Its coming knowledge that training was and always will be individual and with that comes a constant evolution of training within the gym, from the golden era to the current day the world of health and fitness has changed dramatically and continues to do so on a daily basis but as always moderation is key so with the good comes the bad and its important to understand which methods and changes are worth investing your time into. regardless of how basic the movement is I always like to question everything and as well as understanding the anatomy of the human body I also take a great amount of time studying machines and how they work with the body.
I feel for people to truly continue moving forwards wether they are a coach or not you have to be open minded or in some ways 'coachable' this opens your mind to new and improved training methodologies that could change the way you train whilst reducing risk of injury. Lets talk Ronnie Coleman for example one of the greats and truly did change the world for bodybuilding however should he have competed in the current day with the new and improved methods he would be in a much better condition for health. You have to learn to adopt the new ideas for you to move forwards and ditch the mindset of 'back in my day' or the 'old school' way. Let the old school be old school and use its benefits for sure but be open minded enough to understand modern ways too.
Lets cover anatomy for the main part of todays post, the wrist joint is not a fixated joint and is capable of a wide range of motion yet when you are in the gym takes a lot of load upon first contact which can lead to some discomfort. The problem with the wrist joint being free moving is the idea that most gym machines are fixated and don't offer the rotation that the wrist needs to efficiently move, By using D-handles you can create and give the movement the wrist needs to move safely through a bicep curl. Should you use a straight bar you are placing a lot more pressure through the joint and onto the bicep which depending on how advanced you are with training may cause discomfort and pain so using the handles allows for a greater range of motion and reduces pain as you are accommodating for the wrist anatomy.
Once you have covered and understood the point I just made you can then begin to apply it to other movements too but again with moderation, I want you to question every movement and understand what you are doing as well as why its going to benefit you, Applying a D-handle to a leg press would be useless and prove no benefits so think before you apply and make sure its relevant to the movement you are doing.