@misc{MuellerEngelMuelleretal.2017,
  author    = {M{\"u}ller, Juliane and Engel, Tilman and M{\"u}ller, Steffen and Stoll, Josefine and Baur, Heiner and Mayer, Frank},
  title     = {Effects of sudden walking perturbations on neuromuscular reflex activity and three-dimensional motion of the trunk in healthy controls and back pain symptomatic subjects},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-394931},
  pages     = {11},
  year      = {2017},
  abstract  = {Background Back pain patients (BPP) show delayed muscle onset, increased co-contractions, and variability as response to quasi-static sudden trunk loading in comparison to healthy controls (H). However, it is unclear whether these results can validly be transferred to suddenly applied walking perturbations, an automated but more functional and complex movement pattern. There is an evident need to develop research-based strategies for the rehabilitation of back pain. Therefore, the investigation of differences in trunk stability between H and BPP in functional movements is of primary interest in order to define suitable intervention regimes. The purpose of this study was to analyse neuromuscular reflex activity as well as three-dimensional trunk kinematics between H and BPP during walking perturbations. Methods Eighty H (31m/49f;29±9yrs;174±10cm;71±13kg) and 14 BPP (6m/8f;30±8yrs;171±10cm;67±14kg) walked (1m/s) on a split-belt treadmill while 15 right-sided perturbations (belt decelerating, 40m/s2, 50ms duration; 200ms after heel contact) were randomly applied. Trunk muscle activity was assessed using a 12-lead EMG set-up. Trunk kinematics were measured using a 3-segment-model consisting of 12 markers (upper thoracic (UTA), lower thoracic (LTA), lumbar area (LA)). EMG-RMS ([\%],0-200ms after perturbation) was calculated and normalized to the RMS of unperturbed gait. Latency (TON;ms) and time to maximum activity (TMAX;ms) were analysed. Total motion amplitude (ROM;[°]) and mean angle (Amean;[°]) for extension-flexion, lateral flexion and rotation were calculated (whole stride cycle; 0-200ms after perturbation) for each of the three segments during unperturbed and perturbed gait. For ROM only, perturbed was normalized to unperturbed step [\%] for the whole stride as well as the 200ms after perturbation. Data were analysed descriptively followed by a student´s t-test to account for group differences. Co-contraction was analyzed between ventral and dorsal muscles (V:R) as well as side right:side left ratio (Sright:Sleft). The coefficient of variation (CV;\%) was calculated (EMG-RMS;ROM) to evaluate variability between the 15 perturbations for all groups. With respect to unequal distribution of participants to groups, an additional matched-group analysis was conducted. Fourteen healthy controls out of group H were sex-, age- and anthropometrically matched (group Hmatched) to the BPP. Results No group differences were observed for EMG-RMS or CV analysis (EMG/ROM) (p>0.025). Co-contraction analysis revealed no differences for V:R and Srigth:Sleft between the groups (p>0.025). BPP showed an increased TON and TMAX, being significant for Mm. rectus abdominus (p = 0.019) and erector spinae T9/L3 (p = 0.005/p = 0.015). ROM analysis over the unperturbed stride cycle revealed no differences between groups (p>0.025). Normalization of perturbed to unperturbed step lead to significant differences for the lumbar segment (LA) in lateral flexion with BPP showing higher normalized ROM compared to Hmatched (p = 0.02). BPP showed a significant higher flexed posture (UTA (p = 0.02); LTA (p = 0.004)) during normal walking (Amean). Trunk posture (Amean) during perturbation showed higher trunk extension values in LTA segments for H/Hmatched compared to BPP (p = 0.003). Matched group (BPP vs. Hmatched) analysis did not show any systematic changes of all results between groups. Conclusion BPP present impaired muscle response times and trunk posture, especially in the sagittal and transversal planes, compared to H. This could indicate reduced trunk stability and higher loading during gait perturbations.},
  language  = {en}
}
@misc{PlummerMugeleSteffenetal.2019,
  author    = {Plummer, Ashley and Mugele, Hendrik and Steffen, Kathrin and Stoll, Josefine and Mayer, Frank and M{\"u}ller, Juliane},
  title     = {General versus sports-specific injury prevention programs in athletes},
  series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  number    = {591},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-44113},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-441131},
  pages     = {17},
  year      = {2019},
  abstract  = {Introduction Injury prevention programs (IPPs) are an inherent part of training in recreational and professional sports. Providing performance-enhancing benefits in addition to injury prevention may help adjust coaches and athletes' attitudes towards implementation of injury prevention into daily routine. Conventional thinking by players and coaches alike seems to suggest that IPPs need to be specific to one's sport to allow for performance enhancement. The systematic literature review aims to firstly determine the IPPs nature of exercises and whether they are specific to the sport or based on general conditioning. Secondly, can they demonstrate whether general, sports-specific or even mixed IPPs improve key performance indicators with the aim to better facilitate long-term implementation of these programs? Methods PubMed and Web of Science were electronically searched throughout March 2018. The inclusion criteria were randomized control trials, publication dates between Jan 2006 and Feb 2018, athletes (11-45 years), injury prevention programs and included predefined performance measures that could be categorized into balance, power, strength, speed/agility and endurance. The methodological quality of included articles was assessed with the Cochrane Collaboration assessment tools. Results Of 6619 initial findings, 22 studies met the inclusion criteria. In addition, reference lists unearthed a further 6 studies, making a total of 28. Nine studies used sports specific IPPs, eleven general and eight mixed prevention strategies. Overall, general programs ranged from 29-57\% in their effectiveness across performance outcomes. Mixed IPPs improved in 80\% balance outcomes but only 20-44\% in others. Sports-specific programs led to larger scale improvements in balance (66\%), power (83\%), strength (75\%), and speed/agility (62\%). Conclusion Sports-specific IPPs have the strongest influence on most performance indices based on the significant improvement versus control groups. Other factors such as intensity, technical execution and compliance should be accounted for in future investigations in addition to exercise modality.},
  language  = {en}
}
@misc{MugelePlummerSteffenetal.2018,
  author    = {Mugele, Hendrik and Plummer, Ashley and Steffen, Kathrin and Stoll, Josefine and Mayer, Frank and M{\"u}ller, Juliane},
  title     = {General versus sports-specific injury prevention programs in athletes},
  series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  number    = {481},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-419935},
  pages     = {16},
  year      = {2018},
  abstract  = {Introduction Annually, 2 million sports-related injuries are reported in Germany of which athletes contribute to a large proportion. Multiple sport injury prevention programs designed to decrease acute and overuse injuries in athletes have been proven effective. Yet, the programs' components, general or sports-specific, that led to these positive effects are uncertain. Despite not knowing about the superiority of sports-specific injury prevention programs, coaches and athletes alike prefer more specialized rather than generalized exercise programs. Therefore, this systematic review aimed to present the available evidence on how general and sports-specific prevention programs affect injury rates in athletes. Methods PubMed and Web of Science were electronically searched throughout April 2018. The inclusion criteria were publication dates Jan 2006-Dec 2017, athletes (11-45 years), exercise-based injury prevention programs and injury incidence. The methodological quality was assessed with the Cochrane Collaboration assessment tools. Results Of the initial 6619 findings, 15 studies met the inclusion criteria. In addition, 13 studies were added from reference lists and external sources making a total of 28 studies. Of which, one used sports-specific, seven general and 20 mixed prevention strategies. Twenty-four studies revealed reduced injury rates. Of the four ineffective programs, one was general and three mixed. Conclusion The general and mixed programs positively affect injury rates. Sports-specific programs are uninvestigated and despite wide discussion regarding the definition, no consensus was reached. Defining such terminology and investigating the true effectiveness of such IPPs is a potential avenue for future research.},
  language  = {en}
}
@misc{MuellerMuellerStolletal.2017,
  author    = {M{\"u}ller, Steffen and M{\"u}ller, Juliane and Stoll, Josefine and Prieske, Olaf and Cassel, Michael and Mayer, Frank},
  title     = {Incidence of back pain in adolescent athletes},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-101874},
  pages     = {5},
  year      = {2017},
  abstract  = {Background Recently, the incidence rate of back pain (BP) in adolescents has been reported at 21\%. However, the development of BP in adolescent athletes is unclear. Hence, the purpose of this study was to examine the incidence of BP in young elite athletes in relation to gender and type of sport practiced. Methods Subjective BP was assessed in 321 elite adolescent athletes (m/f 57\%/43\%; 13.2 ± 1.4 years; 163.4 ± 11.4 cm; 52.6 ± 12.6 kg; 5.0 ± 2.6 training yrs; 7.6 ± 5.3 training h/week). Initially, all athletes were free of pain. The main outcome criterion was the incidence of back pain [\%] analyzed in terms of pain development from the first measurement day (M1) to the second measurement day (M2) after 2.0 ± 1.0 year. Participants were classified into athletes who developed back pain (BPD) and athletes who did not develop back pain (nBPD). BP (acute or within the last 7 days) was assessed with a 5-step face scale (face 1-2 = no pain; face 3-5 = pain). BPD included all athletes who reported faces 1 and 2 at M1 and faces 3 to 5 at M2. nBPD were all athletes who reported face 1 or 2 at both M1 and M2. Data was analyzed descriptively. Additionally, a Chi2 test was used to analyze gender- and sport-specific differences (p = 0.05). Results Thirty-two athletes were categorized as BPD (10\%). The gender difference was 5\% (m/f: 12\%/7\%) but did not show statistical significance (p = 0.15). The incidence of BP ranged between 6 and 15\% for the different sport categories. Game sports (15\%) showed the highest, and explosive strength sports (6\%) the lowest incidence. Anthropometrics or training characteristics did not significantly influence BPD (p = 0.14 gender to p = 0.90 sports; r2 = 0.0825). Conclusions BP incidence was lower in adolescent athletes compared to young non-athletes and even to the general adult population. Consequently, it can be concluded that high-performance sports do not lead to an additional increase in back pain incidence during early adolescence. Nevertheless, back pain prevention programs should be implemented into daily training routines for sport categories identified as showing high incidence rates.},
  language  = {en}
}
@misc{MuellerCarlsohnMuelleretal.2016,
  author    = {M{\"u}ller, Steffen and Carlsohn, Anja and M{\"u}ller, Juliane and Baur, Heiner and Mayer, Frank},
  title     = {Influence of Obesity on Foot Loading Characteristics in Gait for Children Aged 1 to 12 Years},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-90108},
  year      = {2016},
  abstract  = {Background Overweight and obesity are increasing health problems that are not restricted to adults only. Childhood obesity is associated with metabolic, psychological and musculoskeletal comorbidities. However, knowledge about the effect of obesity on the foot function across maturation is lacking. Decreased foot function with disproportional loading characteristics is expected for obese children. The aim of this study was to examine foot loading characteristics during gait of normal-weight, overweight and obese children aged 1-12 years. Methods A total of 10382 children aged one to twelve years were enrolled in the study. Finally, 7575 children (m/f: n = 3630/3945; 7.0 +/- 2.9yr; 1.23 +/- 0.19m; 26.6 +/- 10.6kg; BMI: 17.1 +/- 2.4kg/m(2)) were included for (complete case) data analysis. Children were categorized to normalweight (>= 3rd and <90th percentile; n = 6458), overweight (>= 90rd and <97th percentile; n = 746) or obese (>97th percentile; n = 371) according to the German reference system that is based on age and gender-specific body mass indices (BMI). Plantar pressure measurements were assessed during gait on an instrumented walkway. Contact area, arch index (AI), peak pressure (PP) and force time integral (FTI) were calculated for the total, fore-, mid-and hindfoot. Data was analyzed descriptively (mean +/- SD) followed by ANOVA/Welch-test (according to homogeneity of variances: yes/no) for group differences according to BMI categorization (normal-weight, overweight, obesity) and for each age group 1 to 12yrs (post-hoc Tukey Kramer/Dunnett's C; alpha = 0.05). Results Mean walking velocity was 0.95 +/- 0.25 m/s with no differences between normal-weight, overweight or obese children (p = 0.0841). Results show higher foot contact area, arch index, peak pressure and force time integral in overweight and obese children (p< 0.001). Obese children showed the 1.48-fold (1 year-old) to 3.49-fold (10 year-old) midfoot loading (FTI) compared to normal-weight. Conclusion Additional body mass leads to higher overall load, with disproportional impact on the midfoot area and longitudinal foot arch showing characteristic foot loading patterns. Already the feet of one and two year old children are significantly affected. Childhood overweight and obesity is not compensated by the musculoskeletal system. To avoid excessive foot loading with potential risk of discomfort or pain in childhood, prevention strategies should be developed and validated for children with a high body mass index and functional changes in the midfoot area. The presented plantar pressure values could additionally serve as reference data to identify suspicious foot loading patterns in children.},
  language  = {en}
}
@misc{CasselMuellerMoseretal.2019,
  author    = {Cassel, Michael and M{\"u}ller, Juliane and Moser, Othmar and Strempler, Mares Elaine and Reso, Judith and Mayer, Frank},
  title     = {Orthopedic Injury Profiles in Adolescent Elite Athletes},
  series = {Postprints der Universit{\"a}t Potsdam Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam Humanwissenschaftliche Reihe},
  number    = {559},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-43495},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-434953},
  pages     = {10},
  year      = {2019},
  abstract  = {Aim: The aim of the study was to identify common orthopedic sports injury profiles in adolescent elite athletes with respect to age, sex, and anthropometrics. Methods: A retrospective data analysis of 718 orthopedic presentations among 381 adolescent elite athletes from 16 different sports to a sports medical department was performed. Recorded data of history and clinical examination included area, cause and structure of acute and overuse injuries. Injury-events were analyzed in the whole cohort and stratified by age (11-14/15-17 years) and sex. Group differences were tested by chi-squared-tests. Logistic regression analysis was applied examining the influence of factors age, sex, and body mass index (BMI) on the outcome variables area and structure (a = 0.05). Results: Higher proportions of injury-events were reported for females (60\%) and athletes of the older age group (66\%) than males and younger athletes. The most frequently injured area was the lower extremity (47\%) followed by the spine (30.5\%) and the upper extremity (12.5\%). Acute injuries were mainly located at the lower extremity (74.5\%), while overuse injuries were predominantly observed at the lower extremity (41\%) as well as the spine (36.5\%). Joints (34\%), muscles (22\%), and tendons (21.5\%) were found to be the most often affected structures. The injured structures were different between the age groups (p = 0.022), with the older age group presenting three times more frequent with ligament pathology events (5.5\%/2\%) and less frequent with bony problems (11\%/20.5\%) than athletes of the younger age group. The injured area differed between the sexes (p = 0.005), with males having fewer spine injury-events (25.5\%/34\%) but more upper extremity injuries (18\%/9\%) than females. Regression analysis showed statistically significant influence for BMI (p = 0.002) and age (p = 0.015) on structure, whereas the area was significantly influenced by sex (p = 0.005). Conclusion: Events of soft-tissue overuse injuries are the most common reasons resulting in orthopedic presentations of adolescent elite athletes. Mostly, the lower extremity and the spine are affected, while sex and age characteristics on affected area and structure must be considered. Therefore, prevention strategies addressing the injury-event profiles should already be implemented in early adolescence taking age, sex as well as injury entity into account.},
  language  = {en}
}