Christian Klein

The Greenland-Norwegian Seaway: a key area for understanding Late Jurassic to early Cretaceous paleoenvironments

The paleoclimatology and paleoceanology of the Late Jurassic and Early Cretaceous are of special interest because this was a time when large amounts of marine organic matter were deposited in sediments that have subsequently become petroleum source rocks. However, because of the lack of outcrops, most studies have concentrated on low latitudes, in particular the Tethys and the “Boreal Realm,” where information has been based largely on material from northwest Germany, the North Sea, and England. These areas were all south of 40°N latitude during the Late Jurassic and Early Cretaceous. We have studied sediment samples of Kimmeridgian (∼154 Ma) to Barremian (∼121 Ma) age from cores taken at sites offshore mid-Norway and in the Barents Sea that lay in a narrow seaway connecting the Tethys with the northern polar ocean. During the Late Jurassic-Early Cretaceous these sites had paleolatitudes of 42–67°N. The Late Jurassic-Early Cretaceous sequences at these sites reflect the global sea-level rise during the Volgian-Hauterivian and a climatic shift from warm humid conditions in Volgian times to arid cold climates in the early Hauterivian. The sediments indicate orbital control of climate, reflected in fluctuations in the clastic influx and variations in carbonate and organic matter production. Trace element concentrations in the Volgian-Berriasian sediments suggest that the central part of the Greenland-Norwegian Seaway might have had suboxic bottom water beneath an oxic water column. Both marine and terrigenous organic matter are present in the seaway sediments. The Volgian-Berriasian strata have unusually high contents of organic carbon and are the source rocks for petroleum and gas fields in the region. The accumulation of organic carbon is attributed to restricted conditions in the seaway during this time of low sea level. It might be that the Greenland-Norwegian segment was the deepest part of the transcontinental seaway, bounded at both ends by relatively shallow swells. The decline in organic matter content of the sediments in the Valanginian-Hauterivian indicates greater ventilation and more active flow through the seaway as the sea level rose. The same benthic foraminifera assemblages are encountered throughout the seaway. Endemic assemblages of arenaceous foraminifera in the Volgian-Berriasian give way to more diverse and cosmopolitan Valanginian-Hauterivian benthic communities that include calcareous species. The foraminiferal assemblages also suggest low oxygen content bottom waters during the earlier Cretaceous, changing to more fully oxygenated conditions later. The calcareous nannoplankton, particularly Crucibiscutum salebrosum, which is rare at low latitudes and abundant in high latitudes, reflect the meridional thermal gradient. They indicate that the Greenland-Norwegian segment of the seaway was north of a subtropical frontal zone that acted as a barrier between the Tethyan and Boreal Realms. This implies the existence of stable climatic belts during the early Valanginian and Hauterivian, significant meridional temperature gradients, and moderate “ice house” conditions.

Benthic foraminifera: indicators for a long-term improvement of living conditions in the Late Valanginian of the NW German Basin

Foraminiferal occurrences in marine sediments of Late Valanginian age (Early Cretaceous) are described from NW Germany. The distribution patterns of benthic foraminifera are discussed with respect to their abundance and diversity. Benthic foraminifera are characterized in terms of moderate diversity and abundance. Vertical fluctuations in foraminifera contents are discussed with respect to their palaeoecology and palaeobiogeography. Benthic foraminifera, which are represented by a total of 101 species, show a gradual increase of diversity throughout the Late Valanginian. This improvement of living conditions in an epicontinental sea over a period of approximately 2 million years indicates a gradual recolonization of the formerly non-marine semi-restricted basin. The associations are dominated by agglutinated taxa with common Ammobaculites, Ammovertella, Bulbobaculites, Haplophragmoides, Proteonina, Psammosphaera and Reophax. The calcareous species Epistomina caracolla, which is extremely common in certain intervals, may reach significant abundances. Further agglutinated and calcareous taxa occur rarely. The early Late Valanginian is marked by the occurrence of the Tethyan species Cerobertinella subhercynica, reflecting a major sea-level highstand.

Development and Implementation of a Modular Return-to-Play Test Battery After ACL Reconstruction

Several studies in football have demonstrated a significant reduction of injuries through various preventive measures. However, even under ideal conditions, injuries will occur in contact team sports like football. As injuries are expected to be part of the game, there is a certain need to develop proper concepts for secondary and tertiary prevention. In this context the return-to-play decision is a decisive aspect, in particular with regard to frequently reoccurring as well as severe injuries like ACL tears. Rather than time, which is an important factor in biological healing, objective parameters are needed to monitor, control, and optimize the rehabilitation process. Especially when it comes to the final return-to-play decision after an ACL injury, it is advisable to carry out a comprehensive test battery that considers clinical, physiological, and psychological aspects. Moreover, this testing should anticipate the specificity of the sport the injured athlete is returning to. With regard to the right timing of the comeback, individual baseline values from pre-injury screenings are superior to the frequently used limb symmetry index (LSI) or data from reference populations. Particularly in football where lower limb asymmetries due to leg dominances have to be taken into consideration when interpreting test results, solely usage of the LSI seems to be questionable. In the light of the ambitions to develop a standardized test battery, the Verwaltungs-Berufsgenossenschaft (VBG), the statutory accident insurance for German professional sports, conducted a consensus conference bringing together accredited experts and working groups from all professions that are typically involved in the rehabilitation process. As a result of this conference, a modular test battery was introduced for multicentric test implementation in real-world sports settings.

INJURIES IN MEN'S PROFESSIONAL FOOTBALL

Background The first step on the way to developing preventive measures is the description of epidemiology within the target group. This is not known for German Mens Professional Football so far. Objective Analysis of injury risk and description of injury patterns. Design Prospective observational cohort study of the season 2014–15. Setting Two highest leagues in German mens football (i.e. Bundesliga, 2. Bundesliga). Patients (or Participants) All first and second division football players who played at least one competitive club match (n=1,358) during the 2014–15 season were included. Interventions (or Assessment of Risk Factors) Analysis of all injuries of the participants that were registered by clubs or physicians with the VBG as part of the occupational accident reporting and that either led to the players short-term disability (time-loss) or to medical treatment costs (medical-attention). Main Outcome Measurements Prevalence rate and injury incidence, injured body regions, type of injury, medical costs and time loss. Results 1,076 of the 1,358 players (79.2%) were injured. A total of 3,385 injuries were recorded (training: 62.3%, match: 37.3%) which led to a cumulative incidence rate of 2.5 injuries per player and season. Goalkeeper had lower overall risk of injury (2.1 inj./season), but a 3.7 times higher relative risk of concussions than field players. 70.7% of all injuries were lower extremity injuries. Thigh injuries (21.3%) and knee injuries (15.8%) were the most frequent injuries. However, knee injuries caused 37.0% of overall time-loss and 48.4% of overall medical-attention. Conclusions German mens professional football shows a high risk of injury. Injury risk and injury patterns differ by playing position, probably reflecting the specific performance profiles of the respective playing position. Thus prevention needs to be individualised and at least must consider different characteristics of playing positions. For development of expedient preventive measures, injury mechanisms need to be analysed.

INJURIES IN GERMAN MEŃS PROFESSIONAL ICE HOCKEY

Background Injury incidences during international major ice hockey events are high, but information about ice hockey injuries in Germany, particularly in regular league play, is lacking. Objective Analysis of injury characteristics in German professional ice hockey. Design Prospective observational cohort study. Setting Two highest German professional leagues in mens ice hockey. Participants All first and second division ice hockey players who played at least in one competitive club match during the season 2014/15 season (n=812). Assessment of Risk Factors Analysis of all injuries of these players that were registered by clubs or physicians with the VBG as a part of the occupational accident reporting and that either led to the players short-term disability (time-loss) and/or to medical treatment costs (medical-attention). Main Outcome Measurements Injury prevalence and incidence, injured body parts, type of injury, medical treatment costs, days of absence. Results A total of 2.045 injuries were recorded. 76.7% of all players were injured at least once. In mean each player had 2.52 injuries per season. Incidence rate in the first division (2.7 injuries/season) was significantly higher than in second division (2.3 injuries/season). The majority of injuries (69.1%) occurred during matches with a match incidence of 136.8 injuries per 1000 h. Nearly one third (30.7%) of all training injuries occurred during the pre-season. The head (17.9%), the shoulder (10.7%) and the thigh (10.1%) were the body parts most frequently affected. Shoulder injuries lead to the highest share of overall time-loss (20.5%) and medical treatment costs (22.0%). Goalkeeper had significant lower overall risk of injury (1.5 injuries/season), but higher risk of knee and thigh injuries. Conclusions Injury Risk in German professional ice hockey is high, especially during match play. Preventive measures should aim at sport- and position-specific risk factors. Special focus should be laid on player preparedness after off-season break.

INJURY PATTERNS IN GERMAN MEN'S PROFESSIONAL BASKETBALL AND HANDBALL – A COMPARISON

Background Basketball (BB) and handball (HB) are both dynamic and physical indoor transition team sports. However, performance profiles, specifically with regard to allowed legal physical contact, differ widely. Knowledge of injury risk and injury patterns, particularly in regular league play, is limited. Objective Comparative analysis of injury risk and injury patterns in German mens professional BB and HB. Design Prospective observational cohort study. Setting Two highest German professional leagues in mens BB and HB. Participants All first and second league BB (n=514) and HB (n=804) players who played in at least one competitive club match during the 2014–2015 season. Interventions (or Assessment of Risk Factors) Analysis of all injuries that were registered by clubs or physicians with the VBG as part of the occupational accident reporting and that either led to players short-term disability (time-loss) and/or to medical treatment costs (medical-attention). Main Outcome Measurements Injury prevalence, injury incidence, injured body parts, type of injury, medical costs, short-term disability. Results 992 of the 1.318 observed players were injured. A total of 3,071 injuries were recorded. Prevalence rate (BB: 70.0%; HB: 78.6%) and cumulative incidence rate (BB: 2.0 injuries/season; HB: 2.5 injuries/season) were significantly higher in HB. By contrast, BB (95.4 injuries/1,000 h) showed higher match incidences than HB (74.7 injuries/1,000 h). The ankle (19.6%) in BB and the knee (15.2%) in HB were the body parts most commonly affected. Moreover, in both sports injury risk and patterns varied considerably according to level of play (league) and playing position. Conclusions Both, German mens professional BB and HB are associated with a high risk of injury in regular league play. However, injury patterns in professional mens BB and HB differ extensively reflecting varying performance profiles. Preventive strategies and measures should therefore be tailored towards sport-specific and, moreover, position-specific risks and patterns.