Fig. 3From: The efficacy of a multimodal physical activity intervention with supervised exercises, health coaching and an activity monitor on physical activity levels of patients with chronic, nonspecific low back pain (Physical Activity for Back Pain (PAyBACK) trial): study protocol for a randomised controlled trialThe Fitbit Flex. a the original Fitbit Flex. b the Fitbit Flex with heat-shrink tubing covering the indicator lightsBack to article page