Melee is the mode of combat where belligerents engage in close range body-to-body skirmishes. It can be done either armed or unarmed, and is favored by tributes who rely on brute physical strength to overpower their adversaries, more so than anything else they have at their disposal. This is because tributes that employ this tactic generally find it most effective to best their targets within arm's reach. As such, those that fight by melee tend to be very direct and confrontational while in the arena - always the first to close the distance between them and enemy tributes, taking down designated targets head-on.
For this reason, melee-style combat is ideal for tributes with reasonable physical prowess and aptitude for brawling.
There can be many reasons for tributes to rely on melee combat, either they favour it as a primary battle technique or they were forced into it since they couldn't get their hands at a weapon at the initial Cornucopia bloodbath.
Advantages and Disadvantages
Advantages of melee include being able to master anti-personnel close combat techniques and are probably the most well-balanced in this regard in terms of offence and defense. Of course, whatever performance they make in the arena and how well they fare still all depends on their natural aptitude for fighting, along with adaptability in combat and overall luck; not to mention how good was the training that tributes received prior to the competition. However, this approach is not without weaknesses. The most obvious would be that because the tribute in question must get close enough to dispatch the target(s), he or she could be thwarted by simply keeping the distance solid between the attacker(s) and the target(s) -- usually by relying on ranged combat, hit-and-run tactics, or even by hiding from or outpacing the pursuer(s). Tributes who use this approach are also vulnerable to traps and ambushes.