Fitness of Soccer Players: A Randomized Double-Blind Placebo-Controlled Trial.
abstract: BACKGROUND
  Physical fitness is a fundamental prerequisite for soccer players. Kaempferia parviflora is an herbal plant that has been used in some Asian athletes with the belief that it might prevent fatigue and improve physical fitness. This study aimed to determine the effects of Kaempferia parviflora on the physical fitness of soccer players.
  
  
  METHODS
  Sixty soccer players who routinely trained at a sports school participated in a double-blind placebo-controlled trial and were randomly allocated to the treatment group or the placebo group. The participants in both groups were given either 180 mg of Kaempferia parviflora extract in capsules or a placebo once daily for 12 weeks. Baseline data were collected using the following 6 tests of physical performance: a sit-and-reach test, a hand grip strength test, a back-and-leg strength test, a 40-yard technical test, a 50-metre sprint test, and a cardiorespiratory fitness test. All of the tests were performed every 4 weeks throughout the 12-week study period.
  
  
  RESULTS
  The study showed that after treatment with Kaempferia parviflora, the right-hand grip strength was significantly increased at weeks 4, 8, and 12. The left-hand grip strength was significantly increased at week 8. However, the back-and-leg strength, the 40-yard technical test, the sit-and-reach test, the 50-metre sprint test, and the cardiorespiratory fitness test results of the treatment group were not significantly different from those of the placebo group.
  
  
  CONCLUSIONS
  Taking Kaempferia parviflora supplements for 12 weeks may significantly enhance some physical fitness components in soccer players.
authors.affiliation: Division of Exercise and Sport sciences Graduate School, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Kreeta
authors.initials: K
authors.lastname: Promthep
authors.affiliation: Back, Neck, Other Joint Pain, and Human Performance Research Center, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Wichai
authors.initials: W
authors.lastname: Eungpinichpong
authors.affiliation: Center for Research and Development of Herbal Health Products, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Bungorn
authors.initials: B
authors.lastname: Sripanidkulchai
authors.affiliation: Back, Neck, Other Joint Pain, and Human Performance Research Center, Khon Kaen University, Khon Kaen, Thailand.
authors.forename: Uraiwan
authors.initials: U
authors.lastname: Chatchawan
mesh_terms: D000293:Adolescent; D000410:Alanine Transaminase / Q000097:blood; D000469:Alkaline Phosphatase / Q000097:blood; D000704:Analysis of Variance; D001219:Aspartate Aminotransferases / Q000097:blood; D054874:Athletic Performance / Q000502:physiology*; D001774:Blood Chemical Analysis; D001806:Blood Urea Nitrogen; D001837:Body Weights and Measures; D003404:Creatinine / Q000097:blood; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008297:Male; D010809:Physical Fitness / Q000502:physiology*; D010936:Plant Extracts / Q000494:pharmacology*; D012916:Soccer / Q000502:physiology*; D030521:Zingiberaceae / Q000737:chemistry*
chemical_list: D010936:Plant Extracts; D003404:Creatinine; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D000469:Alkaline Phosphatase