@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{CarlsohnWeberMuelleretal.2012, author = {Carlsohn, Anja and Weber, Josefine and M{\"u}ller, Juliane and Stuwe, Anja and M{\"u}ller, Steffen and Mayer, Frank}, title = {Dietary intake to reduce body mass before competition in german judo athletes}, series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine}, volume = {44}, booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {0195-9131}, pages = {109 -- 109}, year = {2012}, language = {en} } @inproceedings{AppiahDwomohTorlakEngeletal.2014, author = {Appiah-Dwomoh, Edem Korkor and Torlak, Firdevs and Engel, Tilman and Stoll, Josefine and M{\"u}ller, Juliane and Mayer, Frank}, title = {Does perturbed treadmill walking lead to emg-changes of the lower extremity?}, 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 = {827 -- 827}, year = {2014}, 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{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} } @inproceedings{MuellerWeberOttoetal.2012, author = {M{\"u}ller, Juliane and Weber, Josefine and Otto, Christoph and M{\"u}ller, Steffen and Mayer, Frank}, title = {Effects of six-month trunk stability exercises on low back pain prevalence in young athletes}, series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine}, volume = {44}, booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {0195-9131}, pages = {601 -- 601}, year = {2012}, language = {en} } @article{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}, series = {PLoS one}, volume = {12}, journal = {PLoS one}, number = {3}, publisher = {PLoS}, address = {Lawrence, Kan.}, issn = {1932-6203}, doi = {10.1371/journal.pone.0174034}, 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{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} } @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} } @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} } @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{MugelePlummerSteffenetal.2018, author = {Mugele, Hendrick 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} } @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} } @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{MuellerMuellerStolletal.2016, author = {M{\"u}ller, Juliane and M{\"u}ller, Steffen and Stoll, Josefine and Rector, Michael V. and Baur, Heiner and Mayer, Frank}, title = {Influence of Load on Three-Dimensional Segmental Trunk Kinematics in One-Handed Lifting: A Pilot Study}, series = {Journal of applied biomechanics}, volume = {32}, journal = {Journal of applied biomechanics}, publisher = {Human Kinetics Publ.}, address = {Champaign}, issn = {1065-8483}, doi = {10.1123/jab.2015-0227}, pages = {520 -- 525}, year = {2016}, abstract = {Stability of the trunk is relevant in determining trunk response to different loading in everyday tasks initiated by the limbs. Descriptions of the trunk's mechanical movement patterns in response to different loads while lifting objects are still under debate. Hence, the aim of this study was to analyze the influence of weight on 3-dimensional segmental motion of the trunk during 1-handed lifting. Ten asymptomatic subjects were included (29 ± 3 y; 1.79 ± 0.09 m; 75 ± 14 kg). Subjects lifted 3× a light and heavy load from the ground up onto a table. Three-dimensional segmental trunk motion was measured (12 markers; 3 segments: upper thoracic area [UTA], lower thoracic area [LTA], lumbar area [LA]). Outcomes were total motion amplitudes (ROM;[°]) for anterior flexion, lateral flexion, and rotation of each segment. The highest ROM was observed in the LTA segment (anterior flexion), and the smallest ROM in the UTA segment (lateral flexion). ROM differed for all planes between the 3 segments for both tasks (P < .001). There were no differences in ROM between light and heavy loads (P > .05). No interaction effects (load × segment) were observed, as ROM did not reveal differences between loading tasks. Regardless of weight, the 3 segments did reflect differences, supporting the relevance of multisegmental analysis.}, 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} } @article{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}, series = {PLoS one}, volume = {11}, journal = {PLoS one}, number = {2}, publisher = {Public Library of Science}, address = {Lawrence, Kan.}, issn = {1932-6203}, doi = {10.1371/journal.pone.0149924}, 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} } @article{MuellerMuellerBauretal.2013, author = {M{\"u}ller, Juliane and M{\"u}ller, Steffen and Baur, Heiner and Mayer, Frank}, title = {Intra-individual gait speed variability in healthy children aged 1-15 years}, series = {Gait \& posture}, volume = {38}, journal = {Gait \& posture}, number = {4}, publisher = {Elsevier}, address = {Clare}, issn = {0966-6362}, doi = {10.1016/j.gaitpost.2013.02.011}, pages = {631 -- 636}, year = {2013}, abstract = {Introduction: Gait speed is one of the most commonly and frequently used parameters to evaluate gait development. It is characterized by high variability when comparing different steps in children. The objective of this study was to determine intra-individual gait speed variability in children. Methods: Gait speed measurements (6-10 trials across a 3 m walkway) were performed and analyzed in 8263 children, aged 1-15 years. The coefficient of variation (CV) served as a measure for intra-individual gait speed variability measured in 6.6 +/- 1.0 trials per child. Multiple linear regression analysis was conducted to evaluate the influence of age and body height on changes in variability. Additionally, a subgroup analysis for height within the group of 6-year-old children was applied. Results: A successive reduction in gait speed variability (CV) was observed for age groups (age: 1-15 years) and body height groups (height: 0.70-1.90 m). The CV in the oldest subjects was only one third of the CV (CV 6.25 +/- 3.52\%) in the youngest subjects (CV 16.58 +/- 10.01\%). Up to the age of 8 years (or 1.40 m height) there was a significant reduction in CV over time, compared to a leveling off for the older (taller) children. Discussion: The straightforward approach measuring gait speed variability in repeated trials might serve as a fundamental indicator for gait development in children. Walking velocity seems to increase to age 8. Enhanced gait speed consistency of repeated trials develops up to age 15.}, language = {en} } @article{VerchHirschmuellerMuelleretal.2018, author = {Verch, Ronald and Hirschm{\"u}ller, Anja and M{\"u}ller, Juliane and Baur, Heiner and Mayer, Frank and M{\"u}ller, Steffen}, title = {Is in-toing gait physiological in children?}, series = {Gait \& posture}, volume = {66}, journal = {Gait \& posture}, publisher = {Elsevier}, address = {Clare}, issn = {0966-6362}, doi = {10.1016/j.gaitpost.2018.08.019}, pages = {70 -- 75}, year = {2018}, abstract = {Research question: This study aimed to establish reference values in 1-14 year old healthy children and to implement FPA-percentile curves for daily clinical use. Methods: 5910 healthy children performed at least 3 repetitions of barefoot walking over an instrumented walkway using a pressure measurement platform. The FPA [degrees] was extracted and analyzed by age and gender (mean +/- standard deviation; median with percentiles, MANOVA (age, gender) and Wilcoxon-Signed-Rank test for intra-individual side differences (alpha = 0.05). Results: FPA maximum was observed in 2-year-old children and diminished significant until the age of 4 to moderate out-toeing. For ages 5-14, no statistically significant differences in FPA values were present (p > 0.05). MANOVA confirmed age (p < 0.001) and gender (p < 0.001) as significant FPA influencing factors, without combined effect (p > 0.05). In every age group, right feet showed significantly greater out-toeing (p < 0.05). Significance: Percentile values indicate a wide FPA range in children. FPA development in young children shows a spontaneous shift towards moderate external rotation (age 2-4), whereby in-toeing <= 1-5 degrees can be present, but can return to normal. Bilateral in-toeing after the age of four and unilateral in-toeing after the age of seven should be monitored.}, language = {en} } @article{MuellerEngelKopinskietal.2017, author = {M{\"u}ller, Juliane and Engel, Tilman and Kopinski, Stephan and Mayer, Frank and M{\"u}ller, Steffen}, title = {Neuromuscular trunk activation patterns in back pain patients during one-handed lifting}, series = {World journal of orthopedics}, volume = {8}, journal = {World journal of orthopedics}, number = {2}, publisher = {Baishideng Publishing Group}, address = {Pleasanton}, issn = {2218-5836}, doi = {10.5312/wjo.v8.i2.142}, pages = {142 -- 148}, year = {2017}, abstract = {AIM To analyze neuromuscular activity patterns of the trunk in healthy controls (H) and back pain patients (BPP) during one-handed lifting of light to heavy loads. METHODS RESULTS Seven subjects (3m/4f; 32 +/- 7 years; 171 +/- 7 cm; 65 +/- 11 kg) were assigned to BPP (pain grade >= 2) and 36 (13m/23f; 28 +/- 8 years; 174 +/- 10 cm; 71 +/- 12 kg) to H (pain grade <= 1). H and BPP did not differ significantly in anthropometrics (P > 0.05). All subjects were able to lift the light and middle loads, but 57\% of BPP and 22\% of H were not able to lift the heavy load (all women) chi(2) analysis revealed statistically significant differences in task failure between H vs BPP (P = 0.03). EMG-RMS ranged from 33\% +/- 10\%/30\% +/- 9\% (DL, 1 kg) to 356\% +/- 148\%/283\% +/- 80\% (VR, 20 kg) in H/BPP with no statistical difference between groups regardless of load (P > 0.05). However, the EMG-RMS of the VR was greatest in all lifting tasks for both groups and increased with heavier loads. CONCLUSION Heavier loading leads to an increase (2-to 3-fold) in trunk muscle activity with comparable patterns. Heavy loading (20 kg) leads to task failure, especially in women with back pain.}, 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} } @article{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 = {Frontiers in Physiology}, volume = {10}, journal = {Frontiers in Physiology}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-042X}, doi = {10.3389/fphys.2019.00544}, 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} } @inproceedings{HainMuellerMuelleretal.2013, author = {Hain, Gerrit and M{\"u}ller, Juliane and M{\"u}ller, Steffen and Reschke, Antje and Mayer, Frank}, title = {Reliability of an in-vivo 3-segmental kinematic trunk model in a one-handed lifting task}, series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine}, volume = {45}, 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 = {174 -- 174}, year = {2013}, language = {en} } @article{MuellerEngelMuelleretal.2018, author = {Mueller, Steffen and Engel, Tilman and M{\"u}ller, Juliane and Stoll, Josefine and Baur, Heiner and Mayer, Frank}, title = {Sensorimotor exercises and enhanced trunk function}, series = {International journal of sports medicine}, volume = {39}, journal = {International journal of sports medicine}, number = {7}, publisher = {Thieme}, address = {Stuttgart}, issn = {0172-4622}, doi = {10.1055/a-0592-7286}, pages = {555 -- 563}, year = {2018}, abstract = {The aim of this study was to investigate the effect of a 6-week sensorimotor or resistance training on maximum trunk strength and response to sudden, high-intensity loading in athletes. Interventions showed no significant difference for maximum strength in concentric and eccentric testing (p>0.05). For perturbation compensation, higher peak torque response following SMT (Extension: +24Nm 95\%CI +/- 19Nm; Rotation: + 19Nm 95\%CI +/- 13Nm) and RT (Extension: +35Nm 95\%CI +/- 16Nm; Rotation: +5Nm 95\%CI +/- 4Nm) compared to CG (Extension: -4Nm 95\%CI +/- 16Nm; Rotation: -2Nm 95\%CI +/- 4Nm) was present (p<0.05).}, language = {en} } @article{MuellerCarlsohnMuelleretal.2012, author = {M{\"u}ller, Steffen and Carlsohn, Anja and M{\"u}ller, Juliane and Baur, Heiner and Mayer, Frank}, title = {Static and dynamic foot characteristics in children aged 1-13 years a cross-sectional study}, series = {Gait \& posture}, volume = {35}, journal = {Gait \& posture}, number = {3}, publisher = {Elsevier}, address = {Clare}, issn = {0966-6362}, doi = {10.1016/j.gaitpost.2011.10.357}, pages = {389 -- 394}, year = {2012}, abstract = {The aim of this study was to acquire static and dynamic foot geometry and loading in childhood, and to establish data for age groups of a population of 1-13 year old infants and children. A total of 10,382 children were recruited and 7788 children (48\% males and 52\% females) were finally included into the data analysis. For static foot geometry foot length and foot width were quantified in a standing position. Dynamic foot geometry and loading were assessed during walking on a walkway with self selected speed (Novel Emed X, 100 Hz, 4 sensors/cm(2)). Contact area (CA), peak pressure (PP), force time integral (FTI) and the arch index were calculated for the total, fore-, mid- and hindfoot. Results show that most static and dynamic foot characteristics change continuously during growth and maturation. Static foot length and width increased with age from 13.1 +/- 0.8 cm (length) and 5.7 +/- 0.4 cm (width) in the youngest to 24.4 +/- 1.5 cm (length) and 8.9 +/- 0.6 cm (width) in the oldest. A mean walking velocity of 0.94 +/- 0.25 m/s was observed. Arch-index ranged from 0.32 +/- 0.04 [a.u.] in the one-year old to 0.21 +/- 0.13 [a.u.] in the 5-year olds and remains constant afterwards. This study provides data for static and dynamic foot characteristics in children based on a cohort of 7788 subjects. Static and dynamic foot measures change differently during growth and maturation. Dynamic foot measurements provide additional information about the children's foot compared to static measures.}, language = {en} } @article{MuellerMuellerEngeletal.2016, author = {M{\"u}ller, Juliane and M{\"u}ller, Steffen and Engel, Tilman and Reschke, Antje and Baur, Heiner and Mayer, Frank}, title = {Stumbling reactions during perturbed walking: Neuromuscular reflex activity and 3-D kinematics of the trunk - A pilot study}, series = {Journal of biomechanics}, volume = {49}, journal = {Journal of biomechanics}, publisher = {Elsevier}, address = {Oxford}, issn = {0021-9290}, doi = {10.1016/j.jbiomech.2015.09.041}, pages = {933 -- 938}, year = {2016}, abstract = {Stumbling led to an increase in ROM, compared to unperturbed gait, in all segments and planes. These increases ranged between 107 +/- 26\% (UTA/rotation) and 262 +/- 132\% (UTS/lateral flexion), significant only in lateral flexion. EMG activity of the trunk was increased during stumbling (abdominal: 665 +/- 283\%; back: 501 +/- 215\%), without significant differences between muscles. Provoked stumbling leads to a measurable effect on the trunk, quantifiable by an increase in ROM and EMG activity, compared to normal walking. Greater abdominal muscle activity and ROM of lateral flexion may indicate a specific compensation pattern occurring during stumbling. (C) 2015 Elsevier Ltd. All rights reserved.}, language = {en} } @inproceedings{WeberMuellerOttoetal.2012, author = {Weber, Josefine and M{\"u}ller, Juliane and Otto, Christoph and Scharhag-Rosenberger, Friederike and Carlsohn, Anja and Mayer, Frank}, title = {Test-retest-reliability of metabolic and cardiovascular load during isokinetic strength testing}, series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine}, volume = {44}, booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {0195-9131}, pages = {375 -- 376}, year = {2012}, language = {en} } @inproceedings{ReschkeMuellerMuelleretal.2013, author = {Reschke, Antje and M{\"u}ller, Juliane and M{\"u}ller, Steffen and Engel, Tilman and Mayer, Frank}, title = {Three-dimensional spine kinematics during perturbed treadmill walking - a pilot study}, series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine}, volume = {45}, 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 = {172 -- 172}, year = {2013}, language = {en} } @article{MuellerMuellerStolletal.2014, author = {M{\"u}ller, Juliane and M{\"u}ller, Steffen and Stoll, Josefine and Baur, Heiner and Mayer, Frank}, title = {Trunk extensor and flexor strength capacity in healthy young elite athletes aged 11-15 Years}, series = {Journal of strength and conditioning research : the research journal of the NSCA}, volume = {28}, journal = {Journal of strength and conditioning research : the research journal of the NSCA}, number = {5}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {1064-8011}, doi = {10.1519/JSC.0000000000000280}, pages = {1328 -- 1334}, year = {2014}, abstract = {Mueller, J, Mueller, S, Stoll, J, Baur, H, and Mayer, F. Trunk extensor and flexor strength capacity in healthy young elite athletes aged 11-15 years. J Strength Cond Res 28(5): 1328-1334, 2014-Differences in trunk strength capacity because of gender and sports are well documented in adults. In contrast, data concerning young athletes are sparse. The purpose of this study was to assess the maximum trunk strength of adolescent athletes and to investigate differences between genders and age groups. A total of 520 young athletes were recruited. Finally, 377 (n = 233/144 M/F; 13 +/- 1 years; 1.62 +/- 0.11 m height; 51 +/- 12 kg mass; training: 4.5 +/- 2.6 years; training sessions/week: 4.3 +/- 3.0; various sports) young athletes were included in the final data analysis. Furthermore, 5 age groups were differentiated (age groups: 11, 12, 13, 14, and 15 years; n = 90, 150, 42, 43, and 52, respectively). Maximum strength of trunk flexors (Flex) and extensors (Ext) was assessed in all subjects during isokinetic concentric measurements (60 degrees center dot s(-1); 5 repetitions; range of motion: 55 degrees). Maximum strength was characterized by absolute peak torque (Flex(abs), Ext(abs); N center dot m), peak torque normalized to body weight (Flex(norm), Ext(norm); N center dot m center dot kg(-1) BW), and Flex(abs)/Ext(abs) ratio (RKquot). Descriptive data analysis (mean +/- SD) was completed, followed by analysis of variance (alpha = 0.05; post hoc test [Tukey-Kramer]). Mean maximum strength for all athletes was 97 +/- 34 N center dot m in Flex(abs) and 140 +/- 50 N center dot m in Ext(abs) (Flex(norm) = 1.9 +/- 0.3 N center dot m center dot kg(-1) BW, Ext(norm) = 2.8 +/- 0.6 N center dot m center dot kg(-1) BW). Males showed statistically significant higher absolute and normalized values compared with females (p < 0.001). Flex(abs) and Ext(abs) rose with increasing age almost 2-fold for males and females (Flex(abs), Ext(abs): p < 0.001). Flex(norm) and Ext(norm) increased with age for males (p < 0.001), however, not for females (Flex(norm): p = 0.26; Ext(norm): p = 0.20). RKquot (mean +/- SD: 0.71 +/- 0.16) did not reveal any differences regarding age (p = 0.87) or gender (p = 0.43). In adolescent athletes, maximum trunk strength must be discussed in a gender- and age-specific context. The Flex(abs)/Ext(abs) ratio revealed extensor dominance, which seems to be independent of age and gender. The values assessed may serve as a basis to evaluate and discuss trunk strength in athletes.}, language = {en} } @inproceedings{MuellerCasselMuelleretal.2014, author = {M{\"u}ller, Steffen and Cassel, Michael and M{\"u}ller, Juliane and Stoll, Josefine and Baur, Heiner and Mayer, Frank}, title = {Trunk strength in adolescent athletes with Spondylolisthesis with/without back pain during training: 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 = {642 -- 642}, year = {2014}, language = {en} } @inproceedings{EngelMuellerMuelleretal.2013, author = {Engel, Tilman and M{\"u}ller, Juliane and M{\"u}ller, Steffen and Reschke, Antje and Kopinski, Stephan and Mayer, Frank}, title = {Validity and reliability of a new customised split-belt treadmill provoking unexpected walking perturbations}, series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine}, volume = {45}, 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 = {462 -- 462}, year = {2013}, 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} }