Kari Nissinen

Effects of a workplace physical exercise intervention on the intensity of headache and neck and shoulder symptoms and upper extremity muscular strength of office workers : A cluster randomized controlled cross-over trial

&NA; The purpose of the study was to examine the effects of a workplace physical exercise intervention on the perceived intensity of headache and the intensity of symptoms in the neck and shoulders, as well as on the extension and flexion strength of the upper extremities. The study was a cluster randomized controlled trial. The cross‐over design consisted of physical exercise intervention (15 weeks) and no‐intervention (15 weeks). The subjects (n=53) were office workers (mean age 46.6 (SD 8.4)) who reported headache (n=41) symptoms in the neck (n=37) or shoulders (n=41), which had restricted their daily activities during the last 12 months. Pain symptoms were measured using the Borg CR10 scale and muscular strength with a 5RM test. Statistical analyses were based on linear mixed models. Physical exercise intervention resulted in a slight, but statistically significant, decrease in the intensity of headache and neck symptoms, as well as an increase in the extension strength of the upper extremities. The mean decrease in headache during the 5‐week period was 0.64 CR10 (95% CI 0.28–1.00) (P=0.001) or 49% (95% CI 22–77), and 0.42 CR10 (95% CI 0.11–0.72) (P=0.002) or 49% (95% CI 13–85) in the intensity of neck symptoms. The mean increase in the extension strength of the upper extremities was 1.3 kg (95% CI 0.5–2.1) (P=0.001) or 4% (95% CI 1–6). The intervention had no effect on the intensity of shoulder symptoms or the flexion strength of the upper extremities. Specific exercise may be clinically important to alleviate headache and neck symptoms.

Effects of a physical exercise intervention on subjective physical well‐being, psychosocial functioning and general well‐being among office workers: A cluster randomized‐controlled cross‐over design

The purpose of the study was to examine the effects of a workplace physical exercise intervention on subjective physical well‐being, psychosocial functioning and general well‐being.

The benefits of interpopulation hybridization diminish with increasing divergence of small populations

Interpopulation hybridization can increase the viability of small populations suffering from inbreeding and genetic drift, but it can also result in outbreeding depression. The outcome of hybridization can depend on various factors, including the level of genetic divergence between the populations, and the number of source populations. Furthermore, the effects of hybridization can change between generations following the hybridization. We studied the effects of population divergence (low vs. high level of divergence) and the number of source populations (two vs. four source populations) on the viability of hybrid populations using experimental Drosophila littoralis populations. Population viability was measured for seven generations after hybridization as proportion of populations facing extinction and as per capita offspring production. Hybrid populations established at the low level of population divergence were more viable than the inbred source populations and had higher offspring production than the large control population. The positive effects of hybridization lasted for the seven generations. In contrast, at the high level of divergence, the viability of the hybrid populations was not significantly different from the inbred source populations, and offspring production in the hybrid populations was lower than in the large control population. The number of source populations did not have a significant effect at either low or high level of population divergence. The study shows that the benefits of interpopulation hybridization may decrease with increasing divergence of the populations, even when the populations share identical environmental conditions. We discuss the possible genetic mechanisms explaining the results and address the implications for conservation of populations.

THE EFFECTS OF MATING SYSTEM AND GENETIC VARIABILITY ON SUSCEPTIBILITY TO TREMATODE PARASITES IN A FRESHWATER SNAIL, LYMNAEA STAGNALIS

Abstract The amount and distribution of genetic variability in host populations can have significant effects on the outcome of host‐parasite interactions. We studied the effect of mating system and genetic variability on susceptibility of Lymnaea stagnalis snails to trematode parasites. Mating system of snails from eight populations differing in the amount of genetic variability was manipulated, and self‐ and cross‐fertilized offspring were exposed to naturally occurring trematode parasites in a controlled lake experiment. Susceptibility of snails varied between populations, but mating‐system treatment did not have a significant effect. Heterozygosity of snails was negatively correlated with the probability of trematode infection, however, suggesting that parasitic diseases may pose a serious threat to populations lacking genetic variability.

Predominance of outcrossing in Lymnaea stagnalis despite low apparent fitness costs of self-fertilization

We have quantified the natural mating system in eight populations of the simultaneously hermaphroditic aquatic snail Lymnaea stagnalis, and studied the ecological and genetic forces that may be directing mating system evolution in this species. We investigated whether the natural mating system can be explained by the availability of mates, by the differential survival of self‐ and cross‐fertilized snails in nature, and by the effects of mating system on parental fecundity and early survival. The natural mating system of L. stagnalis was found to be predominantly cross‐fertilizing. Density of snails in the populations had no relationship with the mating system, suggesting that outcrossing rates are not limited by mate availability at the population densities observed. Contrary to expectations for outcrossing species, we detected no evidence for inbreeding depression in survival in nature with inferential population genetic methods. Further, experimental manipulations of mating system in the laboratory revealed that self‐fertilization had no effect on parental fecundity, and only minor effects on offspring survival. Predominance of cross‐fertilization despite low apparent fitness costs of self‐fertilization is at odds with the paradigm that high self‐fertilization depression is necessary for maintenance of cross‐fertilization in self‐compatible hermaphrodites.

The effect of inbreeding rate on fitness, inbreeding depression and heterosis over a range of inbreeding coefficients

Understanding the effects of inbreeding and genetic drift within populations and hybridization between genetically differentiated populations is important for many basic and applied questions in ecology and evolutionary biology. The magnitudes and even the directions of these effects can be influenced by various factors, especially by the current and historical population size (i.e. inbreeding rate). Using Drosophila littoralis as a model species, we studied the effect of inbreeding rate over a range of inbreeding levels on (i) mean fitness of a population (relative to that of an outbred control population), (ii) within‐population inbreeding depression (reduction in fitness of offspring from inbred versus random mating within a population) and (iii) heterosis (increase in fitness of offspring from interpopulation versus within‐population random mating). Inbreeding rate was manipulated by using three population sizes (2, 10 and 40), and fitness was measured as offspring survival and fecundity. Fast inbreeding (smaller effective population size) resulted in greater reduction in population mean fitness than slow inbreeding, when populations were compared over similar inbreeding coefficients. Correspondingly, populations with faster inbreeding expressed more heterosis upon interpopulation hybridization. Inbreeding depression within the populations did not have a clear relationship with either the rate or the level of inbreeding.

Effects of a workplace physical exercise intervention on the intensity of low back symptoms in office workers: A cluster randomized controlled cross-over design

Objectives. The purpose of the study was to examine the effects of a workplace physical exercise intervention on the intensity of low back symptoms. Methods. The study was a cluster randomized controlled trial with department (n = 4) as the unit of randomization. The subjects were office workers [(n = 36), mean age 47.1 (SD 8.4) years] who self-reported low back symptoms, which restricted their daily activities during the last 12 months. Low back symptoms were measured using the Borg CR10 scale. The cross-over design consisted of one intervention period of light resistance training and guidance and no training and no guidance of 15 weeks duration. Statistical analyses were based on linear mixed models. Results. The active component of the intervention, light resistance training, resulted in a slight, but statistically significant, decrease in the intensity of low back symptoms (p = 0.020). At the average training time of 5 minutes per working day (25 min/week) the average decrease during the 15-week period was 0.42 CR10 (95% CI 0.07–0.77) and 19% (95% CI 3–35). Conclusion. A physical exercise intervention, which included daily light resistance training, conducted during the working day affected low back symptoms in a positive direction among symptomatic office workers.

Northern Lights on TIMSS and PIRLS 2011 : Differences and similarities in the Nordic countries

How is reading literacy taught in Nordic classrooms, and how is this influenced by the curricula? How can we improve mathematics teaching in Nordic classrooms? What is the relationship between scho ...

Effects of Workplace Physical Exercise Intervention on the Physical Perceived and Measured Physical Functioning among Office Workers - A Cluster Randomized Controlled Cross-Over Design

Purpose: The main aim of the present study was to investigate the effects of a workplace exercise intervention on physical functioning. Dose of the exercise and other physical activity outside the intervention were controlled for. The other aims were to determine the physical strain of training and determine training force as a percentage of work time (OPA), leisure time (LTPA) and time spent on all activities (AT). Methods: The study was a cluster randomized controlled trial (CRT) with each department as the unit of randomization (n=36, n=19, n=15, n=25). The cross-over design consisted of one 15-week intervention period of resistance training (30% 1RM) and training guidance, and another period of the same length with no training or guidance. The subjects (n=90) were office workers [mean age 45.7 (SD 8.5) years]. Percentage body fat was measured using bioelectrical impedance, spinal flexibility with goniometer and a cervical measurement system, muscular strength with a 5RM test and a hand grip test. Subjective physical condition was assessed by questionnaire and physical activity by questionnaire and diary. The statistical analysis was based on linear mixed models. Results: The active component of the intervention, light resistance training, significantly increased both subjective physical condition (p=0.015) and upper extremity extension strength (p= 0.001). Intervention had no effect on percentage body fat, spinal flexibility, hand grip strength or lower extremity strength. The estimated increase in subjective physical condition during the 15-week period was 4 units (95% CI 1-7) or 6% and in upper extremity extension strength 1.3 kg (95% CI 0.5- 2.1) or 4%. Relative physical strain, measured as percentage of maximal oxygen consumption, was 33.7%. Training force was 1.12 metabolic equivalent hours per week, representing 2.0% OPA, 5.9% of LTPA and 1.2% of AT. Conclusion: Light resistance training during the working day had a positive effect on the office workers` subjective physical condition and strength of upper extremities. Controlling for training dose and other physical activity outside the intervention and confounding factors provides for a better specificity and understanding of the dose-response and effectiveness of exercise intervention on physical functioning among office workers.

Study guidance experiences, study progress, and perceived learning outcomes of Finnish university students

ABSTRACT In recent decades, the massification and diversification of higher education have generated new challenges for the guidance of university students. The present study focuses on students’ experiences of guidance in relation to their study progress and perceptions of their learning outcomes. The data (n = 4916) were collected from 2010–2013 through yearly Internet surveys whose targeted respondents were the students of a Finnish University. According to the results, general study guidance was a very strong predictor of students’ self-assessed development of their academic and generic skills as well as working life orientation. It also decreased the probability of slow progress in studies. Significant differences between disciplines were found: the Faculty of Education outperformed other faculties in regard to students’ satisfaction with the guidance and the students’ evaluations of their own learning outcomes. The main result of the study is that guidance can play a significant role in students’ academic success.