@article{DuekingGiessingFrenkeletal.2020, author = {D{\"u}king, Peter and Giessing, Laura and Frenkel, Marie Ottilie and Koehler, Karsten and Holmberg, Hans-Christer and Sperlich, Billy}, title = {Wrist-Worn Wearables for Monitoring Heart Rate and Energy Expenditure While Sitting or Performing Light-to-Vigorous Physical Activity: Validation Study}, series = {JMIR mhealth and uhealth}, volume = {8}, journal = {JMIR mhealth and uhealth}, number = {5}, doi = {10.2196/16716}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229413}, year = {2020}, abstract = {Background: Physical activity reduces the incidences of noncommunicable diseases, obesity, and mortality, but an inactive lifestyle is becoming increasingly common. Innovative approaches to monitor and promote physical activity are warranted. While individual monitoring of physical activity aids in the design of effective interventions to enhance physical activity, a basic prerequisite is that the monitoring devices exhibit high validity. Objective: Our goal was to assess the validity of monitoring heart rate (HR) and energy expenditure (EE) while sitting or performing light-to-vigorous physical activity with 4 popular wrist-worn wearables (Apple Watch Series 4, Polar Vantage V, Garmin Fenix 5, and Fitbit Versa). Methods: While wearing the 4 different wearables, 25 individuals performed 5 minutes each of sitting, walking, and running at different velocities (ie, 1.1 m/s, 1.9 m/s, 2.7 m/s, 3.6 m/s, and 4.1 m/s), as well as intermittent sprints. HR and EE were compared to common criterion measures: Polar-H7 chest belt for HR and indirect calorimetry for EE. Results: While monitoring HR at different exercise intensities, the standardized typical errors of the estimates were 0.09-0.62, 0.13-0.88, 0.62-1.24, and 0.47-1.94 for the Apple Watch Series 4, Polar Vantage V, Garmin Fenix 5, and Fitbit Versa, respectively. Depending on exercise intensity, the corresponding coefficients of variation were 0.9\%-4.3\%, 2.2\%-6.7\%, 2.9\%-9.2\%, and 4.1\%-19.1\%, respectively, for the 4 wearables. While monitoring EE at different exercise intensities, the standardized typical errors of the estimates were 0.34-1.84, 0.32-1.33, 0.46-4.86, and 0.41-1.65 for the Apple Watch Series 4, Polar Vantage V, Garmin Fenix 5, and Fitbit Versa, respectively. Depending on exercise intensity, the corresponding coefficients of variation were 13.5\%-27.1\%, 16.3\%-28.0\%, 15.9\%-34.5\%, and 8.0\%-32.3\%, respectively. Conclusions: The Apple Watch Series 4 provides the highest validity (ie, smallest error rates) when measuring HR while sitting or performing light-to-vigorous physical activity, followed by the Polar Vantage V, Garmin Fenix 5, and Fitbit Versa, in that order. The Apple Watch Series 4 and Polar Vantage V are suitable for valid HR measurements at the intensities tested, but HR data provided by the Garmin Fenix 5 and Fitbit Versa should be interpreted with caution due to higher error rates at certain intensities. None of the 4 wrist-worn wearables should be employed to monitor EE at the intensities and durations tested."}, language = {en} } @article{McIlroyPassfieldHolmbergetal.2021, author = {McIlroy, Benjamin and Passfield, Louis and Holmberg, Hans-Christer and Sperlich, Billy}, title = {Virtual training of endurance cycling - A summary of strengths, weaknesses, opportunities and threats}, series = {Frontiers in Sports and Active Living}, volume = {3}, journal = {Frontiers in Sports and Active Living}, doi = {10.3389/fspor.2021.631101}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-258876}, year = {2021}, abstract = {Virtual online training has emerged as one of the top 20 worldwide fitness trends for 2021 and continues to develop rapidly. Although this allows the cycling community to engage in virtual training and competition, critical evaluation of virtual training platforms is limited. Here, we discuss the strengths, weaknesses, opportunities and threats associated with virtual training technology and cycling in an attempt to enhance awareness of such aspects. Strengths include immersive worlds, innovative drafting mechanics, and versatility. Weaknesses include questionable data accuracy, inadequate strength and reliability of power-speed algorithms. Opportunities exist for expanding strategic partnerships with major cycling races, brands, and sponsors and improving user experience with the addition of video capture and "e-coaching." Threats are present in the form of cheating during competition, and a lack of uptake and acceptance by a broader community.}, language = {en} } @article{WallmannSperlichDuekingMuelleretal.2022, author = {Wallmann-Sperlich, Birgit and D{\"u}king, Peter and M{\"u}ller, Miriam and Frob{\"o}se, Ingo and Sperlich, Billy}, title = {Type and intensity distribution of structured and incidental lifestyle physical activity of students and office workers: a retrospective content analysis}, series = {BMC Public Health}, volume = {22}, journal = {BMC Public Health}, doi = {10.1186/s12889-022-12999-z}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-301217}, year = {2022}, abstract = {Background Physical activity (PA) guidelines acknowledge the health benefits of regular moderate-to-vigorous physical activity (MVPA) regardless of bout duration. However, little knowledge exists concerning the type and intensity distribution of structured and incidental lifestyle PA of students and office workers. The present study aimed to i) assess the duration and distribution of intensity of MVPAs during waking hours ≥50\% of heart rate reserve (HRR), ii) to identify the type of PA through diary assessment, iii) to assign these activities into structured and lifestyle incidental PA, and iv) to compare this information between students and office workers. Methods Twenty-three healthy participants (11 students, 12 office workers) recorded heart rate (HR) with a wrist-worn HR monitor (Polar M600) and filled out a PA diary throughout seven consecutive days (i.e. ≥ 8 waking h/day). Relative HR zones were calculated, and PA diary information was coded using the Compendium of PA. We matched HR data with the reported PA and identified PA bouts during waking time ≥ 50\% HRR concerning duration, HRR zone, type of PA, and assigned each activity to incidental and structured PA. Descriptive measures for time spend in different HRR zones and differences between students and office workers were calculated. Results In total, we analyzed 276.894 s (76 h 54 min 54 s) of waking time in HRR zones ≥50\% and identified 169 different types of PA. The participants spend 31.9 ± 27.1 min/day or 3.9 ± 3.2\% of their waking time in zones of ≥50\% HRR with no difference between students and office workers (p > 0.01). The proportion of assigned incidental lifestyle PA was 76.9 ± 22.5\%. Conclusions The present study provides initial insights regarding the type, amount, and distribution of intensity of structured and incidental lifestyle PA ≥ 50\% HRR. Findings show a substantial amount of incidental lifestyle PA during waking hours and display the importance of promoting a physically active lifestyle. Future research could employ ambulatory assessments with integrated electronic diaries to detect information on the type and context of MVPA during the day.}, language = {en} } @article{StoegglSperlich2015, author = {St{\"o}ggl, Thomas L. and Sperlich, Billy}, title = {The training intensity distribution among well-trained and elite endurance athletes}, series = {Frontiers in Physiology}, volume = {6}, journal = {Frontiers in Physiology}, number = {295}, doi = {10.3389/fphys.2015.00295}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-138883}, year = {2015}, abstract = {Researchers have retrospectively analyzed the training intensity distribution (TID) of nationally and internationally competitive athletes in different endurance disciplines to determine the optimal volume and intensity for maximal adaptation. The majority of studies present a "pyramidal" TID with a high proportion of high volume, low intensity training (HVLIT). Some world-class athletes appear to adopt a so-called "polarized" TID (i.e., significant \% of HVLIT and high intensity training) during certain phases of the season. However, emerging prospective randomized controlled studies have demonstrated superior responses of variables related to endurance when applying a polarized TID in well-trained and recreational individuals when compared with a TID that emphasizes HVLIT or threshold training. The aims of the present review are to: (1) summarize the main responses of retrospective and prospective studies exploring TID; (2) provide a systematic overview on TIDs during preparation, pre-competition, and competition phases in different endurance disciplines and performance levels; (3) address whether one TID has demonstrated greater efficacy than another; and (4) highlight research gaps in an effort to direct future scientific studies.}, language = {en} } @article{SperlichHolmberg2017, author = {Sperlich, Billy and Holmberg, Hans-Christer}, title = {The responses of elite athletes to exercise: an all-day, 24-h integrative view is required!}, series = {Frontiers in Physiology}, volume = {8}, journal = {Frontiers in Physiology}, number = {564}, doi = {10.3389/fphys.2017.00564}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158655}, year = {2017}, abstract = {No abstract available.}, language = {en} } @article{SperlichMatzkaHolmberg2023, author = {Sperlich, Billy and Matzka, Manuel and Holmberg, Hans-Christer}, title = {The proportional distribution of training by elite endurance athletes at different intensities during different phases of the season}, series = {Frontiers in Sports and Active Living}, volume = {5}, journal = {Frontiers in Sports and Active Living}, doi = {10.3389/fspor.2023.1258585}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-357988}, year = {2023}, abstract = {The present review examines retrospective analyses of training intensity distribution (TID), i.e., the proportion of training at moderate (Zone 1, Z1), heavy (Z2) and severe (Z3) intensity by elite-to-world-class endurance athletes during different phases of the season. In addition, we discuss potential implications of our findings for research in this field, as well as for training by these athletes. Altogether, we included 175 TIDs, of which 120 quantified exercise intensity on the basis of heart rate and measured time-in-zone or employed variations of the session goal approach, with demarcation of zones of exercise intensity based on physiological parameters. Notably, 49\% of the TIDs were single-case studies, predominantly concerning cross-country skiing and/or the biathlon. Eighty-nine TIDs were pyramidal (Z1 > Z2 > Z3), 65 polarized (Z1 > Z3 > Z2) and 8 "threshold" (Z2 > Z1 = Z3). However, these relative numbers varied between sports and the particular phases of the season. In 91\% (n = 160) of the TIDs >60\% of the endurance exercise was of low intensity. Regardless of the approach to quantification or phase of the season, cyclists and swimmers were found to perform a lower proportion of exercise in Z1 (<72\%) and higher proportion in Z2 (>16\%) than athletes involved in the triathlon, speed skating, rowing, running, cross-country skiing or biathlon (>80\% in Z1 and <12\% in Z2 in all these cases). For most of the athletes their proportion of heavy-to-severe exercise was higher during the period of competition than during the preparatory phase, although with considerable variability between sports. In conclusion, the existing literature in this area does not allow general conclusions to be drawn. The methods utilized for quantification vary widely and, moreover, contextual information concerning the mode of exercise, environmental conditions, and biomechanical aspects of the exercise is often lacking. Therefore, we recommend a more comprehensive approach in connection with future investigations on the TIDs of athletes involved in different endurance sports.}, language = {en} } @article{DuekingHolmbergSperlich2018, author = {D{\"u}king, Peter and Holmberg, Hans-Christer and Sperlich, Billy}, title = {The potential usefulness of virtual reality systems for athletes: a short SWOT analysis}, series = {Frontiers in Physiology}, volume = {9}, journal = {Frontiers in Physiology}, number = {128}, doi = {10.3389/fphys.2018.00128}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176178}, year = {2018}, abstract = {No abstract available.}, language = {en} } @article{BornZinnerSperlich2017, author = {Born, Dennis-Peter and Zinner, Christoph and Sperlich, Billy}, title = {The mucosal immune function is not compromised during a period of high-intensity interval training. Is it time to reconsider an old assumption?}, series = {Frontiers in Physiology}, volume = {8}, journal = {Frontiers in Physiology}, number = {485}, doi = {10.3389/fphys.2017.00485}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158025}, year = {2017}, abstract = {Purpose: The aim of the study was to evaluate the mucosal immune function and circadian variation of salivary cortisol, Immunoglobin-A (sIgA) secretion rate and mood during a period of high-intensity interval training (HIIT) compared to long-slow distance training (LSD). Methods: Recreational male runners (n = 28) completed nine sessions of either HIIT or LSD within 3 weeks. The HIIT involved 4 × 4 min of running at 90-95\% of maximum heart rate interspersed with 3 min of active recovery while the LSD comprised of continuous running at 70-75\% of maximum heart rate for 60-80 min. The psycho-immunological stress-response was investigated with a full daily profile of salivary cortisol and immunoglobin-A (sIgA) secretion rate along with the mood state on a baseline day, the first and last day of training and at follow-up 4 days after the last day of training. Before and after the training period, each athlete's running performance and peak oxygen uptake (V·O\(_{2peak}\)) was determined with an incremental exercise test. Results: The HIIT resulted in a longer time-to-exhaustion (P = 0.02) and increased V·O\(_{2peak}\) compared to LSD (P = 0.01). The circadian variation of sIgA secretion rate showed highest values in the morning immediately after waking up followed by a decrease throughout the day in both groups (P < 0.05). With HIIT, the wake-up response of sIgA secretion rate was higher on the last day of training (P < 0.01) as well as the area under the curve (AUC\(_{G}\)) higher on the first and last day of training and follow-up compared to the LSD (P = 0.01). Also the AUC\(_{G}\) for the sIgA secretion rate correlated with the increase in V·O\(_{2peak}\) and running performance. The AUC\(_{G}\) for cortisol remained unaffected on the first and last day of training but increased on the follow-up day with both, HIIT and LSD (P < 0.01). Conclusion: The increased sIgA secretion rate with the HIIT indicates no compromised mucosal immune function compared to LSD and shows the functional adaptation of the mucosal immune system in response to the increased stress and training load of nine sessions of HIIT.}, language = {en} } @article{SperlichDuekingLeppichetal.2023, author = {Sperlich, Billy and D{\"u}king, Peter and Leppich, Robert and Holmberg, Hans-Christer}, title = {Strengths, weaknesses, opportunities, and threats associated with the application of artificial intelligence in connection with sport research, coaching, and optimization of athletic performance: a brief SWOT analysis}, series = {Frontiers in Sports and Active Living}, volume = {5}, journal = {Frontiers in Sports and Active Living}, doi = {10.3389/fspor.2023.1258562}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-357973}, year = {2023}, abstract = {Here, we performed a non-systematic analysis of the strength, weaknesses, opportunities, and threats (SWOT) associated with the application of artificial intelligence to sports research, coaching and optimization of athletic performance. The strength of AI with regards to applied sports research, coaching and athletic performance involve the automation of time-consuming tasks, processing and analysis of large amounts of data, and recognition of complex patterns and relationships. However, it is also essential to be aware of the weaknesses associated with the integration of AI into this field. For instance, it is imperative that the data employed to train the AI system be both diverse and complete, in addition to as unbiased as possible with respect to factors such as the gender, level of performance, and experience of an athlete. Other challenges include e.g., limited adaptability to novel situations and the cost and other resources required. Opportunities include the possibility to monitor athletes both long-term and in real-time, the potential discovery of novel indicators of performance, and prediction of risk for future injury. Leveraging these opportunities can transform athletic development and the practice of sports science in general. Threats include over-dependence on technology, less involvement of human expertise, risks with respect to data privacy, breaching of the integrity and manipulation of data, and resistance to adopting such new technology. Understanding and addressing these SWOT factors is essential for maximizing the benefits of AI while mitigating its risks, thereby paving the way for its successful integration into sport science research, coaching, and optimization of athletic performance.}, language = {en} } @article{ZinnerSperlichKruegeretal.2015, author = {Zinner, Christoph and Sperlich, Billy and Krueger, Malte and Focke, Tim and Reed, Jennifer and Mester, Joachim}, title = {Strength, Endurance, Throwing Velocity and in-Water Jump Performance of Elite German Water Polo Players}, series = {Journal of Human Kinetics}, volume = {45}, journal = {Journal of Human Kinetics}, doi = {10.1515/hukin-2015-0015}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148812}, pages = {149-156}, year = {2015}, abstract = {The purpose of this study was threefold: 1) to assess the eggbeater kick and throwing performance using a number of water polo specific tests, 2) to explore the relation between the eggbeater kick and throwing performance, and 3) to investigate the relation between the eggbeater kick in the water and strength tests performed in a controlled laboratory setting in elite water polo players. Fifteen male water polo players of the German National Team completed dynamic and isometric strength tests for muscle groups (adductor, abductor, abdominal, pectoralis) frequently used during water polo. After these laboratory strength tests, six water polo specific in-water tests were conducted. The eggbeater kick assessed leg endurance and agility, maximal throwing velocity and jump height. A 400 m test and a sprint test examined aerobic and anaerobic performance. The strongest correlation was found between jump height and arm length (p < 0.001, r = 0.89). The laboratory diagnostics of important muscles showed positive correlations with the results of the in-water tests (p < 0.05, r = 0.52-0.70). Muscular strength of the adductor, abdominal and pectoralis muscles was positively related to in-water endurance agility as assessed by the eggbeater kick (p < 0.05; r = 0.53-0.66). Findings from the current study emphasize the need to assess indices of water polo performance both in and out of the water as well as the relation among these parameters to best assess the complex profile of water polo players.}, language = {en} } @article{SarebanWinkertSperlichetal.2018, author = {Sareban, Mahdi and Winkert, Kay and Sperlich, Billy and Berger, Marc M. and Niebauer, Josef and Steinacker, J{\"u}rgen M. and Treff, Gunnar}, title = {Speckle tracking-derived bi-atrial strain before and after eleven weeks of training in elite rowers}, series = {Scientific Reports}, volume = {8}, journal = {Scientific Reports}, doi = {10.1038/s41598-018-32542-8}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227362}, pages = {14300, 1-9}, year = {2018}, abstract = {The left (LA) and right (RA) atria undergo adaptive remodeling in response to hemodynamic stress not only induced by endurance exercise but also as part of several cardiovascular diseases thereby confounding differential diagnosis. Echocardiographic assessment of the atria with novel speckle tracking (STE)-derived variables broadens the diagnostic spectrum compared to conventional analyses and has the potential to differentiate physiologic from pathologic changes. The purpose of this study was to assess and categorize baseline values of bi-atrial structure and function in elite rowers according to recommended cutoffs, and to assess the cardiac changes occurring with endurance training. Therefore, fifteen elite rowers underwent 2D-echocardiographic analysis of established variables of cardiac structure and function as well as STE-derived variables of bi-atrial function. Measurements were performed at baseline and after eleven weeks of extensive training. 40\% of athletes displayed mildly enlarged LA and 47\% mildly enlarged RA at baseline, whereas no athlete fell below the lower reference values of LA and RA reservoir strain. Average power during a 2000 m ergometer rowing test (P2000 m) improved from 426 +/- 39 W to 442 +/- 34 W (p = 0.010) but there were no changes of echocardiographic variables following training. In elite rowers, longitudinal bi-atrial strain assessment indicates normal resting function of structurally enlarged atria and thereby may assist to differentiate between exercise-induced versus disease-associated structural cardiac changes in which function is commonly impaired.}, language = {en} } @article{DavidsonDuekingZinneretal.2020, author = {Davidson, Padraig and D{\"u}king, Peter and Zinner, Christoph and Sperlich, Billy and Hotho, Andreas}, title = {Smartwatch-Derived Data and Machine Learning Algorithms Estimate Classes of Ratings of Perceived Exertion in Runners: A Pilot Study}, series = {Sensors}, volume = {20}, journal = {Sensors}, number = {9}, issn = {1424-8220}, doi = {10.3390/s20092637}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-205686}, year = {2020}, abstract = {The rating of perceived exertion (RPE) is a subjective load marker and may assist in individualizing training prescription, particularly by adjusting running intensity. Unfortunately, RPE has shortcomings (e.g., underreporting) and cannot be monitored continuously and automatically throughout a training sessions. In this pilot study, we aimed to predict two classes of RPE (≤15 "Somewhat hard to hard" on Borg's 6-20 scale vs. RPE >15 in runners by analyzing data recorded by a commercially-available smartwatch with machine learning algorithms. Twelve trained and untrained runners performed long-continuous runs at a constant self-selected pace to volitional exhaustion. Untrained runners reported their RPE each kilometer, whereas trained runners reported every five kilometers. The kinetics of heart rate, step cadence, and running velocity were recorded continuously ( 1 Hz ) with a commercially-available smartwatch (Polar V800). We trained different machine learning algorithms to estimate the two classes of RPE based on the time series sensor data derived from the smartwatch. Predictions were analyzed in different settings: accuracy overall and per runner type; i.e., accuracy for trained and untrained runners independently. We achieved top accuracies of 84.8 \% for the whole dataset, 81.8 \% for the trained runners, and 86.1 \% for the untrained runners. We predict two classes of RPE with high accuracy using machine learning and smartwatch data. This approach might aid in individualizing training prescriptions.}, language = {en} } @article{SperlichBeckerHothoetal.2017, author = {Sperlich, Billy and Becker, Martin and Hotho, Andreas and Wallmann-Sperlich, Birgit and Sareban, Mahdi and Winkert, Kay and Steinacker, J{\"u}rgen M. and Treff, Gunnar}, title = {Sedentary behavior among national elite rowers during off-training — a pilot study}, series = {Frontiers in Physiology}, volume = {8}, journal = {Frontiers in Physiology}, number = {655}, doi = {10.3389/fphys.2017.00655}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158753}, year = {2017}, abstract = {The aim of this pilot study was to analyze the off-training physical activity (PA) profile in national elite German U23 rowers during 31 days of their preparation period. The hours spent in each PA category (i.e., sedentary: <1.5 metabolic equivalents (MET); light physical activity: 1.5-3 MET; moderate physical activity: 3-6 MET and vigorous intense physical activity: >6 MET) were calculated for every valid day (i.e., >480 min of wear time). The off-training PA during 21 weekdays and 10 weekend days of the final 11-week preparation period was assessed by the wrist-worn multisensory device Microsoft Band II (MSBII). A total of 11 rowers provided valid data (i.e., >480 min/day) for 11.6 week days and 4.8 weekend days during the 31 days observation period. The average sedentary time was 11.63 ± 1.25 h per day during the week and 12.49 ± 1.10 h per day on the weekend, with a tendency to be higher on the weekend compared to weekdays (p = 0.06; d = 0.73). The average time in light, moderate and vigorous PA during the weekdays was 1.27 ± 1.15, 0.76 ± 0.37, 0.51 ± 0.44 h per day, and 0.67 ± 0.43, 0.59 ± 0.37, 0.53 ± 0.32 h per weekend day. Light physical activity was higher during weekdays compared to the weekend (p = 0.04; d = 0.69). Based on our pilot study of 11 national elite rowers we conclude that rowers display a considerable sedentary off-training behavior of more than 11.5 h/day.}, language = {en} } @article{BornKunzSperlich2017, author = {Born, Dennis-Peter and Kunz, Philipp and Sperlich, Billy}, title = {Reliability and validity of an agility-like incremental exercise test with multidirectional change-of-direction movements in response to a visual stimulus}, series = {Physiological Reports}, volume = {5}, journal = {Physiological Reports}, number = {9}, doi = {10.14814/phy2.13275}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-158265}, pages = {e13275}, year = {2017}, abstract = {The aim of the study was to evaluate the reliability and validity of cardiorespiratory and metabolic variables, that is, peak oxygen uptake (V'O\(_{2peak}\)) and heart rate (HR\(_{peak}\)), obtained from an agility-like incremental exercise test for team sport athletes. To investigate the test-retest reliability, 25 team sport athletes (age: 22 ± 3 years, body mass: 75 ± 7 kg, height: 182 ± 6 cm) performed an agility-like incremental exercise test on the SpeedCourt (SC) system incorporating multidirectional change-of-direction (COD) movements twice. For each step of the incremental SC test, the athletes covered a 40-m distance interspersed with a 10-sec rest period. Each 40 m distance was split into short sprints (2.25-6.36 m) separated by multidirectional COD movements (0°-180°), which were performed in response to an external visual stimulus. All performance and physiological data were validated with variables obtained from a ramp-like treadmill and Yo-Yo intermittent recovery level 2 test (Yo-Yo IR2). The incremental SC test revealed high test-retest reliability for the time to exhaustion (ICC = 0.85, typical error [TE] = 0.44, and CV\% = 3.88), V'O\(_{2peak}\), HR\(_{peak}\), ventilation, and breathing frequency (ICC = 0.84, 0.72, 0.89, 0.77, respectively). The time to exhaustion (r = 0.50, 0.74) of the incremental SC test as well as the peak values for V'O\(_{2}\) (r = 0.59, 0.52), HR (r = 0.75, 0.78), ventilation (r = 0.57, 0.57), and breathing frequency (r = 0.68, 0.68) were significantly correlated (P ≤ 0.01) with the ramp-like treadmill test and the Yo-Yo IR2, respectively. The incremental SC test represents a reliable and valid method to assess peak values for V'O\(_{2}\) and HR with respect to the specific demand of team sport match play by incorporating multidirectional COD movements, decision making, and cognitive components.}, language = {en} } @article{DuekingFussHolmbergetal.2018, author = {D{\"u}king, Peter and Fuss, Franz Konstantin and Holmberg, Hans-Christer and Sperlich, Billy}, title = {Recommendations for assessment of the reliability, sensitivity, and validity of data provided by wearable sensors designed for monitoring physical activity}, series = {JMIR Mhealth and Uhealth}, volume = {6}, journal = {JMIR Mhealth and Uhealth}, number = {4}, doi = {10.2196/mhealth.9341}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176202}, pages = {e102}, year = {2018}, abstract = {Although it is becoming increasingly popular to monitor parameters related to training, recovery, and health with wearable sensor technology (wearables), scientific evaluation of the reliability, sensitivity, and validity of such data is limited and, where available, has involved a wide variety of approaches. To improve the trustworthiness of data collected by wearables and facilitate comparisons, we have outlined recommendations for standardized evaluation. We discuss the wearable devices themselves, as well as experimental and statistical considerations. Adherence to these recommendations should be beneficial not only for the individual, but also for regulatory organizations and insurance companies.}, language = {en} } @article{SperlichDeClerckZinneretal.2018, author = {Sperlich, Billy and De Clerck, Ine and Zinner, Christoph and Holmberg,, Hans-Christer and Wallmann-Sperlich, Birgit}, title = {Prolonged sitting interrupted by 6-min of high-intensity exercise: circulatory, metabolic, hormonal, thermal, cognitive, and perceptual responses}, series = {Frontiers in Physiology}, volume = {9}, journal = {Frontiers in Physiology}, number = {1279}, doi = {10.3389/fphys.2018.01279}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177307}, year = {2018}, abstract = {The aim was to examine certain aspects of circulatory, metabolic, hormonal, thermoregulatory, cognitive, and perceptual responses while sitting following a brief session of high-intensity interval exercise. Twelve students (five men; age, 22 ± 2 years) performed two trials involving either simply sitting for 180 min (SIT) or sitting for this same period with a 6-min session of high-intensity exercise after 60 min (SIT+HIIT). At T\(_0\) (after 30 min of resting), T\(_1\) (after a 20-min breakfast), T\(_2\) (after sitting for 1 h), T\(_3\) (immediately after the HIIT), T\(_4\), T\(_5\), T\(_6\), and T\(_7\) (30, 60, 90, and 120 min after the HIIT), circulatory, metabolic, hormonal, thermoregulatory, cognitive, and perceptual responses were assessed. The blood lactate concentration (at T\(_3\)-T\(_5\)), heart rate (at T\(_3\)-T\(_6\)), oxygen uptake (at T\(_3\)-T\(_7\)), respiratory exchange ratio, and sensations of heat (T\(_3\)-T\(_5\)), sweating (T\(_3\), T\(_4\)) and odor (T\(_3\)), as well as perception of vigor (T\(_3\)-T\(_6\)), were higher and the respiratory exchange ratio (T\(_4\)-T\(_7\)) and mean body and skin temperatures (T\(_3\)) lower in the SIT+HIIT than the SIT trial. Levels of blood glucose and salivary cortisol, cerebral oxygenation, and feelings of anxiety/depression, fatigue or hostility, as well as the variables of cognitive function assessed by the Stroop test did not differ between SIT and SIT+HIIT. In conclusion, interruption of prolonged sitting with a 6-min session of HIIT induced more pronounced circulatory and metabolic responses and improved certain aspects of perception, without affecting selected hormonal, thermoregulatory or cognitive functions.}, language = {en} } @article{DuekingZinnerReedetal.2020, author = {D{\"u}king, Peter and Zinner, Christoph and Reed, Jennifer L. and Holmberg, Hans-Christer and Sperlich, Billy}, title = {Predefined vs data-guided training prescription based on autonomic nervous system variation: A systematic review}, series = {Scandinavian Journal of Medicine \& Science in Sports}, volume = {30}, journal = {Scandinavian Journal of Medicine \& Science in Sports}, number = {12}, doi = {10.1111/sms.13802}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-217893}, pages = {2291 -- 2304}, year = {2020}, abstract = {Monitoring variations in the functioning of the autonomic nervous system may help personalize training of runners and provide more pronounced physiological adaptations and performance improvements. We systematically reviewed the scientific literature comparing physiological adaptations and/or improvements in performance following training based on responses of the autonomic nervous system (ie, changes in heart rate variability) and predefined training. PubMed, SPORTDiscus, and Web of Science were searched systematically in July 2019. Keywords related to endurance, running, autonomic nervous system, and training. Studies were included if they (a) involved interventions consisting predominantly of running training; (b) lasted at least 3 weeks; (c) reported pre- and post-intervention assessment of running performance and/or physiological parameters; (d) included an experimental group performing training adjusted continuously on the basis of alterations in HRV and a control group; and (e) involved healthy runners. Five studies involving six interventions and 166 participants fulfilled our inclusion criteria. Four HRV-based interventions reduced the amount of moderate- and/or high-intensity training significantly. In five interventions, improvements in performance parameters (3000 m, 5000 m, Loadmax, Tlim) were more pronounced following HRV-based training. Peak oxygen uptake (VO\(_{2peak}\)) and submaximal running parameters (eg, LT1, LT2) improved following both HRV-based and predefined training, with no clear difference in the extent of improvement in VO\(_{2peak}\). Submaximal running parameters tended to improve more following HRV-based training. Research findings to date have been limited and inconsistent. Both HRV-based and predefined training improve running performance and certain submaximal physiological adaptations, with effects of the former training tending to be greater.}, language = {en} } @article{StoegglSperlich2014, author = {St{\"o}ggl, Thomas and Sperlich, Billy}, title = {Polarized training has greater impact on key endurance variables than threshold, high intensity, or high volume training}, series = {Frontiers in Physiology}, volume = {5}, journal = {Frontiers in Physiology}, number = {33}, doi = {10.3389/fphys.2014.00033}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-117007}, year = {2014}, abstract = {Endurance athletes integrate four conditioning concepts in their training programs: high-volume training (HVT), "threshold-training" (THR), high-intensity interval training (HIIT) and a combination of these aforementioned concepts known as polarized training (POL). The purpose of this study was to explore which of these four training concepts provides the greatest response on key components of endurance performance in well-trained endurance athletes. Methods: Forty eight runners, cyclists, triathletes, and cross-country skiers (peak oxygen uptake: (VO2peak): 62.6 ± 7.1 mL·min-1·kg-1) were randomly assigned to one of four groups performing over 9 weeks. An incremental test, work economy and a VO2peak tests were performed. Training intensity was heart rate controlled. Results: POL demonstrated the greatest increase in VO2peak (+6.8 ml·min·kg-1 or 11.7\%, P < 0.001), time to exhaustion during the ramp protocol (+17.4\%, P < 0.001) and peak velocity/power (+5.1\%, P < 0.01). Velocity/power at 4 mmol·L-1 increased after POL (+8.1\%, P < 0.01) and HIIT (+5.6\%, P < 0.05). No differences in pre- to post-changes of work economy were found between the groups. Body mass was reduced by 3.7\% (P < 0.001) following HIIT, with no changes in the other groups. With the exception of slight improvements in work economy in THR, both HVT and THR had no further effects on measured variables of endurance performance (P > 0.05). Conclusion: POL resulted in the greatest improvements in most key variables of endurance performance in well-trained endurance athletes. THR or HVT did not lead to further improvements in performance related variables.}, language = {en} } @article{BornZinnerDuekingetal.2016, author = {Born, Dennis-Peter and Zinner, Christoph and D{\"u}king, Peter and Sperlich, Billy}, title = {Multi-Directional Sprint Training Improves Change-Of-Direction Speed and Reactive Agility in Young Highly Trained Soccer Players}, series = {Journal of Sports Science and Medicine}, volume = {15}, journal = {Journal of Sports Science and Medicine}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-146866}, pages = {314-319}, year = {2016}, abstract = {The aim of this study was to evaluate the effect of a repeated sprint training with multi-directional change-of-direction (COD) movements (RSmulti) compared to repeated shuttle sprints (RSS) on variables related to COD speed and reactive agility. Nineteen highly-trained male U15 soccer players were assigned into two groups performing either RSmulti or RSS. For both groups, each training session involved 20 repeated 15 s sprints interspersed with 30 s recovery. With RSmulti the COD movements were randomized and performed in response to a visual stimulus, while the RSS involved predefined 180° COD movements. Before and following the six training sessions, performance in the Illinois agility test (IAT), COD speed in response to a visual stimulus, 20 m linear sprint time and vertical jumping height were assessed. Both groups improved their performance in the IAT (p < 0.01, ES = 1.13; p = 0.01, ES = 0.55). The COD speed in response to a visual stimulus improved with the RSmulti (p < 0.01, ES = 1.03), but not the RSS (p = 0.46, ES = 0.28). No differences were found for 20 m sprint time (P=0.73, ES = 0.07; p = 0.14, ES = 0.28) or vertical jumping height (p = 0.46, ES = 0.11; p = 0.29, ES = 0.12) for the RSmulti and RSS, respectively. In conclusion, performance in the IAT improved with the RSmulti as well as RSS. With the RSmulti however, the COD movements are performed in response to a visual stimulus, which may result in specific adaptations that improve COD speed and reactive agility in young highly trained soccer players.}, language = {en} } @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} }