**Core Concept**
Shin splints, or medial tibial stress syndrome (MTSS), is a common overuse injury in athletes and individuals with repetitive stress on the lower leg. It is characterized by pain and tenderness along the medial aspect of the tibia, often exacerbated by physical activity.

**Why the Correct Answer is Right**
The pain and tenderness in the postero-medial aspect of the legs are classic symptoms of MTSS. This condition occurs due to repetitive stress and strain on the medial aspect of the tibia, leading to inflammation of the periosteum and surrounding soft tissues. The involvement of both legs, the presence of acute point tenderness, and the exacerbation of pain with physical activity further support this diagnosis.

**Why Each Wrong Option is Incorrect**
* **Option A:** Stress fractures, while also a common overuse injury, typically present with more localized pain and tenderness, often accompanied by swelling and ecchymosis.
* **Option B:** Compartment syndrome, a serious condition requiring prompt medical attention, would typically present with more severe pain, paresthesias, and a palpable "pseudotumor" in the affected compartment.
* **Option D:** Popliteal artery entrapment syndrome, a rare condition, would typically present with more severe symptoms, including claudication, ischemic pain, and possibly even loss of pulse in the affected limb.

**Clinical Pearl / High-Yield Fact**
When evaluating a patient with lower leg pain, it's essential to consider the history of physical activity and repetitive stress, as well as the presence of point tenderness and pain exacerbation with movement. A thorough physical examination and imaging studies (e.g., X-rays, ultrasound) can help differentiate between various causes of lower leg pain.

**Correct Answer:** C.