Personal pdf file for J. Fernandez-Fernandez, D. A. Boullosa, D. Sanz-Rivas, L. Abreu, E. Filaire, A. Mendez-Villanueva
www.thieme.de
With compliments of Georg Thieme Verlag
Psychophysiological Stress Responses during Training and Competition in Young Female Competitive Tennis Players DOI 10.1055/s-0034-1384544 Int J Sports Med For personal use only. No commercial use, no depositing in repositories.
Publisher and Copyright © 2014 by Georg Thieme Verlag KG Rüdigerstraße 14 70469 Stuttgart ISSN 0172-4622 Reprint with the permission by the publisher only
Training & Testing
Psychophysiological Stress Responses during Training and Competition in Young Female Competitive Tennis Players
Authors
J. Fernandez-Fernandez1, D. A. Boullosa2, D. Sanz-Rivas3, L. Abreu4, E. Filaire5, A. Mendez-Villanueva6
Affiliations
Affiliation addresses are listed at the end of the article
Key words ▶ psychophysiology ● ▶ young athletes ● ▶ tennis ● ▶ stress ● ▶ performance ● ▶ sport physiology ●
Abstract
▼
This study sought to compare the psychophysiological stress responses during an actual competitive game and a training session in a group of high-level young female tennis players. 12 players were monitored during one match and a training day (i. e., simulated match play). Measurements included salivary cortisol (SC), the revised Competitive Sport Anxiety Inventory, heart rate (HR), and rate of perceived exertion (RPE). Match day elicited higher SC levels for losers at all points in time when compared to winners. All players showed significantly lower SC levels during training when compared to the match at all points in time except dur-
Introduction
▼
accepted after revision May 23, 2014 Bibliography DOI http://dx.doi.org/ 10.1055/s-0034-1384544 Published online: 2014 Int J Sports Med © Georg Thieme Verlag KG Stuttgart · New York ISSN 0172-4622 Correspondence Dr. Jaime Fernandez- Fernandez Sports Research Centre Miguel Hernandez University Avenida de la Universidad s/n 03202 – Elche, (Alicante) Spain Tel.: + 34 965222523
[email protected]
Tennis involves intermittent, high-intensity efforts interspersed with periods of low-intensity activity during which active and passive recovery periods occur [18], thus inducing important physical and psychological stress [19, 55]. Psychological stress might play an important role during tennis competition as it requires steadiness, precision, motivation and motor control for effective shot-making over the whole match [8, 45]. Previous studies on stress responses to competition have suggested the important psychophysiological demands of actual play as reflected on psychological (e. g., rate of perceived exertion (RPE); anxiety) and physiological (e. g., heart rate (HR), cortisol) responses [20, 33, 39, 44]. However, the interaction between these different stress components is still unknown in tennis. For instance, Filaire et al. [20] previously reported greater somatic anxiety and lower self-confidence in females with respect to males, with a similar pattern of cortisol responses during the first game of a tennis
ing the evening for winners. Winners of match and training situations had significantly higher self-confidence and lower cognitive anxiety and somatic anxiety scores than losers. Heart rate and RPE were significantly higher for losers only during the match (158.9 ± 8.3 vs. 168 ± 6.7 bpm; 12.9 ± 1.2 vs. 15 ± 0.8, for losers and winners, respectively). There were moderate to strong correlations between SC, self-confidence and anxiety scores, and match workload (i. e., HR and RPE) only during the match day. These results indicate that the interplay between psychophysiological responses, match workload and outcome was evident only under real competitive situations.
tournament. The article, however, provided no information on the physiological demands of the games. Young tennis players usually compete in 15–25 tournaments per year, which equates to 50–120 competitive single matches [7]. Knowledge about psychophysiological demands of competition is essential for improving the effectiveness of the training process [48], especially in the area of youth sports [5]. However, the effect of psychophysiological stress induced by a tennis event is still not well understood, especially when it comes to young athletes. Moreover, tennis players devote a great amount of time to improving their tennis skills through technical and tactical training, with an average of 15–20 h of technical training per week even at a young age [7]. Previous research has shown that psychophysiological challenges associated with training and competition settings can induce different responses, especially in the case of hormonal parameters, with these physiological responses being intensified during competitions [13, 28, 41] and altered during subsequent recovery days [13]. Further-
Fernandez-Fernandez J et al. Psychophysiological Stress Responses during … Int J Sports Med
Training & Testing more, the International Olympic Committee recently recommended international federations to monitor the demands of both training and competition, given that young athletes could be exposed to excessive psychophysiological stress [43]. It is therefore important to understand the role of these responses in both settings, as they will provide valuable information (i. e., training loads), enabling training to be optimized and preventing continuous exposure to stress among developmental athletes [42]. Cortisol has been shown to be a good indicator of stress [3, 20, 26]. This steroid hormone plays a central role in the physiological and behavioural response to stress, with the activation of the hypothalamic-pituitary-adrenocortical axis (HPA) stimulating its release from the adrenal cortex [37]. Salivary cortisol (SC), as a representative marker of circulating free cortisol [32, 56], has been recommended as an index of training stress in sport settings, as it avoids the stress caused by venepuncture, thus reducing artificially high values due to an anticipatory effect [26]. More specifically, SC has been used to determine psychophysiological stress responses to competition in different sports, with significant increases reported before and after competitive situations, reflecting both an anticipatory response and the result of the high-intensity actions [10, 11, 20, 23, 28, 38, 46]. An increase in this hormone appears to be important while preparing for mental and physical competitive demands, as a previous study reported that individuals with greater cortisol levels and motivation before competition exhibited a greater outcome [50]. However, extreme elevations in cortisol may lead to poor performance because it may interfere with some cognitive processes [14]. Thus, mild increases in cortisol may prepare individuals for action, whereas lower cortisol concentrations may indicate greater resilience to stressful situations [52]. Furthermore, it is still under debate whether the competitive outcome (i. e., winners vs. losers) could influence in SC responses [2, 53], with most of the previous research being conducted only among adults. The combination of SC and anxiety measures seems to provide a sensitive index of stress response as shown by the reported relationships between somatic and cognitive anxiety and cortisol [21, 38] or by the direction of anxiety components and cortisol [15]. The revised Competitive State Anxiety Inventory-2 (CSAI-2 R) is a simple and valid instrument for the assessment of self-confidence and anxiety before athletic competition [6]. Its use concurrently with the evaluation of other physiological parameters (e. g., HR or SC) has allowed a better characterisation of psychophysiological responses to competition in tennis as in other sports [1, 21]. In this regard, Filaire et al. [20] have shown that in adult female tennis players, winners of competitive matches exhibited significantly higher self-confidence and cognitive anxiety, and lower somatic anxiety scores compared to losers. However, the literature has also shown that good performances could be also related to high levels of anxiety and low levels of self-confidence [30, 47]. Additionally, the same level of competitive anxiety may be perceived by some athletes as facilitative and by others as debilitative [29]. This controversy raises some doubts about the interaction between the psychological and physiological stress components of competitive tennis players that warrants further research, especially among young athletes. Therefore, the aims of this study were to compare the psychophysiological stress responses during a real competitive game and a training competitive session with regard to outcomes, i. e.,
winners (the players who won both situations, real and simulated match-play) vs. losers (those who lost both situations); and to examine the relationship between physiological and psychological stress components and self-related anxiety scores in a group of high-level young female tennis players. It was hypothesized that psychological and physiological stress components would be heightened and more clearly linked during the competition day compared to the training day, and that these responses would be more evident in losers.
Methods
▼
Participants
12 young female elite tennis players (Age: 13.0 ± 0.3 years; weight: 51.4 ± 1.3 kg; height: 168 ± 3.3 cm; BMI: 18.1 ± 0.7) free of cardiorespiratory and musculoskeletal illnesses participated in this study. All of the players were regularly involved in Under-14 tennis competition on the national and international level (i. e., International Tennis Federation (ITF) and Tennis Europe tournaments) and were of similar competitive level (i. e., national ranking between 5 and 20) at the time of the study. The mean training experience of players was 6 ± 2.8 years, which included tennisspecific training (i. e., technical and tactical skills), aerobic and anaerobic training (i. e., on- and off-court exercises), and basic resistance training. The study was performed in accordance with the ethical standards of the IJSM [31], and conformed to the recommendations of the Declaration of Helsinki. The purpose of the study was explained to both the participants and their parents, all of them giving their informed consent. Approval for the project was obtained from the local institutional research ethics committee.
Procedures Salivary cortisol samples
To obtain reference values, 2 saliva samples were taken 2 weeks before a tennis tournament on a normal day following a 24 h training-free period (i. e., control day; C) at the beginning of the summer competitive season (i. e., April). These samples were taken individually by the players’ parents 30 min after awakening at 8:00 a.m. and during the evening at 8:00 p.m. These time intervals were selected to account for circadian influences on SC levels [35]. Participants were instructed to complete sampling before eating or drinking to prevent contamination of saliva. Participants were also told to thoroughly rinse their mouth with tap water before sampling and, furthermore, not to brush their teeth before completing saliva sampling to prevent contamination of saliva with blood caused by microinjuries in the oral cavity [20]. Participants provided 5–10 ml of saliva in a plastic tube with cotton (Salivette®, Sarstedt, France). Saliva samples were then stored frozen in the participants’ refrigerators. Within 2 days, samples were then collected and frozen in the laboratory’s refrigerator at − 30 °C until assay. Subsequently, 4 saliva samples were collected for comparisons between a match day (MD) and a training day (TD) according to the procedures described in Filaire et al. [20]: 30 min after awakening (8:00 a.m.); 10 min before the beginning of the match (3:00 p.m.); 10 min after the end of the match (5:30 p.m.); and in the evening (8:00 p.m.; before dinner). The TD was performed 2 weeks after the tournament for matching the same players as in MD and to ensure that the participants had fully recovered [42]. Salivary cortisol concentration was determined in duplicate
Fernandez-Fernandez J et al. Psychophysiological Stress Responses during … Int J Sports Med
Training & Testing
Table 1 Psycho-physiological responses of the players during the competitive and training situations. Data presented as mean ± SD. HR: heart rate; %HRmax: percentage of maximum heart rate; RPE: ratings of perceived exertion; M: match-play; T: training.
HR %HRmax RPE
Winners – M
Losers – M
Winners – T
Losers – T
158.9 ± 8.3 79.7 ± 4.3 12.9 ± 1.2
168 ± 6.7 # 84.8 ± 3.2*# 15 ± 0.8*#
160.3 ± 3.0 80.6 ± 3.1 11.9 ± 2.0
161.7 ± 6.3 81.5 ± 3.3 12 ± 1.8
*#
30
Statistical analyses
Cortisol (nmol ·L– 1)
25 20 15 10
*# 5 0
* Rest
Match
tennis match/practice. The number of measurements taken for each player was variable, depending on the duration of the match/training (i. e., 2 or 3 sets) and the number of games played in each set. HR was monitored using a HR monitor (Polar S610, Kempele, Finland) at a sampling rate of 5 s. The percentage of maximum HR ( %HRmax) was calculated from the HRmax recorded during matches. RPE was obtained using the 15-category Borg RPE scale [4]. All participants were familiarized with the use of this scale. While sitting, the participants were asked, “how hard do you feel the exercise was?”.
Training
Rest
8:00h
Match
*
Training
The variables are presented as mean (SD). The KolmogorovSmirnov test (with Lilliefor’s correction) was used to verify normal distribution of the data. Differences between parameters at different times (awakening, pre-competition, post-competition, evening), days (C, MD, TD) and match outcome (winner vs. loser) were examined using analysis of variance (ANOVA) for repeated measurements (time × day × outcome) and pairwise comparisons with Bonferroni correction. The relationships between variables were determined using Pearson’s product moment correlation analysis. SPSS V.17 was used for statistical calculations. The level of significance was set at p
