Originally Posted by NLBwell
If the poly is giving you 80 hours before it breaks and you don't mind dead poly for your arm or the decreased performance, sticking with the poly is fine - I myself wouldn't do it because of arm worries.
I like kevlar stringbeds and have tried most of the pre-packaged sets with the syngut crosses. They last a long time and perform well if you are used to them. I really like ToughGut crosses at higher expense, but more comfortable and more feel, spin, and power. I wore through the kevlar before the gut broke.
Also, I don't understand why people think 100+ hours a week is outrageous. If you don't have a job and you want to improve, why would you practice less than 4 hours per day? (You are not a kid worried about damages to growing joints or old enough to not be able to play that much and stay healthy) When my college roommate and I graduated college and didn't yet have jobs we practiced 8 to 12 hours per day. (Of course,not having jobs, we didn't have much money)
Because there is a point of limited returns at any age. Academy kids don't even put in that many hours. The longer you put in on the court, the more you put your body through. As I'm sure you're well aware, you need to give your body a chance to recover if you want to get better. If you're constantly building muscle and increasing flexibility, going hard 4 hours a day, every day for a year is not maximizing what your body can give you. You're going to need an off day or two, and even then, all that time should not be spent playing tennis. As nyc rightly said, some of that has to be off-court training: agility, plyometrics, endurance, etc. If I didn't need to work and/or go to school, AND I always had a good hitting partner AND I had the money to do it, I would be damn sure that by this time next year, I would be troubling 5.0s. I would fix my strokes, fix my serve, increase my fitness level, everything. But now I'm getting off topic
But to the OP, as now a few of us have said, if you're really serious about this, then you're going to need to invest in your improvement. I didn't even see that phoenix mentioned practicing with dead balls when I'd mentioned it, but he is right. It's much the same.