I'd say that Naruto's very persistent as far as having the drive to go after his dream of becoming hokage but I wouldn't say that he's more of a hard worker than all the other nins. Compared to the others he may train just as hard as everyonelse with a few exceptions. Now Lee is a true genius of hard work. Naruto's also has a "cushion" (kyubi chakra) so to me, he doesn't really have to work as hard as the others.
Yes he does/did train a lot
Training Naruto Was Involved In:
Training For Genin Exam I think Naruto is the only one in his team that actually trained the night before the Genin Exam with Kakashi. Naruto did situps, several muscle exercises and beat up a plush look-alike of Kakashi.
Climbing Trees - When Kakashi knew Naruto, Sakura and Sasuke didn’t have much experience with Chakra, Kakashi made them climb giant trees to help with their chakra development. It took Naruto a few days to get on top of the tree without falling but he did it. Thanks to angered motivation from Sasuke, he learned better control with his Chakra through this exercise.
Training For Chunnin Exam Final Tournament With Pervert Sennin - When Naruto was training for his fight with Neji in the Chunnin Exam Finals, he met Pervert Sennin. Pervert Sennin taught Naruto a few new things about Chakra control, he also taught him how to use Summoning No Jutsu. (Which came in handy in Naruto’s final battle with Gaara)
Training With Pervert-Sennin to learn the Rasegan Jutsu This training required Naruto to use his mind. It took a lot of steps to learn this Jutsu and each step was harder than the last. It’s an advanced Jutsu that allows Naruto to send people flying with his Chakra. It took Naruto a lot of patience and stress but he has successfully mastered this jutsu
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Sasuke
Training Style
Sasuke is the very opposite of Naruto. His dark soul pushes him into new heights. His passions for killing his brother, Itachi, makes him train hard. Sasuke isn’t shown training that much in the series but it is known he has gone through extensive training and he is very powerful for his age.
Training Sasuke Was Involved In (Shown In The Series):
Climbing Trees - Like Naruto, Sasuke had to climb trees in order to balance his Chakra better. Sasuke pushed himself to climb trees faster than Naruto. Sasuke took breaks during his training while Naruto went training non-stop. Even so, he completed climbing the giant tree the same time Naruto did. After this training, he became stronger and that was shown when he had his fight with Haku.
Training For Chunnin Exam Final Tournament With Kakashi…TO MASTER THE CHIDORI TECHNIQUE! - When Orochimaru was after Sasuke with a passion, Kakashi taught Sasuke how to perform the “Chidori” (Also Called Lighting Edge) Jutsu. The Chidori technique requires several precise hand seals as well as a great deal of Chakra focus. It has the power to pull things into oblivion, as well as light things on fire. It took lots of hardwork but thanks to Kakashi, Sasuke mastered the Chidori Jutsu.
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Neji
Training Style
Neji is without a doubt, a dedicated individual. In the manga, he’s shown training a lot. He usually trains outside, practicing the Byukugan or other new techniques he wishes to use in battle.
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Rock Lee
Training Style
The most dedicated trainer in the series! Rock Lee is always training in his spare time and he only desires to become as strong as his idol, Gai. Rock Lee is known for an obsession with training, and Rock Lee always sets goals for himself. (Example: “If I can do 200 pushups, Sakura will like me!”) Rock Lee always improves his strength and skills with his training and that makes him a force to reckon with.