0–18,000.0) 316.3 (1,795.2) Sitting on heels 71.6 76.8 1.4 (0.0–57.9) 4.2 (6.8) 1.5 (0.0–360.0) 16.7 (46.0) 1.8 (0.0–57.9) 4.5 (7.6) 11.0 (0.0–18,000.0) 193.8 (1,607.5) Squatting 67.4 67.2 0.9 (0.0–83.4) 5.0 (11.5) 2.5 (0.0–300.0)

17.3 (37.8) 0.8 (0.0–78.6) 4.5 (10.2) 6.0 (0.0–2,000) 54.4 (204.5) Crawling 73.2 57.6 0.0 (0.0–7.0) 0.2 (0.9) 0.0 (0.0–900.0) 19.2 (90.5) 0.0 (0.0–7.0) 0.3 (1.0) 2.0 (0.0–9,000.0) 121.7 (822.9) Knee postures in total 100.0 95.2 32.7 (0.0–146.8) 39.3 (32.3) 60.0 (0.0–2,200.0) 152.2 (279.4) 33.9 (0.0–146.8) 42.6 (34.5) 105.0 (0.0–39,850) 762.6 (3,977.0) Survey t 1 (n = 125) resulted in a high percentage (95.2 %) of agreement between subjects’ assessment and measurement for the occurrence of any knee posture, as well, showing a range from 57.6 % (crawling) to 87.2 % (unsupported kneeling) for the learn more single knee postures. Quantification of knee loading The proportion of knee-straining postures during the measuring period over all 190 measurements was 34.1 % (SD, 24.7 %) and the coefficient of variability (CV) was calculated to 0.72. The quantitative assessment of knee loading obtained by self-reports and measurement is presented in Table 1 (duration of knee loading). In contrast to the good agreement found in identifying knee postures, comparing the quantification

of knee load assessed by both methods showed considerable find more differences between questionnaires and measurement. In survey t 0, the median duration of the reported knee postures in total was about twice as high as the corresponding measured result (60.0 compared to 32.7 min). Regarding the median duration of the single kinds of knee postures, the duration of knee postures seemed to be overestimated by the participants (e.g. supported kneeling 11.0 compared to 2.9 min, squatting 2.5–0.9 min), while the agreement between the median results of measurements and self-reports for sitting on heels and crawling was good (1.4 compared to 1.5 min and 0.0–0.0 min, respectively). Obviously, the self-reported durations of knee postures varied to a far greater extent than

science the corresponding measured results (e.g. standard deviation knee postures in total 279.4 compared to 32.3 min). Moreover, extreme and implausible overestimations for all examined postures occurred to a high degree: Self-reported mean durations of knee postures exceeded the mean measurement results many times over (e.g. knee postures in total, 152.2 compared to 39.3 min, supported kneeling, 44.9–9.2 min). These findings could be confirmed for survey t 1, where, for example, the median self-reported duration of knee postures in total was about three times as high as the corresponding measured duration (105.0 compared to 33.9 min), while the differences between the self-reported and measured median durations of the single knee postures ranged from nearly no difference (unsupported kneeling, 20.0 compared to 17.2 min) to slight (crawling, 2.0–0.0 min) to serious overestimation (supported kneeling, 25.0–2.6 min).