Foam Rolling

After a lengthy hiatus, here we are back again. Today we have a special guest Post by Ben Pickard, UW Kiniesiology student, on the basics of foam rolling and self myofascial release.

General Information

Foam-rolling is an increasingly popular method of Self-Myofascial Release, or SMR. This is essentially an affordable, convenient alternative to massage therapy and can be easily used to treat larger groups of athletes in shorter periods of time.

Though it can be painful, and will be especially difficult to endure for the first few uses, foam rolling is an extremely value addition to any stretching and mobility program. After a short period of regular use, the initial pain felt when rolling will disappear and the benefits will begin to show more prominently. Generally being 36” long and 5-6” in diameter, foam rollers range in density from quite soft, which tend to deteriorate quickly, to very hard which are also the most durable and effective. For the most cost effective and hardest rollers a piece of PVC works quite well, with the smaller the diameter the deeper the release. For smaller specific areas a lacrosse ball is extremely effective as well, but will be initially quite difficult to tolerate.

Foam-rolling works to relieve muscle pain and soreness, decrease joint stress, increase joint and muscle mobility and can correct muscular imbalances by returning shortened muscles to a normal length. Foam-rolling works via a phenomenon referred to as ‘autogenic inhibition’. Basically, there are two types of receptors located in skeletal muscles. Found running parallel to the muscle fibres, the first are muscle spindles and they are sensitive to change and rate of change of length in muscle length (if you are familiar with the stretch reflex, it is due to these receptors). They are responsible for shortening the length of a muscle, and this can be the cause of great discomfort and pain with tight muscles. The second type is called Golgi Tendon Organs (GTOs), which are found where the muscle meets the tendon, and they are sensitive to change and rate of change of tension in muscles. Increased tension is achieved through the pressure applied by foam-rolling, and once tension exceeds a given threshold the GTOs inhibit the muscle spindles from shortening the muscle, allowing it to relax and stretch out. 

Additionally, foam-rolling has the benefits of breaking down any scar tissue and ‘knots’ that can develop in the muscle fascia, the connective tissue that surrounds your muscles and underlying muscle fibres. With the breakdown of scar tissue and knots, the muscles regain the ability to move smoothly resulting in improved function and decreasing the risk or injury.

Execution

It is extremely simple to foam-roll. Place the roller on the floor and the athlete will lay the body segment of interest on top of it, with the roller perpendicular to the direction of the muscle fibres. Beginning gently, the athlete will roll back and forth on the roller ensuring they go from one end of the muscle fibre to the other. The athlete can increase or decrease the pressure by using their arms and legs to support their bodyweight. There are many methods to foam roll; slow rolls all the way up and down a muscle, going up two inches and back down one, faster and lighter rolls vs. slow and heavy ones,  and any others that suit a particular athlete. In any case, it is beneficial to stop and apply a constant pressure to any areas of particular discomfort for about 20-30s, or when the tightness subsides. It is also acceptable to do short, fast and heavy rolls on these areas as well. Attempts should be made to take deep, regular breaths when rolling. 

Foam-rolling has the greatest benefits when combined with a static stretching program, completed post-training when the muscles are warm and mobile. Rolling should precede stretching, as the rolling will help to loosen the muscles and the stretching will help maintain an increased length. It is acceptable to roll prior to training, but this should be done at the athlete’s discretion and only following a proper warm-up. Rolling is not an adequate substitute to a dynamic stretching or mobility program.

The following depict how to roll out some common areas, courtesy of Greg Everett’s Olympic Weightlifting, A Complete Guide for Coaches and Athletes.

References

Everett, Greg. Olympic Lifting, A Complete Guide for Coaches and Athletes. 

http://www.performbetter.com/catalog/matriarch/MultiPiecePage.asp_Q_PageID_E_91_A_PageName_E_ArticleMyofacialRelease

Mechanics of Motion

In previous articles I discussed the role of kinetic links and rotational quantities in human movement.  As the human body can be modelled as series of joints and members, each movement of a limb segment can be expressed as a rotation of that member about its joint - thus the movement can be associated with rotational quantities (angular displacement, velocity and acceleration).  However, movement of the body is not in isolation; very rarely will only one limb segment have to move.  Usually segments move in unison, or move as a result of movement further up or down the kinetic chain.  This is where kinetic links come into play - studying kinetic links shows us that displacement at one end will often lead to displacement throughout the entire link.

Taking another few steps back we can examine just the basics of Newtonian Mechanics - the laws of physics which govern every single physical object on this planet.  Everything from a book resting on a table to a weightlifter clean and jerking 200 kg, these can all be explained with basic theories of static and dynamic force analysis.

Basics

Force can be defined through Newton's 2nd Law with the general equation F = ma; there m is mass and a is acceleration of the object.  In metric units, mass is defined through kg's and acceleration through m/s^2.  Thus force is defined with the units kg.m/s^2, or Newtons (N).

All objects whether moving or staying still will have a force exerted on them at all times.  According to Newton's Third Law:

To every action there is always an equal and opposite reaction: or the forces of two bodies on each other are always equal and are directed in opposite directions.

If you push on a wall, the wall is pushing right back on you with the exact same amount of force you applied.

Forces can come from a variety of sources: applied, frictional, gravitational; just to name a few. Here's a brief outline of how they are created.

Applied Force:  A force generated by an object or person onto another object or person.  This can include pushing or pulling on something.  If you are pushing on a wall with 10 N of force, that is an applied force of 10 N.

Normal Force:  The opposite and equal force explained by Newton's Third Law, this force counteracts applied force.  In a static situation this counter force is what keeps an object from moving.

Gravitational Force:  A force generated through gravitational pull.  Any object through in the Earth's atmosphere experiences a constant gravitational acceleration of g = 9.8 m/s^2.  Thus given the equation in the previous section if we know an object's mass we can calculate its gravitational force by using its mass and gravitational acceleration (F = mg).

Friction Force:  Force on an object due to friction when being dragged across a surface.  Every surface-surface interface has an associated coefficient of friction (u).  Combined with the normal force (normal to the gravitational force), we can calculate friction force with the equation Ff = u*Fn.

Stay Still

One scenario of force analysis is the static situation.  In Statics, there is no net acceleration of the object; everything stays still and unmoving.  Even though an object at rest looks to be completely unperturbed there can still be a variety of forces acting upon it; its just that the sum of all these forces in their respective planes net is zero.  If I have a 10 kg plate sitting on a table, what are the forces at play?  If nothing is pushing it across the table then there are no forces acting in the horizontal direction.  In the vertical direction there is the gravitational force acting upon it (Fg = 10*9.8) and attempting to pull it down to Earth.  Since the plate is completely at rest then there has to be some sort of counteractive force to resist the downward gravitational force.  If you even read the last section you'll know this is the normal force - the force which acts in an equal and opposite direction as postulated by Newton''s 3rd Law.  Thus, to keep this 10 kg plate unmoving in the vertical direction, the normal force acting from the table to the plate must equal the force of gravity acting from the plate to the table.

We can quantify static scenarios through Newton's 2nd Law, F = ma.  For this scenarios as the object is unmoving, acceleration is equal to zero.  Thus, the sum of all forces will be equal to zero (F = 0).  Through a Free Body Diagram (FBD) we can simplify any situation into a diagram of vectors and geometric shapes, and equate them using Newton's 2nd Law.

Moving On

While static force analysis works for non-moving situations most of our human activity is performed while moving.  Any force analysis situation we encounter is known as a dynamic scenario.  Going back to Newton's 2nd Law, in dynamic situations we now have an acceleration value to attach to the equation, thus the sum of all net forces will be equal to mass multiplied by acceleration of the system (F = ma).

So how do we get in dynamic scenarios?  For motion to occur we must overcome the initial force of an object resisting motion; known as Newton's 1st Law, or the Law of Inertia.  Every single object, from a box on the floor to our own limb segments, has its own inertia which is related to its mass.  To get an object to start moving we must apply enough external force to overcome its inertia.  For those who've pushed a car knows that feeling of that initial resistance where we start applying high amounts of force and the car barely gets rocking.  Up until the point where the car actually moves we haven't overcome its inertia yet.  However notice as you overcome inertia the car starts moving and as you push it gets easier to move the car (although this has more to do with friction of the axle).

For these dynamic scenarios, applied forces are no longer balanced like in the static scenario.  When not moving, forces in a plane of motion will net to equal zero - hence no movement.  However since the dynamic scenario has the object moving, one direction of force will be greater than its opposing amount. For example, if I throw a ball straight up in the air let's look at the forces at hand.  Assuming no horizontal displacement, there are no horizontal applied forces.  In the vertical direction we have the gravitational force of the ball acting downward.  Acting up, we have the the applied force of my hand throwing the ball.  Just how much force is acting on the ball?  To overcome the ball's inertia, it must be greater than the downward gravitational force.  Since the ball's net displacement and acceleration is going upward, the upward throwing force applied must therefore be greater than the downward gravitational force

Taking this one step further, knowing the forces applied we can figure out the acceleration of the object. Or, knowing the acceleration we want to achieve we can calculate how much force we need to apply.  The forces calculated in the static scenario shows the force required to keep an object at rest.  If I'm trying to push upward on a barbell and I know this barbell weighs 100 kg (Fg = 980 N), I know an upward force of 980 N will keep this barbell at rest.  However, once I apply 981 N of force I now have an imbalance in forces; my upward pressing force is greater than the downward gravitational force.  Since F = ma, a positive force can be correlated to a positive acceleration - if I have a 10 kg object with a measured net force of 100 N I can calculate than in order for this to be true the acceleration must be 10 m/s^2 (a = F/m; a = 100/10), as to not violate Newton's 2nd Law.

As an aside we should look at the definition of displacement, velocity and acceleration.  Displacement is defined as the net distance moved.  If I start off standing in a room and walk 10 m forward, my net displacement is 10 m [forward].  Displacement can be a negative value but only because of the sign convention (the way we define positive movement).

Velocity is defined as the rate of displacement; V = D/t.  If I walk those same 10 m and take 5 seconds to do so my velocity is equal to 2 m/s.  If I have a negative velocity the object is also moving backwards, the same direction of the displacement.

Acceleration is defined as the rate of velocity; how quickly or slowly an object moves (a = v/t).  This can be useful in determining changes in speed such as with a car, or bar velocity on a bench press.  The big deal about acceleration is that I can have a negative acceleration but still have an object moving in a positive direction.  How you ask?  Acceleration is the rate of velocity; if I have an object moving at 2 m/s and 1 second later it moves at 4 m/s, its acceleration is 2 m/s^2 (a = v2-v1/t = 4-2/1 = 2 m/s^2).  If at the next instance it goes from 4 m/s to 1 m/s one second later its acceleration is -3 m/s^2 (a = 1-4/1 = -3 m/s^2).  Thus an object can still be moving forward but if it is slowing down its acceleration is negative.

Why is this important?  When used in Newton's 2nd Law; F = ma; we are calculating static force as the force applied just before the object moves - a minutia of added force will get this object moving.  When calculating for dynamic situations we can count initial velocity is zero (not moving) to some positive value (positive).  Thus any time we start going from unmoving to moving our acceleration is going to be positive.  There will be times where as we move along on a path our acceleration will be negative but I'll get into that later on.

Application

So how does this relate to what you're all here for (athletics)?  Simple - everything physical you do on Earth is related to these laws.  Nothing can ever disrupt these laws of motion lest something severely drastic occur (such as the Large Hadron Collider tearing a new black hole in space and disrupts Earth's gravitational pull).

Damn you!

Look at a person dragging a sled.  Assuming we know the frictional static and kinetic coefficients of friction between the ground and sled, weight of sled and force applied by the sled dragger we can calculate the acceleration of the sled.  Or, if we want to train the sled dragger to be explosive for his sport, we can calculate the amount of force he needs to exert in order to keep this sled moving with positive acceleration.

Another example of dynamic scenarios is the Dynamic Effort method of lifting, popularized by Westside Barbell.  The Dynamic Effort method consists of lifting submaximal weights while exerting maximal levels of force to the bar.  For example let's say your best bench press is 500 lbs.  For a dynamic effort day you may use 300 lbs of weight, but move the bar with 500 lbs of applied force.  Due to the unbalanced forces (300 lbs of downward weight vs. 500 lbs of upward applied force) we are positively accelerating the bar, thus fulfilling the purpose of the dynamic effort method.  By learning how to move the bar with maximal acceleration a weightlifter can learn how to apply maximal force and lift near 1 rep max weights.  However, if the same weightlifter were to practice low rep work with 455 lbs, he may not even apply 500 lbs of force to the bar once (instead, somewhere around 456 or more lbs, due to low velocity of the weight) and on competition day the weightlifter may no longer be able to apply 500 lbs of force to a barbell.  It can be concluded that the greater acceleration we apply to the bar, the greater force we are applying.  Learning to apply maximal force to the bar will help us lift heavier weights.  Thus, knowing methods on how to apply maximal force can benefit the weightlifter come competition time.

As a follow up we'll be looking at the physics of weightlifting bands and how they force the lifter to increase acceleration through the lift.




References:

http://csep10.phys.utk.edu/astr161/lect/history/newton3laws.html
http://www.physicsclassroom.com/class/newtlaws/u2l2b.cfm
Hibbeler RC. Engineering Mechanics: Dynamics, 12th Ed.  Pearson Education, 2010
Hibbeler RC. Engineering Mechanics: Statics, 12th Ed. Pearson Education, 2009
Simmons L. Westside Book of Methods.  Westside Barbell, 2007

Athletes and Powerlifting

The Westside Method. 5/3/1. 5x5. Sheiko. Smolov.  Just to name a few, these are all programs aimed at getting you strong and smashing weight like its no one's business.  For the athletes we all know getting strong puts you at a huge advantage; hence the boom in the Strength and Conditioning field.  Given equal skills the stronger/faster/better conditioned athlete will win.

Pictured: Skill level not being equal

As we delve deeper into the programming of strength for athletes we need to draw a line of what works and what doesn't.  One can draw a conclusion and say "a strong athlete is a good athlete, thus I will make my athlete as strong as possible in the squat, bench and deadlift; and therefore train him like a powerlifter."  However we need to keep in mind the sport specific aspects of our athlete; the way they move and the types of postures and actions in their sport.  Getting strong is great, I'm not arguing that, but the type of strength is even more important.

Differences

So what separates powerlifters and athletes?  At face level, the end goal of their respective sports.  Powerlifters strive to increase their maximal strength in the squat, bench press and deadlift.  They can achieve this by lifting maximal loads (maximal effort), lifting lighter loads at high velocities (dynamic effort) and/or lifting moderate loads for higher volume (repetition effort).  They perform their three main lifts, as well as secondary lifts meant to strengthen muscle groups involved in the main lifts.  In the end, everything they do is meant to improve their squat, bench press and deadlift.

Athletes, on the other hand, have the main goal of improving their sport performance.  If you play baseball your goal is to be able to hit more balls, throw a ball further, run bases faster.  Performing the powerlifts can help; its been scientifically proven that increasing maximal force output has effect on athletic performance in all sports which require high force output.  A lot of sports focus on power output - how fast you can apply a high force.  However, the argument is whether or not training the athlete like a powerlifter is beneficial.  I’ll list a set of pros and cons of powerlifting for athletics.

Pros:

- Powerlifting will improve maximal strength and possibly speed strength (depending on lifting style), which can carry over to athletics.

- Powerlifting can teach intensity, conditioning (GPP) and reinforce certain neural patterns used in sports.

Cons:

- Strength curve: powerlifts decelerate at the end ROM.  In sports you have to accelerate through the entire motion.

- Injury risk.  If you have a million dollar athlete, why risk season/career ending injury when you can improve performance through other means than powerlifting.

- Specificity to sport:  will squat/bench/dead make you a better pitcher, wrestler or basketball player?

To Squat, Or Not To Squat?

Let’s look at the pros.  First - getting strong can carry over to sports.  True, to an extent.  Athletes who rely on maximal strength (ie. offensive linemen, shotputters) can benefit from getting strong by performing the powerlifts.  Getting strong won’t make you a good athlete, but when skill levels are equal the stronger/faster athlete will win.  Going back to the comment I made earlier about a lot of sports being about power output, research comparing force and velocity curves has shown that as maximal force increases, velocity output at lower forces increases.  

Science and Practice of Strength Training: Nonparametric relationship between maximal maximorum force (Fmm) and velocity

From the graph above, as the Fmm increases (your maximal strength), velocity of movement when exerted against forces less than Fmm increases.  In the example from the graph, a 6 kg load is used and lifted with the arm.  The data plotted shows the velocity of the 6 kg weight, as the user's Fmm increases.  Consequently, the higher your maximal force output, the higher your velocity output at lower force levels.  Therefore, if your athlete is strong as hell and can squat 600 lbs they’ll be extremely fast when required to overcome only 300 lbs during a squat; much faster than an athlete who can only squat 400 lbs.

Secondly, look on Youtube and watch these powerlifters train.  What do you see?  Intensity, determination, drive.  Who can’t benefit from that?  By introducing the athlete to a powerlifter’s setting they can be shown higher levels of intensity and learn to push themselves while playing their sport.

 The cons elaborate on the points previously listed.  Getting strong can carry over to sports - true, to an extent.  In research presented by Dr. Vladimir Zatsiorsky, strength definitions can vary depending on the type of athlete you are.  Does a gymnast or freestyle wrestler worry as much about their max squats as offensive linemen should?  The effects of maximal strength (how much weight you can lift overall) vs. relative strength (how much weight you can lift relative to your bodyweight) will play a role depending on the type of sport you play.  Those who play sports involving their bodyweight (ie. gymnastics, wrestling) may benefit more from training with their bodyweight and not with increasing their maximal strength through the powerlifts.

Another big issue comes back to the statement made about athletes having to express high levels of force at high velocities.  For example, when throwing a punch you want as  high a handspeed as possible to apply as much power to your opponent’s face as possible - boxers don’t slow their hands down as they make contact with their opponent; they accelerate through and their hand comes out the back of their opponent’s skull.  For football players as you make a tackle do you slow yourself down?  No, you accelerate through your target to bring them down.  So how does this apply to powerlifting?  Look at the bench press.  Some argue the horizontal pressing helps mimic the range of motion and position as throwing a punch.  However look at the velocity of the bar relative to the range of motion.

Science and Practice of Strength Training: Bar velocity during concentric phase of explosive bench press (dotted line) and explosive bench press throw (solid line)

Notice in the above graph that during a dynamic effort style bench press maximum velocity occurs around midway through the concentric portion, and that as we reach full ROM velocity is decreasing thus acceleration is negative.  For the bench press throw (same bench press motion, but as you reach lockout you throw the bar up in the bar) velocity is steadily increasing even at the end ROM.

If a boxer wants to accelerate his fist through his ROM, performing a bench press where the hand slows down at the end ROM would be a bad idea.  Ideally the boxer wants to connect when his arm is in full extension, not when its still bent halfway.  If we keep training the boxer with the bench press, he eventually grooves the motor pattern to maximize velocity midway through his punch and then decelerate at the very end - bad idea if you want to knock someone out.

Secondary concerns involve injury risk.  I know you’re all thinking “All sports have their risks; its not my fault you’re a huge p***y.”  I understand that but think about this: what if you had an athlete who has the potential to make millions of dollars playing baseball as a pitcher.  He wants to get stronger, and in turn throw a ball faster, so you make him bench press.  However, while one day attempting a 1 rep max he tears his rotator cuff - season is over, career is never the same and there goes millions of bucks down the drain.  What have you done?!  What if you were able to improve the pitcher’s ball velocity by improving his technique; a much safer and effective method.  When it comes to athletes, efficiency is key.  Everything we do has a risk associated with it.  Squat form is off and we herniate a disc.  Throw one too many baseballs and there goes your rotator cuff.  The big thing is knowing when and where to take these risks, and now exposing yourself to any unnecessarily. 

Finally we’ll get into specificity of exercise.  Defined by Dr. Vladimir Zatsiorsky, specificity has to do with how well performing certain tasks carry over to an end goal.  For example, if an athlete were to train his squat in a powerlifter’s fashion, how well would his new maximal strength be applied to being an offensive lineman or the parallel bar event in gymnastics.  In the first event, yes, improved maximal strength can be carried over to driving opposing players back for short bursts of time.  In the second scenario the specificity of max effort squatting for gymnastics is much lower since the gymnast relies moreso on sustained periods of bodyweight strength.  One can argue for the use of the powerlifts during an Accumulation Phase of periodized training but thats a story for another day.

Olympic Lifts?

As an aside, olympic lifts have been considered as a replacement for the powerlifts.  They satisfy the requirements of teaching the athlete how to accelerate through the end range of motion, while providing enough load to improve maximal strength.  Research from the National Strength and Conditioning Association (NSCA) has indicated high levels of power output during the olympic lifts; exactly what athletes strive to accomplish.  However, olympic weightlifters spend literal decades perfecting their technique.  How can we expect a 14 year old football player who can barely walk in a straight line to master such a complex movement in a couple months.  

He spent most of his life training to do this. Can Junior, while balancing football practice, calculus homework and an acne problem?

In theory using the olympic lifts will help, but factors such as the learning curve required make it not as feasible.  Exercises such as jumps, sprints and throws still apply the methods of teaching acceleration but without the complexity of olympic lifts.  If you have a background in olympic weightlifting, however, feel free to incorporate them.

Conclusions

Training the powerlifts can be a very useful tool for anyone who wants to get strong; its applying it to specific sport practices which can cause controversy.  For the athlete getting strong is only one facet of their training; they also must be fast, agile and hold skill in their sport.  The biggest concern with powerlifting for athletics I’ve come across has to do with the velocity vs. ROM observations - as each of the powerlifts shows a marked deceleration as the end ROM approaches it is teaching the athlete to do the opposite of what they are supposed to.  Injury potential is another factor, although this varies from person to person.  For a beginner athlete who would benefit from increased strength, then yes, using a powerlifting style program may help; but for a million dollar athlete who’s livelihood depends on them staying healthy, you may have to reconsider your options.  Specificity to sport also determines how you will train your athlete.  If you play a sport involving mostly bodyweight it may not be so wise to improve your maximal strength.

What might I suggest for athletes looking to get strong for their sports?  The powerlifts are a great building block for general strength, but only if used to accentuate the athlete’s training - not the end all be all.  For the velocity/ROM problem, look at various plyometrics and thrown movements.  Back to the graph posted comparing velocity and ROM of bench press techniques, the bench press throw is much more favourable for developing acceleration than the traditional bench press.  Similarly using a medicine ball, sandbag or kettlebell to throw will illicit the same type of velocity output.  For the lower body, look at various jumps and sprints.  Olympic lifts were mentioned earlier but the complexity of the technique makes it unfeasible for most trainees.  However, look at the lower body extension of the olympic lifts and jumps.  At the peak of each the ankles, knees and hips are in full extension (triple extension).  If olympic lifts cannot be done, jumping and throwing can mimic the explosive triple extension.

Full Extension of the body during a vertical jump

At the end of the day, getting strong will help the athlete, no questions about it.  The way we get them strong becomes the point of debate.  Powerlifting can be one of the ways to get athletes strong, but as an assistance to their sport training.  However, if you have the hand-eye coordination of a drunk chimpanzee no amount of squatting will help you shoot a basket, score a goal or punch someone in the face.

References:

- Spagele T, Kistner A, Gollhofer A.  Modelling, simulation and optimisation of the human vertical jump. J Biomech 1999;32(5):521-430

- Garhammer J. A review of power output studies of olympic and powerlifting: methodology, performance prediction and evaluation tests. J Strength Cond 1993;7(2):76-89 

- Chiu LZF, Schilling BK. A primer on weightlifting: from sport to sports training. J Strength Cond 2005;27(1):42-48

- Izquierdo M et. al. Effects of long-term training specificity on maximal strength and power of the upper and lower extremities in athletes from different sports. J App Phys 2002;87(3):264-271

- Jason Ferrugia.  Death to the Conjugate Method?  Testosterone Nation, 2006.

- Liao CM, Masters RSW. Analogy learning: a means to implicit motor learning. J Sports Sci 2001;19(5):307-319

- Zatsiorsky VM, Kraemer WJ. Science and Practice of Strength Training. Human Kinetics, 2006. p 6-8,18-21, 52-56, 76

Kinematics of Motion, Part II: Angular Movement

Settle in class, today's lesson will build upon the physics we learned in a previous post.  Last time we discussed the merits of multibody dynamics and kinetic links, and how they play a role in human movement.  While that's all well and good we need to get into the basics of how we can analyze our movements.  When we take a step, what are the velocities/acceleration/forces of our foot/shank/thigh?  What are the angular velocities and accelerations and moments of inertia of the moving parts?  Why do we even care?  Well if you want to get strong and fast, or teach others to get strong and fast, you'd better at least know how we move.

These guys might be able to help with this article

That Was Fast

All movements no matter how small or big have an associated velocity and acceleration.  The quick and dirty of it is velocity is the rate of movement - how far you travel in a certain amount of time, given in the units of distance per time (km/h, m/s, miles/h, etc) - where average velocity = d/t.  Acceleration is defined as the rate of velocity - how fast you are moving in a certain time, given in the units of velocity per time (m/s^2, etc) - average acceleration = v/t.

As an example let's say you walk 10 m and it takes you 5 seconds to do so.  Your velocity for the entire 10 m trip (average velocity) is 2 m/s (10m / 5s).  Likewise, let's say you're driving in a car now; currently you're travelling 10 m/s, but you want to go faster so you speed up to 30m/s and it takes you 5 seconds to do so.  Your acceleration during that period is 4 m/s^2 (30-10/5).

This is all well and good but moving in a straight line, like sprinting down a 100 m path or driving down the street; but what about when moving in a circle or along an arc?  This is where angular velocity and angular acceleration come into play.

The general principles still stay the same; the angular velocity is a rate of distance but now the distance in no longer a straight line, but an arc.  We define angular velocity as 'w', where w = 2πf, and f is the frequency of revolution (revolutions per second).  That's all well and good if we know the rotational frequency, but sometimes we don't.  Instead we may be presented with the tangential velocity (v) - a straight line velocity (like what we discussed in the first paragraph) that comes off the arc we are traveling in.  Given the tangential velocity we can still calculate the angular velocity, as long as we have the arc's radius (r); w = v/r.


Angular acceleration works in a very similar matter.  Where straight line acceleration was the rate of velocity, angular acceleration is the rate of angular velocity.  We define angular acceleration α = w/t, or α = a/r; where a is the straight line acceleration. 


Complications


So if that wasn't complicated enough, I'm going to F it up one more notch.  Picture this: you're being drive in a bus traveling at 100 km/h.  You decide to stretch your legs and go for a walk, so you walk forward inside the bus at 2 km/h.  Relative to an observer sitting inside the bus, he sees you moving at 2 km/h.  However, an observer outside of the bus will see you move at 102 km/h.  This is because to the observer on the bus, his world (the bus) is stationary and you are the only object moving.  To the observer outside, his world is the outside environment, and the bus is moving with you inside it, thus your net velocity will be the buses' plus yours.


The same scenario occurs with angular velocity and acceleration too.  Unfortunately, we can't just add/subtract the values from one another and call it a day like with the straight line values, so we have to do some fancy math to figure things out.  This effect is known as the Coriolis Effect; the deflection of an object when moving along a rotating frame of reference.  


Before I lose you, that pretty much means what I said in the sentence before; if you're standing on a merry-go-round rotating clockwise from the top but you walk in a counter clockwise fashion, if the merry-go-round's angular velocity is greater than yours, to an observer watching you from the ground you'll still be moving clockwise.  However, to an observer standing with you on the merry-go-round you're moving counter clockwise?  Why is this?  Coriolis Effect!

Coriolis Effect:  NOT used to determine which way the water drains

I won't get into the calculations and formulas for involving the Coriolis Effect into dynamic force, but when analyzing movements we can now determine the overall velocity output of a multi-body segment provided they are moving independently of each other.  Even in practice engineers/biomechanists don't calculate these effects by hand but rather plug them into a computer; physically calculating this is usually reserved for those with time on their hands, or 2nd year engineering students.  If you fall under one of those two categories you can check it out here.

Pictured: A horribly disproportionate leg

Application

Alright, so why do you need to know this stuff?  Simple - all our movements are governed by laws of Kinematics.  Throwing a ball, sprinting, jumping, etc can all be expressed using the concepts I've outlined above.  

In this house we obey the laws of Thermodynamics!

As outlined in a previous post the human body can be represented by pins (joints) and segments (limbs). Each time a limb moves it is rotating about a pin joint; even with an overall linear motion (ie. a punch) each limb is rotating about its joint and thus has rotational kinematic properties - a direction of rotation, inertial centre of mass, angular velocity and angular acceleration (assuming a dynamic situation).  Therefore, we can state that all human movement can be expressed as angular velocities and moments of inertia of various limb segments.


When you take a step, what is occurring in your lower body?  Your thigh, shank (shin) and foot all rotate and move independently.  More specifically your hip is moving in flexion, so your thigh is rotating in a direction; your knee is moving in extension, so your shank rotates as well; your foot is dorsiflexed in anticipation of the heel strike, so your foot rotates.  When we walk no one walks with all three body sections moving in complete unison unless you wear a pair of super tight jeans and walk like Frankenstein.


All of the limb rotations and movements are not in sync with each other; the hip flexes initially, then the knee extends some short time after, then finally before the foot strikes the ground the foot dorsiflexes to allow heel strike.  Hence they will have their own relative angular velocities and accelerations, relative to an observer sitting on their surfaces.  


Just like with the bus example, to an observer standing back and watching you walk, there will be an absolutely angular velocity and acceleration of your foot.  That's where the Coriolis Effect calculations will come in; people who may use this include soccer analysts, examining a striker's foot prior to ball contact or a running coach looking at foot placement and movement.


For sport specific application, the actual velocities of each limb segment play a large role.  For the sprinter high hip flexion power is needed to drive off fast.  Therefore, the thigh will be moving with an extremely high angular velocity and acceleration, absolutely and relative to the shank.  Taking this one step further, what muscles are required to create high hip flexion forces?  Knowing this we can suggest exercises for the sprinter to perform.  We can apply this practice to all portions of sprinting gait to optimize the sprinter's performance.  The same goes for analyzing a soccer kick, baseball pitcher's throw or any other movement where limb segments are moving independent of one another.


Conclusion

Thus ends your physics lesson for the day.  The take home point is that in real life movement limb segments will move independently of each other.  No one walks like Kramer in tight jeans, or swings their arms like Raquel Welch.  So when we take this into consideration we need to apply principles of Coriolis Effect into our analysis when determining output velocites/accelerations.  This becomes useful for those analyzing movements such as walking, running, sprinting, throwing a ball, kicking a ball, etc. In later physics related posts I'll get into subjects such as static vs. dynamic force scenarios, power output and in depth sport specific applications.



References:

http://hyperphysics.phy-astr.gsu.edu/hbase/rotq.html

Hibbeler RC. Engineering Mechanics: Dynamics. Pearson Prentice Hall, 2010

Kadaba MP, Ramakrishnan HK, Wootten ME. Measurement of lower extremity kinematics during walking, J Orth Res 1990;8(3):383-392

Cavagna GA, Komarek L, Mazzoleni S. The mechanics of sprint running. J Phys 1971;217:709-721

Young M. Maximal Velocity Sprint Mechanics, United States Military Academy, Human Performance Consulting

How To Make Life Suck A Little Less Each Day

Let's face it:  life can suck.  Not everyone can wake up in the morning feeling like P. Diddy, nor can we brush our teeth with a bottle of Jack despite what the music industry tells us.  Identity theft and oral hygiene issues aside we instead wake up way too early, low back tight, knees creaking walking to the kitchen, getting ready for a day of mind numbing work followed by an awful training session due to fatigue and having your soul sucked out of you.

Why must you turn my office into a house of lies

But this post isn't here to remind you of how awful your life is (your too small apartment, shitty car and awful haircut will do that for you); instead I'm here to help.  Today we will be discussing little tips which can help your life suck a little bit less.

Fish Oil

By now everyone and their grandmother has heard about the benefits of fish oil - improved brain function, improved mood, decreased joint inflammation, decreased LDL levels and a host of other benefits.  Researchers have shown fish oil supplementation to increase resting metabolic rates and decrease in body inflammation.  Other research has shown links between fish oil supplementation and improved lipid profiles, anti-depressant effects and mental health.  Bottom line, you want to get healthy?  Take your fish oil.  If you aren't taking your fish oil then I only have one question for you:  what the hell is wrong with you and get off my website.

A magic little pill that'll make you feel great, and you don't have to smuggle anything over the border

Dosages vary depending on who you ask.  The side of the bottle tells you to take 1 capsule (1 gram) per day.  The problem I have with that is usually these recommendations on the side of the bottle are meant for the average person, and in all honestly the average person is weak, stupid and out of shape.  Unless you're an underachieving sloth as well I'd rather listen to someone who has experience with success.  Those such as Dr. John Berardi, Dr. Mauro Di Pasquale and Coach Charles Poliquin have suggested higher doses; their specific dosing schemes can be found on their respective websites (listed on the right).  I've noticed marked improvements in skin quality when I regularly use higher dose of fish oil (15-20 grams), and decreased joint pain/increased mobility.

A Proper Warmup

So you're ready to tear it up in the gym.  You get there but something doesn't feel quite right - you feel a bit slow and sluggish, knees and hips creak as you take your first set on squats, hitting depth kinda hurts, you have no pop out of the hole.  Each progressive set feels heavier and makes your joints scream.  "Maybe I should take it slow today" but instead you jack up the weight.  Your final set involves the gym attendant calling the ambulance for you.

So what happened?  You were sluggish, couldn't find your groove and your joints hurt.  Sounds like someone didn't warm up properly.  Most serious lifters know the merits of a good warmup.  You can't smash serious weights without your body running like a well oiled machine.  A good warmup will help you accomplish a few things - increase body temperature, improve tissue quality before lifting, bring heart rate to a steady state during work, increase oxygen uptake and groove the proper motor patterns for lifting - just to name a few.  Qualitatively I feel a huge difference when I get in a solid warmup including light cardio (skipping rope or sled dragging), soft tissue work, dynamic and static stretching, mobility drills and activation work.  Days I don't do that my lifts feel heavy, I can't find a good lifting groove and my joints hurt the whole session.  Days I do get that in I feel like a million bucks, everything is going my way and I'm ready to go set after set.  As for warmup sets, I take a page out of Dave Tate's book; he's mentioned in past articles that at the famed Westside Barbell gym, they may do multiple sets with just an empty bar if they don't feel the right groove on their lift.  And if it's good enough for Westside it should be good enough for you.  Too many guys you see at commercial gyms will be 'platers' (another Dave Tate term), meaning they'll put on one plate (135 lbs), put on another plate 225 lbs) and so forth.  The problem is if your max is 185 lbs are you really going to jump up to 73% of your max (135 lbs) on your first set?  You will if you're a dumbass.

You are not better than him

Now there's scientific proof to back up what I'm saying; a study from the Journal of Strength and Conditioning Research has shown marked differences in oxygen uptake, heart rate during work and lactate pH when comparing active warmups (mobility work, activation work), passive warmups (general things to raise your body's temperature) and no warmup.  The group that performed an active warmup prior to activity found increased oxygen uptake and decreased heart rate during work.  Long story short, those who perform an active warmup had greater metabolic efficiency.

Lifting in the Morning

How many of you like to train first thing in the morning?  How many of you squat and deadlift appreciable loads while training in the morning?  How many of you complain of low back pain or herniated discs after squatting and deadlifting first thing in the morning?

Rise and shine

Spinal disc injuries are the bane of my existence.  Right up there with ruptured tendons they are my most  hated injury and I've already bulged my T12-L1 in January 2009 which has left a permanent mark on my physical performance.  For those of you performing low back-taxing lifts early in the morning you may want to think twice after hearing this.

Research from Dr. Stuart McGill has shown the spinal discs to be more susceptible to injury early in the morning than at any other time of day.  As you lay down when you sleep, osmotic pressures (pressure from the inward flow of fluids) cause your spinal discs to fill with fluid and overhydrate - this is one reason you are taller in the mornings than at night.  Throughout the day as you are upright that compressive effect from gravity is able to help drain the discs of excess fluid.  During this morning period overhydration the discs have been proven to be more susceptible to herniation and endplate fracture; any excess compressive/shear/torsional loads will damage the spinal discs more readily, and the ability for the discs to absorb said loads is decreased when overhydrated; disc bending stresses have been shown to increase by 300% and ligament stresses increase by 80% during this time.  Do yourself a favour and wait at least an hour after waking before attempting major lifts involving the low back, and be sure to warm up thoroughly (just like what I said a few paragraphs above).

Foam Rolling

You're in the gym and start to perform a couple bodyweight movements to get some blood moving but notice your range of motion sucks.  You want to perform some bodyweight squats but as you bend your legs you feel a noticeable pull and the front of your knee hurts.  Welcome to the world of referred pain and scar tissue adhesion.

As our bodies take damage from the outside world (lifting weights, falling off a ladder, getting your ass kicked by a troup of boy scouts), our natural protective mechanism takes over - thick inelastic adhesions form over muscles and fascia.  Unfortunately these adhesions can limit muscle elasticity, trap nerves causing referred pain and diminish blood flow.  Luckily we have many tools at our disposal to get rid of these adhesions.  We could shell out our hard earned money and see a specialist to poke and prod you (myofascial release) for an hour, or we could save our cash and do it ourselves via a foam roller.

Who thought a long rod could give so much pleasure

A foam roller is just a tool for self myofascial release, but we can use anything depending on the size of the muscle group, from a lacrosse ball to a PVC pipe - anything with enough rigidity to be effective but not rigid enough to bruise (unless you like that sort of stuff, I don't judge).  I won't get into foam rolling technique, but Eric Cressey and Mike Robertson wrote an excellent article a while ago on the subject right here.  The way I do it is I lay on my foam roller/lacrosse ball/whatever, and roll around til I find something that hurts.  Once I land on a painful area I'll apply constant pressure for 30 seconds or so, then roll along the direction of the muscle fibres.  The difference in tissue quality is night and day.  I can barely do a bodyweight squat without feeling the tightness in my quadriceps pulling on my patella and tightness in my hips.  After foam rolling my IT band, quadriceps, adductors and piriformis I can descend into my squat relatively pain free.  You could spring for a real foam roller, but with the rise in popularity over the past few years they've gone up all the way to over $50.  A generic white coloured one I purchased from an unnamed Canadian fitness supply store lost its rigidity after 6 months of use.  Some people shell out the cash for a good one but if you're on a tight budget head to your local hardware store and buy a lenth of PVC pipe.  You can wrap it in athletic tape to prevent slipping and if its too hard, wrap it in a thin mat.

Conclusions

Hopefully after reading all that you'll pick up some tips on how to get through your day with a bit more energy, a bit less injuries and aches and a few more PR's.  Feeling like crap?  Take your fish oil, warm up adequately, remember to foam roll and don't do your 5 second eccentric romanian deadlifts right after you wake up (the idiocy of 5 second eccentric romanian deadlifts will be discussed in a later article).  Remember, I'm on your side.


References:

P J Nestel, W E Connor, M F Reardon, S Connor, S Wong, and R Boston. Suppression by diets rich in fish oil of very low density lipoprotein production in man. J Clin Invest. 1984 July; 74(1): 82–89


van der Tempel H, Tulleken JE, Limburg PC, Muskiet FA, van Rijswijk MH. Effects of fish oil supplementation in rheumatoid arthritis. Ann Rheum Dis 1990;49:76-80

Sinn N, Bryan J. Effect of Supplementation with Polyunsaturated Fatty Acids and Micronutrients on Learning and Behavior Problems Associated with Child ADHD. J Developmental & Behavioral Pediatrics 2007;28(2):82-91

Peet M, Horrobin DF. A Dose-Ranging Study of the Effects of Ethyl-Eicosapentaenoate in Patients With Ongoing Depression Despite Apparently Adequate Treatment With Standard Drugs. Arch Gen Psychiatry. 2002;59:913-919.


McGill SM. Low back disorders: Evidence-based prevention and rehabilitation, Human Kinetics, 2007, p96


Adams MA, Dolan P, Hutton WC. Diurnal variations in the stresses on the lumbar spine. Spine (Phila Pa 1976). 1987 Mar;12(2):130-7.


Brunner-Ziegler S, Strasser B, Haber P. Comparison of Metabolic and Biomechanic Responses to Active vs. Passive Warm-up Procedures Before Physical Exercise. J Strength Cond Res. 2010 Aug 20

Gossman MR, Sahrmann SA, Rose SJ. Review of length-associated changes in muscle. Experimental evidence and clinical implications. Phys Ther. 1982 Dec;62(12):1799-808