@article{MuellerHadzicMugeleetal.2017,
  author    = {M{\"u}ller, Juliane and Hadzic, Miralem and Mugele, Hendrik and Stoll, Josefine and M{\"u}ller, Steffen and Mayer, Frank},
  title     = {Effect of high-intensity perturbations during core-specific sensorimotor exercises on trunk muscle activation},
  series = {Journal of biomechanics},
  volume    = {70},
  journal   = {Journal of biomechanics},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0021-9290},
  doi       = {10.1016/j.jbiomech.2017.12.013},
  pages     = {212 -- 218},
  year      = {2017},
  abstract  = {Core-specific sensorimotor exercises are proven to enhance neuromuscular activity of the trunk. However, the influence of high-intensity perturbations on training efficiency is unclear within this context. Sixteen participants (29 +/- 2 yrs; 175 +/- 8 cm; 69 +/- 13 kg) were prepared with a 12-lead bilateral trunk EMG. Warm-up on a dynamometer was followed by maximum voluntary isometric trunk (flex/ext) contraction (MVC). Next, participants performed four conditions for a one-legged stance with hip abduction on a stable surface (HA) repeated randomly on an unstable surface (HAP), on a stable surface with perturbation (HA + P), and on an unstable surface with perturbation (HAP + P). Afterwards, bird dog (BD) was performed under the same conditions (BD, BDP, BD + P, BDP + P). A foam pad under the foot (HA) or the knee (BD) was used as an unstable surface. Exercises were conducted on a moveable platform. Perturbations (ACC 50 m/sec(2);100 ms duration;10rep.) were randomly applied in the anterior-posterior direction. The root mean square (RMS) normalized to MVC (\%) was calculated (whole movement cycle). Muscles were grouped into ventral right and left (VR;VL), and dorsal right and left (DR;DL). Ventral Dorsal and right-left ratios were calculated (two way repeated-measures ANOVA;alpha = 0,05). Amplitudes of all muscle groups in bird dog were higher compared to hip abduction (p <= 0.0001; Range: BD: 14 +/- 3\% (BD;VR) to 53 +/- 4\%; HA: 7 +/- 2\% (HA;DR) to 16 +/- 4\% (HA;DR)). EMG-RMS showed significant differences (p < 0.001) between conditions and muscle groups per exercise. Interaction effects were only significant for HA (p = 0.02). No significant differences were present in EMG ratios (p > 0.05). Additional high-intensity perturbations during core-specific sensorimotor exercises lead to increased neuromuscular activity and therefore higher exercise intensities. However, the beneficial effects on trunk function remain unclear. Nevertheless, BD is more suitable to address trunk muscles.},
  language  = {en}
}
@article{MuellerStollMuelleretal.2018,
  author    = {M{\"u}ller, Juliane and Stoll, Josefine and Mueller, Steffen and Mayer, Frank},
  title     = {Dose-response relationship of core-specific sensorimotor interventions in healthy, well-trained participants},
  series = {Trials},
  volume    = {19},
  journal   = {Trials},
  publisher = {BMC},
  address   = {London},
  issn      = {1745-6215},
  doi       = {10.1186/s13063-018-2799-9},
  pages     = {8},
  year      = {2018},
  abstract  = {Background: Core-specific sensorimotor exercises are proven to enhance neuromuscular activity of the trunk, improve athletic performance and prevent back pain. However, the dose-response relationship and, therefore, the dose required to improve trunk function is still under debate. The purpose of the present trial will be to compare four different intervention strategies of sensorimotor exercises that will result in improved trunk function. Discussion: The results of the study will be clinically relevant, not only for researchers but also for (sports) therapists, physicians, coaches, athletes and the general population who have the aim of improving trunk function.},
  language  = {en}
}
@article{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 = {PLOS ONE},
  volume    = {13},
  journal   = {PLOS ONE},
  number    = {10},
  publisher = {Public Library of Science},
  address   = {San Francisco},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0205635},
  pages     = {1 -- 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}
}
@article{MuellerMartinezValdesStolletal.2018,
  author    = {Mueller, Juliane and Martinez-Valdes, Eduardo Andr{\´e}s and Stoll, Josefine and Mueller, Steffen and Engel, Tilman and Mayer, Frank},
  title     = {Differences in neuromuscular activity of ankle stabilizing muscles during postural disturbances},
  series = {Gait \& posture},
  volume    = {61},
  journal   = {Gait \& posture},
  publisher = {Elsevier},
  address   = {Clare},
  issn      = {0966-6362},
  doi       = {10.1016/j.gaitpost.2018.01.023},
  pages     = {226 -- 231},
  year      = {2018},
  abstract  = {The purpose was to examine gender differences in ankle stabilizing muscle activation during postural disturbances. Seventeen participants (9 females: 27 +/- 2yrs., 1.69 +/- 0.1 m, 63 +/- 7 kg; 8 males: 29 +/- 2yrs., 1.81 +/- 0.1 m; 83 +/- 7 kg) were included in the study. After familiarization on a split-belt-treadmill, participants walked (1 m/s) while 15 right-sided perturbations were randomly applied 200 ms after initial heel contact. Muscle activity of M. tibialis anterior (TA), peroneus longus (PL) and gastrocnemius medialis (GM) was recorded during unperturbed and perturbed walking. The root mean square (RMS; [\%]) was analyzed within 200 ms after perturbation. Co-activation was quantified as ratio of antagonist (GM)/agonist (TA) EMG-RMS during unperturbed and perturbed walking. Time to onset was calculated (ms). Data were analyzed descriptively (mean +/- SD) followed by three-way-ANOVA (gender/condition/muscle; alpha= 0.05). Perturbed walking elicited higher EMG activity compared to normal walking for TA and PL in both genders (p < 0.000). RMS amplitude gender comparisons revealed an interaction between gender and condition (F = 4.6, p = 0.049) and, a triple interaction among gender, condition and muscle (F = 4.7, p = 0.02). Women presented significantly higher EMG-RMS [\%] PL amplitude than men during perturbed walking (mean difference = 209.6\%, 95\% confidence interval = -367.0 to -52.2\%, p < 0.000). Co-activation showed significant lower values for perturbed compared to normal walking (p < 0.000), without significant gender differences for both walking conditions. GM activated significantly earlier than TA and PL (p < 0.01) without significant differences between the muscle activation onsets of men and women (p = 0.7). The results reflect that activation strategies of the ankle encompassing muscles differ between genders. In provoked stumbling, higher PL EMG activity in women compared to men is present. Future studies should aim to elucidate if this specific behavior has any relationship with ankle injury occurrence between genders.},
  language  = {en}
}
@article{MuellerMuellerStolletal.2016,
  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},
  series = {BMC sports science, medicine \& rehabilitation},
  volume    = {8},
  journal   = {BMC sports science, medicine \& rehabilitation},
  publisher = {BioMed Central},
  address   = {London},
  issn      = {2052-1847},
  doi       = {10.1186/s13102-016-0064-7},
  pages     = {5},
  year      = {2016},
  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}
}
@article{MuellerStollMuelleretal.2012,
  author    = {M{\"u}ller, Steffen and Stoll, Josefine and M{\"u}ller, Juliane and Mayer, Frank},
  title     = {Validity of isokinetic trunk measurements with respect to healthy adults, athletes and low back pain patients},
  series = {Isokinetics and exercise science : official journal of the European Isokinetic Society},
  volume    = {20},
  journal   = {Isokinetics and exercise science : official journal of the European Isokinetic Society},
  number    = {4},
  publisher = {IOS Press},
  address   = {Amsterdam},
  issn      = {0959-3020},
  doi       = {10.3233/IES-2012-00482},
  pages     = {255 -- 266},
  year      = {2012},
  abstract  = {Background: Isokinetic measurements are widely used to assess strength capacity in a clinical or research context. Nevertheless, the validity of isokinetic measures for identifying strength deficits and the evaluation of therapeutic process regarding different pathologies is yet to be established. Therefore, the purpose of this review is to evaluate the validity of isokinetic measures in a specific case: that of muscular capacity in low back pain (LBP). Methods: A literature search (PubMed; ISI Web of Knowledge; The Cochrane Library) covering the last 10 years was performed. Relevant papers regarding isokinetic trunk strength measures in healthy and patients with low back pain (PLBP) were searched. Peak torque values [Nm] and peak torque normalized to body weight [Nm/kg BW] were extracted for healthy and PLBP. Ranked mean values across studies were calculated for the concentric peak torque at 60 degrees/s as well as the flexion/extension (F/E) ratio. Results: 34 publications (31 flexion/extension; 3 rotation) were suitable for reporting detailed isokinetic strength measures in healthy or LBP (untrained adults, adolescents, athletes). Adolescents and athletes were different compared to normal adults in terms of absolute trunk strength values and the F/E ratio. Furthermore, isokinetic measures evaluating therapeutic process and isokinetic rehabilitation training were infrequent in literature (8 studies). Conclusion: Isokinetic measurements are valid for measuring trunk flexion/extension strength and F/E ratio in athletes, adolescents and (untrained) adults with/without LBP. The validity of trunk rotation is questionable due to a very small number of publications whereas no reliable source regarding lateral flexion could be traced. Therefore, isokinetic dynamometry may be utilized for identifying trunk strength deficits in healthy adults and PLBP.},
  language  = {en}
}
@article{MuellerStollMuelleretal.2017,
  author    = {M{\"u}ller, Steffen and Stoll, Josefine and Mueller, Juliane and Cassel, Michael and Mayer, Frank},
  title     = {Trunk Muscle Activity during Drop Jump Performance in Adolescent Athletes with Back Pain},
  series = {Frontiers in physiology},
  volume    = {8},
  journal   = {Frontiers in physiology},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne},
  issn      = {1664-042X},
  doi       = {10.3389/fphys.2017.00274},
  pages     = {124 -- 132},
  year      = {2017},
  abstract  = {In the context of back pain, great emphasis has been placed on the importance of trunk stability, especially in situations requiring compensation of repetitive, intense loading induced during high-performance activities, e.g., jumping or landing. This study aims to evaluate trunk muscle activity during drop jump in adolescent athletes with back pain (BP) compared to athletes without back pain (NBP). Eleven adolescent athletes suffering back pain (BP: m/f: n = 4/7; 15.9 +/- 1.3 y; 176 +/- 11 cm; 68 +/- 11 kg; 12.4 +/- 10.5 h/we training) and 11 matched athletes without back pain (NBP: m/f: n = 4/7; 15.5 +/- 1.3 y; 174 +/- 7 cm; 67 +/- 8 kg; 14.9 +/- 9.5 h/we training) were evaluated. Subjects conducted 3 drop jumps onto a force plate (ground reaction force). Bilateral 12-lead SEMG (surface Electromyography) was applied to assess trunk muscle activity. Ground contact time [ms], maximum vertical jump force [N], jump time [ms] and the jump performance index [m/s] were calculated for drop jumps. SEMG amplitudes (RMS: root mean square [\%]) for all 12 single muscles were normalized toMIVC (maximum isometric voluntary contraction) and analyzed in 4 time windows (100 ms pre- and 200 ms post-initial ground contact, 100 ms pre- and 200 ms post-landing) as outcome variables. In addition, muscles were grouped and analyzed in ventral and dorsal muscles, as well as straight and transverse trunk muscles. Drop jump ground reaction force variables did not differ between NBP and BP (p > 0.05). Mm obliquus externus and internus abdominis presented higher SEMG amplitudes (1.3-1.9-fold) for BP (p < 0.05). Mm rectus abdominis, erector spinae thoracic/lumbar and latissimus dorsi did not differ (p > 0.05). The muscle group analysis over the whole jumping cycle showed statistically significantly higher SEMG amplitudes for BP in the ventral (p = 0.031) and transverse muscles (p = 0.020) compared to NBP. Higher activity of transverse, but not straight, trunk muscles might indicate a specific compensation strategy to support trunk stability in athletes with back pain during drop jumps. Therefore, exercises favoring the transverse trunk muscles could be recommended for back pain treatment.},
  language  = {en}
}
@article{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 = {PLoS ONE},
  volume    = {14},
  journal   = {PLoS ONE},
  number    = {8},
  publisher = {PLOS 1},
  address   = {San Francisco},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0221346},
  pages     = {15},
  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}
}
@article{MuellerMuellerStolletal.2017,
  author    = {M{\"u}ller, Juliane and M{\"u}ller, Steffen and Stoll, Josefine and Fr{\"o}hlich, K. and Otto, Christoph and Mayer, Frank},
  title     = {Back pain prevalence in adolescent athletes},
  series = {Scandinavian journal of medicine \& science in sports},
  volume    = {27},
  journal   = {Scandinavian journal of medicine \& science in sports},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0905-7188},
  doi       = {10.1111/sms.12664},
  pages     = {448 -- 454},
  year      = {2017},
  abstract  = {The research aimed to investigate back pain (BP) prevalence in a large cohort of young athletes with respect to age, gender, and sport discipline. BP (within the last 7days) was assessed with a face scale (face 1-2=no pain; face 3-5=pain) in 2116 athletes (m/f 61\%/39\%; 13.3 +/- 1.7years; 163.0 +/- 11.8cm; 52.6 +/- 13.9kg; 4.9 +/- 2.7 training years; 8.4 +/- 5.7 training h/week). Four different sports categories were devised (a: combat sports, b: game sports; c: explosive strength sport; d: endurance sport). Analysis was described descriptively, regarding age, gender, and sport. In addition, 95\% confidence intervals (CI) were calculated. About 168 (8\%) athletes were allocated into the BP group. About 9\% of females and 7\% of males reported BP. Athletes, 11-13years, showed a prevalence of 2-4\%; while prevalence increased to 12-20\% in 14- to 17-year olds. Considering sport discipline, prevalence ranged from 3\% (soccer) to 14\% (canoeing). Prevalences in weight lifting, judo, wrestling, rowing, and shooting were 10\%; in boxing, soccer, handball, cycling, and horse riding, 6\%. 95\% CI ranged between 0.08-0.11. BP exists in adolescent athletes, but is uncommon and shows no gender differences. A prevalence increase after age 14 is obvious. Differentiated prevention programs in daily training routines might address sport discipline-specific BP prevalence.},
  language  = {en}
}
@inproceedings{TorlakTorlakAppiahDwomohetal.2014,
  author    = {Torlak, Firdevs and Torlak, Firdevs and Appiah-Dwomoh, Edem Korkor and Engel, Tilman and Stoll, Josefine and M{\"u}ller, Juliane and Mayer, Frank},
  title     = {Gender differences in lower leg muscular activity during provoked stumbling - a pilot study},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {46},
  booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  number    = {5},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {0195-9131},
  pages     = {728 -- 728},
  year      = {2014},
  language  = {en}
}