TY - JOUR A1 - Wochatz, Monique A1 - Engel, Tilman A1 - Müller, Steffen A1 - Mayer, Frank T1 - Alterations in scapular kinematics and scapular muscle activity after fatiguing shoulder flexion and extension movements JF - Medicine and science in sports and exercise : MSSE N2 - Repetitive overhead motions in combination with heavy loading were identified as risk factors for the development of shoulder pain. However, the underlying mechanism is not fully understood. Altered scapular kinematics as a result of muscle fatigue is suspected to be a contributor. PURPOSE: To determine scapular kinematics and scapular muscle activity at the beginning and end of constant shoulder flexion and extension loading in asymptomatic individuals. METHODS: Eleven asymptomatic adults (28±4yrs; 1.74±0.13m; 74±16kg) underwent maximum isokinetic loading of shoulder flexion (FLX) and extension (EXT) in the sagittal plane (ROM: 20- 180°; concentric mode; 180°/s) until individual peak torque was reduced by 50%. Simultaneously 3D scapular kinematics were assessed with a motion capture system and scapular muscle activity with a 3-lead sEMG of upper and lower trapezius (UT, LT) and serratus anterior (SA). Scapular position angles were calculated for every 20° increment between 20-120° humerothoracic positions. Muscle activity was quantified by amplitudes (RMS) of the total ROM. Descriptive analyses (mean±SD) of kinematics and muscle activity at begin (taskB) and end (taskE) of the loading task was followed by ANOVA and paired t-tests. RESULTS: At taskB activity ranged from 589±343mV to 605±250mV during FLX and from 105±41mV to 164±73mV during EXT across muscles. At taskE activity ranged from 594±304mV to 875±276mV during FLX and from 97±33mV to 147±57mV during EXT. Differences with increased muscle activity were seen for LT and UT during FLX (meandiff= 141±113mV for LT, p<0.01; 191±153mV for UT, p<0.01). Scapula position angles continuously increased in upward rotation, posterior tilt and external rotation during FLX and reversed during EXT both at taskB and taskE. At taskE scapula showed greater external rotation (meandiff= 3.6±3.7°, p<0.05) during FLX and decreased upward rotation (meandiff= 1.9±2.3°, p<0.05) and posterior tilt (meandiff= 1.0±2.1°, p<0.05) during EXT across humeral positions. CONCLUSIONS: Force reduction in consequence of fatiguing shoulder loading results in increased scapular muscle activity and minor alterations in scapula motion. Whether even small changes have a clinical impact by creating unfavorable subacromial conditions potentially initiating pain remains unclear. Y1 - 2020 U6 - https://doi.org/10.1249/01.mss.0000676540.02017.2c SN - 0195-9131 SN - 1530-0315 VL - 52 IS - 17 SP - 274 EP - 274 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - JOUR A1 - Wochatz, Monique A1 - Schraplau, Anne A1 - Engel, Tilman A1 - Zecher, Mahli Megan A1 - Sharon, Hadar A1 - Alt, Yasmin A1 - Mayer, Frank A1 - Kalron, Alon T1 - Application of eccentric training in various clinical populations BT - Protocol for a multi-centered pilot and feasibility study in people with low back pain and people with multiple sclerosis JF - PLoS ONE N2 - Physical activity and exercise are effective approaches in prevention and therapy of multiple diseases. Although the specific characteristics of lengthening contractions have the potential to be beneficial in many clinical conditions, eccentric training is not commonly used in clinical populations with metabolic, orthopaedic, or neurologic conditions. The purpose of this pilot study is to investigate the feasibility, functional benefits, and systemic responses of an eccentric exercise program focused on the trunk and lower extremities in people with low back pain (LBP) and multiple sclerosis (MS). A six-week eccentric training program with three weekly sessions is performed by people with LBP and MS. The program consists of ten exercises addressing strength of the trunk and lower extremities. The study follows a four-group design (N = 12 per group) in two study centers (Israel and Germany): three groups perform the eccentric training program: A) control group (healthy, asymptomatic); B) people with LBP; C) people with MS; group D (people with MS) receives standard care physiotherapy. Baseline measurements are conducted before first training, post-measurement takes place after the last session both comprise blood sampling, self-reported questionnaires, mobility, balance, and strength testing. The feasibility of the eccentric training program will be evaluated using quantitative and qualitative measures related to the study process, compliance and adherence, safety, and overall program assessment. For preliminary assessment of potential intervention effects, surrogate parameters related to mobility, postural control, muscle strength and systemic effects are assessed. The presented study will add knowledge regarding safety, feasibility, and initial effects of eccentric training in people with orthopaedic and neurological conditions. The simple exercises, that are easily modifiable in complexity and intensity, are likely beneficial to other populations. Thus, multiple applications and implementation pathways for the herein presented training program are conceivable. Y1 - 2022 U6 - https://doi.org/10.1371/journal.pone.0270875 SN - 1932-6203 VL - 17 IS - 12 PB - Public Library of Science CY - San Francisco, California, USA ER - TY - JOUR A1 - Henschke, Jakob A1 - Kaplick, Hannes A1 - Wochatz, Monique A1 - Engel, Tilman T1 - Assessing the validity of inertial measurement units for shoulder kinematics using a commercial sensor-software system BT - a validation study JF - Health science reports N2 - Background and Aims Wearable inertial sensors may offer additional kinematic parameters of the shoulder compared to traditional instruments such as goniometers when elaborate and time-consuming data processing procedures are undertaken. However, in clinical practice simple-real time motion analysis is required to improve clinical reasoning. Therefore, the aim was to assess the criterion validity between a portable "off-the-shelf" sensor-software system (IMU) and optical motion (Mocap) for measuring kinematic parameters during active shoulder movements. Methods 24 healthy participants (9 female, 15 male, age 29 +/- 4 years, height 177 +/- 11 cm, weight 73 +/- 14 kg) were included. Range of motion (ROM), total range of motion (TROM), peak and mean angular velocity of both systems were assessed during simple (abduction/adduction, horizontal flexion/horizontal extension, vertical flexion/extension, and external/internal rotation) and complex shoulder movements. Criterion validity was determined using intraclass-correlation coefficients (ICC), root mean square error (RMSE) and Bland and Altmann analysis (bias; upper and lower limits of agreement). Results ROM and TROM analysis revealed inconsistent validity during simple (ICC: 0.040-0.733, RMSE: 9.7 degrees-20.3 degrees, bias: 1.2 degrees-50.7 degrees) and insufficient agreement during complex shoulder movements (ICC: 0.104-0.453, RMSE: 10.1 degrees-23.3 degrees, bias: 1.0 degrees-55.9 degrees). Peak angular velocity (ICC: 0.202-0.865, RMSE: 14.6 degrees/s-26.7 degrees/s, bias: 10.2 degrees/s-29.9 degrees/s) and mean angular velocity (ICC: 0.019-0.786, RMSE:6.1 degrees/s-34.2 degrees/s, bias: 1.6 degrees/s-27.8 degrees/s) were inconsistent. Conclusions The "off-the-shelf" sensor-software system showed overall insufficient agreement with the gold standard. Further development of commercial IMU-software-solutions may increase measurement accuracy and permit their integration into everyday clinical practice. KW - diagnostic techniques and procedures KW - kinematics KW - shoulder joint KW - validation study KW - wearable devices Y1 - 2022 U6 - https://doi.org/10.1002/hsr2.772 SN - 2398-8835 VL - 5 IS - 5 SP - 1 EP - 11 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Scharhag-Rosenberger, Friederike A1 - Wochatz, Monique A1 - Otto, Christoph A1 - Cassel, Michael A1 - Mayer, Frank A1 - Scharhag, Jürgen T1 - Blood lactate concentrations are mildly affected by mobile gas exchange measurements JF - International journal of sports medicine N2 - We sought to investigate the effects of wearing a mobile respiratory gas analysis system during a treadmill test on blood lactate (bLa) concentrations and commonly applied bLa thresholds. A total of 16 recreational athletes (31 +/- 3 years, V0205: 58 6 ml min(-1)-kg(-1)) performed one multistage treadmill test with and one without gas exchange measurements (GEM and noGEM). The whole bLa curve, the lactate threshold (LT), the individual anaerobic thresholds according to Stegmann(IAT(sr)) and Dickhuth (IAT(Di)), and a fixed bLa concentration of 4 mmob.l(-1) (OBLA) were evaluated. The bLa curve was shifted slightly leftward in GEM compared to noGEM (P<0.05), whereas the heart rate response was not different between conditions (P= 0.89). There was no difference between GEM and noGEM for LT (2.61 +/- 0.34 vs. 2.64 +/- 0.39 m(-1) s(-1) P=0.49) and IAT(st) (3.47 +/- 0.42 vs. 3.55 +/- 0.47m-s(-1), P=0.12). However, IATD(Di) (3.57 +/- 0.39 vs. 3.66 +/- 0.44m-s(-1), P<0.01) and OBLA (3.85 +/- 0.46 vs. 3.96 +/- 0.47m-s-1, P<0.01) occurred at slower running velocities in GEM. The bLa response to treadmill tests is mildly affected by wearing a mobile gas analysis system. This also applies to bLa thresholds located at higher exercise intensities. While the magnitude of the effects is of little importance for recreational athletes, it might be relevant for elite athletes and scientific studies. KW - cardiopulmonary exercise testing KW - performance diagnostics KW - lactate threshold KW - VO2mdx KW - metabolic device Y1 - 2014 U6 - https://doi.org/10.1055/s-0033-1354386 SN - 0172-4622 SN - 1439-3964 VL - 35 IS - 7 SP - 590 EP - 594 PB - Thieme CY - Stuttgart ER - TY - GEN A1 - Schomöller, Anne A1 - Risch, Lucie A1 - Kaplick, Hannes A1 - Schraplau, Anne A1 - Wochatz, Monique A1 - Engel, Tilman A1 - Sonnenburg, Dominik A1 - Mayer, Frank T1 - Changes in paraspinal muscle T2 times and creatine kinase after a bout of eccentric exercise T2 - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine N2 - Eccentric (ECC) exercises might cause muscle damage, characterized by delayed-onset muscle soreness, elevated creatine kinase (CK) levels and local muscle oedema, shown by elevated T2 times in magnet resonance imaging (MRI) scans. Previous research suggests a high inter-individual difference regarding these systemic and local responses to eccentric workload. PURPOSE: To analyze ECC exercise-induced muscle damage in lumbar paraspinal muscles assessed via MRI. METHODS: Ten participants (3f/7m; 33±6y; 174±8cm; 71±12kg) were included in the study. Quantitative paraspinal muscle constitution of M. erector spinae and M. multifidius were assessed in supine position before and 72h after an intense eccentric trunk exercise bout in a mobile 1.5 tesla MRI device. MRI scans were recorded on spinal level L3 (T2-weighted TSE echo sequences, 11 slices, 2mm slice thickness, 3mm gap, echo times: 20, 40, 60, 80, 100ms, TR time: 2500ms). Muscle T2 times were calculated for manually traced regions of interest of the respective muscles with an imaging software. The exercise protocol was performed in an isokinetic device and consisted of 120sec alternating ECC trunk flexion-extension with maximal effort. Venous blood samples were taken before and 72h after the ECC exercise. Descriptive statistics (mean±SD) and t-testing for pre-post ECC exercises were performed. RESULTS: T2 times increased from pre- to post-ECC MRI measurements from 55±3ms to 79±28ms in M. erector spinae and from 62±5ms to 78±24ms in M. multifidius (p<0.001). CK increased from 126±97 U/L to 1447±20579 U/L. High SDs of T2 time and CK in post-ECC measures could be due to inter-individual reactions to ECC exercises. 3 participants showed high local and systemic reactions (HR) with T2 time increases of 120±24% (M. erector spinae) and 73±50% (M. multifidius). In comparison, the remaining 7 participants showed increases of 11±12% (M. erector spinae) and 7±9% (M. multifidius) in T2 time. Mean CK increased 9.5-fold in the 3 HR subjects compared with the remaining 7 subjects. CONCLUSIONS: The 120sec maximal ECC trunk flexion-extension protocol induced high amounts of muscle damage in 3 participants. Moderate to low responses were found in the remaining 7 subjects, assuming that inter-individual predictors play a role regarding physiological responses to ECC workload. Y1 - 2020 U6 - https://doi.org/10.1249/01.mss.0000685648.68626.f1 SN - 0195-9131 SN - 1530-0315 SN - 0025-7990 VL - 52 IS - 17 SP - 929 EP - 929 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - GEN A1 - Schraplau, Anne A1 - Sonnenburg, Dominik A1 - Wochatz, Monique A1 - Engel, Tilman A1 - Schomöller, Anne A1 - Risch, Lucie A1 - Kaplick, Hannes A1 - Mayer, Frank T1 - Characterization of muscle damage and inflammation following repeated maximal eccentric loading of the trunk T2 - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine N2 - Eccentric exercises (ECC) induce reversible muscle damage, delayed-onset muscle soreness and an inflammatory reaction that is often followed by a systemic anti-inflammatory response. Thus, ECC might be beneficial for treatment of metabolic disorders which are frequently accompanied by a low-grade systemic inflammation. However, extent and time course of a systemic immune response after repeated ECC bouts are poorly characterized. PURPOSE: To analyze the (anti-)inflammatory response after repeated ECC loading of the trunk. METHODS: Ten healthy participants (33 ± 6 y; 173 ± 14 cm; 74 ± 16 kg) performed three isokinetic strength measurements of the trunk (concentric (CON), ECC1, ECC2, each 2 wks apart; flexion/extension, velocity 60°/s, 120s MVC). Pre- and 4, 24, 48, 72, 168h post-exercise, muscle soreness (numeric rating scale, NRS) was assessed and blood samples were taken and analyzed [Creatine kinase (CK), C-reactive protein (CRP), Interleukin-6 (IL-6), IL-10, Tumor necrosis factor-α (TNF-α)]. Statistics were done by Friedman‘s test with Dunn‘s post hoc test (α=.05). RESULTS: Mean peak torque was higher during ECC1 (319 ± 142 Nm) than during CON (268 ± 108 Nm; p<.05) and not different between ECC1 and ECC2 (297 ± 126 Nm; p>.05). Markers of muscle damage (peaks post-ECC1: NRS 48h, 4.4±2.9; CK 72h, 14407 ± 19991 U/l) were higher after ECC1 than after CON and ECC2 (p<.05). The responses over 72h (stated as Area under the Curve, AUC) were abolished after ECC2 compared to ECC1 (p<.05) indicating the presence of the repeated bout effect. CRP levels were not changed. IL-6 levels increased 2-fold post-ECC1 (pre: 0.5 ± 0.4 vs. 72h: 1.0 ± 0.8 pg/ml). The IL-6 response was enhanced after ECC1 (AUC 61 ± 37 pg/ml*72h) compared to CON (AUC 33 ± 31 pg/ml*72h; p<.05). After ECC2, the IL-6 response (AUC 43 ± 25 pg/ml*72h) remained lower than post-ECC1, but the difference was not statistically significant. Serum levels of TNF-α and of the anti-inflammatory cytokine IL-10 were below detection limits. Overall, markers of muscle damage and immune response showed high inter-individual variability. CONCLUSION: Despite maximal ECC loading of a large muscle group, no anti-inflammatory and just weak inflammatory responses were detected in healthy adults. Whether ECC elicits a different reaction in inflammatory clinical conditions is unclear. Y1 - 2020 U6 - https://doi.org/10.1249/01.mss.0000679532.65880.af SN - 0195-9131 SN - 1530-0315 VL - 52 IS - 7S SP - 497 EP - 497 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - JOUR A1 - Khajooei, Mina A1 - Wochatz, Monique A1 - Baritello, Omar A1 - Mayer, Frank T1 - Effects of shoes on children’s fundamental motor skills performance JF - Footwear science : official journal of the Footwear Biomechanics Group N2 - Progression or impediment of fundamental motor skills performance (FMSP) in children depends on internal and environmental factors. Shoes as an environmental constraint are believed to affect these movements as children showed to perform qualitatively better with sports shoes than flip-flop sandals. However, locomotor performance assessments based on biomechanical variables are limited. Therefore, the objective of this experiment was to assess the biomechanical effects of wearing shoes while performing fundamental motor skills in children. Barefoot and shod conditions were tested in healthy children between the age of 4 and 7 years. They were asked to perform basic and advanced motor skills including double-leg stance, horizontal jumps, walking as well as counter-movement jumps, single-leg stance and sprinting. Postural control and ground reaction data were measured with two embedded force plates. A 3D motion capture system was used to analyse the spatiotemporal parameters of walking and sprinting. Findings showed that the parameters of single- and double-leg stance, horizontal and counter-movement jump did not differ between barefoot and shod conditions. Most of the spatiotemporal variables including cadence, stride length, stride time, and contact time of walking and sprinting were statistically different between the barefoot and shod conditions. Consequently, tested shoes did not change performance and biomechanics of postural control and jumping tasks; however, the spatiotemporal gait parameters indicate changes in walking and sprinting characteristics with shoes in children. KW - Spatiotemporal KW - kinetics KW - jumping KW - stability KW - gait Y1 - 2019 U6 - https://doi.org/10.1080/19424280.2019.1696895 SN - 1942-4280 SN - 1942-4299 VL - 12 IS - 1 SP - 55 EP - 62 PB - Taylor & Francis CY - Abingdon ER - TY - JOUR A1 - Engel, Tilman A1 - Schraplau, Anne A1 - Wochatz, Monique A1 - Kopinski, Stephan A1 - Sonnenburg, Dominik A1 - Schomöller, Anne A1 - Risch, Lucie A1 - Kaplick, Hannes A1 - Mayer, Frank T1 - Feasability of An Eccentric Isokinetic Protocol to Induce Trunk Muscle Damage: A Pilot Study JF - Sports Medicine International Open N2 - Eccentric exercise is discussed as a treatment option for clinical populations, but specific responses in terms of muscle damage and systemic inflammation after repeated loading of large muscle groups have not been conclusively characterized. Therefore, this study tested the feasibility of an isokinetic protocol for repeated maximum eccentric loading of the trunk muscles. Nine asymptomatic participants (5 f/4 m; 34±6 yrs; 175±13 cm; 76±17 kg) performed three isokinetic 2-minute all-out trunk strength tests (1x concentric (CON), 2x eccentric (ECC1, ECC2), 2 weeks apart; flexion/extension, 60°/s, ROM 55°). Outcomes were peak torque, torque decline, total work, and indicators of muscle damage and inflammation (over 168 h). Statistics were done using the Friedman test (Dunn’s post-test). For ECC1 and ECC2, peak torque and total work were increased and torque decline reduced compared to CON. Repeated ECC bouts yielded unaltered torque and work outcomes. Muscle damage markers were highest after ECC1 (soreness 48 h, creatine kinase 72 h; p<0.05). Their overall responses (area under the curve) were abolished post-ECC2 compared to post-ECC1 (p<0.05). Interleukin-6 was higher post-ECC1 than CON, and attenuated post-ECC2 (p>0.05). Interleukin-10 and tumor necrosis factor-α were not detectable. All markers showed high inter-individual variability. The protocol was feasible to induce muscle damage indicators after exercising a large muscle group, but the pilot results indicated only weak systemic inflammatory responses in asymptomatic adults. KW - exercise KW - eccentric KW - muscle fatigue KW - trunk muscles KW - isokinetics KW - repeated bout effect KW - inflammation KW - exercise induced muscle damage KW - interleukin-6 KW - internleukin-10 KW - tumor necrosis factor-α Y1 - 2021 U6 - https://doi.org/10.1055/a-1757-6724 SN - 2367-1890 VL - 6 SP - E9 EP - E17 PB - Thieme CY - Stuttgart ET - 1 ER - TY - CHAP A1 - Wochatz, Monique A1 - Kopinski, Stephan A1 - Engel, Tilman A1 - Müller, Steffen A1 - Mayer, Frank T1 - Flexion-extension ratio of trunk peak torque measures and antagonistic activity in males and females 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 - 148 EP - 148 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - THES A1 - Wochatz, Monique T1 - Influence of different loading conditions on scapular movement and scapular muscle activation patterns T1 - Der Einfluss verschiedener Lastsituationen auf Bewegungs- und Aktivitätsmuster des Schulterblatts N2 - The scapula plays a significant role in efficient shoulder movement. Thus, alterations from typical scapular motion during upper limb movements are thought to be associated with shoulder pathologies. However, a clear understanding of the relationship is not yet obtained.. Scapular alterations may only represent physiological variability as their occurrence can appear equally as frequent in individuals with and without shoulder disorders. Evaluation of scapular motion during increased load might be a beneficial approach to detect clinically relevant alterations. However, functional motion adaptations in response to maximum effort upper extremity loading has not been established yet. Therefore, the overall purpose of this research project was to give further insight in physiological adaptations of scapular kinematics and their underlying scapular muscle activity in response to high demanding shoulder movements in healthy asymptomatic individuals. Prior to the investigation of the effect of various load situation, the reproducibility of scapular kinematics and scapular muscle activity were evaluated under maximum effort arm movements. Healthy asymptomatic adults performed unloaded and maximal loaded concentric and eccentric isokinetic shoulder flexion and extension movements in the scapular plane while scapular kinematics and scapular muscle activity were simultaneously assessed. A 3D motion capture system (infra-red cameras & reflective markers) was utilized to track scapular and humerus motion in relation to the thorax. 3D scapular position angles were given for arm raising and lowering between humerus positions of 20° and 120° flexion. To further characterize the scapular pattern, the scapular motion extent and scapulohumeral rhythm (ratio of scapular and humerus motion extent) were determined. Muscle activity of the upper and lower trapezius and the serratus anterior were assessed with surface electromyography. Amplitudes were calculated for the whole ROM and four equidistant movement phases. Reliability was characterized by overall moderate to good reproducibility across the load conditions. Irrespective of applied load, scapular kinematics followed a motion pattern of continuous upward rotation, posterior tilt and external rotation during arm elevation and a continuous downward rotation, anterior tilt and internal rotation during arm lowering. However, kinematics were altered between maximal loaded and unloaded conditions showing increased upward rotation, reduced posterior tilt and external rotation. Further, the scapulohumeral rhythm was decreased and scapular motion extent increased under maximal loaded movements. Muscle activity during maximum effort were of greater magnitude and differed in their pattern in comparison to the continuous increase and decrease of activity during unloaded shoulder flexion and extension. Relationships between scapular kinematics and their underlying scapular muscle activity could only be identified for a few isolated combinations, whereas the majority showed no associations. Scapular kinematics and scapular muscle activity pattern alter according to the applied load. Alterations between the load conditions comply in magnitude and partially in direction with differences seen between symptomatic and asymptomatic individuals. Even though long-term effects of identified adaptations in response to maximum load are so far unclear, deviations from typical scapular motion or muscle activation should not per se be seen as indicators of shoulder impairment. However, evaluation of alterations in scapular motion and activation in response to maximum effort may have the potential to identify individuals that are unable to cope with increased upper limb demands. Findings further challenge the understanding of scapular motion and stabilization by the trapezius and serratus anterior muscles, as clear relationships between the underlying scapular muscle activity and scapular kinematics were neither observed during unloaded nor maximal loaded shoulder movements. N2 - Das Schulterblatt ist entscheidend für die uneingeschränkte Bewegung und Positionierung der oberen Extremität. Atypische Bewegungsmuster des Schulterblatts werden deshalb oft mit Schulterpathologien in Verbindung gebracht, obwohl die zugrundeliegenden Mechanismen noch nicht ausreichend geklärt sind. Abweichungen stellen möglicherweise nur eine Form physiologischer Variabilität dar, da Veränderungen der Schulterblattbewegung sowohl bei Personen mit als auch ohne Schulterbeschwerden auftreten können. Die Beurteilung der Schulterblattbewegung unter erhöhten Lastbedingungen könnte hilfreich bei der Differenzierung von funktionellen und klinisch relevanten Veränderungen sein. Jedoch sind physiologische Anpassungen der Schulterblattkinematik in Reaktion auf maximale Anforderungen während einer Bewegungsaufgabe der oberen Extremität bisher nicht untersucht. Das Ziel dieses Forschungsprojektes war es deshalb weitere Erkenntnisse hinsichtlich physiologischer Anpassungen der Schulterblattkinematik und ihrer zugrundeliegenden Muskelaktivität zu erlangen. Bevor die Effekte verschiedener Belastungssituationen untersucht wurden, erfolgte die Beurteilung der Reproduzierbarkeit der Schulterblattkinematik sowie der Aktivitätslevel schulterblattstabilisierender Muskeln unter maximaler Anstrengung. Gesunde asymptomatische Erwachsene führten isokinetische Schulterbewegungen in Flexion und Extension unter unbelasteten sowie maximal belasteten Bedingungen durch. Zeitgleich wurde die Schulterblattkinematik sowie die Aktivität schulterstabilisierender Muskeln erfasst. Mit Hilfe eines 3D Kamera Systems (Infrarotkameras & reflektierende Marker) wurden Winkelpositionen des Schulterblatts für Humerus-Positionen zwischen 20° und 120° Flexion bestimmt. Zur weiteren Charakterisierung der Schulterblattbewegung wurde das Ausmaß der Schulterblattrotation sowie der skapulohumerale Rhythmus (Verhältnis von Schulterblatt- und Humerus-Bewegung) ermittelt. Während der Schulterbewegungen wurde die Muskelaktivität des oberen und unteren Trapezius sowie des Serratus anterior mit Oberflächen-Elektromyographie erfasst. Aktivitätslevel wurden für das gesamte Bewegungsausmaß sowie für einzelne Bewegungsphasen berechnet. Eine moderate bis gute Reproduzierbarkeit der Winkelpositionen des Schulterblatts sowie der Aktivitätslevel der schulterblattstabilisierenden Muskulatur konnte unter den verschiedenen Lastbedingungen erreicht werden. Unabhängig von der applizierten Last folgte das Schulterblatt einer kontinuierlichen Aufwärtsrotation, Rückwärtsneigung und Außenrotation während der Schulterflexion und einer kontinuierlichen Abwärtsrotation, Vorwärtsneigung und Innenrotation während der Schulterextension. Bei maximalen Belastungen zeigte das Schulterblatt jedoch eine gesteigerte Aufwärtsrotation sowie eine verringerte Rückwärtsneigung und Außenrotation im Vergleich zur unbelasteten Schulterbewegung. Der skapulohumerale Rhythmus verringerte sich und auch das Ausmaß der Schulterblattrotation war unter maximaler Last erhöht. Die Muskelaktivität zeigte sich unter maximaler Anstrengung nicht nur im Ausmaß gesteigert sondern wies auch ein verändertes Aktivitätsmuster im Verlauf der Bewegungen im Vergleich zur kontinuierlichen Zu- und Abnahme der Aktivität während unbelasteter Bedingungen auf. Korrelationen zwischen dem Ausmaß der Schulterblattrotation und dem Aktivitätslevel der Schulterblattmuskulatur konnten nur für einige wenige isolierte Kombinationen identifiziert werden, während die Mehrheit keine Assoziationen zeigte. Die Kinematik des Schulterblatts und die Aktivitätsmuster der Schulterblattmuskulatur ändern sich in Abhängigkeit der Belastung. Veränderungen der Kinematik und Aktivitätsmuster entsprechen dabei im Ausmaß und teilweise in der Ausrichtung den bekannten Unterschieden zwischen symptomatischen und asymptomatischen Populationen. Obwohl die langfristigen Auswirkungen dieser veränderten Schulterblattkinematik unter maximalen Belastungen bislang unklar sind, sollten Abweichungen von der typischen Bewegung des Schulterblatts sowie bekannter Aktivitätsmuster per se nicht als Indikatoren für eine Beeinträchtigung der Schulterfunktion angesehen werden. Dennoch könnten Untersuchungen der Schulterblattkinematik sowie der Aktivität schulterblattrotierender und –stabilisierender Muskeln unter erhöhten Anforderungen Personen identifizieren die aufgrund mangelnder Anpassung die gesteigerten Lasten nicht kompensieren können. Ein klares Zusammenspiel von Schulterblattkinematik und rotierender sowie stabilisierender Schulterblattmuskulatur ließ sich weder unter unbelasteten noch maximal belasteten Bedingungen aufzeigen. KW - scapular kinematics KW - 3D motion analysis KW - scapular muscles KW - electromyography KW - Schulterblattkinematik KW - 3D-Bewegungsanalyse KW - Schulterblattmuskulatur KW - Elektromyografie Y1 - 2021 ER -