Hamstring strains are among some of the most common injuries in sports.  What we know from research is that quite a few hamstring strains result during the terminal phase of gait while running at high speeds.  When we test of isometric hamstring strength during evaluations, testing the patient prone at 15 and 90 degrees(hip stabilized at 0 degrees) helps us to differentiate where the most weakness is occurring in knee flexion.  Furthermore, because the hamstrings assist in hip extension, isometric strength testing of hip extension with the knee in 0 and 90 degrees of flexion is beneficial when creating treatment plans.  
Hamstring walkouts is an exercise that can be very effective in the rehabilitation of hamstring strains.  This exercise works the hamstring musculature in multiple ranges of knee flexion while simultaneously holding hip extension.  Because the hamstrings assist in hip extension this exercise ensures strength throughout the hamstring.    
Instruct the patient to lie hookline.  Have them perform a bridge to begin.  Cue them to hold that bridge and begin to walk out with their heels slowly.  Once they reach near full knee extension instruct them to return, still maintaining the bridge and using their heels to slowly flex their knees.  

The Nordic Hamstring Curl is a hamstring strengthening exercise that is vital to an athlete’s rehabilitation or offseason strengthening program.  Hamstring strains are among some of the most common injuries in sports.  Unfortunately, many times we do not have access to a partner to stabilize our ankles, which can prevent one from doing this exercise.  In the video below I will show you how you can use standard equipment in most gyms to perform the Nordic Curl without needing a partner. 

Place your ankles underneath the bench.  Put your arms across your chest and keep your back straight.  Slowly lower yourself as far as you can go down and then catch yourself at the bottom to help assist you coming back up.  To progress this exercise try to come back up without the assistance of your arms. 

The single leg hip abductor squat is an advanced exercise that works on balance, strengthening, and function.  This is a great exercise for athletes because it works both hip abductors simultaneously.  Many times we give exercises that work the hip abductors on a single side which is beneficial, however, how many times does an athlete use only one side of their hip abductors during a game?  The exercise will translate over functionally for return to play while challenging the athlete.  Make sure to look for any movement deficits(such as my hip hike in the video below) when the athlete begins to squat.