Data Analysis of Psychological Approaches to Soccer Research: Using LDA Topic Modeling

This study identifies the topical areas of research that have attempted a psychological approach to soccer research over the last 33 years (1990-2022) and explored the growth and stagnation of the topic as well as research contributions to soccer development. Data were obtained from 1863 papers from the Web of Science database. The data were collected through keyword text mining and data preprocessing to determine the keywords needed for analysis. Based on the keywords, latent Dirichlet allocation-based topic modeling analysis was performed to analyze the topic distribution of papers and explore research trends by topic area. The topic modeling process included four topic area and fifty topics. The "Coaching Essentials in Football" topic area had the highest frequency, but it was not statistically identified as a trend. However, coaching, including training, is expected to continue to be an important research topic, as it is a key requirement for success in the highly competitive elite football world. Interest in the research field of "Psychological Skills for Performance Development" has waned in recent years. This may be due to the predominance of other subject areas rather than a lack of interest. Various high-tech interventions and problem-solving attempts are being made in this field, providing opportunities for qualitative and quantitative expansion. "Motivation, cognition, and emotion" is a largely underrated subject area in soccer psychology. This could be because survey-based psychological evaluation attempts have decreased as the importance of rapid field application has been emphasized in recent soccer-related studies. However, measuring psychological factors contributes to the study of football psychology through a new methodology and theoretical background. Recognizing the important role of psychological factors in player performance and mental management, as well as presenting new research directions and approaches that can be directly applied to the field, will advance soccer psychology research.

How Accurate Are Coaches in Predicting Perceived Exertion of Their Athletes?

ABSTRACT

Ryan, GA, Bunn, JA, and Eisenman, ML. How accurate are coaches in predicting perceived exertion of their athletes? J Strength Cond Res 37(3): 684-687, 2023-Ratings of perceived exertion (RPE) are used extensively to subjectively evaluate workload in sport. The purpose of this study was to compare season long player to coach perceptions of RPE loads (RPEL) in Division I men's soccer and women's lacrosse programs. Coach and player self-reported RPE were collected during the competitive seasons for both teams within 30 minutes of training sessions. Scores of RPE were multiplied by recorded training time to determine RPEL and averaged to create a daily coach and player RPEL. Accuracy of RPEL prediction between coaches and players was determined via mean bias, mean absolute percent error (MAPE), correlation, and an equivalence test. Soccer coaches underestimated RPEL (1,345 ± 410 arbitrary unit [AU]) compared with players (1,372 ± 435 AU). The coach mean bias was -27.3 ± 151.9 AU, wieth an MAPE of 7.4%, a strong correlation (r = 0.937, p < 0.001), and coach to player equivalence (p = 0.045). Lacrosse coaches overestimated RPELs (876 ± 349 AU) compared with players (829 ± 214 AU). The coach mean bias was 47 ± 189 AU, with an MAPE of 14.7%, a strong correlation (r = 0.883, p < 0.001), and coach to player equivalence (p = 0.010). Analyses indicated that coaches accurately predicted player RPEL within both sports. Variance occurred on days with high RPELs, with overestimations occurring in lacrosse and underestimation in soccer. Coaches can use RPELs to assess subjective training load but should consider objective measures, including microtechnology, to provide a comprehensive assessment.

Internal Training Load Perceived by Athletes and Planned by Coaches: A Systematic Review and Meta-Analysis

Background

Rating of perceived exertion (RPE) and session RPE (sRPE) has been widely used to verify the internal load in athletes. Understanding the agreement between the training load prescribed by coaches and that perceived by athletes is a topic of great interest in sport science.

Objective

This systematic review and meta-analysis aimed to investigate differences between the training/competition load perceived by athletes and prescribed/intended/observed by coaches.

Methods

A literature search (September 2020 and updated in November 2021) was conducted using PubMed, Web of Science, Embase, and SPORTDiscus databases. The protocol was registered in the Open Science Framework (osf.io/wna4x). Studies should include athletes and coaches of any sex, age, or level of experience. The studies should present outcomes related to the RPE or sRPE for any scale considering overall training/competition sessions (physical, strength, tactical, technical, games) and/or classified into three effort categories: easy, moderate, and hard.

Results

Twenty-seven studies were included in the meta-analysis. No difference was found between coaches and athletes for overall RPE (SMD = 0.19, P = 0.10) and overall sRPE (SMD = 0.05, P = 0.75). There was a difference for easy RPE (SMD = − 0.44, small effect size, P = 0.04) and easy sRPE (SMD = − 0.54, moderate effect size, P = 0.04). No differences were found for moderate RPE (SMD = 0.05, P = 0.74) and hard RPE (SMD = 0.41, P = 0.18). No difference was found for moderate (SMD = -0.15, P = 0.56) and hard (SMD = 0.20, P = 0.43) sRPE.

Conclusion

There is an agreement between coaches and athletes about overall RPE and sRPE, and RPE and sRPE into two effort categories (moderate and hard). However, there were disagreements in RPE and sRPE for easy effort category. Thus, despite a small disagreement, the use of these tools seems to be adequate for training monitoring.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40798-022-00420-3.

Differences in execution and perception of training sessions as experienced by (semi-) professional cyclists and their coach

This study aimed to investigate whether (semi-)professional cyclists' execution of a training programme differs from the coach's designed training programme. Also, the study sought to ascertain, in instances where the training sessions were indeed executed as designed by the coach, whether the perception of the cyclists differed from the intention of the coach. This study highlights the differences between the coach and the individual cyclist. In total, 747 training sessions were collected from 11 (semi-)professional cyclists. Rating of Perceived Exertion (RPE) and session Rating of Perceived Exertion (sRPE) were compared with intended RPE (iRPE) and intended sRPE (isRPE), planned by the coach. Pearson's correlation, regression coefficients and Typical Error of Estimate (TEE) were used to identify differences between the executed and planned training sessions. Moderate to large TEEs were noted between executed and intended sRPE, which indicates that cyclists do not always execute the training programme planned by the coach. Furthermore, when the training was executed as planned by the coach, very large correlations but moderate to very large TEEs were noted between cyclists' (s)RPE and the coach's i(s)RPE, with unique individual regression coefficients. This indicates that the relationship between RPE and iRPE is unique to each cyclist. Both the different execution and perception of the training programme by the individual cyclists could cause an impaired training adaptation. Therefore, the coach must pay attention to the perception of training sessions by the individual cyclist. Improved individual management of training load could result in the optimisation of the proposed training programme.Highlights On individual level, (semi-)professional cyclists train differently than planned by the coach, based on duration and sRPE of the training sessionsThe relationship between the RPE of the cyclist and the iRPE of the coach is unique for each cyclistCoaches should be aware that cyclist and coach could interpret the same training differently, resulting in an easier perception of low- and high- intensity training sessions by the cyclists compared to the intention of the coach.

Comparison of coach-athlete perceptions on internal and external training loads in trained cyclists

ABSTRACTThe aim was to compare the rating of perceived exertion (RPE), duration and session-RPE (S-RPE) prescribed by the coaches to those perceived by the cyclists in training sessions. The classification of RPE, duration and S-RPE of 14 male road cycling and mountain biking athletes were compared with the planned values of five coaches. The results revealed no differences for average RPE (P = 0.586), duration (P = 0.717) and S-RPE (P = 0.738) between coaches and cyclists. When comparing the three categories of effort, the results of the intensity of training sessions designed to be easy were perceived as significantly harder by cyclists compared to coaches (3.0 [2.0] vs. 2.0 [0.0] a.u.; P = 0.013). In addition, the correlations between coaches and cyclists on RPE (r = 0.73), duration (r = 0.95) and S-RPE (r = 0.87) were large, almost perfect and very large (P < 0.0001) respectively. In conclusion, our results indicate a mismatch between coaches (prescription) and cyclists (perception) of easy RPE training sessions, where the cyclists perceived the session harder. However, the S-RPE can be used to prescribe and quantifying the internal training load of trained cyclists.

Factors Influencing the Association Between Coach and Athlete Rating of Exertion: a Systematic Review and Meta-analysis

BACKGROUND

Subjective monitoring of rate of perceived exertion is common practice in many sports. Typically, the information is used to understand the training load and at times modify forthcoming sessions. Identifying the relationship between the athlete and coach's interpretation of training would likely further benefit understanding load management. The aim of this systematic review was to evaluate the relationship between coaches' rating of intended exertion (RIE) and/or rating of observed exertion (ROE) and athletes' reported rating of perceived exertion (RPE).

METHODS

The review was undertaken in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We conducted a search of Medline, Google Scholar, Science Direct, SPORTDiscus, and Web of Science databases. We assessed the correlation between coach-reported RIE and/or ROE and RPE. Assessment for risk of bias was undertaken using the Quality Appraisal for Reliability Studies (QAREL) checklist. Inclusion criteria were (1) male and/or female individuals, (2) individual and/or team sport active participants, and (3) original research article published in the English language.

RESULTS

Data from 19 articles were found to meet the eligibility criteria. A random effect meta-analysis based on 11 studies demonstrated a positive association of player vs. coach rating of RIE (r = 0.62 [95% CI 0.5 to 0.7], p < 0.001). The pooled correlation from 7 studies of player vs. coach rating on ROE was r = 0.64 95% CI (0.5 to 0.7), p < 0.001.

CONCLUSION

There was a moderate to high association between coach RIE and/or ROE and athlete-reported RPE and this association seems to be influenced by many factors. The suggestions we present in this review are based on imploring practitioners to consider a multi-modal approach and the implications of monitoring when using RPE.

TRIAL REGISTRATION

CRD42020193387.

Internal training load monitoring in professional football: a systematic review of methods using rating of perceived exertion

INTRODUCTION

The rate of perceived exertion (RPE) is widely adopted to quantify internal training load (ITL) in professional football. The aim of this study was to systematically review the use RPE-based methods in professional football.

EVIDENCE ACQUISITION

Observational studies conducted during training routines of professional football players over a minimum of one-week were selected based on the preferred reporting items for systematic reviews and meta-analyses statement.

EVIDENCE SYNTHESIS

Thirty-eight articles met the inclusion criteria (average qualitative score was 6.3 out of 10 [3 to 9]). The main deficiencies identified concerned the poor description of study design (~52% of the studies), and the non-quantification of match load (~44%). Ten studies complemented RPE-based ITL information with time-motion analysis (~26%) and seven studies added HR recordings (~18%). Nine studies collected RPE data after complementary training, separately to field sessions (~3%). Operational questions (e.g. How was your workout? ~71%) were preferred to instructions (e.g. Please rate the intensity of today's session; ~8%). Session-RPE (s-RPE; RPE multiplied by training duration) was more commonly adopted as measure of exercise intensity than isolated RPE (~76 vs. ~8%). RPE-derived variables calculated on weekly values included absolute week-to-week change, acute: chronic workload ratio, monotony and strain and were not frequently used (7 to 15%). Four studies (~11%) divided RPE in two components: respiratory and muscular.

CONCLUSIONS

There is a lack of consensus for the use of RPE in professional football and "good practices" are warranted. This review might help practitioners regarding procedures to adopt in RPE data collection and interpretation.

Relationship of Pre-season Training Load With In-Season Biochemical Markers, Injuries and Performance in Professional Soccer Players

INTRODUCTION

There is controversy in the literature in regards of the link between training load and injury rate. Thus, the aims of this non-interventional study were to evaluate relationships between pre-season training load with biochemical markers, injury incidence and performance during the first month of the competitive period in professional soccer players.

MATERIALS AND METHODS

Healthy professional soccer players were enrolled in this study over two pre-season periods. Data sets were available from 26 players during the first season (2014-2015) and 24 players during the second season (2015-2016) who completed two pre-season periods (6 weeks each). External training load was assessed from all athletes during training using Global Positioning System (GPS). Internal training load was monitored after each training session using rate of perceived exertion (RPE). Before and after each pre-season, blood samples were taken to determine plasma lactate dehydrogenase (LDH), creatine kinase (CK) and C-reactive protein (CRP). Injury incidence and overall performance (ranking of the team after the first five official games of the championship) were recorded for both seasons separately.

RESULTS

There was no statistically significant difference in mean RPE values of the two-preparation periods (2737 ± 452 and 2629 ± 786 AU, p = 0.492). The correlational analysis did not reveal significant associations between internal and external training load (RPE and GPS data) and biological markers. There was a significant positive correlation between RPE and LDH during the 2015/2016 season (r = 0.974, p = 0.001). In addition, a significant negative correlation was found between total distance >20 km/h and CRP during the 2015-2016 season (r = -0.863, p = 0.027). The injury rates for the two seasons were 1.76 and 1.06 per 1000 h exposure for the 2014-2015 and 2015-2016 seasons, respectively (p = 0.127).

CONCLUSION

Our study showed that pre-season training load is not associated with overall team performance. This association is most likely multifactorial and other factors (e.g., technical and tactical level of the team, opponents, environment) may play an important role for the collective team performance. Our findings may help coaches to better prepare their athletes during pre-season.

Comparisons of Perceived Training Doses in Champion Collegiate-Level Male and Female Cross-country Runners and Coaches over the Course of a Competitive Season

Background

Session rating of perceived exertion (sRPE) is a practical tool for coaches to assess internal training load of their athletes. In a sport like cross-country running, that is individual in nature, but has a team training and competition component, information about the association between external and internal load is lacking. Furthermore, there is a need for studies that examine perception of training doses across multiple training cycles including the competitive season as well as between male and female athletes.

Methods

Session RPE, duration, and training load (TL_RPE = sRPE × duration) of 25 highly trained male and female cross-country runners and their coaches were recorded for every training session (110 days) throughout a collegiate cross-country season. Intensity (sRPE), duration, and TL_RPE were compared between coaches and runners by gender separately. Training sessions were also analyzed by those intended by the coaches to be easy, moderate, and hard as well as by training period.

Results

Data from 3024 training sessions were collected, 62% of which were considered “easy,” 18% “moderate,” and 20% “hard.” Men and women rated coach-intended easy sessions significantly harder during each month of the season (effect size (ES) > 2.9, p < 0.0001). Men rated moderate intensity sessions significantly higher than coaches (ES ≥ 1.0, p ≤ 0.002), whereas females rated hard intensity sessions significantly lower than coaches (ES > 0.5, p < 0.008). There was no difference between males and coach’s hard sessions (ES < 0.07, p > 0.05) or females and coach’s moderate sessions (ES < 0.18, p > 0.05). Training intensity and TL_RPE tended to increase throughout the season (p > 0.05), with a significant increase in moderate and hard intensity sessions in the last training period (p < 0.001).

Conclusions

The results indicate the male and female cross-country runners tend to regress to moderate intensity training throughout the cross-country season. Given the success of the athletes in this study, these results show how a simple system for monitoring training such as the sRPE method may improve control of training variables and provide a useful tool for coaches to evaluate training load placed on athletes in a simple, responsive way.