Non-specific hypertrophy? I’m not sure what you mean, but you should be using exercises that are targeting musculature specific to your sporting activities, though there were undoubtedly be some general hypertrophy related to this.
If I add muscle to my tris by doing extensions, doesn’t mean it will transfer to my bench. Lifting adds muscle, but if it’s not specific how much does it carry over? Very little from my observations.
Also, using medium to higher reps does not necessitate hypertrophy, just as using lower reps @ a higher intensity (% of 1RM) doesn’t mean you will have less growth necessarily.
It will necessitate non-contractile hypertrophy
Whether or not hypertrophy occurs is vastly dependent upon caloric intake. If you eat excess calories, you will get bigger regardless of your training, though it might not come in the form of muscle for some.
Unless you’re juiced, you can only hold a certain amount of fat free mass without fat gain
Muscle recruitment in weightlifting is marginally increased once going above a certain intensity (approximately 80%, but will vary based on movement, speed of the lift, individual factors, etc.) and the neural efficiency is task related after this. To get a better idea of what I mean by task related, look at what happens once somebody incorporates an exercise they rarely do in their program. Often, they will post numbers that appear to be significantly lower than their other numbers, but within a few sessions or weeks they have increased the lift a dramatic amount. The individual would have become more skilled and efficient in performing the task, but it is unlikely to have any carry-over to other unrelated activities let alone indicate improvement in overall efficiency and motor recruitment.
If neural efficiency doesn’t carry over, why are powerlifters strong as shit in general. If a skinnier elite level powerlifter was going to fight a guy with bigger muscle who doesn’t train, who would you put money on?
The best example I can think of this is looking at anybody deadlifting for the first time. It isn’t uncommon to see >20% improvements (as measured by 1RM in the deadlift) in an untrained or younger athlete within a few weeks of doing the movement if they have never done it before. There are some internet gurus who actually thrive on this phenomenon when training HS kids for 4-6 weeks over the summer and charging out the ass. This improvement is highly unlikely to carry over to any other movements unrelated to the deadlift (esp. dynamic and elastic sporting movements), is not likely to be associated with any dramatic changes in LBM, and more.
All athletes have a transfer period, not just the ones who lift over 85%. Doesn’t have anything to do with being strong.