@article{BrunnerHoolePerrier2011, author = {Brunner, Jana and Hoole, Phil and Perrier, Pascal}, title = {Adaptation strategies in perturbed /s/}, series = {Clinical linguistics \& phonetics}, volume = {25}, journal = {Clinical linguistics \& phonetics}, number = {8}, publisher = {Taylor \& Francis Group}, address = {London}, issn = {0269-9206}, doi = {10.3109/02699206.2011.553699}, pages = {705 -- 724}, year = {2011}, abstract = {The purpose of this work is to investigate the role of three articulatory parameters (tongue position, jaw position and tongue grooving) in the production of /s/. Six normal speakers' speech was perturbed by a palatal prosthesis. The fricative was recorded acoustically and through electromagnetic articulography in four conditions: (1) unperturbed, (2) perturbed with auditory feedback masked, (3) perturbed with auditory feedback available and (4) perturbed after a 2-week adaptation period. At the end of the adaptation, speakers produced more high-frequency noise while either having a higher jaw position or more grooving of the tongue or both. We discuss the potential clinical implications of the results with regard to the role of jaw height and tongue grooving in the treatment of impaired /s/.}, language = {en} } @article{BrunnerHoole2012, author = {Brunner, Jana and Hoole, Phil}, title = {Motor equivalent strategies in the production of german/integral/ under perturbation}, series = {Language and speech}, volume = {55}, journal = {Language and speech}, number = {7}, publisher = {Sage Publ.}, address = {London}, issn = {0023-8309}, doi = {10.1177/0023830911434098}, pages = {457 -- 476}, year = {2012}, abstract = {The German sibilant /integral/ is produced with a constriction in the postalveolar region and often with protruded lips. By covarying horizontal lip and tongue position speakers can keep a similar acoustic output even if the articulation varies. This study investigates whether during two weeks of adaptation to an artificial palate speakers covary these two articulatory parameters, whether tactile landmarks have an influence on the covariation and to what extent speakers can foresee the acoustic result of the covariation without auditory feedback. Six German speakers were recorded with EMA. Four of them showed a covariation of lip and tongue, which is consistent with the motor equivalence hypothesis. The acoustic output, however, does not stay entirely constant but varies with the tongue position. The role of tactile landmarks is negligible. To a certain extent, speakers are able to adapt even without auditory feedback.}, language = {en} } @article{MuellerEngelMuelleretal.2018, author = {Mueller, Steffen and Engel, Tilman and M{\"u}ller, Juliane and Stoll, Josefine and Baur, Heiner and Mayer, Frank}, title = {Sensorimotor exercises and enhanced trunk function}, series = {International journal of sports medicine}, volume = {39}, journal = {International journal of sports medicine}, number = {7}, publisher = {Thieme}, address = {Stuttgart}, issn = {0172-4622}, doi = {10.1055/a-0592-7286}, pages = {555 -- 563}, year = {2018}, abstract = {The aim of this study was to investigate the effect of a 6-week sensorimotor or resistance training on maximum trunk strength and response to sudden, high-intensity loading in athletes. Interventions showed no significant difference for maximum strength in concentric and eccentric testing (p>0.05). For perturbation compensation, higher peak torque response following SMT (Extension: +24Nm 95\%CI +/- 19Nm; Rotation: + 19Nm 95\%CI +/- 13Nm) and RT (Extension: +35Nm 95\%CI +/- 16Nm; Rotation: +5Nm 95\%CI +/- 4Nm) compared to CG (Extension: -4Nm 95\%CI +/- 16Nm; Rotation: -2Nm 95\%CI +/- 4Nm) was present (p<0.05).}, language = {en} } @article{MuellerMuellerStolletal.2022, author = {Mueller, Steffen and Mueller, Juliane and Stoll, Josefine and Mayer, Frank}, title = {Effect of six-week resistance and sensorimotor training on trunk strength and stability in elite adolescent athletes}, series = {Frontiers in physiology}, volume = {13}, journal = {Frontiers in physiology}, publisher = {Frontiers Media}, address = {Lausanne}, issn = {1664-042X}, doi = {10.3389/fphys.2022.802315}, pages = {10}, year = {2022}, abstract = {Intervention in the form of core-specific stability exercises is evident to improve trunk stability. The purpose was to assess the effect of an additional 6 weeks sensorimotor or resistance training on maximum isokinetic trunk strength and response to sudden dynamic trunk loading (STL) in highly trained adolescent athletes. The study was conducted as a single-blind, 3-armed randomized controlled trial. Twenty-four adolescent athletes (14f/10 m, 16 +/- 1 yrs.;178 +/- 10 cm; 67 +/- 11 kg; training sessions/week 15 +/- 5; training h/week 22 +/- 8) were randomized into resistance training (RT; n = 7), sensorimotor training (SMT; n = 10), and control group (CG; n = 7). Athletes were instructed to perform standardized, center-based training for 6 weeks, two times per week, with a duration of 1 h each session. SMT consisted of four different core-specific sensorimotor exercises using instable surfaces. RT consisted of four trunk strength exercises using strength training machines, as well as an isokinetic dynamometer. All participants in the CG received an unspecific heart frequency controlled, ergometer-based endurance training (50 min at max. heart frequency of 130HF). For each athlete, each training session was documented in an individual training diary (e.g., level of SMT exercise; 1RM for strength exercise, pain). At baseline (M1) and after 6 weeks of intervention (M2), participants' maximum strength in trunk rotation (ROM:63 degrees) and flexion/extension (ROM:55 degrees) was tested on an isokinetic dynamometer (concentric/eccentric 30 degrees/s). STL was assessed in eccentric (30 degrees/s) mode with additional dynamometer-induced perturbation as a marker of core stability. Peak torque [Nm] was calculated as the main outcome. The primary outcome measurements (trunk rotation/extension peak torque: con, ecc, STL) were statistically analyzed by means of the two-factor repeated measures analysis of variance (alpha = 0.05). Out of 12 possible sessions, athletes participated between 8 and 9 sessions (SMT: 9 +/- 3; RT: 8 +/- 3; CG: 8 +/- 4). Regarding main outcomes of trunk performance, experimental groups showed no significant pre-post difference for maximum trunk strength testing as well as for perturbation compensation (p > 0.05). It is concluded, that future interventions should exceed 6 weeks duration with at least 2 sessions per week to induce enhanced trunk strength or compensatory response to sudden, high-intensity trunk loading in already highly trained adolescent athletes, regardless of training regime.}, language = {en} } @article{QuarmbyKhajooeiKurtzetal.2023, author = {Quarmby, Andrew James and Khajooei, Mina and Kurtz, Philip and Henschke, Jakob and Kim, MyoungHwee and Mayer, Frank and Engel, Tilman}, title = {Unexpected running perturbations}, series = {Frontiers in sports and active living}, volume = {5}, journal = {Frontiers in sports and active living}, publisher = {Frontiers Media}, address = {Lausanne}, issn = {2624-9367}, doi = {10.3389/fspor.2023.1129058}, pages = {14}, year = {2023}, abstract = {Introduction Balance is vital for human health and experiments have been conducted to measure the mechanisms of postural control, for example studying reflex responses to simulated perturbations. Such studies are frequent in walking but less common in running, and an understanding of reflex responses to trip-like disturbances could enhance our understanding of human gait and improve approaches to training and rehabilitation. Therefore, the primary aim of this study was to investigate the technical validity and reliability of a treadmill running protocol with perturbations. A further exploratory aim was to evaluate the associated neuromuscular reflex responses to the perturbations, in the lower limbs. Methods Twelve healthy participants completed a running protocol (9 km/h) test-retest (2 weeks apart), whereby 30 unilateral perturbations were executed via the treadmill belts (presets:2.0 m/s amplitude;150 ms delay (post-heel contact);100ms duration). Validity of the perturbations was assessed via mean +/- SD comparison, percentage error calculation between the preset and recorded perturbation characteristics (PE\%), and coefficient of variation (CV\%). Test-retest reliability (TRV\%) and Bland-Altman analysis (BLA; bias +/- 1.96 * SD) was calculated for reliability. To measure reflex activity, electromyography (EMG) was applied in both legs. EMG amplitudes (root mean square normalized to unperturbed strides) and latencies [ms] were analysed descriptively. Results Left-side perturbation amplitude was 1.9 +/- 0.1 m/s, delay 105 +/- 2 ms, and duration 78 +/- 1 ms. Right-side perturbation amplitude was 1.9 +/- 0.1 m/s, delay 118 +/- 2 ms, duration 78 +/- 1 ms. PE\% ranged from 5-30\% for the recorded perturbations. CV\% of the perturbations ranged from 19.5-76.8\%. TRV\% for the perturbations was 6.4-16.6\%. BLA for the left was amplitude: 0.0 +/- 0.3m/s, delay: 0 +/- 17 ms, duration: 2 +/- 13 ms, and for the right was amplitude: 0.1 +/- 0.7, delay: 4 +/- 40 ms, duration: 1 +/- 35 ms. EMG amplitudes ranged from 175 +/- 141\%-454 +/- 359\% in both limbs. Latencies were 109 +/- 12-116 +/- 23 ms in the tibialis anterior, and 128 +/- 49-157 +/- 20 ms in the biceps femoris. Discussion Generally, this study indicated sufficient validity and reliability of the current setup considering the technical challenges and limitations, although the reliability of the right-sided perturbations could be questioned. The protocol provoked reflex responses in the lower extremities, especially in the leading leg. Acute neuromusculoskeletal adjustments to the perturbations could be studied and compared in clinical and healthy running populations, and the protocol could be utilised to monitor chronic adaptations to interventions over time.}, language = {en} }