Changes Of Body Composition And Anaerobic Performance After Rapid Weight Loss In Taekwondo Players

Introduction
In general, most athletes participating in sports with specific weight categories have been used to rapid weight loss
through energy restriction and dehydration, in order to compete in a lower weight category [1]. Rapid weight loss can
decrease muscular function and high-intensity performance in wrestling, judo, and boxing, but this has not always been
a consistent finding [2,3]. And it could not be suggested the similar effects of rapid weight loss on the physical and
physiological responses between two weight groups, as specific body composition showed a significant difference
between heavy weight and light weight class. This study examined the difference of changes on body composition and
anaerobic high-intensity performance after rapid weight loss following a different weight class in male taekwondo
players.

Methods
Subjects were consisted of 20-aged male taekwondo players, and were divided to three groups as heavy weight group
(n=6, BW; 98.02±4.81 kg, %fat; 26.73±4.24 %), light weight group (n=6, BW; 68.35±5.42 kg, %fat; 14.75±3.80 %),
and control group (n=6, BW; 64.12±4.87 kg, %fat; 22.83±2.86 %). Subjects of heavy and light weight groups were
asked to reduce their body weight by 5% during 3 days, and the weight cutting was chosen by the energy restriction (2
times/day, 18 kcal/kg , diet composition : CHO 60 %, Fat 25 %, Protein 15 %) and sauna (2 times/day, 15 mins, 74-
79), and was given a refeeding diet (45 kcal/kg) after rapid weight loss. Body weight, body fat, body circumferences,
and skinfold thickness were measured during weight loss intervention. Anaerobic performance test was tested three
times : before rapid weight loss, immediately after rapid weight loss, and following refeeding diet of recovery after
rapid weight loss. These tests were performed the supramaximal exercise on bicycle ergometer (0.04 kp/kg BW, 3
mins-3 round, 1 min interval), and were measured the mean power output, peak power output, heart rate, and blood
lactate concentration.

Results
In body circumferences, heavy weight group significantly (p<.05) decreased forearm, thorax, waist, hip, thigh, and calf,
but light weight group showed the significant (p<.05) changes of only forearm and waist as compared to prior rapid
weight loss. Skinfold thickness of abdomen and suprailiac crest significantly (p<.05) decreased in both groups, but
heavy weight group showed an additional change of biceps brachii. In anaerobic high-intensity exercise test, light
weight group showed a significant (p<.05) decrease of peak power output after rapid weight loss as compared to prior
weight loss, but heavy weight group showed no significant change of power output after rapid weight loss.

Discussion / Conclusions
We found a significant change of body composition in central region after rapid weight loss through energy
restriction and sauna, and it could be suggested the compound change of skinfold and muscle by the preferential
change of body circumferences as compared to body fat. Although body composition showed a significant change
in heavy weight group, light weight group showed a serious depression of anaerobic high-intensity performance. In
these results, we could be suggested that light weight group was asked a more careful attention on the negative
effects of energy restriction and dehydration in rapid weight loss.

References
[1]. Webster, S., et al. (1990). Med. Sci. Spt. Exerc., 22(2), 229-234.
[2]. Roemmich, J.N., & Sinning, W.E. (1996). Int. J. Sports Med., 17(2), 92-99.
Fig. 1. Changes of peak power output of anaerobic performance test in rapid weight loss and refeeding of three groups.
[3]. Greiwe, J.S., et al. (1998). Med. Sci. Spt. Exerc., 30(2), 284-288.

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