Shoulders (2 Points)

1. Keep Your Head Up: Maintain a forward-facing position with your shoulders.
2. Extend Your Shoulders, Avoid Hunching: Keep your arms straight and extended forward to stretch your shoulders and prevent hunching.

Core (3 Points)

1. Engage Your Core: Keep your abdominal core tight throughout the movement, like a coiled spring. Engage your core as you squat down and maintain this tension when rising up. This tightness is crucial for maintaining proper form.
2. Sit Back: Initiate the squat by sitting back as if you're lowering onto a chair, then bend your knees. This engages your glutes and hamstrings effectively.
3. Protect Your Lower Back: When rising, avoid thrusting your hips too forcefully, as excessive strain on the lower back can lead to discomfort and injury.

Legs (3 Points)

1. Squat Properly to Spare Your Knees: Lower your hips to a point where your hip joint is lower than your knee joint by about two to three centimeters, with your thighs parallel to the ground. This balanced alignment minimizes stress on the knees, ensuring comfort and safety. Remember, engage your core when rising, rather than relying solely on your thighs.
2. Foot Position: Stand with your feet slightly wider than shoulder-width apart, toes pointed outward about 20 degrees. Ensure that your knees do not extend beyond your toes, focusing on minimizing stress on the knees.
3. Strengthen Your Legs: To maximize leg strength, aim for a near-complete squat position or perform squats at an extremely slow pace.

In Summary: 

Bodyweight squats not only target the legs but also engage the core and glutes, enhancing stability and strength for easier walking and running. Additionally, they promote increased muscle mass and can boost overall lung capacity, especially when performed for longer durations or with higher repetitions.

By focusing on these key pointers, you can perform bodyweight squats effectively and safely, reaping the many benefits they offer for your lower body strength and overall fitness.