@article{SperlichAchtzehndeMareesetal.2016, author = {Sperlich, Billy and Achtzehn, Silvia and de Mar{\´e}es, Markus and von Papen, Henning and Mester, Joachim}, title = {Load management in elite German distance runners during 3-weeks of high-altitude training}, series = {Physiological Reports}, volume = {4}, journal = {Physiological Reports}, number = {12}, doi = {10.14814/phy2.12845}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-171294}, pages = {e12845}, year = {2016}, abstract = {There is a debate on the optimal way of monitoring training loads in elite endurance athletes especially during altitude training camps. In this case report, including nine members of the German national middle distance running team, we describe a practical approach to monitor the psychobiological stress markers during 21 days of altitude training (~2100 m above sea-level) to estimate the training load and to control muscle damage, fatigue, and/or chronic overreaching. Daily examination included: oxygen saturation of hemoglobin, resting heart rate, body mass, body and sleep perception, capillary blood concentration of creatine kinase. Every other day, venous serum concentration of blood urea nitrogen, venous blood concentration of hemoglobin, hematocrit, red and white blood cell were measured. If two or more of the above-mentioned stress markers were beyond or beneath the athlete's normal individual range, the training load of the subsequent training session was reduced. Running speed at 3 mmol L\(^{-1}\) blood lactate (V\(_{3}\)) improved and no athlete showed any signs of underperformance, chronic muscle damage, decrease body and sleep perception as well as activated inflammatory process during the 21 days. The dense screening of biomarkers in the present case study may stimulate further research to identify candidate markers for load monitoring in elite middle- and long-distance runners during a training camp at altitude.}, language = {en} } @article{BeckerSperlichZinneretal.2020, author = {Becker, Manuel and Sperlich, Billy and Zinner, Christoph and Achtzehn, Silvia}, title = {Intra-Individual and Seasonal Variation of Selected Biomarkers for Internal Load Monitoring in U-19 Soccer Players}, series = {Frontiers in Physiology}, volume = {11}, journal = {Frontiers in Physiology}, number = {838}, issn = {1664-042X}, doi = {10.3389/fphys.2020.00838}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-209616}, year = {2020}, abstract = {The aim of this study was to investigate inter-day and -week as well as intra- and inter-individual variation of selected biomarkers in high-performance youth soccer players to assist practitioners interpreting player's internal load to counteract underperformance and unwanted health risks. Eleven male youth soccer players were tested multiple times during two 3-week periods at midpoint (3-wkmid) and at the end (3-wkend) of the first half of a German under-19 1. Bundesliga season. The levels of creatine kinase (CK), urea, and C-reactive protein (CRP) were measured during 3-wkmid and 3-wkend each Monday, Wednesday, and Friday. In 3-wkmid the CK median was 14\% higher (241 vs. 212 U/L) compared to 3-wkend (P = 0.26, ES = 0.16). Overall, the medians of CK, urea (P = 0.59, ES = 0.08), and CRP (P = 0.56, ES = 0.10) during 3-wkmid did not differ to the values of 3-wkend. Daily coefficient of variations (CVs) ranged from 22 to 71\% (CK), 17 to 37\% (urea), and 9 to 164\% (CRP). Individual medians ranged from 101 to 350 U/L (CK), 23 to 50 mg/dL (urea), and 0.6 to 1.1 mg/L (CRP). High intra-individual variability was demonstrated by large intra-individual CVs (medians: CK 50\%, urea 18\%, and CRP 45\%). Our data show (i) large inter-day and inter-week variability of all biomarkers, depending on the external load and (ii) considerable inter- and intra-individual parameter variations. Creatine kinase concentrations could sensitively reflect soccer-specific loads during the season.}, language = {en} } @article{DuekingAchtzehnHolmbergetal.2018, author = {D{\"u}king, Peter and Achtzehn, Silvia and Holmberg, Hans-Christer and Sperlich, Billy}, title = {Integrated framework of load monitoring by a combination of smartphone applications, wearables and point-of-care testing provides feedback that allows individual responsive adjustments to activities of daily living}, series = {Sensors}, volume = {18}, journal = {Sensors}, number = {5}, doi = {10.3390/s18051632}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176506}, pages = {1632}, year = {2018}, abstract = {Athletes schedule their training and recovery in periods, often utilizing a pre-defined strategy. To avoid underperformance and/or compromised health, the external load during training should take into account the individual's physiological and perceptual responses. No single variable provides an adequate basis for planning, but continuous monitoring of a combination of several indicators of internal and external load during training, recovery and off-training as well may allow individual responsive adjustments of a training program in an effective manner. From a practical perspective, including that of coaches, monitoring of potential changes in health and performance should ideally be valid, reliable and sensitive, as well as time-efficient, easily applicable, non-fatiguing and as non-invasive as possible. Accordingly, smartphone applications, wearable sensors and point-of-care testing appear to offer a suitable monitoring framework allowing responsive adjustments to exercise prescription. Here, we outline 24-h monitoring of selected parameters by these technologies that (i) allows responsive adjustments of exercise programs, (ii) enhances performance and/or (iii) reduces the risk for overuse, injury and/or illness.}, language = {en} }