Exercise intensity/load: does it matter?

In a weekly training group I lead, we try and have a focus each week – technique, load, helping others, etc. I noticed that when we were looking at the load, all athletes underestimated their strength, which I’m sure is something you’ve noticed when you’re training with a trainer – you can lift a lot more than you thought!


Me:  I want you to do 3 sets of 10 repetitions, and select a weight you can do 10-12 reps, stopping at 10.

Everyone: No problem (all do 10 reps)

*a week later*.

Me: I want you to do 4 sets of 8 reps, select a weight you can do 8-10 reps with.

Everyone: No problem (all do 10 reps)

Me: …but let me know when you are on your last set for an exercise and I will come over and tell you when to stop.

Interestingly, the last set of 8 turned into 25-30 reps!

So, does the load matter? No, no, no, no….but yes! Let me explain.


The load matters based on your goal. If we look at the repetition chart below, working at varying intensities helps create a different response in the muscles.

The adaptations you get from training are specific to the load used/repetitions performed

Strength Training – strength is improved due to an improved ability to fire motor units in a coordinated effort and a better ability to fire these motor units.

Power – ability to transform physical energy into a force, the person who moves the same weight quicker is more powerful. Based on motor unit recruitment and adenosine triphosphate (ATP)

Hypertrophy – an adaptation to using the correct loads to stimulate an increase in the size of a muscle cell over time this is chronic hypertrophy. An increases in the number of muscle cells and therefore result in an increase in muscle size in hyperplasia. The short term increase in muscle size directly after training a muscle is the  ‘pump’ due to an increased blood flow to the muscle.

The important point is that you need to be near to failure on your last repetition, to get the response you are after, as this is thought to activate and recruit a greater number of motor units in the muscles. As you reach your target repetition range, more motor units are recruited. This type of training is good to increase the exercise-induced metabolic stress on the body required for hypertrophy. The negative side is that it can also lead to overtraining. This is where you need to consider a periodised plan where you go to failure for several weeks, followed by a de-load week to allow the body to recover. Performing a set to failure (10 reps) has been reported to increase the levels of growth hormone when compared to the same load not to failure.

However, there are many more variables to consider  – time under tension, rest intervals, volume to name a few which can be another blog on their own!

The important thing to consider is no matter what weight you pick, you complete as many repetitions as you can. This means the muscle is recruiting as many motor units as possible, this will then lead to adaptations as the muscles has been stressed enough.

Considerations to the effects of training to failure regularly (fatigue): if you are in-season for your sport, you may want to have a slightly lighter weight but still only perform the number of repetitions for your goal. For example, if your target is 5 repetitions select a weight you can get 6-7 repetitions with but stop at 5.

The chart on the right is a great tool to use. If you are going for max exertion and trying to recruit as many motor units you use the absolute load. For example, 75% 1RM for 10 reps; if I was going for near maximal exertion, I would use a load of 73% 1RM for 10 repetitions.


Going back to the load, does it matter?

No, if you are not training for anything specifically and go to the gym for fun/health. Pick a weight and do a many repetition as you can

Yes, it does if you have a specific goal, although you still need to be within a certain rep range to get the goals you are after.