TY - JOUR A1 - Burkart, Michael A1 - Alsleben, Katja A1 - Lachmuth, Susanne A1 - Schumacher, Juliane A1 - Hofmann, Ralf A1 - Jeltsch, Florian A1 - Schurr, Frank Martin T1 - Recruitment requirements of the rare and threatened Juncus atratus N2 - The long-term persistence of populations and species depends on the successful recruitment of individuals. The generative recruitment of plants may be limited by a lack of suitable germination and establishment conditions. Establishment limitation may especially be caused by the competitive effect of surrounding dense vegetation, which is believed to restrict the recruitment success of many plant species to small open patches ('safe sites'). We conducted experiments to clarify the roles of germination and seedling establishment as limiting processes in the recruitment of Juncus atratus Krock., a rare and threatened herbaceous perennial river corridor plant in Central Europe. Light intensity had a positive effect on germination. However, some seedlings emerged even in total darkness and the germination rate at 1% light intensity was more than half of that at 60% light intensity. Seedling establishment in the field after 10 weeks was 30% on bare ground, but it was close to zero in grassland. Establishment in the growth chamber after 8 weeks was close to 75% for seedlings that germinated underwater, but only about 35% for seedlings that germinated afloat. Furthermore, establishment decreased with flooding duration on bare ground, but increased with flooding duration in grassland. These data indicate that establishment, rather than germination, is a critical life stage in Central European populations off. atratus. They furthermore indicate that the competition of surrounding vegetation for water limits seedling establishment under field conditions without flooding, largely restricting establishment success to bare ground habitats. In contrast, grassland is more suitable for the recruitment off. atratus than bare ground under prolonged flooding. Grassland may facilitate the establishment off. atratus seedlings during long- lasting floods by supplying oxygen to the soil through aerenchyma. The shift from competition to facilitation in grassland occurred after 30 days of flooding, i.e. within the ontogeny of individual plants. The specific recruitment requirements off. arrows may be a main cause of its rarity in modern Central Europe. In order to prevent regional extinction off. atratus, we suggest maintaining or re-establishing natural hydrodynamics in the species' habitats. Y1 - 2010 UR - http://www.sciencedirect.com/science/journal/03672530 U6 - https://doi.org/10.1016/j.flora.2009.08.003 SN - 0367-2530 ER - TY - CHAP A1 - Cassel, Michael A1 - Carlsohn, Anja A1 - Froehlich, Katja A1 - Mayer, Frank T1 - Achilles tendinopathy in adolescent athletes using ultrasound and clinical examination T2 - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine Y1 - 2013 SN - 0195-9131 SN - 1530-0315 VL - 45 IS - 5 SP - 350 EP - 350 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - CHAP A1 - Wochatz, Monique A1 - Cassel, Michael A1 - König, Niklas A1 - Fröhlich, Katja A1 - Mayer, Frank T1 - Intra- and inter-observer variability of a retrospective analysis of achilles tendon ultrasound scans T2 - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine Y1 - 2013 SN - 0195-9131 SN - 1530-0315 VL - 45 IS - 5 SP - 239 EP - 239 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - JOUR A1 - Cassel, Michael A1 - Carlsohn, Anja A1 - Fröhlich, Katja A1 - John, Mareike A1 - Riegels, N. A1 - Mayer, Frank T1 - Tendon Adaptation to Sport-specific Loading in Adolescent Athletes JF - International journal of sports medicine N2 - Tendon adaptation due to mechanical loading is controversially discussed. However, data concerning the development of tendon thickness in adolescent athletes is sparse. The purpose of this study was to examine possible differences in Achilles (AT) and patellar tendon (PT) thickness in adolescent athletes while considering age, gender and sport-specific loading. In 500 adolescent competitive athletes of 16 different sports and 40 recreational controls both ATs and PTs were sonographically measured. Subjects were divided into 2 age groups (< 13; ≥ 13 years) and 6 sport type categories (ball, combat, and water sports, combined disciplines, cycling, controls). In addition, 3 risk groups (low, moderate, high) were created according to the athlete’s risk of developing tendinopathy. AT and PT thickness did not significantly differ between age groups (AT/PT:<13: 5.4±0.7 mm/3.6±0.5 mm;≥13: 5.3±0.7 mm/3.6±0.5 mm). In both age groups males presented higher tendon thickness than females (p<0.001). AT thickness was highest in ball sports/cyclists and lowest in controls (p≤0.002). PT thickness was greatest in water sports and lowest in controls (p=0.02). High risk athletes presented slightly higher AT thickness compared to the low risk group (p=0.03). Increased AT and PT thickness in certain sport types compared to controls supports the hypothesis of structural tendon adaptation due to sport-specific loading. KW - achilles and patellar tendon KW - training adaptation KW - tendon thickness KW - standard values KW - sonography Y1 - 2016 U6 - https://doi.org/10.1055/s-0035-1559772 SN - 0172-4622 SN - 1439-3964 VL - 37 SP - 159 EP - 164 PB - Thieme CY - Stuttgart ER - TY - CHAP A1 - Intziegianni, Konstantina A1 - Cassel, Michael A1 - Hain, Gerrit A1 - Fröhlic, Katja A1 - Mayer, Frank T1 - Reliability of sonographic assessment of Achilles tendon cross-sectional area at rest and maximal voluntary contraction T2 - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine Y1 - 2014 SN - 0195-9131 SN - 1530-0315 VL - 46 IS - 5 SP - 47 EP - 47 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - JOUR A1 - Cassel, Michael A1 - Baur, Heiner A1 - Hirschmueller, Anja A1 - Carlsohn, Anja A1 - Fröhlich, Katja A1 - Mayer, Frank T1 - Prevalence of Achilles and patellar tendinopathy and their association to intratendinous changes in adolescent athletes JF - Scandinavian journal of medicine & science in sports N2 - Achilles (AT) and patellar tendons (PT) are commonly affected by tendinopathy in adult athletes but prevalence of symptoms and morphological changes in adolescents is unclear. The study aimed to determine prevalence of tendinopathy and intratendinous changes in ATs and PTs of adolescent athletes. A total of 760 adolescent athletes (13.0 +/- 1.9 years; 160 +/- 13cm; 50 +/- 14kg) were examined. History, local clinical examination, and longitudinal Doppler ultrasound analysis for both ATs and PTs were performed including identification of intratendinous echoic changes and vascularization. Diagnosis of tendinopathy was complied clinically in case of positive history of tendon pain and tendon pain on palpation. Achilles tendinopathy was diagnosed in 1.8% and patellar tendinopathy in 5.8%. Vascularizations were visible in 3.0% of ATs and 11.4% of PTs, hypoechogenicities in 0.7% and 3.2% as well as hyperechogenicities in 0% and 0.3%, respectively. Vascularizations and hypoechogenicities were statistically significantly more often in males than in females (P0.02). Subjects with patellar tendinopathy had higher prevalence of structural intratendinous changes than those without PT symptoms (P0.001). In adolescent athletes, patellar tendinopathy is three times more frequent compared with Achilles tendinopathy. Longitudinal studies are necessary to investigate physiological or pathological origin of vascularizations and its predictive value in development of tendinopathy. KW - Prevalence KW - tendinopathy KW - sonography KW - Doppler ultrasound KW - vascularization KW - hypoechogenicities KW - hyperechogenicities KW - adolescent athletes Y1 - 2015 U6 - https://doi.org/10.1111/sms.12318 SN - 0905-7188 SN - 1600-0838 VL - 25 IS - 3 SP - e310 EP - e318 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Intziegianni, Konstantina A1 - Cassel, Michael A1 - König, Niklas A1 - Müller, Steffen A1 - Fröhlich, Katja A1 - Mayer, Frank T1 - Ultrasonography for the assessment of the structural properties of the Achilles tendon in asymptomatic individuals: An intra-rater reproducibility study JF - Isokinetics and exercise science : official journal of the European Isokinetic Society N2 - BACKGROUND: Reproducible measurements of tendon structural properties are a prerequisite for accurate diagnosis of tendon disorders and for determination of their mechanical properties. Despite the widely used application of Ultrasonography (US) in musculoskeletal assessment, its operator dependency and lack of standardization influences the consistency of the measurement. OBJECTIVE: To evaluate the intra-rater reproducibility of a standardized US method assessing the structural properties of the Achilles tendon (AT). METHODS: Sixteen asymptomatic participants were positioned prone on an isokinetic dynamometer with the knee extended and ankle at 90. flexion. US was used to assess AT-length, cross-sectional area (CSA), and AT-elongation during isometric plantarflexion contraction. The intra-rater reproducibility was assessed by ICC (2.1), Test-Retest Variability (TRV, %), Bland-Altman analyses (Bias +/- LoA [1.96*SD]), and Standard-Error of Measurement (SEM). RESULTS: Measurements of AT-length demonstrated an ICC of 0.93, TRV of 4.5 +/- 3.9%, Bias +/- LoA of -2.8 +/- 25.0 mm and SEM of 6.6 mm. AT-CSA showed an ICC of 0.79, TRV of 8.7 +/- 9.6%, Bias +/- LoA of 1.7 +/- 19.4 mm(2) and SEM of 5.3 mm(2). AT-elongation revealed an ICC of 0.92, TRV of 12.9 +/- 8.9%, Bias +/- LoA of 0.3 +/- 5.7 mm and SEM of 1.5 mm. CONCLUSIONS: The presented methodology allows a reproducible assessment of Achilles tendon structural properties when performed by a single rater. KW - Ultrasonography KW - Achilles tendon KW - reproducibility KW - isokinetic Y1 - 2015 U6 - https://doi.org/10.3233/IES-150586 SN - 0959-3020 SN - 1878-5913 VL - 23 IS - 4 SP - 263 EP - 270 PB - IOS Press CY - Amsterdam ER - TY - JOUR A1 - Kopinski, Stephan A1 - Engel, Tilman A1 - Cassel, Michael A1 - Fröhlich, Katja A1 - Mayer, Frank A1 - Carlsohn, Anja T1 - Ultrasound Applied to Subcutaneous Fat Tissue Measurements in International Elite Canoeists JF - International journal of sports medicine N2 - Subcutaneous adipose tissue (SAT) measurements with ultrasound have recently been introduced to assess body fat in elite athletes. However, appropriate protocols and data on various groups of athletes are missing. We investigated intra-rater reliability of SAT measurements using ultrasound in elite canoe athletes. 25 international level canoeists (18 male, 7 female; 23 +/- 4 years; 81 +/- 11 kg; 1.83 +/- 0.09 m; 20 +/- 3 training h/wk) were measured on 2 consecutive days. SAT was assessed with B-mode ultrasound at 8 sites (ISAK): triceps, subscapular, biceps, iliac crest, supraspinal, abdominal, front thigh, medial calf, and quantified using image analysis software. Data was analyzed descriptively (mean +/- SD, [range]). Coefficient of variation (CV %), intraclass correlation coefficient (ICC, 2.1) and absolute (LoA) and ratio limits of agreement (RLoA) were calculated for day-to-day reliability. Mean sum of SAT thickness was 30.0 +/- 19.4 mm [8.0, 80.1 mm], with 3.9 +/- 1.8 mm [1.2 mm subscapular, 8.0 mm abdominal] for individual sites. CV for the sum of sites was 4.7 %, ICC 0.99, LoA 1.7 +/- 3.6 mm, RLoA 0.940 (*/divided by 1.155). Measuring SAT with ultrasound has proved to have excellent day-to-day reliability in elite canoe athletes. Recommendations for standardization of the method will further increase accuracy and reproducibility. KW - subcutaneous adipose tissue KW - skinfold thickness KW - elite athletes KW - body composition KW - ultrasonography Y1 - 2015 U6 - https://doi.org/10.1055/s-0035-1555857 SN - 0172-4622 SN - 1439-3964 VL - 36 IS - 14 SP - 1134 EP - 1141 PB - Thieme CY - Stuttgart ER -