yep "periodization" that's it. Indeed, form is so key and it took a bit to learn correctly. Yea we would every so often do about 1-2 weeks high rep and definitely random, when needed, and actually not that often. I think we kind of had that effect with low-rep because of all the different variations we would do with low rep and speed days. this makes me want to hit the gym right now.. but i need the good stuff... that's my way to gain muscle while losing fat lol. the good stuff = muscle milk of course!
In brief, a parallel squat is heels on ground, and knees not forward beyond the toes, ass out, upper body leaning forward. A sissy squat requires that you try to maintain as straight a line as possible between your knees and your torso. So the sissy (short for Sisyphus) squat has your heels raised, your body back, and your knees forward beyond your toes. As I noted earlier, they are quite different. The sissy squat approximates a leg extension while also working the hams somewhat. Look for the differences in movement on Youtube. I began doing sissy squats in June, when I changed my routine and at the same time I started doing pistol squats, feeling I should be doing more than one exercise for upper legs. And while the sissy gives a really good quad stretch, among other things, my left knee began to feel a bit wonky. No pain, just...different. I don't know why, but when I stopped them, the wonk went away. And so, I no longer do them. Maybe it's just me.
I've been working out for 28 years, and I have been around long enough and have seen enough youtube videos to know that many lifters (not just beginners) do not know how to squat properly or how to deadlift properly. If one does not have the form down right, one can still get most of the benefit of squats by doing leg presses heavy and all the way. If one does not have the form down right for DL, one can still get a good back by doing chins and t-bar/dumbell rows.
I think there are people here who are far more knowledgeable than I to answer your question. I hope they chime in. As for me, if I am working out in the afternoon, which is usually the case, I try to have a fairly light and nutritious meal a few hours before working out, and make sure I'm well hydrated (mostly water) between that time and the workout. Post workout, my understanding is that it's a good thing to consume about 30 to 50 grams of protein and an equal amount of carbs, preferably within 30 to 60 minutes of a workout, the sooner the better. I've also been led to believe that this is the one time that the carbs can be of a fairly high glycemic index. Even so, I avoid junk as a matter of course. With that in mind, what I have after a workout are a couple of bananas, an apple and a home-made whey protein shake comprising unsweetened, unflavored whey protein isolate powder mixed in skim milk with cocoa baking powder and sweetened with ground stevia root. I then have supper a couple of hours later. Since I sweat a fair amount during the workout, I try to replenish my electolytes afterwards, but I do it with the foods I eat rather than with a sports drink. The bananas have the potassium. I have a small trail mix between my post workout meal and supper, which includes pumpkin seeds, a good source of magnesium. Supper usually has some naturally occurring or slightly added sodium. Since I'm probably doing something wrong here, I wouldn't mind hearing what others have to say.
DLs were never a mainstay of my workout routine, even though I know it is a key exercise. I did them for a while a number of years ago for a full range of motion standing on a shallow pedestal designed for them and, man, DLs are a no-nonsense exercise. I can understand why serious guys do them. At the time, when I added them, it eventually felt like I was overtraining, and I didn't want to either decrease or remove any of the other exercises I was doing. I'm sure that was a mistake. (Although, as with barbell squats, injury is perhaps easier than with most other exercises. Please refer to my "AARP better safe than sorry" principle in an earlier thread. ) Regarding rows, I always did either db or seated pulley rows as part of my back routine until June, when I adopted a bodyweight theme, and decided to limit my pulling exercises (back and biceps) to wide grip pull ups and narrow grip chins, both weighted. I realize it's a compromise, and that rows add thickness while pull ups add width and so on, but at 54 I'm at a point where good enough is good enough. I still go all out, as always, but I don't want to get too caught up in the detail (and volume), even though some of that "detail" is arguably quite important for serious lifters.
As I said, one can get a good back without doing DL. If done incorrectly, DLs can easily ruin one's back. Herniated disks, sprains, strains, among other injuries. If done correctly, DLs can strengthen one's back and even eliminate back pain. Problem is, many don't do DLs correctly. I've seen personal trainers not know how to do them correctly. Blind leading the blind... All the benefits of deadlifts won't matter if one is laid up with an injured back.
DL are a great compound exercise, and I do them, but I just don't feel comfortable about going all out. Some guys do max weight with just 4-6 reps, and while I do that with everything else, I have seen enough injuries in my time to know that one sloppy mistake can do tremendous damage. I'll go heavy on back when it comes to lat pulldowns, dumbbell rows, T-bar rows (with back protection), and weighed hyperextensions. But with DL, I go higher reps. Call me chicken, but I'd rather be chicken than laid up with major back problems. And, yes, all it takes is one stupid mistake. I'm going on 44, and I take pride in keeping in top shape these last 28 years injury free (other than tendonitis and a back strain I received when I was squatting and lost control of the weight). I am not going to risk serious injury at this point. I'd like to be lifting regularly when I hit your age.