The WeighTrainer
The Weakest Link: Strengthening The Tendons And Ligaments
Tendon and ligament training doesn't really appeal to a lot of people. I, myself, was once one of those people. I thought that "it's the muscle that does the lifting so why should I concern myself with the tendon?" And if you don't know some of the more intricate details behind tendon and ligament structure that seems like a very sensible argument (if you'd really like to learn more about the physiological makeup and mechanical properties of tendons and ligaments take a look at this article by Scott J. Hollister, PhD Associate Professor of Biomedical Engineering, Surgery, and Mechanical Engineering and Applied Mechanics, University of Michigan - it may help you follow the rest of this article).
Before you go dismissing the importance of connective tissue (i.e. tendons and ligaments) training consider this: Tendons are subject to mechanical deformation - and they directly transfer energy from muscle to bone, so the amount of deformation they experience directly influences how efficiently force will be transmitted. The more 'rigid' tendons are the less force will be dissipated during the transmission. That clearly tells us that it would be nice if we could somehow make our tendons more 'rigid'.
Repeating myself, tendons simply connect muscle to bone (ligaments connect bone to bone - securing joints). Therefore, anytime a muscle contracts it automatically places a load on the tendon. When a load is suddenly applied to the tendon, proprioceptive receptors in the tendon (namely the golgi tendon organs) are stretched. As a safety response to this sudden stretch the golgi tendon organs signal the nervous system to halt any further contraction of the prime movers of the movement. In simple terms that means you can't lift the weight. Ever shake uncontrollably when hitting the sticking point in a one rep max? Well, there's a good chance that the golgi tendon organs were at work there. As you can no doubt appreciate, if we could make our tendons more 'rigid' they would not stretch as much under a certain load and, therefore, the golgi tendon organs wouldn't 'shut down' the contraction. We can also train our golgi tendon organs/central nervous system to more readily 'accept' this sudden stretch, thereby changing the threshold at which they cause the contraction to be inhibited.
So, as you can see, tendon training can have a profound effect on your ability to lift heavy weights. If you're a strength and power athlete there is no need to state the importance of that.
The Training
As was stated above, when subjected to sudden heavy loading the tendons deform (stretch) quickly, causing the proprioceptive receptors to signal a state of sudden stretch. It is this condition that is also the stimulus for the reformation of the collagen matrix inside the tendons, resulting in increased fibroblast number, and making them more resistant to deformation. So tendon strengthening can be achieved - the key is quickly applying a heavy load to the tendon. Incidently, this is the exact same form of training that can extend the golgi tendon organ threshold. There are three accepted ways of approaching the task:
NOTE: To make this article easier to both read and write, the following arguments are aimed specifically at tendon strengthening and golgi tendon organ threshold/nervous system reprograming. Please understand that, because of their role in supporting joint stability, the following methods also serve to strengthen the ligaments.
Plyometrics
'Plyometrics', in the true American sense (technically 'pliometric' means the lengthening of a muscle - a negative) refers to any rapid reversal of contraction from eccentric (the lowering phase) to concentric (the lifting phase). This is a sub-category of what is often referred to as explosive training (though it is quite possible that an explosive contraction can start from a complete stop with no previous eccentric phase). Westside Barbell-style speed days would, therefore, fall under this category - as would the transition from Squat Clean to Front Squat in the Clean (if it's done properly), or the dip to drive in the Jerk. People have misconstrued the term 'plyometric' to mean that the muscle must necessarily be in a stretched position before the contraction - it doesn't. I think it's because people wrongly confuse muscle stretch with tendon stretch. This simply is not accurate. The stretch state of the tendon in weight training has little to do with the stretch state of the muscle. Tendons stretch simply because they are subjected to loading - the only way that the stretch state of the muscle affects tendon stretch is if the elongation of the muscle affects its ability to exert force (which it does, and that will be considered later).
As an example of how to perform a plyometric I'll use the Bench Press: Take the bar off the rack and allow it to fall somewhat rapidly (but under full control) as soon as it gets to the point where it touches your chest explode it upwards very quickly. The whole rep shouldn't take much more than a second. Obviously, I have left a lot of the details of a power-style Bench Press out but the plyometric technique should be clear.
Remember above when I mentioned that the only way that the elongation state of the muscle affects the amount of load placed on the tendon is if it affects the muscles ability to exert force? Well, as you'll know from the series The Neuromuscular System on the 'Physiology Related Articles' page, this is definitely the case. Borrowing a section:
Particularly relevant to muscle building is the fact that each muscle fiber has a ideal length at which it generates maximum force when contracting. The force generated is directly influenced by the amount of elogation (contraction or extension) that the fiber is under at the start of the contraction. Going back to the sliding filament theory, this optimum length is the point at which the actin & myosin filaments line up in such a way that allows maximum cross-bridge formation. When the muscle is extended more than this the actin filaments cannot make contact with as many myosin cross-bridges - they have slid past each other, so to speak. When the muscle is contracted to a shorter length than opimal, less force can be developed for a few reasons. For one, the normal chemical processes taking place within the fiber become altered so that fewer actin cross-bridge attachment sites are uncovered and available for cross-bridging (the reason this happens is unknown at present). In addition, filaments from the opposite ends of the sacromere overlap and cover some actin cross-bridge attachment sites, further reducing the number of possible cross-bridges. Still further, the myosin filaments come up against the ends of each individual sacromere (what's referred to as the z-lines), impeding any further shortening.
So what is a muscle's optimum length for generating force? Well, generally, it is the length of the muscle while in its relaxed state. How much strength is lost when the muscle contracts at some other length than optimum? Well, at the extreme points of a muscle's extension or contraction (extended ~30% longer and contracted ~30% shorter than optimal) a muscle has the ability to contract only ~50% as forcefully as it can at the optimal length. Keep in mind, though, that you may still demonstrate more strength in these positions (usually in the contracted position) than at the position of optimal muscular force because of mechanical factors such as leverage. The muscle itself, however, will be contracting with less force.
So, in the case of the Bench Press, the muscle has the ability to contract harder at a point roughly halfway through the range of motion than at the top or bottom. Therefore, if you really wanted to apply maximum load to the tendons you would stop the bar around halfway down and then suddenly drive it back up.
The key to plyometrics lie in the speed, as the force you exert on the bar is determined not only by the weight that you're lifting but also by how fast you're lifting it. Consider the basic physics:
If you lift 100 kg at an acceleration of 1 m/s^2 then you are producing 100 x 1 = 100 N of force.
If you lift 50 kg at an acceleration of 2 m/s^2 then you are producing 50 x 2 = 100 N of force.
So you can lift a light weight faster than you can a heavy one, but if the bar speed is high enough with the light weight the force applied will be the same. The point is if you accelerate the weight quickly you are dramatically increasing the force that the muscle is required to produce. If you think about a yo-yo you'll get an intuitive idea of how this works - when the yo-yo is at the bottom you yank up suddenly, drawing the rope tight. The yo-yo feels much heavier at that point than it actually is. That's a plyometric. For the above speed reasons plyometrics are usually done with weights around only 60% of your one rep maximum.
From a tendon strengthening perspective, if bar speed can be kept sufficiently high, high reps in these sets would provide more of an adaptative stimulation than low reps. This is probably where the false theory that the performance of high reps itself can strengthen tendons comes from. The fact is that high reps, with a quick reversal from eccentric to concentric on each rep, simply provide more repeated stress to the tendons than low reps. High reps with a slow rep cadence, which eliminates the sudden application of force anywhere along the range of motion (e.g. 'Superslow' training), would do little to strengthen the tendons. But, if you are able to perform 10 reps plyometrically with 60% of your one rep maximum while keeping bar speed high on all reps then this would stimulate more tendon strengthening than a 3 rep set. For a power athlete, however, it might make more sense to just do several 3 rep sets. This would allow the trainee to avoid neurological fatigue and glycogen depletion and effectively target the high-threshold fibers while still providing the strengthening stimulus to the tendons. And, realistically, you wouldn't be able to maintain the necessary bar speed for 10 reps anyway.
Another benefit of plyometric reps should also be mentioned: By accelerating the weight as quickly as possible you are 'teaching' your nervous system to voluntarily recruit as many of the highest threshold fibers as possible and to fire these fibers with maximum frequency. This could be extremely beneficial in power training.
This discussion of forces produced and bar speeds leads me to the next method of strengthening tendons: Isometrics.
Isometrics
These are when you simply hold the bar in one place. Pushing against a wall would also be an example. The key is that you suddenly exert maximum force against the object. In the above Bench Press example you would perform them in a power rack and push the bar as hard as you could against the pins. Once again the tendon goes suddenly from a state of having no load (practically) placed upon it to maximum load in a matter of milliseconds. Since the bar is being pushed against the immovable pins you wouldn't even need to place any weight on the bar (although you might want to do this in order to mimic the 'feel' of a regular Bench Press). And as far as range of motion is concerned, because tendons don't contract they don't need to be trained through the muscle's full range of motion.
Once again, for maximum loading of the tendons it would be wise to do this at the involved muscle's point of optimum force production (roughly halfway up the Bench Press range of motion).
How long should you hold an isometric? Well, it's the sudden tendon stretch that we're after, NOT the total amount of tendon stretch, so 2-3 seconds should suffice. In fact, any longer than this and the phenomenon of creep may occur in the tendon and, while this may result in more flexibility (think yoga), it won't do anything for strength and power (the same situation would also occur in the 'Superslow' training method mentioned above).
A word of warning: This type of training can cause dangerous increases in blood pressure. For this reason, it is not recommended that isometrics be held any more than six seconds. This increase in blood pressure is due, at least in part, to holding one's breath during the exertion.
Heavy Negatives
Heavy negatives don't allow the trainee to as suddenly place loading on the tendons as do the above methods. For this reason they are not as effective a tendon strengthener as plyometrics and isometrics. As with plyometrics, they do have the benefit of allowing you to track your progress, though. With an isometric you don't really have a quantitative way of measuring your efforts. Negatives and plyometrics allow you to measure the amount of weight on the bar this session as compared to the last.
Their execution is relatively simple: Load the bar with more weight than you can lift concentrically (you are usually about 20% - 40% stronger in the negative than the concentric) and lower the bar under control. Use enough weight so that the bar forces its way down relatively quickly (after all, we're after tendon strength here) but not so much that you can't maintain full control.
Another thing that should be realized is that negatives have been shown to do substantial 'damage' to the muscle cell and, therefore, markedly lengthen recovery time.
Incorporating One Of The Keys To Strength And Power
I hope I've convinced you of the importance of tendon strengthening here. And it doesn't have to take up much of your training time. Keep in mind that isometrics and negatives are done at force levels exceeding your full-range, concentric, one rep maximum. This means that your nervous system will be going crazy during the exertion (remember the Training To Failure: The Good, The Bad And The Reasons article?). This type of training, therefore, must only be done infrequently. On the other hand, if the weight is kept low (~60% of your one rep max.) and the reps low also (2-3), you can probably get away with plyometrics twice a week (the amount of contractile force you will be able to produce will be limited by your nervous system's ability to voluntarily recruit and twitch the higher threshold fibers - the sudden reversal of motion, however, still delivers a very high impulsive force to the tendons).
But before you dismiss isometrics in favour of plyometrics totally, consider this section from the article Are Partial Range Movements Useful?:
...there is strong research and anecdotal evidence to suggest that a muscle can be made stronger in a very specific position by training it in that position...
and
...it can be very useful in training sticking points in lifts.
So if you wanted to kill two birds with one stone you could use isometrics to strengthen sticking points and also enjoy the carry-over effect of increased tendon strength. Keep in mind, though, that it's not necessarily true that your sticking point will be at the muscle's optimum force production point and that, in order for maximum muscular stress, the isometrics for training this range should be closer to 6 seconds than 2-3.
As far as the plyometrics are concerned I believe Louie Simmons' method of performing a second 'light', 'speed' day between heavy sessions in certain exercises is a very efficient idea. This method allows you to train the nervous and muscular systems for sudden force production (as needed in all power events) and to practice the specific skill of the lift while also providing a good adaptative stress to the tendons. One could always perform this style of lifting after your other sets on your 'heavy' day, however, and skip the 'light' day - this would be very beneficial for lifters who train an exercise heavily more frequently than once every seven days.
A word of warning: Due to the sudden force applications these forms of training can be dangerous! If great care isn't taken to warm up properly and to practice STRICT exercise form it is quite likely that you'll strain or tear a muscle! Overtraining will also increase this likelihood.
