Effects of acute and chronic weight loss of taekwondo players on RER, heart rate and strength.

Abstract

Kwon, Y. W. Effects of acute and chronic weight loss of taekwondo players on RER, heart rate and strength. Exercise Science. 20(3): [319][320][321][322][323][324][325][326][327][328] 2011. The purpose of this study was to investigate the effects of rapid and gradual weight loss (6%) on RER, heart rate and strength of athletes. Twenty male Taekwondo players participated in this study and were divided to rapid (RW, n=10) and gradual weight loss group (GW, n=10). RW group reduced their body weight for 3day by fluid and energy restriction and forced sweating by souna and exercise. GW group reduced their weight for 14day by energy restriction and exercise. Exercise sessions took place on a treadmill performing 4 minutes of running to reach targeted intensity (75% HRmax) and continued during 30 minutes. After 30 minutes, work rate was gradually increased (0.9 mile per hour every 3 minutes, 2% degree elevation) until exhaustion. RER and heart rate were measured before, during (30minutes) and immediately after an incremental treadmill test to exhaustion. Muscle strength was measured from pre and post body weight loss. RER significantly increased with exercise and this exercise induced increase was lower RW group than GW group. Acute and chronic weight loss increased heart rate with exercise but their were any significant different with RW and GW. Back and grip strength did not show any significant change with weight loss, but sit up decreased significantly after rapid weight loss. In conclusion, rapid weight loss enhanced fatty acid utilization and decreased muscle strength of taekwondo player. Further study needed to elucidate the exact mechanism related to glycolytic and oxydative enzyme change with acute and chronic weight loss.