Craig A. Bridge

Physical and Physiological Profiles of Taekwondo Athletes

Taekwondo has evolved into a modern-day Olympic combat sport. The physical and physiological demands of modern-day taekwondo competition require athletes to be competent in several aspects of fitness. This review critically explores the physical and physiological characteristics of taekwondo athletes and presents implications for training and research. International taekwondo athletes possess low levels of body fat and a somatotype that characterises a blend of moderate musculoskeletal tissue and relative body linearity. While there is some variation in the maximum oxygen uptake of taekwondo athletes, moderate to high levels of cardio-respiratory fitness are necessary to support the metabolic demands of fighting and to facilitate recovery between consecutive matches. Taekwondo athletes demonstrate high peak anaerobic power characteristics of the lower limbs and this attribute appears to be conducive to achieving success in international competition. The ability to generate and sustain power output using both concentric and ‘stretch-shortening cycle’ muscle actions of the lower limbs may be important to support the technical and tactical actions in combat. Taekwondo competitors also display moderate to high maximum dynamic strength characteristics of the lower and upper extremities, and moderate endurance properties of the trunk and hip flexor musculature. The dynamic nature of the technical and tactical actions in the sport demand high flexibility of the lower limbs. More extensive research is required into the physical and physiological characteristics of taekwondo athletes to extend existing knowledge and to permit specialised conditioning for different populations within the sport.

Heart rate responses to taekwondo training in experienced practitioners

The purpose of this study was to evaluate the heart rate (HR) responses of specific Taekwondo training activities, practiced by experienced practitioners in a natural training environment. Eight male experienced Taekwondo practitioners, with 3–13 years (5.4 ± 3.2 years) experience took part in a 5-day Taekwondo training camp. Continuous HR measures were recorded at 5-second intervals during 6 training sessions; each session was observed and notated, and a diary of training activities was recorded. The HR responses were assimilated into 8 fundamental training activities for analysis: elastics, technical combinations, step sparring, pad work, forms, basic techniques and forms, sparring drills, and free sparring. Taekwondo training elicited HR into 64.7–81.4% of HR maximum (%HRmax). Moderate relative exercise intensities (64.7–69.4%HRmax) were elicited by elastics, technical combinations, and step sparring. The remaining 5 training activities elicited hard relative exercise intensities (74.7–81.4%HRmax). One-way repeated-measures analysis of variance with post hoc analysis revealed that elastics, technical combinations, and step sparring elicited significantly lower relative intensities than the remaining training activities (p > 0.05). Furthermore, forms, basic techniques and forms, sparring drills, and free sparring elicited significantly higher relative intensities than the remaining training activities (p > 0.05). In conclusion, all Taekwondo training activities in this study seemed suitable for cardiovascular conditioning, although different training activities stressed the cardiovascular system to different degrees. Practically, this suggests coaches need to structure Taekwondo training sessions based not only on the technical and tactical needs of practitioners but also in a manner that enables sufficient cardiovascular conditioning for competition.

Physiological and Psychological Effects of Deception on Pacing Strategy and Performance: A Review

The aim of an optimal pacing strategy during exercise is to enhance performance whilst ensuring physiological limits are not surpassed, which has been shown to result in a metabolic reserve at the end of the exercise. There has been debate surrounding the theoretical models that have been proposed to explain how pace is regulated, with more recent research investigating a central control of exercise regulation. Deception has recently emerged as a common, practical approach to manipulate key variables during exercise. There are a number of ways in which deception interventions have been designed, each intending to gain particular insights into pacing behaviour and performance. Deception methodologies can be conceptualised according to a number of dimensions such as deception timing (prior to or during exercise), presentation frequency (blind, discontinuous or continuous) and type of deception (performance, biofeedback or environmental feedback). However, research evidence on the effects of deception has been perplexing and the use of complex designs and varied methodologies makes it difficult to draw any definitive conclusions about how pacing strategy and performance are affected by deception. This review examines existing research in the area of deception and pacing strategies, and provides a critical appraisal of the different methodological approaches used to date. It is hoped that this analysis will inform the direction and methodology of future investigations in this area by addressing the mechanisms through which deception impacts upon performance and by elucidating the potential application of deception techniques in training and competitive settings.

Taekwondo Exercise Protocols do not Recreate the Physiological Responses of Championship Combat

The aim of this study was to determine the external validity of Taekwondo-specific exercise protocols. 10 male international Taekwondo competitors (age 18±2 years) took part in a championship combat and an exercise protocol that simulated the activity pattern of Taekwondo combat. Heart rate and venous blood samples were obtained in both settings. Despite similarity in the activity profiles, the championship Taekwondo combats elicited higher (p<0.05) heart rate (188±8 beats.min - 1), plasma lactate (12.2±4.6 mmol.L - 1), glucose (10.3±1.1 mmol.L - 1), -glycerol (143.4±49.4 µmol.L - 1), -adrena-line (2.7±1.7 nmol.L - 1) and noradrenaline (14.3±9.4 nmol.L - 1) responses than the -Taekwondo exercise protocol (heart rate: 172±4 beats.min - 1; plasma lactate: 3.6±2.7 mmol.L - 1; glucose: 5.9±0.8 mmol.L - 1; glycerol: 77.7±21.3 µmol.L - 1; adrenaline: 0.6±0.2 nmol.L - 1 and noradrenaline: 3.0±1.1 nmol.L - 1). This discrepancy in the physiological responses appeared to be mediated by a reduced stress response in the Taekwondo exercise protocol. These findings suggest that Taekwondo-specific exercise protocols are not appropriate to study the physiological demands of Taekwondo. -Strategies designed to increase the stress response in this setting may be necessary to improve the external validity of this experimental framework.

The Effects of Novel Ingestion of Sodium Bicarbonate on Repeated Sprint Ability.

Abstract Miller, P, Robinson, AL, Sparks, SA, Bridge, CA, Bentley, DJ, and McNaughton, LR. The effects of novel ingestion of sodium bicarbonate on repeated sprint ability. J Strength Cond Res 30(2): 561–568, 2016—This work examined the influence of an acute dose of sodium bicarbonate (NaHCO3) on buffering capacity and performance during a repeated sprint ability (RSA) protocol. Eleven (mean ± SD: age 24.6 ± 6.1 years; mass 74.9 ± 5.7 kg; height 177.2 ± 6.7 cm) participated in the study, undertaking 4 test sessions. On the first visit to the laboratory, each participant ingested 300 mg·kg−1 of NaHCO3 (in 450 ml of flavored water) and blood samples were obtained at regular intervals to determine the individual times peak pH and HCO3−. In subsequent visits, participants ingested 300 mg·kg−1 of NaHCO3, 270 mg·kg−1 body mass (BM) of NaCI, or no drink followed by a RSA cycling protocol (10 × 6 seconds sprints with 60 seconds recovery), which commenced at each individuals predetermined ingestion peak pH response time. Blood samples were obtained before exercise and after the first, fifth, and 10th sprint to determine the blood pH, HCO3−, and lactate (La−) responses. Total work completed during the repeated sprint protocol was higher (p ⩽ 0.05) in the NaHCO3 condition (69.8 ± 11.7 kJ) compared with both the control (59.6 ± 12.2 kJ) and placebo (63.0 ± 8.3 kJ) conditions. Peak power output was similar (p > 0.05) between the 3 conditions. Relative to the control and placebo conditions, NaHCO3 ingestion induced higher (p ⩽ 0.05) blood pH and HCO3− concentrations before exercise and during the bouts, and higher lactate concentrations (p ⩽ 0.05) after the final sprint. Results suggest that NaHCO3− improves the total amount of work completed during RSA through enhanced buffering capacity.

Distance-dependent association of affect with pacing strategy in cycling time trials.

UNLABELLED The psychological construct of affect is proposed to significantly contribute to pacing decisions during exercise. Borgs RPE scale, another important regulator of work rate, is criticized as an inadequate measure of the multiple perceptual responses experienced. This study aimed to examine power output distribution and associated changes in affect, self-efficacy, perceptual cues, HR, and respiratory gases during both 16.1- and 40-km self-paced cycling time trials (TT). Secondly, the differentiation between physical perceptions of exertion and sense of effort in self-paced exercise was investigated. METHOD Fifteen trained male cyclists completed 16.1- and 40-km TT using a CompuTrainer cycle ergometer. Time, power output distribution, affect, self-efficacy, physical RPE (P-RPE), task effort and awareness (TEA), HR, and respiratory gases were measured throughout each TT. Linear mixed models explored associations of these variables with power output distribution and the relationship between P-RPE and TEA. RESULTS Similar pacing strategies were adopted in the 16.1- and 40-km TT (P = 0.31), and the main effects were found for affect (P = 0.001) and RER (P < 0.001). Interactions between affect (P = 0.037) and RER (P = 0.004), with condition, indicated closer associations with power output distribution in 16.1 km than that in 40 km TT. P-RPE was not significantly different from TEA (P = 0.053). CONCLUSION A significant association between affect and power output distribution suggests that affective responses are task dependent even in self-paced exercise, and a greater association is demonstrated in higher intensity, 16.1 km TT. Furthermore, physical perceptions of exertion are not clearly differentiated from the sense of effort in self-paced exercise.

Validity and Reliability of the Look Keo Power Pedal System for Measuring Power Output During Incremental and Repeated Sprint Cycling

UNLABELLED Power meters have traditionally been integrated into the crank set, but several manufacturers have designed new systems located elsewhere on the bike, such as inside the pedals. PURPOSE This study aimed to determine the validity and reliability of the Keo power pedals during several laboratory cycling tasks. METHODS Ten active male participants (mean ± SD age 34.0 ± 10.6 y, height 1.77 ± 0.04 m, body mass 76.5 ± 10.7 kg) familiar with laboratory cycling protocols completed this study. Each participant was required to complete 2 laboratory cycling trials on an SRM ergometer (SRM, Germany) that was also fitted with the Keo power pedals (Look, France). The trials consisted of an incremental test to exhaustion followed by 10 min rest and then three 10-s sprint tests separated by 3 min of cycling at 100 W. RESULTS Over power ranges of 75 to 1147 W, the Keo power-pedal system produced typical error values of 0.40, 0.21, and 0.21 for the incremental, sprint, and combined trials, respectively, compared with the SRM. Mean differences of 21.0 and 18.6 W were observed between trials 1 and 2 with the Keo system in the incremental and combined protocols, respectively. In contrast, the SRM produced differences of 1.3 and 0.6 W for the same protocols. CONCLUSIONS The power data from the Keo power pedals should be treated with some caution given the presence of mean differences between them and the SRM. Furthermore, this is exacerbated by poorer reliability than that of the SRM power meter.

Deception has no acute or residual effect on cycling time trial performance but negatively effects perceptual responses

OBJECTIVES Feedback deception is used to explore the importance of expectations on pacing strategy and performance in self-paced exercise. The deception of feedback from a previous performance explores the importance of experience knowledge on exercise behaviour. This study aimed to explore the acute and residual effects of the deception of previous performance speed on perceptual responses and performance in cycling time trials. DESIGN A parallel-group design. METHODS Twenty cyclists were assigned to a control or deception group and performed 16.1km time trials. Following a ride-alone baseline time trial (FBL), participants performed against a virtual avatar representing their FBL performance (PACER), then completed a subsequent ride-alone time trial (SUB). The avatar in the deception group, however, was unknowingly set 2% faster than their FBL. RESULTS Both groups performed faster in PACER than FBL and SUB (p<0.05), but SUB was not significantly different to FBL. Affect was more negative and Ratings of Perceived Exertion (RPE) were higher in PACER than FBL in the deception group (p<0.05). CONCLUSIONS The presence of a visual pacer acutely facilitated time trial performance, but deceptive feedback had no additional effect on performance. The deception group, however, experienced more negative affect and higher RPE in PACER, whereas these responses were absent in the control group. The performance improvement was not sustained in SUB, suggesting no residual performance effects occurred.

Sodium bicarbonate ingestion and individual variability in time-to-peak pH

ABSTRACT This study determined variability in time-to-peak pH after consumption of 300 mg kg−1 of sodium bicarbonate. Seventeen participants (mean ± SD: age 21.38 ± 1.5 years; mass 75.8 ± 5.8 kg; height 176.8 ± 7.6 cm) reported to the laboratory where a resting capillary sample was taken. Then, 300 mg kg−1 of NaHCO3 in 450 ml of flavoured water was ingested. Participants rested for 90 min and repeated blood samples were procured at 10 min intervals for 60 min and then every 5 min until 90 min. Blood pH concentrations were measured. Results suggested that time-to-peak pH (64.41 ± 18.78 min) was variable with a range of 10–85 min and a coefficient of variation of 29.16%. A bimodal distribution occurred, at 65 and 75 min. In conclusion, athletes, when using NaHCO3 as an ergogenic aid, should determine their time-to-peak pH to best utilize the added buffering capacity this substance allows.

Information Acquisition Differences between Experienced and Novice Time Trial Cyclists

Purpose To use eye-tracking technology to directly compare information acquisition behavior of experienced and novice cyclists during a self-paced, 10-mile (16.1 km) time trial (TT). Method Two groups of novice (n = 10) and experienced cyclists (n = 10) performed a 10-mile self-paced TT on two separate occasions during which a number of feedback variables (speed, distance, power output, cadence, HR, and time) were projected within their view. A large RPE scale was also presented next to the projected information and participants. Participants were fitted with a head-mounted eye tracker and HR monitor. Results Experienced cyclists performed both TT quicker than novices (F1,18 = 6.8, P = 0.018) during which they primarily looked at speed (9 of 10 participants), whereas novices primarily looked at distance (6 of 10 participants). Experienced cyclists looked at primary information for longer than novices across the whole TT (24.5% ± 4.2% vs 34.2% ± 6.1%; t18 = 4.2; P < 0.001) and less frequently than novices during the last quarter of the TT (49 ± 19 vs 80 ± 32; t18 = −2.6; P = 0.009). The most common combination of primary and secondary information looked at by experienced cyclists was speed and distance, respectively. Looking at 10 different primary–secondary feedback permutations, the novices were less consistent than the experienced cyclists in their information acquisition behavior. Conclusions This study challenges the importance placed on knowledge of the endpoint to pacing in previous models, especially for experienced cyclists for whom distance feedback was looked at secondary to, but in conjunction with, information about speed. Novice cyclists have a greater dependence on distance feedback, which they look at for shorter and more frequent periods than the experienced cyclists. Experienced cyclists are more selective and consistent in attention to feedback during TT cycling.