Practical tests for monitoring performance, fatigue and recovery in triathletes

Journal of Science and Medicine in Sport (2007) 10, 372 381 ORIGINAL PAPER Practical tests for monitoring performance, fatigue and recovery in triathletes Aaron J. Coutts, Katie M. Slattery, Lee K. Wallace School of Leisure, Sport and Tourism, University of Technology, Sydney, Australia Received 1 August 2006; received in revised form 1 February 2007; accepted 2 February 2007 KEYWORDS Overreaching; Athlete monitoring; DALDA; Jump tests Summary Few studies have described simple tests which can be used to provide an early warning of overreaching. The purpose of this study was to examine selected practical tests for monitoring changes in performance, fatigue and recovery of endurance athletes. Sixteen male triathletes were randomly assigned into matched groups. The normal training (NT) and intensified training (IT) groups completed 4 weeks of training followed by a 2-week taper. Physiological measures were taken pre- and post-overload and post-taper periods during an incremental treadmill test to exhaustion. Performance was assessed weekly using a 3-km run time trial (3 kmtt). Five-bound jump for distance (5BT) and submaximal running heart rate (HR submax ) test were measured twice weekly and the Daily Analyses of Life Demands for Athletes (DALDA) were recorded. During the overload training period, the IT group completed 290% more training load than the NT group (p < 0.001). After the overload training period, 3 kmtt in the IT group was reduced compared to both pre-training (3.7%, p < 0.05) and the NT group (6.8%, p < 0.05). 5BT was decreased by 7.9% in the IT group following the overload period (p < 0.05). The IT group also demonstrated increases in stress reaction symptoms from the DALDA. Following the taper, the IT group improved 3 kmtt. In contrast, the performance, physiological and psychological markers of NT group remained relatively unchanged throughout the 6-week training period. There were weak significant correlations between weekly changes in 3 kmtt and 5BT (r = 0.37, p < 0.01). The DALDA and 5BT may be practical tests for assessing changes in performance, fatigue and recovery of endurance athletes. 2007 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. Introduction It is well established that an appropriately designed training plan can improve athletic performance. 1 Corresponding author. E-mail address: aaron.coutts@uts.edu.au (A.J. Coutts). However, when increased intensive physical training is completed without sufficient recovery periods, fatigue may accumulate resulting in a reduced performance capacity. 2 These periods of intensified training can lead to either functional (short-term) overreaching, non-functional (extreme) overreaching or in severe cases, to the Overtraining Syndrome. 3 1440-2440/$ see front matter 2007 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jsams.2007.02.007

Monitoring training 373 Deliberate functional overreaching is common in many physical training programs and is considered by many coaches to be part of the normal training process for athletes. 3 Indeed, some studies have shown that functional overreaching may lead to enhanced performance when appropriate recovery or taper periods follow the intensified training. 4 However, if athletes continue to train intensively during functional overreaching, non-functional overreaching or even the Overtraining Syndrome can manifest. During non-functional overreaching, an athlete may present with a range of symptoms (e.g., hormonal dysregulation, psychological disturbances, reduced immune function, sleep disorders) and require weeks or months to restore performance capacity. 3 The symptoms for the more serious of these conditions, the Overtraining Syndrome, are the same as for non-functional overreaching with the delineation between these conditions being made on the basis of the length of time taken to recover. The challenge for coaches and athletes is to determine the point at which training becomes maladaptive. The result of intensified training is difficult to predict because each individual athlete s response to overreaching can be variable. 5 Therefore, accurate athlete monitoring during the training process may assist in the prevention of non-functional overreaching and the Overtraining Syndrome. Various theories have emerged which propose that overreached/overtrained athletes have a dysregulation of either the metabolic, hormonal, physiological and/or immunological systems. 5 9 However, there is still no consensus regarding simple tests which can be used to provide an early warning of impending non-functional overreaching or the Overtraining Syndrome. Currently, the only reliable method of diagnosis is through a decrease in performance. 2 Therefore, instead of investigating the cause of overreaching, this study will examine the usefulness of several practical tests to monitor changes in running performance for use as possible indicators of the performance decrements associated with overreaching. Methods Subjects Sixteen experienced male triathletes volunteered to participate in this study. The subjects physical characteristics are shown in Table 2. All participants had regularly competed in triathlon for at least 3 years, performing more than six triathlons per year and training a minimum of 8 h week 1. Ten subjects had competed at a national and international level for their respective age groups. Prior to the commencement of testing, subjects were informed of the purpose and the potential benefits/risks of the study. All subjects gave written consent prior to the commencement of the research. The study was approved by the university s Human Ethics Committee and was conducted in accordance with the Helsinki Declaration. Experimental protocol Subjects were randomly assigned to either the (1) experimental group (intensified training (IT) group) or the (2) control group (normal training (NT) group) according to a matched group experimental design based on maximal oxygen uptake ( VO 2max ) and 3-km run time trial (3 kmtt) performance. The IT group completed a 4-week overtraining program designed deliberately to overreach the subjects. The NT group completed 4 weeks of selfselected normal progressive overload training. Both groups performed a 2-week taper immediately following the 4-week training period in accordance with the tapering recommendations for endurance athletes. 10 The control group was included to allow for comparisons to be made between adapting and non-adapting athletes. The investigation was conducted during the base phase of physical training after 3 weeks of lowvolume, moderate-intensity training (maximum of 5 h week 1 ) following the previous competitive triathlon season. Prior to participation in the investigation, subjects underwent a comprehensive screening process including blood analysis, psychometric evaluation and medical assessment. 11 Throughout the 6-week experimental period, selected performance, physiological and psychological tests were completed by all subjects. The 3 kmtt was performed weekly and a submaximal running heart rate (HR submax ) test and five-bound test (5BT) were performed twice weekly during the 4-week training period. These performance tests were completed after a warm up but before the main training set on each of these days. No field-based tests (3 kmtt, 5BT or HR submax ) were conducted during the first week of the taper. During the second week of the taper the subjects completed the 3 kmtt once and the HR submax test and 5BT twice. Physiological testing was conducted prior to the 4-week training period, following the training period and at the completion of the 2-week taper. The Daily Analyses of Life Demands for Athletes (DALDA) 12 was com-

374 A.J. Coutts et al. pleted at the same time each day throughout the study. Physical training The physical training for the IT group consisted of a 4-week progressive overload period followed by a 2-week taper and has been described in detail previously. 11 During the overload period the NT group completed 4 weeks of self-selected physical training. In contrast, the IT group completed a 4- week physical training program with much greater training load in an attempt purposely to overreach the athletes. Training consisted of warm-up, stretching and either swimming, cycling and running. Training load was calculated by a product of session duration and session intensity using the methods of Foster et al. 13 A rating of perceived exertion (Category Ratio-10 RPE Scale 14 ) was used to measure the overall intensity of the session evaluated 30 min following each session. This method of quantifying training load has previously been shown to provide approximately the same information regarding the relative training intensity as the method of Banister 15 which relies on continuous measures of heart rate. Field-based performance tests All field-based tests were performed on an outdoor synthetic 400-m track at the same time of day (approximately 18.20). The ambient temperature ranged between 17 C and 19 C and between 40% and 55% relative humidity. The field-based performance tests were performed in the same order HR submax test, 5BT, then 3 kmtt following a standard warm up. Maximal 3 km run time trial The 3 kmtt was chosen as the primary performance test for this study as it has been suggested that maximal effort time-trials are ideal for evaluation of performance 16 and are suitable for assessing overreaching. 8 The subjects were instructed to run the 3 km in the fastest possible time. The subjects were not informed of their lap splits and given equal verbal encouragement. The repeat test reliability of the 3 kmtt was high (technical error of measure (TEM) = 9.2 s, TEM% = 1.4). Submaximal heart rate test The HR submax test was designed to measure the heart rate during a standardised shuttle running protocol warm up. Subjects ran back and forth over a 20-m course on the running track and touched the 20-m line with their foot at the same time that a sound signal was emitted from a compact disk. The shuttle run protocol consisted of three 2-min stages, each followed by a 1-min rest. At the end of each stage, peak heart rate was recorded (Polar Team System, Polar, OY, Finland). The running velocities were Stage 1: 9.6 km h 1 ; Stage 2: 10.8 km h 1 ; Stage 3: 12.0 km h 1. For this study, only heart rate data recorded immediately at the completion of Stage 3 were used for analysis (TEM = 2.7 bpm, TEM% = 1.6). Five-bound test To complete the 5BT the subjects were required to stand with their preferred foot forward at the beginning of a tape measure and bound five consecutive times with alternative left and right foot contacts in an attempt to cover the greatest horizontal distance. 17 The distance of the jump was measured from the beginning of the tape measure to the heel of the rear foot on the fifth jump. The subjects performed three trials and the jump in which the greatest horizontal distance was covered was recorded. The repeat test reliability of the 5BT for this group of athletes was observed to be good (TEM = 0.25 m, TEM% = 2.3). Laboratory physiological tests Laboratory tests were completed in a standard order and at the same time of day for each testing occasion. Firstly, anthropometrical measures were taken and then an incremental treadmill run to exhaustion. In the 24 h prior to testing, subjects were instructed to refrain from exercise and standardise their food and fluid intake. Maximal oxygen uptake Maximal oxygen uptake ( VO 2max ) was measured using a discontinuous incremental treadmill run to exhaustion. 18 The work protocol and criteria for attainment of VO 2max used in this study have been previously described. 11 The reliability of VO 2max measures for this laboratory were high (TEM = 1.5 ml kg 1 min 1, TEM% = 3.1). Running economy Running economy was taken as the steady-state VO 2 (ml kg 1 min 1 ) during the last minute of running at a velocity of 14.5 km h 1 during the incremental treadmill test. Lactate threshold Lactate threshold was calculated as the running velocity corresponding with a blood lactate concentration of 4 mmol L 1 during the incremental

Monitoring training 375 treadmill running test to exhaustion. At the immediate completion of each workload a blood lactate sample was taken (Accusport Portable Lactate Analyser, Boehringer, Germany). The repeat test reliability of lactate threshold was found to be moderate (TEM = 1.0 km h 1, TEM% = 2.7). Lactate to rating of perceived exertion ratio The lactate to RPE (La:RPE) ratio was obtained by dividing blood lactate concentration by RPE (Category Ratio-10 RPE Scale) and multiplying by 100. The La:RPE ratio was determined following the 4-min stages at 13.0 km h 1, 14.5 km h 1 and 16 km h 1. Maximal La:RPE was calculated at the immediate completion of the test. Anthropometric measures All anthropometrical measures (height, skinfolds, girths and body weight) were taken by a trained anthropometrist using standard methods. 19 Psychological measures Daily Analyses of Life Demands for Athletes Each subject was required to complete the DALDA questionnaire at the same time each day to assess general stress levels (Part A) and to determine stress-reaction symptoms (Part B) of the participants. 12 The questionnaire required the subject to rate each variable as being worse than normal, normal or better than normal. When the athlete reported an increased amount of worse than normal responses on three consecutive days, it was concluded that the athlete was in a state of stress. Statistical analyses The 3 kmtt data were analysed by a two-factor (condition, testing occasion) analysis of covariance (ANCOVA) with the pre-testing 3 kmtt time entered as a covariate to adjust statistically the post-test 3 kmtt performance to take into account the pretest differences. The results of the physiological and psychological tests were analysed by a twofactor (condition, testing occasion) multivariate repeated measures analysis of variance with both repeated and simple contrasts to determine the within group differences. An independent samples t-test with a Bonferroni adjustment was used to determine between group differences at each testing time. Pearson s product moment correlations coefficient (r) was used to examine the correlation between the weekly change in 3 kmtt ( 3 kmtt) and the weekly change in 5BT ( 5BT), HR submax test ( HR submax ) with weekly change in total training load ( TL), run training load ( RunTL), bicycle training load ( BicycleTL) and combined run and bicycle training load ( Run/BicycleTL). A statistical software package (SPSS Version 12.0, Chicago, USA) was used for all statistical calculations. Significance was set at p < 0.05. Results There were no differences between the IT and NT groups in age, height, VO 2max and 3 kmtt prior to the commencement of the training period. However, differences were found between groups for body mass (p = 0.019) and 9 skinfolds (p = 0.018). The training loads for the IT and NT groups during the 6-week training period are shown in Table 1 and have been previously reported in detail. 11 The IT group was observed to complete 290% (p < 0.001) greater training load than the NT group. This was due to an increased training duration (273%; p < 0.001) in the IT group. Exercise intensity was found to be similar between the NT and IT groups. Compared to the final week of overload training, the taper training load was reduced by 72.5% (p < 0.001) and 39.9% (p < 0.001) in the IT and NT groups, respectively. The distribution of total training load during the 4-week overload period for the IT group was 16.2 ± 10.0%, 39.9 ± 14.1% and 34.9 ± 7.1% for swim, bicycle and run training, respectively. The NT group was 9.9 ± 8.5%, 42.0 ± 11.5% and 48.1 ± 11.4% for swim, bicycle and run training, respectively. Performance tests The 3 kmtt performance of IT group decreased significantly during the 4-week extensive training period from 10:38 ± 01:08 min:s to 10:59 ± 01:04 min:s (p = 0.041) with 6/8 athletes demonstrating performance decrements. Based on this significant decrease in 3 kmtt performance, it can be concluded that the IT group was functionally overreached following the overload training period. 2 In contrast, all athletes in the NT group improved their 3 kmtt-performance from 11:17 ± 00:53 min:s to 10:57 ± 00:53 min:s. Following the 2-week taper, the IT group improved 3 kmtt by 7% (p = 0.05) from 10:59 ± 01:04 min:s to 10:14 ± 01:04 min:s. However, the 2-week recovery period did not significantly improve the 3 kmtt performance of the NT group [10:57 ± 00:53 min:s to 10:52 ± 00:53 min:s]. For additional information

376 A.J. Coutts et al. Table 1 Weekly training load (AU) [mean ± S.D.] during the 6-week training period Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Intensified training 3270 ± 963 c 3731 ± 862 a,c 4269 ± 771 c,d 5626 ± 1395 a,b,c,d 2498 ± 598c a,b 1545 ± 646 a,b,c,d Normal training 1107 ± 602 1587 ± 857 1616 ± 430 1516 ± 703 943 ± 497 a 912 ± 359 a Significantly different to previous measure. b Significantly different amount of change from previous measure compared to NT group. c Significantly different between IT and NT groups. d Significantly different to pre-training (all p < 0.05). on the 3 kmtt performance changes see Coutts et al. 11 The heart rates measured immediately following Stage 3 of the HR submax test decreased throughout the training and recovery period in both the IT and NT groups (p = 0.002). There were between group changes in the HR submax test during the taper. The IT group s performance of the 5BT was significantly decreased from 11.4 ± 1.4 m to 10.5 ± 0.8 m (p = 0.040) during the 4-week overload training period and was restored to pre-training measures 11.5 ± 1.1 m following the 2-week taper. The 5BT performance in the NT group remained relatively constant throughout the 6-week training period [pre-training 11.52 ± 1.01 m, post-training 11.38 ± 1.04 m and following the recovery period 11.49 ± 1.08 m]. Whole group correlations showed that 3 kmtt was significantly correlated with 5BT (r = 0.37, p = 0.003), weekly TL (r = 0.45, p = 0.001; Fig. 1), and Run/BicycleTL (r = 0.27, p = 0.001). 5BT as a whole group was also found to significantly correlate with weekly TL (r = 0.51, p < 0.001; Fig. 2). Physiological tests Differences between the IT and NT groups were found for the change in blood lactate concentration during the incremental treadmill test to exhaustion at 11.5 km h 1 from pre-training to post-recovery (p = 0.023) (Table 2). A significant change between groups was also observed in blood lactate concentration at 11.5 km h 1 from post-recovery to post-training (p = 0.039). Lactate threshold velocity significantly increased from pre-training to posttraining (p < 0.001) and between post-training to post-recovery (p < 0.001) in both IT and NT groups Figure 1 Relationship between change in 3-km timetrial (3 kmtt) performance and change in total training load throughout the 4-week overload and 2-week taper in both IT and NT groups. IT, intensified training; NT, normal training.

Monitoring training 377 Table 2 Changes in physiological parameters [mean ± S.D.] throughout the 6-week investigation Group Pre-training Post-training Recovery Physical characteristics Body mass (kg) IT 70.7 ± 5.2 a 70.9 ± 5.4 a 70.7 ± 5.1 a NT 80.6 ± 7.7 78.6 ± 7.2 78.5 ± 7.4 Skinfolds (mm) IT 69.3 ± 18.1 a 63.0 ± 14.4 a 73.5 ± 19.9 a NT 100.8 ± 28.0 97.4 ± 25.0 101.7 ± 20.6 Age (year) IT 33.4 ± 15.0 NT 27.7 ± 7.6 Maximal oxygen uptake (ml kg 1 min 1 ) IT 54.9 ± 5.6 53.0 ± 6.1 58.2 ± 5.6 NT 52.7 ± 4.7 49.7 ± 5.6 53.2 ± 2.5 VO 2 at 14.5 km h 1 (ml kg 1 min 1 ) IT 45.6 ± 3.2 43.5 ± 3.6 44.3 ± 4.4 NT 45.1 ± 4.8 44.3 ± 3.5 43.0 ± 3.0 Lactate threshold velocity (km h 1 ) IT 14.9 ± 1.6 15.8 ± 1.7 16.4 ± 1.4 NT 13.9 ± 1.2 14.5 ± 1.1 14.9 ± 1.4 Blood lactate concentration (mmol L 1 ) 8.5 km h 1 IT 1.8 ± 0.5 1.9 ± 0.3 2.1 ± 0.4 NT 1.7 ± 0.8 2.0 ± 0.7 2.0 ± 0.8 10.0 km h 1 IT 2.7 ± 0.4 2.4 ± 1.0 2.5 ± 0.6 NT 2.7 ± 0.5 2.3 ± 0.6 2.4 ± 0.6 11.5 km h 1 IT 2.3 ± 0.6 2.2 ± 0.4 2.3 ± 0.7 b,c NT 2.9 ± 0.8 2.5 ± 0.6 2.2 ± 0.5 13.0 km h 1 IT 2.7 ± 0.9 2.3 ± 0.7 2.6 ± 1.1 NT 3.4 ± 0.9 3.1 ± 0.7 2.6 ± 0.9 14.5 km h 1 IT 3.8 ± 1.4 3.1 ± 1.3 3.3 ± 1.4 NT 5.2 ± 1.8 4.5 ± 1.8 3.7 ± 1.3 16.0 km h 1 IT 5.3 ± 2.6 4.2 ± 2.2 4.4 ± 2.0 NT 7.3 ± 2.1 6.5 ± 3.2 6.0 ± 2.9 Maximal IT 9.4 ± 3.1 8.8 ± 2.6 11.8 ± 3.5 NT 11.2 ± 1.5 10.5 ± 2.4 12.4 ± 1.2 Heart rate (bpm) 13.0 km h 1 IT 154.4 ± 16.8 144.3 ± 17.8 148.8 ± 17.5 NT 165.1 ± 18.4 161.3 ± 8.7 158.6 ± 10.4 14.5 km h 1 IT 166.0 ± 14.6 154.3 ± 17.8 c 158.3 ± 16.8 b NT 177.0 ± 13.8 171.9 ± 8.5 168.7 ± 8.4 16.0 km h 1 IT 178.0 ± 11.1 167.6 ± 12 9 c 170.4 ± 14.5 c NT 185.3 ± 8.8 184.9 ± 8.2 177.1 ± 6.5 Maximal IT 186.8 ± 13.4 181.9 ± 17.0 186.4 ± 17.0 NT 195.7 ± 8.1 191.6 ± 8.6 191.7 ± 9.5 a Significantly different to NT group (p < 0.05). b Significantly different amount of change from previous measure compared to NT group (p < 0.05). c Significantly different amount of change from pre-training compared to NT group (p < 0.05). IT, intensified training; NT, normal training.

378 A.J. Coutts et al. Figure 2 Relationship between changes in five-bound test (5BT) and changes in training load throughout both the 4-week overload and 2-week taper in both IT and NT groups. IT, intensified training; NT, normal training. (Table 2). However, no significant differences in lactate threshold were observed between groups. Changes in the La:RPE ratio at 14.5 km h 1 between the NT and IT groups were observed to be significantly different between pre-training and post-recovery (p = 0.037) and between post-training and post-recovery (p = 0.012) (Fig. 3). Table 2 shows that there were significant changes between the groups in heart rate during the incremental treadmill test at 14.5 km h 1 between post-training and pre-training (p = 0.005) and from post-training to post-recovery (p = 0.009). At 16 km h 1 changes in heart rate were significant between post-training and pre-training (p = 0.002) and between pretraining to post-recovery (p = 0.003). No other significant differences in physiological measures between the IT and NT groups were found (Table 2). Figure 4 Daily average of worse than normal responses to DALDA (Part B) for both the IT and NT groups [mean ± S.D.]. IT, intensified training; NT, normal training. Psychological measures No significant differences were observed over time or between the two experimental groups in Part A of the DALDA. However, in Part B of the DALDA, the IT athletes reported a significantly greater number of worse than normal responses in comparison to the NT athletes during the final week of the overload training period (p = 0.031) (Fig. 4). Additionally, the IT group demonstrated a significant decrease in worse than normal responses in the first week of the taper (p = 0.028). No significant changes were observed in better than normal responses to Part B of the DALDA. There were significant correlations between worse than normal responses in Part B of the DALDA and 3 kmtt (r = 0.30, p < 0.05), and the 3-day average training load (r = 0.71, p < 0.001). Discussion Figure 3 Lactate:RPE ratio at 14.5 km h 1 [mean ± S.D.] for both the IT and NT groups at pre-training, posttraining and recovery. a Significantly different amount of change from previous measure compared to NT group; b significantly different amount of change from pretraining compared to NT group (p < 0.05). IT, intensified training; NT, normal training. The ability to monitor acute changes in an athlete s performance may assist in the prevention of non-functional overreaching and the Overtraining Syndrome. However, regular maximal performance testing may be unduly fatiguing and impractical for most athletes. Therefore, this study was designed to examine the effectiveness of several simple tests to reflect changes in 3 kmtt running performance in endurance athletes undergoing either normal or intensified training loads. The present study demonstrated that the DALDA was an effective practical method for monitoring fatigue and recovery. This was evident in the significant increase in worse than normal responses of the IT group to Part B of the DALDA during the overload training period. Importantly, the

Monitoring training 379 DALDA was able to distinguish between adapting (NT) and non-adapting (IT) athletes. These results are in agreement with Halson et al., 20 who also observed a significantly elevated number of worse than normal responses to Part B of the DALDA in functionally overreached eight male cyclists. In this study, there was a weak but significant relationship between the DALDA responses, 3-day average training load and changes in 3 kmtt. Additionally, the worse than normal responses to Part B of the DALDA were also significantly increased with intensified training and decreased with the taper. Combined, these results show that the DALDA may be a useful tool to measure changes in both stress and recovery states of athletes. A link between alterations in the neuromuscular system, running performance and training fatigue has recently been discussed. 21 23 In this study, 5BT was used to monitor changes in neuromuscular performance of the lower limbs. Our justification for choosing the test is that the stretch-shortening cycle recruited during the 5BT is strongly implicated with exercise fatigue 22 and that jump tests have been observed to increase concomitantly with endurance running performance. 17 Moreover, reduced jump performance has been reported during periods of heavy training 21 and vertical jump height has been shown to remain reduced for up to 18 days following ultra-endurance running. 24 In this study, the 5BT results followed changes in 3 kmtt performance and training load in both groups. It appears that the decreased 5BT performance in the IT group following the overload period may be related to repeated exerciseinduced muscle damage and inflammation caused by the increased training. This explanation is supported by the relationships observed between 5BT and total training load (r = 0.45). These findings suggest that changes in the 5BT may be a useful early general indicator of increased neuromuscular fatigue. The HR submax test results showed that, despite significant changes in the submaximal heart rate response of both the IT and NT groups, a clear diagnostic pattern for the detection of overreaching using the HR submax test was not apparent. More importantly, changes in heart rate did not relate to changes in either 3 kmtt performance or training load. Decreases in heart rate during submaximal workloads have previously been suggested as markers of overreaching. 25 However, a reduction in heart rate during exercise may also occur as a positive training response and indicate improvements in cardiovascular efficiency. The similar heart rate response between adapting and non-adapting athletes may explain why no correlation was observed between the HR submax test, training load and performance. These factors, combined with the previously reported high day-to-day variability in the submaximal heart rate response during 20-m shuttle running ( 7 bpm), 26 suggest that either a large increase or decrease in heart rate would be required in order to find a practical and meaningful change in fatigue or recovery. Considering this, we do not recommend the use of submaximal heart rate to predict performance decrements with non-functional overreaching and the Overtraining Syndrome. Changes in various other physiological parameters were also assessed throughout the 6-week study in both the IT and NT groups. In the present study, no useful diagnostic pattern was observed in the maximal oxygen uptake, running economy, lactate threshold, blood lactate concentration, La:RPE ratio or the maximal heart rate of the IT and NT groups, despite significant differences in 3 kmtt performance between the IT and NT groups. This is possibly due to the relatively short training period (4 weeks) used in the present study, which may have been insufficient to induce either a significant increase or decrease in these physiological parameters in previously well-trained athletes. 21 A common problem with using physiological measures to detect overreaching is that some are changed similarly in both NT and IT athletes. We observed this phenomenon in the heart rate, lactate threshold and submaximal blood lactate measures. For instance, an increase in lactate threshold was observed in both the IT and NT groups at the conclusion of the 4-week training period, suggesting improved performance in both groups. However, the increased lactate threshold in the IT group corresponded with poorer 3 kmtt performance. Urhausen et al. 27 reported similar results in overreached endurance athletes where, despite a 27% decrease time to exhaustion, both individual lactate threshold and power output at 4 mmol L 1 lactate increased. These paradoxical findings have previously been attributed to a reduction in the glycolytic capacity of the muscle because of insufficient glycogen stores 28 and/or altered catecholamine responses during intensified training periods. 29 Accordingly, in overreached athletes, lactate accumulation may be delayed, resulting in an apparent improvement of lactate threshold. These results show that physiological measures such as lactate threshold cannot be reliably used independently to differentiate between a positive or negative training effect in endurance athletes.

380 A.J. Coutts et al. Conclusion In summary, the present results show that changes in DALDA and 5BT measures were associated with changes in 3 kmtt performance during periods of overreaching and following a taper. Although the strength of the correlations for these measures was low, we suggest that these simple tests may be useful non-fatiguing measures that can be used to monitor general changes in the fatigue and recovery states of endurance athletes. Future studies should examine the relationships between these practical tests and exercise performance within individual athletes over a longer period to see if these tests are sufficiently sensitive to be used to guide the coach for prescribing training and recovery for individual athletes. Practical applications Psychological questionnaires, such as the Daily Analysis of Life Demands for Athletes, may be useful tools to identify athletes who are susceptible to non-functional overreaching. 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