A computer-based method for identifying risk during lifting activities comprising: receiving a first signal from a wearable device generated from dynamic activity of the wearable device over time; identifying, from the first signal, an initiation time for a physical activity performed by a wearer of the wearable device; excerpting a first signal segment from the first signal for a time period following the initiation time for the physical activity; calculating measurements of the wearer for the time period during the physical activity from the first signal segment; and calculating a risk metric from a risk model based on the measurements of the wearer for the time period during the physical activity, the risk metric being indicative of high risk lifting activity; wherein data from the initiation time of the physical activity is taken and is processed immediately upon detecting the initiation time of the physical activity, the method further comprising steps for calibrating the wearable device comprising: providing the user with the wearable device, wherein the wearable device comprises a clip having a switch activated by the closure of the clip; monitoring the clip of the wearable device and confirming a closure of the clip, and when the closure of the clip is confirmed conducting the steps: determining that an actual physical posture of a user wearing the wearable device corresponds to a known physical posture; receiving, at a processor, the first signal from the wearable device generated from dynamic activity of the wearable device over time; initiating a calibration sequence, the calibration sequence including excerpting a calibration window of the first signal and recording, at a memory, offsets in the first signal relative to physical characteristics corresponding to the known physical posture; incorporating the offsets into an adjusted first signal; identifying, in a portion of the adjusted first signal following the calibration window, a signal segment corresponding to a physical activity; and identifying the physical activity based on the signal segment. receiving a first signal from a wearable device generated from dynamic activity of the wearable device over time; identifying, from the first signal, an initiation time for a physical activity performed by a wearer of the wearable device; excerpting a first signal segment from the first signal for a time period following the initiation time for the physical activity; calculating measurements of the wearer for the time period during the physical activity from the first signal segment; and calculating a risk metric from a risk model based on the measurements of the wearer for the time period during the physical activity, the risk metric being indicative of high risk lifting activity; wherein data from the initiation time of the physical activity is taken and is processed immediately upon detecting the initiation time of the physical activity, the method further comprising steps for calibrating the wearable device comprising: providing the user with the wearable device, wherein the wearable device comprises a clip having a switch activated by the closure of the clip; monitoring the clip of the wearable device and confirming a closure of the clip, and when the closure of the clip is confirmed conducting the steps: determining that an actual physical posture of a user wearing the wearable device corresponds to a known physical posture; receiving, at a processor, the first signal from the wearable device generated from dynamic activity of the wearable device over time; initiating a calibration sequence, the calibration sequence including excerpting a calibration window of the first signal and recording, at a memory, offsets in the first signal relative to physical characteristics corresponding to the known physical posture; incorporating the offsets into an adjusted first signal; identifying, in a portion of the adjusted first signal following the calibration window, a signal segment corresponding to a physical activity; and identifying the physical activity based on the signal segment. determining that an actual physical posture of a user wearing the wearable device corresponds to a known physical posture; receiving, at a processor, the first signal from the wearable device generated from dynamic activity of the wearable device over time; initiating a calibration sequence, the calibration sequence including excerpting a calibration window of the first signal and recording, at a memory, offsets in the first signal relative to physical characteristics corresponding to the known physical posture; incorporating the offsets into an adjusted first signal; identifying, in a portion of the adjusted first signal following the calibration window, a signal segment corresponding to a physical activity; and identifying the physical activity based on the signal segment.