97140: The health care provider performs manual therapy techniques, including soft tissue and joint mobilization, manipulation, manual traction, and/or manual lymphatic drainage to one or more areas. This code requires direct contact of the health care provider with the patient and can be billed in 15-minute units
97530: Dynamic therapeutic activities designed to achieve improved functional performance (e.g., lifting, pulling, bending) are used. This code requires direct, one-on-one contact with the patient and can be billed in 15-minute units.
A good rule of thumb is to ask WHY they are performing this, what outcome/goal is trying to be reached.