Tempo
In strength training, one of the most overlooked factors is the tempo, or speed of each rep. Whilst the number of sets and reps performed tend to be in the forefront of trainers (and trainees) minds, neglecting to understand the importance of lifting speed can have dire consequences on your results. On the flip side, careful manipulation of tempo can reap huge benefits.
Tempo Designation
In our articles and programs, you will see that we have a four digit designation that prescribes the tempo. First developed by Australian strength coach Ian king utilising three numbers, Canadian Charles Poliquin further developed this into the four number designation we use today, useful in describing the four components of a repetition.
We will refer to the tempo as a four digit designation, as an example; 4 – 1 – X – 2
The first digit will refer to the time of the eccentric (lengthening) component in seconds.
The second digit will refer to the time of the pause, if any, at the end of the eccentric component in seconds
The third digit will refer to the time of the concentric (shortening) component, in seconds. If the designation is an X, then this will refer to an explosive concentric, performed as fast as possible (maximum force).
The fourth digit will refer to the time of the pause, if any, ant the end of the concentric component.
Whilst the manipulation of each component is subject to many factors, for the case of this article, we will concentrate on the Eccentric and Concentric Tempo (First and Third Numbers).
Eccentric Tempo
In most commercial gyms, and even in some higher end private facilities, you will see trainees usually fail to control the eccentric portion of the rep, almost dropping weights onto the chest before pressing, failing to control the lowering of deadlifts, and making rows look like some weird whole body heave. This is a huge mistake, for many reasons.
With isotonic training, that is, training with both a concentric and eccentric, the load is basically dictated by the concentric capability. Without the ability to lift the load, there is no eccentric, the set stops.
During the eccentric component, there is a reduction in motor unit recruitment, in some instances by up to 50% over levels used in the concentric. Biomechanically, this means that the load on each motor unit is now dramatically increased, as it is dispersed over fewer numbers. Furthermore, the units left behind to eccentrically contract are units of fast twitch, high threshold nature, with large potential for force production adaptations.
Now, it requires more force to lower a weight slowly as it does to lower the same load quickly. So it makes sense to perform a slow eccentric, as it requires a higher force production, a greater recruitment, and overall stress, of high threshold, fast twitch fibres.
How slow? A good rule of thumb is for long range of motion exercises like squats, deadlifts and chin ups, a 4 or 5 second slow eccentric is indicated. Shorter range exercises can use a 3 or 2 second slow eccentric.
If you are worried that changing to a slower eccentric will negatively effect the load you can use, it will. However, soon enough, the adaptations specific to the eccentric will have a carry-over effect to your concentric, aiding in strength.
Concentric Tempo
When training for strength adaptations, it is imperative to use maximum force and explosiveness on the concentric, regardless of the actual speed the bar is moving. When looking to achieve maximal impact with strength adaptations, we are looking to achieve A) a large recruitment of muscle fibre, and B) those fibres recruited being predominantly Fast Twitch (Typle IIB). The magnitude of motor unit recruitment is dictated by the force output, which in turn is governed by the external load and intent to accelerate that load. Large amounts of force development are not present unless a substantial load is in place.
Therefore, to achieve adaptations specific to the recruitment of increased fast twitch motor units, one must use the most explosive concentric as possible, using heavy weights.
This can be prescribed by the designation X, on the third number in the Tempo prescription. Prescriptions of 1 second or more result in a lower force output, lower load and lower motor unit recruitment, but with higher repetitions, this may be an advantage to provide a longer time under tension, given that lower loads are used in higher repetition protocols regardless.
Conclusion
One of the tips I give to coaches I educate is to standardize as many programming variables as possible, therefore enabling decreasing the impacts on changes that are made. Tempo is one that I encourage minimal changes across a macro-cycle, especially if the coach is more inexperienced; this way you can be sure that the fluctuations in sets and reps are actually creating the changes you want, without changes in tempo confusing the situation.
If using heavy loads, with large, multi joint compound lifts, use a slow eccentric tempo, with a fast, explosive concentric (designated by an X). If using smaller exercises, for higher reps aimed at hypertrophy, use a slightly shorter eccentric tempo, and back off the explosiveness on the concentric, and use a one second count. Even if you change sets and reps, and exercises across a macro-cycle, try and keep the tempo the same for each type of lift.
So there we have it. Know what tempo to use for what lift, and watch the effectiveness of your training program soar!