@misc{WochatzSchraplauEngeletal.2022, author = {Wochatz, Monique and Schraplau, Anne and Engel, Tilman and Zecher, Mahli Megan and Sharon, Hadar and Alt, Yasmin and Mayer, Frank and Kalron, Alon}, title = {Application of eccentric training in various clinical populations}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {833}, issn = {1866-8364}, doi = {10.25932/publishup-58849}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-588493}, pages = {15}, year = {2022}, abstract = {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.}, language = {en} } @article{WochatzSchraplauEngeletal.2022, author = {Wochatz, Monique and Schraplau, Anne and Engel, Tilman and Zecher, Mahli Megan and Sharon, Hadar and Alt, Yasmin and Mayer, Frank and Kalron, Alon}, title = {Application of eccentric training in various clinical populations}, series = {PLoS ONE}, volume = {17}, journal = {PLoS ONE}, number = {12}, publisher = {Public Library of Science}, address = {San Francisco, California, USA}, issn = {1932-6203}, doi = {10.1371/journal.pone.0270875}, pages = {15}, year = {2022}, abstract = {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.}, language = {en} } @article{WochatzRabeWolteretal.2017, author = {Wochatz, Monique and Rabe, Sophie and Wolter, Martin and Engel, Tilman and Mueller, Steffen and Mayer, Frank}, title = {Reproducibility of scapular muscle activity in isokinetic shoulder flexion and extension}, series = {Journal of electromyography and kinesiology}, volume = {34}, journal = {Journal of electromyography and kinesiology}, publisher = {Elsevier}, address = {Oxford}, issn = {1050-6411}, doi = {10.1016/j.jelekin.2017.04.006}, pages = {86 -- 92}, year = {2017}, abstract = {Repetitive overhead movements have been identified as a main risk factor to develop shoulder complaints with scapular muscle activity being altered. Reliable assessment of muscle activity is essential to differentiate between symptomatic and asymptomatic individuals. Therefore, the present study aimed to investigate the intra-and inter-session reliability of scapular muscle activity during maximal isokinetic shoulder flexion and extension. Eleven asymptomatic adults performed maximum effort isokinetic shoulder flexion and extension (concentric and eccentric at 60 degrees/s) in a test-retest design. Muscle activity of the upper and lower trapezius and serratus anterior was assessed by sEMG. Root Mean Square was calculated for whole ROM and single movement phases of absolute and normalized muscle activity. Absolute (Bland-Altman analysis (Bias, LoA), Minimal detectable change (MDC)) and relative reliability parameters (Intraclass correlation coefficient (ICC), coefficient of variation (CV)/test-retest variability (TRV)) were utilized for the evaluation of reproducibility. Intra-session reliability revealed ICCs between 0.56 and 0.98, averaged CVs of 18\% and average MDCs of 81 mV. Inter-session reliability resulted in ICCs between 0.13 and 0.93, averaged TRVs of 21\%, average MDCs of 15\% and systematic and random error between -8 +/- 60\% and 12 +/- 36\%. Scapular muscle activity assessed in overhead movements can be measured reliably under maximum load conditions, though variability is dependent on the movement phase. Measurement variability does not exceed magnitudes of altered scapular muscle activities as reported in previous studies. Therefore, maximum load application is a promising approach for the evaluation of changes in scapular control related to pathologies. (C) 2017 Elsevier Ltd. All rights reserved.}, language = {en} } @article{WochatzRabeWolteretal.2017, author = {Wochatz, Monique and Rabe, Sophie and Wolter, Martin and Engel, Tilman and Mueller, Steffen and Mayer, Frank}, title = {Muscle activity of upper and lower trapezius and serratus anterior during unloaded and maximal loaded shoulder flexion and extension}, series = {International Biomechanics}, volume = {4}, journal = {International Biomechanics}, number = {2}, publisher = {Elsevier}, address = {Amsterdam}, doi = {https://doi.org/10.1080/23335432.2017.1364668}, pages = {68 -- 76}, year = {2017}, abstract = {Altered scapular muscle activity is mostly described under unloaded and submaximal loaded conditions in impingement patients. However, there is no clear evidence on muscle activity with respect to movement phases under maximum load in healthy subjects. Therefore, this study aimed to investigate scapular muscle activity under unloaded and maximum loaded isokinetic shoulder flexion and extension in regard to the movement phase. Fourteen adults performed unloaded (continuous passive motion [CPM]) as well as maximum loaded (concentric [CON], eccentric [ECC]) isokinetic shoulder flexion (Flex) and extension (Ext). Simultaneously, scapular muscle activity was measured by EMG. Root mean square was calculated for the whole ROM and four movement phases. Data were analyzed descriptively and by two-way repeated measures ANOVA. CPMFlex resulted in a linear increase of muscle activity for all muscles. Muscle activity during CONFlex and ECCFlex resulted in either constant activity levels or in an initial increase followed by a plateau in the second half of movement. CPMExt decreased with the progression of movement, whereas CONExt and ECCExt initially decreased and either levelled off or increased in the second half of movement. Scapular muscle activity of unloaded shoulder flexion and extension changed under maximum load showing increased activity levels and an altered pattern over the course of movement.}, language = {en} } @article{WochatzRabeEngeletal.2021, author = {Wochatz, Monique and Rabe, Sophie and Engel, Tilman and M{\"u}ller, Steffen and Mayer, Frank}, title = {Scapular kinematics during unloaded and maximal loaded isokinetic concentric and eccentric shoulder flexion and extension movements}, series = {Journal of electromyography \& kinesiology : official journal of the International Society of Electrophysiology and Kinesiology}, volume = {57}, journal = {Journal of electromyography \& kinesiology : official journal of the International Society of Electrophysiology and Kinesiology}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1050-6411}, doi = {10.1016/j.jelekin.2021.102517}, pages = {8}, year = {2021}, abstract = {Characterization of scapular kinematics under demanding load conditions might aid to distinguish between physiological and clinically relevant alterations. Previous investigations focused only on submaximal external load situations. How scapular movement changes with maximal load remains unclear. Therefore, the present study aimed to evaluate 3D scapular kinematics during unloaded and maximal loaded shoulder flexion and extension. Twelve asymptomatic individuals performed shoulder flexion and extension movements under unloaded and maximal concentric and eccentric loaded isokinetic conditions. 3D scapular kinematics assessed with a motion capture system was analyzed for 20° intervals of humeral positions from 20° to 120° flexion. Repeated measures ANOVAs were used to evaluate kinematic differences between load conditions for scapular position angles, scapulohumeral rhythm and scapular motion extent. Increased scapular upward rotation was seen during shoulder flexion and extension as well as decreased posterior tilt and external rotation during eccentric and concentric arm descents of maximal loaded compared to unloaded conditions. Load effects were further seen for the scapulohumeral rhythm with greater scapular involvement at lower humeral positions and increased scapular motion extent under maximal loaded shoulder movements. With maximal load applied to the arm physiological scapular movement pattern are induced that may imply both impingement sparing and causing mechanisms.}, language = {en} } @inproceedings{WochatzKopinskiEngeletal.2014, author = {Wochatz, Monique and Kopinski, Stephan and Engel, Tilman and M{\"u}ller, Steffen and Mayer, Frank}, title = {Flexion-extension ratio of trunk peak torque measures and antagonistic activity in males and females}, 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 = {148 -- 148}, year = {2014}, language = {en} } @article{WochatzEngelMuelleretal.2020, author = {Wochatz, Monique and Engel, Tilman and M{\"u}ller, Steffen and Mayer, Frank}, title = {Alterations in scapular kinematics and scapular muscle activity after fatiguing shoulder flexion and extension movements}, series = {Medicine and science in sports and exercise : MSSE}, volume = {52}, journal = {Medicine and science in sports and exercise : MSSE}, number = {17}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {0195-9131}, doi = {10.1249/01.mss.0000676540.02017.2c}, pages = {274 -- 274}, year = {2020}, abstract = {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.}, 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{SchraplauSonnenburgWochatzetal.2020, author = {Schraplau, Anne and Sonnenburg, Dominik and Wochatz, Monique and Engel, Tilman and Schom{\"o}ller, Anne and Risch, Lucie and Kaplick, Hannes and Mayer, Frank}, title = {Characterization of muscle damage and inflammation following repeated maximal eccentric loading of the trunk}, series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine}, volume = {52}, journal = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine}, number = {7S}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {0195-9131}, doi = {10.1249/01.mss.0000679532.65880.af}, pages = {497 -- 497}, year = {2020}, abstract = {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.}, language = {en} } @article{SchomoellerRischKaplicketal.2021, author = {Schom{\"o}ller, Anne and Risch, Lucie and Kaplick, Hannes and Wochatz, Monique and Engel, Tilman and Schraplau, Anne and Sonnenburg, Dominik and Huppertz, Alexander and Mayer, Frank}, title = {Inter-rater and inter-session reliability of lumbar paraspinal muscle composition in a mobile MRI device}, series = {BJR : an international journal of radiology, radiation oncology and all related sciences / British Institute of Radiology}, volume = {94}, journal = {BJR : an international journal of radiology, radiation oncology and all related sciences / British Institute of Radiology}, number = {1127}, publisher = {Wiley}, address = {Bognor Regis}, issn = {0007-1285}, doi = {10.1259/bjr.20210141}, pages = {6}, year = {2021}, abstract = {Objective: To assess the reliability of measurements of paraspinal muscle transverse relaxation times (T2 times) between two observers and within one observer on different time points.
Methods: 14 participants (9f/5m, 33 +/- 5 years, 176 +/- 10 cm, 73 +/- 12 kg) underwent 2 consecutive MRI scans (M1,M2) on the same day, followed by 1 MRI scan 13-14 days later (M3) in a mobile 1.5 Tesla MRI. T2 times were calculated in T-2 weighted turbo spin- echo-sequences at the spinal level of the third lumbar vertebrae (11 slices, 2 mm slice thickness, 1 mm interslice gap, echo times: 20, 40, 60, 80, 100 ms) for M. erector spinae (ES) and M. multifidius (MF). The following reliability parameter were calculated for the agreement of T2 times between two different investigators (OBS1 \& OBS2) on the same MRI (inter rater reliability, IR) and by one investigator between different MRI of the same participant (intersession variability, IS): Test-Retest Variability (TRV, Differences/Mean*100); Coefficient of Variation (CV, Standard deviation/Mean*100); Bland-Altman Analysis (systematic bias = Mean of the Differences; Upper/Lower Limits of Agreement = Bias+/-1.96*SD); Intraclass Correlation Coefficient 3.1 (ICC) with absolute agreement, as well as its 95\% confidence interval.
Results: Mean TRV for IR was 2.6\% for ES and 4.2\% for MF. Mean TRV for IS was 3.5\% (ES) and 5.1\% (MF). Mean CV for IR was 1.9 (ES) and 3.0 (MF). Mean CV for IS was 2.5\% (ES) and 3.6\% (MF). A systematic bias of 1.3 ms (ES) and 2.1 ms (MF) were detected for IR and a systematic bias of 0.4 ms (ES) and 0.07 ms (MF) for IS. ICC for IR was 0.94 (ES) and 0.87 (MF). ICC for IS was 0.88 (ES) and 0.82 (MF).
Conclusion: Reliable assessment of paraspinal muscle T2 time justifies its use for scientific purposes. The applied technique could be recommended to use for future studies that aim to assess changes of T2 times, e.g. after an intense bout of eccentric exercises.}, language = {en} } @misc{SchomoellerRischKaplicketal.2020, author = {Schom{\"o}ller, Anne and Risch, Lucie and Kaplick, Hannes and Schraplau, Anne and Wochatz, Monique and Engel, Tilman and Sonnenburg, Dominik and Mayer, Frank}, title = {Changes in paraspinal muscle T2 times and creatine kinase after a bout of eccentric exercise}, series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine}, volume = {52}, journal = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine}, number = {17}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {0195-9131}, doi = {10.1249/01.mss.0000685648.68626.f1}, pages = {929 -- 929}, year = {2020}, abstract = {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.}, language = {en} } @article{RowleyEngelKulig2020, author = {Rowley, K. Michael and Engel, Tilman and Kulig, Kornelia}, title = {Trunk and hip muscle activity during the Balance-Dexterity task in persons with and without recurrent low back pain}, series = {Journal of electromyography and kinesiology}, volume = {50}, journal = {Journal of electromyography and kinesiology}, publisher = {Elsevier Science}, address = {Amsterdam}, issn = {1050-6411}, doi = {10.1016/j.jelekin.2019.102378}, pages = {7}, year = {2020}, abstract = {Coordination of the trunk and hips is crucial for successful dynamic balance in many activities of daily living. Persons with recurrent low back pain (rLBP), both while symptomatic and during periods of symptom remission, exhibit dysfunctional muscle activation patterns and coordination of these joints. In a novel dynamic balance task where persons in remission from rLBP exhibit dissociated trunk motion, it is unknown how trunk and hip musculature are coordinated. Activation of hip and trunk muscles were acquired from nineteen persons with and without rLBP during the Balance-Dexterity Task, which involves balancing on one limb while compressing an unstable spring with the other. There were no between-group differences in activation amplitude for any muscle groups tested. In back-healthy control participants, hip and trunk muscle activation amplitudes increased proportionally in response to the added instability of the spring (R = 0.837, p < 0.001). Increases in muscle activation amplitudes in the group in remission from rLBP were not proportional (R = 0.113, p = 0.655). Instead, hip muscle activation in this group was associated with task performance, i.e. dexterous control of the spring (R = 0.676, p = 0.002). These findings highlight atypical coordination of hip and trunk musculature potentially related to task demands in persons with rLBP even during remission from pain.}, language = {en} } @article{RischWochatzMesserschmidtetal.2017, author = {Risch, Lucie and Wochatz, Monique and Messerschmidt, Janin and Engel, Tilman and Mayer, Frank and Cassel, Michael}, title = {Reliability of evaluating achilles tendon vascularization assessed with doppler ultrasound advanced dynamic flow}, series = {Journal of ultrasound in medicine}, volume = {37}, journal = {Journal of ultrasound in medicine}, number = {3}, publisher = {Wiley}, address = {Hoboken}, issn = {0278-4297}, doi = {10.1002/jum.14414}, pages = {737 -- 744}, year = {2017}, abstract = {The reliability of quantifying intratendinous vascularization by high-sensitivity Doppler ultrasound advanced dynamic flow has not been examined yet. Therefore, this study aimed to investigate the intraobserver and interobserver reliability of evaluating Achilles tendon vascularization by advanced dynamic flow using established scoring systems. Methods-Three investigators evaluated vascularization in 67 recordings in a test-retest design, applying the Ohberg score, a modified Ohberg score, and a counting score. Intraobserver and interobserver agreement for the Ohberg score and modified Ohberg score was analyzed by the Cohen kappa and Fleiss kappa coefficients (absolute), Kendall tau b coefficient, and Kendall coefficient of concordance (W; relative). The reliability of the counting score was analyzed by intraclass correlation coefficients (ICC) 2.1 and 3.1, the standard error of measurement (SEM), and Bland-Altman analysis (bias and limits of agreement [LoA]). Results-Intraobserver and interobserver agreement (absolute/relative) ranged from 0.61 to 0.87/0.87 to 0.95 and 0.11 to 0.66/0.76 to 0.89 for the Ohberg score and from 0.81 to 0.87/0.92 to 0.95 and 0.64 to 0.80/0.88 to 0.93 for the modified Ohberg score, respectively. The counting score revealed an intraobserver ICC of 0.94 to 0.97 (SEM, 1.0-1.5; bias, -1; and LoA, 3-4 vessels). The interobserver ICC for the counting score ranged from 0.91 to 0.98 (SEM, 1.0-1.9; bias, 0; and LoA, 3-5 vessels). Conclusions-The modified Ohberg score and counting score showed excellent reliability and seem convenient for research and clinical practice. The Ohberg score revealed decent intraobserver but unexpected low interobserver reliability and therefore cannot be recommended.}, language = {en} } @article{RischStollSchomoelleretal.2020, author = {Risch, Lucie and Stoll, Josefine and Schom{\"o}ller, Anne and Engel, Tilman and Mayer, Frank and Cassel, Michael}, title = {Intraindividual Doppler Flow Response to Exercise Differs Between Symptomatic and Asymptomatic Achilles Tendons}, series = {Frontiers in physiology}, volume = {12}, journal = {Frontiers in physiology}, publisher = {Frontiers Research Foundation}, address = {Lausanne, Schweiz}, issn = {1664-042X}, doi = {10.3389/fphys.2021.617497}, pages = {1 -- 8}, year = {2020}, abstract = {Objective: This study investigated intraindividual differences of intratendinous blood flow (IBF) in response to running exercise in participants with Achilles tendinopathy. Design: This is a cross-sectional study. Setting: The study was conducted at the University Outpatient Clinic. Participants: Sonographic detectable intratendinous blood flow was examined in symptomatic and contralateral asymptomatic Achilles tendons of 19 participants (42 ± 13 years, 178 ± 10 cm, 76 ± 12 kg, VISA-A 75 ± 16) with clinically diagnosed unilateral Achilles tendinopathy and sonographic evident tendinosis. Intervention: IBF was assessed using Doppler ultrasound "Advanced Dynamic Flow" before (Upre) and 5, 30, 60, and 120 min (U5-U120) after a standardized submaximal constant load run. Main Outcome Measure: IBF was quantified by counting the number (n) of vessels in each tendon. Results: At Upre, IBF was higher in symptomatic compared with asymptomatic tendons [mean 6.3 (95\% CI: 2.8-9.9) and 1.7 (0.4-2.9), p < 0.01]. Overall, 63\% of symptomatic and 47\% of asymptomatic Achilles tendons responded to exercise, whereas 16 and 11\% showed persisting IBF and 21 and 42\% remained avascular throughout the investigation. At U5, IBF increased in both symptomatic and asymptomatic tendons [difference to baseline: 2.4 (0.3-4.5) and 0.9 (0.5-1.4), p = 0.05]. At U30 to U120, IBF was still increased in symptomatic but not in asymptomatic tendons [mean difference to baseline: 1.9 (0.8-2.9) and 0.1 (-0.9 to 1.2), p < 0.01]. Conclusion: Irrespective of pathology, 47-63\% of Achilles tendons responded to exercise with an immediate acute physiological IBF increase by an average of one to two vessels ("responders"). A higher amount of baseline IBF (approximately five vessels) and a prolonged exercise-induced IBF response found in symptomatic ATs indicate a pain-associated altered intratendinous "neovascularization."}, language = {en} } @misc{RischStollSchomoelleretal.2021, author = {Risch, Lucie and Stoll, Josefine and Schom{\"o}ller, Anne and Engel, Tilman and Mayer, Frank and Cassel, Michael}, title = {Intraindividual Doppler Flow Response to Exercise Differs Between Symptomatic and Asymptomatic Achilles Tendons}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1866-8364}, doi = {10.25932/publishup-54286}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-542865}, pages = {1 -- 8}, year = {2021}, abstract = {Objective: This study investigated intraindividual differences of intratendinous blood flow (IBF) in response to running exercise in participants with Achilles tendinopathy. Design: This is a cross-sectional study. Setting: The study was conducted at the University Outpatient Clinic. Participants: Sonographic detectable intratendinous blood flow was examined in symptomatic and contralateral asymptomatic Achilles tendons of 19 participants (42 ± 13 years, 178 ± 10 cm, 76 ± 12 kg, VISA-A 75 ± 16) with clinically diagnosed unilateral Achilles tendinopathy and sonographic evident tendinosis. Intervention: IBF was assessed using Doppler ultrasound "Advanced Dynamic Flow" before (Upre) and 5, 30, 60, and 120 min (U5-U120) after a standardized submaximal constant load run. Main Outcome Measure: IBF was quantified by counting the number (n) of vessels in each tendon. Results: At Upre, IBF was higher in symptomatic compared with asymptomatic tendons [mean 6.3 (95\% CI: 2.8-9.9) and 1.7 (0.4-2.9), p < 0.01]. Overall, 63\% of symptomatic and 47\% of asymptomatic Achilles tendons responded to exercise, whereas 16 and 11\% showed persisting IBF and 21 and 42\% remained avascular throughout the investigation. At U5, IBF increased in both symptomatic and asymptomatic tendons [difference to baseline: 2.4 (0.3-4.5) and 0.9 (0.5-1.4), p = 0.05]. At U30 to U120, IBF was still increased in symptomatic but not in asymptomatic tendons [mean difference to baseline: 1.9 (0.8-2.9) and 0.1 (-0.9 to 1.2), p < 0.01]. Conclusion: Irrespective of pathology, 47-63\% of Achilles tendons responded to exercise with an immediate acute physiological IBF increase by an average of one to two vessels ("responders"). A higher amount of baseline IBF (approximately five vessels) and a prolonged exercise-induced IBF response found in symptomatic ATs indicate a pain-associated altered intratendinous "neovascularization."}, 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} } @misc{QuarmbyMoennigMugeleetal.2023, author = {Quarmby, Andrew and M{\"o}nnig, Jamal and Mugele, Hendrik and Henschke, Jakob and Kim, MyoungHwee and Cassel, Michael and Engel, Tilman}, title = {Biomechanics and lower limb function are altered in athletes and runners with achilles tendinopathy compared with healthy controls: A systematic review}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {830}, issn = {1866-8364}, doi = {10.25932/publishup-58760}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-587603}, pages = {20}, year = {2023}, abstract = {Achilles tendinopathy (AT) is a debilitating injury in athletes, especially for those engaged in repetitive stretch-shortening cycle activities. Clinical risk factors are numerous, but it has been suggested that altered biomechanics might be associated with AT. No systematic review has been conducted investigating these biomechanical alterations in specifically athletic populations. Therefore, the aim of this systematic review was to compare the lower-limb biomechanics of athletes with AT to athletically matched asymptomatic controls. Databases were searched for relevant studies investigating biomechanics during gait activities and other motor tasks such as hopping, isolated strength tasks, and reflex responses. Inclusion criteria for studies were an AT diagnosis in at least one group, cross-sectional or prospective data, at least one outcome comparing biomechanical data between an AT and healthy group, and athletic populations. Studies were excluded if patients had Achilles tendon rupture/surgery, participants reported injuries other than AT, and when only within-subject data was available.. Effect sizes (Cohen's d) with 95\% confidence intervals were calculated for relevant outcomes. The initial search yielded 4,442 studies. After screening, twenty studies (775 total participants) were synthesised, reporting on a wide range of biomechanical outcomes. Females were under-represented and patients in the AT group were three years older on average. Biomechanical alterations were identified in some studies during running, hopping, jumping, strength tasks and reflex activity. Equally, several biomechanical variables studied were not associated with AT in included studies, indicating a conflicting picture. Kinematics in AT patients appeared to be altered in the lower limb, potentially indicating a pattern of "medial collapse". Muscular activity of the calf and hips was different between groups, whereby AT patients exhibited greater calf electromyographic amplitudes despite lower plantar flexor strength. Overall, dynamic maximal strength of the plantar flexors, and isometric strength of the hips might be reduced in the AT group. This systematic review reports on several biomechanical alterations in athletes with AT. With further research, these factors could potentially form treatment targets for clinicians, although clinical approaches should take other contributing health factors into account. The studies included were of low quality, and currently no solid conclusions can be drawn.}, language = {en} } @article{QuarmbyMoennigMugeleetal.2023, author = {Quarmby, Andrew and M{\"o}nnig, Jamal and Mugele, Hendrik and Henschke, Jakob and Kim, MyoungHwee and Cassel, Michael and Engel, Tilman}, title = {Biomechanics and lower limb function are altered in athletes and runners with achilles tendinopathy compared with healthy controls: A systematic review}, series = {Frontiers in Sports and Active Living}, journal = {Frontiers in Sports and Active Living}, publisher = {Frontiers}, address = {Lausanne, Schweiz}, issn = {2624-9367}, doi = {10.3389/fspor.2022.1012471}, pages = {20}, year = {2023}, abstract = {Achilles tendinopathy (AT) is a debilitating injury in athletes, especially for those engaged in repetitive stretch-shortening cycle activities. Clinical risk factors are numerous, but it has been suggested that altered biomechanics might be associated with AT. No systematic review has been conducted investigating these biomechanical alterations in specifically athletic populations. Therefore, the aim of this systematic review was to compare the lower-limb biomechanics of athletes with AT to athletically matched asymptomatic controls. Databases were searched for relevant studies investigating biomechanics during gait activities and other motor tasks such as hopping, isolated strength tasks, and reflex responses. Inclusion criteria for studies were an AT diagnosis in at least one group, cross-sectional or prospective data, at least one outcome comparing biomechanical data between an AT and healthy group, and athletic populations. Studies were excluded if patients had Achilles tendon rupture/surgery, participants reported injuries other than AT, and when only within-subject data was available.. Effect sizes (Cohen's d) with 95\% confidence intervals were calculated for relevant outcomes. The initial search yielded 4,442 studies. After screening, twenty studies (775 total participants) were synthesised, reporting on a wide range of biomechanical outcomes. Females were under-represented and patients in the AT group were three years older on average. Biomechanical alterations were identified in some studies during running, hopping, jumping, strength tasks and reflex activity. Equally, several biomechanical variables studied were not associated with AT in included studies, indicating a conflicting picture. Kinematics in AT patients appeared to be altered in the lower limb, potentially indicating a pattern of "medial collapse". Muscular activity of the calf and hips was different between groups, whereby AT patients exhibited greater calf electromyographic amplitudes despite lower plantar flexor strength. Overall, dynamic maximal strength of the plantar flexors, and isometric strength of the hips might be reduced in the AT group. This systematic review reports on several biomechanical alterations in athletes with AT. With further research, these factors could potentially form treatment targets for clinicians, although clinical approaches should take other contributing health factors into account. The studies included were of low quality, and currently no solid conclusions can be drawn.}, language = {en} } @article{QuarmbyKhajooeiEngeletal.2019, author = {Quarmby, Andrew James and Khajooei, Mina and Engel, Tilman and Kaplick, Hannes and Mayer, Frank}, title = {The feasibility of a split-belt instrumented treadmill running protocol with perturbations}, series = {Journal of biomechanics}, volume = {98}, journal = {Journal of biomechanics}, publisher = {Elsevier}, address = {Oxford}, issn = {0021-9290}, doi = {10.1016/j.jbiomech.2019.109493}, pages = {5}, year = {2019}, abstract = {Unexpected perturbations during locomotion can occur during daily life or sports performance. Adequate compensation for such perturbations is crucial in maintaining effective postural control. Studies utilising instrumented treadmills have previously validated perturbed walking protocols, however responses to perturbed running protocols remain less investigated. Therefore, the purpose of this study was to investigate the feasibility of a new instrumented treadmill-perturbed running protocol.
Fifteen participants (age = 2 8 +/- 3 years; height = 172 +/- 9 cm; weight = 69 +/- 10 kg; 60\% female) completed an 8-minute running protocol at baseline velocity of 2.5 m/s (9 km/h), whilst 15 one-sided belt perturbations were applied (pre-set perturbation characteristics: 150 ms delay (post-heel contact); 2.0 m/s amplitude; 100 ms duration). Perturbation characteristics and EMG responses were recorded. Bland-Altman analysis (BLA) was employed (bias +/- limits of agreement (LOA; bias +/- 1.96*SD)) and intra-individual variability of repeated perturbations was assessed via Coefficients of Variation (CV) (mean +/- SD).
On average, 9.4 +/- 2.2 of 15 intended perturbations were successful. Perturbation delay was 143 +/- 10 ms, amplitude was 1.7 +/- 0.2 m/s and duration was 69 +/- 10 ms. BLA showed -7 +/- 13 ms for delay, -0.3 +/- 0.1 m/s for amplitude and -30 +/- 10 ms for duration. CV showed variability of 19 +/- 4.5\% for delay, 58 +/- 12\% for amplitude and 30 +/- 7\% for duration. EMG RMS amplitudes of the legs and trunk ranged from 113 +/- 25\% to 332 +/- 305\% when compared to unperturbed gait. This study showed that the application of sudden perturbations during running can be achieved, though with increased variability across individuals. The perturbations with the above characteristics appear to have elicited a neuromuscular response during running.}, language = {en} } @misc{NairLinKhajooeietal.2020, author = {Nair, Alexandra and Lin, Chiao-I and Khajooei, Mina and Heikkila, Mika and Engel, Tilman and Mayer, Frank}, title = {Side comparison of knee muscle activities in response to perturbed walking of unilateral ankle instability}, series = {Medicine and science in sports and exercise : MSSE}, volume = {52}, journal = {Medicine and science in sports and exercise : MSSE}, number = {17}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia}, issn = {0195-9131}, doi = {10.1249/01.mss.0000671088.10003.6b}, pages = {97 -- 97}, year = {2020}, abstract = {Acute ankle sprain leads in 40\% of all cases to chronic ankle instability (CAI). CAI is related to a variety of motor adaptations at the lower extremities. Previous investigations identified increased muscle activities while landing in CAI compared to healthy control participants. However, it remains unclear whether muscular alterations at the knee muscles are limited to the involved (unstable) ankle or are also present at the uninvolved leg. The latter might potentially indicate a risk of ankle sprain or future injury on the uninvolved leg. Purpose: To assess if there is a difference of knee muscle activities between the involved and uninvolved leg in participants with CAI during perturbed walking. Method: 10 participants (6 females; 4 males; 26±4 years; 169±9 cm; 65±7 kg) with unilateral CAI walked on a split-belt treadmill (1m/s) for 5 minutes of baseline walking and 6 minutes of perturbed walking (left and right side, each 10 perturbations). Electromyography (EMG) measurements were performed at biceps femoris (BF) and rectus femoris (RF). EMG amplitude (RMS; normalized to MVIC) were analyzed for 200ms pre-heel contact (Pre200), 100ms post heel contact (Post100) and 200ms after perturbation (Pert200). Data was analyzed by paired t-test/Wilcoxon test based on presence or absence of normal distribution (Bonferroni adjusted α level p≤ 0.0125). Results: No statistical difference was found between involved and uninvolved leg for RF (Pre200: 4±2\% and 11± 22\%, respectively, p= 0.878; Post100: 10± 5 and 18±31\%, p=0.959; Pert200: 6±3\% and 13±24\%, p=0.721) as well as for BF (Pre200: 12±7\% and 11±6, p=0.576; Post100: 10±7\% and 9±7\%, p=0.732; Pert200: 7±4 and 7±7\%, p=0.386). Discussion: No side differences in muscle activity could be revealed for assessed feedforward and feedback responses (perturbed and unperturbed) in unilateral CAI. Reduced inter-individual variability of muscular activities at the involved leg might indicate a rather stereotypical response pattern. It remains to be investigated, whether muscular control at the knee is not affected by CAI, or whether both sides adapted in a similar style to the chronic condition at the ankle.}, language = {en} }