It is widely accepted that training for pure strength requires a different approach to training for pure mass. A quick glance at the training schedule of an olympic lifter vs that of a bodybuilder will confirm as much. The former will spend a lot of their time working against very high resistances for low reps, whilst the latter will spend more time lifting moderately heavy weights, for high reps with shorter rest periods.
However, whether your main goal is strength or whether your main goal is size there is definite benefit to be had by adopting the training protocols of the other for periods of time during your training.....to sports scientists and strength coaches alike this process is commonly referred to as periodisation.
A lot of strength is developed by fine-tuning your nervous system to activate a greater % of your muscle fibers, in a more co-ordinated manner, in a shorter period of time. These neural adaptions are achieved by working against a very heavy resistance and can be likened to increasing the speed of your broadband internet connection. The improved connection speed between the brain (internet server) and your muscles (computer) allows for greater force (data) output.
Since the resistance must be high for this kind of training to be effective, the reps are forced to be low (you cannot lift something really heavy more than a couple of times!). This in turn means the overall workload placed on the muscles during this style of training is lower as the example below demonstrates.
Workout 1
Our lifter has a bench press 3RM of 100kg and he performs 5 total sets for an overall workout tonnage of 1500kg
Workout 2
By dropping the weight 25kg, our lifter can now perform 6 reps per set (this is a conservative estimate). He performs 5 sets of 6 reps at 75kg for a total workout tonnage of 2250kg
I have used a weight training example for ease of maths but the same principle absolutely applies to bodyweight training. You will create a far greater overall workload doing a high volume workout using classic pull ups versus a workout based around one arm chin up progressions. The sheer difficulty of the latter exercise renders high volume training very tricky indeed.
However, neural improvements is not the only path to increased strength. It is also widely recognised that an increase in the cross-sectional area of a muscle also allows for greater force production and therefore strength gains. This is where the person training purely for strength can benefit from adopting the training tactics of those training for mass. By dropping the resistance, increasing the reps and reducing the rest periods you create an overall increase in the metabolic stress on the muscles.
Greater metabolic stress can help create bigger muscles!
Once muscle hypertrophy has been achieved the person training for strength could revert back to the high resistance, neural training only this time working with muscles that have a larger cross-sectional area and therefore a greater potential for strength production.
And it works both ways....
On the flip side those training for mass can benefit by adopting the tactics of those training for strength. As we have discussed above, getting a muscle to grow is largely based on your ability to put that muscle under greater mechanical and metabolic stress. In other words lifting a moderately heavy weight lots of times in a short space of time.
By spending some time developing your maximal strength you can come back to your high volume workouts and lift an even heavier weight for lots of reps in a short space of time leading to even greater stress and growth stimulus on the muscles.
CONCLUSION
Hopefully you can see from the above examples that whether you are training purely for strength or whether you are training purely for mass there are benefits to be gained by switching your focus to the other side for a period of time.
This is of course why top strength coaches around the world will often structure their athletes training programs to include periods of hypertrophy, max strength and power training. The amount of time spent on each training variable will vary from athlete to athlete depending on their sport and goals.
Even if you are not an athlete and train simply to be strong and healthy you will still likely benefit greatly from mixing up your primary training stimulus on a regular basis. Try it and see.