There's nothing stopping him from keeping up the speed at 29. It's not like he'd be some decrepit old geezer in 2028. Provided he's well rested/utilised, and has access to top of the field physios and doctors.
I don't think a guy wins 5+ tournaments in a year just spamming speed bursts and first attacks. His game is multidimensional, there's the serve deception, there's the huge pressure on the opponents to keep it short, there's his short game which is arguably the best in the game, there's the angles he uses, there's the quick and decisive first attack, there's the low arcing spinny drives that dip and evade his opponents, there's the ability to dictate the rallies, There's his hugely underrated receive ability - opponents almost almost win less than 50% of their serves against him, seen many of the big players win as low as 30 - 35% of their serves, and I think this is where most of their woes start actually.
He's easily won 15+ tournaments in the last 3-4 years. Definitely not a one or two trick pony.
