@misc{Dech2019, type = {Master Thesis}, author = {Dech, Silas}, title = {Therapeutisches Klettern nach dem Potsdamer Modell bei Jugendlichen mit Skoliose}, doi = {10.25932/publishup-53207}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-532072}, school = {Universit{\"a}t Potsdam}, pages = {VII, 74, VIII, A1-38}, year = {2019}, abstract = {Bisher ist die Ursache f{\"u}r die Entstehung der meisten Skoliosen noch ungekl{\"a}rt und damit eine kausale Behandlung der Betroffenen unm{\"o}glich. Die vorliegende Arbeit geht davon aus, dass der Ausl{\"o}ser f{\"u}r die sogenannte idiopathische Skoliose eine funktionelle St{\"o}rung von Muskeln ist, die sich in einer verminderten relativen Haltekraft {\"a}ußert. Durch gezielte willk{\"u}rliche Muskelanspannungen k{\"o}nnte es m{\"o}glich sein, kompensatorisch auf die Deformit{\"a}t einzuwirken, um damit ein Fortschreiten zu verhindern bzw. sogar eine Regression hervorzurufen. Insbesondere Patientengruppen mit einem hohen Progressionsrisiko, wie Jugendliche im Wachstumsalter, k{\"o}nnten davon profitieren. Ein Muskeltraining kann mit unterschiedlichsten Hilfsmitteln und Methoden erfolgen. Eine M{\"o}glichkeit bietet auch das Klettern. Im Kern wird daher ein Trainingskonzept zum Therapeutischen Klettern bei Jugendlichen mit Skoliose vorgestellt. Dabei beruft sich der Autor auf das Potsdamer Modell. Dieses Modell erlaubt es, gezielte Kraft{\"u}bungen systematisiert an der Kletterwand in Absprungh{\"o}he umzusetzen. Materielle Sicherungsmaßnahmen sind dadurch nicht erforderlich und eventuell notwendige Korrekturen bzw. Hilfestellungen k{\"o}nnen direkt erfolgen. Hauptinhalt eines Trainings nach dem vorgestellten Konzept sind spielerische Bewegungserfahrung innerhalb der Sportart Klettern und ein Systembouldertraining. In einem beigef{\"u}gten {\"U}bungskatalog werden f{\"u}r letzteres M{\"o}glichkeiten der praktischen Umsetzun-gen gegeben. Die {\"U}bungen fokussieren sich auf die Aktivierung und das Training wirbelk{\"o}rperdero-tierender Muskeln. Im Hauptteil einer Trainingseinheit k{\"o}nnen sie dann in Kombination mit der Kor-rektur der Seitverbiegung und des sagittalen Profils (3D Autokorrektur) unter Aufsicht eines geschul-ten Therapeuten durchgef{\"u}hrt werden. Die Arbeit erhebt den Anspruch, einem Leser vom Fach, die Auswahl der {\"U}bungen und die darin enthaltene individuelle Anpassung an den Patienten aus funktionell-anatomischer Sicht zu begr{\"u}nden. In naher Zukunft wird das Konzept in einer randomisiert kontrollierten Studie untersucht. Alle notwendigen Vorbereitungen wurden im Rahmen dieser Arbeit getroffen.}, language = {de} } @misc{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 = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe 618}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe 618}, number = {618}, issn = {1866-8364}, doi = {10.25932/publishup-46016}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-460166}, 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} } @misc{DechBittmannSchaefer2021, author = {Dech, Silas and Bittmann, Frank and Schaefer, Laura}, title = {Muscle oxygenation level might trigger the regulation of capillary venous blood filling during fatiguing isometric muscle actions}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {11}, issn = {1866-8364}, doi = {10.25932/publishup-52407}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-524078}, pages = {19}, year = {2021}, abstract = {The regulation of oxygen and blood supply during isometric muscle actions is still unclear. Recently, two behavioral types of oxygen saturation (SvO2) and relative hemoglobin amount (rHb) in venous microvessels were described during a fatiguing holding isometric muscle action (HIMA) (type I: nearly parallel behavior of SvO2 and rHb; type II: partly inverse behavior). The study aimed to ascertain an explanation of these two regulative behaviors. Twelve subjects performed one fatiguing HIMA trial with each arm by weight holding at 60\% of the maximal voluntary isometric contraction (MVIC) in a 90° elbow flexion. Six subjects additionally executed one fatiguing PIMA trial by pulling on an immovable resistance with 60\% of the MVIC with each side and same position. Both regulative types mentioned were found during HIMA (I: n = 7, II: n = 17) and PIMA (I: n = 3, II: n = 9). During the fatiguing measurements, rHb decreased initially and started to increase in type II at an average SvO2-level of 58.75 ± 2.14\%. In type I, SvO2 never reached that specific value during loading. This might indicate the existence of a threshold around 59\% which seems to trigger the increase in rHb and could explain the two behavioral types. An approach is discussed to meet the apparent incompatibility of an increased capillary blood filling (rHb) despite high intramuscular pressures which were found by other research groups during isometric muscle actions.}, language = {en} } @misc{BittmannDechAehleetal.2020, author = {Bittmann, Frank and Dech, Silas and Aehle, Markus and Schaefer, Laura}, title = {Manual Muscle Testing—Force Profiles and Their Reproducibility}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {671}, issn = {1866-8364}, doi = {10.25932/publishup-48561}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-485612}, pages = {32}, year = {2020}, abstract = {The manual muscle test (MMT) is a flexible diagnostic tool, which is used in many disciplines, applied in several ways. The main problem is the subjectivity of the test. The MMT in the version of a "break test" depends on the tester's force rise and the patient's ability to resist the applied force. As a first step, the investigation of the reproducibility of the testers' force profile is required for valid application. The study examined the force profiles of n = 29 testers (n = 9 experiences (Exp), n = 8 little experienced (LitExp), n = 12 beginners (Beg)). The testers performed 10 MMTs according to the test of hip flexors, but against a fixed leg to exclude the patient's reaction. A handheld device recorded the temporal course of the applied force. The results show significant differences between Exp and Beg concerning the starting force (padj = 0.029), the ratio of starting to maximum force (padj = 0.005) and the normalized mean Euclidean distances between the 10 trials (padj = 0.015). The slope is significantly higher in Exp vs. LitExp (p = 0.006) and Beg (p = 0.005). The results also indicate that experienced testers show inter-tester differences and partly even a low intra-tester reproducibility. This highlights the necessity of an objective MMT-assessment. Furthermore, an agreement on a standardized force profile is required. A suggestion for this is given.}, language = {en} } @misc{DechBittmannSchaefer2021, author = {Dech, Silas and Bittmann, Frank and Schaefer, Laura}, title = {Assessment of the Adaptive Force of Elbow Extensors in Healthy Subjects Quantified by a Novel Pneumatically Driven Measurement System with Considerations of Its Quality Criteria}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {710}, issn = {1866-8364}, doi = {10.25932/publishup-51095}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-510950}, pages = {25}, year = {2021}, abstract = {Adaptive Force (AF) reflects the capability of the neuromuscular system to adapt adequately to external forces with the intention of maintaining a position or motion. One specific approach to assessing AF is to measure force and limb position during a pneumatically applied increasing external force. Through this method, the highest (AFmax), the maximal isometric (AFisomax) and the maximal eccentric Adaptive Force (AFeccmax) can be determined. The main question of the study was whether the AFisomax is a specific and independent parameter of muscle function compared to other maximal forces. In 13 healthy subjects (9 male and 4 female), the maximal voluntary isometric contraction (pre- and post-MVIC), the three AF parameters and the MVIC with a prior concentric contraction (MVICpri-con) of the elbow extensors were measured 4 times on two days. Arithmetic mean (M) and maximal (Max) torques of all force types were analyzed. Regarding the reliability of the AF parameters between days, the mean changes were 0.31-1.98 Nm (0.61\%-5.47\%, p = 0.175-0.552), the standard errors of measurements (SEM) were 1.29-5.68 Nm (2.53\%-15.70\%) and the ICCs(3,1) = 0.896-0.996. M and Max of AFisomax, AFmax and pre-MVIC correlated highly (r = 0.85-0.98). The M and Max of AFisomax were significantly lower (6.12-14.93 Nm; p ≤ 0.001-0.009) and more variable between trials (coefficient of variation (CVs) ≥ 21.95\%) compared to those of pre-MVIC and AFmax (CVs ≤ 5.4\%). The results suggest the novel measuring procedure is suitable to reliably quantify the AF, whereby the presented measurement errors should be taken into consideration. The AFisomax seems to reflect its own strength capacity and should be detected separately. It is suggested its normalization to the MVIC or AFmax could serve as an indicator of a neuromuscular function.}, language = {en} } @misc{SchaeferDechAehleetal.2021, author = {Schaefer, Laura and Dech, Silas and Aehle, Markus and Bittmann, Frank}, title = {Disgusting odours affect the characteristics of the Adaptive Force in contrast to neutral and pleasant odours}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1866-8364}, doi = {10.25932/publishup-54898}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-548980}, pages = {1 -- 16}, year = {2021}, abstract = {The olfactomotor system is especially investigated by examining the sniffing in reaction to olfactory stimuli. The motor output of respiratory-independent muscles was seldomly considered regarding possible influences of smells. The Adaptive Force (AF) characterizes the capability of the neuromuscular system to adapt to external forces in a holding manner and was suggested to be more vulnerable to possible interfering stimuli due to the underlying complex control processes. The aim of this pilot study was to measure the effects of olfactory inputs on the AF of the hip and elbow flexors, respectively. The AF of 10 subjects was examined manually by experienced testers while smelling at sniffing sticks with neutral, pleasant or disgusting odours. The reaction force and the limb position were recorded by a handheld device. The results show, inter alia, a significantly lower maximal isometric AF and a significantly higher AF at the onset of oscillations by perceiving disgusting odours compared to pleasant or neutral odours (p < 0.001). The adaptive holding capacity seems to reflect the functionality of the neuromuscular control, which can be impaired by disgusting olfactory inputs. An undisturbed functioning neuromuscular system appears to be characterized by a proper length tension control and by an earlier onset of mutual oscillations during an external force increase. This highlights the strong connection of olfaction and motor control also regarding respiratory-independent muscles.}, language = {en} } @phdthesis{Dech2022, author = {Dech, Silas}, title = {Isometric muscle function}, doi = {10.25932/publishup-57126}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-571265}, school = {Universit{\"a}t Potsdam}, pages = {127}, year = {2022}, abstract = {The cumulative dissertation consists of four original articles. These considered isometric muscle ac-tions in healthy humans from a basic physiological view (oxygen and blood supply) as well as possibilities of their distinction. It includes a novel approach to measure a specific form of isometric hold-ing function which has not been considered in motor science so far. This function is characterized by an adaptation to varying external forces with particular importance in daily activities and sports. The first part of the research program analyzed how the biceps brachii muscle is supplied with oxygen and blood by adapting to a moderate constant load until task failure (publication 1). In this regard, regulative mechanisms were investigated in relation to the issue of presumably compressed capillaries due to high intramuscular pressures (publication 2). Furthermore, it was examined if oxygenation and time to task failure (TTF) differs compared to an-other isometric muscle function (publication 3). This function is mainly of diagnostic interest by measuring the maximal voluntary isometric contraction (MVIC) as a gold standard. For that, a person pulls on or pushes against an insurmountable resistance. However, the underlying pulling or pushing form of isometric muscle action (PIMA) differs compared to the holding one (HIMA). HIMAs have mainly been examined by using constant loads. In order to quantify the adaptability to varying external forces, a new approach was necessary and considered in the second part of the research program. A device was constructed based on a previously developed pneumatic measurement system. The device should have been able to measure the Adaptive Force (AF) of elbow ex-tensor muscles. The AF determines the adaptability to increasing external forces under isometric (AFiso) and eccentric (AFecc) conditions. At first, it was questioned if these parameters can be relia-bly assessed by use of the new device (publication 4). Subsequently, the main research question was investigated: Is the maximal AFiso a specific and independent variable of muscle function in comparison to the MVIC? Furthermore, both research parts contained a sub-question of how results can be influenced. Parameters of local oxygen saturation (SvO2) and capillary blood filling (rHb) were non-invasively recorded by a spectrophotometer during maximal and submaximal HIMAs and PIMAs. These were the main findings: Under load, SvO2 and rHb always adjusted into a steady state after an initial decrease. Nevertheless, their behavior could roughly be categorized into two types. In type I, both parameters behaved nearly parallel to each other. In contrast, their progression over time was partly inverse in type II. The inverse behavior probably depends on the level of deoxygenation since rHb increased reliably at a suggested threshold of about 59\% SvO2. This triggered mechanism and the found homeostatic steady states seem to be in conflict with the concept of mechanically compressed capillaries and consequently with a restricted blood flow. Anatomical configuration of blood vessels might provide one hypothetical explanation of how blood flow might be maintained. HIMA and PIMA did not differ regarding oxygenation and allocation to the described types. The TTF tended to be longer during PIMA. As a sub-question, oxygenation and TTF were compared between (HIMA) and intermittent voluntary muscle twitches during a weight holding task. TTF but not oxygenation differed significantly (Twitch > HIMA). A changed neuromuscular control might serve as a speculative explanation of how the results can be explained. This is supported by the finding that the TTF did not correlate significantly with the extent of deoxygenation irrespective of the performed task (HIMA, PIMA or Twitch). Other neuromuscular aspects of muscle function were considered in second part of the re-search program. The new device mentioned above detected different force capacities within four trials at two days each. Among AF measurements, the functional counterpart of a concentric muscle action merging into an isometric one was analyzed in comparison to the MVIC. Based on the results, it can be assumed that a prior concentric muscle action does not influence the MVIC. However, the results were inconsistent and possibly influenced by systematic errors. In con-trast, maximal variables of the AF (AFisomax and AFeccmax) could be measured in a reliable way which is indicated by a high test-retest reliability. Despite substantial correlations between force variables, the AFisomax differed significantly from MVIC and AFmax, which was identical with AFeccmax in almost all cases. Moreover, AFisomax revealed the highest variability between trials. These results indicate that maximal force capacities should be assessed separately. The adaptive holding capacity of a muscle can be lower compared to a commonly determined MVIC. This is of relevance since muscles frequently need to respond adequately to external forces. If their response does not correspond to the external impact, the muscle is forced to lengthen. In this scenario, joints are not completely stabilized and an injury may occur. This outlined issue should be addressed in future research in the field of sport and health sciences. At last, the dissertation presents another possibility to quantify the AFisomax by use of a handheld device applied in combination with a manual muscle test. This assessment delivers a more practical way for clinical purposes.}, language = {en} } @misc{SchaeferCarnariusDechetal.2023, author = {Schaefer, Laura and Carnarius, Friederike and Dech, Silas and Bittmann, Frank}, title = {Repeated measurements of Adaptive Force}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {831}, issn = {1866-8364}, doi = {10.25932/publishup-58803}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-588030}, pages = {19}, year = {2023}, abstract = {The Adaptive Force (AF) reflects the neuromuscular capacity to adapt to external loads during holding muscle actions and is similar to motions in real life and sports. The maximal isometric AF (AFisomax) was considered to be the most relevant parameter and was assumed to have major importance regarding injury mechanisms and the development of musculoskeletal pain. The aim of this study was to investigate the behavior of different torque parameters over the course of 30 repeated maximal AF trials. In addition, maximal holding vs. maximal pushing isometric muscle actions were compared. A side consideration was the behavior of torques in the course of repeated AF actions when comparing strength and endurance athletes. The elbow flexors of n = 12 males (six strength/six endurance athletes, non-professionals) were measured 30 times (120 s rest) using a pneumatic device. Maximal voluntary isometric contraction (MVIC) was measured pre and post. MVIC, AFisomax, and AFmax (maximal torque of one AF measurement) were evaluated regarding different considerations and statistical tests. AFmax and AFisomax declined in the course of 30 trials [slope regression (mean ± standard deviation): AFmax = -0.323 ± 0.263; AFisomax = -0.45 ± 0.45]. The decline from start to end amounted to -12.8\% ± 8.3\% (p < 0.001) for AFmax and -25.41\% ± 26.40\% (p < 0.001) for AFisomax. AF parameters declined more in strength vs. endurance athletes. Thereby, strength athletes showed a rather stable decline for AFmax and a plateau formation for AFisomax after 15 trials. In contrast, endurance athletes reduced their AFmax, especially after the first five trials, and remained on a rather similar level for AFisomax. The maximum of AFisomax of all 30 trials amounted 67.67\% ± 13.60\% of MVIC (p < 0.001, n = 12), supporting the hypothesis of two types of isometric muscle action (holding vs. pushing). The findings provided the first data on the behavior of torque parameters after repeated isometric-eccentric actions and revealed further insights into neuromuscular control strategies. Additionally, they highlight the importance of investigating AF parameters in athletes based on the different behaviors compared to MVIC. This is assumed to be especially relevant regarding injury mechanisms.}, language = {en} } @misc{SchaeferDechWolffetal.2022, author = {Schaefer, Laura and Dech, Silas and Wolff, Lara L. and Bittmann, Frank}, title = {Emotional Imagery Influences the Adaptive Force in Young Women}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {816}, issn = {1866-8364}, doi = {10.25932/publishup-58201}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-582014}, pages = {23}, year = {2022}, abstract = {The link between emotions and motor function has been known for decades but is still not clarified. The Adaptive Force (AF) describes the neuromuscular capability to adapt to increasing forces and was suggested to be especially vulnerable to interfering inputs. This study investigated the influence of pleasant an unpleasant food imagery on the manually assessed AF of elbow and hip flexors objectified by a handheld device in 12 healthy women. The maximal isometric AF was significantly reduced during unpleasant vs. pleasant imagery and baseline (p < 0.001, dz = 0.98-1.61). During unpleasant imagery, muscle lengthening started at 59.00 ± 22.50\% of maximal AF, in contrast to baseline and pleasant imagery, during which the isometric position could be maintained mostly during the entire force increase up to ~97.90 ± 5.00\% of maximal AF. Healthy participants showed an immediately impaired holding function triggered by unpleasant imagery, presumably related to negative emotions. Hence, AF seems to be suitable to test instantaneously the effect of emotions on motor function. Since musculoskeletal complaints can result from muscular instability, the findings provide insights into the understanding of the causal chain of linked musculoskeletal pain and mental stress. A case example (current stress vs. positive imagery) suggests that the approach presented in this study might have future implications for psychomotor diagnostics and therapeutics.}, language = {en} } @misc{DechBittmannSchaefer2022, author = {Dech, Silas and Bittmann, Frank and Schaefer, Laura}, title = {Muscle oxygenation and time to task failure of submaximal holding and pulling isometric muscle actions and influence of intermittent voluntary muscle twitches}, series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1866-8364}, doi = {10.25932/publishup-56687}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-566878}, pages = {1 -- 10}, year = {2022}, abstract = {Background Isometric muscle actions can be performed either by initiating the action, e.g., pulling on an immovable resistance (PIMA), or by reacting to an external load, e.g., holding a weight (HIMA). In the present study, it was mainly examined if these modalities could be differentiated by oxygenation variables as well as by time to task failure (TTF). Furthermore, it was analyzed if variables are changed by intermittent voluntary muscle twitches during weight holding (Twitch). It was assumed that twitches during a weight holding task change the character of the isometric muscle action from reacting (≙ HIMA) to acting (≙ PIMA). Methods Twelve subjects (two drop outs) randomly performed two tasks (HIMA vs. PIMA or HIMA vs. Twitch, n = 5 each) with the elbow flexors at 60\% of maximal torque maintained until muscle failure with each arm. Local capillary venous oxygen saturation (SvO2) and relative hemoglobin amount (rHb) were measured by light spectrometry. Results Within subjects, no significant differences were found between tasks regarding the behavior of SvO2 and rHb, the slope and extent of deoxygenation (max. SvO2 decrease), SvO2 level at global rHb minimum, and time to SvO2 steady states. The TTF was significantly longer during Twitch and PIMA (incl. Twitch) compared to HIMA (p = 0.043 and 0.047, respectively). There was no substantial correlation between TTF and maximal deoxygenation independently of the task (r = - 0.13). Conclusions HIMA and PIMA seem to have a similar microvascular oxygen and blood supply. The supply might be sufficient, which is expressed by homeostatic steady states of SvO2 in all trials and increases in rHb in most of the trials. Intermittent voluntary muscle twitches might not serve as a further support but extend the TTF. A changed neuromuscular control is discussed as possible explanation.}, language = {en} }