@article{EichlerRabeSalzwedeletal.2017,
  author    = {Eichler, Sarah and Rabe, Sophie and Salzwedel, Annett and Mueller, Steffen and Stoll, Josefine and Tilgner, Nina and John, Michael and Wegscheider, Karl and Mayer, Frank and V{\"o}ller, Heinz},
  title     = {Effectiveness of an interactive telerehabilitation system with home-based exercise training in patients after total hip or knee replacement: study protocol for a multicenter, superiority, no-blinded randomized controlled trial},
  series = {Trials},
  volume    = {18},
  journal   = {Trials},
  publisher = {BioMed Central},
  address   = {London},
  issn      = {1745-6215},
  doi       = {10.1186/s13063-017-2173-3},
  pages     = {7},
  year      = {2017},
  abstract  = {Background: Total hip or knee replacement is one of the most frequently performed surgical procedures. Physical rehabilitation following total hip or knee replacement is an essential part of the therapy to improve functional outcomes and quality of life. After discharge from inpatient rehabilitation, a subsequent postoperative exercise therapy is needed to maintain functional mobility. Telerehabilitation may be a potential innovative treatment approach. We aim to investigate the superiority of an interactive telerehabilitation intervention for patients after total hip or knee replacement, in comparison to usual care, regarding physical performance, functional mobility, quality of life and pain. Methods/design: This is an open, randomized controlled, multicenter superiority study with two prospective arms. One hundred and ten eligible and consenting participants with total knee or hip replacement will be recruited at admission to subsequent inpatient rehabilitation. After comprehensive, 3-week, inpatient rehabilitation, the intervention group performs a 3-month, interactive, home-based exercise training with a telerehabilitation system. For this purpose, the physiotherapist creates an individual training plan out of 38 different strength and balance exercises which were implemented in the system. Data about the quality and frequency of training are transmitted to the physiotherapist for further adjustment. Communication between patient and physiotherapist is possible with the system. The control group receives voluntary, usual aftercare programs. Baseline assessments are investigated after discharge from rehabilitation; final assessments 3 months later. The primary outcome is the difference in improvement between intervention and control group in 6-minute walk distance after 3 months. Secondary outcomes include differences in the Timed Up and Go Test, the Five-Times-Sit-to-Stand Test, the Stair Ascend Test, the Short-Form 36, the Western Ontario and McMaster Universities Osteoarthritis Index, the International Physical Activity Questionnaire, and postural control as well as gait and kinematic parameters of the lower limbs. Baseline-adjusted analysis of covariance models will be used to test for group differences in the primary and secondary endpoints. Discussion: We expect the intervention group to benefit from the interactive, home-based exercise training in many respects represented by the study endpoints. If successful, this approach could be used to enhance the access to aftercare programs, especially in structurally weak areas.},
  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{MuellerEngelKopinskietal.2017,
  author    = {M{\"u}ller, Juliane and Engel, Tilman and Kopinski, Stephan and Mayer, Frank and M{\"u}ller, Steffen},
  title     = {Neuromuscular trunk activation patterns in back pain patients during one-handed lifting},
  series = {World journal of orthopedics},
  volume    = {8},
  journal   = {World journal of orthopedics},
  number    = {2},
  publisher = {Baishideng Publishing Group},
  address   = {Pleasanton},
  issn      = {2218-5836},
  doi       = {10.5312/wjo.v8.i2.142},
  pages     = {142 -- 148},
  year      = {2017},
  abstract  = {AIM To analyze neuromuscular activity patterns of the trunk in healthy controls (H) and back pain patients (BPP) during one-handed lifting of light to heavy loads. METHODS RESULTS Seven subjects (3m/4f; 32 +/- 7 years; 171 +/- 7 cm; 65 +/- 11 kg) were assigned to BPP (pain grade >= 2) and 36 (13m/23f; 28 +/- 8 years; 174 +/- 10 cm; 71 +/- 12 kg) to H (pain grade <= 1). H and BPP did not differ significantly in anthropometrics (P > 0.05). All subjects were able to lift the light and middle loads, but 57\% of BPP and 22\% of H were not able to lift the heavy load (all women) chi(2) analysis revealed statistically significant differences in task failure between H vs BPP (P = 0.03). EMG-RMS ranged from 33\% +/- 10\%/30\% +/- 9\% (DL, 1 kg) to 356\% +/- 148\%/283\% +/- 80\% (VR, 20 kg) in H/BPP with no statistical difference between groups regardless of load (P > 0.05). However, the EMG-RMS of the VR was greatest in all lifting tasks for both groups and increased with heavier loads. CONCLUSION Heavier loading leads to an increase (2-to 3-fold) in trunk muscle activity with comparable patterns. Heavy loading (20 kg) leads to task failure, especially in women with back pain.},
  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{MuellerHadzicMugeleetal.2017,
  author    = {M{\"u}ller, Juliane and Hadzic, Miralem and Mugele, Hendrik and Stoll, Josefine and M{\"u}ller, Steffen and Mayer, Frank},
  title     = {Effect of high-intensity perturbations during core-specific sensorimotor exercises on trunk muscle activation},
  series = {Journal of biomechanics},
  volume    = {70},
  journal   = {Journal of biomechanics},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0021-9290},
  doi       = {10.1016/j.jbiomech.2017.12.013},
  pages     = {212 -- 218},
  year      = {2017},
  abstract  = {Core-specific sensorimotor exercises are proven to enhance neuromuscular activity of the trunk. However, the influence of high-intensity perturbations on training efficiency is unclear within this context. Sixteen participants (29 +/- 2 yrs; 175 +/- 8 cm; 69 +/- 13 kg) were prepared with a 12-lead bilateral trunk EMG. Warm-up on a dynamometer was followed by maximum voluntary isometric trunk (flex/ext) contraction (MVC). Next, participants performed four conditions for a one-legged stance with hip abduction on a stable surface (HA) repeated randomly on an unstable surface (HAP), on a stable surface with perturbation (HA + P), and on an unstable surface with perturbation (HAP + P). Afterwards, bird dog (BD) was performed under the same conditions (BD, BDP, BD + P, BDP + P). A foam pad under the foot (HA) or the knee (BD) was used as an unstable surface. Exercises were conducted on a moveable platform. Perturbations (ACC 50 m/sec(2);100 ms duration;10rep.) were randomly applied in the anterior-posterior direction. The root mean square (RMS) normalized to MVC (\%) was calculated (whole movement cycle). Muscles were grouped into ventral right and left (VR;VL), and dorsal right and left (DR;DL). Ventral Dorsal and right-left ratios were calculated (two way repeated-measures ANOVA;alpha = 0,05). Amplitudes of all muscle groups in bird dog were higher compared to hip abduction (p <= 0.0001; Range: BD: 14 +/- 3\% (BD;VR) to 53 +/- 4\%; HA: 7 +/- 2\% (HA;DR) to 16 +/- 4\% (HA;DR)). EMG-RMS showed significant differences (p < 0.001) between conditions and muscle groups per exercise. Interaction effects were only significant for HA (p = 0.02). No significant differences were present in EMG ratios (p > 0.05). Additional high-intensity perturbations during core-specific sensorimotor exercises lead to increased neuromuscular activity and therefore higher exercise intensities. However, the beneficial effects on trunk function remain unclear. Nevertheless, BD is more suitable to address trunk muscles.},
  language  = {en}
}
@article{WahmkowCasselMayeretal.2017,
  author    = {Wahmkow, Gunnar and Cassel, Michael and Mayer, Frank and Baur, Heiner},
  title     = {Effects of different medial arch support heights on rearfoot kinematics},
  series = {PLoS one},
  volume    = {12},
  journal   = {PLoS one},
  number    = {3},
  publisher = {PLoS},
  address   = {Lawrence, Kan.},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0172334},
  year      = {2017},
  abstract  = {Background Foot orthoses are usually assumed to be effective by optimizing mechanically dynamic rearfoot configuration. However, the effect from a foot orthosis on kinematics that has been demonstrated scientifically has only been marginal. The aim of this study was to examine the effect of different heights in medial arch-supported foot orthoses on rear foot motion during gait. Methods Nineteen asymptomatic runners (36±11years, 180±5cm, 79±10kg; 41±22km/week) participated in the study. Trials were recorded at 3.1 mph (5 km/h) on a treadmill. Athletes walked barefoot and with 4 different not customized medial arch-supported foot orthoses of various arch heights (N:0 mm, M:30 mm, H:35 mm, E:40mm). Six infrared cameras and the `Oxford Foot Model´ were used to capture motion. The average stride in each condition was calculated from 50 gait cycles per condition. Eversion excursion and internal tibia rotation were analyzed. Descriptive statistics included calculating the mean ± SD and 95\% CIs. Group differences by condition were analyzed by one factor (foot orthoses) repeated measures ANOVA (α = 0.05). Results Eversion excursion revealed the lowest values for N and highest for H (B:4.6°±2.2°; 95\% CI [3.1;6.2]/N:4.0°±1.7°; [2.9;5.2]/M:5.2°±2.6°; [3.6;6.8]/H:6.2°±3.3°; [4.0;8.5]/E:5.1°±3.5°; [2.8;7.5]) (p>0.05). Range of internal tibia rotation was lowest with orthosis H and highest with E (B:13.3°±3.2°; 95\% CI [11.0;15.6]/N:14.5°±7.2°; [9.2;19.6]/M:13.8°±5.0°; [10.8;16.8]/H:12.3°±4.3°; [9.0;15.6]/E:14.9°±5.0°; [11.5;18.3]) (p>0.05). Differences between conditions were small and the intrasubject variation high. Conclusion Our results indicate that different arch support heights have no systematic effect on eversion excursion or the range of internal tibia rotation and therefore might not exert a crucial influence on rear foot alignment during gait.},
  language  = {en}
}
@article{MuellerStollCasseletal.2017,
  author    = {M{\"u}ller, Steffen and Stoll, Josefine and Cassel, Michael and Mayer, Frank},
  title     = {Trunk Muscle Activity during Drop Jump Performance in Adolescent Athletes with Back Pain},
  series = {Frontiers in physiology},
  volume    = {8},
  journal   = {Frontiers in physiology},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne},
  issn      = {1664-042X},
  doi       = {10.3389/fphys.2017.00274},
  year      = {2017},
  abstract  = {In the context of back pain, great emphasis has been placed on the importance of trunk stability, especially in situations requiring compensation of repetitive, intense loading induced during high-performance activities, e.g., jumping or landing. This study aims to evaluate trunk muscle activity during drop jump in adolescent athletes with back pain (BP) compared to athletes without back pain (NBP). Eleven adolescent athletes suffering back pain (BP: m/f: n = 4/7; 15.9 ± 1.3 y; 176 ± 11 cm; 68 ± 11 kg; 12.4 ± 10.5 h/we training) and 11 matched athletes without back pain (NBP: m/f: n = 4/7; 15.5 ± 1.3 y; 174 ± 7 cm; 67 ± 8 kg; 14.9 ± 9.5 h/we training) were evaluated. Subjects conducted 3 drop jumps onto a force plate (ground reaction force). Bilateral 12-lead SEMG (surface Electromyography) was applied to assess trunk muscle activity. Ground contact time [ms], maximum vertical jump force [N], jump time [ms] and the jump performance index [m/s] were calculated for drop jumps. SEMG amplitudes (RMS: root mean square [\%]) for all 12 single muscles were normalized to MIVC (maximum isometric voluntary contraction) and analyzed in 4 time windows (100 ms pre- and 200 ms post-initial ground contact, 100 ms pre- and 200 ms post-landing) as outcome variables. In addition, muscles were grouped and analyzed in ventral and dorsal muscles, as well as straight and transverse trunk muscles. Drop jump ground reaction force variables did not differ between NBP and BP (p > 0.05). Mm obliquus externus and internus abdominis presented higher SEMG amplitudes (1.3-1.9-fold) for BP (p < 0.05). Mm rectus abdominis, erector spinae thoracic/lumbar and latissimus dorsi did not differ (p > 0.05). The muscle group analysis over the whole jumping cycle showed statistically significantly higher SEMG amplitudes for BP in the ventral (p = 0.031) and transverse muscles (p = 0.020) compared to NBP. Higher activity of transverse, but not straight, trunk muscles might indicate a specific compensation strategy to support trunk stability in athletes with back pain during drop jumps. Therefore, exercises favoring the transverse trunk muscles could be recommended for back pain treatment.},
  language  = {en}
}
@article{MartinezValdesNegroLaineetal.2017,
  author    = {Martinez-Valdes, Eduardo Andr{\´e}s and Negro, F. and Laine, C. M. and Falla, D. and Mayer, Frank and Farina, Dario},
  title     = {Tracking motor units longitudinally across experimental sessions with high-density surface electromyography},
  series = {The Journal of Physiology},
  volume    = {595},
  journal   = {The Journal of Physiology},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0022-3751},
  doi       = {10.1113/JP273662},
  pages     = {1479 -- 1496},
  year      = {2017},
  abstract  = {A new method is proposed for tracking individual motor units (MUs) across multiple experimental sessions on different days. The technique is based on a novel decomposition approach for high-density surface electromyography and was tested with two experimental studies for reliability and sensitivity. Experiment I (reliability): ten participants performed isometric knee extensions at 10, 30, 50 and 70\% of their maximum voluntary contraction (MVC) force in three sessions, each separated by 1 week. Experiment II (sensitivity): seven participants performed 2 weeks of endurance training (cycling) and were tested pre-post intervention during isometric knee extensions at 10 and 30\% MVC. The reliability (Experiment I) and sensitivity (Experiment II) of the measured MU properties were compared for the MUs tracked across sessions, with respect to all MUs identified in each session. In Experiment I, on average 38.3\% and 40.1\% of the identified MUs could be tracked across two sessions (1 and 2 weeks apart), for the vastus medialis and vastus lateralis, respectively. Moreover, the properties of the tracked MUs were more reliable across sessions than those of the full set of identified MUs (intra-class correlation coefficients ranged between 0.63-0.99 and 0.39-0.95, respectively). In Experiment II, similar to 40\% of the MUs could be tracked before and after the training intervention and training-induced changes in MU conduction velocity had an effect size of 2.1 (tracked MUs) and 1.5 (group of all identified motor units). These results show the possibility of monitoring MU properties longitudinally to document the effect of interventions or the progression of neuromuscular disorders.},
  language  = {en}
}
@article{MuellerStollMuelleretal.2017,
  author    = {M{\"u}ller, Steffen and Stoll, Josefine and Mueller, Juliane and Cassel, Michael and Mayer, Frank},
  title     = {Trunk Muscle Activity during Drop Jump Performance in Adolescent Athletes with Back Pain},
  series = {Frontiers in physiology},
  volume    = {8},
  journal   = {Frontiers in physiology},
  publisher = {Frontiers Research Foundation},
  address   = {Lausanne},
  issn      = {1664-042X},
  doi       = {10.3389/fphys.2017.00274},
  pages     = {124 -- 132},
  year      = {2017},
  abstract  = {In the context of back pain, great emphasis has been placed on the importance of trunk stability, especially in situations requiring compensation of repetitive, intense loading induced during high-performance activities, e.g., jumping or landing. This study aims to evaluate trunk muscle activity during drop jump in adolescent athletes with back pain (BP) compared to athletes without back pain (NBP). Eleven adolescent athletes suffering back pain (BP: m/f: n = 4/7; 15.9 +/- 1.3 y; 176 +/- 11 cm; 68 +/- 11 kg; 12.4 +/- 10.5 h/we training) and 11 matched athletes without back pain (NBP: m/f: n = 4/7; 15.5 +/- 1.3 y; 174 +/- 7 cm; 67 +/- 8 kg; 14.9 +/- 9.5 h/we training) were evaluated. Subjects conducted 3 drop jumps onto a force plate (ground reaction force). Bilateral 12-lead SEMG (surface Electromyography) was applied to assess trunk muscle activity. Ground contact time [ms], maximum vertical jump force [N], jump time [ms] and the jump performance index [m/s] were calculated for drop jumps. SEMG amplitudes (RMS: root mean square [\%]) for all 12 single muscles were normalized toMIVC (maximum isometric voluntary contraction) and analyzed in 4 time windows (100 ms pre- and 200 ms post-initial ground contact, 100 ms pre- and 200 ms post-landing) as outcome variables. In addition, muscles were grouped and analyzed in ventral and dorsal muscles, as well as straight and transverse trunk muscles. Drop jump ground reaction force variables did not differ between NBP and BP (p > 0.05). Mm obliquus externus and internus abdominis presented higher SEMG amplitudes (1.3-1.9-fold) for BP (p < 0.05). Mm rectus abdominis, erector spinae thoracic/lumbar and latissimus dorsi did not differ (p > 0.05). The muscle group analysis over the whole jumping cycle showed statistically significantly higher SEMG amplitudes for BP in the ventral (p = 0.031) and transverse muscles (p = 0.020) compared to NBP. Higher activity of transverse, but not straight, trunk muscles might indicate a specific compensation strategy to support trunk stability in athletes with back pain during drop jumps. Therefore, exercises favoring the transverse trunk muscles could be recommended for back pain treatment.},
  language  = {en}
}