Publications by authors named "Frank Mayer"

141 Publications

The effect of chronic ankle instability on muscle activations in lower extremities.

PLoS One 2021 22;16(2):e0247581. Epub 2021 Feb 22.

Outpatient Clinic, University of Potsdam, Potsdam, Germany.

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.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0247581PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7899370PMC
February 2021

Scapular kinematics during unloaded and maximal loaded isokinetic concentric and eccentric shoulder flexion and extension movements.

J Electromyogr Kinesiol 2021 Jan 17;57:102517. Epub 2021 Jan 17.

University of Potsdam, University Outpatient Clinic, Sports Medicine and Sports Orthopaedics, Am Neuen Palais 10 - Haus 12, D-14469 Potsdam, Germany. Electronic address:

Characterization of scapular kinematics under demanding load conditions might aid to distinguish between physiological and clinically relevant alterations. Previous investigations focused only on submaximal external load situations. How scapular movement changes with maximal load remains unclear. Therefore, the present study aimed to evaluate 3D scapular kinematics during unloaded and maximal loaded shoulder flexion and extension. Twelve asymptomatic individuals performed shoulder flexion and extension movements under unloaded and maximal concentric and eccentric loaded isokinetic conditions. 3D scapular kinematics assessed with a motion capture system was analyzed for 20° intervals of humeral positions from 20° to 120° flexion. Repeated measures ANOVAs were used to evaluate kinematic differences between load conditions for scapular position angles, scapulohumeral rhythm and scapular motion extent. Increased scapular upward rotation was seen during shoulder flexion and extension as well as decreased posterior tilt and external rotation during eccentric and concentric arm descents of maximal loaded compared to unloaded conditions. Load effects were further seen for the scapulohumeral rhythm with greater scapular involvement at lower humeral positions and increased scapular motion extent under maximal loaded shoulder movements. With maximal load applied to the arm physiological scapular movement pattern are induced that may imply both impingement sparing and causing mechanisms.
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http://dx.doi.org/10.1016/j.jelekin.2021.102517DOI Listing
January 2021

Local blood coagulation drives cancer cell arrest and brain metastasis in a mouse model.

Blood 2021 Mar;137(9):1219-1232

Neurology Clinic and National Center for Tumor Diseases, University Hospital Heidelberg, Heidelberg, Germany.

Clinically relevant brain metastases (BMs) frequently form in cancer patients, with limited options for effective treatment. Circulating cancer cells must first permanently arrest in brain microvessels to colonize the brain, but the critical factors in this process are not well understood. Here, in vivo multiphoton laser-scanning microscopy of the entire brain metastatic cascade allowed unprecedented insights into how blood clot formation and von Willebrand factor (VWF) deposition determine the arrest of circulating cancer cells and subsequent brain colonization in mice. Clot formation in brain microvessels occurred frequently (>95%) and specifically at intravascularly arrested cancer cells, allowing their long-term arrest. An extensive clot embedded ∼20% of brain-arrested cancer cells, and those were more likely to successfully extravasate and form a macrometastasis. Mechanistically, the generation of tissue factor-mediated thrombin by cancer cells accounted for local activation of plasmatic coagulation in the brain. Thrombin inhibition by treatment with low molecular weight heparin or dabigatran and an anti-VWF antibody prevented clot formation, cancer cell arrest, extravasation, and the formation of brain macrometastases. In contrast, tumor cells were not able to directly activate platelets, and antiplatelet treatments did reduce platelet dispositions at intravascular cancer cells but did not reduce overall formation of BMs. In conclusion, our data show that plasmatic coagulation is activated early by intravascular tumor cells in the brain with subsequent clot formation, which led us to discover a novel and specific mechanism that is crucial for brain colonization. Direct or indirect thrombin and VWF inhibitors emerge as promising drug candidates for trials on prevention of BMs.
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http://dx.doi.org/10.1182/blood.2020005710DOI Listing
March 2021

Motor Control Stabilisation Exercise for Patients with Non-Specific Low Back Pain: A Prospective Meta-Analysis with Multilevel Meta-Regressions on Intervention Effects.

J Clin Med 2020 Sep 22;9(9). Epub 2020 Sep 22.

University Outpatient Clinic, Centre of Sports Medicine, University of Potsdam, 14469 Potsdam, Germany.

Low-to-moderate quality meta-analytic evidence shows that motor control stabilisation exercise (MCE) is an effective treatment of non-specific low back pain. A possible approach to overcome the weaknesses of traditional meta-analyses would be that of a prospective meta-analyses. The aim of the present analysis was to generate high-quality evidence to support the view that motor control stabilisation exercises (MCE) lead to a reduction in pain intensity and disability in non-specific low back pain patients when compared to a control group. In this prospective meta-analysis and sensitivity multilevel meta-regression within the MiSpEx-Network, 18 randomized controlled study arms were included. Participants with non-specific low back pain were allocated to an intervention (individualized MCE, 12 weeks) or a control group (no additive exercise intervention). From each study site/arm, outcomes at baseline, 3 weeks, 12 weeks, and 6 months were pooled. The outcomes were current pain (NRS or VAS, 11 points scale), characteristic pain intensity, and subjective disability. A random effects meta-analysis model for continuous outcomes to display standardized mean differences between intervention and control was performed, followed by sensitivity multilevel meta-regressions. Overall, 2391 patients were randomized; 1976 (3 weeks, short-term), 1740 (12 weeks, intermediate), and 1560 (6 months, sustainability) participants were included in the meta-analyses. In the short-term, intermediate and sustainability, moderate-to-high quality evidence indicated that MCE has a larger effect on current pain (SMD = -0.15, -0.15, -0.19), pain intensity (SMD = -0.19, -0.26, -0.26) and disability (SMD = -0.15, -0.27, -0.25) compared with no exercise intervention. Low-quality evidence suggested that those patients with comparably intermediate current pain and older patients may profit the most from MCE. Motor control stabilisation exercise is an effective treatment for non-specific low back pain. Sub-clinical intermediate pain and middle-aged patients may profit the most from this intervention.
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http://dx.doi.org/10.3390/jcm9093058DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564352PMC
September 2020

Overexpression of Gjb4 impairs cell proliferation and insulin secretion in primary islet cells.

Mol Metab 2020 11 18;41:101042. Epub 2020 Jun 18.

Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, D-14558, Nuthetal, Germany; German Center for Diabetes Research (DZD), Ingolstädter Landstraße 1, D-85764, München-Neuherberg, Germany; Molecular and Clinical Life Science of Metabolic Diseases, University of Potsdam, Arthur-Scheunert-Allee 114-116, D-14558, Nuthetal, Germany. Electronic address:

Objective: Altered gene expression contributes to the development of type 2 diabetes (T2D); thus, the analysis of differentially expressed genes between diabetes-susceptible and diabetes-resistant mouse models is an important tool for the determination of candidate genes that participate in the pathology. Based on RNA-seq and array data comparing pancreatic gene expression of diabetes-prone New Zealand Obese (NZO) mice and diabetes-resistant B6.V-ob/ob (B6-ob/ob) mice, the gap junction protein beta 4 (Gjb4) was identified as a putative novel T2D candidate gene.

Methods: Gjb4 was overexpressed in primary islet cells derived from C57BL/6 (B6) mice and INS-1 cells via adenoviral-mediated infection. The proliferation rate of cells was assessed by BrdU incorporation, and insulin secretion was measured under low (2.8 mM) and high (20 mM) glucose concentration. INS-1 cell apoptosis rate was determined by Western blotting assessing cleaved caspase 3 levels.

Results: Overexpression of Gjb4 in primary islet cells significantly inhibited the proliferation by 47%, reduced insulin secretion of primary islets (46%) and INS-1 cells (51%), and enhanced the rate of apoptosis by 63% in INS-1 cells. Moreover, an altered expression of the miR-341-3p contributes to the Gjb4 expression difference between diabetes-prone and diabetes-resistant mice.

Conclusions: The gap junction protein Gjb4 is highly expressed in islets of diabetes-prone NZO mice and may play a role in the development of T2D by altering islet cell function, inducing apoptosis and inhibiting proliferation.
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http://dx.doi.org/10.1016/j.molmet.2020.101042DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7365933PMC
November 2020

Cross-cultural adaptation, reliability, and validation of the Taiwan-Chinese version of Cumberland Ankle Instability Tool.

Disabil Rehabil 2020 Jun 15:1-7. Epub 2020 Jun 15.

Sociology of Health and Physical Activity, University of Potsdam, Potsdam, Germany.

To cross-cultural translate the Cumberland Ankle Instability Tool (CAIT) to Taiwan-Chinese version (CAIT-TW), and to evaluate the validity, reliability and cutoff score of CAIT-TW for Taiwan-Chinese athletic population. The English version of CAIT was translated to CAIT-TW based on a guideline of cross-cultural adaptation. 77 and 58 Taiwanese collegial athletes with and without chronic ankle instability filled out CAIT-TW, Taiwan-Chinese version of Lower Extremity Functional Score (LEFS-TW) and Numeric Rating Scale (NRS). The construct validity, test-retest reliability, internal consistency and cutoff score of CAIT-TW were evaluated. In construct validity, the Spearman's correlation coefficients were moderate (CAIT-TW vs LEFS-TW: Rho = 0.39,  < 0.001) and strong (CAIT-TW vs NRS: Rho= 0.76,  < 0.001). The test retest reliability was excellent (ICC = 0.91, 95% confidential interval = 0.87-0.94,  < 0.001) with a good internal consistency (Cronbach's α: 0.87). Receiver operating characteristic curve showed a cutoff score of 21.5 (Youden index: 0.73, sensitivity: 0.87, specificity 0.85). The CAIT-TW is a valid and reliable tool to differentiate between stable and instable ankles in athletes and may further apply for research or daily practice in Taiwan.Implications for rehabilitationFor athletes, chronic ankle instability is prevalent and causes negative sequela, such as lowered quality of daily life, affected functional performance, and may cause post traumatic osteoarthritis.The psychometric properties of the Taiwan-Chinese version of the Cumberland Ankle Instability Tool showed moderate to strong construct validity, excellent test retest reliability, a good internal consistency and a cutoff score of 21.5.The validity and reliability of the Taiwan-Chinese version of the Cumberland Ankle Instability Tool are to enable clinicians to evaluate and manage ankle instability in Taiwanese who speaks Mandarin Chinese.
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http://dx.doi.org/10.1080/09638288.2020.1774928DOI Listing
June 2020

Personalized Treatment Suggestions: The Validity and Applicability of the Risk-Prevention-Index Social in Low Back Pain Exercise Treatments.

J Clin Med 2020 Apr 22;9(4). Epub 2020 Apr 22.

University Outpatient Clinic, Centre of Sports Medicine, University of Potsdam, 14469 Potsdam, Germany.

The back pain screening tool Risk-Prevention-ndex ocial (RPI-S) identifies the individual psychosocial risk for low back pain chronification and supports the allocation of patients at risk in additional multidisciplinary treatments. The study objectives were to evaluate (1) the prognostic validity of the RPI-S for a 6-month time frame and (2) the clinical benefit of the RPI-S. In a multicenter single-blind 3-armed randomized controlled trial, = 660 persons (age 18-65 years) were randomly assigned to a twelve-week uni- or multidisciplinary exercise intervention or control group. Psychosocial risk was assessed by the RPI-S domain social environment (RPI-S) and the outcome pain by the Chronic Pain Grade Questionnaire (baseline M1, 12-weeks M4, 24-weeks M5). Prognostic validity was quantified by the root mean squared error (RMSE) within the control group. The clinical benefit of RPI-S was calculated by repeated measures ANOVA in intervention groups. A subsample of = 274 participants (mean = 38.0 years, SD 13.1) was analyzed, of which 30% were classified at risk in their psychosocial profile. The half-year prognostic validity was good (RMSE for disability of 9.04 at M4 and of 9.73 at M5; RMSE for pain intensity of 12.45 at M4 and of 14.49 at M5). People at risk showed significantly stronger reduction in pain disability and intensity at M4/M5, if participating in a multidisciplinary exercise treatment. Subjects at no risk showed a smaller reduction in pain disability in both interventions and no group differences for pain intensity. Regarding disability due to pain, around 41% of the sample would gain an unfitted treatment without the back pain screening. The RPI-S prognostic validity demonstrated good applicability and a clinical benefit confirmed by a clear advantage of an individualized treatment possibility.
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http://dx.doi.org/10.3390/jcm9041197DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7230931PMC
April 2020

Stress and Self-Efficacy as Long-Term Predictors for Chronic Low Back Pain: A Prospective Longitudinal Study.

J Pain Res 2020 24;13:613-621. Epub 2020 Mar 24.

Sociology of Health and Physical Activity, University of Potsdam, Potsdam, Germany.

Purpose: Psychosocial variables are known risk factors for the development and chronification of low back pain (LBP). Psychosocial stress is one of these risk factors. Therefore, this study aims to identify the most important types of stress predicting LBP. Self-efficacy was included as a potential protective factor related to both, stress and pain.

Participants And Methods: This prospective observational study assessed n = 1071 subjects with low back pain over 2 years. Psychosocial stress was evaluated in a broad manner using instruments assessing perceived stress, stress experiences in work and social contexts, vital exhaustion and life-event stress. Further, self-efficacy and pain (characteristic pain intensity and disability) were assessed. Using least absolute shrinkage selection operator regression, important predictors of characteristic pain intensity and pain-related disability at 1-year and 2-years follow-up were analyzed.

Results: The final sample for the statistic procedure consisted of 588 subjects (age: 39.2 (±13.4) years; baseline pain intensity: 27.8 (±18.4); disability: 14.3 (±17.9)). In the 1-year follow-up, the stress types "tendency to worry", "social isolation", "work discontent" as well as vital exhaustion and negative life events were identified as risk factors for both pain intensity and pain-related disability. Within the 2-years follow-up, Lasso models identified the stress types "tendency to worry", "social isolation", "social conflicts", and "perceived long-term stress" as potential risk factors for both pain intensity and disability. Furthermore, "self-efficacy" ("internality", "self-concept") and "social externality" play a role in reducing pain-related disability.

Conclusion: Stress experiences in social and work-related contexts were identified as important risk factors for LBP 1 or 2 years in the future, even in subjects with low initial pain levels. Self-efficacy turned out to be a protective factor for pain development, especially in the long-term follow-up. Results suggest a differentiation of stress types in addressing psychosocial factors in research, prevention and therapy approaches.
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http://dx.doi.org/10.2147/JPR.S223893DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7125403PMC
March 2020

Neuromuscular shoulder activity during exercises with different combinations of stable and unstable weight mass.

BMC Sports Sci Med Rehabil 2020 26;12:21. Epub 2020 Mar 26.

1Clinical Exercise Science, Department Sports and Health Science Medicine, University Outpatient Clinic Potsdam, University of Potsdam, Am Neuen Palais 10, House 12, 14469 Potsdam, Germany.

Background: Recent shoulder injury prevention programs have utilized resistance exercises combined with different forms of instability, with the goal of eliciting functional adaptations and thereby reducing the risk of injury. However, it is still unknown how an unstable weight mass (UWM) affects the muscular activity of the shoulder stabilizers. Aim of the study was to assess neuromuscular activity of dynamic shoulder stabilizers under four conditions of stable and UWM during three shoulder exercises. It was hypothesized that a combined condition of weight with UWM would elicit greater activation due to the increased stabilization demand.

Methods: Sixteen participants (7 m/9 f) were included in this cross-sectional study and prepared with an EMG-setup for the: Mm. upper/lower trapezius (U.TA/L.TA), lateral deltoid (DE), latissimus dorsi (LD), serratus anterior (SA) and pectoralis major (PE). A maximal voluntary isometric contraction test (MVIC; 5 s.) was performed on an isokinetic dynamometer. Next, internal/external rotation (In/Ex), abduction/adduction (Ab/Ad) and diagonal flexion/extension (F/E) exercises (5 reps.) were performed with four custom-made-pipes representing different exercise conditions. First, the empty-pipe (P; 0.5 kg) and then, randomly ordered, water-filled-pipe (PW; 1 kg), weight-pipe (PG; 4.5 kg) and weight + water-filled-pipe (PWG; 4.5 kg), while EMG was recorded. Raw root-mean-square values (RMS) were normalized to MVIC (%MVIC). Differences between conditions for RMS%MVIC, scapular stabilizer (: U.TA/L.TA; U.TA/SA) and contraction (: concentric/eccentric) ratios were analyzed (paired t-test;  ≤ 0.05; Bonferroni adjusted α = 0.008).

Results: PWG showed significantly greater muscle activity for all exercises and all muscles except for PE compared to P and PW. Condition PG elicited muscular activity comparable to PWG ( > 0.008) with significantly lower activation of L.TA and SA in the In/Ex rotation. The ratio was significantly higher in PWG compared to P and PW. No significant differences were found for the ratio in all exercises and for all muscles.

Conclusion: Higher weight generated greater muscle activation whereas an UWM raised the neuromuscular activity, increasing the stabilization demands. Especially in the In/Ex rotation, an UWM increased the RMS%MVIC and ratio. This might improve training effects in shoulder prevention and rehabilitation programs.
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http://dx.doi.org/10.1186/s13102-020-00168-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7098120PMC
March 2020

Sudden gait perturbations elicit sex-specific neuromuscular trunk responses in persons with low back pain.

J Biomech 2020 03 16;102:109646. Epub 2020 Jan 16.

University Outpatient Clinic, Sports Medicine & Sports Orthopaedics, University of Potsdam, Potsdam, Germany.

Persons with low back pain (LBP) exhibit delayed trunk muscle onset and increased co-contractions as a response to quasi-static and dynamic sudden trunk loading in comparison to back-healthy controls. Although LBP is more prevalent in females, sex-specific responses have not been well documented. Therefore, the purpose was to explore sex-specific neuromuscular differences, to gait perturbation, in LBP patients. Twenty-nine LBP patients (12m/17f;31 ± 10yrs; 174 ± 12 cm; 71 ± 16 kg) walked on a split-belt treadmill at 1 m/s, while 15 right-sided random perturbations (treadmill-belt decelerating, 40 m/s, 50 ms duration; 200 ms after heel contact) were applied. Muscle activity was assessed using a 12-lead surface EMG (6 back/6 abdominal muscles; 4000 Hz). EMG-RMS [%] (0-200 ms after perturbation) was calculated and normalized to RMS of unperturbed gait for each muscle. Furthermore, muscle onsets (ms) were determined. Two-way ANOVA (factors: sex/muscle) was applied to account for sex differences in main outcomes. EMG-RMS (amplitudes; mean) ranged from 356% to 901% in males and 349% to 694% in females representing a significant interaction effect (sex * muscle: p = 0.017). Post-hoc analysis revealed significant differences for EMG-RMS analysis of rectus abdominis left (p = 0.043; f > m) as well as obliques externus right/left (p = 0.018/p = 0.005; f < m). In the time domain, females showed overall, shorter (mean: 90 ± 16 ms) response times compared to males (mean: 98 ± 22 ms, sex effect: p < 0.0001). In this LBP population, abdominal muscle activation discriminated females from males. Specifically, females had higher activity of the rectus abdominis muscles and lower activation of the externus oblique muscles. These different activation strategies might be relevant to the development of sex-specific intervention strategies.
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http://dx.doi.org/10.1016/j.jbiomech.2020.109646DOI Listing
March 2020

Randomised phase II trial of trofosfamide vs. doxorubicin in elderly patients with untreated metastatic soft-tissue sarcoma.

Eur J Cancer 2020 01 28;124:152-160. Epub 2019 Nov 28.

University Hospital, Medical Center II, Tuebingen, Germany.

Doxorubicin represents the standard first-line treatment for metastatic soft-tissue sarcoma. We assessed the efficacy and safety of trofosfamide in elderly patients. In this controlled phase II trial, we randomly (1:2) assigned 120 previously untreated patients with soft-tissue sarcoma, older than 60 years, with an Eastern Cooperative Oncology Group score of 0-2, to receive either doxorubicin for 6 cycles (arm A) or oral trofosfamide (arm B). The primary end-point was a 6-month progression-free rate (PFR) in the experimental arm (clinical trial information: NCT00204568). Between August 2004 and October 2012, forty and 80 patients were randomly assigned to arm A and arm B, respectively, in 16 centres. The median age was 70 years (range, 60-89). The primary study end-point (6-month PFR) was exceeded, with 27.6% in arm B (95% confidence interval [CI], 18.0-39.1) and 35.9% in arm A: (95% CI, 21.2-52.8). Survival data in terms of progression-free survival were 4.3 months (95% CI, 2.2-6.3) and 2.8 months (95% CI, 1.7-3.6) and in terms of overall survival were 9.8 months (95% CI, 6.7-11.6) and 12.3 months (95% CI, 9.6-16.2), respectively. The number of serious adverse event (SAE) was 59% in arm A and 30.3% in arm B (p = 0.005). Trofosfamide caused more often dyspnoea and low-grade fatigue, whereas with doxorubicin, more often leukocytopenia, neutropenia and mucositis were seen. Discontinuation rates for reasons other than disease progression were 15.4% (arm A) vs. 7.9% (arm B). In an elderly population of patients, oral trofosfamide achieved the estimated primary end-point 6-month PFR and was associated with a favourable toxicity profile compared with doxorubicin.
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http://dx.doi.org/10.1016/j.ejca.2019.10.016DOI Listing
January 2020

The feasibility of a split-belt instrumented treadmill running protocol with perturbations.

J Biomech 2020 01 9;98:109493. Epub 2019 Nov 9.

University of Potsdam, University Outpatient Clinic, Sports Medicine & Sports Orthopaedics, Potsdam, Germany.

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 = 28 ± 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.
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http://dx.doi.org/10.1016/j.jbiomech.2019.109493DOI Listing
January 2020

The Effectiveness of Telerehabilitation as a Supplement to Rehabilitation in Patients After Total Knee or Hip Replacement: Randomized Controlled Trial.

JMIR Rehabil Assist Technol 2019 Nov 7;6(2):e14236. Epub 2019 Nov 7.

Center of Rehabilitation Research, University of Potsdam, Potsdam, Germany.

Background: Telerehabilitation can contribute to the maintenance of successful rehabilitation regardless of location and time. The aim of this study was to investigate a specific three-month interactive telerehabilitation routine regarding its effectiveness in assisting patients with physical functionality and with returning to work compared to typical aftercare.

Objective: The aim of the study was to investigate a specific three-month interactive telerehabilitation with regard to effectiveness in functioning and return to work compared to usual aftercare.

Methods: From August 2016 to December 2017, 111 patients (mean 54.9 years old; SD 6.8; 54.3% female) with hip or knee replacement were enrolled in the randomized controlled trial. At discharge from inpatient rehabilitation and after three months, their distance in the 6-minute walk test was assessed as the primary endpoint. Other functional parameters, including health related quality of life, pain, and time to return to work, were secondary endpoints.

Results: Patients in the intervention group performed telerehabilitation for an average of 55.0 minutes (SD 9.2) per week. Adherence was high, at over 75%, until the 7th week of the three-month intervention phase. Almost all the patients and therapists used the communication options. Both the intervention group (average difference 88.3 m; SD 57.7; P=.95) and the control group (average difference 79.6 m; SD 48.7; P=.95) increased their distance in the 6-minute-walk-test. Improvements in other functional parameters, as well as in quality of life and pain, were achieved in both groups. The higher proportion of working patients in the intervention group (64.6%; P=.01) versus the control group (46.2%) is of note.

Conclusions: The effect of the investigated telerehabilitation therapy in patients following knee or hip replacement was equivalent to the usual aftercare in terms of functional testing, quality of life, and pain. Since a significantly higher return-to-work rate could be achieved, this therapy might be a promising supplement to established aftercare.

Trial Registration: German Clinical Trials Register DRKS00010009; https://www.drks.de/drks_web/navigate.do? navigationId=trial.HTML&TRIAL_ID=DRKS00010009.
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http://dx.doi.org/10.2196/14236DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6873150PMC
November 2019

Poly (ADP-Ribose) Polymerase-1 (PARP1) Deficiency and Pharmacological Inhibition by Pirenzepine Protects From Cisplatin-Induced Ototoxicity Without Affecting Antitumor Efficacy.

Front Cell Neurosci 2019 10;13:406. Epub 2019 Sep 10.

Department of Otorhinolaryngology, Head and Neck Surgery, Tübingen Hearing Research Center, University of Tübingen Medical Center, Tübingen, Germany.

Cisplatin remains an indispensable drug for the systemic treatment of many solid tumors. However, a major dose-limiting side-effect is ototoxicity. In some scenarios, such as treatment of germ cell tumors or adjuvant therapy of non-small cell lung cancer, cisplatin cannot be replaced without undue loss of efficacy. Inhibition of polyadenosine diphosphate-ribose polymerase-1 (PARP1), is presently being evaluated as a novel anti-neoplastic principle. Of note, cisplatin-induced PARP1 activation has been related to inner ear cell death. Thus, PARP1 inhibition may exert a protective effect on the inner ear without compromising the antitumor activity of cisplatin. Here, we evaluated PARP1 deficiency and PARP1 pharmacological inhibition as a means to protect the auditory hair cells from cisplatin-mediated ototoxicity. We demonstrate that cisplatin-induced loss of sensory hair cells in the organ of Corti is attenuated in PARP1-deficient cochleae. The PARP inhibitor pirenzepine and its metabolite LS-75 mimicked the protective effect observed in PARP1-deficient cochleae. Moreover, the cytotoxic potential of cisplatin was unchanged by PARP inhibition in two different cancer cell lines. Taken together, the results from our study suggest that the negative side-effects of cisplatin anti-cancer treatment could be alleviated by a PARP inhibition adjunctive therapy.
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http://dx.doi.org/10.3389/fncel.2019.00406DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6746891PMC
September 2019

General versus sports-specific injury prevention programs in athletes: A systematic review on the effects on performance.

PLoS One 2019 29;14(8):e0221346. Epub 2019 Aug 29.

University Outpatient Clinic, Professorship of Sports Medicine and Orthopedics, University of Potsdam, Potsdam, Germany.

Introduction: Injury prevention programs (IPPs) are an inherent part of training in recreational and professional sports. Providing performance-enhancing benefits in addition to injury prevention may help adjust coaches and athletes' attitudes towards implementation of injury prevention into daily routine. Conventional thinking by players and coaches alike seems to suggest that IPPs need to be specific to one's sport to allow for performance enhancement. The systematic literature review aims to firstly determine the IPPs nature of exercises and whether they are specific to the sport or based on general conditioning. Secondly, can they demonstrate whether general, sports-specific or even mixed IPPs improve key performance indicators with the aim to better facilitate long-term implementation of these programs?

Methods: PubMed and Web of Science were electronically searched throughout March 2018. The inclusion criteria were randomized control trials, publication dates between Jan 2006 and Feb 2018, athletes (11-45 years), injury prevention programs and included predefined performance measures that could be categorized into balance, power, strength, speed/agility and endurance. The methodological quality of included articles was assessed with the Cochrane Collaboration assessment tools.

Results: Of 6619 initial findings, 22 studies met the inclusion criteria. In addition, reference lists unearthed a further 6 studies, making a total of 28. Nine studies used sports specific IPPs, eleven general and eight mixed prevention strategies. Overall, general programs ranged from 29-57% in their effectiveness across performance outcomes. Mixed IPPs improved in 80% balance outcomes but only 20-44% in others. Sports-specific programs led to larger scale improvements in balance (66%), power (83%), strength (75%), and speed/agility (62%).

Conclusion: Sports-specific IPPs have the strongest influence on most performance indices based on the significant improvement versus control groups. Other factors such as intensity, technical execution and compliance should be accounted for in future investigations in addition to exercise modality.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0221346PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6715272PMC
March 2020

Orthopedic Injury Profiles in Adolescent Elite Athletes: A Retrospective Analysis From a Sports Medicine Department.

Front Physiol 2019 9;10:544. Epub 2019 May 9.

Outpatient Clinic, Sports Medicine and Orthopedics, University of Potsdam, Potsdam, Germany.

The aim of the study was to identify common orthopedic sports injury profiles in adolescent elite athletes with respect to age, sex, and anthropometrics. A retrospective data analysis of 718 orthopedic presentations among 381 adolescent elite athletes from 16 different sports to a sports medical department was performed. Recorded data of history and clinical examination included area, cause and structure of acute and overuse injuries. Injury-events were analyzed in the whole cohort and stratified by age (11-14/15-17 years) and sex. Group differences were tested by chi-squared-tests. Logistic regression analysis was applied examining the influence of factors age, sex, and body mass index (BMI) on the outcome variables area and structure (α = 0.05). Higher proportions of injury-events were reported for females (60%) and athletes of the older age group (66%) than males and younger athletes. The most frequently injured area was the lower extremity (47%) followed by the spine (30.5%) and the upper extremity (12.5%). Acute injuries were mainly located at the lower extremity (74.5%), while overuse injuries were predominantly observed at the lower extremity (41%) as well as the spine (36.5%). Joints (34%), muscles (22%), and tendons (21.5%) were found to be the most often affected structures. The injured structures were different between the age groups ( = 0.022), with the older age group presenting three times more frequent with ligament pathology events (5.5%/2%) and less frequent with bony problems (11%/20.5%) than athletes of the younger age group. The injured area differed between the sexes ( = 0.005), with males having fewer spine injury-events (25.5%/34%) but more upper extremity injuries (18%/9%) than females. Regression analysis showed statistically significant influence for BMI ( = 0.002) and age ( = 0.015) on structure, whereas the area was significantly influenced by sex ( = 0.005). Events of soft-tissue overuse injuries are the most common reasons resulting in orthopedic presentations of adolescent elite athletes. Mostly, the lower extremity and the spine are affected, while sex and age characteristics on affected area and structure must be considered. Therefore, prevention strategies addressing the injury-event profiles should already be implemented in early adolescence taking age, sex as well as injury entity into account.
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http://dx.doi.org/10.3389/fphys.2019.00544DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6520583PMC
May 2019

Achilles tendon morphology assessed using image based spatial frequency analysis is altered among healthy elite adolescent athletes compared to recreationally active controls.

J Sci Med Sport 2019 Aug 5;22(8):882-886. Epub 2019 Apr 5.

Department of Biological Systems Engineering, University of Nebraska-Lincoln, USA.

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 ROIs. 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.
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http://dx.doi.org/10.1016/j.jsams.2019.03.011DOI Listing
August 2019

Perioperative chemotherapy with fluorouracil plus leucovorin, oxaliplatin, and docetaxel versus fluorouracil or capecitabine plus cisplatin and epirubicin for locally advanced, resectable gastric or gastro-oesophageal junction adenocarcinoma (FLOT4): a randomised, phase 2/3 trial.

Lancet 2019 05 11;393(10184):1948-1957. Epub 2019 Apr 11.

Tagestherapiezentrum am ITM, III. Medizinische Klinik, Universitätsmedizin Mannheim, Mannheim, Germany.

Background: Docetaxel-based chemotherapy is effective in metastatic gastric and gastro-oesophageal junction adenocarcinoma. This study reports on the safety and efficacy of the docetaxel-based triplet FLOT (fluorouracil plus leucovorin, oxaliplatin and docetaxel) as a perioperative therapy for patients with locally advanced, resectable tumours.

Methods: In this controlled, open-label, phase 2/3 trial, we randomly assigned 716 patients with histologically-confirmed advanced clinical stage cT2 or higher or nodal positive stage (cN+), or both, resectable tumours, with no evidence of distant metastases, via central interactive web-based-response system, to receive either three pre-operative and three postoperative 3-week cycles of 50 mg/m epirubicin and 60 mg/m cisplatin on day 1 plus either 200 mg/m fluorouracil as continuous intravenous infusion or 1250 mg/m capecitabine orally on days 1 to 21 (ECF/ECX; control group) or four preoperative and four postoperative 2-week cycles of 50 mg/m docetaxel, 85 mg/m oxaliplatin, 200 mg/m leucovorin and 2600 mg/m fluorouracil as 24-h infusion on day 1 (FLOT; experimental group). The primary outcome of the trial was overall survival (superiority) analysed in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, number NCT01216644.

Findings: Between Aug 8, 2010, and Feb 10, 2015, 716 patients were randomly assigned to treatment in 38 German hospitals or with practice-based oncologists. 360 patients were assigned to ECF/ECX and 356 patients to FLOT. Overall survival was increased in the FLOT group compared with the ECF/ECX group (hazard ratio [HR] 0·77; 95% confidence interval [CI; 0.63 to 0·94]; median overall survival, 50 months [38·33 to not reached] vs 35 months [27·35 to 46·26]). The number of patients with related serious adverse events (including those occurring during hospital stay for surgery) was similar in the two groups (96 [27%] in the ECF/ECX group vs 97 [27%] in the FLOT group), as was the number of toxic deaths (two [<1%] in both groups). Hospitalisation for toxicity occurred in 94 patients (26%) in the ECF/ECX group and 89 patients (25%) in the FLOT group.

Interpretation: In locally advanced, resectable gastric or gastro-oesophageal junction adenocarcinoma, perioperative FLOT improved overall survival compared with perioperative ECF/ECX.

Funding: The German Cancer Aid (Deutsche Krebshilfe), Sanofi-Aventis, Chugai, and Stiftung Leben mit Krebs Foundation.
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http://dx.doi.org/10.1016/S0140-6736(18)32557-1DOI Listing
May 2019

Reliability and validity of the Kinect V2 for the assessment of lower extremity rehabilitation exercises.

Gait Posture 2019 05 26;70:330-335. Epub 2019 Mar 26.

University of Potsdam, University Outpatient Clinic, Sports Medicine & Sports Orthopaedics, Potsdam, Germany.

Background: Besides its initial use as a video gaming system the Kinect might also be suitable to capture human movements in the clinical context. However, the system's reliability and validity to capture rehabilitation exercises is unclear.

Research Question: The purpose of this study was to evaluate the test-retest reliability of lower extremity kinematics during squat, hip abduction and lunge exercises captured by the Kinect and to evaluate the agreement to a reference 3D camera-based motion system.

Methods: Twenty-one healthy individuals performed five repetitions of each lower limb exercise on two different days. Movements were simultaneously assessed by the Kinect and the reference 3D motion system. Joint angles and positions of the lower limb were calculated for sagittal and frontal plane. For the inter-session reliability and the agreement between the two systems standard error of measurement (SEM), bias with limits of agreement (LoA) and Pearson Correlation Coefficient (r) were calculated.

Results: Parameters indicated varying reliability for the assessed joint angles and positions and decreasing reliability with increasing task complexity. Across all exercises, measurement deviations were shown especially for small movement amplitudes. Variability was acceptable for joint angles and positions during the squat, partially acceptable during the hip abduction and predominately inacceptable during the lunge. The agreement between systems was characterized by systematic errors. Overestimations by the Kinect were apparent for hip flexion during the squat and hip abduction/adduction during the hip abduction exercise as well as for the knee positions during the lunge. Knee and hip flexion during hip abduction and lunge were underestimated by the Kinect.

Significance: The Kinect system can reliably assess lower limb joint angles and positions during simple exercises. The validity of the system is however restricted. An application in the field of early orthopedic rehabilitation without further development of post-processing techniques seems so far limited.
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http://dx.doi.org/10.1016/j.gaitpost.2019.03.020DOI Listing
May 2019

A phase I/IIa study of the mRNA-based cancer immunotherapy CV9201 in patients with stage IIIB/IV non-small cell lung cancer.

Cancer Immunol Immunother 2019 May 15;68(5):799-812. Epub 2019 Feb 15.

CureVac AG, Tübingen, Germany.

CV9201 is an RNActive-based cancer immunotherapy encoding five non-small cell lung cancer-antigens: New York esophageal squamous cell carcinoma-1, melanoma antigen family C1/C2, survivin, and trophoblast glycoprotein. In a phase I/IIa dose-escalation trial, 46 patients with locally advanced (n = 7) or metastatic (n = 39) NSCLC and at least stable disease after first-line treatment received five intradermal CV9201 injections (400-1600 µg of mRNA). The primary objective of the trial was to assess safety. Secondary objectives included assessment of antibody and ex vivo T cell responses against the five antigens, and changes in immune cell populations. All CV9201 dose levels were well-tolerated and the recommended dose for phase IIa was 1600 µg. Most AEs were mild-to-moderate injection site reactions and flu-like symptoms. Three (7%) patients had grade 3 related AEs. No related grade 4/5 or related serious AEs occurred. In phase IIa, antigen-specific immune responses against ≥ 1 antigen were detected in 63% of evaluable patients after treatment. The frequency of activated IgDCD38 B cells increased > twofold in 18/30 (60%) evaluable patients. 9/29 (31%) evaluable patients in phase IIa had stable disease and 20/29 (69%) had progressive disease. Median progression-free and overall survival were 5.0 months (95% CI 1.8-6.3) and 10.8 months (8.1-16.7) from first administration, respectively. Two- and 3-year survival rates were 26.7% and 20.7%, respectively. CV9201 was well-tolerated and immune responses could be detected after treatment supporting further clinical investigation.
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http://dx.doi.org/10.1007/s00262-019-02315-xDOI Listing
May 2019

Trunk peak torque, muscle activation pattern and sudden loading compensation in adolescent athletes with back pain.

J Back Musculoskelet Rehabil 2019 ;32(3):379-388

University Outpatient Clinic, Sports Medicine and Sports Orthopaedics, University of Potsdam, Potsdam, Germany.

Objective: To evaluate trunk peak torque and muscle activation pattern during isokinetic and sudden trunk loading (STL) between adolescent athletes with/without back pain.

Methods: Nine adolescent athletes with back pain (BP) (m/f 2/7; 15.6 ± 1.2 y; 177 ± 9 cm; 67 ± 13 kg; 22.5 ± 9.8 h/week) and nine matched controls (m/f 2/7; 15.7 ± 1.4 y; 177 ± 12 cm; 65 ± 9 kg; 16.5 ± 8.0 h/week training) were included. Trunk strength in rotation and flexion/extension was assessed. Sudden trunk loading was measured during eccentric extension and rotation (30∘/s) with additional perturbation. Trunk muscle activity was measured using a 12 lead-EMG (electromyography). Main outcome measures were peak torque [Nm] and MVC normalized EMG-amplitudes (RMS [%]) for each muscle. Additionally, the mean EMG-RMS for four areas of the trunk was calculated (right/left ventral, right/left dorsal).

Results: Back pain showed lower trunk peak torque for all conditions in extension/flexion, but not for rotation. EMG amplitudes were increased for BP athletes with statistical significant differences for dorsal muscles in rotation and extension (p< 0.0042), not for ventral muscles in flexion.

Conclusions: The evaluation of strength and muscle activity in isokinetic and sudden trunk loading presents altered trunk function in adolescent back pain athletes. Training interventions focusing on trunk strength and muscular activation pattern appears reasonable.
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http://dx.doi.org/10.3233/BMR-181215DOI Listing
August 2019

General versus sports-specific injury prevention programs in athletes: A systematic review on the effect on injury rates.

PLoS One 2018 19;13(10):e0205635. Epub 2018 Oct 19.

Department of Sport and Health Sciences, University Outpatient Clinic, University of Potsdam, Potsdam, Germany.

Introduction: Annually, 2 million sports-related injuries are reported in Germany of which athletes contribute to a large proportion. Multiple sport injury prevention programs designed to decrease acute and overuse injuries in athletes have been proven effective. Yet, the programs' components, general or sports-specific, that led to these positive effects are uncertain. Despite not knowing about the superiority of sports-specific injury prevention programs, coaches and athletes alike prefer more specialized rather than generalized exercise programs. Therefore, this systematic review aimed to present the available evidence on how general and sports-specific prevention programs affect injury rates in athletes.

Methods: PubMed and Web of Science were electronically searched throughout April 2018. The inclusion criteria were publication dates Jan 2006-Dec 2017, athletes (11-45 years), exercise-based injury prevention programs and injury incidence. The methodological quality was assessed with the Cochrane Collaboration assessment tools.

Results: Of the initial 6619 findings, 15 studies met the inclusion criteria. In addition, 13 studies were added from reference lists and external sources making a total of 28 studies. Of which, one used sports-specific, seven general and 20 mixed prevention strategies. Twenty-four studies revealed reduced injury rates. Of the four ineffective programs, one was general and three mixed.

Conclusion: The general and mixed programs positively affect injury rates. Sports-specific programs are uninvestigated and despite wide discussion regarding the definition, no consensus was reached. Defining such terminology and investigating the true effectiveness of such IPPs is a potential avenue for future research.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0205635PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6195266PMC
April 2019

Assessment of Dietary Intake of Long-Distance Race Car Drivers-A Pilot Study.

Sports (Basel) 2018 Oct 12;6(4). Epub 2018 Oct 12.

Center of Sports Medicine, University Outpatient Clinic Potsdam, University of Potsdam, 14469 Potsdam, Brandenburg, Germany.

Long-distance race car drivers are classified as athletes. The sport is physically and mentally demanding, requiring long hours of practice. Therefore, optimal dietary intake is essential for health and performance of the athlete. The aim of the study was to evaluate dietary intake and to compare the data with dietary recommendations for athletes and for the general adult population according to the German Nutrition Society (DGE). A 24-h dietary recall during a competition preparation phase was obtained from 16 male race car drivers (28.3 ± 6.1 years, body mass index (BMI) of 22.9 ± 2.3 kg/m²). The mean intake of energy, nutrients, water and alcohol was recorded. The mean energy, vitamin B₂, vitamin E, folate, fiber, calcium, water and alcohol intake were 2124 ± 814 kcal/day, 1.3 ± 0.5 mg/day, 12.5 ± 9.5 mg/day, 231.0 ± 90.9 ug/day, 21.4 ± 9.4 g/day, 1104 ± 764 mg/day, 3309 ± 1522 mL/day and 0.8 ± 2.5 mL/day respectively. Our study indicated that many of the nutrients studied, including energy and carbohydrate, were below the recommended dietary intake for both athletes and the DGE.
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http://dx.doi.org/10.3390/sports6040118DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6315910PMC
October 2018

Accuracy of training recommendations based on a treadmill multistage incremental exercise test.

PLoS One 2018 11;13(10):e0204696. Epub 2018 Oct 11.

Department of Sport and Health Sciences, Professorship of Sports Medicine and Orthopedics, University Outpatient Clinic, University of Potsdam, Potsdam, Germany.

Competitive runners will occasionally undergo exercise in a laboratory setting to obtain predictive and prescriptive information regarding their performance. The present research aimed to assess whether the physiological demands of lab-based treadmill running (TM) can simulate that of over-ground (OG) running using a commonly used protocol. Fifteen healthy volunteers with a weekly mileage of ≥ 20 km over the past 6 months and treadmill experience participated in this cross-sectional study. Two stepwise incremental tests until volitional exhaustion was performed in a fixed order within one week in an Outpatient Clinic research laboratory and outdoor athletic track. Running velocity (IATspeed), heart rate (IATHR) and lactate concentration at the individual anaerobic threshold (IATbLa) were primary endpoints. Additionally, distance covered (DIST), maximal heart rate (HRmax), maximal blood lactate concentration (bLamax) and rate of perceived exertion (RPE) at IATspeed were analyzed. IATspeed, DIST and HRmax were not statistically significantly different between conditions, whereas bLamax and RPE at IATspeed showed statistical significance (p < 0.05). Apart from RPE at IATspeed, IATspeed, DIST, HRmax and bLamax strongly correlate between conditions (r = 0.815-0.988). High reliability between conditions provides strong evidence to suggest that running on a treadmill are physiologically comparable to that of OG and that training recommendations and be made with assurance.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0204696PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6181318PMC
March 2019

Is in-toing gait physiological in children? - Results of a large cohort study in 5910 healthy (pre-) school children.

Gait Posture 2018 10 20;66:70-75. Epub 2018 Aug 20.

University of Potsdam, Department Sports and Health Sciences, Am Neuen Palais 10 Haus 12, 14471 Potsdam, Germany; Trier University of Applied Science, Department of Computer Science/Therapy Science, Schneiderhof Building L, 54293 Trier, Germany.

Background: In-toeing is a major concern of many parents presenting their children to pediatric orthopedists. Foot progression angle (FPA) quantifies the rotation of the foot's longitudinal axis during gait, with negative values describing in-toeing and positive values describing out-toeing. Although it has been shown that the FPA changes over the course of a child's development, reference values for the normal FPA-range are lacking.

Research Question: This study aimed to establish reference values in 1-14 year old healthy children and to implement FPA-percentile curves for daily clinical use.

Methods: 5910 healthy children performed at least 3 repetitions of barefoot walking over an instrumented walkway using a pressure measurement platform. The FPA [°] was extracted and analyzed by age and gender (mean ± standard deviation; median with percentiles, MANOVA (age, gender) and Wilcoxon-Signed-Rank test for intra-individual side differences (α = 0.05).

Results: FPA maximum was observed in 2-year-old children and diminished significant until the age of 4 to moderate out-toeing. For ages 5-14, no statistically significant differences in FPA values were present (p > 0.05). MANOVA confirmed age (p < 0.001) and gender (p < 0.001) as significant FPA influencing factors, without combined effect (p > 0.05). In every age group, right feet showed significantly greater out-toeing (p < 0.05).

Significance: Percentile values indicate a wide FPA range in children. FPA development in young children shows a spontaneous shift towards moderate external rotation (age 2-4), whereby in-toeing ≤ 1-5° can be present, but can return to normal. Bilateral in-toeing after the age of four and unilateral in-toeing after the age of seven should be monitored.
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http://dx.doi.org/10.1016/j.gaitpost.2018.08.019DOI Listing
October 2018

Dose-response relationship of core-specific sensorimotor interventions in healthy, well-trained participants: study protocol for a (MiSpEx) randomized controlled trial.

Trials 2018 Aug 6;19(1):424. Epub 2018 Aug 6.

University Outpatient Clinic, Sports Medicine and Sports Orthopaedics, University of Potsdam, Am Neuen Palais 10, House 12, 14469, Potsdam, Germany.

Background: Core-specific sensorimotor exercises are proven to enhance neuromuscular activity of the trunk, improve athletic performance and prevent back pain. However, the dose-response relationship and, therefore, the dose required to improve trunk function is still under debate. The purpose of the present trial will be to compare four different intervention strategies of sensorimotor exercises that will result in improved trunk function.

Methods/design: A single-blind, four-armed, randomized controlled trial with a 3-week (home-based) intervention phase and two measurement days pre and post intervention (M1/M2) is designed. Experimental procedures on both measurement days will include evaluation of maximum isokinetic and isometric trunk strength (extension/flexion, rotation) including perturbations, as well as neuromuscular trunk activity while performing strength testing. The primary outcome is trunk strength (peak torque). Neuromuscular activity (amplitude, latencies as a response to perturbation) serves as secondary outcome. The control group will perform a standardized exercise program of four sensorimotor exercises (three sets of 10 repetitions) in each of six training sessions (30 min duration) over 3 weeks. The intervention groups' programs differ in the number of exercises, sets per exercise and, therefore, overall training amount (group I: six sessions, three exercises, two sets; group II: six sessions, two exercises, two sets; group III: six sessions, one exercise, three sets). The intervention programs of groups I, II and III include additional perturbations for all exercises to increase both the difficulty and the efficacy of the exercises performed. Statistical analysis will be performed after examining the underlying assumptions for parametric and non-parametric testing.

Discussion: The results of the study will be clinically relevant, not only for researchers but also for (sports) therapists, physicians, coaches, athletes and the general population who have the aim of improving trunk function.

Trial Registration: German Clinical Trials Register, ID: DRKS00012917 . Registered on 22 August 2017.
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http://dx.doi.org/10.1186/s13063-018-2799-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6090836PMC
August 2018

Reproducibility of Static and Dynamic Postural Control Measurement in Adolescent Athletes with Back Pain.

Rehabil Res Pract 2018 2;2018:8438350. Epub 2018 Jul 2.

University Outpatient Clinic Potsdam, University of Potsdam, 14469 Potsdam, Brandenburg, Germany.

Static (one-legged stance) and dynamic (star excursion balance) postural control tests were performed by 14 adolescent athletes with and 17 without back pain to determine reproducibility. The total displacement, mediolateral and anterior-posterior displacements of the centre of pressure in mm for the static, and the normalized and composite reach distances for the dynamic tests were analysed. Intraclass correlation coefficients, 95% confidence intervals, and a Bland-Altman analysis were calculated for reproducibility. Intraclass correlation coefficients for subjects with (0.54 to 0.65), (0.61 to 0.69) and without (0.45 to 0.49), (0.52 to 0.60) back pain were obtained on the static test for right and left legs, respectively. Likewise, (0.79 to 0.88), (0.75 to 0.93) for subjects with and (0.61 to 0.82), (0.60 to 0.85) for those without back pain were obtained on the dynamic test for the right and left legs, respectively. Systematic bias was not observed between test and retest of subjects on both static and dynamic tests. The one-legged stance and star excursion balance tests have fair to excellent reliabilities on measures of postural control in adolescent athletes with and without back pain. They can be used as measures of postural control in adolescent athletes with and without back pain.
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http://dx.doi.org/10.1155/2018/8438350DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6051024PMC
July 2018

Impact of surgery in patients with metastatic soft tissue sarcoma: A monocentric retrospective analysis.

J Surg Oncol 2018 Jul 28;118(1):167-176. Epub 2018 Jun 28.

Department of Medical Oncology, Hematology, Immunology, Rheumatology and Pulmonology, University of Tübingen, Tübingen, Germany.

Background And Objectives: The role of local surgical procedures in patients with metastatic soft tissue sarcoma is still undefined. Few retrospective studies have reported survival benefits for patients with pulmonary metastases after complete surgical resection. Treatment decisions are therefore mainly based on personal experiences rather than on reproducible knowledge.

Method: A total of 237 patients with metastatic sarcoma, treated between 1982 and 2015 at the University Hospital Tuebingen, Germany, were eligible for inclusion. Out of the 237 screened patients, 102 patients underwent at least one metastasectomy. Overall survival was defined as the primary endpoint in this study. For association of non-linear relationship to the endpoint, significant prognostic factors were included into a recursive partitioning model. A subgroup analysis for long-term survivors was also performed.

Results: The median overall survival was 64 months. The 3-, 5-, 10-, and 20-years overall survival rates were 70.7%, 50.3%, 24.7%, and 14.8%, respectively. The number of resections and the progression-free intervals were independent prognostic factors in three statistical models.

Conclusion: Repeated resections of metastases from different localizations are a strong predictor for prolonged survival. We suggest that the progression-free interval after metastasectomy should be considered as a predictive factor for benefit from further surgery.
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http://dx.doi.org/10.1002/jso.25115DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6668010PMC
July 2018

Incidence of Achilles and Patellar Tendinopathy in Adolescent Elite Athletes.

Int J Sports Med 2018 Sep 25;39(9):726-732. Epub 2018 Jun 25.

Outpatient Clinic, Sports Medicine & Sports Orthopaedics, University of Potsdam, Potsdam, Germany.

The study investigated the incidence of Achilles and patellar tendinopathy in adolescent elite athletes and non-athletic controls. Furthermore, predictive and associated factors for tendinopathy development were analyzed. The prospective study consisted of two measurement days (M1/M2) with an interval of 3.2±0.9 years. 157 athletes (12.1±0.7 years) and 25 controls (13.3±0.6 years) without Achilles/patellar tendinopathy were included at M1. Clinical and ultrasound examinations of both Achilles (AT) and patellar tendons (PT) were performed. Main outcome measures were incidence tendinopathy and structural intratendinous alterations (hypo-/hyperechogenicity, vascularization) at M2 [%]. Incidence of Achilles tendinopathy was 1% in athletes and 0% in controls. Patellar tendinopathy was more frequent in athletes (13%) than in controls (4%). Incidence of intratendinous alterations in ATs was 1-2% in athletes and 0% in controls, whereas in PTs it was 4-6% in both groups (p>0.05). Intratendinous alterations at M2 were associated with patellar tendinopathy in athletes (p≤0.01). Intratendinous alterations at M1, anthropometric data, training amount, sports or sex did not predict tendinopathy development (p>0.05). Incidence of tendinopathy and intratendinous alterations in adolescent athletes is low in ATs and more common in PTs. Development of intratendinous alterations in PT is associated with tendinopathy. However, predictive factors could not be identified.
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http://dx.doi.org/10.1055/a-0633-9098DOI Listing
September 2018

Sensorimotor Exercises and Enhanced Trunk Function: A Randomized Controlled Trial.

Int J Sports Med 2018 Jul 18;39(7):555-563. Epub 2018 May 18.

University of Potsdam, University Outpatient Clinic, Sports Medicine & Sports Orthopaedics, Potsdam, Germany.

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.Forty-three healthy, well-trained participants were randomized into sensorimotor (SMT; n=11), resistance training (RT; n=16) and control groups (CG; n=16). Treatment groups received either sensorimotor training (SMT) or resistance training (RT) for 6 weeks, 3 times a week. At baseline and after 6 weeks of intervention, participants' maximum isokinetic strength in trunk rotation and extension was tested (concentric/eccentric 30°/s). In addition, sudden, high-intensity trunk loading was assessed for eccentric extension and rotation, with additional perturbation. Peak torque [Nm] was calculated as the outcome.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: +24 Nm 95%CI±19 Nm; Rotation: +19 Nm 95%CI±13 Nm) and RT (Extension: +35 Nm 95%CI±16 Nm; Rotation: +5 Nm 95%CI±4 Nm) compared to CG (Extension: -4 Nm 95%CI±16 Nm; Rotation: -2 Nm 95%CI±4 Nm) was present (p<0.05).This study showed that isokinetic strength gains were small, but that significant improvements in high-intensity trunk loading response could be shown for both interventions. Therefore, depending on the individual's preference, therapists have two treatment options to enhance trunk function for back pain prevention.
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http://dx.doi.org/10.1055/a-0592-7286DOI Listing
July 2018