Both the countermovement jump (CMJ) and the isometric mid-thigh pull(IMTP) are frequently used performance tests to monitor neuromuscular fatigueand recovery after exhaustive physical activities. However, to date, neitherthe reliability nor the validity of the CMJ and IMTP performed after thecardiopulmonary exercise testing (CPET) has been studied. Thus, this studyprimarily aimed to investigate the intrasession relative and absolute reliability ofthe CMJ and IMTP when performed after the CPET. Second, the study aimedto examine the discriminative validity of the CMJ and IMTP performed after theCPET by differentiating between elite male and female athletes. Twenty-eightfemale (26.8 ± 6.6 years) and seventeen male (23.8 ± 3.5 years) elite Swedishathletes voluntarily participated in the study. Protocols included anthropometricmeasurements, a cycle ergometer-based CPET (i.e., VO_2peak test), followed bythree maximal test-retest CMJ and IMTP trials. Jump height, peak power, andrelative peak power during CMJ and peak force and relative peak force duringIMTP testing were analysed. Results showed high relative reliability of the CMJand IMTP in the total sample (ICC: 0.97 and 0.98) and separately in male (ICC:0.88 and 0.98) and female (ICC: 0.98 and 0.93) athletes. The good absolutereliability of the CMJ and IMTP was evidenced by low within-subjects testretestvariability (CVWS%) and typical measurement error percentage, rangingbetween 5.7% and 6.5% and 6.3% and 8.9%, respectively. Both the CMJ and IMTPshowed good test sensitivity, with the smallest worthwhile change exceedingthe typical error. The CMJ’s jump height, relative peak power, and IMTP’s peakforce showed a large discriminatory capacity to differentiate between maleand female athletes (Cohen’s d = 3.92, 1.80 and 5.14, respectively). However,when the peak force was standardised relative to body mass and lean mass,the differences between sexes diminished. In conclusion, given that the CMJand IMTP tests demonstrated high reliability and sensitivity following CPET, they could be confidently used as practical tools for monitoring neuromuscular fatigue and recovery, even after exhaustive cardiopulmonary exertion activities. Additionally, the demonstrated discriminative validity in differentiating betweenmale and female athletes further supports their role in sex-specific performanceprofiling.

Aim: We aimed to investigate symptoms of low energy availability (LEA) among athletes and recreational active people, and the associations with EDs, excessive exercise, and motivation for training and dietary behavioural changes. 

Methods: Swedish female national team athletes (n=150) from 26 sports, and recreational active women (n=108), 18-39 years were recruited via sport organizations and social media. Participants filled out an anonymous on-line survey comprising the LEA in Females Questionnaire (LEAF-Q), the Eating Disorder Examination Questionnaire (EDE-Q), the Major Depression Index (MDI), the Exercise Addiction Inventory (EAI), and  the Motivation to Change Questionnaire (MCQ). LEAF-Q total score >8 and EDE-Q Global score >2.3  were used to classify participants as having symptoms of LEA and eating disorders (EDs), respectively.

Results: Of all participants, 47% had symptoms of LEA with no difference between elite athletes (47%) and controls (48%). Participants with LEA had lower body mass and BMI compared to those with no symptoms, while no differences were found in age or training load. Most of the participants with LEA (69%) did not have symptoms of EDs. However, when excluding all participants with ED symptoms (n=65), participants with LEA had higher EDE-Q sub scale scores, MDI and EAI scores, and they reported poorer health status and reduced ability to increase energy intake and to lower the training load compared to participants with no LEA symptoms. 

Conclusion: Our findings confirm earlier indications that symptoms of LEA is frequent among elite athletes as well as sedentary people, and that most LEA cases do not have EDs. However, our findings suggest that symptoms of LEA may still be associated with poor well-being, restricted eating and excessive training behaviour and negative focus on body shape and weight. Reversing LEA by increased energy intake and/or reduced training load is the only treatment to prevent REDs health and performance implications. Our findings therefore emphasize the need for multidisciplinary prevention strategies to ensure necessary dietary and training behavioural changes.

Purpose: Markers for the relationships between structural and microvasculature measures given by optical coherence tomography angiography are necessary to increase the diagnostic and prognostic value of this technique. The aim of this study was to investigate relationships between structural and microvasculature measures around the fovea in healthy eyes of healthy children.

Methods: Observational cross-sectional study involving children aged 8–17 years, born at full-term, with no eye disease. The better of two 3 × 3 mm macular scans obtained with a Cirrus 5000HD-OCT was analysed. Images were corrected for lateral magnification errors. Vessel density and perfusion were measured with ImageJ/Fiji software for the superficial capillary plexus. Structural measures including foveal and macular thicknesses were performed manually.

Results: The sample included 86 participants, 51 (59%) females. Mean age was 12.4 years (SD = 2.5); mean best-corrected acuity was −0.10 logMAR (SD = 0.09); mean refractive error was +0.59 D (SD = 1.3) and mean axial length was 23.1 mm (SD = 0.86). Mean area of the foveal avascular zone (AFAZ) was 0.20 mm2 (SD = 0.88); median fovea-to-macula thickness ratio (FMTR) was 0.63 (IQR = 0.08); mean central vessel density was 12.42 mm−1 (SD = 2.78) and mean central perfusion was 38.66% (SD = 3.83). AFAZ was correlated with central vessel density (p < 0.001), perfusion (p < 0.001), foveal thickness (p < 0.001) and FMTR (p < 0.001). Central vessel density was correlated with foveal thickness (p < 0.001) and FMTR, (p = 0.01). Central perfusion was correlated with foveal thickness (p < 0.001) and FMTR, (p = 0.003).

Conclusion: In this study, foveal thickness, FMTR and foveal microvasculature measurements were correlated. Clinicians need to be aware that shallow foveal pits and persistent foveal microvasculature are likely to occur in optical coherence tomography angiography images. In healthy eyes from healthy children, an atypical high FMTR and a small AFAZ may be associated with incomplete foveal development. The mechanism and functional implications of this remain unknown.

Background Long outdoor stay may cause hazardous exposure to ultraviolet radiation (UVR) from the sun even at high latitudes as in Sweden (Spring to Autumn). On the other hand, long outdoor stay is a strong predictor of primary school children ' s free mobility involving moderate to vigorous physical activity (MVPA). UV-protective outdoor environments enable long outdoor stay. We investigated the concurrent impact of different school outdoor play settings upon pupils ' sun exposure and levels of physical activity across different ages, genders, and seasons. Method During 1 week each in September, March, and May, UVR exposure and MVPA were measured in pupils aged 7-11 years. Erythemally effective UVR exposure was measured by polysulphone film dosimeters and MVPA by accelerometers. Schoolyard play was recorded on maps, and used areas defined as four play settings (fixed play equipment, paved surfaces, sport fields, and green settings), categorized by season and gender. Results During the academic year, sport fields yielded the highest UVR exposures and generated most time in MVPA. In March, time outdoors and minutes in MVPA dropped and UVR exposures were suberythemal at all play settings. In May, green settings and fixed play equipment close to greenery promoted MVPA and protected from solar overexposure during long outdoor stays. Conclusion More outdoor activities in early spring are recommended. In May, greenery attractive for play could protect against overexposure to UVR and stimulate both girls and boys to vigorous play.

Potentials and limitations of sky view fish-eye photography and calculation of the percentage of free sky (sky view factor, SVF) as a proxy to estimate solar ultraviolet radiation (UVR) exposure in shade settings are investigated using controlled situations. SVF and measured solar UVR exposure correlated at high mid-latitude (56.65 degrees N) near autumnal equinox in September. The correlation was enhanced by splitting the sky view images into a south- and a north-half and weighting the south-half higher to account for the direct sun. Sky view images from eight different settings with SVF-values 98.3% - 14.9% were compared to exposure measurements by polysulphone film dosimeter badges in the horizontal zenith-, vertical-south-, east-, west- and north-directions and their combinations. The sky view images were un-split and un-weighted or split and the semi-skies given south/north weights (3.0/1.0) or a higher weight ratio (3.5/0.5). Of all tested combinations split sky view SVFs weighted 3.0/1.0 and compared to horizontal (zenith-oriented) dosimeters yielded the highest correlation (R-2 = 0.96). The weight ratio (3.5/0.5) yielded the 2(nd) highest correlation (R-2 = 0.90) both compared to measured horizontal exposure and compared to the horizontal exposure averaged with the vertical-south-oriented exposure. SVF from sky view fish-eye photography may estimate solar UVR exposure in shade settings.

AIM:

The aim of this study was to measure the percentage of sedentary light and moderate-to-vigorous physical activity (%MVPA) provided by physical education (PE) lessons for Swedish second, fifth and eighth grade students, aged eight, 11 and 14.

METHODS:

We observed 39 PE lessons and divided them into seven lesson categories: ball play, ball games, dance, fitness, playing games, orienteering and gymnastics. Physical activity (PA) during PE was estimated using accelerometers and the height and weight of the children were measured.

RESULTS:

We studied 149 children: 63 in the second grade, 66 in the fifth grade and 19 in the eighth grade. On average, 25% of the PE lessons were spent in MVPA and the mean %MVPA varied with the lesson content, with fitness, orienteering and playing games being the most intense. The highest %MVPA was in the fitness category, providing 33% (8-62%) for girls and 37% (7-72%) for boys. With the exception of the second grade, no significant gender differences in %MVPA were seen.

CONCLUSION:

The content of Swedish PE lessons affected the %MVPA in all age groups. In some content, individuals reached two-thirds of their daily PA recommendations, highlighting the potential that PE contributes to public health goals.

Regulated school days entail less free-living physical activity (PA) and outdoor stay, which may jeopardize the opportunities for cohesive moderate-to-vigorous physical activity (MVPA) and, by extension, children’s health. The role of outdoor stay during school time for pupils’ free-living PA vs. physical education (PE) and indoor stay was studied during one academic year in 196 pupils aged 7–14 years at four schools in mid-southern Sweden during five consecutive days each in September, March, and May. Actigraph GT3X+ Activity monitors were used. Predictors for PA during school stay were expressed as mean daily accelerometer counts and were measured per season, day, grade, gender, weather, and time outdoors. Overall, free-living PA outdoors generated the highest mean accelerometer counts for moderate and vigorous PA. Outdoor PA and PE, representing 23.7% of the total school time contributed to 50.4% of total mean accelerometer counts, and were the greatest contributors to moderate and vigorous PA. Age and weather impacted PA, with less PA in inclement weather and among older pupils. More time outdoors, at all seasons, would favorably increase school children’s chances of reaching recommended levels of PA.

More scheduled outdoor stay is increasingly advocated for school children. This study measured 2(nd), 5(th) and 8(th) graders' erythemal UV-exposure in September, March and May at four Swedish schools. We related those exposures, as fractions of total available ambient radiation, to the schools outdoor environments differing in amount of shade, vegetation, and peripheral city-scape quantified as percentage of free sky view calculated from fish-eye photographs. Exposures correlated with the sky views (with exceptions in May) and were suberythemal. The exposures were also below the threshold limit of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) for hazard evaluation of UVR but were potentially enough for adequate vitamin D formation according to a cited model calculation - as illustrated in the results and discussed. The school environments, typical in southern and middle Sweden, offer enough shade to protect children from overexposure during seasons with potentially harmful solar UV radiation. Pupils' outdoor stay may be extended during September and March. In May extended outdoor stay of the youngest pupils requires a more UVR-protective environment.

¨AimThis study explored physical activity, body mass index (BMI) and overweight and obesity from 2000 to 2013 using a convenience sample of second- and fifth-grade Swedish schoolchildren aged 8-9years and 11-12years, respectively. MethodsWe examined cross-sectional cohorts of 126 second-grade children in 2000, 84 in 2006 and 44 in 2013 and 105 fifth-grade children in 2000 and 38 in 2013. No fifth graders were available in 2006. Physical activity data were collected based on pedometer readings over four consecutive weekdays, and height and weight were measured. Identical instruments and procedures were used in all three years. ResultsThere was an increase in physical activity in second-grade girls from 2000 to 2006 (p<0.01), which then stabilised between 2006 and 2013, but second-grade boys and fifth-grade girls were stable throughout the study period. Fifth-grade boys decreased significantly (24%) from 16670 to 12704 steps per day (p<0.01) from 2000 to 2013. Mean BMI scores remained stable over time. ConclusionTime trends in physical activity differed between boys and girls. Second-grade boys and fifth-grade girls were stable throughout, whereas second-grade girls increased from 2000 to 2006 before stabilising. Fifth-grade boys showed a significant 24% reduction from 2000 to 2013. Changes in recess and leisure time habits, such as smartphone use, may have influenced the result.