Influence of weight reduction on physical performance capacity in judokas

Peter Clarys, Kim Ramon, Friso Hagman, Peter Deriemaeker, Evert Zinzen

Research output: Contribution to journalArticle


The purpose of this study was to investigate physical performance capacity in judo players before and after weight reduction. Twenty-two judokas volunteered to take part in the experiment and were tested on two occasions: before and after weight reduction up to competition weight. The subjects were asked to use their own method without giving time limitations or instructions for the weight reduction. Body weight was measured before and after weight reduction, body fat percentage was determined on the two occasions by means of Lohmans equation and two electrical bio-impedance instruments. Food intake before and during the weight reduction period was calculated using the Becel software. The following aspects of physical performance were tested: reaction time, isometric strength and anaerobic endurance. Reaction time was measured by means of a jump test using the Optojump system (Microgate - Italy). Isometric arm strength was measured by tensiometry using a specific 40 seconds procedure. Anaerobic endurance was tested using a repeated jumping procedure. Jumping height was calculated using the Optojump software. During the anaerobic jump test heart rate was recorded (Polar S-810). Body weight was significantly reduced, averaging 2.1 ± 1.97 kg after the weight reduction period. The reduction in body weight was accompanied by a decrease in body fat. Daily energy intake differed significantly when comparing normal intake with energy intake during the weight reduction period. Only the isometric strength, measured during the 3rd maximal effort of the 40s procedure, decreased significantly when comparing values before weight reduction with values after weight reduction (p <0.05). Jump performance (jumping height, contact time) and heart rate as measured during the anaerobic endurance test were not influenced by weight reduction. In conclusion, the subjects were able to decrease body weight and percentage of body fat. Only isometric strength was influenced negatively after weight reduction.
Original languageEnglish
Pages (from-to)71-76
Number of pages6
JournalJournal of Combat Sports and Martial Arts
Issue number2
Publication statusPublished - 2010


  • judo
  • weight reduction
  • weight loss
  • physical performance


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