Volume has been shown to be a decisive factor in your training, particularly in relation to strength and size increases. Volume incorporates -
time or duration covered
Distance covered/weight lifted
The repetitions of an exercise performed
As these tips are in relation to increasing your strength, it is the second and third bullet point which you need to concern yourself with. The way to determine volume is weight lifted x sets x repetitions.
For example, recently I squatted 142.5kg for 4 sets of 8 giving me a volume of 4,560kg.
The weekly volume is also important when it comes making gains. If your weekly volume does not beat that of the previous week then you are not progressing. Simple as.
Volume, coupled with progressive overload are two of the main factors in increasing your strength and size. Don't know much about progressive overload? - Its tip #2 which I will be posting tomorrow!
Whereas volume is the quantitative variable, intensity is the qualitative one. The more work that a person does within a single session, then the more intense that session is. The intensity depends on the load, speed of performance and variation of rest between sets/reps. One point often overlooked about intensity is the psychological effect it can have on a person.
In the case of strength or size gains intensity would depend mainly upon the load utilised in a workout. For example reps at 80% would be a lot more intense than singles at 70%.
Relationship between Volume and Intensity.
As the volume goes up in a workout the intensity should come down, and vice versa. Whichever variable you decide to focus on will have a different effect upon your body's adaptation. Finding the optimal balance of both is a tricky task. Strength athletes could use Prilepin's chart to this end.
To sum up -
Volume is an important factor when it comes to increasing size and strength, however, keep the intensity in check. You would be right to assume upping the weight lifted would lead to an increase in volume, however the effect that this would have upon your CNS could be devastating. Learn to keep them both in check!
Tudor. O . Bompa, PhD - Periodisation - Theory and Methodology of Training