TY - CHAP A1 - Engel, Tilman A1 - Müller, Juliane A1 - Müller, Steffen A1 - Reschke, Antje A1 - Kopinski, Stephan A1 - Mayer, Frank T1 - Validity and reliability of a new customised split-belt treadmill provoking unexpected walking perturbations T2 - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine Y1 - 2013 SN - 0195-9131 SN - 1530-0315 VL - 45 IS - 5 SP - 462 EP - 462 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - CHAP A1 - Hain, Gerrit A1 - Müller, Juliane A1 - Müller, Steffen A1 - Reschke, Antje A1 - Mayer, Frank T1 - Reliability of an in-vivo 3-segmental kinematic trunk model in a one-handed lifting task T2 - Medicine and science in sports and exercise : official journal of the American College of Sports Medicine Y1 - 2013 SN - 0195-9131 SN - 1530-0315 VL - 45 IS - 5 SP - 174 EP - 174 PB - Lippincott Williams & Wilkins CY - Philadelphia ER - TY - 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 - JOUR A1 - König, Niklas A1 - Reschke, Antje A1 - Wolter, Martin A1 - Müller, Steffen A1 - Mayer, Frank A1 - Baur, Heiner T1 - Plantar pressure trigger for reliable nerve stimulus application during dynamic H-reflex measurements JF - Gait & posture N2 - In dynamic H-reflex measurements, the standardisation of the nerve stimulation to the gait cycle is crucial to avoid misinterpretation due to altered pre-synaptic inhibition. In this pilot study, a plantar pressure sole was used to trigger the stimulation of the tibialis nerve with respect to the gait cycle. Consequently, the intersession reliability of the soleus muscle H-reflex during treadmill walking was investigated. Seven young participants performed walking trials on a treadmill at 5 km/h. The stimulating electrode was placed on the tibial nerve in the popliteal fossa. An EMG was recorded from the soleus muscle. To synchronize the stimulus to the gait cycle, initial heel strike was detected with a plantar pressure sole. Maximum H-reflex amplitude and M-wave amplitude were obtained and the Hmax/Mmax ratio was calculated. Data reveals excellent reliability, ICC = 0.89. Test-retest variability was 13.0% (+/- 11.8). The Bland-Altman analysis showed a systematic error of 2.4%. The plantar pressure sole was capable of triggering the stimulation of the tibialis nerve in a reliable way and offers a simple technique for the evaluation of reflex activity during walking. KW - Monosynaptic reflexes KW - Reflex reproducibility KW - Treadmill walking Y1 - 2013 U6 - https://doi.org/10.1016/j.gaitpost.2012.09.021 SN - 0966-6362 VL - 37 IS - 4 SP - 637 EP - 639 PB - Elsevier CY - Clare ER - TY - JOUR A1 - Müller, Juliane A1 - Müller, Steffen A1 - Baur, Heiner A1 - Mayer, Frank T1 - Intra-individual gait speed variability in healthy children aged 1-15 years JF - Gait & posture N2 - Introduction: Gait speed is one of the most commonly and frequently used parameters to evaluate gait development. It is characterized by high variability when comparing different steps in children. The objective of this study was to determine intra-individual gait speed variability in children. Methods: Gait speed measurements (6-10 trials across a 3 m walkway) were performed and analyzed in 8263 children, aged 1-15 years. The coefficient of variation (CV) served as a measure for intra-individual gait speed variability measured in 6.6 +/- 1.0 trials per child. Multiple linear regression analysis was conducted to evaluate the influence of age and body height on changes in variability. Additionally, a subgroup analysis for height within the group of 6-year-old children was applied. Results: A successive reduction in gait speed variability (CV) was observed for age groups (age: 1-15 years) and body height groups (height: 0.70-1.90 m). The CV in the oldest subjects was only one third of the CV (CV 6.25 +/- 3.52%) in the youngest subjects (CV 16.58 +/- 10.01%). Up to the age of 8 years (or 1.40 m height) there was a significant reduction in CV over time, compared to a leveling off for the older (taller) children. Discussion: The straightforward approach measuring gait speed variability in repeated trials might serve as a fundamental indicator for gait development in children. Walking velocity seems to increase to age 8. Enhanced gait speed consistency of repeated trials develops up to age 15. KW - Development KW - Gait KW - Speed KW - Variability KW - Children Y1 - 2013 U6 - https://doi.org/10.1016/j.gaitpost.2013.02.011 SN - 0966-6362 SN - 1879-2219 VL - 38 IS - 4 SP - 631 EP - 636 PB - Elsevier CY - Clare ER - TY - JOUR A1 - Prieske, Olaf A1 - Mühlbauer, Thomas A1 - Müller, Steffen A1 - Krüger, Tom A1 - Kibele, Armin A1 - Behm, David George A1 - Granacher, Urs T1 - Effects of surface instability on neuromuscular performance during drop jumps and landings JF - European journal of applied physiology N2 - The purpose of this study was to investigate the effects of surface instability on measures of performance and activity of leg and trunk muscles during drop jumps and landings. Drop jumps and landings were assessed on a force plate under stable and unstable (balance pad on top of the force plate) conditions. Performance measures (contact time, jump height, peak ground reaction force) and electromyographic (EMG) activity of leg and trunk muscles were tested in 27 subjects (age 23 +/- A 3 years) during different time intervals (preactivation phase, braking phase, push-off phase). The performance of drop jumps under unstable compared to stable conditions produced a decrease in jump height (9 %, p < 0.001, f = 0.92) and an increase in peak ground reaction force (5 %, p = 0.022, f = 0.72), and time for braking phase (12 %, p < 0.001, f = 1.25). When performing drop jumps on unstable compared to stable surfaces, muscle activity was reduced in the lower extremities during the preactivation, braking and push-off phases (11-25 %, p < 0.05, 0.48 a parts per thousand currency sign f a parts per thousand currency sign 1.23). Additionally, when landing on unstable compared to stable conditions, reduced lower limb muscle activities were observed during the preactivation phase (7-60 %, p < 0.05, 0.50 a parts per thousand currency sign f a parts per thousand currency sign 3.62). Trunk muscle activity did not significantly differ between the test conditions for both jumping and landing tasks. The present findings indicate that modified feedforward mechanisms in terms of lower leg muscle activities during the preactivation phase and/or possible alterations in leg muscle activity shortly after ground contact (i.e., braking phase) are responsible for performance decrements during jumping on unstable surfaces. KW - Stretch-shortening cycle KW - Trunk muscle strength KW - Jump height KW - Electromyography Y1 - 2013 U6 - https://doi.org/10.1007/s00421-013-2724-6 SN - 1439-6319 SN - 1439-6327 VL - 113 IS - 12 SP - 2943 EP - 2951 PB - Springer CY - New York 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 -