2006). Assessment of sports participation Data on sports participation were assessed using a questionnaire at baseline. The workers were asked for physically demanding sports during the preceding 12 months. Those who never participated in sports in that year were distinguished

from those who did participate in sports. Furthermore, a distinction in frequency was made, i.e. participation for 3 h per week or more and participation less than 3 h per week. Data analyses We analyzed the course of static Selleck PF-4708671 muscle endurance by age both cross-sectionally and longitudinally during the follow-up period of 3 years. To take account of potentially https://www.selleckchem.com/products/z-vad-fmk.html mathematically parabolic relations with age, we analyzed the cross-sectional data using quadratic regression analyses. We added a squared age term as an independent variable to the regression functions. To correct for the dependency of age and squared age, we used the square of age minus mean age (Cohen 2003). Longitudinally, we analyzed the mean differences in static muscle endurance time at baseline and after 3 years of follow-up for 5-year age groups. MCC950 in vitro This was presented as lines from the middle of the 5-year age groups at baseline to the middle of the 5-year age groups 3 years later. The number of workers for the longitudinal analyses was smaller than the number of workers for the cross-sectional analyses, due to loss to

follow-up. Furthermore, cross-sectionally, we presented stratified results for frequency of sports participation (i.e. never, <0 and <3, and ≥3 h). Finally, for isokinetic lifting strength, VAV2 we analyzed stratified regression functions for sports participation and gender. To analyze to what extent muscular capacity was statistically significantly different for gender- and sport-groups, we added interaction terms to the regression functions. We presented R 2 and regression functions (a, b1 and b2) in addition to the graphics of the regression functions. Results Almost 70% of the workers were male. At baseline, the mean age was 35 years (37 years among men, and 33 years among women); the youngest worker had an age of 19 and the oldest an age of 59. Figure 1 shows the age distribution

of the study population (n = 1,578). Fig. 1 Age distribution of the SMASH working population (n = 1,578) Figure 2 presents the course of static muscle endurance time according to age. This figure presents both the cross-sectional relations at baseline (continuous lines), and the mean differences between baseline and follow-up for different age groups (longitudinal analyses represented by the lines between upper dots at baseline and lower dots after 3 years of follow-up at the middle of the age groups). Cross-sectionally, the mean performance for static endurance time of the back muscles had its optimum at the age of 36 years, with 85% of that optimum at the age of 59 years. For the neck and shoulder muscles, static muscle endurance time at the age of 59 years was 2.0 and 1.