Medicham's most notable quality is its great ability, Pure Power, which doubles its otherwise pitiful Attack stat to a monstrous 480. Combine that with a 130 Base Power STAB in Hi Jump Kick and you have a seriously threatening Pokemon on your hands. Its secondary STAB move, Psycho Cut, has decent coverage with Fighting and does not contact the opponent, preventing abilities such as Mummy and Flame Body from triggering. Medicham is most notable for being able to deal serious damage to all of Heracross's counters, meaning it partners well with one of the best Pokemon in UU. Unfortunately, while Medicham has a great Attack stat, the rest of its stats are nothing to write home about; its base 80 Speed and defensive typing are disappointing to say the least. For these reasons, many of its potential sets are outclassed by Heracross and Mienshao, but Medicham still has a niche as a powerful wallbreaker that can rip huge holes in teams if you manage to bring it in safely.
Medicham's best and only viable set in UU uses a Choice Band to boost its high Attack to a ludicrous 720 with an Adamant nature. This gives Medicham the power to break through almost every Pokemon in UU with the right attack. Hi Jump Kick has the most damage potential of any move Medicham carries; at 130 Base Power before STAB, it does heavy damage even to Pokemon that resist it. One needs to be extremely careful about the recoil, however, as an untimely Ghost-type or Protect will send Medicham crashing down. Psycho Cut is a safer move to spam, since Dark types aren't going to be risking coming in on Hi Jump Kick, and a lot of common responses to Fighting-types take heavy damage from it. Most notably, it 2HKOes offensive Trick Room Cofagrigus, and since Psycho Cut does not make contact, Medicham doesn't have to worry about Mummy. Psycho Cut also scores an OHKO on Chandelure and Mismagius, two other threatening Ghost-types, as well as Crobat, which 4x resists Hi Jump Kick.
Medicham's last two slots are for coverage against other Fighting resists, many of which give trouble to other Fighting-types such as Heracross. Ice Punch scores an OHKO on Flying-types, including Gligar, Xatu, and all but the bulkiest of Zapdos after Stealth Rock. A well-predicted Ice Punch can clear the way for a Heracross sweep quite easily, turning the tide of a battle. The last attack is largely personal preference. Trick cripples the Psychic-types that wall Medicham, such as Slowbro and Mew. ThunderPunch 2HKOes Slowbro, but between Regenerator and the dangers of a Choice locked Electric-type attack, it's not always as effective as it could be.Team Options & Additional Comments >>>
Medicham's stats and typing don't allow it to do much else. Choice Scarf works just fine if you need a fast Fighting-type that beats Crobat and Gligar. However, Choice Scarf Medicham is outclassed by Heracross, which can sweep more easily; Mienshao, which is faster and has Regenerator; and Flygon, which has more opportunities to switch in. You could try a Life Orb if you'd like to switch attacks, but it misses out on some key KOs. Fake Out and / or Bullet Punch can be used to give Medicham priority for emergencies. It's important to note that Bullet Punch and Psycho Cut are illegal together, so if you opt to run Bullet Punch, you are stuck with Zen Headbutt for STAB, which makes physical contact with Pokemon such as Cofagrigius. Other options include Bulk Up, Drain Punch, and Recover, but Medicham is simply too frail to take advantage of these moves.
Checks and Counters
Sableye is Medicham's worst nightmare, as it is immune to both of Medicham's STAB attacks. It can survive any one hit from Medicham and cripple it with Will-O-Wisp, which prevents Medicham from doing much of anything. Sableye sometimes even packs its own Trick, so Tricking it a Choice Band doesn't always work. Bulky Psychic-types, such as Cresselia, Uxie, Xatu, and Mew, take little from either of Medicham's STABs. All of them can be EVed to outspeed Choice Band versions, but none like to be Tricked a Choice Band. Xatu also hates elemental punches. Mew can potentially be 2HKOed by Choice Band Hi Jump Kick, but it would have to be very poorly EVed to both be outsped and fall in two hits. The common support Mew can burn Medicham with Will-O-Wisp and then Recover off the damage.
Other than the above Pokemon, Medicham doesn't have any traditional "counters" that can switch into everything it has, but it can be played around with checks. Cofagrigus is a good start, as if Medicham doesn't predict and use Psycho Cut, its ability will be changed to Mummy, and it will become worthless until it switches out. Dusclops can avoid 2HKOs from all of Medicham's attacks thanks to Eviolite. Froslass and Golurk aren't too bulky, but they are immune to Hi Jump Kick. Froslass resists Ice Punch and outspeeds Medicham, while Golurk is immune to ThunderPunch. Chandelure works in a similar vein but usually has to risk losing a Speed tie with Medicham. Bronzong can take any attack other than Hi Jump Kick and KO with Gyro Ball.
Once Medicham locks itself into a move, it is a lot less threatening, as numerous Pokemon can take one of Medicham's attacks, outspeed, and KO with a neutral STAB attack. Additionally, Medicham isn't easy to bring in, so continuous offensive volleys will prevent your opponent from doing so.