TY - CHAP
A1 - Engel, Tilman
A1 - Müller, Juliane
A1 - Müller, Steffen
A1 - Reschke, Antje
A1 - Kopinski, Stephan
A1 - Mayer, Frank
T1 - Validity and reliability of a new customised split-belt treadmill provoking unexpected walking perturbations
T2 - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine
Y1 - 2013
SN - 0195-9131
SN - 1530-0315
VL - 45
IS - 5
SP - 462
EP - 462
PB - Lippincott Williams & Wilkins
CY - Philadelphia
ER -
TY - JOUR
A1 - Engel, Tilman
A1 - Mueller, Juliane
A1 - Kopinski, Stephan
A1 - Reschke, Antje
A1 - Mueller, Steffen
A1 - Mayer, Frank
T1 - Unexpected walking perturbations: Reliability and validity of a new treadmill protocol to provoke muscular reflex activities at lower extremities and the trunk
JF - Journal of biomechanics
N2 - 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.
KW - Perturbation
KW - Stumbling
KW - Gait
KW - Treadmill
KW - Reliability
KW - MiSpEx
Y1 - 2017
U6 - https://doi.org/10.1016/j.jbiomech.2017.02.026
SN - 0021-9290
SN - 1873-2380
VL - 55
SP - 152
EP - 155
PB - Elsevier
CY - Oxford
ER -
TY - JOUR
A1 - Kopinski, Stephan
A1 - Engel, Tilman
A1 - Cassel, Michael
A1 - Fröhlich, Katja
A1 - Mayer, Frank
A1 - Carlsohn, Anja
T1 - Ultrasound Applied to Subcutaneous Fat Tissue Measurements in International Elite Canoeists
JF - International journal of sports medicine
N2 - 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.
KW - subcutaneous adipose tissue
KW - skinfold thickness
KW - elite athletes
KW - body composition
KW - ultrasonography
Y1 - 2015
U6 - https://doi.org/10.1055/s-0035-1555857
SN - 0172-4622
SN - 1439-3964
VL - 36
IS - 14
SP - 1134
EP - 1141
PB - Thieme
CY - Stuttgart
ER -
TY - JOUR
A1 - Rowley, K. Michael
A1 - Engel, Tilman
A1 - Kulig, Kornelia
T1 - Trunk and hip muscle activity during the Balance-Dexterity task in persons with and without recurrent low back pain
JF - Journal of electromyography and kinesiology
N2 - 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.
KW - balance
KW - low back pain
KW - trunk and hip coordination
KW - lumbopelvic
Y1 - 2020
U6 - https://doi.org/10.1016/j.jelekin.2019.102378
SN - 1050-6411
SN - 1873-5711
VL - 50
PB - Elsevier Science
CY - Amsterdam
ER -
TY - CHAP
A1 - Kopinski, Stephan
A1 - Engel, Tilman
A1 - Müller, Steffen
A1 - Mayer, Frank
T1 - Torque-EMG relationship of lower back muscles - a pilot study
T2 - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine
Y1 - 2013
SN - 0195-9131
SN - 1530-0315
VL - 45
IS - 5
SP - 7
EP - 8
PB - Lippincott Williams & Wilkins
CY - Philadelphia
ER -
TY - CHAP
A1 - Reschke, Antje
A1 - Müller, Juliane
A1 - Müller, Steffen
A1 - Engel, Tilman
A1 - Mayer, Frank
T1 - Three-dimensional spine kinematics during perturbed treadmill walking - a pilot study
T2 - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine
Y1 - 2013
SN - 0195-9131
SN - 1530-0315
VL - 45
IS - 5
SP - 172
EP - 172
PB - Lippincott Williams & Wilkins
CY - Philadelphia
ER -
TY - JOUR
A1 - Quarmby, Andrew James
A1 - Khajooei, Mina
A1 - Engel, Tilman
A1 - Kaplick, Hannes
A1 - Mayer, Frank
T1 - The feasibility of a split-belt instrumented treadmill running protocol with perturbations
JF - Journal of biomechanics
N2 - 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.
KW - Lower-extremity perturbations
KW - Split-belt treadmill
KW - Running
KW - Stumbling
KW - EMC
Y1 - 2020
U6 - https://doi.org/10.1016/j.jbiomech.2019.109493
SN - 0021-9290
SN - 1873-2380
VL - 98
PB - Elsevier
CY - Oxford
ER -
TY - JOUR
A1 - Lin, Chiao-I
A1 - Khajooei, Mina
A1 - Engel, Tilman
A1 - Nair, Alexandra
A1 - Heikkila, Mika
A1 - Kaplick, Hannes
A1 - Mayer, Frank
T1 - The effect of chronic ankle instability on muscle activations in lower extremities
JF - PLOS ONE / Public Library of Science
N2 - 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.
KW - Ankles
KW - Walking
KW - Electromyography
KW - Hip
KW - Skeletal joints
KW - Knees
KW - Legs
KW - Musculoskeletal injury
Y1 - 2020
U6 - https://doi.org/10.1371/journal.pone.0247581
SN - 1932-6203
VL - 16
IS - 2
PB - PLOS
CY - San Francisco
ER -
TY - GEN
A1 - Lin, Chiao-I
A1 - Khajooei, Mina
A1 - Engel, Tilman
A1 - Nair, Alexandra
A1 - Heikkila, Mika
A1 - Kaplick, Hannes
A1 - Mayer, Frank
T1 - The effect of chronic ankle instability on muscle activations in lower extremities
T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe
N2 - 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.
T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 712
KW - Electromyography
KW - Hip
KW - Skeletal joints
KW - Knees
KW - Legs
KW - Musculoskeletal injury
KW - Walking
KW - Ankles
Y1 - 2021
U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-515632
SN - 1866-8364
ER -
TY - JOUR
A1 - Müller, Juliane
A1 - Müller, Steffen
A1 - Engel, Tilman
A1 - Reschke, Antje
A1 - Baur, Heiner
A1 - Mayer, Frank
T1 - Stumbling reactions during perturbed walking: Neuromuscular reflex activity and 3-D kinematics of the trunk - A pilot study
JF - Journal of biomechanics
N2 - Stumbling led to an increase in ROM, compared to unperturbed gait, in all segments and planes. These increases ranged between 107 +/- 26% (UTA/rotation) and 262 +/- 132% (UTS/lateral flexion), significant only in lateral flexion. EMG activity of the trunk was increased during stumbling (abdominal: 665 +/- 283%; back: 501 +/- 215%), without significant differences between muscles. Provoked stumbling leads to a measurable effect on the trunk, quantifiable by an increase in ROM and EMG activity, compared to normal walking. Greater abdominal muscle activity and ROM of lateral flexion may indicate a specific compensation pattern occurring during stumbling. (C) 2015 Elsevier Ltd. All rights reserved.
KW - Trunk kinematics
KW - Treadmill walking
KW - Gait perturbation
KW - EMG
Y1 - 2016
U6 - https://doi.org/10.1016/j.jbiomech.2015.09.041
SN - 0021-9290
SN - 1873-2380
VL - 49
SP - 933
EP - 938
PB - Elsevier
CY - Oxford
ER -