If you are serious, you have a written plan, a book or binder that has your workout already recorded - at least the exercises you are supposed to do. Mine has my own "code" where I will discuss it with Roy ahead of time, and then on one side (right of the page) in parentheses, I record what I am supposed to aim for (weight, sets, reps and rest periods), then on the left side of the page I record what I actually do.
This conversation takes place three times a week based on what he and I just trained that day and how that training went.
It is important, more important than you may realize. If you are not increasing weight, sets or reps every workout, you really are not making progress are you? The human body is amazing at adapting to it's environment so if you do not change things up, it won't need to change to adapt to the surroundings. Don't expect to remember- if you can then you are doing the same thing over and over, I guarantee it!
A timer is also important, to make sure you don't rest too long and you may want to time the amount of time you spend lifting, the "Time Under Tension", the longer the muscle is under tension, the better. It forces you to concentrate, to really think about the tempo and what you are doing.
I also record my weight, how I feel that morning and how I look. It changes, I can look hard and ripped or soft and flabby in a matter of days.
So, some things that I see that are truly a waste of time? I think the number one is using this for their abs:
Yes, I see people come up to this and lean back and quickly jerk their knees up and down a whole bunch of times, I swear, maybe 100 of them! I am sure they are convinced they are building abs of steel, but why don't they get a clue when their abs don't look any better, any tighter, or any different at all? Sure, there is an effective way of very slowly performing leg lifts, but no one does it, no one. And, I hate to be the bearer of bad news, but it doesn't matter what you do, unless you diet long and hard, and get rid of all that body fat, no amount of ab training will help you.
A lot of people spend a great deal of time on this, or something that looks like this: The Ab Crunch
And they are chatting with their friends at the same time! Same thing here, no good, it's just a waste of your time if you don't do it correctly and start the diet first.
I also see people run all around, with no rhyme or reason, training all different body parts. You don't have to train in the bodybuilder style where you train one body part a day, but you do need to consider which muscles you are training and which ones may exhaust from one exercise before you can actually effectively train another. There is actual science behind all this........
Squatting with little weights, I mean really little, like a 45 pound bar, or maybe 65 pounds. The legs and glutes are massive muscles, they need some heavy weight, squatting like this is really a waste of time.
Using the entire body to perform a lat pull down. That's this thing:
The point of this exercise is not how heavy you can go, it's how strict you can do it and isolate the correct muscles, the lats:
If you just pile the machine with lots of weight and then lean waaaaay back to pull it down, you are missing the entire point, you are not utilizing the lats at all. You are supposed to be pulling down with the upper back muscles (lats), not your arms, not your torso, not your entire body.
Lifting weights then launching into a long period of cardio. This is OK if you are trying to lose bodyfat or lose weight (two completely different things folks), or perhaps just participate in "General Physical Fitness" but not if you are trying to add lean mass. It's counter productive.
And last: Doing the exact same thing over time and time again, with the same weights. This has got to be the biggest waste of time. There is no challenge to the mind or body here, muscles will not grow, and you won't lose any bodyfat or weight since your body will be accustomed to the same thing every single time. Might as well stay in and watch a move!
I think that many people seem to forget a fundamental rule about weight training. It takes time, effort and practice to excel. You need to give 100% effort when you are doing it. Just like any skill, you need to learn to be good and you need to put the energy and love into it or you won't reap the rewards. It doesn't happen over night or even in a few weeks.
If you just want to go in and burn off some calories, and don't really care about body composition or sculpting your muscles, then this can be accomplished easily by just jumping rope in your driveway, or any other method of energy expenditure you can think of.
Take a look at what you are doing and make sure you are challenging your body every single day!