Not a day goes by that I don't get several questions about terms like speed-strength, rate of force development, explosive strength, reactivity, and power. In my experience they're responsible for more than a tad bit of confusion amongst trainees and coaches.
Let’s talk for a moment what these terms really mean. Really they're all pretty much demonstrated in the real world as the same thing: Producing maximal force in minimal time.
Generating maximal force in minimal time is dependent upon 3 things:
A: Body type and limb length: For the same reason you can hit a baseball further with a 32 inch bat then a 10 inch bat, differences in body type change leverage, and change how much force you can express in any given task.
B: Neural efficiency: How efficient you and your nervous system are at firing and coordinating the muscles involved in a movement
C: Muscular factors: Are primarily impacted by the size of the muscles you're firing in a particular movement.
Put those 3 things together and you have movement. So, you can enhance sports movements either by boosting neural efficiency, or by increasing the size of your muscles, because limb length and body type you can do nothing about. Well, almost nothing anyway. You can always shed or gain weight, and if you're young enough you can grow taller. But let's focus on the other 2.
First, let's discuss the neural factors of force production.
There are two primary ways the nervous system influences force production. The first process is called motor unit recruitment. Specifically, I'm referring to your nervous system's ability to turn on and fire muscle cells. A motor unit is just a grouping of muscle cells or fibers. A given motor unit may contain a few hundred muscle cells, or it may contain several thousand, and each muscle may be made up of hundreds of motor units. When you decide to move, a muscle a message goes from your brain and down your spinal cord where it eventually reaches and signals the individual muscle motor units to fire. When a motor unit fires so do all the muscle cells under its control. The more motor units (muscle fibers) you recruit, the more force you'll produce. Small force tasks recruit few motor units; large force and/or explosive tasks recruit many motor units. Full muscular recruitment occurs when maximal force output reaches around 80-85% of your maximum.
So, if your 1 repetition maximal arm curl is 100 pounds and you perform a set with 80 pounds (80%), you'll be recruiting, or firing, all of the motor units and muscle fibers in the biceps.
How The Nervous & Muscular Systems Work Together
Quickly, let's go over how the nervous system and muscular system work together to produce force. Obviously, before a muscle cell can contract, it has to be recruited, or turned on, by the nervous system. Once it is recruited, it always fires with all of its force. How much force a muscle cell generates when it fires is almost solely determined by how much protein is contained in it, or how big it is. Some muscle cells are bigger than others, but how much peak tension a given amount of muscle cells (fast twitch or slow) can generate will always be determined by how much space they take up. In other words, a "slow-twitch" muscle cell might be only half as big as a "fast-twitch" muscle but 100 slow twitch muscle cells can generate the same peak force as 50 fast twitch muscle cells since the total amount of protein they contain is the same.
Depending on the inherent speed of a particular movement, factors like the dominant fiber type of a particular muscle play some role into how much tension ends up getting delivered, as fast twitch fibers build up to peak tension quicker. Fiber type plays no role in slower movements like powerlifting (1-4), but plays more of a role in very fast movements like throwing (5-6). But to keep things on track, anytime you add muscle size, the amount of protein contained in your muscle cells increases and they (the individual muscle cells) get bigger and produce more force than before.
Thus, the tension generated in any movement is determined by how your nervous system can turn on and coordinate your bicep muscle cells during a movement, along with the total amount of protein (size) contained in those muscle cells being recruited.
Thus, you can improve most real world displays of explosiveness by either getting more coordinated or by getting bigger muscles.
The Psycho Factor
There is also one other neural aspect that enhances force production called rate coding, or what I like to call the psycho factor. Rate coding allows your muscles to develop more force by enhancing the frequency at which the neural signals get sent to your muscles telling them to contract. At very high efforts a given motor unit will continuously fire and relax and repeat that process at a very high rate of speed. The repetitive firing of all available motor units occurs so quickly that there is a summation of force and the ability to produce tension is magnified beyond what you get from regular recruitment and muscle protein content. In essence, your muscles get supercharged and are able to generate tension above and beyond what they normally would.
So, why do I call this the psycho factor?
Because it is inherently largely influenced by psychological state.
It's fairly safe to say that under normal circumstances few people are capable of utilizing all of their force potential in a given movement. In fact, an untrained person may only be able to utilize 60% what they're capable of. Why is that? Well, the body normally inhibits the full potential of rate coding as a protective mechanism to protect you from injuring yourself. If your body didn’t have this safeguard in place and you could easily call upon your full force potential you’d definitely very strong and powerful, yet you'd probably also stand a good chance of ripping your tendons right off the bone.
Let's say you have a strength potential of 200 pounds in the leg curl. This means, based on the amount of muscle contained in your hamstrings and your body structure, if all of your available motor units were firing and you were utilizing 100% of your rate coding capacity you'd be able to lift 200 pounds. However, an untrained person might only be able to lift 120 pounds, or 60% of their potential. A highly trained and super motivated (a.k.a adrenalized) person might be able to lift 180 pounds, or 90% of his potential.
The same inhibition of peak performance also occurs with sporting type movements, although the cap on performance is not as great as the strength example.
The Importance of Adrenaline
One of the biggest factors that increases rate coding is adrenaline, or the fight or flight response. It's a mechanism the body uses to ramp up force production under stress.
We all know that when we're excited, really pissed off, or nervous, we seem to be able to function at a different level. The extra rate coding resulting from adrenaline explains why people tend to be stronger, more powerful, and faster in competitive situations. For example, a powerlifter will tend to deadlift a lot more weight in a meet than in the gym. A basketball player will tend to jump higher prior to a big game then in training. A sprinter will tend to run faster at a meet than in training etc. Even trained athletes can have as much as a 10% difference between what they're able to do in a regular non-stimulated setting compared to what they're able to do in a competition effort.
This also explains why those who are naturally very fast, explosive, and powerful often tend to share some common psychological characteristics (ie. explosive temperament or the ability to easily become "adrenalized”). Some people have a natural propensity to have elevated adrenal related discharges from the CNS and naturally have better rate coding, even under non-stressful conditions.
It also explains why the more advanced you become, the less likely you are to be able to match your personal best every single day. A beginner athlete can run, lift, or jump their personal best any day of the week. An advanced athlete, like an olympic sprinter or powerlifter, might have 6 months to a year or more in between their truly top efforts. The greater the exent to which a person can tap into rate coding, the more stressful each effort tends to become, which makes sense as it's largely an adaptation built on the stress response pathways.
Things like testosterone sensitivity in the CNS largely influence rate coding. The best look into natural rate coding capacity in my experience is looking at a persons natural quickness. How fast are your hands. How quickly can you move your feet? Fortunately, with training, one can vastly improve this capacity naturally.
How to improve rate coding:
Imagine taking someone who's never driven a car before out on the track and handing them the keys to a souped up F-1 race car. They might as well be driving a Honda civic, as their lack of driving skills would leave them unable to benefit from the supercharged motor. In much the same way, you have to be coordinated and fluid enough in your movement patterns of choice to benefit from additional supercharging.
Any type of neural related gains you make in force production are fairly specific to the movement. Despite being some of the strongest people in the world in their events of choice, professional weightlifters can't typically execute an iron cross in gymnastics simply because they haven't trained for it. If you want to throw hard you need to optimize your throwing mechanics. If you want to jump high you need to master the act of jumping. If you want to lift a lot of weight you need to lift, and so forth. There are some exceptions and you can get some carryover between different movements but for the most part, practice is the best way to optimize all the neurological qualities contributing to a particular movement.
B: The Stimulation Method
Outside of optimizing movement patterns, this is the most realistic way for the average person to improve the rate coding aspect of neural efficiency, and one I want to focus on. Here you perform one higher tension exercise to really activate or excite the CNS. You then follow it up with an exercise to take advantage of the CNS excitability, which temporarily boosts rate coding. In essence you're "tricking" your nervous system. Think of a baseball player swinging a bat loaded up with weights before he steps in the batters box with a regular bat. The loaded bat allows him to swing a regular bat with greater ease. Not only do you get a temporary boost in performance, but over time the thought is your body becomes more sensitive to the neural discharges from your CNS and learns to accept a new level of force as being normal for a particular movement, even in the absence of psychological excitement. The stimulation methods are also known as post-activation potentiation methods. Here are a few examples:
Stimulation Methods for Jumps
Squat x 2-3 with 90% load - rest 5 minutes
jump squat- x 6-8 with 20% load
Jump with weighted vest or barbell with 10-20% of bodyweight x 5 rest 5 minutes
unloaded jump x 3
Depth jump x 5 from 24 inch box rest 3 minutes
running jump for max height x 3
Squat 2 x 2 at 90-95 % - rest 4-6 min
depth jump- 2 x 5 from 24-30 inch box.
Lightly loaded depth drops (~10% of bodyweight) x 2 rest 3-5 minutes
Bodyweight depth jump for max height x 2
Stimulation Methods For Speed
Loaded sled sprints (or uphill sprint) x 20 yards with 50 pounds x 2 sets rest 5 minutes
bodyweight sprint x 10-40 yards
45 degree back extension or reverse hyper isometric old x 7-10 seconds - rest 3 minutes
10 yard sprint or jump
15-20 minute warm-up with weighted belt or vest equivalent to 5-10% of BW
Stimulation Methods for Strength
Bench press unrack and hold 110% of 1rm at lockout x 5 seconds rest 3-5 minutes
1rm Bench press
Squat walkout x 110% (or more) of 1rm walkout and hold x 10 seconds rest 3-5 minutes
1/4 Squat x 110% of 1rm x 2 rest 3-5 minutes
Snatch grip partial deadlift from high blocks with shrug - x 3 reps rest 5 minutes
Hang Power snatch x 2-3
There are also stimulation methods for throwing a baseball or shotput based on the same principal. They involve throwing heavier implements alternated with lighter.
It should be noted that stimulation methods are most effective for intermediate level athletes. Beginners don't benefit as much because their nervous systems are unable to clearly ramp up force production from one movement and carry it over into another. Their nervous systems are unable to really differentitate the load between the 2 movements effectively. Advanced athletes can benefit, but not as much as intermediates because they don't need them - their nervous systems are psycho enough already without any external "tricks". That leaves these methods most effective for intermediate level athletes.
How do you tell which group you're in? If in doubt play around with some of them and see.
Get Fired Up!
For enhanced effectiveness use stimulation methods in a high state of arousal. Many will not require any external assistance getting fired up for competitions. For regular training a stack many have found successful consists of taking the following 30 minutes prior to a workout:
caffeine 200 mg
l-tyrosine 3000 mg
acetyl-l-carnitine 1000 mg.
Caffeine on it's own is plenty for most people, but a variety of other stimulants can be effective. You know you're stimulated enough when your eyes are as big as saucers and your hair begins to stand up on end. You know you've gone overboard when your nose starts to bleed and you start hearing and seeing things - not that I know that from past experience. :) If in doubt it's better to err on the side of too little than not enough, as overstimulating yourself will have the opposite of the intended effect. Supplements like l-tyrosine and acetyl-l-carnitine can be used every day without any ills, but it's generally a good idea to save the heavier stims (including caffeine) for when you really need them. If you adapt to them they won't work as effectively.
What Not To Do
The stimulation methods like those above are great for promoting immediate personal bests and are great for peaking, however, they also have their drawbacks. Anytime you set a significant PR in a high state of arousal you run the risk of burning yourself out. This is particularly true when someone sets a PR and gets so amped up they continue the same type of training for days or weeks on end trying to match or improve upon the PR. Some of these methods can be used year around in manageable volumes, but it's generally advisable to restrict their use to short 2-3 week cycles when you want to peak. Additionally, anytime you set a big PR in a high state of arousal back off on your training volume and intensity and go easier for at least a week or so. Be smart and don't try to enter every session in an amped up out of this world state of mind or you'll likely start to regress in a hurry.
The concepts I've talked about in this article deal with immediate stimulation - you should expect to see an enhanced training effect within minutes. However, there are also forms of training designed to stimulate latent stimulation, where what you do on day 1 helps to significantly enhance what you do on day 2, 3, or 4. With latent stimulation it is believed the local muscular nerves receive a tonic boost that really kicks in the following days. Heavy weight training, some forms of hypertrophy training, and some shock methods do a good job at this. Here is an article in which Andrew Darqui demonstrates how he used depth jumps as a form of delayed stimulation:
Hopefully you found this article informative. For a more in-depth look at how psycho factor training can be incorporated into a training regime check out my No Bull Speed Development Manual or soon to be available Flyin in 4 routine.
1. The influence of variations in muscle fibre composition on muscle strength and cross-sectional area in untrained males.Maughan RJ, Nimmo MA.
2. Muscle strength from adolescence to adulthood--relationship to muscle fibre types.Glenmark B, Hedberg G, Kaijser L, Jansson E. Department of Clinical Physiology, Karolinska Hospital, Stockholm, Sweden.
3. Muscle fibre type distribution, muscle cross-sectional area and maximal voluntary strength in humans.Schantz P, Randall-Fox E, Hutchison W, Tydén A, Astrand PO.
4. Muscle fiber number in biceps brachii in bodybuilders and control subjects.MacDougall JD, Sale DG, Alway SE, Sutton JR.
5. Leg extension power and muscle fiber composition.Coyle EF, Costill DL, Lesmes GR.
6. Fiber type characteristics and myosin light chain expression in a world champion shot putter.Billeter R, Jostarndt-Fögen K, Günthör W, Hoppeler H. Department of Anatomy, University of Bern, Switzerland.
7. "Supermethods." Verkhoshansky.