Warning: Building tackling power doesn't necessarily mean lifting heavy weights. (See Increase Tackling Power With Patrick Willis's Homegrown Training Secrets.) To harness the power you need to attack like a freight train or push off defenders, you should be training to recruit larger motor units and type IIx muscle fibers.
Motor units are responsible for stimulating your muscle fibers. They're what your body calls upon for explosiveness and power.
Generally they are recruited by increasing force or effort. As your intensity and effort increase, you recruit more motor units, specifically type II muscle fibers and large motor units—the ones that generate the greatest force and speed of contraction.
The smaller the motor unit, the slower its contraction speed and the greater its resistance to fatigue. The larger motor units have the highest contraction speed and lowest resistance to fatigue.
For example, on a scale of 1 to 200, say your pectorals muscles have 200 motor units. For a movement requiring little force but precise control, the motor unit ranked number one would be recruited. As force production requirements increase, so do the numbers recruited, all the way to the motor unit ranked 200 with maximal muscle contraction and force.
To break it down even further, think of it this way:
Small motor units and type I muscle fibers
Marathoner coming at you? No problem. One little push will do.
Large motor units and type II muscle fibers
Sprinter coming at you? Better be prepared.
Largest motor units and type IIx muscle fibers
Sprinter coming at you like a full-speed freight train? Serious problem. Start praying.
Bottom line: If you can recruit more fast-twitch muscle fibers and maximize motor unit recruitment, you will be more explosive and powerful.
The following Combat Push-Up circuit is designed to maximize recruitment of large motor units and fast-twitch muscle fibers. Although no weights are involved, the circuit is certainly not easy. You need to have a great push-up base before attempting it.
By doing a series of exercises to pre-fatigue, then finishing off with plyometric Push-Ups when fully fatigued, you maximize motor unit recruitment along with new motor units. Teaching the body to maximize motor unit recruitment can only be done with the right training, and this sequence is one way to do it.
The Push-Up Combat Circuit
A combination of four Push-Up exercises done back-to-back.
- Push-Up Pulses (10 reps)
- Push-Up Side-to-Sides (10 reps)
- Diamond Push-Up (5 reps)
- Push-Up pops (5 reps)
Special thanks to Juan Carlos Santana, CSCS, Msc, for introducing a version of the push-up combat sequence at the 2011 NSCA conference; Matt Baxter of Kovaluk Sports Conditioning; and Adam Philp of Belmont Bulldogs High School Football.
 Adam, A., & DeLuca, C. J., (2003). "Recruitment order of motor units in human vastus lateralis muscle is maintained during fatiguing contractions." Journal of Neurophysiology, 90(5), 2919-2927.
 Sale, D. G. (1987). "Influence of exercise and training on motor unit activation." Exercise Sports Science Review, 15, 95-151.
 Wilmore, J. J., Costill, D. L., & Kennedy, W. L. (2008). Physiology of Sport and Exercise (4th ed.). Champaign, Ill: Human Kinetics.
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