Vary the tempo of each phase of your lifts to develop more muscle and increase strength. Tempo refers to the amount of time you spend raising and lowering the weight. It is an essential component of program development and is just as important as exercise selection or picking a set and repetition scheme.
For example, a recent study in the International Journal of Sports Medicine found that if you don’t control repetition speed, you might not produce adaptation—meaning no results! Researchers compared the effect of bench press training using an explosive tempo with a bench press program that allowed trainees to self-select tempo. After three weeks, the fast tempo group increased 10 percent in maximal bench press strength—very impressive gains in only six sessions! The other group that self-selected lifting speed did not gain ANY strength.
The point is to always have a plan for the tempo of your lifts since different tempos make the body adapt in very different ways. For instance, if you lift moderate to heavy loads with longer time under tension (a four second eccentric tempo and a one second concentric tempo, for example), you would improve body composition and stimulate muscle development. Then, for the next training cycle, if your main goal was to gain strength, you might use heavier weights, fewer reps per set, and spend two seconds on the down phase of your lifts, with an explosive concentric phase.
An older 2006 study from the European Journal of Applied Physiology illustrates the value of tempo for getting results perfectly.
Researchers compared three different training protocols for the preacher curl exercise:
• Protocol A used a load of 90 percent of the 10RM, included 3 sets of 10, and had trainees spend 5 seconds on the concentric phase and 2 seconds on the eccentric phase. Total time under tension was 210 seconds.
• Protocol B used a load of 90 percent of the 10RM, included 3 sets of 10, and had trainees spend 2 seconds on the concentric phase and 2 seconds on the eccentric phase. Total time under tension was 120 seconds.
• Protocol C used half the load used in protocol A and B, included 3 sets of 5, and had trainees spend 10 seconds on the concentric phase and 4 seconds on the eccentric phase. Total time under tension was 210 seconds.
Results of the protocols showed that protocol A produced the greatest fatigue as measured by decrease in muscle contractile properties of the elbow flexors. Protocol B produced the least muscle fatigue. In addition, protocol A was most effective at training the muscles for hypertrophy, as measured by the greatest reduction in peak twitch force of the muscle. Again, protocol B was least effective at inducing adaptations that would result in hypertrophy.
Researchers write that to increase muscle size, the longer time under tension is best, assuming the load is heavy enough. This study showed that protocol C, which used half of the load in protocol A, did produce significant stimulus for hypertrophy, just not as much as the heavier load. This is noteworthy because it can be applied to training special populations, and shows that as long as the weight is heavy enough to overload the muscles, a range of loads can produce hypertrophy if you manipulate tempo correctly.
In comparison, to favor strength development and effectively train the central nervous system, you would want to use a shorter total time under tension (less than 20 seconds for the whole set) and a ballistic or 1-second concentric tempo. This understanding of training effect is supported by a more recent study in the Journal of Physiology that compared protein synthesis following two different protocols of leg extensions.
The first protocol used 6 seconds for both phases of the lift, and the second protocol used 1 second for both phases of the lift. The 6-second condition produced much more protein synthesis than the 1-second condition, and the muscle-building effect increased three-fold at 24 hours after training. The 1-second tempo was superior for increasing neural drive to trigger strength adaptation.
Take away a commitment to always program tempo for your lifts. If you are a trainer, you must count tempo for your clients—they will get better results and training will be more varied. In addition, to trigger muscle building and lose fat, opt for longer tempos and a greater time spent under tension. To increase strength and target the central nervous system, use short tempos with an explosive motion and less than 20 seconds spent under tension.
Burd, N., Andrews, R., et al. Muscle Time Under Tension During Resistance Exercise Stimulates Differential Muscle Protein Sub-Fractional Synthetic Responses In Men. Journal of Physiology. 2012. 590 (2), 351-362.
Tran, Q., Docherty, D., et al. The Effects of Varying Time Under Tension and Volume Load on Acute Neuromuscular Responses. European Jouranl of Applied Physiology. 2006. 98, 498-410.
Padulo, J., Mignogna, P., et al. Effect of Different Pushing Speeds in Bench Press. International Journal of Sports Medicine. 2012. 33(5), 376-380.