In high-performance sport, science and medicine practitioners employ a variety of physical and psychological tests, training and match monitoring, and injury-screening tools for a variety of reasons, mainly to predict performance, identify talented individuals, and flag when an injury will occur. The ability to “predict” outcomes such as performance, talent, or injury is arguably sport science and medicine’s modern-day equivalent of the “Quest for the Holy Grail.” The purpose of this invited commentary is to highlight the common misinterpretation of studies investigating association to those actually analyzing prediction and to provide practitioners with simple recommendations to quickly distinguish between methods pertaining to association and those of prediction.
Alan McCall, Maurizio Fanchini and Aaron J. Coutts
Miranda J. Menaspà, Paolo Menaspà, Sally A. Clark and Maurizio Fanchini
Purpose : To validate the quantification of training load (session rating of perceived exertion [s-RPE]) in an Australian Olympic squad (women’s water polo), assessed with the use of a modified RPE scale collected via a newly developed online system (athlete management system). Methods: Sixteen elite women water polo players (age = 26  y, height = 1.78 [0.05] m, and body mass = 75.5 [7.1] kg) participated in the study. Thirty training sessions were monitored for a total of 303 individual sessions. Heart rate was recorded during training sessions using continuous heart-rate telemetry. Participants were asked to rate the intensity of the training sessions on the athlete management system RPE scale, using an online application within 30 min of completion of the sessions. Individual relationships between s-RPE and both Banister training impulse (TRIMP) and Edwards’ method were analyzed. Results : Individual correlations with s-RPE ranged between r = .51 and .79 (Banister TRIMP) and r = .54 and .83 (Edwards’ method). The percentages of moderate and large correlation were 81% and 19% between s-RPE method and Banister TRIMP, and 56% and 44% between s-RPE and Edwards’ method. Conclusions : The online athlete management system for assessing s-RPE was shown to be a valid indicator of internal training load and can be used in elite sport.
Maurizio Fanchini, Roberto Ghielmetti, Aaron J. Coutts, Federico Schena and Franco M. Impellizzeri
To examine the effect of different exercise-intensity distributions within a training session on the session rating of perceived exertion (RPE) and to examine the timing of measure on the rating.
Nineteen junior players (age 16 ± 1 y, height 173 ± 5 cm, body mass 64 ± 6 kg) from a Swiss soccer team were involved in the study. Percentage of heart rate maximum (%HR) and RPE (Borg CR100®) were collected in 4 standardized training sessions (conditions). The Total Quality of Recovery scale (TQR) and a visual analogue scale (VAS) for pain of the lower limbs were used to control for the effect of pretraining fatigue. Every session consisted of three 20-min blocks of different intensities (ie, low-moderate-high) performed in a random order. RPE was collected after every block (RPE5), immediately after the session (RPE-end), and 30 min after the session (RPE30).
RPE5s of each block were different depending on the distribution sequence (P < .0001). RPE-end, TQR, and VAS values were not different between conditions (P = .57, P = .55, and P = .96, respectively). The %HR was significantly different between conditions (P = .008), with condition 3 higher than condition 2 (74.1 vs 70.2%, P = .02). Edwards training loads were not significantly different between conditions (P = .09). RPE30 was not different from RPE-end (P > .05).
The current results show that coaches can design training sessions without concern about the influence of the within-session distribution of exercise intensity on session-RPE and that RPE can be collected at the end of the session or 30 min later.
Maurizio Fanchini, Ivan Ferraresi, Roberto Modena, Federico Schena, Aaron J. Coutts and Franco M. Impellizzeri
To examine the construct validity of the session rating perceived exertion (s-RPE) assessed with the Borg CR100 scale to measure training loads in elite soccer and to examine if the CR100 is interchangeable and can provide more-accurate ratings than the CR10 scale.
Two studies were conducted. The validity of the CR100 was determined in 19 elite soccer players (age 28 ± 6 y, height 180 ± 7 cm, body mass 77 ± 6 kg) during training sessions through correlations with the Edwards heart-rate method (study 1). The interchangeability with CR10 was assessed in 78 soccer players (age 19.3 ± 4.1 y, height 178 ± 5.9 cm, body mass 71.4 ± 6.1 kg) through the Bland–Altman method and correlations between change scores in different sessions. To examine whether the CR100 is more finely graded than the CR10, the proportions of responses corresponding to the verbal expressions were calculated (study 2).
Individual correlations between the Edwards method and s-RPE were large to very large (.52–.85). The mean difference between the 2 scales was –0.3 ± 0.33 AU (90% CI –0.41 to –0.29) with 95% limits of agreements (0.31 to –0.96 AU). Correlations between scales and between-changes scores were nearly perfect (.95 and .91–.98). Ratings corresponding to the verbal anchors were 49% in CR10 and 26% in CR100.
The CR100 is valid for assessing the training load in elite soccer players. It can be used interchangeably with the CR10 and may provide more-precise measures of exercise intensity.
Sharna A. Naidu, Maurizio Fanchini, Adam Cox, Joshua Smeaton, Will G. Hopkins and Fabio R. Serpiello
Purpose: To assess the convergent validity of the Borg CR100® scale to track internal training load (TL) in youth football players. Methods: A total of 19 youth football players (age = 15  y, height = 175.9 [12.3] cm, and body mass = 69 [15.4] kg) were monitored for 27 sessions, including training and games. Internal TL was assessed via session rating of perceived exertion (sRPE) and 2 heart-rate-based methods (Banister training impulse and Edwards TL). The correlations between sRPE and heart-rate-based TL, the differences in individual player intercepts and slopes, and the differences between types of sessions (training vs games) were assessed using a general linear mixed model with magnitude-based inferences. Results: Correlations between sRPE and Banister training impulse were very large at overall group level (r = .77; 90% confidence limits, .72–.80) and individual level (range .70–.95). Correlations between sRPE and Edwards TL were very large at overall group level (r = .84; 90% confidence limit, .82–.86) and large to very large at individual level (range .64–.93). A very likely small difference was found in the comparison between games and training sessions for the relationship between sRPE and Banister training impulse. Conclusions: The Borg CR100 scale is a valid method for monitoring TL in youth football players.
Javier Raya-González, Fabio Yuzo Nakamura, Daniel Castillo, Javier Yanci and Maurizio Fanchini
Purpose: To examine the association and predictive ability of internal load markers with regard to noncontact injuries in young elite soccer players. Methods: Twenty-two soccer players (18.6 [0.6] y) who competed in the Spanish U19 League participated in the study. During a full season, noncontact injuries were recorded and, using session rating of perceived exertion, internal weekly load (sum of load of all training sessions and matches for each week) and acute:chronic workload ratio (typically, acute = current week and chronic = rolling 4-wk average) were calculated. A generalized estimating equation analysis was used to examine the association of weekly and acute:chronic load-ratio markers with a noncontact injury in the subsequent week. Load variables were also analyzed for predictive ability with receiver operating characteristic curve and area under the curve. Results: No association was found for weekly load (odds ratio = 1.00; 90% confidence interval, 0.99–1.00) and acute:chronic load ratio (odds ratio = 0.16; 90% confidence interval, 0.01–1.84) with respect to injury occurrence. In addition, the analyzed load markers showed poor ability to predict injury occurrence (area under the curve < .50). Conclusions: The results of this study suggest that internal load markers are not associated with noncontact injuries in young soccer players and present poor predictive capacity with regard to the latter.