The Natural Sit-to-Stand-Walk of the Frail

Abstract

Sit-to-stand-walk (STW) is a complex task that sequentially transitions an individual from sitting through standing to walking. In this study we evaluate the unrestricted, natural pattern of movement of the STW task from a hospital bed of 21 (5 Female, 16 Male) frail (MFS > 55) adults (68.0±11.2 years) with a total of 144 unique trials. Bed height (low, medium, high) and bed rail condition (no rails, Hill-Rom®, Stryker®), were varied, generating 9 potential trial types per participant. A new STW phase, Stand Preparation, is defined specifically for the frail that occurs just prior to the Flexion Momentum Phase, also named here as the Stand Initiation Phase. In conjunction with the newly defined Stand Preparation Phase, movements used by the frail to maintain or regain balance during STW task are newly defined as corrective behaviors (CBs). These include hand, foot, leg and torso CBs. In 144 unique STW trials, 678 hand and foot CBs were observed and recorded. The most frequent CB type was the hand CB (335), followed by the foot CB (316). A coding system for use in the kinematic analysis of the natural STW task was developed that identifies CBs through visual observation. In addition, a 3D biomechanical model was generated from collected marker position data and will be used in future biomechanical analyses with the visually observed CB data. The Stand Initiation Phase contained the most CBs. Significant factors included bed height and phase, as well as their interaction (all with p-values ≤ 0.006). This is the first study to establish a more accurate and complete STW of the frail elderly, as well as to define CBs employed during their natural STW. The dataset from this coding system, along with the newly established STW phases of the frail, are currently being used for further analyses to determine the exact timing and position of fall initiations during STW of the frail.