Which muscle would likely be short and hypertonic in a client with mild lateral rotation of both legs after running a marathon?

In the context of mild lateral rotation of both legs following a marathon, the piriformis muscle is likely to be short and hypertonic. The piriformis is a deep hip muscle that helps with lateral rotation of the hip and abduction of the thigh when the hip is flexed. During activities such as running, especially over long distances like a marathon, the hip muscles can become tense and overworked, leading to an increase in muscle tone.

When the legs are positioned in a mild lateral rotation, it suggests that the hip external rotators, including the piriformis, may be engaged more than usual. If these muscles become short and overactive due to repetitive use, they can contribute to persistent tension and discomfort.

In contrast, the other muscles listed, such as the hamstrings and quadriceps, primarily function in flexion and extension of the knee and hip rather than rotation. The gastrocnemius, which is a calf muscle, also does not play a direct role in hip rotation and is primarily involved in plantar flexion of the foot. Thus, these muscles are less likely to exhibit hypertonicity and tightness specifically associated with lateral rotation after running a marathon.