Let's cover static contractions. Static refers to lack of movement, but believe me, in static contractions there's a WHOLE lot of stimulus. The ideal time to use a static contractions is when a muscle is working it's hardest, at a sticking point, the top of a movement, or half way. An example would be holding the weight at the top of a dumbell bench press and really squeezing your chest hard and holding that position for 5,10, or more seconds. You could also do it at the half way point of a curl. Or Pull up. Maybe the top of a lateral raise. The posibilities are endless. I like to tack it on to the last rep of a set and follow with a slow negative.
What are the benefits you might be asking? Well, when you force a muscle to stay contracted at its hardest working point, you are forcing it to stay under maximum tension for MUCH longer, forcing more blood into it and spurring gains in strength and muscle growth. Try it yourself. On your last rep of pushups, hold half way up for 10-20 seconds. Hold half way down your last pull up for 10 seconds. Maybe hold half way up your last rep of curls for 10 seconds, or hold that squeeze at the top of a chest fly for 10 seconds on the last rep. Want a real challenge for your shoulders? Hold the dumb bells or cables at the top position for 5 seconds on your last set of lateral raises. It will burn.
And on a similar subject that works perfectly with static contractions, 1 and 1/2 pull-ups. The idea is simple. And the video demonstration is below.(sounds complicated but it's not!) Start at the bottom of a pull up or chin up, pull all the way up, go half way down, pause for 1 second, back to the top, then all the way down. Repeat as needed. And on the last rep, when you go halfway down, pause for 5-10 seconds for a static contraction. AND make sure to use slow negatives. This exercise combines full and partial range of motion, static contraction, and negatives. The massive time under tension will BLAST your back, biceps, and forearms, and give you an IRON grip to boot. Try em!