TY - CHAP A1 - Appiah-Dwomoh, Edem Korkor A1 - Torlak, Firdevs A1 - Engel, Tilman A1 - Stoll, Josefine A1 - Müller, Juliane A1 - Mayer, Frank T1 - Does perturbed treadmill walking lead to emg-changes of the lower extremity? T2 - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine Y1 - 2014 SN - 0195-9131 SN - 1530-0315 VL - 46 IS - 5 SP - 827 EP - 827 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - CHAP A1 - Carlsohn, Anja A1 - Weber, Josefine A1 - Müller, Juliane A1 - Stuwe, Anja A1 - Müller, Steffen A1 - Mayer, Frank T1 - Dietary intake to reduce body mass before competition in german judo athletes T2 - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine Y1 - 2012 SN - 0195-9131 VL - 44 SP - 109 EP - 109 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - GEN A1 - Cassel, Michael A1 - Müller, Juliane A1 - Moser, Othmar A1 - Strempler, Mares Elaine A1 - Reso, Judith A1 - Mayer, Frank T1 - Orthopedic Injury Profiles in Adolescent Elite Athletes BT - A Retrospective Analysis From a Sports Medicine Department T2 - Postprints der Universität Potsdam Humanwissenschaftliche Reihe N2 - 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. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 559 KW - overuse injuries KW - epidemiology KW - complaints KW - symptoms KW - risk factors KW - sports Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-434953 SN - 1866-8364 IS - 559 ER - TY - JOUR A1 - Cassel, Michael A1 - Müller, Juliane A1 - Moser, Othmar A1 - Strempler, Mares Elaine A1 - Reso, Judith A1 - Mayer, Frank T1 - Orthopedic Injury Profiles in Adolescent Elite Athletes BT - A Retrospective Analysis From a Sports Medicine Department JF - Frontiers in Physiology N2 - 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. KW - overuse injuries KW - epidemiology KW - complaints KW - symptoms KW - risk factors KW - sports Y1 - 2019 U6 - https://doi.org/10.3389/fphys.2019.00544 SN - 1664-042X VL - 10 PB - Frontiers Research Foundation CY - Lausanne ER - TY - CHAP A1 - Engel, Tilman A1 - Müller, Juliane A1 - Müller, Steffen A1 - Reschke, Antje A1 - Kopinski, Stephan A1 - Mayer, Frank T1 - Validity and reliability of a new customised split-belt treadmill provoking unexpected walking perturbations T2 - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine Y1 - 2013 SN - 0195-9131 SN - 1530-0315 VL - 45 IS - 5 SP - 462 EP - 462 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - CHAP A1 - Hain, Gerrit A1 - Müller, Juliane A1 - Müller, Steffen A1 - Reschke, Antje A1 - Mayer, Frank T1 - Reliability of an in-vivo 3-segmental kinematic trunk model in a one-handed lifting task T2 - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine Y1 - 2013 SN - 0195-9131 SN - 1530-0315 VL - 45 IS - 5 SP - 174 EP - 174 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - JOUR A1 - Mueller, Steffen A1 - Engel, Tilman A1 - Müller, Juliane A1 - Stoll, Josefine A1 - Baur, Heiner A1 - Mayer, Frank T1 - Sensorimotor exercises and enhanced trunk function BT - a randomized controlled trial JF - International journal of sports medicine N2 - 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). KW - core KW - training intervention KW - prevention KW - perturbation KW - MiSpEx* Y1 - 2018 U6 - https://doi.org/10.1055/a-0592-7286 SN - 0172-4622 SN - 1439-3964 VL - 39 IS - 7 SP - 555 EP - 563 PB - Thieme CY - Stuttgart ER - TY - JOUR A1 - Mugele, Hendrick A1 - Plummer, Ashley A1 - Steffen, Kathrin A1 - Stoll, Josefine A1 - Mayer, Frank A1 - Müller, Juliane T1 - General versus sports-specific injury prevention programs in athletes BT - A systematic review on the effect on injury rates JF - PLOS ONE N2 - 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. KW - randomized-controlled-trial KW - cruciate ligament injury KW - amateur soccer players KW - hamstring injuries KW - training-program KW - exercise program KW - adolescent sport KW - youth football KW - team handball KW - risk-factors Y1 - 2018 U6 - https://doi.org/10.1371/journal.pone.0205635 SN - 1932-6203 VL - 13 IS - 10 SP - 1 EP - 16 PB - Public Library of Science CY - San Francisco ER - TY - GEN A1 - Mugele, Hendrik A1 - Plummer, Ashley A1 - Steffen, Kathrin A1 - Stoll, Josefine A1 - Mayer, Frank A1 - Müller, Juliane T1 - General versus sports-specific injury prevention programs in athletes BT - A systematic review on the effect on injury rates T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - 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. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 481 KW - randomized-controlled-trial KW - cruciate ligament injury KW - amateur soccer players KW - hamstring injuries KW - training-program KW - exercise program KW - adolescent sport KW - youth football KW - team handball KW - risk-factors Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-419935 IS - 481 ER - TY - THES A1 - Müller, Juliane T1 - Trunk loading and back pain T1 - Rumpfbelastungen und Rückenschmerzen BT - three-dimensional motion analysis and evaluation of neuromuscular reflex activity in response to sudden and continuous loading BT - dreidimensionale Bewegungsanalyse und Erfassung der neuromuskulären Aktivität des Rumpfes als Antwort auf plötzliche und kontinuierliche Belastungen N2 - An essential function of the trunk is the compensation of external forces and loads in order to guarantee stability. Stabilising the trunk during sudden, repetitive loading in everyday tasks, as well as during performance is important in order to protect against injury. Hence, reduced trunk stability is accepted as a risk factor for the development of back pain (BP). An altered activity pattern including extended response and activation times as well as increased co-contraction of the trunk muscles as well as a reduced range of motion and increased movement variability of the trunk are evident in back pain patients (BPP). These differences to healthy controls (H) have been evaluated primarily in quasi-static test situations involving isolated loading directly to the trunk. Nevertheless, transferability to everyday, dynamic situations is under debate. Therefore, the aim of this project is to analyse 3-dimensional motion and neuromuscular reflex activity of the trunk as response to dynamic trunk loading in healthy (H) and back pain patients (BPP). A measurement tool was developed to assess trunk stability, consisting of dynamic test situations. During these tests, loading of the trunk is generated by the upper and lower limbs with and without additional perturbation. Therefore, lifting of objects and stumbling while walking are adequate represents. With the help of a 12-lead EMG, neuromuscular activity of the muscles encompassing the trunk was assessed. In addition, three-dimensional trunk motion was analysed using a newly developed multi-segmental trunk model. The set-up was checked for reproducibility as well as validity. Afterwards, the defined measurement set-up was applied to assess trunk stability in comparisons of healthy and back pain patients. Clinically acceptable to excellent reliability could be shown for the methods (EMG/kinematics) used in the test situations. No changes in trunk motion pattern could be observed in healthy adults during continuous loading (lifting of objects) of different weights. In contrast, sudden loading of the trunk through perturbations to the lower limbs during walking led to an increased neuromuscular activity and ROM of the trunk. Moreover, BPP showed a delayed muscle response time and extended duration until maximum neuromuscular activity in response to sudden walking perturbations compared to healthy controls. In addition, a reduced lateral flexion of the trunk during perturbation could be shown in BPP. It is concluded that perturbed gait seems suitable to provoke higher demands on trunk stability in adults. The altered neuromuscular and kinematic compensation pattern in back pain patients (BPP) can be interpreted as increased spine loading and reduced trunk stability in patients. Therefore, this novel assessment of trunk stability is suitable to identify deficits in BPP. Assignment of affected BPP to therapy interventions with focus on stabilisation of the trunk aiming to improve neuromuscular control in dynamic situations is implied. Hence, sensorimotor training (SMT) to enhance trunk stability and compensation of unexpected sudden loading should be preferred. N2 - Eine ausgeprägte Rumpfstabilität gilt als vorteilhaft, um den Rumpf bei repetitiven und plötzlich auftretenden hohen Lasten sowohl in Alltagssituationen, am Arbeitsplatz als auch während Training- oder Wettkampfbelastungen im Sport zu stabilisieren und vor Beschwerden bzw. Verletzungen zu schützen. Eine reduzierte Rumpfstabilität wird daher als Risikofaktor für die Entwicklung von Rückenschmerzen angenommen. Eine veränderte Aktivität (verlängerte Reaktionszeit, verlängerte Aktivierungszeiten, erhöhte Ko-Kontraktion) der rumpfumgreifenden Muskulatur sowie ein reduziertes Bewegungsausmaß und eine erhöhte -variabilität des Rumpfes bei Rückenschmerzpatienten sind evident. Diese Unterschiede sind hauptsächlich in quasi-statischen Belastungssituationen mit isolierter Lasteinwirkung direkt am Rumpf nachgewiesen. Eine Übertragbarkeit auf alltagsnahe und dynamische Belastungssituationen ist jedoch kritisch zu hinterfragen. Ziel des Dissertationsprojektes ist die Entwicklung und Validierung eines Diagnostiktools zur Erhebung der Rumpfstabilität in dynamischen Belastungssituationen bei Gesunden und Rückenschmerzpatienten. Für die Erfassung der Rumpfstabilität wurde ein Mess-Verfahren bestehend aus dynamischen Belastungssituationen, in denen die Lasten über die Extremitäten generiert werden (Heben von Lasten, Perturbation im Gang), mit und ohne Perturbation entwickelt. Mit Hilfe eines 12-Kanal-EMGs wurde die neuromuskuläre Aktivität der rumpfumgreifenden Muskulatur erfasst. Zusätzlich wurde die 3-dimensonale Rumpfbewegung über ein neu entwickeltes multi-segmentales Rückenmodell analysiert. Dieses Methodensetup wurde auf Reproduzierbarkeit sowie Validität überprüft. Im Anschluss erfolgte eine Anwendung des definierten Diagnostiktools zur Erfassung der Rumpfstabilität im Vergleich von Probanden mit und ohne Rückenschmerzen. Eine klinisch akzeptable bis hervorragende Reliabilität konnte für die verwendeten Messvariablen (EMG/Kinematik) in den beschriebenen Belastungssituationen (Heben/Gang mit Perturbation) nachgewiesen werden. Gesunde Erwachsene zeigen bei einer kontinuierlichen Belastung des Rumpfes mit unterschiedlichen Gewichten (Heben von Lasten) keine Veränderung der Rumpfbewegung. Die plötzliche Belastung des Rumpfes durch Hinzunahme von Perturbationen der unteren Extremitäten im Gang konnte dagegen bei gesunden Probanden eine messbare Auslenkung des Rumpfes auf kinematischer als auch neuromuskulärer Ebene hervorrufen. Rückenschmerzpatienten zeigten ein verändertes neuromuskuläres und kinematisches Kompensationsmuster bei externen Perturbationen im Gang im Vergleich zu Gesunden. Dies ist charakterisiert durch eine verzögerte Reaktionszeit sowie verlängerte Dauer zum Erreichen der maximalen neuromuskulären Aktivität in Kombination mit einer reduzierten Lateralflexion des Rumpfes während Perturbation. Die gewählte Testsituation - Perturbation im Gang - scheint, trotz Applikation der Perturbation über die Extremitäten und fehlender Fixierung des Beckens, geeignet zur Provokation erhöhter Anforderungen an die Stabilisierung des Rumpfes bei erwachsenen Probanden. Das veränderte neuromuskuläre und kinematische Kompensationsmuster bei Rückenschmerzpatienten kann als Surrogat einer erhöhten Belastung sowie einer reduzierten Rumpfstabilität bei Patienten bewertet werden. Das neu entwickelte Verfahren zur Erfassung der Rumpfstabilität ist geeignet, um Defizite bei Rückenschmerzpatienten zu identifizieren und folglich individuelle Zuordnungen zu Trainingsmaßnahmen vorzunehmen. Der Fokus in der Prävention bzw. Therapie von Rückenschmerzen sollte dem Folgend auf der Stabilisierung des Rumpfes mit dem Ziel der Verbesserung der neuromuskulären Kontrolle des Rumpfes in dynamischen Situationen liegen. Ein sensomotorischer Trainingsansatz (SMT) zur Optimierung der Rumpfstabilität und Kompensationsfähigkeit von unerwarteten externen Lasten ist zu präferieren. KW - electromyography KW - trunk kinematics KW - spine KW - Wirbelsäule KW - Elektromyographie KW - Rumpfkinematik Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-102428 ER - TY - JOUR A1 - Müller, Juliane A1 - Engel, Tilman A1 - Kopinski, Stephan A1 - Mayer, Frank A1 - Müller, Steffen T1 - Neuromuscular trunk activation patterns in back pain patients during one-handed lifting JF - World journal of orthopedics N2 - 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. KW - Lifting KW - Core KW - Trunk KW - EMG KW - MISPEX Y1 - 2016 U6 - https://doi.org/10.5312/wjo.v8.i2.142 SN - 2218-5836 VL - 8 IS - 2 SP - 142 EP - 148 PB - Baishideng Publishing Group CY - Pleasanton ER - TY - JOUR A1 - Müller, Juliane A1 - Engel, Tilman A1 - Müller, Steffen A1 - Stoll, Josefine A1 - Baur, Heiner A1 - Mayer, Frank T1 - Effects of sudden walking perturbations on neuromuscular reflex activity and three-dimensional motion of the trunk in healthy controls and back pain symptomatic subjects JF - PLoS one N2 - 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. Y1 - 2017 U6 - https://doi.org/10.1371/journal.pone.0174034 SN - 1932-6203 VL - 12 IS - 3 PB - PLoS CY - Lawrence, Kan. ER - TY - GEN A1 - Müller, Juliane A1 - Engel, Tilman A1 - Müller, Steffen A1 - Stoll, Josefine A1 - Baur, Heiner A1 - Mayer, Frank T1 - Effects of sudden walking perturbations on neuromuscular reflex activity and three-dimensional motion of the trunk in healthy controls and back pain symptomatic subjects N2 - 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. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 317 Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-394931 ER - TY - JOUR A1 - Müller, Juliane A1 - Hadzic, Miralem A1 - Mugele, Hendrik A1 - Stoll, Josefine A1 - Müller, Steffen A1 - Mayer, Frank T1 - Effect of high-intensity perturbations during core-specific sensorimotor exercises on trunk muscle activation JF - Journal of biomechanics N2 - 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. KW - Split-belt treadmill KW - EMG KW - Core stability KW - MiSpEx Y1 - 2017 U6 - https://doi.org/10.1016/j.jbiomech.2017.12.013 SN - 0021-9290 SN - 1873-2380 VL - 70 SP - 212 EP - 218 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Müller, Juliane A1 - Müller, Steffen A1 - Baur, Heiner A1 - Mayer, Frank T1 - Intra-individual gait speed variability in healthy children aged 1-15 years JF - Gait & posture N2 - 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. KW - Development KW - Gait KW - Speed KW - Variability KW - Children Y1 - 2013 U6 - https://doi.org/10.1016/j.gaitpost.2013.02.011 SN - 0966-6362 SN - 1879-2219 VL - 38 IS - 4 SP - 631 EP - 636 PB - Elsevier CY - Clare ER - TY - JOUR A1 - Müller, Juliane A1 - Müller, Steffen A1 - Engel, Tilman A1 - Reschke, Antje A1 - Baur, Heiner A1 - Mayer, Frank T1 - Stumbling reactions during perturbed walking: Neuromuscular reflex activity and 3-D kinematics of the trunk - A pilot study JF - Journal of biomechanics N2 - 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. KW - Trunk kinematics KW - Treadmill walking KW - Gait perturbation KW - EMG Y1 - 2016 U6 - https://doi.org/10.1016/j.jbiomech.2015.09.041 SN - 0021-9290 SN - 1873-2380 VL - 49 SP - 933 EP - 938 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Müller, Juliane A1 - Müller, Steffen A1 - Stoll, Josefine A1 - Baur, Heiner A1 - Mayer, Frank T1 - Trunk extensor and flexor strength capacity in healthy young elite athletes aged 11-15 Years JF - Journal of strength and conditioning research : the research journal of the NSCA N2 - 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. KW - core KW - adolescents KW - isokinetic KW - strength performance Y1 - 2014 U6 - https://doi.org/10.1519/JSC.0000000000000280 SN - 1064-8011 SN - 1533-4287 VL - 28 IS - 5 SP - 1328 EP - 1334 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - JOUR A1 - Müller, Juliane A1 - Müller, Steffen A1 - Stoll, Josefine A1 - Fröhlich, K. A1 - Otto, Christoph A1 - Mayer, Frank T1 - Back pain prevalence in adolescent athletes JF - Scandinavian journal of medicine & science in sports N2 - 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. KW - Young athletes KW - back pain KW - prevalence KW - types of sports Y1 - 2017 U6 - https://doi.org/10.1111/sms.12664 SN - 0905-7188 SN - 1600-0838 VL - 27 SP - 448 EP - 454 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Müller, Juliane A1 - Müller, Steffen A1 - Stoll, Josefine A1 - Rector, Michael V. A1 - Baur, Heiner A1 - Mayer, Frank T1 - Influence of Load on Three-Dimensional Segmental Trunk Kinematics in One-Handed Lifting: A Pilot Study JF - Journal of applied biomechanics N2 - 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. KW - trunk motion KW - kinematic trunk model KW - everyday task KW - MiSpEx* Y1 - 2016 U6 - https://doi.org/10.1123/jab.2015-0227 SN - 1065-8483 SN - 1543-2688 VL - 32 SP - 520 EP - 525 PB - Human Kinetics Publ. CY - Champaign ER - TY - JOUR A1 - Müller, Juliane A1 - Stoll, Josefine A1 - Mueller, Steffen A1 - Mayer, Frank T1 - Dose-response relationship of core-specific sensorimotor interventions in healthy, well-trained participants BT - study protocol for a (MiSpEx) randomized controlled trial JF - Trials N2 - 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. KW - Sensorimotor training KW - Perturbation KW - Exercise KW - MiSpEx Y1 - 2018 U6 - https://doi.org/10.1186/s13063-018-2799-9 SN - 1745-6215 VL - 19 PB - BMC CY - London ER -