A client frequently compensates by arching their lower back during a supine straight leg lift. What specific tactile cue can the instructor use to promote deep abdominal engagement and maintain a neutral spine?

The specific tactile cue involves the instructor placing the fingertips of one hand gently underneath the client's lower back, specifically in the lumbar region just above the sacrum. This position allows the instructor to directly sense changes in the natural curvature of the lumbar spine. The instructor then instructs the client to maintain a consistent, light pressure of their lower back against the instructor's fingers throughout the supine straight leg lift, without pressing so hard that the entire back flattens onto the mat. This cue promotes deep abdominal engagement by facilitating the activation of the transversus abdominis, the deepest abdominal muscle, which functions like a natural corset to stabilize the trunk. When the client focuses on maintaining gentle pressure into the fingers, they are primarily engaging this muscle to create subtle intra-abdominal pressure, which provides intrinsic support for the lumbar spine. Maintaining a neutral spine is achieved because the instructor's fingers provide immediate biofeedback. If the client compensates by arching their lower back, the pressure on the fingers will either significantly increase or the space between the client's back and the fingers will expand, indicating a loss of the neutral lumbar curve into excessive lordosis. Conversely, if the client posteriorly tilts their pelvis and flattens their back excessively, the pressure will be too firm. The consistent tactile feedback teaches the client to feel and sustain the precise level of deep abdominal engagement required to keep the natural, slight inward curve of the lumbar spine stable and unmoving while the leg performs the straight leg lift.