A specifying method executed by a processor, the specifying method comprising: specifying a first period for which it is determined that a specific movement or a specific posture is being performed by applying a first threshold relating to a given type of parameter to time series data obtained from a sensor for detecting a movement of a person; specifying a second period (S1310, S1312) for which it is determined that the specific movement or the specific posture is being performed by applying a second threshold to the time series data, the second threshold relating to the same type of parameter as the first threshold or relating to a different type of parameter from that of the first threshold; and specifying a transitional period based on a difference between the second period and the first period, the transitional period corresponding to one of a period of a transition to the specific movement or the specific posture, and another period of another transition from the specific movement or the specific posture to another movement or another posture, wherein: when the first and second thresholds relate to the same type of parameter, the second threshold is set relative to the first threshold such that the second period includes the whole first period and a period which is not included in the first period; and when the first and second thresholds relate to different types of parameter, the second threshold is set relative to the first threshold such that the second period includes at least a portion of the first period and a period which is not included in the first period; and wherein the specifying of the second period includes selecting one second period candidate as the second period, from second period candidates for which it is determined that the specific movement or posture is being performed, when second threshold candidates are changed based on the parameter for the second threshold and the changed second threshold candidates are applied to the time series data, the selection of the one second period candidate as the second period being based on a specific rule, the specific rule including whether or not characteristics of the time series data in the second period candidate satisfy a given specific constraint condition based on features during gait initiation, the specific constraint condition including that a changing quantity of an angle between the leg and the orthogonal to the ground at a first step during the second period candidate is smaller than a changing quantity of said angle at a second step during the same second period candidate. specifying a first period for which it is determined that a specific movement or a specific posture is being performed by applying a first threshold relating to a given type of parameter to time series data obtained from a sensor for detecting a movement of a person; specifying a second period (S1310, S1312) for which it is determined that the specific movement or the specific posture is being performed by applying a second threshold to the time series data, the second threshold relating to the same type of parameter as the first threshold or relating to a different type of parameter from that of the first threshold; and specifying a transitional period based on a difference between the second period and the first period, the transitional period corresponding to one of a period of a transition to the specific movement or the specific posture, and another period of another transition from the specific movement or the specific posture to another movement or another posture, when the first and second thresholds relate to the same type of parameter, the second threshold is set relative to the first threshold such that the second period includes the whole first period and a period which is not included in the first period; and when the first and second thresholds relate to different types of parameter, the second threshold is set relative to the first threshold such that the second period includes at least a portion of the first period and a period which is not included in the first period; and wherein the specifying of the second period includes selecting one second period candidate as the second period, from second period candidates for which it is determined that the specific movement or posture is being performed, when second threshold candidates are changed based on the parameter for the second threshold and the changed second threshold candidates are applied to the time series data, the selection of the one second period candidate as the second period being based on a specific rule, the specific rule including whether or not characteristics of the time series data in the second period candidate satisfy a given specific constraint condition based on features during gait initiation, the specific constraint condition including that a changing quantity of an angle between the leg and the orthogonal to the ground at a first step during the second period candidate is smaller than a changing quantity of said angle at a second step during the same second period candidate.