Physical activity and life satisfaction among adolescents before and during the COVID-19 pandemic.

The negative impact of the COVID-19 pandemic and distance education has significantly affected adolescents' lives. The restrictive policies negatively affected their physical and mental health and life satisfaction. It is therefore desirable to look for ways to eliminate similar negative impacts on adolescents in the future. This study aimed to identify the differences in the association between physical activity and life satisfaction in Polish adolescents before and during the pandemic. The study included 1541 participants (891 before the pandemic and 650 during the pandemic) aged 15-19 years. The International Physical Activity Questionnaire-Long Form questionnaire was used to assess physical activity, and the Bern Subjective Well-Being Questionnaire was used to evaluate life satisfaction. The objectivity of data collection and analysis before and during the pandemic was ensured by the web application the International Database for Research and Educational Support. During the pandemic, we found lower physical activity and life satisfaction in both boys and girls compared to before the pandemic. Girls with low and high physical activity levels showed significantly lower life satisfaction during the pandemic than they did before. Low life satisfaction was associated with lower physical activity, and high life satisfaction was associated with greater total physical activity. Both boys and girls with low and high life satisfaction achieved significantly fewer physical activity recommendations during the pandemic. High life satisfaction increased the likelihood of meeting the recommendations for physical activity before and during the pandemic. This study provides new insights into the differences and associations between life satisfaction and physical activity in adolescent boys and girls before and during the pandemic. It provides suggestions for the prevention of possible future restrictions in the school settings. Support for post-pandemic life satisfaction in adolescents should focus mainly on increasing vigorous physical activity and improving adolescent participation in organized physical activity settings.

Transperitoneal Laparoscopic and Robotic Partial Nephrectomy for Renal Cancer in Patients with Previous Abdominal Surgery: a Single Centre Experience.

Patients with previous abdominal surgery are at an increased risk of peritoneal adhesions, which may complicate transperitoneal surgery. The objective of this article is to report single centre experience with transperitoneal laparoscopic and robotic partial nephrectomy for renal cancer in patients with previous abdominal surgery. We evaluated data from 128 patients who underwent laparoscopic or robotic partial nephrectomy from January 2010 to May 2020. Patients were divided into three groups according to the localization of main previous surgery: in the upper contralateral abdominal quadrant, in the upper ipsilateral abdominal quadrant or in the middle line, in lower abdominal quadrants. Each group was divided into two subgroups (laparoscopic/robotic partial nephrectomy). We separately analysed data of indocyanine green-enhanced robotic partial nephrectomy. Our study did not find significant difference in the rate of intraoperative or postoperative complications between any of the groups. The type of partial nephrectomy (robotic or laparoscopic) affected the surgery time, blood loss, and length of stay in hospital, but did not significantly influence the frequency of complications. Partial nephrectomy in group of patients with prior renal surgery led to a higher rate of intraoperative low-grade complications. We did not observe more favourable results for indocyanine green-enhanced robotic partial nephrectomy. The location of previous abdominal surgery does not influence the rate of intraoperative or postoperative complications. The type of partial nephrectomy (robotic or laparoscopic) does not affect the frequency of complications.

Accelerometry-based assessment of physical activity and sedentary behavior in adult survivors of childhood acute lymphoblastic leukemia and their healthy peers.

Adult survivors of childhood acute lymphoblastic leukemia (ASALL) compose a specific group that faces an increased risk of experiencing late effects of their earlier treatment. Physical activity (PA) may be one of the appropriate means for preventing or minimizing the late effects of treatment. The main purpose of this study is to characterize device-measured PA and sedentary behavior (SB) among ASALL. The specific objective was to compare the movement behavior with a group recruited from the healthy population and to determine the degree of compliance with health recommendations for PA in the adult population. Twenty ASALL and 21 healthy control group (CG) members participated in the study. Participants were between 18 and 30 years old. Movement behavior was assessed for seven days using an Axivity AX3 accelerometer and a 24-h wearing protocol. Movement behavior was characterized by the amount of time spent in SB, light PA (LPA), moderate PA (MPA), and vigorous PA (VPA). There were no significant differences in movement behavior or compliance with PA recommendations between the ASALL and CG. During the week, the ASALL accumulated 711 min per day of SB vs. 636 min per day in the CG (p = 0.26); the ASALL had 186 min per day of LPA vs. 201 min per day in the CG (p = 0.47); the ASALL had 132 min per day of MPA vs. 147 min per day in the CG (p = 0.25); and the ASALL had 5 min per day of VPA vs. 4 min per day in the CG (p = 0.48). All research participants (ASALL and CG) met the PA recommendations of > 150 min per week for moderate PA. The results of our study suggest that ASALL, even after suffering from that disease in childhood, display comparable levels of PA and SB to their healthy peers. Both groups met the health recommendations for PA. The device-based monitoring of PA and SB should be an integral part of monitoring the late effects of treatment.

The Role of Volunteers in a Swimming Organization for Persons with Disabilities.

Participation in leisure time physical activity (LTPA) has considerable health-related, psychological, and social benefits. However, the involvement of individuals with disabilities is considerably less than that of their peers without disabilities. A higher rate of participation of individuals with disabilities in LTPA may be achieved by the active involvement of volunteers. This study aimed to describe the importance of volunteer involvement in a swimming organization focused on individuals with disabilities, as perceived by all participants, including swimmers with disabilities, their parents, volunteers, and coaches. The organization uses volunteers as swimming instructors who work individually with swimmers with disabilities. The data were obtained through 11 semi-structured interviews with swimmers with disabilities and their parents, volunteers, and coaches. The interviews were transcribed verbatim and analyzed using a five-step inductive thematic analysis. As a result of the cooperation with the volunteer swimming instructors, swimmers with disabilities felt an improved range of movement, greater independence, and higher self-esteem than before they started using the services of the swimming organization. Consequently, even individuals with severe disabilities can participate in LTPA. Membership to the organization also provided space for the establishment of new social relations, and the instructors described them accepting persons with disabilities as their equals. More importantly, the involvement of volunteers enables organizations to provide respite care for parents.

Movement behaviours in paediatric cancer survivors during recovery and school weeks.

Purpose: Paediatric cancer survivors (PCS) are a high-risk population, who can suffer from late effects of their treatment, such as metabolic syndrome, cardiovascular conditions, secondary tumours. Optimal movement behaviours (e.g., limited sedentary behaviour [SB] and sufficient physical activity [PA]) can reduce the side effects or avoid late effects of their treatment. The aims of this study were to analyse movement behaviours and meeting the recommendation of 60 minutes of moderate-to-vigorous physical activity (MVPA) a day in Czech PCS, and to compare their movement behaviours during recovery and school weeks in relation to gender, age, and cancer type. Methods: Twenty-six PCS aged 7-15 years in remission stage took part in the cross-sectional study. Movement behaviours were measured with Actigraph wGT3X+ accelerometers worn 24 hour/day for 20 consecutive days covering recovery week (13 days at recovery camp) and school week (7 days). Based on cancer types, the PCS were categorized into haematological malignancy or solid tumours group. Results: In the PCS, movement behaviours differed between recovery and school weeks. During recovery week, the PCS showed less SB (451.8 vs. 552.3 min/day, p < 0.001) and spent more time on light PA (350.3 vs. 255.1 min/day, p < 0.001), moderate PA (73.2 vs. 37.4 min/day, p < 0.001), and vigorous PA (10.3 vs. 4.0 min/day p < 0.001) than during school week. The PA recommendation was met by 77% (n = 20) PCS during recovery week, but only by 15% (n = 4) individuals during school week. Conclusions: The PCS recorded higher levels of PA and lower levels of SB during recovery week than during school week. If provided with appropriate conditions, PCS in the remission stage are able to reach the PA level recommended for the healthy population. Recovery week can be a suitable platform for gaining experience that PCS are able to meet the recommended PA level and could be an integral part of reconditioning and resocialization programmes for PCS after the completion of their treatment.

Actigraphy-Based Characteristics of Sleep in Paediatric Cancer Patients in Remission and a Comparison with Their Healthy Peers in the Recovery Stay.

Background: Previous research has demonstrated that paediatric cancer survivors (PCS) have lower sleep quality than their healthy peers. However, the research to date has focused mainly on self-reported data. Therefore, the aim of this cross-sectional study was to characterise selected sleep parameters in PCS using objective monitoring techniques and to compare them with a control group (CG) of their healthy peers during a structured recovery stay. A specific objective was to characterise sleep with respect to gender, age, and cancer type. Methods: 26 PCS and 38 CG aged 7-15 years participated in the study. Selected sleep indicators (time in bed, total sleep time, sleep efficiency) were objectively assessed with an Actigraph wGT3X-BT accelerometer for 12 days during the recovery stay. Results: No significant differences were found between the PCS and CG groups in terms of the selected sleep parameters. The total time in bed was 543.1 min/day in the PCS and 537.2 min/day in the CG (p=0.91). The total sleep time was 455.3 min/day in the PCS and 457.5 min/day in the CG (p=0.57). Sleep efficiency was 85.3% in the PCS and 86.3% in the CG (p=0.36). Sleep efficiency >85% was achieved by 62% of the PCS (n=16) and 68% of the CG (n=26). There were no significant differences in sleep parameters in terms of variables such as gender, age, or cancer type. Conclusion: The results of our study suggest that - under the same conditions - the PCS did not differ from their healthy peers in terms of the indicators of time in bed, total sleep time, and sleep efficiency. No significant differences according to age, gender, or cancer type were found.

Dislocation avalanches are like earthquakes on the micron scale.

Compression experiments on micron-scale specimens and acoustic emission (AE) measurements on bulk samples revealed that the dislocation motion resembles a stick-slip process - a series of unpredictable local strain bursts with a scale-free size distribution. Here we present a unique experimental set-up, which detects weak AE waves of dislocation slip during the compression of Zn micropillars. Profound correlation is observed between the energies of deformation events and the emitted AE signals that, as we conclude, are induced by the collective dissipative motion of dislocations. The AE data also reveal a two-level structure of plastic events, which otherwise appear as a single stress drop. Hence, our experiments and simulations unravel the missing relationship between the properties of acoustic signals and the corresponding local deformation events. We further show by statistical analyses that despite fundamental differences in deformation mechanism and involved length- and time-scales, dislocation avalanches and earthquakes are essentially alike.

Does Vigorous Physical Activity Contribute to Adolescent Life Satisfaction?

BACKGROUND: Physical and mental health are the basis of life satisfaction (LS), even during adolescence. The aim of this study was to identify the associations between LS and types of physical activity (PA) in Czech and Polish boys and girls. METHODS: The research involved 933 girls and 663 boys aged 15-19 years. LS was diagnosed using the Bern Subjective Well-Being Questionnaire and the WHO-5 Well-Being Index. The International Physical Activity Questionnaire-long form (IPAQ-LF) questionnaire was used to identify the types of weekly PA. RESULTS: Adolescents with the highest LS had more recreational, moderate, vigorous, and total weekly PA. The strongest associations between LS and PA were in the Czech and Polish boys and girls who participated in vigorous PA (VPA). The recommendations for VPA were fulfilled by 45% of Czech and 46% of Polish boys and 40% of Czech and 50% of Polish girls, with the highest LS. The most significant positive moderator between LS and PA was participation in organized PA. Boys with the highest LS were 1.94 times more likely to meet the weekly recommendation of VPA than boys with the lowest LS. Similarly, girls with the highest LS were 1.77 times more likely to meet these recommendations. CONCLUSIONS: Promoting both current subjective well-being and organized PA, with an emphasis on achieving the VPA recommendations, may support general LS and a healthy lifestyle in adolescents.

The Effect of Different Thermal Treatment on the Allotropic fcc↔hcp Transformation and Compression Behavior of Polycrystalline Cobalt.

Pure polycrystalline cobalt is systematically thermally treated in order to assess the effect of the microstructure on the compression behavior. Isothermal annealing of the as-drawn material leads to recrystallization and grain growth dependent on the annealing temperature (600-1100 ∘C). Consequently, the yield strength decreases and the fracture strain increases as a function of rising grain size; the content of the residual fcc phase is ~6-11%. Subsequent thermal cycling around the transition temperature is applied to further modify the microstructure, especially in terms of the fcc phase content. With the increasing number of cycles, the grain size further increases and the fraction of the fcc phase significantly drops. At the same time, the values of both the yield strength and fracture strain somewhat decrease. An atypical decrease in the fracture strain as a function of grain size is explained in terms of decreasing fcc phase content; the stress-induced fcc→hcp transformation can accommodate a significant amount of plastic strain. Besides controlling basic material parameters (e.g., grain size and texture), adjusting the content of the fcc phase can thus provide an effective means of mechanical performance optimization with respect to particular applications.

Physical Activity of Secondary School Adolescents at Risk of Depressive Symptoms.

BACKGROUND: The aim of the study is to analyze the associations between depressive symptoms (DS), well-being and different types of physical activity (PA) in adolescents. METHODS: Overall, 368 girls and 228 boys aged 15-19 years were involved in the research. To explore the composition of weekly PA, we used the IPAQ-Long questionnaire, and a pedometer was used to monitor weekly PA. The prevalence of DS was diagnosed by the Bern Subjective Well-Being Questionnaire and the WHO-5 Well-Being Index. RESULTS: The girls and boys who reported the most DS and the lowest level of well-being had significantly less weekly recreational PA. The girls who reported the fewest DS had a 2.12 times greater odds of meeting the 11,000 steps/day recommendation than did the girls with the most DS, whereas we did not detect statistically significant differences in rates of meeting the recommendation in the boys with distinct levels of DS. CONCLUSIONS: The study confirms the stronger negative associations between DS and PA, especially among girls. The greatest opportunities for behavioral change in adolescents at the highest risk of DS are in the promotion of recreational PA.

Physical Activity in 15-17-Year-Old Adolescents as Compensation for Sedentary Behavior in School.

The traditional concept of education and school settings significantly contribute to the sedentary behavior of adolescents at secondary schools. The aim of this study is to identify the volume and intensity of physical activity (PA) that adolescent boys and girls engage in during recesses, after school, and during the day to compensate for sedentary behavior in lessons. The study was conducted at 29 Czech and 9 Polish schools. The study involved 868 girls and 409 boys aged 15-17 years. An ActiTrainerTM accelerometer was used to monitor PA and heart rate. Participants were divided into four quartile groups. Most sedentary boys and girls had less PA and showed a worse ratio of physical inactivity (PI)/PA than non-sedentary participants during recesses. In the after-school period, there were no significant differences. On school days, most sedentary boys and girls showed lower PA, a worse ratio of PI/PA, fewer steps·hour-1, and lower energy expenditure than their non-sedentary counterparts. Vigorous PA of ≥8 METs was reached by 48% of most sedentary boys (75% non-sedentary) and 47% of most sedentary girls (54% non-sedentary). Most sedentary adolescents do not compensate for their sedentary behavior in lessons with higher PA intensity or volume during recesses, after-school, or in overall daily PA.

Robotic Partial Nephrectomy with Indocyanine Green Fluorescence Navigation.

Partial nephrectomy (PN) is a recommended type of treatment of localised renal tumors. Real-time intraoperative imaging technique, such as fluorescence imaging with indocyanine green (ICG) administration helps to improve intraoperative and postoperative outcomes in patients who underwent PN. Our work presents results of patients who underwent robotic PN with ICG navigation. A total of 37 patients underwent robotic PN with application of ICG between April 2015 and May 2019. A total amount of 5 mg of ICG was applied intravenously, and then robotic PN was performed with fluorescent imaging. ICG was used by the surgeon's decision according to unfavourable anatomical properties of tumor or to high R.E.N.A.L. nephrometry score. An exact border between perfused and nonperfused tissue was detected, and exact tumor's branch of the renal artery was clamped. Robotic PN with ICG-fluorescence imaging navigation was performed in 37 cases with a preoperative average diameter of tumor of 31 mm. The mean surgery time was 133 minutes, and the mean estimated blood loss was 190 mL. Arterial clamping was performed in 35 cases. The mean duration of warm ischemia was 14 minutes. Application of ICG enabled specific tumor-supplying vessel clamping in 25 cases. Two complications of grade II according to the Clavien-Dindo classification occurred intraoperatively, and one complication of grade III was observed. Renal function changes showed favourable results for the cases with superselective clamping. Finally, an administration of ICG eases superselective clamping of tumor-specific branch of renal artery and helps to preserve normal renal function with acceptable oncological results.

Damage Characterization during Compression in a Perlite-Aluminum Syntactic Foam.

Aluminum matrix (Al99.5) syntactic foam containing expanded perlite particles was produced using the pressure infiltration technique. The dominant deformation mechanisms during compression of this foam were determined by sequential k-means analysis of the acoustic emission data. Since the different deformation mechanisms were concurrently active even at small strains, successive unloading and reloading measurement was proposed for cluster identification. The repetitive unloading and reloading allowed us to identify two mechanical parameters, namely the unloading modulus and the loss for unloading-reloading cycles. Based on the correlations among the strain localization within the specimen, the acoustic emission results, the changes in these mechanical parameters, and the transition from quasi-elastic deformation to plasticity were revealed in this material.

Physical activity of 15-17 years old adolescents in different educational settings: a Polish-Czech study.

OBJECTIVES: The aim of this study was to analyze adolescents' physical activity (PA) in two different educational settings, and to estimate the association between meeting PA recommendations and specific characteristics of adolescents' lifestyle. METHODS: The study was carried out in the Moravia region of the Czech Republic and in the Silesia-Opole region of Poland. In total, 1,846 participants completed the long International Physical Activity Questionnaire (IPAQ-long) using the online Indares system. RESULTS: Results showed that the Polish sample was significantly more physically active than the Czech one concerning school PA (p < 0.001; η2 = 0.07). Comparing by gender, significant differences were found in vigorous PA (p < 0.001; η2 = 0.05) and moderate PA (p < 0.001; η2 = 0.08) in both samples. The recommendations for vigorous PA are met by 45.9% of Czech boys and 33.4% of girls; and by 64.5% of Polish boys and 51.3% of girls. Participation in organized PA was the main correlate to achieve the recommendations of vigorous PA in both Czech (p < 0.001; CI = 4.47-9.25) and Polish adolescents (p < 0.001; CI = 1.99-5.37). CONCLUSIONS: The Polish educational model seems to be more effective for enhancing higher levels of PA among youth, as it provides pupils with a wider offer of organized PA. Girls were found to be less active than boys at high PA intensities in both countries, therefore, more effort must be put on involving them in organized PA.

Micron-Scale Deformation: A Coupled In Situ Study of Strain Bursts and Acoustic Emission.

Plastic deformation of micron-scale crystalline materials differs considerably from bulk samples as it is characterized by stochastic strain bursts. To obtain a detailed picture of the intermittent deformation phenomena, numerous micron-sized specimens must be fabricated and tested. An improved focused ion beam fabrication method is proposed to prepare non-tapered micropillars with excellent control over their shape. Moreover, the fabrication time is less compared with other methods. The in situ compression device developed in our laboratory allows high-accuracy sample positioning and force/displacement measurements with high data sampling rates. The collective avalanche-like motion of the dislocations is observed as stress decreases on the stress-strain curves. An acoustic emission (AE) technique was employed for the first time to study the deformation behavior of micropillars. The AE technique provides important additional in situ information about the underlying processes during plastic deformation and is especially sensitive to the collective avalanche-like motion of the dislocations observed as the stress decreases on the deformation curves.

The Effect of Matrix Composition on the Deformation and Failure Mechanisms in Metal Matrix Syntactic Foams during Compression.

The influence of the matrix material on the deformation and failure mechanisms in metal matrix syntactic foams was investigated in this study. Samples with commercially pure Al (Al) and Al-12 wt % Si (AlSi12) eutectic aluminum matrix, reinforced by hollow ceramic spheres, were compressed at room temperature. Concurrently, the acoustic emission response and the strain field development on the surface were monitored in-situ. The results indicate that the plastic deformation of the cell walls is the governing mechanism in the early stage of straining for both types of foams. At large stresses, deformation bands form both in the Al and AlSi12 foam. In Al foam, cell walls collapse in a large volume. In contrast, the AlSi12 foam is more brittle; therefore, the fracture of precipitates and the crushing of the matrix take place within a distinctive deformation band, along with an occurrence of a significant stress drop. The onset stress of ceramic sphere failure was shown to be not influenced by the matrix material. The in-situ methods provided complementary data which further support these results.

Effect of equal channel angular pressing on in vitro degradation of LAE442 magnesium alloy.

Effect of processing by equal channel angular pressing (ECAP) on the degradation behaviour of extruded LAE442 magnesium alloy was investigated in a 0.1M NaCl solution, Kirkland's biocorrosion medium (KBM) and Minimum Essential Medium (MEM), both with and without 10% of foetal bovine serum (FBS). Uniform degradation of as extruded and ECAP processed samples in NaCl solution was observed, nevertheless higher corrosion resistance was found in the latter material. The increase of corrosion resistance due to ECAP was observed also after 14-days immersion in all media used. Higher compactness of the corrosion layer formed on the samples after ECAP was responsible for the observed decrease of corrosion resistance, which was proven by scanning electron microscope investigation. Lower corrosion rate in media with FBS was observed and was explained by additional effect of protein incorporation on the corrosion layer stability. A cytotoxicity test using L929 cells was carried out to investigate possible effect of processing on the cell viability. Sufficient cytocompatibility of the extruded samples was observed with no adverse effects of the subsequent ECAP processing. In conclusion, this in vitro study proved that the degradation behaviour of the LAE442 alloy could be improved by subsequent ECAP processing and this material is a good candidate for future in vivo investigation.

The effect of brisk walking on postural stability, bone mineral density, body weight and composition in women over 50 years with a sedentary occupation: a randomized controlled trial.

BACKGROUND: To assess the effect of brisk walking on postural stability, bone mineral density (BMD) and body composition in women over 50 years of age with a sedentary occupation. METHODS: A 10-week walking intervention based on self-regulated brisk walking (BW) to or from work of 30-35 min at least 5 times per week. The research included a total of 104 women (58 women in intervention group). The mean center of pressure (COP) velocity in medial-lateral and anterior-posterior directions, mean total COP velocity with eyes open and closed, BMD of the distal forearm and the calcaneus, body weight, fat mass, and lean body mass were assessed. RESULTS: The BW intervention was completed by 76 % of participants. A significant effect (time × group interaction) was confirmed only in the mean COP velocity in the anterior-posterior direction with eyes closed (F = 7.41, P = 0.008). The effect of BW was not confirmed in BMD, body weight, or body composition. The results indicate that the effect of the intervention is influenced by baseline body mass index in body weight, fat mass and visceral adipose tissue. CONCLUSIONS: BW prevents the deterioration of postural stability with eyes closed, which can have a direct effect on reducing the risk of falls under worse spatial orientation and visibility. The presented intervention model is insufficient for weight loss, changes in BMD, or body composition, and its effect should be assessed during a longer period of time. TRIAL REGISTRATION: German Clinical Trials Register DRKS00007638 , registered March 10, 2015 (retrospectively registered).

Differences in the intensity of physical activity during school days and weekends in Polish and Czech boys and girls.

INTRODUCTION AND OBJECTIVE: The physical, mental and social development that occurs in young people through physical activity (PA) is primarily through extracurricular activities. Family, peers and social environment, in addition to schools, interest groups and school sports, play a unique role during this developmental period. The objective of the study was to examine the differences in the intensity of PA during school days and weekends and the relationship between PA and physical inactivity (PI) during these days in Polish and Czech boys and girls. MATERIALS AND METHODS: In total, there were 816 participants among whom 333 met the requirements of 8 hours of continuous recording of PA (ActiTrainer accelerometers) during at least one school and one weekend day. RESULTS: Boys and girls from both countries engaged in virtually the same amount of PA during school and weekend days, and participated in more PA at lower intensities on the weekends compared with school days. CONCLUSIONS: This study surveyed important issues related to global public health, specifically for the school environment and school settings. The important and crucial relations with family were emphasized, which should increase the awareness and understanding of public health problems of this particular research sample. The results indicated that less time was spent in PI, but also that the largest amount of time during the weekends was spent in front of a screen.

The Role of Physical Education Lessons and Recesses in School Lifestyle of Adolescents.

BACKGROUND: This study investigates school lifestyle among adolescents in terms of physical activity (PA) structure: (1) adolescents participating in a physical education lesson (PEL) versus (2) aggregate recess time exceeding 60 minutes. METHODS: The research was conducted in 24 secondary schools in the Czech Republic (boys N = 208, girls N = 433). For the whole day (1-3 days) participants wore the ActiTrainer accelerometer, which monitored PA, and heart rate. A total of 1122 school days were recorded. RESULTS: Both boys and girls participating in a PEL reported significantly better results compared with nonparticipating individuals regarding all indicators of volume and intensity of school PA (SPA). In most SPA indicators, longer aggregate recess time (>60 minutes) had a statistically significant effect, particularly on the volume of SPA. The recommended 500 steps/hours for SPA was achieved by 83% of boys participating in PEL and 69% of girls. In contrast just 32% of nonparticipating boys and 31% of girls reached this level. With longer recess time the recommendation was met by 43% of boys (42% of girls) compared with 26% of boys (23% of girls) with shorter recess time. CONCLUSIONS: An increase in SPA and an improved lifestyle in adolescents on school days are significantly supported more by PELs than by longer recess time.