The last time we talked, I bombarded you with all kinds of information on the nervous system. Now it's time to translate that into your love-hate relationship with the bar.

Recruitment Doesn't Matter, Speed Does

Sure, more motor units equal more force production. Or does it?

The majority of research supports that all motor units are recruited by 60% maximal voluntary contraction (MVC) in small muscles (13-15) and by 85% MVC in larger muscles.(3, 13, 16, 17) Of course, there's always an exception. There's some evidence that additional motor units are recruited above 90% in the biceps brachii (G. Kamen, personal communication, 2008), but again, this is by far the exception.

Interested in how this relates to maximal force production? In trained lifters, the majority of maximal strength gains will come from work at intensities above 85%. This means that all the motor units in both the small and large muscles contributing to that movement will be recruited.

curls

In other words, improved recruitment won't lead to further gains in maximal strength because there's nothing left to recruit! The main way the nervous system produces more force at these levels is by increasing the firing rates of all the recruited motor units, especially the high-threshold motor units that were most recently recruited.

Alright, maybe this section shouldn't have been called "Recruitment Doesn't Matter." I'll admit it, recruitment does play a role. If you're training to increase maximal force production, you need to train at an intensity over 85% in order to maximize recruitment.

I'm sure some of you don't agree with that, so go ahead and shout, "I've gotten stronger using lighter loads!" Remember that in lifters with a young training age, everything works. Circuit training, bodyweight training, and 5 x 5 programs all lead to significant strength gains. Set, rep, and intensity combinations aren't nearly as important for someone who's been training for a few years as they are for someone who's been training for over five years.

Bar Speed: Actual vs. Intended

Speed of movement is one of the most important factors related to strength gains. Actually, intended speed of movement is the real key. What's the difference? We've established that maximal strength training should be done above 85%, while including sets over 90% for best results. Those of you who have moved a weight above 90% understand that no matter what your intentions are, the bar isn't going to move quickly. The actual bar speed doesn't matter – the intended bar speed does.

Not only does maximizing the intended concentric (positive) phase of the lift maximize intramuscular tension, it also leads to unique neural adaptations. Specifically, maximizing intended contraction speeds leads to an increased rate of force development, increased doublet firing, and decreased motor unit recruitment threshold.(10) This is true of dynamic and isometric contractions.(10, 18-20)

The fact that these adaptations occur with isometric contractions is further evidence that the actual bar speed isn't as important as the intended bar speed, as there's no change in total muscle length in isometric contractions.

Decreasing the recruitment threshold may have positive implications on force production due to a maximal firing rate ceiling effect. If a high-threshold unit is recruited late in the contraction, it only has a small amount of time to increase its firing rate and therefore increase force production. If the high-threshold unit is recruited sooner in the contraction, as it would be with an intended high velocity contraction, it has more time to increase its firing rate and increase the amount of force produced.

Enough Science, How Do I Get Strong?

While I'm fascinated by the neural adaptations to exercise, I realize that some of you may not be. So let's get to the fun stuff. How can we use what we know to manipulate the nervous system to make us as strong as possible?

There are three things I've found most people don't do that result in quick increases in maximal strength.

Focus on Tempo

Control the bar through the eccentric (negative) phase and explode through the concentric (positive) phase. If you're benching, this means lowering the bar down to your chest under control and pressing it as quickly as possible. Take this concept and apply it to all of your lifts.

You may find you can't do as many reps this way as you can if you moved at a more comfortable pace. That's okay. We're after maximal strength increases, not endurance adaptations.

Perform Singles and Doubles Over 90%

If you want to get strong, you need to lift heavy things. This seems like an obvious concept, but many lifters don't do enough of this.

power lifter

This won't hold true for everyone, but most people can do around three reps at 90% intensity. By doing six to eight sets of one or two reps at or above 90%, you can focus on the quality of the movement without reaching technical failure. Teach your nervous system to expect repetitive near max efforts and you'll experience quick jumps in strength.

Overshoot Your Working Intensity

Warming up is receiving more attention than it used to, for good reason. A high quality warm-up will positively influence the rest of the workout. If you haven't purchased Inside-Out by Mike Robertson and Bill Hartman and Magnificent Mobility by Eric Cressey and Mike Robertson, you're doing yourself a disservice.

Following your dynamic mobility and activation work, it's still necessary to warm-up on a specific lift. If you're going to be working at submaximal intensities (which I'll loosely define as below 90%), extend your lift-specific warm-up to a higher intensity than what you'll be using for your work sets.

So, say you're doing a lower body workout that starts with deadlifts for a 4 x 5 set/rep scheme at around 80%. Your max deadlift is 400 pounds, with 80% of that equalling 320 pounds.

Your mobility and activation warm-up might look something like:

Bodyweight squat x 10
Diagonal split-squat x 8 (each leg)
Lateral miniband walk x 10 steps (each direction)
Glute bridge hold 1 x 30 seconds
Reverse crossover lunge x 10 (each leg)
Quadruped hip circles x 6 (each direction and each side)
Glute bridge with miniband x 15

Lateral lunge x 10 (each leg)

Moving over to the platform, your deadlift-specific warm-up would look like this:

135 x 5 (35%)
225 x 3 (56%)
275 x 1 (68%)
315 x 1 (79%)
355 x 1 (89%)
320 for your 4 x 5 (80%)

This overshoot in intensity increases the descending drive to the working muscles. Neural mechanisms aside, just give it a try. I've found that my perceived effort at any given intensity is significantly lower when I follow an overshooting warm-up, as opposed to when I don't (for example, stopping the warm-up at the 275 x 1).

As an added benefit, you're reinforcing near max efforts on a sub-max intensity day. The more you tell your body it needs to produce high amounts of force, the more it'll adapt to do so.

Time to Set Some Records

After delving into the nervous system and making it out alive with some techniques to apply, I bet you're itchin' to hit the gym. Go hoist some iron and demolish those old personal bests.

References

1. Griffin, L., & Cafarelli, E. (2007). Transcranial magnetic stimulation during resistance training of the tibialis anterior muscle. Journal of Electromyography and Kinesiology, 17(4), 446-452.

2. Aagaard, P., Simonsen, E., Anderson, J., Magnusson, P., & Dyhre-Poulsen, P. (2002). Neural adaptation to resistance training: changes in evoked V-wave and H-reflex responses. Journal of Applied Physiology, 92(6), 2309-2318.

3. Milner-Brown, H., Stein, R., & Yemm, R. (1973). The orderly recruitment of human motor units during voluntary isometric contractions. Journal of Physiology, 230, 359-370.

4. Henneman, E. (1985). The size-principle: a deterministic output emerges from a set of probabilistic connections. The Journal of Experimental Biology, 115, 105-112.

5. Kernell, D. (1966). Input Resistance, Electrical Excitability, and Size of Ventral Horn Cells in Cat Spinal Cord. Science, 152(729), 1637-1640.

6. Traub, R. (1976). Motorneurons of different geometry and the size principle. Biological Cybernetics, 25(3), 163-176.

7. Buller, A., Mommaerts, W., & Seraydarian, K. (1969). Enzymic properties of myosin in fast and slow twitch muscles of the cat following cross-innervation. Journal of Physiology, 205(3), 581-597.

8. Buller, A., Kean, C., Ranatunga, K. (1971). The force-velocity characteristics of cat fast and slow-twitch skeletal muscle following cross-innervation. Journal of Physiology, 213(2), 66P-67P.

9. Semmler, J., & Nordstrom, M. (1998). Motor unit discharge and force in skill- and strength-trained individuals. Experimental Brain Research, 119, 27-38.

10. Van Cutsem, M., Duchateau, J., & Hainaut, K. (1998). Changes in single motor unit behavior contribute to the increase in contraction speed after dynamic training in humans. Journal of Physiology, 513, 295-305.

11. Halonen, J., Lang, A., & Partanen, V. (1977). Change in motor unit firing rate after double discharge: an electromygram study in man. Experimental Neurology, 55, 538-545.

12. Carolan, B., & Cafarelli, E. (1992). Adaptations in coactivation after isometric resistance training. Journal of Applied Physiology, 73(3), 911-917.

13. De Luca, C., LeFever, R., McCue, M., & Xenakis, A. (1982). Behavior of human motor units in different muscles during linearly varying contractions. Journal of Physiology, 329, 113-128.

14. Kukulka, C., & Clamann, H. (1981). Comparison of the recruitment and discharge properties of motor units in human brachial biceps and adductor pollicis during isometric contractions. Brain Research, 219, 45-55.

15. Van Cutsem, M., Feiereisen, P., Duchateau, J., & Hainaut, K. (1997). Mechanical properties and behavior of motor units in the tibialis anterior during voluntary contractions. Canadian Journal of Applied Physiology, 22, 585-597.

16. Duchateau, J., & Hainaut, K. (1990). Effects of immobilization on contractile properties, recruitment and firing rates of human motor units. Journal of Physiology, 422, 55-65.

17. Moritz, C., Barry, B., Pascoe, M., & Enoka, R. (2005). Discharge rate variability influences the variation in force fluctuations across the working range of a hand muscle. Journal of Neurophysiology, 93, 2449-2459.

18. Aagaard, P., Simonsen, E., Anderson, J., et al. (2002). Increased rate of force development and neural drive of human skeletal muscle following resistance exercise. Journal of Applied Physiology, 93, 1318-1326.

19. Gabriel, D., Basford, J., & An, K-N. (2001). Training-related changes in the maximal rate of torque development and EMG activity. Journal of Electromyography and Kinesiology, 11, 123-129.

20. Maffiuletti, N., & Martin, A. (2001). Progressive versus rapid rate of contraction during 7 wk of isometric resistive training. Medicine and Science in Sports and Exercise, 22, 1220-1227.