Leg Curls.............

https://www.tmuscle.com/free_online_article_issue/issue_630#reader-mailThat wasn't so bad, was it?It's a little annoying because the original question wasn't coded with the intent for a bodybuilding-only goal.  Of course you would use leg curls if you are happy or making money going after a bodybuilding goal.I do know that Thomas Phillips, his wife, Jody, and all the guys I train with 5 days a week all came home with trophies without any machine not called a GHR or Reverse Hyper.  https://fitforlifemarlboro.blogspot.com/ .But my friend, Bret Contreras (https://bretcontreras.wordpress.com/) who has been around the Internet community much longer than I says there's no such thing as bad publicity.  Please remember me, Bodybuilding guys, when my DVD comes out.............So from all this,  a recent message I got from a young trainer, was something that I wanted to put through here to share these clarifications and thoughts.In regards to the use of the leg curl machine, I was wondering if you could expand a little bit on why you would not want to train the movement in absence of hip extension........, I have some ideas as to why but I figured I would ask.  I am not trying to question you, I actually greatly appreciate your thought process in training and am only trying to get a better understanding.  Your answer will not be posted on any blogs nor will I call you "extraordinaire."My thought process is a little less complex when it comes to this exercise on the machine.  I see very few clients who I would feel could even perform this exercise correctly with little to no weight, most have very short/stiff rectus and when doing a modified thomas test show this as well as when testing in prone knee flexion the hips move and cause the low back to give motion.  Even with the modification of a "brace" at times this is a rough task, so I have a hard time believing that this is a good exercise for most people given that alone.  Now I know that the machine would flex the hips a little and that this may help take rectus out of the movement to some degree but then again most even when cued to "brace" will not be strong enough stop this hip movement. My guess is your thought process is more refined and deals with movement patterns and wanting to take training time to maximize and reinforce "optimal movement" in the fundamental base of the performance pyramid and then when it comes to power or skill be more specific with training, not using machines.Here's where my head is at this Sunday evening...............1.  Isolated movement and resistance training based on kinesiology are not unsafe at the muscular level during the exercise.  It is quite the opposite.  You are probably very safe.  The machine takes up all of your stability needs, and assuming you "fit" into the machine, something I think is rare, training the muscle you want is pretty much dummy-proof.2.  Let's talk about the machine(s) in the first place because just like just about everybody in our profession, I grew up in a big box gym using bodybuilding programs and reading Flex, Ironman, and Muscle & Fitness.  Not all machines are created the same, and I mentioned before "fitting" into the machine.  I mean how can I @ 5'4", 180 fairly thick and a normal sized person always use the same machine.  They aren't all going to have adjustable levers that compliment where the joints are.  Moving the way the machine wants you to move is hardly a good idea even if you are attacking hypertrophy only.  But again, if you do fit in the machine, it is not unsafe, and it is a good idea, probably the best idea, to funnel all your effort into isolated strength and/or hypertrophy.3.  Machines continue to be different in their setup.  The leg attachments can complement or confuse different body types even if the knee joint angle lines up.  My opinion is that unfortunately moves that feel hard to do gain status in the bodybuilding lore as I think there is a thought that if it's hard, it must be good.  Rather I think this is the body's way of rejecting the movement as "wrong."4.  Also please consider that there are flat benches and benches humped @ the waist.  Your concern for ideal execution being challenged from tight front sides via hip flexors is very real, and this is why they make benches that slack the front side.  Now is a flat bench the machine's fault, or is it the person coming to the machine's fault?  You are right that the knee flexion will be met with a compensation of lumbar extension.  This is how you can see a Type B Lower Crossed with tight hamstrings.  Bracing can not outrun the tight hip flexors, especially when they are slacked from a machine meant to make the curl easier.5.  To answer the original question about not training knee flexion without hip extension, that is based on the basics on how the body moves.  Whenever we see knee flexion in function, it is accompanied by forceful hip extension.  We use the hip flexion to drive the frictioned foot through the toes and propel forward.  Try walking without hip extension.  You will shuffle and festinate or be all hunched over.  The hamstrings are hip extenders, not knee flexors.  Knee flexion occurs as an eccentric action of the anterior chain.  Is there some random movement like in wrestling or fighting where you flexion the knee concentrically? Sure.  But that's why there's GHR which leaves nothing on the table in terms of hip extension and core.  I guess I would always ask before using a machine if there is another option.  Most legitimate moves can be regressed for the right person, and if it can't be, then you're just not there yet.  Get there.6.  The bottom line is that all machines create irrelevant strength.  There is no ability to recreate the expressions of force capabilities of the limbs without the supported environment.  The arms and legs are writing legs that the body's stability mechanisms such as the spine can't cash.  Is there a metabolic response?  Yes.  Is there a hypertrophy response?  Yes.  Can I go on?  Yes.  Do these responses challenge my claim of irrelevancy?  Probably, but there is nothing I can't accomplish without a machine that I can with one.  It will take more teaching, a slower and more authentic progression, and a lifetime of fitness possibilities.  God made machines to make life easier.  I don't want easy when we are training.  I want authentic and and natural so whatever we build will be a foundation for anything else we do.7.  Train on machines and maybe be safe then get hurt in the real world.  Stop it.  And don't go telling me you don't see 911 showing up every 10 minutes to your gym.  You only know how to look for car accidents.  Try learning how to look for the tread on the tires and alignment of the axles and see where people wind up when they are 40 and 50, and you're out of the profession.  If you are a serious bodybuilder, then go get 'em.  Otherwise, enough please.