@article{SchomoellerRischKaplicketal.2021,
  author    = {Schom{\"o}ller, Anne and Risch, Lucie and Kaplick, Hannes and Wochatz, Monique and Engel, Tilman and Schraplau, Anne and Sonnenburg, Dominik and Huppertz, Alexander and Mayer, Frank},
  title     = {Inter-rater and inter-session reliability of lumbar paraspinal muscle composition in a mobile MRI device},
  series = {BJR : an international journal of radiology, radiation oncology and all related sciences / British Institute of Radiology},
  volume    = {94},
  journal   = {BJR : an international journal of radiology, radiation oncology and all related sciences / British Institute of Radiology},
  number    = {1127},
  publisher = {Wiley},
  address   = {Bognor Regis},
  issn      = {0007-1285},
  doi       = {10.1259/bjr.20210141},
  pages     = {6},
  year      = {2021},
  abstract  = {Objective: To assess the reliability of measurements of paraspinal muscle transverse relaxation times (T2 times) between two observers and within one observer on different time points. <br /> Methods: 14 participants (9f/5m, 33 +/- 5 years, 176 +/- 10 cm, 73 +/- 12 kg) underwent 2 consecutive MRI scans (M1,M2) on the same day, followed by 1 MRI scan 13-14 days later (M3) in a mobile 1.5 Tesla MRI. T2 times were calculated in T-2 weighted turbo spin- echo-sequences at the spinal level of the third lumbar vertebrae (11 slices, 2 mm slice thickness, 1 mm interslice gap, echo times: 20, 40, 60, 80, 100 ms) for M. erector spinae (ES) and M. multifidius (MF). The following reliability parameter were calculated for the agreement of T2 times between two different investigators (OBS1 \& OBS2) on the same MRI (inter rater reliability, IR) and by one investigator between different MRI of the same participant (intersession variability, IS): Test-Retest Variability (TRV, Differences/Mean*100); Coefficient of Variation (CV, Standard deviation/Mean*100); Bland-Altman Analysis (systematic bias = Mean of the Differences; Upper/Lower Limits of Agreement = Bias+/-1.96*SD); Intraclass Correlation Coefficient 3.1 (ICC) with absolute agreement, as well as its 95\% confidence interval. <br /> Results: Mean TRV for IR was 2.6\% for ES and 4.2\% for MF. Mean TRV for IS was 3.5\% (ES) and 5.1\% (MF). Mean CV for IR was 1.9 (ES) and 3.0 (MF). Mean CV for IS was 2.5\% (ES) and 3.6\% (MF). A systematic bias of 1.3 ms (ES) and 2.1 ms (MF) were detected for IR and a systematic bias of 0.4 ms (ES) and 0.07 ms (MF) for IS. ICC for IR was 0.94 (ES) and 0.87 (MF). ICC for IS was 0.88 (ES) and 0.82 (MF). <br /> Conclusion: Reliable assessment of paraspinal muscle T2 time justifies its use for scientific purposes. The applied technique could be recommended to use for future studies that aim to assess changes of T2 times, e.g. after an intense bout of eccentric exercises.},
  language  = {en}
}
@article{HenschkeKaplickWochatzetal.2022,
  author    = {Henschke, Jakob and Kaplick, Hannes and Wochatz, Monique and Engel, Tilman},
  title     = {Assessing the validity of inertial measurement units for shoulder kinematics using a commercial sensor-software system},
  series = {Health science reports},
  volume    = {5},
  journal   = {Health science reports},
  number    = {5},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {2398-8835},
  doi       = {10.1002/hsr2.772},
  pages     = {1 -- 11},
  year      = {2022},
  abstract  = {Background and Aims Wearable inertial sensors may offer additional kinematic parameters of the shoulder compared to traditional instruments such as goniometers when elaborate and time-consuming data processing procedures are undertaken. However, in clinical practice simple-real time motion analysis is required to improve clinical reasoning. Therefore, the aim was to assess the criterion validity between a portable "off-the-shelf" sensor-software system (IMU) and optical motion (Mocap) for measuring kinematic parameters during active shoulder movements. Methods 24 healthy participants (9 female, 15 male, age 29 +/- 4 years, height 177 +/- 11 cm, weight 73 +/- 14 kg) were included. Range of motion (ROM), total range of motion (TROM), peak and mean angular velocity of both systems were assessed during simple (abduction/adduction, horizontal flexion/horizontal extension, vertical flexion/extension, and external/internal rotation) and complex shoulder movements. Criterion validity was determined using intraclass-correlation coefficients (ICC), root mean square error (RMSE) and Bland and Altmann analysis (bias; upper and lower limits of agreement). Results ROM and TROM analysis revealed inconsistent validity during simple (ICC: 0.040-0.733, RMSE: 9.7 degrees-20.3 degrees, bias: 1.2 degrees-50.7 degrees) and insufficient agreement during complex shoulder movements (ICC: 0.104-0.453, RMSE: 10.1 degrees-23.3 degrees, bias: 1.0 degrees-55.9 degrees). Peak angular velocity (ICC: 0.202-0.865, RMSE: 14.6 degrees/s-26.7 degrees/s, bias: 10.2 degrees/s-29.9 degrees/s) and mean angular velocity (ICC: 0.019-0.786, RMSE:6.1 degrees/s-34.2 degrees/s, bias: 1.6 degrees/s-27.8 degrees/s) were inconsistent. Conclusions The "off-the-shelf" sensor-software system showed overall insufficient agreement with the gold standard. Further development of commercial IMU-software-solutions may increase measurement accuracy and permit their integration into everyday clinical practice.},
  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. <br /> 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). <br /> 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{EngelSchraplauWochatzetal.2021,
  author    = {Engel, Tilman and Schraplau, Anne and Wochatz, Monique and Kopinski, Stephan and Sonnenburg, Dominik and Schom{\"o}ller, Anne and Risch, Lucie and Kaplick, Hannes and Mayer, Frank},
  title     = {Feasability of An Eccentric Isokinetic Protocol to Induce Trunk Muscle Damage: A Pilot Study},
  series = {Sports Medicine International Open},
  volume    = {6},
  journal   = {Sports Medicine International Open},
  edition   = {1},
  publisher = {Thieme},
  address   = {Stuttgart},
  issn      = {2367-1890},
  doi       = {10.1055/a-1757-6724},
  pages     = {E9 -- E17},
  year      = {2021},
  abstract  = {Eccentric exercise is discussed as a treatment option for clinical populations, but specific responses in terms of muscle damage and systemic inflammation after repeated loading of large muscle groups have not been conclusively characterized. Therefore, this study tested the feasibility of an isokinetic protocol for repeated maximum eccentric loading of the trunk muscles. Nine asymptomatic participants (5 f/4 m; 34±6 yrs; 175±13 cm; 76±17 kg) performed three isokinetic 2-minute all-out trunk strength tests (1x concentric (CON), 2x eccentric (ECC1, ECC2), 2 weeks apart; flexion/extension, 60°/s, ROM 55°). Outcomes were peak torque, torque decline, total work, and indicators of muscle damage and inflammation (over 168 h). Statistics were done using the Friedman test (Dunn's post-test). For ECC1 and ECC2, peak torque and total work were increased and torque decline reduced compared to CON. Repeated ECC bouts yielded unaltered torque and work outcomes. Muscle damage markers were highest after ECC1 (soreness 48 h, creatine kinase 72 h; p<0.05). Their overall responses (area under the curve) were abolished post-ECC2 compared to post-ECC1 (p<0.05). Interleukin-6 was higher post-ECC1 than CON, and attenuated post-ECC2 (p>0.05). Interleukin-10 and tumor necrosis factor-α were not detectable. All markers showed high inter-individual variability. The protocol was feasible to induce muscle damage indicators after exercising a large muscle group, but the pilot results indicated only weak systemic inflammatory responses in asymptomatic adults.},
  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}
}
@article{CasselRischMayeretal.2019,
  author    = {Cassel, Michael and Risch, Lucie and Mayer, Frank and Kaplick, Hannes and Engel, Aaron and Kulig, Kornelia and Bashford, Greg},
  title     = {Achilles tendon morphology assessed using image based spatial frequency analysis is altered among healthy elite adolescent athletes compared to recreationally active controls},
  series = {Journal of science and medicine in sport : official journal of Sports Medicine Australia},
  volume    = {22},
  journal   = {Journal of science and medicine in sport : official journal of Sports Medicine Australia},
  number    = {8},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {1440-2440},
  doi       = {10.1016/j.jsams.2019.03.011},
  pages     = {882 -- 886},
  year      = {2019},
  abstract  = {Objectives: Although expected, tendon adaptations in adolescent elite athletes have been underreported. Morphologically, adaptations may occur by an increase in collagen fiber density and/or organization. These characteristics can be captured using spatial frequency parameters extracted from ultrasound images. This study aims to compare Achilles tendon (AT) morphology among sports-specific cohorts of elite adolescent athletes and to compare these findings to recreationally active controls by use of spatial frequency analysis. Design: Cross-sectional observational study. Method: In total, 334 healthy adolescent athletes from four sport categories (ball, combat, endurance, explosive strength) and 35 healthy controls were included. Longitudinal ultrasound scans were performed at the AT insertion and midportion. Intra-tendinous-morphology was quantified by performing spatial frequency analysis assessing eight parameters at standardized ROls. Increased values in five parameters suggest a higher structural organization, and in two parameters higher fiber density. One parameter represents a quotient combining both organization and fiber density. Results: Among athletes, only ball sport athletes exhibited an increase in one summative parameter at pre-insertion site compared to athletes from other sport categories. When compared to athletes, controls had significantly higher values of four parameters at pre-insertion and three parameters at midportion site reflecting differences in both, fiber organization and density. Conclusions: Intra-tendinous-morphology was similar in all groups of adolescent athletes. Higher values found in non-athletes might suggest higher AT fiber density and organization. It is yet unclear whether the lesser structural organization in young athletes represents initial AT pathology, or a physiological adaptive response at the fiber cross-linking level. (C) 2019 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.},
  language  = {en}
}
@article{IntziegianniCasselRaufetal.2016,
  author    = {Intziegianni, Konstantina and Cassel, Michael and Rauf, S. and White, S. and Rector, Michael V. and Kaplick, Hannes and Wahmkow, Gunnar and Kratzenstein, S. and Mayer, Frank},
  title     = {Influence of Age and Pathology on Achilles Tendon Properties During a Single-leg Jump},
  series = {International journal of sports medicine},
  volume    = {37},
  journal   = {International journal of sports medicine},
  publisher = {Thieme},
  address   = {Stuttgart},
  issn      = {0172-4622},
  doi       = {10.1055/s-0042-108198},
  pages     = {973 -- 978},
  year      = {2016},
  abstract  = {Prevalence of Achilles tendinopathy increases with age leading to a weaker tendon with predisposition to rupture. Conclusive evidence of the influence of age and pathology on Achilles tendon (AT) properties remains limited, as previous studies are based on standardized isometric conditions. The study investigates the influence of age and pathology on AT properties during single-leg vertical jump (SLVJ). 10 children (C), 10 asymptomatic adults (A), and 10 tendinopathic patients (T) were included. AT elongation [mm] from rest to maximal displacement during a SLVJ on a force-plate was sonographically assessed. AT compliance [mm/N]) and strain [\%] was calculated by dividing elongation by peak ground reaction force [N] and length, respectively. One-way ANOVA followed by Bonferroni post-hoc correction (=0.05) were used to compare C with A and A with T. AT elongation (p=0.004), compliance (p=0.001), and strain were found to be statistically significant higher in C (27 +/- 3mm, 0.026 +/- 0.006[mm/N], 13 +/- 2\%) compared to A (21 +/- 4mm, 0.017 +/- 0.005[mm/N], 10 +/- 2\%). No statistically significant differences (p0.05) was found between A and T (25 +/- 5mm, 0.019 +/- 0.004[mm/N], 12 +/- 3\%). During SLVJ, tendon responded differently in regards to age and pathology with children having the most compliant AT. Higher compliance found in healthy tendons might be considered as a protective factor against load-related injuries.},
  language  = {en}
}