Using a kettlebell while sitting at my desk to do occasional shoulder presses over the course of a few hours, I wonder if there's any benefit or am I just risking injury? What volume would I have to work with in order to see any positive benefit? For simplicity's sake, let's say I am not doing any other kind of training. The load is a 5 or 6 on the RPE scale.
What volume would I have to work with in order to see any positive benefit?
If you are going to incorporate an exercise into a frequent daily routine then you need it to be very low volume, otherwise you will over stress your body without giving it time to recover and build muscle. This concept of low-volume exercises throughout the day is called "greasing the groove."
For simplicity's sake, let's say I am not doing any other kind of training.
Focusing on doing a single isolation exercise, while not training any other muscle group, is a surefire way to create muscle imbalances and get injured.
From what you've described, I see two options:
- Start doing full-body workouts one - three times per week to help balance out your current shoulder isolation routine.
- Replace the shoulder press with a healthier compound workout that won't cause any muscle imbalances. In other words, SQUAT. Squats are called the grandfather of all exercises, and are considered to be the single best exercise you can do.
If I understand your question, you could look at it a little more basically and ask:
Is someone who's doing a bit more physical work during the day going to have better strength than someone who doesn't?
If you hopped up from your desk and tried to 1RM a deadlift after sitting on your butt for a couple of hours, that would probably be a bad idea.
But doing activity that doesn't require a warmup instead of just not doing it would be a great idea. In my office I have a TRX-knock-off suspension trainer hanging from the door and an ab wheel in the corner. It's not scientifically programmed strength training, but if I did it sans-other-training it would still be a workload that my body would have to adapt to (a.k.a. strength gain).
The amount of gain would obviously be minimal, but it would be there. To argue that it wouldn't would be to somehow suspend the general adaptation syndrome.
As part of a larger athletic program, it's related to the 23/1 rule, whereby people get very serious about their 1 hour of training per day and spend the other 23 in a sedentary lifestyle.
The line in the sand for when this would be a bad idea is when you're lifting a weight that requires a warmup, or if the chair isn't stable enough to allow you to lift safely.