More instructors are finding greater merit in random practise/training as compared to blocked...
Random training in golf involves changing one or more elements every time you hit a ball during practice. Examples of this could be chipping balls to the same pin from the same spot but trying to change the ball's trajectory with each swing,... low, medium, then high. On the range, it could be trying to hit different clubs the same distance. Warming up for a round, it could be playing the first three holes of the course from tee-to-green, hitting each shot based on each previous swing's result.
This approach is in stark contrast to Block(ed) practice/training... practicing the same shot (swing, distance, trajectory, etc.) in a repetitive manner from an unchanging lie. Examples of this could be chipping balls to the same pin from the same spot or hitting 155-yard 7-irons for 30 minutes from a driving range mat while only working on the same, single swing change.
Blocked training means breaking things into "blocks" of doing the same thing again and again.
Block practice has long been advocated in many sports and its logic seems more than credible. Repeating a process should help ingrain it and that should help it hold up under the pressure/conditions of competition.
The trouble is that the research does not totally bear this out. While it does seem to ingrain the process in the training environment, (e.g. being able to come back to the range a week later and hit those same 155 yard, 7-irons pretty well), it does not as readily translate well to executing a 7-iron from the rough into an elevated green with a 10 mph headwind during competition.
Obviously, you can't practice a particular 7-iron shot under every set of conditions but you can make the training process more varied (random) and increase the pressure to make it more competition-like. On the range try to hit a high-fade, then immediately follow that by trying to hit a low-draw. Chip to each hole on a practice green where you get a point for getting the ball within 4' of the pin.
Does this mean you should not do any block training? Absolutely not.
If you are working on a singular, specific swing change, block training makes total sense. Developing a smooth-tempo short game swing is probably far better worked on when you take out as many other variables as possible. (editor's note: God knows I've tried).
It is possible to do both types of training simultaneously... something that can be of benefit if your practice time is constrained. There is another advantage to this combined approach. It can be very effective in keeping you engaged avoiding mindlessly hitting ball after ball.
Tiger Woods has said that on the range he takes three or four mindless swings to loosen up and from that point on, he does not make a single swing where he is not trying to work the ball in some manner. So, even if he is working on a swing change that warrants a block-oriented approach, there is a random component to the process.
And if it's good enough for Tiger, it's likely good enough for you.