This blog will solely focus on how you should be weight training, as in my experience, most people don't know how or get many aspects wrong. It is also worth noting that this is not a one-size-fits-all approach to training. If you are training with the purpose and goal of an event or to become an expert in a specific subject matter, then your process and style should differ.
In the main, you can focus on three types of weight training: Strength, Endurance and Hypertrophy. Each has its benefits, and your goals and aspirations will depend on which one (or mixture) is the best for you. For a healthy disposition, I will almost always recommend Hypertrophy training.
Before we get into the details of how to train for hypertrophy, it's worth explaining that the makeup of muscles is hugely complex. At a high level, though, they are made up of two types of fibre (fast twitch and slow twitch). Strength training will mainly focus on developing your fast twitch fibres, think sprinters and powerlifters - and will involve fewer but heavier lifts. Endurance training will mainly focus on developing your slow twitch fibres, think marathon runners and grand tour cyclists - and will involve many more lifts at a lighter weight. In the main, you will do these if you are partaking in a specific event or becoming an expert in a particular subject matter.
First, it mainly focuses on muscle size and strength. This can help increase the proportion of lean muscle relative to your other body tissues. Which, in turn, helps reduce body fat and lower waist circumference, which are primary markers linked to avoidable health diseases.
Second, due to the weight and the number of lifts required for hypertrophy training, it makes it the safest form of training leading to the least injuries (it does not avoid injuries altogether, though).
There is excellent research and peer-reviewed science behind what weight to use and the number of reps, sets and rest (see below) you should employ for hypertrophy training. Therefore, implementing the reps, sets, and rest is highly recommended. Regarding the weight, though, this is one of the rare occasions I recommend you use art and not science to determine this.
The scientific way is to work out the maximum amount of weight you can lift for each exercise, then use a percentage (80 - 85%) of that weight. The problems with this are:
Being inexperienced and having a lack of proper equipment, spotter, coach, and warm-up WILL lead to injuries
It is impossible to do for every exercise in your plan
You will continually get stronger all the time, which makes it unfeasible to keep repeating
Instead, use art to determine this over the first two weeks of your training program, starting with light weights and using trial and error to find the perfect one. How will you eventually determine the ideal weight? This is done by focusing on your form, technique, reps, sets and rest:
Form: Concentrate on using only the muscle you are working. If you are doing a bicep curl, you want to isolate and use only the bicep. Avoid swinging, using momentum, gravity or other supporting muscles (like the shoulders and back). Use a mind-muscle connection, meaning you focus solely on the bicep muscle. Think it, see it, feel it.
Technique: Do not let the weight or gravity control you - you control them with a smooth and balanced tempo. Think 1-3-1:
Concentric: One second to move the weight away from gravity
Eccentric: Three seconds to lower the weight working against gravity
Isometric: One second to hold the weight static before the next rep
Reps: This is the total number of times you will perform the exercise consecutively. We should be aiming for a minimum of eight and a maximum of fifteen, with ten to twelve being the sweet spot.
Sets: This is the completion of the total number of reps. One set will equal eight to fifteen reps, and you will complete a minimum of three and no more than four sets.
Rest: This is the quantity of time you will take between each set, which will be no less than sixty seconds and no more than ninety seconds.
In doing this, you will very quickly identify the correct weight to use. You should be able to squeeze out one last rep within the sweet spot of ten to twelve before your form, technique and ultimate inability to lift the weight stops you. You will then be able to use the same weight to complete the same approximate number of reps after you rest before performing the next set. And you will be able to do this consecutively for three to four sets.
Be warned, if you have never trained like this, you will be shocked by how 'light' a weight you will be using. This can be a severe shock to some who 'want to look strong in the gym'. So sorry; check that ego in at the door and get used to heading for those lighter weights.
The good news is, if you consistently do this, you will get stronger and quicker and progress through to heavier weights in a relatively short time. Also, it is uncommon to see proper form and technique in most gyms. So you will get comments and compliments from others on how great yours is.
Finally, it's worth noting that for all the benefits hypertrophy training has, there is a reason it sits at the top of my pyramid. It will have little to no impact in isolation, so you must pay attention to the rest of the pyramid to build a solid base below it. So have a plan, be focused, and, more importantly, know your WHY. It may help to read the following blogs: