The Effect Of Rapid Time Zone Travel By Airplane On Circadian Rhythms In Elite Karate Athletes Competing In The 13th Funakoshi Cup In Tokyo, Japan

Abstract

PURPOSE: Rapid travel across multiple time zones (RTZ) may cause disturbances to zeitgebers regulating the internal body clock. Little is known about the effects of RTZ on amateur Karate athletes who compete internationally. Two thousand elite, national championship amateur Karate athletes from 53 countries participated in the 13th Funakoshi Cup, in Tokyo, Japan in October, 2014. This study used a convenience sample of 11 athletes (who competed on the U.S. team to evaluate the effects of RTZ over the 3-days prior to competition. METHODS: Athletes (female = 6; 17.9 ± 9.6 training years; male = 5; 24.6 ± 9.3 training years) arrived in Tokyo four days prior to tournament eliminations for adaptation to the novel environment. All met daily to stretch and train lightly. Prior to training each day, data were collected on left and right handgrip strength via dynamometry, oral temperature, and self-perception of sleep quality from the previous night using the method of Reilly, Atkinson, & Waterhouse, 1997. Data were analyzed with SPSS version 31 software. RESULTS: Over the 3-day training period hand grip strength did not change for either men (right hand: P > .301; left hand: P > .932) or women (right hand: P > .905; left hand: P > .169). Sleep quality improved (men: P > .326: D1 = 3.8 ± 2.2, D2 = 2.4 ± 1.1, D3 = 2.8 ± 1.3); women P > .357: D1 = 3.0 ± 1.7, D2 = 2.17 ± 1.5, D3 = 2.6 ± 1.0), but not significantly. Pearson correlation analysis showed a significant relationship between average sleep quality and right, but not left, handgrip strength in women (right r = .863: P < .026; left r = .169: P > .179). Average sleep quality and handgrip strength in men showed a moderate relationship (left hand r = .762: P > .134; right hand r = .670: P > .216). CONCLUSIONS: In this small sample of amateur, elite Karate athletes sleep quality appeared to be negatively affected by RTZ. Adequate and timely sleep may influence activities such as handgrip dynamometry that mimic the rapid decision making and reflexive actions that are common in international Karate competition. Our findings suggest that more research with larger samples is needed in this sport venue.