In contrast, from the longitudinal analyses, TGF-beta inhibitor it can be seen that static muscle endurance time of the back, neck and shoulder muscles decreased statistically significantly (P ≤ 0.05) among all age groups with values of 77% on average after three years of follow-up compared with the baseline values. The R 2 is 0.05 or lower, which means that 5%

or less of the variation in static endurance time can be explained by age. Fig. 2 Cross-sectional regression functions of baseline static muscle endurance time of the back muscles a the neck muscles and b the shoulder muscles c by age. Longitudinal means by age groups at baseline [upper dots at the middle of the age groups (19–24 to 54–59 years)] and after 3 years of follow-up [lower dots at the middle of the age groups (22–27 to 57–62 years)] Figure 3 shows baseline static muscle endurance time by age stratified for AZD6094 sports participation. It can be seen that there were only small differences between the sports participation groups. Younger workers who participated in sports for at least 3 h per week had the longest endurance time. There are only small differences between workers who participate in sports for fewer hours per week

or not at all. For older workers, either frequently sporting workers (for the back muscles) or moderate frequently sporting workers (for the shoulder muscles) had the longest endurance time or the endurance time is equal for sporting or not sporting workers (for the neck muscles). Ten percent or less of the variation in static endurance time can be explained by age (R 2 between 0.001 and 0.10). Fig. 3 Cross-sectional JNK-IN-8 clinical trial BCKDHA regression functions of baseline static muscle endurance time of the back muscles (a), the neck muscles (b) and the shoulder muscles (c) by age. Stratified for sports participation: never (continuous lines), >0 and <3 h per week (large dotted lined), and ≥3 h per week (small dotted

lines) Figure 4 presents baseline isokinetic lifting strength by age among men and women stratified for three groups with regard to sports participation. Isokinetic lifting strength of the back and neck/shoulder muscles among the men was, respectively, 1.6 and 2.0 times higher than the isokinetic lifting strength among the women. The figure shows the highest isokinetic lifting strength among young workers who participated in sports 3 h per week or more, and among older workers who participated in sports less than 3 h per week. The differences between men and women were statistically significant (P interaction terms <0.05), but the differences between the three groups on sports participation were not statistically significant (P interaction terms >0.10). Of the variation in isokinetic lifting strength, 12% or less can be explained by age. Fig. 4 Cross-sectional regression functions of isokinetic lifting strength by age a of the back muscles and b the neck/shoulder muscles.