@inproceedings{EngelMuellerMuelleretal.2013,
author = {Engel, Tilman and M{\"u}ller, Juliane and M{\"u}ller, Steffen and Reschke, Antje and Kopinski, Stephan and Mayer, Frank},
title = {Validity and reliability of a new customised split-belt treadmill provoking unexpected walking perturbations},
series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
volume = {45},
booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
number = {5},
publisher = {Lippincott Williams \& Wilkins},
address = {Philadelphia},
issn = {0195-9131},
pages = {462 -- 462},
year = {2013},
language = {en}
}
@article{EngelMuellerKopinskietal.2017,
author = {Engel, Tilman and Mueller, Juliane and Kopinski, Stephan and Reschke, Antje and Mueller, Steffen and Mayer, Frank},
title = {Unexpected walking perturbations: Reliability and validity of a new treadmill protocol to provoke muscular reflex activities at lower extremities and the trunk},
series = {Journal of biomechanics},
volume = {55},
journal = {Journal of biomechanics},
publisher = {Elsevier},
address = {Oxford},
issn = {0021-9290},
doi = {10.1016/j.jbiomech.2017.02.026},
pages = {152 -- 155},
year = {2017},
abstract = {Instrumented treadmills offer the potential to generate standardized walking perturbations, which are particularly rapid and powerful. However, technical requirements to release adequate perturbations regarding timing, duration and amplitude are demanding. This study investigated the test-retest reliability and validity of a new treadmill perturbation protocol releasing rapid and unexpected belt perturbations to provoke muscular reflex responses at lower extremities and the trunk. Fourteen healthy participants underwent two identical treadmill walking protocols, consisting of 10 superimposed one-sided belt perturbations (100 ms duration; 2 m/s amplitude), triggered by a plantar pressure insole 200 ms after heel contact. Delay, duration and amplitude of applied perturbations were recorded by 3D-motion capture. Muscular reflex responses (within 200 ms) were measured at lower extremities and the trunk (10-lead EMG). Data was analyzed descriptively (mean +/- SD). Reliability was analyzed using test-retest variability (TRV\%) and limits of agreement (LoA, bias +/- 1.96*SD). Perturbation delay was 202 14 ms, duration was 102 +/- 4 ms and amplitude was 2.1 +/- 0.01 m/s. TRV for perturbation delay, duration and amplitude ranged from 5.0\% to 5.7\%. LoA reached 3 +/- 36 ms for delay, 2 +/- 13 ms for duration and 0.0 +/- 0.3 m/s for amplitude. EMG amplitudes following perturbations ranged between 106 +/- 97\% and 909 +/- 979\% of unperturbed gait and EMG latencies between 82 +/- 14 ms and 106 +/- 16 ms. Minor differences between preset and observed perturbation characteristics and results of test-retest analysis prove a high validity with excellent reliability of the setup. Therefore, the protocol tested can be recommended to provoke muscular reflex responses at lower extremities and the trunk in perturbed walking. (C) 2017 Elsevier Ltd. All rights reserved.},
language = {en}
}
@article{KopinskiEngelCasseletal.2015,
author = {Kopinski, Stephan and Engel, Tilman and Cassel, Michael and Fr{\"o}hlich, Katja and Mayer, Frank and Carlsohn, Anja},
title = {Ultrasound Applied to Subcutaneous Fat Tissue Measurements in International Elite Canoeists},
series = {International journal of sports medicine},
volume = {36},
journal = {International journal of sports medicine},
number = {14},
publisher = {Thieme},
address = {Stuttgart},
issn = {0172-4622},
doi = {10.1055/s-0035-1555857},
pages = {1134 -- 1141},
year = {2015},
abstract = {Subcutaneous adipose tissue (SAT) measurements with ultrasound have recently been introduced to assess body fat in elite athletes. However, appropriate protocols and data on various groups of athletes are missing. We investigated intra-rater reliability of SAT measurements using ultrasound in elite canoe athletes. 25 international level canoeists (18 male, 7 female; 23 +/- 4 years; 81 +/- 11 kg; 1.83 +/- 0.09 m; 20 +/- 3 training h/wk) were measured on 2 consecutive days. SAT was assessed with B-mode ultrasound at 8 sites (ISAK): triceps, subscapular, biceps, iliac crest, supraspinal, abdominal, front thigh, medial calf, and quantified using image analysis software. Data was analyzed descriptively (mean +/- SD, [range]). Coefficient of variation (CV \%), intraclass correlation coefficient (ICC, 2.1) and absolute (LoA) and ratio limits of agreement (RLoA) were calculated for day-to-day reliability. Mean sum of SAT thickness was 30.0 +/- 19.4 mm [8.0, 80.1 mm], with 3.9 +/- 1.8 mm [1.2 mm subscapular, 8.0 mm abdominal] for individual sites. CV for the sum of sites was 4.7 \%, ICC 0.99, LoA 1.7 +/- 3.6 mm, RLoA 0.940 (*/divided by 1.155). Measuring SAT with ultrasound has proved to have excellent day-to-day reliability in elite canoe athletes. Recommendations for standardization of the method will further increase accuracy and reproducibility.},
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}
}
@inproceedings{KopinskiEngelMuelleretal.2013,
author = {Kopinski, Stephan and Engel, Tilman and M{\"u}ller, Steffen and Mayer, Frank},
title = {Torque-EMG relationship of lower back muscles - 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 = {7 -- 8},
year = {2013},
language = {en}
}
@inproceedings{ReschkeMuellerMuelleretal.2013,
author = {Reschke, Antje and M{\"u}ller, Juliane and M{\"u}ller, Steffen and Engel, Tilman and Mayer, Frank},
title = {Three-dimensional spine kinematics during perturbed treadmill walking - a pilot study},
series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
volume = {45},
booktitle = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
number = {5},
publisher = {Lippincott Williams \& Wilkins},
address = {Philadelphia},
issn = {0195-9131},
pages = {172 -- 172},
year = {2013},
language = {en}
}
@article{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}
}
@article{LinKhajooeiEngeletal.2021,
author = {Lin, Chiao-I and Khajooei, Mina and Engel, Tilman and Nair, Alexandra and Heikkila, Mika and Kaplick, Hannes and Mayer, Frank},
title = {The effect of chronic ankle instability on muscle activations in lower extremities},
series = {PLOS ONE / Public Library of Science},
volume = {16},
journal = {PLOS ONE / Public Library of Science},
number = {2},
publisher = {PLOS},
address = {San Francisco},
issn = {1932-6203},
doi = {10.1371/journal.pone.0247581},
pages = {15},
year = {2021},
abstract = {Background/Purpose Muscular reflex responses of the lower extremities to sudden gait disturbances are related to postural stability and injury risk. Chronic ankle instability (CAI) has shown to affect activities related to the distal leg muscles while walking. Its effects on proximal muscle activities of the leg, both for the injured- (IN) and uninjured-side (NON), remain unclear. Therefore, the aim was to compare the difference of the motor control strategy in ipsilateral and contralateral proximal joints while unperturbed walking and perturbed walking between individuals with CAI and matched controls. Materials and methods In a cross-sectional study, 13 participants with unilateral CAI and 13 controls (CON) walked on a split-belt treadmill with and without random left- and right-sided perturbations. EMG amplitudes of muscles at lower extremities were analyzed 200 ms after perturbations, 200 ms before, and 100 ms after (Post100) heel contact while walking. Onset latencies were analyzed at heel contacts and after perturbations. Statistical significance was set at alpha≤0.05 and 95\% confidence intervals were applied to determine group differences. Cohen's d effect sizes were calculated to evaluate the extent of differences. Results Participants with CAI showed increased EMG amplitudes for NON-rectus abdominus at Post100 and shorter latencies for IN-gluteus maximus after heel contact compared to CON (p<0.05). Overall, leg muscles (rectus femoris, biceps femoris, and gluteus medius) activated earlier and less bilaterally (d = 0.30-0.88) and trunk muscles (bilateral rectus abdominus and NON-erector spinae) activated earlier and more for the CAI group than CON group (d = 0.33-1.09). Conclusion Unilateral CAI alters the pattern of the motor control strategy around proximal joints bilaterally. Neuromuscular training for the muscles, which alters motor control strategy because of CAI, could be taken into consideration when planning rehabilitation for CAI.},
language = {en}
}
@misc{LinKhajooeiEngeletal.2012,
author = {Lin, Chiao-I and Khajooei, Mina and Engel, Tilman and Nair, Alexandra and Heikkila, Mika and Kaplick, Hannes and Mayer, Frank},
title = {The effect of chronic ankle instability on muscle activations in lower extremities},
series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
issn = {1866-8364},
doi = {10.25932/publishup-51563},
url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-515632},
pages = {17},
year = {2012},
abstract = {Background/Purpose Muscular reflex responses of the lower extremities to sudden gait disturbances are related to postural stability and injury risk. Chronic ankle instability (CAI) has shown to affect activities related to the distal leg muscles while walking. Its effects on proximal muscle activities of the leg, both for the injured- (IN) and uninjured-side (NON), remain unclear. Therefore, the aim was to compare the difference of the motor control strategy in ipsilateral and contralateral proximal joints while unperturbed walking and perturbed walking between individuals with CAI and matched controls. Materials and methods In a cross-sectional study, 13 participants with unilateral CAI and 13 controls (CON) walked on a split-belt treadmill with and without random left- and right-sided perturbations. EMG amplitudes of muscles at lower extremities were analyzed 200 ms after perturbations, 200 ms before, and 100 ms after (Post100) heel contact while walking. Onset latencies were analyzed at heel contacts and after perturbations. Statistical significance was set at alpha≤0.05 and 95\% confidence intervals were applied to determine group differences. Cohen's d effect sizes were calculated to evaluate the extent of differences. Results Participants with CAI showed increased EMG amplitudes for NON-rectus abdominus at Post100 and shorter latencies for IN-gluteus maximus after heel contact compared to CON (p<0.05). Overall, leg muscles (rectus femoris, biceps femoris, and gluteus medius) activated earlier and less bilaterally (d = 0.30-0.88) and trunk muscles (bilateral rectus abdominus and NON-erector spinae) activated earlier and more for the CAI group than CON group (d = 0.33-1.09). Conclusion Unilateral CAI alters the pattern of the motor control strategy around proximal joints bilaterally. Neuromuscular training for the muscles, which alters motor control strategy because of CAI, could be taken into consideration when planning rehabilitation for CAI.},
language = {en}
}
@article{MuellerMuellerEngeletal.2016,
author = {M{\"u}ller, Juliane and M{\"u}ller, Steffen and Engel, Tilman and Reschke, Antje and Baur, Heiner and Mayer, Frank},
title = {Stumbling reactions during perturbed walking: Neuromuscular reflex activity and 3-D kinematics of the trunk - A pilot study},
series = {Journal of biomechanics},
volume = {49},
journal = {Journal of biomechanics},
publisher = {Elsevier},
address = {Oxford},
issn = {0021-9290},
doi = {10.1016/j.jbiomech.2015.09.041},
pages = {933 -- 938},
year = {2016},
abstract = {Stumbling led to an increase in ROM, compared to unperturbed gait, in all segments and planes. These increases ranged between 107 +/- 26\% (UTA/rotation) and 262 +/- 132\% (UTS/lateral flexion), significant only in lateral flexion. EMG activity of the trunk was increased during stumbling (abdominal: 665 +/- 283\%; back: 501 +/- 215\%), without significant differences between muscles. Provoked stumbling leads to a measurable effect on the trunk, quantifiable by an increase in ROM and EMG activity, compared to normal walking. Greater abdominal muscle activity and ROM of lateral flexion may indicate a specific compensation pattern occurring during stumbling. (C) 2015 Elsevier Ltd. All rights reserved.},
language = {en}
}