What's the best way to prevent hamstring injury?
How can we best train the posterior chain?
What works best?
What's most functional? What's least?
Let's start with least functional. In my mind any type of machine leg curl is the least functional hamstring exercise possible. We have not done anything like these for twenty years. Whether lying or seated, attempting to use the hamstrings without some type of simultaneous glute involvement is a waste of time from an injury prevention standpoint.
The Shirley Sahrmann idea of “ any time a muscle is injured look for a weak synergist” supports the theory that hamstrings get injured when glutes are weak so, logically strengthening the hamstrings in isolation seems to make little sense from an injury prevention standpoint. Slideboard leg curls can be used to develop the hamstrings in concert with the glutes.
Most functional? A well designed short sprint program might be the most functional injury prevention tool available. Notice three key words, well designed and short.
Tim Gabbett's research has shown that distance matters. Tony Holler's has shown that volume matters, and JB Morin's work has actually described Sprinting as a Vaccine against hamstring strain.
To further stir the pot, Frans Bosch's work has called into question the actual function of the hamstring in sprinting and, has resulted in an increased interest in hamstrings isometrics. “Bosch Iso's” of varying types have become quite popular and, Bosch's idea of the hamstrings as more of an isometric brake than an eccentric control mechanism is a concept that must be considered. ( Note: the difference between Bosch's muscle slack idea and, an eccentric contraction may be small and, of limited training consequence)
Boschs work is somewhat in contrast to the “Nordic” idea that has also become popular. Nordics are an interesting category and, seem to be surrounded by some confusion. In reality Nordics are just a better marketed version of Dr Michael Yessis's glute-ham raise. The plus with “ Nordics” ( another name I hate) is that they don't require equipment. Nordics can be done with a partner or, by securing the heels under something like a dumbbell rack.
Unfortunately, there are two big minuses with Nordics. One, they are generally too difficult for most athletes and as a result are generally performed poorly. Two, the eccentric emphasis can produce extreme soreness. Ninety percent of the Youtube videos I have seen of Nordic type exercises have been poorly done, generally as a result of poor control of the lumbo-pelvic segment.
( I was going to post a bad Youtube video here but, that will hurt some feelings )
One thing is certain. If an athlete can actually do both the eccentric and concentric portions of a true Nordic Leg Curl and or Glute Ham Raise they have extremely strong hamstrings and, probably a lower chance of injury.
The fascination with Nordics and hamstring injury in the international soccer community led to the development of the Nord Board, an extremely expensive proposed solution to the problem of hamstring injury. Although the Nord Bord may be a reasonable idea, it is out of reach of most athletic programs so, it will not be considered here. In fact, the cost of one Nord Bord could outfit a small team facility.
Much like Nordics, glute hams are poorly understood and most often poorly performed. The general downside of the glute ham is the need for some type of specialized equipment. Personally, I'm a fan of the small, lightweight portable glute ham pads but, even these have their drawbacks. But, an athlete that can properly do a glute ham raise will generally have good hamstring strength and a lower chance of injury.
My personal favorite posterior chain exercise is the 1 Leg Straight Leg Deadlift. The 1 Leg Straight Leg Deadlift uses both the glutes and the hamstrings as hip extensors and can be loaded heavily after some practice. Many still refer to this as a single leg Romanian Deadlift but, we refuse to use names like Romanian Deadlift, Bulgarian Split Squat, Nordic Leg Curl or Copenhagen Adductor.
Recently, we have begun to view sled pushes as a functional posterior chain exercise. In the past sled pushes were somewhat randomly used in the " work capacity" area. In the summer of 2018 we moved sled pushing into our strength program and began to treat sled pushes as a type of horizontal push exercise. Charlie Francis discussed this in his book and used the old Universal Gym Leg Press for a sort of posterior chain leg press. In our case, the sled push fills the same bucket.
Another posterior chain exercise that has become popular is the Hip Thrust. I am not a hip thrust fan for a number of reasons.
1- Most of the demos I see lack lumbar control and are more lumbar extension than hip extension.
2- These are heavy and bilateral and not entirely comfortable, even with a thick pad.
However, I do like the unilateral version!
The last piece of the puzzle is actually the most functional approach. As previously mentioned, JB Morin proposed the idea of Sprinting as a Vaccine in his article of the same title. Morin's theory is that nothing may be more functional, specific and preventative than the actual act of sprinting.
This idea, combined with a Tony Holler type approach of timing and recording times weekly, might be the best hamstring injury prevention strategy available.
We have taken to timing 10 yard sprints twice per week, progressing to a Flying 10 with a 5 yard fly ( 15 yards total) and then to a Flying 10 with a 10 yard fly in ( 20 yards total). We generally time 2-3 reps per day / 4-6 per week. The result for us has been zero hamstring pulls and, some remarkable speed increase. Short sprints might just be the most bang for the buck as they prevent injury and, enhance performance. Sprinting has really changed my view on Velocity Based Training. With bad sprinters moving 8 yards per second and, good ones moving more than 10 it seems silly to be worrying about weightroom stuff that is under 2 meters per second.
In a big picture sense, the best overall prevention strategy might be a strength program that incorporates concentric exercises like the 1 Leg Straight Leg Deadlift, isometrics a la Bosch, eccentric emphasis ( think Nordic lowers or eccentric slideboard leg curls) and, a regular dose of timed sprints.
So, the real answer is that there is no one answer. The best prevention program will take pieces of each concept and weave them together into a strong protective blanket.
Important Notes:
Core control matters. The best way to screw up hamstring training is to elicit hamstring contractions without glute contraction and, anterior core control. This means that in order for any of the many hamstring exercises mentioned to be effective, the pelvis must be properly positioned. Athletes must learn to stabilize the lumbar spine before they can truly benefit from hamstring exercises like Bosch Iso's, Nordics or glute hams. Many of the internet videos of athletes performing these exercises completely miss this major key. This means that an understanding of the basics of bridging must precede all of the above.
Sets and reps?- with isometrics and eccentrics I like to keep the sets and reps low. For isometric hamstrings we might start with three 10 sec holds, moving to 15 and twenty over a three week period. For eccentrics we might use 5 sec lowers with 2-3 reps and 2-3 sets.