Introduction Prolonged walking, sitting and standing were thought a risk factor of low back pain. We wanted to measure the prolonged walking, sitting and standing time among workers at the workplace to evaluate their low back pain. But it was difficult to measure these times. Foot planter pressure shifts according to the walking, sitting and standing modes. We handmade an insole typed foot planter pressure data logger and algorithm to presume the walking, sitting and standing time from the foot planter pressure data.

Methods The foot planter pressure data logger was composed by two resistive pressure sensors, a microcontroller, a micro SD card memory and a lithium ion battery. The foot planter pressure data downloaded to a personal computer and analysed to presume walking, sitting and standing time using visual basic software. We validated the presumption time of walking, sitting and standing from 10 min real activity time of running, walking, static sitting, dynamic sitting, static standing, dynamic standing, and taking off the shoe, respectively. This protocol did three times by one parson.

Results Concordance rate between the presumption time and the real activity time was running 83%±12%, walking 100%±0%, static sitting 96%±6%, dynamic sitting 100%±0%, static standing 93%±6%, dynamic standing 73%±38%, and taking off the shoe 97%±6%, respectively. To join the running and walking time to the walking time, the static and dynamic sitting time to the sitting time, the static and dynamic standing time to the standing time, the concordance rate was up to 98.5%±3%, 100.2%±3%, and 100.2%±7%, respectively.

Conclusion The insole typed foot planter pressure data logger had almost 98% concordance rate between the presumption time and the real activity time of walking, sitting and standing. We could measure the walking, sitting and standing time of workers during their working time.