A monitoring device includes a sensor band configured to be secured around an appendage of a subject, and a sensing element movably secured to the sensor band via a biasing element. The sensor band has a first mass, and the sensing element has a second mass that is less than the first mass. The biasing element is configured to urge the sensing element into contact with a portion of the appendage, and the biasing element decouples motion of the band from the sensing element. A monitoring device includes a band that is configured to be secured around an appendage of a subject. One or more biasing elements extend outwardly from the band inner surface and are configured to contact the appendage. A sensing element is secured to the band inner surface. The one or more biasing elements decouples motion of the band from the sensing element.