There are 51 Trophies that can be collected.

Bronze

Getting to know your new Heroes    
Buy the 2nd Level in MUD World Tour    

Flaming Wheels    
Buy the 5th Level in MUD World Tour    

Dynamite Fuel    
Buy the 9th Level in MUD World Tour    

MUD Princess    
Buy the 13th Level in MUD World Tour    

Four Heroes, one Champion!    
Win the Monster Energy FIM MXoN Event in MUD World Tour

After me the deluge!    
Win all the events of at least one Level in MUD World Tour

He definitely has talent!    
Complete a race with a Hero with the right Talent for that Event in MUD World Tour    

Is he your favourite?    
Reach 5 points in one of your Hero Skills in MUD World Tour    

Thirst for Resistance    
Buy all the Energy Drink Cards in MUD World Tour    

Gilded Crew    
Accomplish your Heroes' Team Target 20 times in MUD World Tour

A Hard Race Night    
Complete a hard Quick Race of 7 minutes + 2 laps in MUD World Tour    

What a Record!    
Pass through 45 Checkpoints in the same Checkpoint Race in MUD World Tour    

Eager for Checkpoints    
Pass through a total amount of 250 Checkpoints in MUD World Tour

The Gladiator    
Visit one of the available Arenas in MUD World Tour    

You are a Tricky Guy    
Buy all the Trick Cards in MUD World Tour    

The guys love me    
Accomplish your Heroes' Trick Crew Target 10 times in MUD World Tour

Easy as falling off a log    
Win a Quick Race in Official Mode    

Let them eat dust    
Stay in first position from the Holeshot to the end of a Championship Race in Official Mode    

You like it different!    
Customise a Championship in Official Mode    

First Round    
Beat Cairoli in the first race of a Championship in Official Mode

Three is better than one    
Finish in one of the first 3 positions in the first 3 Races of a Championship in Official Mode    

Hit the Rock    
Beat Roczen in a Championship in Official Mode

Ride hard or ride home!    
Win a Quick Race in Multiplayer    

Points to count    
Earn 450 experience points in a Quick Race in Multiplayer    

A man, a nation    
Win a Monster Energy FIM MXoN in Multiplayer    

I love my Connection!    
Take part in 20 races in Multiplayer

Raising to the top!    
Reach Level 20 in Multiplayer

Be the Host!    
Create a Lobby and Start a race!    

Saving the Best Moments    
Enter for the first time in Photo Mode Camera of any game mode.

Scrub Around    
Perform 30 Scrubs in any Game Mode!    

Faster than light!    
Do 15 Holeshots in any Game Mode!    

Is that your heaven spot?    
Select the same gate number 5 times on different tracks    

Do NOT like the ground!    
Finish in one of the first three positions without falling in Official Mode    

Take a course of MUD    
Fall a total of 10 times in a race in any Game Mode    

Firestarter    
Do 25 Burning Starts in any Game Mode!

Silver

The four MUDsketeers.    
Win all the events of at least one Level with all your Heroes in MUD World Tour

Enough??    
Win all the events of all the Levels in MUD World Tour

Fashion Victim    
Unlock all helmets in MUD World Tour    

The Team Check List    
Unlock all MX1 Teams in MUD World Tour

It is NOT his Achilles' heel!    
Reach the top (10 points) in one of your Hero Skills in MUD World Tour

Homeboy    
Complete a Monster Energy FIM MXoN race in Official Mode

The conquest of the throne!    
Win an MX1 Official Championship in Official Mode

Multiplayer Maniac    
Complete 100 races in Multiplayer

Someone is getting better    
Reach Level 50 in Multiplayer

Know 'em all    
Complete at least one race on all 12 Official Tracks in any Game Mode

Gold

The Collector    
Buy all Levels, Events and Heroes in MUD World Tour

Race again, and again!    
Complete 150 races in any Game Mode apart from Qualifying Mode

Platinum

Owned    
Unlock all Trophies

3 Secret

http://www.ps3trophies.org/game/mud-fim-motocross-world-championship/trophies/