Wednesday, January 18, 2012

The Best Power Clean?

Comfort, P., Allen, M., & Graham-Smith, P., (2011). Kinetic Comparisons During Variations of the Power Clean. Journal of Strength & Conditioning Research, Volume 25 (number 12) 3269-3273.

This article in the most recent NSCA journal discusses two basic variants of the power clean exercise. The clean is an excellent exercise for training power production of the lower body. It's already assumed that the power version is preferable for sports training for it's specificity. This study examines the differences between starting positions: on the ground, the hang position and mid-thigh. The study also compares the clean pull from mid-thigh.

The study found that the mid-thigh start position produced the highest force (ground reaction force (GRF)), highest rate of force production (RFD) and highest power (P). The clean and pull produced similar forces. For the purposes of sports training, and especially the incredibly quick movements of combat, these characteristics are some of the most important.

That the force characteristics are highest for the mid-thigh start is not surprising given the mechanics. Regardless of the start position the bar has to be brought to the same end position. Producing sufficient force for this with a smaller movement requires the acceleration to be higher. And so RFD and Power are higher.

The conclusion is that, for sports and combat training, the mid-thigh start position best suits the the strength objectives.

Thursday, January 12, 2012

Types of Strength Training

Different intensities or loads of strength training will produce different results. This is an essential principle in strength training. The selection of load for an exercise then needs to be based on the training objective. Strength training can improve muscular endurance, size of the muscle, called hypertrophy, max (or basic) strength and power.

Power is differentiated from strength by the speed of action; the term power is used to refer to high-speed strength. In physics terms power is equal to Force times velocity, so faster application of force equals higher power. In combat sports and swordplay power is most often our objective.

Each of these can and should be trained as part of a comprehensive training regimen. How to incorporate them all is part of a periodization scheme - a topic to be covered later.

Note that any strength training will improve all four capacities: endurance, size, strength and power. However, a given load will develop a particular characteristic more than others.

The primary variable in the periodization of strength training is the weight being lifted and the number of times that weight can be lifted. This will generally be described with the concept of Repetition Maximum (RM). RM is the max weight that can be lifted a given number of times. So a 10 RM weight is one that I can lift 10 times and then I need to stop. A 1RM weight is on that I can lift only once and then I need a break.

For each exercise different weights will be necessary to produce different RM's. There are resources for estimating these, but most folks can just as easily figure it out by trial and error. Start low and work upwards in small increments until the objective is reached.

Muscular Endurance
Loads of 12RM to 20RM or more will mostly produce gains in endurance, not maximum strength. Of note is the fact that endurance is achieved with different muscle cells than strength so the gains in strength will be minimal. Endurance training will also produce a modest increase in size of the muscle but this is not the optimal load for that objective.

Hypertrophy
Hypertrophy is the increase in size of a muscle that comes with training. It is primarily the result of the body building more muscle fibers at the molecular scale. The body will also adapt by increasing the blood vessels in the muscle. Hypertrophy is achieved at all levels of strength training but is optimally achieved with 8-15RM loads. The goal of the hypertrophy phase is to produce more muscle tissue to be used in the other phases of training. Loads of 6RM to 12RM will also increase muscular endurance. For swordfighters the amount of muscular endurance needed is not great and so this range of loads will usually be sufficient for endurance training.

The force that an individual muscle fiber can produce is based entirely on it's cross-sectional area. So hypertrophy is a necessary part of achieving maximum strength. Higher loads will further train the coordination of separate muscle fibers, so that the fibers work together better.

Low-Speed Strength
Loads in the 1RM to 6RM range will produce gains in maximum strength primarily by training the neuromuscular aspects to use the muscles more efficiently. Maximum strength increases maximum speed of action because strength refers, in physics terms, to Force. Force is mass times acceleration, so increases in force production are increases in the ability to accelerate. Therefore increases in strength will increase the speed with which an attack can be executed. Max strength training provides a foundation on which high-speed strength can be added.

Hypertrophy will continue to occur at these loads but to a lesser degree. There will be little increase in muscular endurance but endurance gained in earlier phases will be maintained. However, endurance will be increased secondarily. The weight of your hand or foot or sword does not increase so as max strength increase the percentage of strength necessary to hold it up or move it decreases. 


Power - High-Speed Strength
Power is well trained by high loads in the 1RM to 5RM range. Additionally, training at higher speeds will develop power. There are several ways to incorporate such into your training. In the weight room you can move the weights at higher speed. Instead of pushing the weight up over a 1 or 2 count, you can explosively lift the weight as fast as you can. When moving the weight faster you should expect to get fewer reps out of each set. So a 8RM weight will become a 5RM load when done explosively.

Other options include Olympic lifts, squat jumps, bench press throws, chains and resistance bands etc. All of these are topics for future posts. But don't forget that high weight loads will still do much to increase power. These more complex methods are not necessary for power development - they are used to refine a strong athlete to maximum potential.

References 
Baechle, T.R. & Earle, R.W. (Eds.). (2008).  Essentials of Strength Training and Conditioning (3rd ed.) . Human Kinetics. Champaign, IL

Wednesday, January 11, 2012

Increasing the Impact Force of the Rear Hand Punch - Part 2

Rear Leg Drive was covered in the previous post. This post will deal with the other 4 concepts from that article.

* * *

Turner, A., Baker, E., Miller, S.,  (2011). Increasing the Impact Force of the Rear Hand Punch. Strength and Conditioning Journal, volume 33 (number 6), pages 2-9.

The article discusses the kinetics and kinematics of the rear hand punch to show ways of increasing the impact of the punch. Turner indicates that the material is generalizable to other strikes, which I don't doubt. The rear hand punch is used as the basis of the analysis because it is well understood, used in many arts and the most powerful punch.

Five key aspects of the punch are identified to optimize the strike:
1. Rear leg drive
2. Landing with a rigid front leg
3. Stretch-shortening cycle of the trunk
4. Velocity of the strike
5. Effective mass of the strike

These key aspects align with the key elements of the kinetics of the strike
Rear Leg Drive - the rear leg is used to initiate the strike and extended explosively to contribute power. This is done with the front leg in the air and moving forward. The more powerful the rear leg drive the harder the strike.
Rigid Front Leg - the front leg must land rigidly to provide a brake on the forward motion of the body. This focuses the rear leg drive on the upper body. The more rigid the braking action, the more force is transferred to the strike.
SSC of the Trunk - the rear shoulder is pulled back early in the strike coiling the trunk to generate more power. This occurs because of the elastic nature of musculature. Stretch Shortening Cycle (SSC) is the neurologic component that increases the elastic reaction of the muscles. A better trained SSC in the trunk increases the trunks contribution to power.
Velocity of the Strike - the arm can move at tremendous speed and is quite light, so it's primary contribution to force is through velocity. The faster the arm moves the harder the strike.
Increase Effect Mass - the arm actually slows down just before the strike lands. Activation of the muscles in the arm to make it rigid cause this effect. A rigid arm allows more of the mass of the body to be contributed to the power of the strike.


Rigid Front Leg
Landing with a rigid front leg will cause more force to be transferred to the strike. Substantial bend in the knee is the most likely indicator that the front leg is not rigid enough. Training for a more rigid leg should be done gradually, because we are training to overcome the body's natural defense against impact/landing. As long as this process is done gradually then the connective tissues and related structures will strengthen appropriately.

Training for a more rigid landing can be done with box drops. Simply step off a plyometric box (or similar) and land. Don't focus on trying to land rigidly, let that develop at it's own pace. Start with small boxes and work your way up to taller boxes, as well as single-leg drops. When incorporating this with other plyometric programs it is important to take into consideration the total number of contacts per training session, so as not to overload the tissues.

Olympic lifts and squat jumps will also help develop this characteristic.

Stretch Shortening Cycle of the Trunk
The rear hand punch, and many other strikes, include a wind-up action that brings the elastic nature of the muscles into play. This elasticity is the reason that untrained folks will naturally pull their fist back before punching. It's also the reason why when you jump you naturally drop down just a bit before moving upwards.

The elasticity of the musculature is the result of two factors: connective tissue is elastic similar to the way that rubber bands are; and our nervous system has controls on the muscles that produce a similar effect - which is known as the Stretch Shortening Cycle (SSC). These two together can substantially add to force production.

Medicine ball exercises can be used to train this capacity. The most basic is a side pass.
  1. Stand in your typical striking stance with your left foot forward. 
  2. Hold a medicine ball at arm's length with both arms. 
  3. Rotate clockwise a short distance, quickly and then reverse direction and throw the ball. 
  4. If possible catch the ball and repeat, making sure to counter turn a little with each catch or before each throw.
  • Focus doing the throw with the torso, not the arms.
  • For this exercise, we are concerned with rapid action so a light ball of around 2 kg is sufficient. 
  • Not all med balls are equal, some bounce better than others. For fighter training I think the bouncier kind are more useful for a wide variety of drills.
A forward and backward pass can be done as well, following the same principles. For the forward pass face the wall with your feet squared and the ball over head. Arch back just a little bit before throwing forward. The backward version is done while facing away from the wall and you crunch forward just a bit before throwing overhead and backwards.

There are plenty of good variations on these exercises. This is meant as a good start.

Increase the Velocity of the Punch
Training to increase arm velocity will focus on ballistic type exercises. The focus is on speed not just weight. Here again, medicine ball exercises will help. A variety of throws using form similar to strikes will work for this kind of training. Again, use a light medicine ball to focus on velocity of action. However, the simplest ballistic upper body exercise is the clap push-up.

Another option is to use resistance bands for conventional weight training exercises (not discussed in the article). These increase resistance progressively and so the action starts off fast with a light resistance and the load increases as velocity decreases. This method also plays well into the next concept.

Increase the Effective Mass
The effective mass of the hit is determined by how rigidly linked the parts of the arm and body are at impact. The more rigid they are at impact the more weight is behind the punch. Studies of muscle activation in punches show a double-peak effect. As the hand starts to move forward the muscles activate strongly. Then the relax and the hand sort of glides forward. Last the muscles activate again making the arm and wrist rigid.

This double peak is not observed in shadow-boxing or other training done "in the air". So training with a solid striking target is necessary to train the body to transfer force on impact. Pad and bag work is the basic way to do this. For weapon arts it's necessary to have a striking target like a pell to hit.

* * *
The article also has a sample program to show the combination of these various training elements. That's a whole other topic though, and I'll get into it with later posts.

Saturday, January 7, 2012

Increasing the Impact Force of the Rear Hand Punch

The Strength and Conditioning Journal, published by the NSCA, did a special issue all about Combat Sports. I'm gonna review most of the articles from that issue.

* * *

Turner, A., Baker, E., Miller, S.,  (2011). Increasing the Impact Force of the Rear Hand Punch. Strength and Conditioning Journal, volume 33 (number 6), pages 2-9.

The article discusses the kinetics and kinematics of the rear hand punch to show ways of increasing the impact of the punch. Turner indicates that the material is generalizable to other strikes, which I don't doubt. The rear hand punch is used as the basis of the analysis because it is well understood, used in many arts and the most powerful punch.

Five key aspects of the punch are identified to optimize the strike:
1. Rear leg drive
2. Landing with a rigid front leg
3. Stretch-shortening cycle of the trunk
4. Velocity of the strike
5. Effective mass of the strike

These key aspects align with the key elements of the kinetics of the strike
Rear Leg Drive - the rear leg is used to initiate the strike and extended explosively to contribute power. This is done with the front leg in the air and moving forward. The more powerful the rear leg drive the harder the strike.
Rigid Front Leg - the front leg must land rigidly to provide a brake on the forward motion of the body. This focuses the rear leg drive on the upper body. The more rigid the braking action, the more force is transferred to the strike.
SSC of the Trunk - the rear shoulder is pulled back early in the strike coiling the trunk to generate more power. This occurs because of the elastic nature of musculature. Stretch Shortening Cycle (SSC) is the neurologic component that increases the elastic reaction of the muscles. A better trained SSC in the trunk increases the trunks contribution to power.
Velocity of the Strike - the arm can move at tremendous speed and is quite light, so it's primary contribution to force is through velocity. The faster the arm moves the harder the strike.
Increase Effect Mass - the arm actually slows down just before the strike lands. Activation of the muscles in the arm to make it rigid cause this effect. A rigid arm allows more of the mass of the body to be contributed to the power of the strike.

Rear leg drive
Rear leg drive is best increased by exercises that make use of the full extension of the legs. Basic weightlifting exercises for this are the squat and deadlift. Specifically, the traditional bent-leg deadlift should be used for this objective since it includes knee extension as well as the hip extension. Calf raises, especially one-legged calf raises, are a good assistance exercise (not mentioned in the article), since ankle extension (plantarflexion) is not included in the squat and deadlift. The single-leg version is preferable from the viewpoint of specificity to the sport - you never produce rear leg drive with both legs simultaneously.

Similarly, single-leg variants of the squat and deadlift are also useful. However, single-leg versions will reduce max weight, so they should not be the sole version used. Both max weight lifts and more functional/specific lifts together will contribute to maximal performance.

These lifts are best trained at high loads in the 1-8 Rep Max (RM) range. This range will produce the biggest gains in power generation and peak force. Additionally, these high load lifts produce gains primarily through neurologic training not hypertrophy, so athletes who need to make weight are better served in this type of exercise.

Conventional lifts like these will increase peak force or the height of the Force-Time curve. The strike happens very quickly, around 300 milliseconds. Therefore the rate of force development (RFD) is also important i.e. the steepness of the Force-Time curve. Increasing RFD can be trained with very rapid exercises instead of high loads.

Olympic lifts, such as the Clean, are an ideal method of developing rapid force production. However, they are technically demanding and so require training. Squat jumps, with dumbbells in hand to increase load, are a good alternative to these lifts. Squat jumps are less demanding technically and less physically demanding on the back of the athlete.

Plyometric exercises, such as box jumps, are another good method of increasing RFD. Since strikes are normally executed from a fairly stable position, and because the same strike is not normally rapidly repeated, a quick rebound action is not as necessary for lower-body plyometrics. So jumps for height and distance are effective instead of rapid jumps in succession.

The authors note an important part in training lower body power: long, slow, distance running is counter-productive. Long endurance activities shift muscle from peak power type to endurance type, which is not useful in our sports. The legs seldom fatigue in sword arts and combat sports, but peak power generation is a must.

* * *

This article is a big one, so the review of it will be broken up over several posts.

A Response to Ralf LeBigod

Over on the Armour Archive a link was posted to a presentation done by Ralf LeBigod (his SCA name) on  physical conditioning for the SCA.

Ralf presents some good material in this. But ultimately there is a lot of untrue material that I wish to address.

1. First, he trots out the tired old myth of strength training causing shortened muscles/tendons. This is only true with poorly designed programs. Of the kind that bodybuilding has a reputation for doing. A well-designed program will not shorten muscles/tendons. I'll explain the two common errors and how to design a program that prevents them.

Incomplete Range of Motion
Exercising with an incomplete range of motion (ROM), at high volume, without stretching or activities that use the complete ROM will shorten the tendon. The example of this I've seen in person was a friend who couldn't completely straighten his arm at the elbow. He'd done a huge amount of bicep curls without going all the way down on the exercise. I see this error at the gym today in bodybuilder types.

The solution is simple: use complete range of motion. It's not necessary for every single action/exercise to use the complete ROM. But using the full ROM should be the norm i.e. what you do with almost all exercises. The thing is that if you fully straighten your arm 12 times per set, 3 sets per workout, 3 days per week you can't help but have full ROM at the elbow. Doing that meets the ACSM stretching standards.

Imbalanced Muscles
Front to back, left to right or interal/external rotation imbalances can also lead to shorten tendons. The classic example of this is the bodybuilder who focuses too much on the "mirror muscles", that is the chest muscles. If the chest muscles are too much stronger than the back muscles then the joints will be pulled forwards toward the chest under normal resting conditions. This leads to a slouched or forward rolled shoulder look. The tendons of the chest muscles will then shorten because the resting length is shortened. Correspondingly, the back muscles will lengthen and weaken.

The solution here is equally simple: match each exercise with it's opposite. For every push, a pull. For every flexion, an extension etc. If a muscle and it's opposite (antagonist) are kept near each other in strength then this problem won't occur.

Tendon shortening is not the inevitable result of strength training and is easily prevented.


2. The topic on which he spends the most time is cardiovascular conditioning and here, again, he presents a view based on an old myth. This myth is the idea of needing to use a large amount of long slow jogs/runs for building an "aerobic base". The aerobic base is a prerequisite for interval training in his version and will also mean that a  fighter burns fat instead of carbs while recovering. The idea of building an aerobic base was the result of team sports coaches asking track coaches how to train running. But research in the last 20 years has shown this to be a non-optimal method.

Aerobic capacity is usually measured by VO2max. While long, slow, distance running (LSD) will increase VO2max, it's not the only way. Importantly, interval training methods will also increase VO2max, and are just as effective. So there is simply no need to require three (!) months of 90 minutes a day, or 10+ hours a week, of running just to increase VO2max.

In fact, LSD for increasing aerobic capacity runs into a specificity problem. Our body will not simultaneously develop both high aerobic capacity and high anaerobic power. So three months of training, 10 hours a week for aerobic capacity pulls resources away from power development and anaerobic capacity (1). The interval training that follows development of this "aerobic base" mostly regains the body's ability to work anaerobically after detraining that capacity for three months. And fighters really want to detrain power?

You are much better off starting with interval training. Start with intervals that are relatively easy, like 10-minute jogs, if you are deconditioned, and gradually move up to runs and sprints. Interval training is well-demonstrated as being effective for increasing VO2max. And a wide variety of interval training protocols including fartlek high-intensity and mixed effort protocols will work.

Increased VO2max will produce the recovery benefit that is Ralf's objective. A high VO2max is strongly correlated to good scores of performance decrement (Pdec) on repeated sprint and repeated effort tests. Da Silve (2) et al is a good example of this. Performance decrement is how much an athletes sprint time goes up when they do sprints with short rest periods in-between. Pdec is the best lab measure of "recovery" - that is the ability to go at max intensity over and over again with little rest. Which is, of course, what's required in a fight.

Furthermore, Ralf describes how LSD will increase the percentage of calories that are obtained from fat while engaging in exercise, and describes this as an objective of LSD program. The idea being that if the fat burning system is well trained then a fighter will burn fat in a fight and therefore use "better" recovery energy sources.

First of all, I have no idea why he believes that fat is a better source of energy during a fight. I think his reason is that we store many more calories of energy as fat, so it's a better source than glycogen. However, we are built to use glycogen as a short term energy source for our muscles. And we store thousands of calories as glycogen. Marathoners usually run out of glycogen around the 20 mile point. Far more energy burned than even a war event in the SCA.

Secondly, we can't use fat for energy during fighting. High intensity exercise inhibits the ability to use fat for energy (3). Which makes sense fundamentally. Converting fat to energy is a slow process that can't be done at a high volume, so it can't possibly be used to provide the high-intensity bursts of energy needed for fighting.

Just do interval training for combat sports like the SCA. It works. It works well. And it doesn't waste your time.


Bibliography
1. Baechle, T.R. & Earle, R.W. (Eds.). (2008).  Essentials of Strength Training and Conditioning (3rd ed.) . Human Kinetics
2. da Silva, Juliano F; Guglielmo, Luiz G A; Bishop, David (2010). Relationship Between Different Measures of Aerobic Fitness and Repeated-Sprint Ability in Elite Soccer Players. Journal of Strength and Conditioning Research. Vol. 24, issue 8, pp. 2115-2121
3. Van Loon, L.J., Greenhaff, P.L., Constantin-Teododiu, D., Saris, W.H., Wagenmakers, A.J., The Effects of Increasing Exercise Intensity of Muscle Fuel Utilisation in Humans (2001). Journal of Physiology 588: 4289-4302