Its legs freely stretch and contract. Using these springlike limbs, it bowls over foes with devastating kicks. After battle, it rubs down its tired legs.
Rocket Jump Kick (and Dragon Kick once mega'd) provide the STAB backbone for this hyper-offensive lead set. No Guard on the mega allows the use of Rocket Jump Kick for the extra power without worry of the insane recoil. Hi Jump Kick could also be used for primary STAB if you desire more consistency without the mega. Hitmonlee gets a pretty great range of coverage, being able to slot in options for just about any team composition. However, Seismic Kick's chance to lower defense and Blaze Kick's burn chance are the most helpful to shore up Hitmonlee's low defenses, cripple walls, and further help its high attack stat.
Hitmonite makes the most sense to use here, as Hitmonlee is probably the best Hitmon to use it with. A lack of recovery hurts it, but the coverage and power of its moves can help it make as much impact as possible while on the field. If not using the mega, an Apex Orb can help Hitmonlee out by giving it a bit of passive healing and evasion boost that it desperately needs.
Hitmonlee's biggest weakness is its frailty. Bulky Physical walls who resist or are unaffected by fighting types can easily set up or stall in its face, and Ghost-types switching into a Rocket/Hi Jump Kick can put Hitmonlee well into KO range, if not make Hitmonlee KO itself outright; especially if it has been hit before or if hazards are up. Hitmonlee is definitely a lower-tier mon, but can be used with or without a mega stone depending on team composition.