Full Range of motion and locking out.
Full range of motion is very important for growth & strength, if you only train with a short or half rep you will only build strength within the range you are training.
A major aim of weight training is to make our life easier by being able to lift & move things in everyday life that most people can’t. Take a squat for example; if you only go a quarter of the way down (Femur above parallel) you will only be strong to that quarter rep. All of a sudden one day you have to squat down low to pick up something heavy & you have limited strength & will struggle to pick it up. So, with this explanation you can see why it is important to use full range.
BUT, there becomes a point of DIMINISHING RETURNS if you go too far.
Now in the case of the overhead tricep extension, I use full range when warming up with light weights. I concentrate on flexing the muscle all the way through the contraction, particularly at the stretch position. This is to make sure that the weight is being held by the muscle & not the ligaments & tendons. Once I reach my heavy weight for sets I stop going to full stretch so as to avoid over stretching & injuring my ligaments & tendons. The distance between full stretch & where I stop may only be 3-4cm so I am still working through enough of a range to create a stimulus for training but greatly decreasing the chance of injury. Take a standing barbell curl, I never let my elbow joint go straight at the bottom of the rep but rather hold the weight about 2 cm off full extension. This allows me to keep the muscle under tension & avoid the stretch on my tendons when under heavy weight.
The amount of weight used coupled with range of motion versus the possibility of injury. This yields diminishing returns & something to think about when your training partner tells you to go deeper in a dumbbell chest fly or parallel bar dips. Of course each person will differ in what range they can handle. Arnold used to be able to get the dumbbells to touch floor when he has doing a chest fly but it would be interesting to ask him how his shoulder joints are now.
Similarly, the lockout. We sometimes lockout to get the best contraction we can in a tricep extension. But at what cost? I see people all the time locking out their elbows on this exercise, bench press, shoulder press etc. Your joint does not have to be locked out to get the best contraction. There is no need to lock out unless you are training for powerlifting where this is an essential part of the movement. If you want the best contraction at the end of your rep concentrate on squeezing the hell out of the muscle you are working instead. You will get a great pump & save your joints.
Next time you’re training, concentrate on the mind muscle connection for the best contraction & lift smart for longevity in the sport.