Q: Is there a direct correlation between size and strength? I'm a wrestler and would like to stay in my weight class but I also need to get stronger. How strong can a person get before they need to gain weight?
Yes, in general there is a direct correlation between size and strength specific to the individual but it's a little more complicated then that. Two people can have nearly an identical build and be identical in size but one can be stronger then the other. That's because strength is influenced by things like motor unit recruitment, leverages, muscle fibers, endocrine factors and a host of things unrelated to size.
Each muscle fiber is conrolled by a motor unit. To make it simple strength occurs as you learn to engage or recruit motor units by lifting heavy loads. Lifting heavy loads allows you to "practice" and get better at recruiting motor units in a given movement. An untrained individual may typically only be able to recruit 50% of their available motor units so strength can easily double without an increase in size as they learn to engage more of what muscle they have. However, once you are able to recruit nearly all of your available motor units the only way to get stronger is to create more muscle so that the muscle fibers your motor units control are bigger and the same motor unit recruitment can produce more horsepower.
The reason powerlifters are stronger than bodybuilders is because they have superior muscle motor unit recruitment. Even though they may not have as much muscle they are able to use what muscle they do have more effectively. Also, when it comes to size not all size is the same. There is sarcoplasmic muscle growth which is basically just expansion of fluid within a muscle. This type of growth produces "size", but it has no function. Then there is myofibrillar muscle growth which is growth of the actual protein filaments in the muscle cell. This is "functional" size. The first type of growth is enhanced by high rep/lower weight "bodybuilding" protocols and the 2nd type is enhanced by high load/lower repetition strength training protocols.
Knowing this you should be able to see that you can actually increase sarcoplasmic muscle growth and get bigger, but if you neglected lifting heavy loads your motor unit recruitment could actually decrease from lack of practice causing you to get bigger and weaker at the same time! You see this play out quite often when powerlifters and bodybuilders decide to switch sports. Powerlifters take up bodybuilding and often get bigger but weaker. Bodybuilders take up powerlifting and get smaller but stronger.
Now, to determine if you're able to "use" all the size you do have and determine whether you need to gain more muscle weight to increase strength you can get a rough approximation by comparing your maximal eccentric strength to your maximal concentric strength. Pick a movement and compare how much weight you can perform in regular down and up fashion vs how much you can lower under control using a slow 6 second negative. Most will be able to "lower" a lot more weight then they can "lift". If the difference is 10% or less you're most likely pretty close to maxing out your strength in relationship to your size and could benefit by getting bigger. If the difference is greater than 10% you still have more strength to gain before you become maxed out for your size.
Q: What's your take on cardiovascular activity for enhancing speed and power? Do you feel for a pure explosive athlete (thrower), non-quality work would be counter productive to the development of fast twitch fibres i.e. anything which isn't performed for maximum fast twitch fibre contraction or recruitment: Maximal/ Max Speed/Rate of force development oriented movements such as GPP, bodybuilding or any other low intensity work. Thanks a lot.
I think in the short term yes, low intensity work is detrimental. That is, if you take a very strong, powerful, and fast, yet deconditioned athlete and have him do a bunch of low intensity fitness work you can probably expect this to initially decrease his explosive ability until he adjusts to it. However, long term some low intensity, tempo, or work capacity development work is necessary as it will allow one to tolerate more high intensity work and has enough benefits to make up for the negatives. Afterall, if you're so out of shape that you can't walk 10 yards without getting out of breath you're probably gonna have a hard time handling the training necessary to increase your performance - regardless of how fast twitch you may be.
You want to improve your fitness and get some of the benefits without the negatives. According to world renowned sprint coach Charlie Francis, the increased capillarization that comes from aerobic and low intensity work allows the muscles to generate extra heat during activity that lowers the electrical firing threshold of muscle motor units so that a given neural impulse will net a stronger contraction. This will actually allow more fiber to act as fast twitch. This can be evidenced if you've ever done high intensity EMS. Using a given intensity the muscular contractions that come after the 3rd rep or so will be stronger because of increased heating in the muscle. This is also the reason why a lot of sprint world records are broken when the athlete is in the beginning stages of a cold. The increased heat intensifies contraction. As far as I know this theory is based off indirect evidence but his system definitely gets real world results. Whether an individual engaged in some aerobic training could get increased muscle heating and fast twitch muscle expression vs an non-aerobically trained individual who just engages in a good warm-up I have no idea.
John Parillo also recommends lots of aerobic activity for bodybuilders who have reached a plateau for generally the same reasons. Increased capillarization to the muscle means the muscle can take in more nutrients therefore leading to greater size - as long as enough calories are ingested. This is something I have seen and experienced firsthand.
However, there are still other benefits of some cardiovascular activity. It will increase recovery from intense activity and provide a circulatory effect that mops up the damage from high intensity activity like strength, power, and speed work which tends to be anti-circulatory. This is why baseball pitchers have long used cardiovascular training for recovery enhancement. Improving overall fitness will also increase work capacity to allow one's adaptability rate to increase so they can tolerate more training volume. Also the effects on body composition can't be ignored. Low intensity activity stimulates the metabolism and provides nutrient partitioning benefits allowing one to shuttle more calories into the lean compartment, burn more fat, and eat more without becoming fat. Obviously for those who like to eat it definitely makes it a lot easier to become and stay lean.
As an athlete in an explosive sport The trick is to develop and maintain work capacity without causing negative adaptations as you mention. However, initially something has to give so some impacts on absolute peformance can be expected - that's what a (GPP) General physical preparation phase is for. The volume necessary to build up a high level of general fitness may initially be detrimental, but remember it takes far less volume to maintain a quality then to increase a quality. After building up general fitness then you can maintain that fitness with far less volume and you will now have an increased capacity to adapt to all work.
There is a lot of potential for benefits but there is a fine line between the right amount and too much or too much adaptation in the wrong direction. This work should be of fairly low intensity of never more then 70% max effort. You want to stimulate the slow twitch fibers while maintaining the fast twitch. This means that you should make an effort not to fatigue the fast twitch. Recruiting a lot of fast twitch fibers and creating lots of lactic acid during low intensity work will definitely cause a loss of speed, power, and strength so going for a low intensity jog would actually be better then going out and doing max speed intervals with short rests. Medium speed intervals with medium rests such as 3 sets of 100 meter runs x 5 with 45 second rests at 70% max speed would be even better.
I recommend varying the type of exercise with an alternation of mainly lower vs whole body and upper body varieties. For example: bodyweight calisthenic exercises one day, heavy bag rounds or sledgehammer rounds the next day, tempo sprint circuits the next day, low intensity weight training circuits the next day etc.