Effective exercises for developing quadriceps include: leg presses, leg extensions, lunges, and weighted bench presses.

2. Leg press (performed on a multi-strength rack)

Instructions: Lie supine under the leg press rack, and kick the weights on the leg press rack upwards with both legs until they are fully extended. Repeat this exercise.

Key points: With both knees fully bent, control the center of gravity of the weight on the leg press rack with both feet, slowly straighten the leg, and then slowly lower it, so that the quadriceps (extensors) and hamstrings (flexors) are deeply stimulated.

Breathing: Breathe naturally with light weights, and pay attention to inhaling when exerting force and exhaling when relaxing with heavy weights.

Note: Leg press is an excellent exercise for strengthening leg muscles. Because you lie on your back, the burden on your lower back is minimal, making it especially suitable for those with lower back injuries who want to train their legs. It is also suitable for bodybuilders, as they need well-developed thighs and a slender waist.

Squats can effectively develop thigh muscles, but they also have a significant impact on the waist and hips, making them unsuitable for individuals with thick waists and large hips.

3. Leg push-out (leg extension)

Instructions: Sit on the exercise machine bench with your legs bent and pressing against the machine. Slowly push forward until your knees are fully extended. Repeat this exercise.

Key point: Keep the angle of your knees below 90° for the best effect on strengthening your quadriceps.

After straightening your leg, slowly lower it back and then add weight plates. This is beneficial for exercising the hamstring muscles.

Note: The two exercises above can effectively develop the quadriceps and hamstrings without putting any strain on the lower back. Therefore, they can effectively prevent lower back muscle injuries and are especially suitable for people with weak lower back strength or lower back injuries to persist in leg strength training.

Beamon (USA), the famous former world record holder in long jump, loved this exercise. He insisted on doing the leg push-out exercise three times a week, which gave him strong legs. His world record of 8.90m in long jump stood for 14 years.

4. Lunge

How to do it: Stand out of the squat rack with a barbell on your shoulders or chest, spread your legs apart into a lunge position, then bend your knees and press down to the depth you can bear, then straighten your legs, and finally bring your legs back.

Key points: When carrying a weight, be sure to keep your chest up and your back tight. When squatting, shift your weight slightly forward onto your front leg, bend your back leg, and push your hips forward and down.

Breathing: Inhale while in a lunge position, and exhale after standing up.

5. Weighted bench press

Method: With weights on your shoulders (barbell, weight plates, sandbags), place one leg on a stool about 50-60cm high, and support yourself on the ground with the other leg. Then perform leg flexion and extension movements to straighten the leg. Continue flexion and extension movements until you are standing on the stool with one leg. Repeat this exercise.

Key points: Keep your upper body straight, fully extend the legs supporting you on the stool, and finally do heel raises, using as little force as possible to push or extend the other leg.

Breathing: Take a breath before stepping onto the stool, then inhale as you push off, and exhale as you step down.

Note: Weighted bench presses are not only a good exercise for developing the quadriceps, but also an excellent exercise for developing jumping ability, as confirmed by experimental research institutes in the United States, the former Soviet Union, and my country.

6. Seated leg flexion and extension

Instructions: Sit on a soft stool with the inner edge of your knees pressed against the stool surface, and perform leg flexion and extension movements with weights on your feet.

When doing this on a multi-functional exercise machine, first place the backs of both feet firmly against the cylinder of the machine and perform leg flexion and extension movements. To fully stretch the quadriceps, lean your upper body slightly backward as your calves extend, hold the position for a few seconds after straightening, and then return to the starting position to repeat.

Without equipment, two-person resistance training can be performed, in which one person uses both arms to press down on the trainee's fully bent legs, and when the trainee extends forward, the other person presses down forcefully to create resistance.

Key points: Choose a suitable weight for the flexion and extension movements, extend your knee slowly and fully, and lower it slowly as well.

The greater the load, the deeper the knee bends, and the greater the impact on the knee joint, making it more prone to injury and pain. Therefore, it is important to control the training load.

Breathing: Inhale when you exert yourself, and exhale when you relax.

7. Oblique squat

Method: Usually involves a partner performing a slanted squat.

The practitioner holds onto a partner's outstretched hand or a stick or other equipment. It is best to wear a safety belt with a loop around the waist, and then attach a long hook to the loop to hook onto a solid support in the distance. The body slowly leans backward to perform a series of oblique squatting and standing movements, and can also perform oblique squatting movements with the body leaning forward.

Key points: Fall back slowly, keep your arms straight, and make the angle between your body and the ground 45°. Then bend your knees and squat down. When the angle between your thighs and calves is less than 90°, slowly stand up with your legs together.

Breathing: Inhale when squatting, and exhale when standing up.

Note: Squatting is an excellent exercise that has a special effect on preventing and treating conditions such as patellar chondromalacia.

Regular practice of this exercise can strengthen muscles and bones, making leg muscles firm and powerful, thus helping to maintain physical activity and delay aging.

When Mr. Yi Jingting, a painter from Jiangsu Province, was 93 years old, he could still walk 1 kilometer every day, which was praised by everyone. It turned out that he insisted on doing 90 oblique squats every day. Oblique squats made his thigh muscles strong and powerful, thus prolonging his life.

8. Squat with knees together at an angle

How to do it: Squat down with your legs together and knees bent. Use your shoulders to hold the resistance bar of the weight plate, and then use the force of extending your knees to raise the weight plate to an upright position with both knees straight. This exercise can develop the strength of the quadriceps muscles, as well as the muscles and soft tissues around the patella.

You can also practice split squats with your toes raised.

This exercise not only develops the strength of the thigh extensor and adductor muscles, but also the strength of the calf muscles.

Key points: The body must be leaning at an angle, and forcefully push backward and upward.

Breathing: Inhale as you lift your head forward, exhale as you lift your head back, and then adjust your breathing as you straighten your head.