Rapid weight reduction does not impair athletic performance of Taekwondo athletes – A pilot study

Abstract

In combat sports such as taekwondo (TKD), athletes rapidly reduce body weight to achieve a desired weight category. Competition takes place 16–24 h after weigh-in and thus, the recovery time is an important factor for competition performance. The purpose of this study was to investigate the impact of rapid weight reduction (RWR) on athletic performance and associated hemorheological properties considering relevant recovery time. Five male TKD athletes reduced body weight by 5% within 3½ days. A simulated competition day (SCD) was carried out after a 16 h recovery period. Parameters were measured before RWR, at weigh-in and before and after three TKD simulation matches (SMs) at SCD. Same set-up was conducted but without RWR as control. Basal blood parameters, red blood cells (RBC) deformability and aggregation, serum glucose and fibrinogen were determined. During SMs, heart rate (HRpeak, HRmean), oxygen uptake (VO2peak, VO2mean), peak lactate (Peak La-), difference of lactate (ΔLa) and energy systems (anaerobic-alactic, -lactic and aerobic) were analyzed. Basal blood parameters remained unaltered during the interventions. RBC deformability was reduced and aggregation was increased after RWR but values returned to baseline after recovery and were not affected by the SMs. Glucose level was not affected by the interventions. Kick frequency in SMs was higher after RWR which might be responsible for higher HRpeak, VO2peak, VO2mean, Peak La-, ΔLa- and aerobic demand. The 16 h recovery is sufficient to regenerate measured physiological and hemorheological parameters. TKD-specific performance was not negatively affected during SMs after RWR.

The Current State of Weight-Cutting in Combat Sports

“…The results of laboratory-based trials investigating the effects of weight-cutting on varying aspects of exercise performance are also mixed. Indeed, there is research suggesting that weight-cutting practices negatively influence repeat-effort performance [9,10,13,17,37], while other research indicates no impact on repeat-effort [11,19,20], aerobic [14], and anaerobic performance [38]. It appears that when larger magnitudes (>3% body mass) are lost rapidly (<5 h) using thermal strain, high-intensity exercise performance is impaired [9,13,17].…”

“…It appears that when larger magnitudes (>3% body mass) are lost rapidly (<5 h) using thermal strain, high-intensity exercise performance is impaired [9,13,17]. However, when a similar magnitude of weight is lost over multiple days (2–5) using a combination of methods (food restriction and body-fluid manipulation) laboratory-based trials have failed to observe any negative effect [11,19,20,38]. Studies that report a negative effect of weight-cutting on performance typically observe these effects on high-intensity repeat-effort performance, even up to 24 h following weight loss [9,13,17].…”

“…Within this body of literature, there are conflicting findings on many of the topics mentioned above. For example, studies have indicated that weight-cutting has a negative effect on exercise performance [9,10,13], while other studies have reported no effect [11,19,20]. The limited volume of literature across a range of topics within weight-cutting precludes a comprehensive systematic review which would use a highly technical, specific methodological approach to identify and appraise evidence on weight-loss practices in different combat sports [21].…”

Rapid Weight Loss in Congolese Judo: Energy Profile, Performance and Haematological Effects

“…a difference of 5%; p < 0.05, Figure 3). In the only study that we identified in the literature in combat sports athletes subjected to RWL, that of Yang et al (2018) devoted to taekwondo, the authors note at the end of the series of fights (5 fights per series and a number of 3 series) values of: 179.6 ± 10.9 bpm at the end of the first series Advances in Physical Education (maximum: 193.3 ± 8.3 bpm), 176.8 ± 8.7 bpm in the second set (maximum:…”

“…The first limitation is the assessment of energy expenditure. It would have been desirable to separately determine the aerobic, anaerobic lactic and anaerobic alactic systems by the consumption of O 2 during a session, combined with measurements of maximum lactate concentration and the fast of excess oxygen uptake after exercise (EPOCFAST), as suggested by a recent study of Yang et al (2018). However, the implementation of these methods is proving difficult in the context of the poor technical facilities of our biological analysis laboratories.…”