Validation of a non-linear index of heart rate variability to determine aerobic and anaerobic thresholds during incremental cycling exercise in women.

Studies highlight the usage of non-linear time series analysis of heart rate variability (HRV) using the short-term scaling exponent alpha1 of Detrended Fluctuation Analysis (DFA-alpha1) during exercise to determine aerobic and anaerobic thresholds. The present study aims to further verify this approach in women. Gas exchange and HRV data were collected from 26 female participants with different activity levels. Oxygen uptake (VO2) and heart rate (HR) at first (VT1) and second ventilatory thresholds (VT2) were compared with DFA-alpha1-based thresholds 0.75 (HRVT1) and 0.50 (HRVT2). Results: VO2 at VT1 and VT2 were 25.2 ml/kg/min (± 2.8) and 31.5 ml/kg/min (± 3.6) compared with 26.5 ml/kg/min (± 4.0) and 31.9 ml/kg/min (± 4.5) for HRVT1 and HRVT2, respectively (ICC3,1 = 0.77, 0.84; r = 0.81, 0.86, p < 0.001). The mean HR at VT1 was 147 bpm (± 15.6) and 167 bpm (± 12.7) for VT2, compared with 152 bpm (± 15.5) and 166 bpm (± 13.2) for HRVT1 and HRVT2, respectively (ICC3,1 = 0.87, 0.90; r = 0.87, 0.90, p < 0.001). Bland-Altman analysis for VT1 vs. HRVT1 showed a mean difference of - 1.3 ml/kg/min (± 2.4; LoA: 3.3, - 6.0 ml/kg/min) for VO2 and of - 4.7 bpm (± 7.8; LoA: 10.6, - 20.0 bpm) for HR. VT2 vs. HRVT2 showed a mean difference of - 0.4 ml/kg/min (± 2.3; LoA: 4.1, - 4.9 ml/kg/min) for VO2 and 0.5 bpm (± 5.7; LoA: 11.8, - 10.8 bpm) for HR. DFA-alpha1-based thresholds showed good agreement with traditionally used thresholds and could be used as an alternative approach for marking organismic transition zones for intensity distribution in women.

Validity of the Polar H10 Sensor for Heart Rate Variability Analysis during Resting State and Incremental Exercise in Recreational Men and Women.

Heart rate variability (HRV) is frequently applied in sport-specific settings. The rising use of freely accessible applications for its recording requires validation processes to ensure accurate data. It is the aim of this study to compare the HRV data obtained by the Polar H10 sensor chest strap device and an electrocardiogram (ECG) with the focus on RR intervals and short-term scaling exponent alpha 1 of Detrended Fluctuation Analysis (DFA a1) as non-linear metric of HRV analysis. A group of 25 participants performed an exhaustive cycling ramp with measurements of HRV with both recording systems. Average time between heartbeats (RR), heart rate (HR) and DFA a1 were recorded before (PRE), during, and after (POST) the exercise test. High correlations were found for the resting conditions (PRE: r = 0.95, rc = 0.95, ICC3,1 = 0.95, POST: r = 0.86, rc = 0.84, ICC3,1 = 0.85) and for the incremental exercise (r > 0.93, rc > 0.93, ICC3,1 > 0.93). While PRE and POST comparisons revealed no differences, significant bias could be found during the exercise test for all variables (p < 0.001). For RR and HR, bias and limits of agreement (LoA) in the Bland−Altman analysis were minimal (RR: bias of 0.7 to 0.4 ms with LoA of 4.3 to −2.8 ms during low intensity and 1.3 to −0.5 ms during high intensity, HR: bias of −0.1 to −0.2 ms with LoA of 0.3 to −0.5 ms during low intensity and 0.4 to −0.7 ms during high intensity). DFA a1 showed wider bias and LoAs (bias of 0.9 to 8.6% with LoA of 11.6 to −9.9% during low intensity and 58.1 to −40.9% during high intensity). Linear HRV measurements derived from the Polar H10 chest strap device show strong agreement and small bias compared with ECG recordings and can be recommended for practitioners. However, with respect to DFA a1, values in the uncorrelated range and during higher exercise intensities tend to elicit higher bias and wider LoA.

Effects of a structured counselling-based intervention to improve physical activity behaviour of adolescents and young adult cancer survivors - the randomized phase II Motivate AYA - MAYA trial.

OBJECTIVE: To explore whether a structured counselling-based intervention increases vigorous physical activity behaviour of adolescent and young adult cancer survivors. DESIGN: Randomized controlled phase II trial. SETTING: University Cancer Center Hamburg, Germany. SUBJECTS: Eighty-nine participants (mean age 24.1 ± 6.3) were randomized to control (n = 44) or intervention group (n = 45). INTERVENTIONS: The intervention group was consulted about physical activity behaviour via interview (week 0), and telephone counselling (weeks 1, 3 and 12). The control group only received general physical activity guidelines for cancer survivors (week 0). MAIN MEASURES: The primary outcome was the rate of participants with ⩾9 metabolic equivalent (MET)-hours per week of vigorous activity post-intervention, measured with the International Physical Activity Questionnaire. Secondary outcomes included assessing physical activity behaviour (e.g. amount and type of physical activity) and quality of life. Assessments were completed in weeks 0 (baseline), 12 (post-intervention) and 52 (follow-up). RESULTS: Sixty-nine participants completed the post-intervention- and 47 the follow-up-assessment. The rate of participants performing vigorous physical activity increased from baseline to post-intervention for both without differing significantly (P = 0.541). Both increased their total metabolic equivalent from baseline to post-intervention (intervention group from 55.2 ± 43.7 to 61.7 ± 29.4, control group from 75.3 ± 81.4 to 88.3 ± 80.2). At follow-up the intervention group (73.7 ± 80.2) was more active than baseline when compared to the control group (78.5 ± 50.0). CONCLUSIONS: A structured counselling-based physical activity intervention did not significantly impact the level of vigorous physical activity behaviour in adolescent and young adult cancer survivors.

[Reference values in isometric strength diagnostics : Measurement of core strength values in patients with back pain]. / Referenzwerte in der isometrischen Kraftdiagnostik : Messung von Rumpfkraftwerten bei Patienten mit Rückenschmerzen.

OBJECTIVE: Isometric strength testing is known as a valid and reliable tool in the context of functional diagnostics and quality control for chronic low back pain rehabilitation, but reference values differ markedly between varied assessment devices, depending on their biomechanical lever arm framework. This study aimed to evaluate sex and age-specific isometric peak force reference values of trunk muscle functions in all dimensions using the Myoline® test device (Diers, Schlangenbad, Germany). MATERIAL AND METHODS: In a retrospective cross-sectional study, data of 678 (541 females, 137 males) age-clustered (18-35, 36-50, 51-65 years) low back pain patients (ICD-10: M54) were analyzed referring to their absolute (N) and body weight related (N/kg) isometric maximum peak forces in all spatial dimensions (flexion, extension, rotation, lateral flexion) and the corresponding ratios (M ± SD, 95% CI), accompanied by sex and age-related effect analyses (two-way ANOVA). RESULTS: Male and younger patients were significantly stronger than females and older patients (p < 0.05), but none of the ratios differed significantly between any sex or age cluster (p > 0.05). The flexion/extension ratio showed a 1:2 relation, and the rotation and lateral flexion ratios demonstrated a 1:1 relation, but all ratios varied markedly (30-50%). CONCLUSIONS: The demonstrated data represented a special norm for sex and age clustered low back pain patients assessed with the recent Myoline® test device. The markedly varying peak forces and their ratios underlined the individual diversity and heterogeneous state of functional capacities within low back pain patients.

[Job-related satisfaction and health perception of dance teachers]. / Berufsbezogene Zufriedenheit und Gesundheitswahrnehmung von Tanzpädagoginnen und -pädagogen.

BACKGROUND: The dance teacher's own body is considered to be the central working instrument within the movement mediation. Up to now there is a lack of knowledge about the subjective perception of one's own occupationally associated health and satisfaction as well as the identification of occupational characteristics that are detrimental to health. MATERIAL AND METHODS: Within the framework of a questionnaire-based cross-sectional survey, a cohort of dance teachers in Germany were investigated about dimensions of their own health and general job satisfaction in connection with their profession as a dance teacher. Likert scales were primarily used for these assessments. Additionally, general anthropometric and sociodemographic characteristics were recorded. Beside examining the overall cohort, gender-specific differences were tested. The statistical analysis included n = 232 dance teachers (male 51/female 181) aged 43.1 ± 11.0 years. RESULTS: The general state of health was rated as satisfactory (26.1%) to very good (14.7%) by 85.3% of those surveyed. Of the dance teachers 59.2% even rated their health as good (35.3%) to very good. There was a high degree of satisfaction with their own professional practice for 80% of the participants. Most of the dance teachers felt that they were able to deal with the physical (75.7%) and psychological demands of their profession (70.3%). In addition to fears about the future (51.5%), the main burdensome professional characteristics on dance teachers' self-perception were organizational aspects of work (lack of time for family and friends in 28.4%) and economic aspects (income insecurity in 61.0% and lack of old age security in 65.7%). CONCLUSION: The profession as a dance teacher is accompanied by a high level of general satisfaction and a positive perception of one's own state of health. A confirmation of these positive results by injury and illness statistics is still pending. In addition, an improvement in work organization and economic aspects would be desirable.

[Reference values for isometric strength tests]. / Orientierungswerte in der isometrischen Kraftdiagnostik.

BACKGROUND: In the environment of orthopaedic rehabilitation, isometric strength testing is part of the monitoring in order to document the success of the therapy. For clinical applications, reference values, or at least orientation benchmarks, are needed for every single device, because of serious concerns for direct inter-device comparisons. According to functional ratios, there is only little literature covering comparability concerns. This study aimed to demonstrate reference values for two strength diagnosis systems for trunk and knee-joint flexion and extension as well as resulting functional ratios along with analyses of reproducibility and vice-versa comparisons. MATERIALS AND METHODS: In a cross-sectional design, reference values (M, SD, Median, IQR, 5 and 95% percentiles) of 98 healthy adults (47 females, age 25.7±8.2 years, BMI 23.3±2.6 kg/m2) were assessed for trunk and knee flexion and extension and the according functional ratios using either the Myoline or the Frei medical system. For a sub-sample of 20 persons (50% females), the mutual explained total variance (r2) and reliability (ICC3.1, SEM, VK%) were analyzed. RESULTS: Both systems were shown to be reliable (ICC3.1 0.76-0.95), while functional ratios demonstrated a lower reliability (ICC3.1 0.62-0.92). For peak forces, the mutual total explained variance (r2) ranged between 19-68%, for functional ratios on an even lower level (5-21%). CONCLUSION: The resulting strength test values, and especially the related functional ratios, obtained with the two strength test devices are not comparable at all, but each device was shown to be a reliable tool. Distributions of body weight adjusted peak forces and functional ratios may serve as device specific benchmark values for strength testing in clinical environments.

[The effect of electromagnetic fields on tendinopathies : Study on the effect analysis of a singular application of high-energy pulsed electromagnetic fields]. / Die Wirkung von elektromagnetischen Feldern auf Tendinopathien : Studie zur Effektanalyse einer singulären Anwendung von hochenergetischen gepulsten elektromagnetischen Feldern.

OBJECTIVE: Tendinopathies are diseases that often entail long-term treatment consisting of analgesics, physiotherapy, orthotics, and sparing. The aim of this study was to investigate the effect of a single application of a high-energy PEMF (pulsed electromagnetic field) on pain perception and blood born inflammation parameters. METHODS: 34 patients were randomly assigned to a verum group (10 min PEMF, 0,78 T) or a placebo group (10 min sham condition). Prior to and up to one week after the patient blinded treatment (t1-t5), local pain state was assessed by means of algometry as pain pressure threshold (PPT). Accordingly, heat-shock protein 70 (HSP70) levels were analysed. Statistical analyses included 2­way ANOVA (2â€¯× 5). The clinical trial was registered (DRKS00031321). RESULTS: After randomization and drop-out (verum n = 17, placebo n = 13) baseline-analyses did not reveal significant between-group differences for PPT (p = 0,096), for HSP70 (p = 0,524), or any other sample characteristics (p > 0,05). Pain reduction during one week of observation showed to be significantly higher (p = 0,045, η2 = 0,013) for the PEMF group (PPT: +83 bis +139%) compared to the placebo group (PPT: +10 bis +36%). There were no HSP70 associated effects. CONCLUSIONS: A single bout of high energy PEMF led to an immediate pain relief in tendinopathy patients lasting at least for one week, but the hypothesized underlying HSP70 associated inflammatory pathway could not be confirmed.

Factors that influence the angular error in active knee angle reproduction tests: A systematic review and meta-analysis.

Purpose: The systematic review and meta-analysis investigated subject-independent test factors that influence the absolute angle error in active knee angle reproduction tests. Methods: Five electronic databases were searched to identify relevant studies published before 20 December 2023. Studies were included that were published in either English or German and that investigated joint proprioception in the healthy knee. Included studies were also required to have participants 18-60 years old and free of lower-limb injury, neurological disorders and diseases affecting joint position sense. Risk of bias was assessed using a Cochrane risk-of-bias tool. Results: Of the 2023 articles identified, 26 studies (1082 participants) were included in the meta-analysis. The meta-analysis showed a significant pooled standard mean difference in the absolute angular error for body orientation, direction of movement and fatigue. Active knee angle reproduction tests were found to have a lower absolute angular error when performed in the sitting position compared to the prone position (SMD = -0.56; 95% CI = -1.00 to -0.12). The absolute angular error was found to be greater in cases of knee flexion compared to knee extension (SMD = 0.71; 95% CI = 0.18-1.24). General and local muscle fatigue were found to result in a higher absolute angular error (SMD = 1.39; 95% CI = 1.04-1.75). Conclusion: Hence, fatigue, body orientation and direction of movement influence the extent of the absolute angular error in active knee angle reproduction tests. Practitioners should be aware that the test conditions and the patient's level of fatigue can affect the results of such tests and that directly comparing results obtained using different test protocols may not be appropriate. The test protocol should be well documented and applied consistently in the clinical setting. Level of Evidence: Level III, systematic review with meta-analysis.

Prevalence of obesity and associated health risks in soldiers of the German Armed Forces.

BACKGROUND: Obesity rates are rising in the armed forces of Western democratic countries, impacting military readiness and health. This highlights the need for preventive health risk assessments and countermeasures. METHODS: Using mandatory health examination data from 2018 to 2022, we analyzed the prevalence of obesity, health risks, and associated specific military risk factors (rank and unit) in 43,214 soldiers of the German Armed Forces. Statistical methods included χ2 contingencies and binary logistic regressions. RESULTS: The prevalence of obesity (BMI ≥ 30) was 18.0%. Male soldiers (OR = 3.776) and those with an officer's rank (OR = 1.244) had an increased chance for obesity. Serving in a combat unit reduced the chance of being obese (OR = .886). Considering BMI and waist circumference, 2.4% of the total sample faced extremely high cardiovascular and metabolic health risks, while 11.0% and 11.6% had very high or high health risks, respectively. CONCLUSIONS: Our data underscore the importance of targeting obesity-related health risk factors in soldiers to ensure their well-being and deployment readiness.

Quantifying thoracolumbar fascia deformation to discriminate acute low back pain patients and healthy individuals using ultrasound.

Reduced shear strain and deformability of the thoracolumbar fascia has been linked to low back pain. A number of ultrasound examination methods have been developed for laboratory rather than clinical practice. The aim of this study was to examine the reliability and discriminative validity (patients vs. healthy individuals) of an ultrasound (US) measurement method for the quantification of thoracolumbar fascia deformation (TLFD). A cross-sectional study with US assessment and rater blinding was conducted in a manual therapy clinic and a university laboratory. 16 acute low back pain (aLBP) patients and 15 healthy individuals performed a standardized trunk extension task. US measurements of TLFD were carried out independently by two raters by imaging the TLF in the starting and ending positions of the movement. Intra-rater and inter-rater reliability were calculated using intraclass correlation coefficients (ICCs) and minimal detectable changes (MDC) were calculated. Receiver operating characteristic (ROC) curve analysis was used to determine the cut-off for TLFD to discriminate the study groups. Kappa statistics were performed to assess rater agreement in discrimination. Intra-rater reliability was excellent (ICC: .92, MDC: 5.54 mm, p < .001) and inter-rater reliability was good (ICC: .78, MDC: 8.70 mm, p < .001). The cut-off for TLFD was 6 mm with a sensitivity of 100% and a specificity of 93.75% and the raters agreed moderately (κ = 0.74, p < .001) when distinguishing patients and controls. The reliability of the US method for assessing TLFD is moderate to excellent, and the ability to discriminate aLBP patients from healthy individuals is moderate. The method could be used to capture an additional parameter in morphological aLBP screenings.