I've been asked a few times in the past "how much weight should I add each week?" by people who have read "personal trainer" articles online. I say "personal trainer"... I mean an individual who usually work in the gym, buys Men's Health every week and now thinks he's ready to train Cristiano Ronaldo...
So to clear this up... you simply can't answer that question. Everyone is different for a huge number of reasons (of which we'll go through a few below). In my opinion, it shows a serious lack of knowledge for someone to think you can tar everyone with the same brush and standardise the level of progressions in someone's training programme! One of the first and most important steps of programme design is SPECIFICITY... I learnt that in GCSE P.E! How can you be specific to someones goals if you're prescribing a 16 year old kid who's walked into a gym for the first time, the same level of progression as an elite athlete who's been training for 20 years! This article "guarantees" you to add 90lbs to your lifts in 9 weeks... (impressive if you can only squat 40lbs when you start...).
If it was as simple as increasing load by 5% a week.. the 100m WR would be under a second by now!!
Anyway, rant over. Here's my reasoning for hating the 90% of PT's described above. There is not one single answer, but a combination of some of the points below:
Exercise learning/neurological adaptations
This is the most obvious explanation for rapid "gains" at the start of a programme, mainly from people new to exercise in general but a lot of people can fall into this category. I've been a PT for 8/9 years and worked in professional football for the last 4 years, but I only added olympic lifts into my programme last year. Having not yet done any formal courses on this type of training, I've had to teach myself the exercises and movements. Technique is obviously going to get better with time. Imagine if I had started with a 40kg back squat to learn the movement and increased by say 2% a week (as some forums are suggesting). After 6 weeks I'd be squatting 45kg... whereas in reality after becoming more familiar with the technique I would probably double my initial load because I'd have started light to learn the movement. Adaptations to training are specific to the type of training performed. For example aerobic training will have minimal effects (if any) on muscular strength or size. Different types of training effect the body in different ways. This is a basic concept but stick to the basics and you can't go wrong, right?
Short term response to stimuli
You will make the quickest gains in the first phase of a new programme. This is while the body adapts to a change in routine. Eventually your progress will begin to slow down. The key to making continual improvements is to avoid, or limit the time at a level of plateau (as shown in the high-tech graph below). This is where you get to a state where you are not improving and progress stops. To avoid this, you must change your programme to keep improving. Everyone will hit this at different times, yet another reason you can not simply throw out a figure of how much weight to add every week!
Daily differences
Some days you feel like sh*t right? Well if you feel lethargic and fatigued, you're not going to want to add 30% to last week's deadlift PB! We differ week to week, day to day, that's just human nature. As I touched on earlier, if you could constantly improve regularly, week on week... then either you aren't working at the correct intensity; or you're superman (what a way to find out, congrats!). Sometimes you'll hit a PB (PR if you're a Trump loving American...), and then you might go another two weeks and not be able to hit that weight. There are so many variables that will affect this, it's impossible to control them all! Nutrition, sleep, hydration, fatigue, mood, time of day... all sorts!
Conclusion
There really is no straight line answer to how much weight you should add each week. There are a lot more factors that would affect your progress, far too many to write about in a single blog post... coaches have been working years to get as close to the answer as possible... it's a never ending circle! The best piece of advice I could give you is to simple go off how it feels on the day. If you can easily reach 10 reps, try the next weight up. If you can't, either stick to the same weight/reps or add a few more reps in or an extra set; any progress is good progress - if you are regressing, change up your programme or get in touch with an S&C coach to help you out. And next time your PT says "next week we're adding an extra 20kg plate" tell him to piss off!!
Enjoy this article? Please let me know below! Are you a PT I described? I would LOVE to hear from you too!! :-)