Evaluation Of Performance In Adolescent Runners As A Possible Link To Overtraining

Abstract

Performance is the gold standard to distinguish between desired or undesired training effects (e.g., a performance decline based on overtraining). It is questioned if parameters related to a period of declining performances can be used as predictors of overtraining. PURPOSE To study whether various physiological, hormonal and psychosocial factors are related to performance. METHODS Thirty five adolescent mid-long distance runners (age: 11–19 yrs) were followed during a 7 months training period in which 4 tests were carried out (T1–T4). Performance was established by the Zoladztest. Resting heart rate was registered in the morning (Polar) and saliva cortisol (C) was sampled in the evening and morning (fluorescence immunoassay). Daily hassles, life events, sleep quality, physical enjoyment, and mood scores (POMS) were registered by questionnaires. For further analysis, 8 runners were extracted with an increasing performance (IP) over time, and 8 with an undesired declining performance (DP). RESULTS At baseline (T1), DP had higher vigor scores (2.73 vs 2.20), more daily hassles (28.3 vs 12.6) and tension (1.06 vs 0.40) than IP (t-test for independent samples, mean values, p<0.05). At T2 and T3, DP showed also significantly more depression (T2: 0.95 vs 0.19; T3: 1.06 vs 0.13), anger (T2: 1.26 vs 0.57; T3: 1.51 vs 0.49) and tension (T2: 1.00 vs 0.52; T3: 1.19 vs 0.36). All other factors showed no significant difference between DP and IP. Only in male runners, relatively high morning C levels were maintained in DP from T1 till T4 (22.9, 18.4, 18.0, 15.9 nmol/l), whereas in IP morning levels increased from T1 till T3 (15.5 to 20.2 nmol/l) and declined at T4 (13.3 nmol/l). This indicates that morning C followed desired training effects in IP, and not in DP. CONCLUSIONS Experienced stress during a training season is influenced by differences in predisposition of total stress adaptation. Subjective feelings may be the most reliable predictors of overtraining.