Mobility and Flexibility

Posted on 21 Dec 2008 21:16

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The following is a series of articles and interviews on mobiltiy versus flexibility written by, or conducted by, Brian Grasso. Although the subject is young athletes, this applies to everyone.

Flexibility for Young Athletes- Q & A with Chris Blake by Brian Grasso

Chris Blake, MA, LATC, CSCS, YCS

Q: What is the difference between Flexibility and Mobility?

A: Flexibility can have two definitions:

1.) The ability of muscle to lengthen during passive movements.
2.) Range of motion about a joint and surrounding musculature during passive movements.

Mobility can also have two ways of being defined. The main definition is the state of being in motion. But this state of motion can be looked at within certain joints (subtalar mobility) or as a physical whole (moving from one position into the next during a run).

Q: Are both important to young athletes or is one more important than the other?

A: This is a great question. Both are important for the older athlete (ages 14-18+) as athletes within this age group tend to show more restrictions with both flexibility and mobility, often times once you take care of the flexibility then you improve mobility. But with the younger athlete (ages 13 and under) I wouldn't place much importance on either one unless there has been a certain injury that limits each.

Q: Are there different kinds of Flexibility, or is bending over to touch my toes and stretch my hammy what all young athletes should be doing?

A: There are seven different ways of going about flexibility:

Ballistic stretching
Dynamic stretching
Active stretching
Passive (or relaxed) stretching
Static stretching
Isometric stretching
PNF stretching

I use dynamic stretching (more like an active movement series of stretches) with most of my youth athletes from as young as 6 years old.

Q: When should young athletes train Flexibility?

A: As I stated, I use dynamic stretching with most of my young athletes. But my goal is not to improve flexibility with the younger athletes because I feel that this is not appropriate. If anything, most children are too flexible until their bones lengthen. I would have athletes start to work with flexibility around 14 years of age for males, 12-13 for females. But again I feel that at that point in time dynamic movements and warm-up periods are ideal for flexibility.

Q: When should they train Mobility?

A: Global Mobility should be an ongoing part of your everyday programming along with movement preparation.

Q: What is the single greatest mistake or myth people make when it comes to Flexibility training?

A: There are actually two mistakes or myths that come to mind. One is that everyone needs to do static stretches to avoid sustaining a muscle injury. To date there has not been any substantial evidence through research or scientific literature that suggests stretching prevents injuries.

The second part that is more of a mistake than anything is having children perform static stretches before athletic contests or games. The contractile properties of a child's musculoskeletal system does not work well with static stretching. But knowing this and then seeing groups of young athletes stretching the way that their coaches did 'back in the day' just does not make any sense. And yet this is still taking place in every youth athletic league throughout this country. Clearly we still have some work to do to make changes.

Flexibility for Young Athletes - Q & A with Bill Hartman by Brian Grasso

Bill Hartman is a Physical Therapist and Sports Performance Coach in Indianapolis, Indiana

Q: What is the difference between Flexibility and Mobility?

A: Technically speaking based on textbook definitions there may be no difference, but I do tend to separate the two.

Your simple textbook definition of flexibility is movement about a joint. I would consider that a more isolative concept by looking at a specific joint's ability to move without any particular context. For instance, if looking at an ankle, how much dorsiflexion, plantar flexion, inversion, and eversion is available.

Mobility requires context and considers motion relative to the rest of the kinetic chain typically in a dynamic situation. For instance, take the same ankle and now identify how much range of motion is available in the performance of a squat or a specific activity like during a change of direction at high speed. Because of the influence of parameters such as available strength, coordination, acceleration/deceleration, tissue stiffness, speed of movement, etc., the available range of motion may very well differ from that found during a direct open chain assessment of range of motion as done in a clinical setting.

You also have to consider how movement at one joint affects another. Fascial relationships tie joints together during movement such that 'slack' can be taken up at one joint resulting in limited movement elsewhere. The overhead squat is an example. An athlete may demonstrate normal hip and shoulder range of motion in isolation, but when an overhead squat is performed hip and shoulder mobility may be limited by connective tissue stiffness.

If I were to give a simple definition to mobility it would be the ability to achieve the desired movement or position under specific conditions.

Are both important to young athletes or is one more important than the other?
You really won't have one without the other because of the mutual influence, but I think if you look at the big picture and my definition above mobility rules because that's what you see on the field or on the court.

If an athlete can't produce a specific amount of range of motion under any circumstances then it's clear that mobility will be affected in specific situations.

Let's stick with the ankle example.

If I can't get an athlete's ankle to evert past neutral under any circumstances then I know that his potential ability to pronate at the ankle and foot and decelerate effectively is going to be compromised. This is going to cause a mobility restriction and result in a compensation at another joint up the kinetic chain. Not only is performance reduced but given enough force, repetition, and time this is a great way to produce an injury resulting in lost training time, game time, or an end to a playing career.

This is a flexibility issue affecting mobility.

The interesting thing is that I may be able to select an ankle mobility exercise, drill, or manually applied mobilization that will improve ankle eversion and therefore improve flexibility AND mobility.

Q: When should young athletes train Flexibility?

A: Only when it is needed. Unnecessary stretching in the extreme can promote joint instability that can result in injury. It can also rob a young athlete of the necessary natural tissue stiffness he may use to assist in performing high speed movements such as throwing, running, and jumping.

Q: When should they train Mobility?

A: Always. Mobility is influenced by coordinated movement which in turn is influenced by strength, speed, tissue quality, fatigue, etc. These qualities are constantly changing especially in the young athlete. Neglecting mobility especially during rapid or sensitive periods of physical development can set back the athlete's performance and set him up for potential injury.

Q: Are there different kinds of Flexibility, or is 'bending over to touch my toes and stretch my hammy' what all young athletes should be doing?

A: Because of all the physical and neurological qualities that influence flexibility, it can be considered a hybrid quality and demonstrated statically, passively, actively, and under specific conditions. Therefore, the type of training selected can be very specific as well.

For instance, it's not uncommon to see a decrease in joint mobility in situations where the athlete is fatigued, so in this case, the athlete should address mobility issues in a fatigued state.

A young athlete with normal hip flexibility at slow speed may find that his stride is abbreviated at high speeds. This athlete should train flexibility with progressive speed to train the nervous system to allow him to demonstrate optimal flexibility during higher speed activities.

What is the single greatest mistake or myth people make when it comes to Flexibility training?
The biggest misunderstanding in my opinion is that the typical forms of static stretching that we all grew up with and flexibility are the same thing. Static stretching is merely one component of a broad system of training. In some cases it may be an appropriate choice, in others, it may be the absolutely wrong choice.

A close second would be that all athletes need to stretch.

Because flexibility is a hybrid quality meaning that it will be influenced by strength, speed, endurance, coordination, and many other abilities, what is necessary for one athlete may not be for another. In fact, choosing the wrong method of training can negatively affect an athlete's performance.

Flexibility for Young Athletes - Q & A with Dr. Kwame Brown by Brian Grasso

Dr. Kwame Brown has a Ph.D. in Neuroscience and is a founding member of the IYCA

Q: What is the difference between Flexibility and Mobility?

A: Well, sometimes this is a confusing issue, as these terms are often used interchangeably. Mobility (also known in some circles as active flexibility) is where we're talking about CONTROL of the body through a larger range of motion. The muscle group says 'I want to move, and I can.' The contrast is passive flexibility, where an outside force will be asking the question, 'Can I stretch you?', and the muscle says 'Yeah, I guess so'. There is no skill here, and it is my belief that those who are hyperflexible (too flexible) without motor control are just as prone to injury as those who are Hypomobile / flexible (not mobile or flexible enough).

Q: Are both important to young athletes or is one more important than the other?

A: I think that, all things being equal, mobility is a far more valuable goal to pursue for our young ones. However, if there is a physical limitation in a certain body area / muscle group, flexibility can certainly be addressed as part of an overall mobility program.

Q: When should young athletes train Flexibility?

A: Again, flexibility should be the goal when there is a specific area that is tighter proportionally than the rest of the body. Although, the first question should be 'Why?', with regard to the cause of the tightness. Many times, we are just dealing with the natural growth process during a growth spurt, where bones outgrow muscle and connective tissue, and there is temporary tightness. We may need to train flexibility here through focused stretching, but always in the context of a well rounded mobility program.

Q: When should they train Mobility?

A: Unless there is a debilitating injury. Always. Throughout development. Period.

Q: Are there different kinds of Flexibility, or is 'bending over to touch my toes and stretch my hammy' what all young athletes should be doing?

A: Absolutely not. The young body should be able to MOVE, and the body should interact smoothly and naturally with the nervous system, not just accept and yield to forces passively.

Q: What is the single greatest mistake or myth people make when it comes to Flexibility training?

The greatest mistake people make when it comes to flexibility is to force a passive stretch. When you force a passive stretch, there is circuitry in the spinal cord that will respond by tightening the muscles. Wait, weren't we trying to RELIEVE the tightness in the muscles? I have seen utterly sadistic attempts by uninformed, performance / ego driven coaches where they would take a young athlete and stretch him or her to the point of tears, actually saying that they wouldn't get flexible unless they fought through the pain. This doesn't create athletic mobility, it injures, tears, and forever alters the tissue.

Flexibility - More Than Stretching by Brian Grasso

Flexibility is a very misunderstood concept.

For starters, flexibility and stretching have long been considered to be the same thing, when in fact, they're not. Performing basic static stretches (like a standard hamstring or calf stretch) can certainly increase the resting length and decrease the tone of a given muscle, but that may have little to no effect on the actual flexibility that a young athlete has.

Flexibility more precisely, refers to the range of motion (ROM) that a given joint can exhibit (as influenced by the muscles surrounding it).

This range of motion, as the term infers, involves movement.

Holding a static hamstring stretch for a certain period of time has no real impact on how well that muscle moves or to what degree it allows the joints that it effects to move.

So why then, do so many youth sport practices start with stretching?

One word:


As parents and coaches, you have been exposed to the 'pre-practice stretching habits' for years and therefore have always assumed them to be right.

Your coaches did that with you.

Their coaches did it with them.

Of course you need to stretch, you may be saying, you have to prepare the body for the work it's about to do.

Well, Yes! But let's look at it from a different perspective for a second.

When you were young, you likely went outside to play with your friends every day in the summer, just like I did. You walked out the front door. Headed around back to grab your bike. Hopped aboard and headed straight for the park. When you got there, the football/soccer/baseball/basketball game had already started, so you jumped right in. And you played. In my case (and maybe yours to) for hours!

But wait a second. How is that possible? You didn't stretch before you started; how did you not fall into a million little pieces, turn to stone, melt or experience any of the other doomsday predictions we feel are going to happen to our kids if they don't stretch before the big game or tonight's practice.

The reality is that stretching likely isn't necessary before activity. I say likely because that often can depend on your age, current fitness level or pre-existing injuries. But with young athletes, it's almost always the case.

Flexibility however, IS important. Flexibility remember, is the range of motion a joint has as influenced by the muscles surrounding it. And believe it or not, flexibility is most enhanced by: Are you ready for it?

Strength training! The stronger a muscle is through a wide range of movements, the greater the range of motion is at the joints that muscle interacts with. I know, strength training limits flexibility.

More dogma, period! Try this exercise as a great flexibility enhancer for young athletes before your next practice or game. It will increase the strength of many of the key muscles in the leg and add to the flexibility of your young athletes:

Leg Raises (4-Quarter):

Lie on your back

Raise one leg straight up in the air, while keeping the other one straight against the ground

Slowly lower your leg towards the side, keeping the knee straight the whole time, until you almost reach the ground

Hold for a couple of seconds (but not too many!)

Raise the leg back up again

Lower again, this time the other way (across your body)

Allow your hips to roll with you and hold the leg above the ground for a couple of seconds

Raise the leg back up again

Lower to the original starting position and repeat with the other leg

Go back and forth between legs for a total of 5-8 reps leg.

Known as 'America's Youth Fitness Coach', Brian Grasso spends all his time training young athletes, children with disabilities and those encumbered with body weight concerns. He has authored two books on the subject and was recently featured in Newsweek magazine for his work in youth fitness and sports training. He has also been named as one of the 'Top 100 Trainers in America' by Men's Health magazine. Brian is the Founder and CEO of the International Youth Conditioning Association and can be contacted through his website -

Related links:

What is Dynamic Mobility?

The Stretching Handbook


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