You’re doing this as a warm-up, not an intense exercise. Stick to moderate speed.
Don’t push back with force. Make it a slight flick that brings your foot up for only a moment. There is no need to bring your knee forward for this exercise. Keep your upper leg close to vertical.
Stand sideways to a wall and put your hand out against it for support. Swing the leg closest to the wall forward and back as high as you can. Do not hold your leg in an upright position. Turn around and put your other hand against the wall. Repeat with the other leg.
Lie flat on the ground with your arms straight out, in a T shape. Swing your leg toward your opposite arm, keeping both shoulders on the ground. Return that leg immediately to the ground. Repeat the exercise with alternating legs.
Stand up straight with your feet wide apart. Bend over and touch your right hand to your right foot. Hold for 20-30 seconds. Repeat 10–20 times, alternating feet.