Category Archives: Power Training

Science of strength!

In this post I will discuss the physiological components that make up physical strength. In general the strength of a muscle is determined by its cross sectional mass. When we assess the improvement of strength in a muscular contraction, we see a significant increase in force output in a short space of time with no change in mass. This shows us that there is also a neural component that plays a significant role in strength. In order for a muscle fiber to hit a peak contraction it must be stimulated fully. A beginner to strength training will be unable to reach his true max because he will be neurally untrained. This means he is not capable of using all his muscle fibers or even capable of using the select few to their full potential.

When we want to move, we send a chemo-electrical signal from brain to the muscle which results in a contraction. The more signals we send the more forceful the contraction. In order to achieve maximum contraction we must have a constant and rapid train of impulses coming from our brain. The route the impulse takes down the nerves must be capable of sustaining and transmitting these signals. Early in our training it is these nerves which improve at delivering stimulus, that results in strength improvements.

There are several factors which can prevent us achieving maximum contractile forces. We have safety mechanisms which prevent us reaching our limits in order to prevent damage to our muscle tissue. These mechanisms are largely involuntary and are not simply a case of pushing harder. When we train the thresholds for these “safety switches” raise, allowing us to lift more. This is partly because our muscles become more conditioned and less susceptible to damage but also because our overriding mechanisms improve. We can prove this theory by using a simple maximum voluntary contraction test on a muscle. An athlete produces their strongest contraction and when it peaks we add extra stimulus externally with an electric impulse. The peak will increase significantly higher than voluntary stimulus could achieve, proving there is more force possible.

So how do we increase strength? There a couple of areas which can be improved. First we need to train the movement. Becoming more accustomed to the movement helps us learn the pattern of muscle activation required to perform the action effectively. Second we must improve stimulation and muscle activation. The obvious method is working closer to our maxes which in theory requires a “close to max muscle contraction”. Become accustomed to producing maximum force will improve the mechanisms involved over time. This can be taxing on both the central nervous system (CNS) and the muscle structure itself. It will require structural recovery which takes time. Speed training is an excellent variation as it allows us to improve the rate of impulses coming from the brain. More ballistic type exercises such as jumping are a good way to improve rate of neural transmission. Adding bands or chains to sub-maximal weights for particular lifts can also be another variation to include. The increased resistance over the range of the movement requires an accelerated contraction.

Adding chains can be very effective at improving neural components involved in strength. Photo source: www.clintdarden.com

Adding chains can be very effective at improving neural components involved in strength. Photo source: www.clintdarden.com

These types of training are excellent ways to improve the neural component of strength without needing any structural recovery. They are demanding on the CNS and as always adequate recovery is necessary. The next area to work on is increasing muscle mass. This involves hypertrophy of the muscle fibers which occurs over a much longer period of time.

Becoming strong is important to all athletes but understanding what makes them strong can be just as important. The body adapts quickly and so a multidirectional approach can help progress in terms of consistency. Often athletes employ the maximal lifting approach exclusively and plateau quickly. Combining different methods over a periodised training plan can make sure that an athlete continues to improve in the long term and achieve full potential.

Post Activation Potentiation

Also referred to as a PAP response, Post Activation Potentiation has been a tool in an athletes training arsenal for decades. The basic theory is that if you lift a heavy weight you can perform a more explosive contraction soon after. So for example you might do a heavy double on back squat. Immediately after you may do box jumps or something similar and exceed expected performance. The underlying mechanism explaining this is actually quite simple. When you perform a heavy lift or contraction you must activate larger motor units to produce a more forceful contraction. These larger motor units are often referred to as type 2 muscle fibers. These fibers are generally larger and have greater capacity to produce force than smaller fibers. When activated they become slightly more sensitive to further activation for a short period of time after. When you go to perform the next contraction it will be relatively easier to produce force as these motor units are “excited”. Due to changes in sensitivity, the rate of contraction may also be significantly improved. This allows for a better power production overall.

Not a bad example to use. Photo by Hookgrip at www.hookgrip.com

Not a bad example to show. Big lift allows for a big jump!  Photo: Hookgrip at www.hookgrip.com

Not only can this PAP response be useful for improving power, it can also help improve strength endurance. I use the term endurance loosely there. It may allow you to perform more reps at sub-maximal loads without directly influencing fatiguing factors. For example, max repetition bench press is a common test used by many contact sport teams used during team physical testing. One or two singles close to max effort prior to the test can in fact improve the result. This is provided that the athlete does not go overboard and induce fatigue prior to the test. Often the athletes state that the weight initially feels lighter in comparison to a standard work up, warm up protocol. The PAP response can also be used in a hypertrophy program where back off or drop sets are being utilised. This is quite simply due to larger motor units being pre-activated, making a more effective use of available motor units, resulting in an improved performance. Larger volume in terms of weight lifted per session translates well into these types of programs.

While this is not a new concept or theory, the underlying mechanism is often overlooked and therefore under utilised. It is quite an effective tool and one which I have seen positive results from. Having an understanding of this concept allows a coach to be a little more creative in finding ways to help an athlete reach their potential.