Tension, muscle relaxation in runners

Even gentle jogging helps to exercise your muscles and many doctors recommend stretching them both before and after exercise. Exercise can shorten a person's muscles, reducing mobility over time. Stretching keeps the muscles in the upper body flexible, so that the muscles and joints are in a state of maximum motion.
Most doctors also recommend warming up by stretching before doing running exercises. Muscles respond better to stress caused by the body when they are warmed up. Warm-up can be as simple as walking for 5 to 10 minutes, just enough to get blood circulating throughout the body.

Here are 10 key muscle zones for runners to stretch and the stretches you need to do to keep them strong.

2.1. Quadriceps The quadriceps, quadriceps muscle covers most of the front and sides of your thighs. Stretching the quadriceps is super important if you're running up or down hills. To stretch them:
Stand straight and pull your legs back with the corresponding hands. Squeeze the pelvis and pull the shin toward the thigh. Keep your knees pointing down as you do this move to protect your knee joint. Hold for at least 30 seconds, then switch sides. You can also use a chair to balance yourself. You should feel this stretch in the front of your thighs and from your hips down to your knees.
2.2. Hamstring muscle The hamstring muscle makes up the back of the thigh, extending from the hip to the knee. For this stretch:
Sit on the ground while extending your left leg. Move your right foot toward your inner thigh, so that it touches the top of your left leg, if possible. Lean forward, bending but not rounding your back and waist toward your left foot as if with your toes. Hold for at least 30 seconds. Repeat with the other leg. Be careful not to pull your toes back during this stretch. You should feel it on the back of your leg, from the knee to the buttock.
2.3. Calves The calf muscle on the back of the shin is an important area to pay attention to after running. Poor calf flexibility can leave you vulnerable to pain and injury.
To stretch your calf muscles:
Stand with your right foot behind your left. Bend your left leg forward while keeping your right leg straight. Make sure not to bend your right knee and keep your right foot firmly on the ground, facing straight ahead. Keep your back straight and hold the pose for at least 30 seconds. Repeat with the other leg. You should feel this stretch anywhere from behind the knee down to the ankle.

2.4. The iliotibial band (ITB) runs on the outside of your thigh between your hip and shin. People who are new to running too much can easily injure this area. To do this:
Stand near a wall or something you can use for balance. Cross left ankle behind right ankle. While balancing with your right arm, extend your left arm overhead. Lean forward and reach towards your right side. Hold for at least 30 seconds and repeat with the other leg. As your left ankle crosses behind your right ankle and leans to the right, you should feel a stretch in your left leg. 2.5. The pyramidal muscle, a muscle in the glutes that helps stabilize the hips and pelvis. You use this muscle every time you take a step. To stretch the pyramids:
Lie on your back with both knees bent and feet on the floor. Pull your right knee up close to your chest. Grasp the knee with the left hand and pull it up towards the left shoulder. Hold for 10-20 seconds and then repeat on the other side. You should feel this stretch in your buttocks and near your hips. 2.6. Lumbar muscle The lumbar muscle is located at the front of your spine and connects your lower back to your upper thighs. To stretch this muscle:
Start by bringing your right leg forward so that you are in a crouched position. Keep your chest and shoulders upright and push your pelvis back, while squeezing your glutes. Lean forward slightly until you feel a stretch and hold for at least 30 seconds. Switch sides. You should feel a stretch in the front of your hips on your back leg. 2.7. The glutes The body's glutes, or "buttock muscles" as they are commonly called, make up the glutes and play an important role in runners. Strengthening and stretching your glutes is important for improving your running performance. To do this:
Lie on your back, bend your knees while placing your feet on the floor. Cross the ankle of the right leg over the left knee. Grab your left knee behind and bring your leg toward your chest. Hold for at least 30 seconds, then switch sides. You will feel a stretch in your buttocks.

2.8. Your groin is the part of your body that lies between your abdomen and thighs, generally the hips. To stretch your groin:
Stand with your feet wide apart in a wide stance. Without moving your left leg, lean to the right and bend your right knee until you feel a stretch. Hold for 10-20 seconds, then switch sides. You should feel a stretch in your inner thighs. 2.9. Spinal strain Harder running surfaces, like sidewalks, put extra pressure on the spine and can cause tension and pain. To lengthen your entire spine:
Lie on your left side. Keep your left leg straight and bend your right knee so your foot touches your chest. Rotate right leg until knee touches the ground in front of left foot. Rotate your right arm, head, and upper back to the right until you feel a stretch. Hold for 10-20 seconds and repeat on the opposite side. You will feel your spine stretch. 2.10. Lower back muscles The lower back is another part of the body that runners need to be aware of. To stretch your lower back:
Lie on your back. Grab both knees and pull them up close to your chest until you feel a stretch. Hold for 20 seconds. Stretch safely

Reference source: healthline.com