There are many different components to exercise that you can change and alternate to gain more efficiently. There are so many variables that it can get a little mind boggling but research has shown muscle growth is greater when the time under tension is greater to an extent. This is because more strain is placed on the muscle fibres. The body is an amazing thing when we exercise at a greater intensity and push to failure. More muscle fibers are damaged. Our body reacts to this by repairing those fibers and growing more so that when we encounter the same intensity again our body will not fail us. This principle is the key to muscle growth. To push hypertrophy, strength and performance to the max and grow more efficiently we can manipulate the time under tension by changing the tempo.
Tempo is the rate at which the isometric, eccentric and concentric phase occurs. When executing an exercise, there is a isometric phase, eccentric phase and a concentric phase. The eccentric phase is the lowering movement of the exercise (the opposite to the contraction movement) and the concentric phase is the lifting movement (the contraction movement) . Isometric phase of a contraction is a hold or a pause.
Tempo is written as;
Eccentric – Pause – Concentric – Pause.
So for example, when doing a bicep curl the eccentric phase, the first number, would be lowering the weight. The second number would be the time the weight stays in the bottom position once it has been lowered. Concentric phase, the third number is the time taken to lift the weight. The fourth number is how long to pause for when the weight is at the top of the lift.
It is popular to extend the eccentric phase to last 2-3 seconds (2-3 human seconds not Mississippi ) with the concentric phase lasting 1 second it should be explosive with no pause in between, 3010.
By varying the tempo you can strengthen weaker movements /muscles simply by increasing the time under tension which is usually the eccentric phase, as most of us spend more time focusing on blasting out powerful moves. Strengthening the weaker movements will in turn improve overall strength, getting you to those 6 plate deadlifts quicker! It also prevents your body from getting used to the same workout as the stimulus varies which equals breaking plateau which equals more gains!
Focusing on tempo is a great way to train as it contributes to the development of body awareness (feeling the muscle work) and greater body control as there is more focus on engaging muscles rather than bouncing out of squats which puts a lot of pressure on joints and connective tissue. Overall, it improves the quality of exercise movements and due to these above factors, it reduces the risk of injury, letting you train through life without niggling wrist sprains, rota cuff tears or worn out cartilage.
The more you vary your training routine the less adaptations are made and so your body is always growing.