Girls with GJH and at least one hypermobile knee performed, compared with NGJH, static balance tasks with higher medial knee muscle activity relative to the lateral activity, and larger postural sway when vision was eliminated. The short- and long-term consequences should be studied further.

Abstract Objectives Childcare workers in Denmark have high prevalence of musculoskeletal pain (MSP) and sickness absence, but the existing knowledge of their physical work demands is limited, hampering preventive initiatives. This study aimed to assess the physical work demands with accelerometers and workplace observations of childcare workers handling children age 0–3. Methods Data collection consisted of an electronic survey, anthropometric measurements, accelerometer measurements providing information of physical activity types and postures with Acti4 software from five consecutive workdays, as well as 4-h visual workplace observation per childcare worker from 16 Danish nurseries. Results In total, 199 childcare workers were enrolled in the study. A total of 4181 working hours of accelerometer measurements and 722 h of workplace observations were carried out. Accelerometer measurements showed that they spent about half of the working day (44.8%) in sedentary postures, and the rest standing (22.8%), moving (13.0%), walking (14.6%), running (0.1%), and climbing stairs (0.7%), with 4.1% in knee straining postures (kneeling and squatting) and 4.3% forward trunk inclination >60°. Workplace observations showed that they carried children 1.8% of the working hours. Conclusions Physical work demands of Danish childcare workers are characterized by about half of the workday being sedentary, and the remaining of the workday being quite evenly distributed between standing and dynamic activities, with low exposures to carrying children. Their exposure to forward bending of the trunk and knee straining postures could impose a risk for MSP and sickness absence, and preventive initiatives should be considered.

Occupational kneeling and squatting are well-documented risk factors for knee disorders. A method using 3 wireless accelerometers to detect and discriminate kneeling and squatting during work were developed based on data from a semi-standardized laboratory protocol. The method was tested for validity under free-living working conditions.The developed method showed high sensitivity (88-99%) and specificity (98-99%) for detection of kneeling and squatting during the semi-standardized laboratory conditions. During free-living working conditions, kneeling showed very high sensitivity (94%) and specificity (99%), while squatting results were non-conclusive due to limited duration of squatting during the free-living working conditions. This method shows great promise for long-term technical measurement of kneeling and squatting during normal working conditions using wireless accelerometers. The method opens up possibilities for using technical measurements to provide valid exposure assessments and intervention evaluations of kneeling and squatting, as well as increased feasibility for technical measurements in large cohort studies.

BackgroundGeneralized Joint Hypermobility (GJH) is associated with increased risk of musculoskeletal joint pain. We investigated neuromuscular performance and muscle activation strategy.MethodsGirls with GJH and non-GJH (NGJH) performed isometric knee flexions (90°,110°,130°), and extensions (90°) at 20 % Maximum Voluntary Contraction, and explosive isometric knee flexions while sitting. EMG was recorded from knee flexor and extensor muscles.ResultsEarly rate of torque development was 53 % faster for GJH. Reduced hamstring muscle activation in girls with GJH was found while knee extensor and calf muscle activation did not differ between groups. Flexion-extension and medial-lateral co-activation ratio during flexions were higher for girls with GJH than NGJH girls.ConclusionsGirls with GJH had higher capacity to rapidly generate force than NGJH girls which may reflect motor adaptation to compensate for hypermobility. Higher medial muscle activation indicated higher levels of medial knee joint compression in girls with GJH. Increased flexion-extension co-activation ratios in GJH were explained by decreased agonist drive to the hamstrings.

Aim The aim of this study was to compare the association between count‐ and activity type–based definitions of light‐intensity physical activity (LIPA) and adiposity markers. Methods A total of 516 Danish workers participated in 1‐4 days of hip‐ and thigh‐based accelerometer measurements. Three definitions of average daily time spent in LIPA were derived: LIPA (1) time spent between 100 and 2029 CPM, LIPA (2) time spent moving and slow walking, and LIPA (3) time spent moving, walking slow, and standing. Adiposity markers were body mass index (BMI), body fat percentage, and waist circumference. The cross‐sectional association between the three LIPA definitions and adiposity markers was analyzed and interpreted using compositional regression models followed by reallocation of time between LIPA, moderate‐to‐vigorous physical activity (MVPA), and sedentary behavior (SB), respectively. Results The geometric means of daily time (min/day) spent in LIPA 1, LIPA 2, and LIPA 3 were 326, 102, and 274, respectively. We found the direction and strength of the association between the relative importance of daily time spent in LIPA and the adiposity markers to depend on the LIPA definition. For example, reallocating 30 minutes from MVPA to LIPA 1, LIPA 2 and LIPA 3 were associated with a 2.97 (95% CI: 0.68; 5.27), −0.71 (95% CI: −1.43; 0.02), and −0.45 (95% CI: −1.01; 0.11) difference in BMI, respectively. Conclusion Our findings highlight the need for caution when comparing results from studies using different definitions of LIPA.