I’m not gonna lie, I’m not an expert in training swimmers. I worked with only one in my 23 years career.
I am not the best person to ask for advice in that regard.
HOWEVER one thing that I can tell you is that most people who want to train for a sport, regardless of the sport, jump into sport-specific training way too early. The initial focus should be to become strong in the basic movement patterns.
Sport-specific work is an easy sell to athletes because the brain instinctively assumes that doing exercises that look like your sport will automatically improve performance faster than general exercises. That is not exactly the case. I prefer to see “sport specific” exercises as “transfer” movements.
Essentially their purpose is to take the strength and power that you have and train you to apply them in a movement pattern resembling your sporting action, allowing you to then transfer those capacities to the skill itself.
It looks like this:
Just for the sake of understanding, strength transfer exercises refer to lifting movements where you train the specific range of motion required in your sport and power transfer exercises are explosive movements sharing technical similarities with your sport skill.
if you are limited in your capacity in a category, the category to the right will be limited in its potential improvement.
For example, if you lack overall muscular strength, your capacity to produce power (Power = Force x Velocity, if you can’t produce force you will limit your power potential). Not to mention that stronger muscles also normally have a stronger stretch reflex (we saw earlier why that is important).
By the same token, if you have a weak muscle this issue might make it hard to effectively and safely increase your strength in the big basic lifts. If you can’t improve on the big basic lifts you will limited in your capacity to get stronger, which will limit how much power you can generate.
If you never focus on developing general strength (and muscle mass, since having sufficient muscle mass is required to optimize your strength), you can do all the specific work in the world, improvements will be limited. Plus, having weaker muscles means that high speed movements will be more dangerous and more likely to lead to injuries. When you produce a lot of speed, you must decelerate it. Stronger muscles are better at decelerating. If you have weaker muscles, the tendons, ligaments and structure will absorb more of the force when having to decelerate.