@article{DechBittmannSchaefer2020,
  author    = {Dech, Silas and Bittmann, Frank and Schaefer, Laura},
  title     = {Behavior of oxygen saturation and blood filling in the venous capillary system of the biceps brachii muscle during a fatiguing isometric action},
  series = {European Journal of Translational Myology},
  volume    = {30},
  journal   = {European Journal of Translational Myology},
  number    = {1},
  publisher = {Unipress},
  address   = {Padova},
  issn      = {2037-7460},
  doi       = {10.4081/ejtm.2019.8800},
  pages     = {79 -- 87},
  year      = {2020},
  abstract  = {The objective of the study is to develop a better understanding of the capillary circulation in contracting muscles. Ten subjects were measured during a submaximal fatiguing isometric muscle action by use of the O2C spectrophotometer. In all measurements the capillary-venous oxygen saturation of hemoglobin (SvO2) decreases immediately after the start of loading and levels off into a steady state. However, two different patterns (type I and type II) emerged. They differ in the extent of deoxygenation (-10.37 ±2.59 percent points (pp) vs. -33.86 ±17.35 pp, P = .008) and the behavior of the relative hemoglobin amount (rHb). Type I reveals a positive rank correlation of SvO2 and rHb (? = 0.735, P <.001), whereas a negative rank correlation (? = -0.522, P <.001) occurred in type II, since rHb decreases until a reversal point, then increases averagely 13\% above the baseline value and levels off into a steady state. The results reveal that a homeostasis of oxygen delivery and consumption during isometric muscle actions is possible. A rough distinction in two types of regulation is suggested.},
  language  = {en}
}
@article{PuschmannDriessleinBecketal.2020,
  author    = {Puschmann, Anne-Katrin and Drießlein, David and Beck, Heidrun and Arampatzis, Adamantios and Moreno Catal{\´a}, Maria and Schiltenwolf, Marcus and Mayer, Frank and Wippert, Pia-Maria},
  title     = {Stress and Self-Efficacy as Long-Term Predictors for Chronic Low Back Pain},
  series = {Journal of Pain Research},
  volume    = {13},
  journal   = {Journal of Pain Research},
  publisher = {Dove Medical Press},
  address   = {Albany, Auckland},
  issn      = {1178-7090},
  doi       = {10.2147/JPR.S223893},
  pages     = {613 -- 621},
  year      = {2020},
  abstract  = {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.},
  language  = {en}
}
@article{MuellerStollMuelleretal.2018,
  author    = {Mueller, Juliane and Stoll, Josefine and Mueller, Steffen and Mayer, Frank},
  title     = {Dose-response relationship of core-specific sensorimotor interventions in healthy, welltrained participants},
  series = {Trials},
  volume    = {19},
  journal   = {Trials},
  number    = {424},
  publisher = {BioMed Central},
  address   = {London},
  issn      = {1745-6215},
  doi       = {10.1186/s13063-018-2799-9},
  pages     = {8},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}
@article{AppiahDwomohMuellerMayer2018,
  author    = {Appiah-Dwomoh, Edem Korkor and M{\"u}ller, Steffen and Mayer, Frank},
  title     = {Reproducibility of Static and Dynamic Postural Control Measurement in Adolescent Athletes with Back Pain},
  series = {Rehabilitation Research and Practice},
  volume    = {2018},
  journal   = {Rehabilitation Research and Practice},
  publisher = {Hindawi},
  address   = {New York},
  issn      = {2090-2875},
  doi       = {10.1155/2018/8438350},
  pages     = {1 -- 8},
  year      = {2018},
  abstract  = {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.},
  language  = {en}
}
@article{StelzelBohleSchauenburgetal.2018,
  author    = {Stelzel, Christine and Bohle, Hannah and Schauenburg, Gesche and Walter, Henrik and Granacher, Urs and Rapp, Michael A. and Heinzel, Stephan},
  title     = {Contribution of the Lateral Prefrontal Cortex to Cognitive-Postural Multitasking},
  series = {Frontiers in psychologie},
  volume    = {9},
  journal   = {Frontiers in psychologie},
  publisher = {Frontiers},
  address   = {Lausanne},
  issn      = {1664-1078},
  doi       = {10.3389/fpsyg.2018.01075},
  pages     = {12},
  year      = {2018},
  abstract  = {There is evidence for cortical contribution to the regulation of human postural control. Interference from concurrently performed cognitive tasks supports this notion, and the lateral prefrontal cortex (lPFC) has been suggested to play a prominent role in the processing of purely cognitive as well as cognitive-postural dual tasks. The degree of cognitive-motor interference varies greatly between individuals, but it is unresolved whether individual differences in the recruitment of specific lPFC regions during cognitive dual tasking are associated with individual differences in cognitive-motor interference. Here, we investigated inter-individual variability in a cognitive-postural multitasking situation in healthy young adults (n = 29) in order to relate these to inter-individual variability in lPFC recruitment during cognitive multitasking. For this purpose, a oneback working memory task was performed either as single task or as dual task in order to vary cognitive load. Participants performed these cognitive single and dual tasks either during upright stance on a balance pad that was placed on top of a force plate or during fMRI measurement with little to no postural demands. We hypothesized dual one-back task performance to be associated with lPFC recruitment when compared to single one-back task performance. In addition, we expected individual variability in lPFC recruitment to be associated with postural performance costs during concurrent dual one-back performance. As expected, behavioral performance costs in postural sway during dual-one back performance largely varied between individuals and so did lPFC recruitment during dual one-back performance. Most importantly, individuals who recruited the right mid-lPFC to a larger degree during dual one-back performance also showed greater postural sway as measured by larger performance costs in total center of pressure displacements. This effect was selective to the high-load dual one-back task and suggests a crucial role of the right lPFC in allocating resources during cognitivemotor interference. Our study provides further insight into the mechanisms underlying cognitive-motor multitasking and its impairments.},
  language  = {en}
}
@article{PerezChaparroZechSchuchetal.2018,
  author    = {P{\´e}rez Chaparro, Camilo Germ{\´a}n Alberto and Zech, Philipp and Schuch, Felipe and Wolfarth, Bernd and Rapp, Michael A. and Heiβel, Andreas},
  title     = {Effects of aerobic and resistance exercise alone or combined on strength and hormone outcomes for people living with HIV},
  series = {PLOS One},
  volume    = {13},
  journal   = {PLOS One},
  number    = {9},
  publisher = {PLOS},
  address   = {San Francisco},
  issn      = {1932-6203},
  doi       = {10.1371/journal.pone.0203384},
  pages     = {1 -- 12},
  year      = {2018},
  abstract  = {Background: Infection with human immunodeficiency virus (HIV) affects muscle mass, altering independent activities of people living with HIV (PLWH). Resistance training alone (RT) or combined with aerobic exercise (AE) is linked to improved muscle mass and strength maintenance in PLWH. These exercise benefits have been the focus of different meta-analyses, although only a limited number of studies have been identified up to the year 2013/4. An up-to-date systematic review and meta-analysis concerning the effect of RT alone or combined with AE on strength parameters and hormones is of high value, since more and recent studies dealing with these types of exercise in PLWH have been published. Methods: Randomized controlled trials evaluating the effects of RT alone, AE alone or the combination of both (AERT) on PLWH was performed through five web-databases up to December 2017. Risk of bias and study quality was attained using the PEDro scale. Weighted mean difference (WMD) from baseline to post-intervention changes was calculated. The I2 statistics for heterogeneity was calculated. Results: Thirteen studies reported strength outcomes. Eight studies presented a low risk of bias. The overall change in upper body strength was 19.3 Kg (95\% CI: 9.8±28.8, p< 0.001) after AERT and 17.5 Kg (95\% CI: 16±19.1, p< 0.001) for RT. Lower body change was 29.4 Kg (95\% CI: 18.1±40.8, p< 0.001) after RT and 10.2 Kg (95\% CI: 6.7±13.8, p< 0.001) for AERT. Changes were higher after controlling for the risk of bias in upper and lower body strength and for supervised exercise in lower body strength. A significant change towards lower levels of IL-6 was found (-2.4 ng/dl (95\% CI: -2.6, -2.1, p< 0.001). Conclusion: Both resistance training alone and combined with aerobic exercise showed a positive change when studies with low risk of bias and professional supervision were analyzed, improving upper and, more critically, lower body muscle strength. Also, this study found that exercise had a lowering effect on IL-6 levels in PLWH.},
  language  = {en}
}