Lifting weights is simple. You lower with control and then drive up as powerfully as you can. This is an effective method of training. But it doesn't do much to train one of the three types of muscle contractions, which could be preventing you from reaching your strength and speed potential.
There are three types of muscle contractions:
- Concentric. The shortening of a muscle, as when your biceps shortens as you raise the weight during a curl.
- Eccentric. The lengthening of a muscle, as when your biceps lengthens as you lower the weight during a curl.
- Isometric. Consists of no change in muscle length because the tension produced within the muscle is equal to the opposing force. For example, a Wall Sit or holding the top of a Bicep Curl without moving the weight.
Traditional reps do a great job of training the concentric and eccentric contractions, but they don't do a ton to improve isometric strength.
You can solve this by performing paused reps, such as holding the bottom portion of a Squat for a few seconds. But to take your performance to the next level, I recommend dynamic isometric training.
Dynamic isometric training combines the benefits of isometric and explosive training. Dr. Yuri Verkhoshansky, former Soviet scientist and the creator of plyometrics, found that this style of training was superior to traditional explosive work alone for improving strength and speed.
This training method involves doing exercises with 3- to 6-second holds (isometric portion) followed by explosive dynamic work done immediately afterwards.
When comparing the activation levels of muscles during the three types of contractions, a study showed that concentric and eccentric contractions at maximal levels elicited around 88.3 percent and 89.7 percent activation respectively, whereas maximal isometric contractions elicited 95.2 percent activation. By performing isometrics with explosive intent, one would be training his or her muscles to elicit the highest amount of muscle activation as fast as possible.
A large amount of muscle recruitment done rapidly means more strength and speed. The sport-specific application of this is that athletes often have to react and fire their muscles quickly. Enhancing this ability instantly results in improved performance.
In a study comparing the effects of plyomtetric training and explosive isometrics, similar increases in rate of force development and jump height were observed for both training groups. However isometric training was shown to have reduced impact forces, whereas plyometrics are known to place a large stress on the body. This means explosive isometrics can be used as an adjunct to plyometrics to elicit similar athletic benefits while reducing overall load on the body. This can be a beneficial tool for strength coaches who want to train power during the competition season in a manner that's not as taxing on the joints and ligaments.
Isometric contractions occur in many sports where you have to actively push/pull against opponents' bodies or in sports that have stop-and-go components when athletes are required to explode from dead stops. Examples include a wrestler tangled in a clinch who immediately shoots for a takedown after seeing an opening; a tennis player exploding from a crouched position to return a serve; and a sprinter waiting to take off at the starting line. In these instances dynamic isometric training literally occurs on the playing field.
You can utilize dynamic isometrics in two fashions for general movements and sport-specific preparation:
- Hold a Goblet Squat in the full squat position for 3 seconds and then follow up with 3 reps done explosively.
- Hold a Chin-Up position for 3 seconds and then follow up with 3 reps done explosively.
- A running back holding a stance similar to one he takes when performing a cut and contract isometrically for 3 seconds before completing the action.
- A thrower holding resistance bands holding his or her arm at the release point of the throw and isometrically contract for 3 seconds before proceeding to practice unresisted throws.
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