Blood-Borne Markers of Fatigue in Competitive Athletes – Results from Simulated Training Camps

• DOI: 10.1371/journal.pone.0148810
• Publication Date: 2016-02-18T16:30:10Z
• Authors: Anne Hecksteden; Sabrina Skorski; Sascha Schwindling; Daniel Hammes; Mark Pfeiffer; Michael Kellmann; Alexander Ferrauti; Tim Meyer
• Keywords: Creatine kinase; Venous blood; Overtraining; Blood urea nitrogen

Assessing current fatigue of athletes to fine-tune training prescriptions is a critical task in competitive sports. Blood-borne surrogate markers are widely used despite the scarcity validation trials with representative subjects and interventions. Moreover, differences between modes disciplines (e.g. due eccentric force production or calorie turnover) have rarely been studied within consistent design. Therefore, we investigated blood-borne during after discipline-specific simulated camps. A comprehensive panel blood-born indicators was measured 73 (28 cyclists, 22 team sports, 23 strength) at 3 time-points: run-in resting phase (d 1), 6-day induction 8) following subsequent 2-day recovery period 11). Venous blood samples were collected 8 10 a.m. Courses considered as dependent if significant deviation from baseline present day (Δfatigue) which significantly regresses towards until 11 (Δrecovery). With cycling, course observed for creatine kinase (CK; Δfatigue 54±84 U/l; Δrecovery -60±83 U/l), urea (Δfatigue 11±9 mg/dl; -10±10 mg/dl), free testosterone -1.3±2.1 pg/ml; 0.8±1.5 pg/ml) insulin linke growth factor 1 (IGF-1; -56±28 ng/ml; 53±29 ng/ml). For IGF-1 95% confidence intervals days did not overlap 8. strength high-intensity interval training, respectively, fatigue-dependent courses separated CK (strength: 582±649 -618±419 HIIT: 863±952 -741±842 U/l) only. These results indicate that, markers, changes most accurately reflected by cycling sport players.