Changes In Markers Of Recovery, Readiness, And Nutritional Status In Division I Female Soccer Players Over The First Half Of The Competitive Season

Abstract

Athletes strive for a competitive edge through proper management and monitoring of training. Biomarkers are emerging as a potential tool for optimally assessing player health, recovery, and readiness. PURPOSE: To evaluate changes in various biomarkers associated with breakdown, recovery, and nutritional status in female collegiate soccer players in the first half of a competitive season. METHODS: Division I female collegiate soccer players (N=29; Mage= 20 ±1.3 yrs; Mweight= 64.7 ± 6.3 kg; Mheight= 166.8 ± 7.2 cm; M%BF= 22.0 ± 3.9 %) participated in blood draws at the start of preseason (T1) the first quarter of the season (T2) and at the midpoint (T3). The athletes arrived fasted and euhydrated the morning after a game. Hematocrit (HCT), IL-6, creatine kinase (CK), total cortisol (CORT), iron (Fe), Vit-D, omega-3-6 ratio (OMG36), and prolactin (PRL) were assessed. All players were monitored for training load using the Polar Team2 System. RESULTS: There were significant changes in HCT, Fe, OMG36, CK, CORT, and PRL (P< .05) over the first half of the season. HCT, Fe, and OMG36 each decreased significantly from T1 to T2 (ΔHCT = -1.4 ± 0.4 %; ΔFe=-45.9 ± 12.9 mcg/dL, ΔOMG36 = -1.8 ± 0.6) and remained significantly lowered at T3, P<.05. CK increased from T1 to T2 (ΔCK = 112.3 ± 41.8 U/L, P<.05) before returning towards baseline by T3, while CORT increased from T1 to T3 (ΔCORT = 6.9 ± 1.0 mg/dL, P<.05). Both markers were above clinical norms in-season. PRL significantly increase from T1 to T3 (5.8 ± 1.5 ng/ml, P<.05). There were no changes in daily training load, though accumulated training load significantly decreased (P< .05) from T2 (3691.9 ± 187.8) to T3 (2566.9 ± 133.9). CONCLUSION: The significant increases in CK, CORT, and PRL are consistent with overreaching and indicate incomplete recovery, despite typical training loads. While monitoring training load is a useful tool to account for the daily sport demands, the biomarkers appear to provide critical additional information to account for cumulative strain and recovery. Based on the changes in Fe and OMG36, nutritional insufficiencies may be partly responsible for impaired recovery. These results are consistent with subjective observations in team performance and provide support for the inclusion of biomarkers in comprehensive athlete monitoring. Supported by Quest Diagnostics