Effects of Different Types of High-Intensity Interval Training (HIIT) on Endurance and Strength Parameters in Children and Adolescents

High-Intensity Interval Training (HIIT) promises high training effects on aerobic fitness in children, adolescents and adults in a relatively short time. It is therefore well-established in professional training settings. HIIT methods could also be suited to Physical Education (P.E.) lessons and contribute to students\u27 health and fitness. Since HIIT sessions need little time and equipment, they can be efficiently implemented in P.E. However, there are few studies which have examined non-running-based HIIT programs in the school sport setting. We therefore conducted an intervention study including 121 students aged 11-15 attending a secondary school in Baden Württemberg, Germany. The effects of three different forms of HIIT training varying in duration and content (4 × 4 HIIT, 12 × 1 HIIT, CIRCUIT) were analyzed. The training was conducted twice a week over 6 weeks (10-12 sessions). Strength and endurance performances were determined in pre- and posttests prior to and after the intervention. Results verified that all three HIIT programs led to significant improvements in aerobic fitness (p < 0.001; part ŋ2 = 0.549) with no significant interaction between time x group. In contrast to the running-based HIIT sessions, CIRCUIT training also led to significant improvements in all of the measured strength parameters. Retrospectively, students were asked to assess their perception of the training intervention. The HIIT sessions were well-suited to students who considered themselves as "athletic". Less athletic students found it difficult to reach the necessary intensity levels. The evaluation showed that endurance training conducted in P.E. lessons needs a variety of different contents in order to sufficiently motivate students. Students perceiving themselves as "unathletic" may need additional support to reach the required intensities of HIIT. Circuit training sessions using whole-body drills can be efficiently implemented in the P.E. setting and contribute to students\u27 health and fitness

Effects of whole-body high-intensity interval training and different running- based high-intensity interval training protocols on aerobic capacity and strength endurance in young physical education students

High Intensity Interval Training (HIIT) sessions effectively improve aerobic fitness in children and adolescents in relatively short time. Circuit Training arrangements using highly intensive whole-body drills may reach similar results and may seem an appropriate training method for Physical Education settings. So far, only few studies compared the effects of running-based HIIT intervals lasting less than one minute and whole-body circuit training with a control group. This intervention study examined the effects of 12 units of running-based HIIT protocols (10x1 min vs. 15x30 sec.) and a Circuit training regimen implemented over 12 weeks within regular P.E. lessons. 108 students from two secondary schools in Baden Württemberg and Niedersachsen took part in the study. Pre and posttests were conducted to determine training effects with regard to VO2max and strength endurance. The results showed significant improvements in aerobic fitness (+ 5-9%) and strength parameters for all training groups (HIIT 1: t(28) = -1,886, p < 0.05; HIIT 2: t(27) = -2,631, p < 0.01; CIRCUIT: t (25) = -2.834, p < 0.01). Ultrashort intervals and circuit training based on whole-body drills were perceived as significantly more motivating by the students than longer intervals lasting 60 seconds (g = 0.21, 95% CI 0.055-0.356, p < 0.001)

Magnetic field morphology of the ice giants linked to their internal structure

The magnetic fields of the ice giants are multipolar and non-axisymmetric. Voyager-II-data and aurorae-observations suggest magnetic power spectra with similar power in the first three spherical harmonic degrees and a peak in the order m=1. Multipolar, non-axisymmetric fields can be modeled with several different approaches including a high density stratification in the dynamo region, strongly turbulent convection, a dynamo generated by fast zonal jets and a geometrical setup with a deep stably stratified fluid layer below the dynamo region. Earlier studies with this geometry found multipolar fields and in a few cases reproduced the peak in the magnetic power spectra at order m=1 (Stanley and Bloxham, 2006). Here we explore the robustness of the multipolarity (similar power for l=1,2,3) and the m=1-peak for a range of parameters and geometrical setups using 3D numerical dynamo models. We compare our results to internal structure models of the ice giants in order to constrain the parameters and geometrical setups that are in accordance with the magnetic field observations

Predictors of chronic pain following total knee replacement in females and males: an exploratory study

Introduction This study explored whether nociceptive (NS ) and autonomic nervous system (ANS) dysregulation and psychological distress (PD) where predictive of pain six months after primary total knee replacement for osteoarthritis. Methods: ANS regulation (heart rate variability), NS regulation (temporal summation and the conditioned pain modulation effect), PR (pain catastrophizing), and self-reported pain, stiffness and function, were e valuated preoperatively in 56 patients. Pain severity (WOMAC-pain subscale) in the operated knee measured 6 months after surgery was used as the primary outcome in an ANCOVA model to identify independent predictors of pain. Results The data of 47 patients (85.5%) could be analyzed. Postoperative pain severity six months after surgery was significantly associated with reduced heart rate variability () and tended to be related to a lower conditioned pain modulation effect, but only in females. Conclusion The findings of present study suggest the dysregulation of the ANS and NS may be predictive of chronic pain six months after primary total knee replacement and may be sex specific

The exceptional magnetic fields of Uranus and Neptune: Possible generation mechanisms

Unlike other planetary magnetic fields in our solar system the fields of the ice giant planets Uranus and Neptune are neither dipole- dominated nor axisymmetric. Several approaches to explain this ob- servation include turbulent convection in the dynamo region, a high density stratification, low and radially varying electrical conductiv- ity and a dynamo generated by the observed fast zonal jets. Planetary structure models as well as earlier dynamo model results suggest the possible existence of a non-convecting fluid layer below the convecting dynamo region. Such a fluid layer would not stabilize the magnetic field like a solid electrically conducting core would. This might help explain the complex field morphology. Here we present 3D numerical dynamo models in a rotating spherical shell assuming an incompressible fluid with constant electrical conductivity. We investigate the influence of a stably stratified fluid layer on magnetic field morphology by varying its thickness. The magnetic power spectra in harmonic order up to m=3 show the highest power in m=1, similar to observations of the ice giants' spectra. The results and applicability are discussed by considering alternative models leading to power spectra with a peak in m=1 as well as recent research on the ice giants' internal structure and a possible dichotomy based on e.g. their luminosity

Numerical dynamo models for magnetic field generation in the ice giants

The magnetic fields of Uranus and Neptune are not dipole-dominated and are generally more complex than the other planetary magnetic fields in our solar system. Several hypotheses have been proposed to explain their nature. Among these, the existence of a deep stably stratified fluid layer below the dynamo region or a dynamo operating in a large Rayleigh number turbulent regime are two prominent approaches. Both yield magnetic power spectra similar to those observed at the ice giants. A stable fluid layer in the deeper interior may also explain Uranus' low luminosity and could be the signature of a super-ionic water phase (Stanley and Bloxham, 2004). Dynamo action in a turbulently convecting ice layer, on the other hand, also explains the surface heat flow pattern and zonal flow structure, which shows a retrograde equatorial jet flanked by prograde jets (Soderlund et al., 2013). Here we present 3D numerical dynamo models based on data from recent ice giant structure models for the internal density stratification, electrical conductivity profile and aspect ratio. We aim to compare the proposed hypotheses to constrain the parameters and geometry leading to magnetic fields that are comparable to those of the ice giants in morphology and strength by particularly evaluating magnetic power spectra. Furthermore we examine the transition from prograde to retrograde equatorial jets in the turbulent models

Dynamo models for magnetic field generation in Uranus and Neptune

The magnetic fields of the ice giants are multipolar and non-axisymmetric. Voyager-II- data and HST aurorae-observations suggest magnetic power spectra with similar power in the first three spherical harmonic degrees and a peak in the order m=1. Multipolar, non- axisymmetric fields can be modeled with several different approaches including a high density stratification in the dynamo region, strongly turbulent convection, a dynamo generated by fast zonal jets and a geometrical setup with a deep stably stratified fluid layer below the dynamo region. Earlier studies with this geometry found multipolar fields and in a few cases reproduced the peak in the magnetic power spectra at order m=1 (Stanley and Bloxham, 2006). Here we explore the robustness of the multipolarity (similar power for l=1,2,3) and the m=1-peak for a range of parameters and geometrical setups using 3D numerical dynamo models. We compare our results to internal structure models of the ice giants in order to constrain the parameters and geometrical setups that are in accordance with the magnetic field observations