Stretch ! Stretch ! Stretch !
Calf stretching ( Gastrocnemius ) stretch, this video is for Rt Knee i.e. the leg which is at the back.
Muscle stretching done only in the correct form is helpful and that too if the stretch is held for 10 secs at least.
Repeat these exercises for at least 5-10 times as per your flexibility and allow the muscles to relax especially for athletes and weekend warriors.
Non professional players are more prone for injuries especially as they have lesser time to play and still lesser for a proper warm up and cool down so usually such players rush to courts / field to play without stretching muscles and joints which makes them prone for injuries during play.