From the RuneScape Wiki, the wiki for all things RuneScape

Dummy

Release date	Unknown edit
Combat level	N/A
Hitpoints	N/A
Slayer level	N/A
Slayer XP	0
Members only?	No
Aggressive?	No
Poisonous?	No
Immune to poison?	N/A
Attack style	N/A
Max hit	N/A
Weakness	N/A
Always drops	N/A
Examine text	I can train on this

Dummies can be found in the building opposite Varrock east bank. It doesn't matter which style of combat you use on dummies, they will only give 5 attack experience per hit. Low level players can train on them until they reach an Attack level of 8.

After this, if they attempt to hit the dummy again, they will receive the message "There is nothing more you can learn from hitting a dummy."

They were used by attack pures with attack levels higher than 8 in RuneScape Classic by using the Wine trick.

Trivia

• There are also Dummies found in the waiting lobby of the minigame Fist of Guthix called "punchbags". Players cannot hit them, even if their Attack is lower than level 8.
• If you attack using a halberd on a dummy in the Combat Training Camp, it will yield the message: "You cannot use ranged attacks on the dummy", even though the halberd is a melee weapon.