It's also a chance to get a little silly, as evidenced by the frocks, wigs and dolls in pouches that some competitors took with them while passing confused farm livestock on the run last year.
This year's Mud Muster offers a 3km "Give it a Go" beginners' course, as well as continuing the 5km (one lap) and 10km (two lap) options.
The challenges on the Tyrone farm in the Turakina Valley will include rugged hills, ponds and streams, vertical wall climb, muddy cargo net crawl, a "slip and slide" and, of course, plenty of mud.
Entries are open to all adults, and secondary school students aged Year 9 and over.
You can enter individually or as part of a team.
Local businesses are also encouraged to throw their hat into the ring for some workplace team building.
"Sport Wanganui will be providing a series of early-morning group training sessions for those keen to get in shape and prepare for the big day," said a press release.
On the day, an electronic timing system will record everyone's completed course time, which will allow many to compare their 2013 efforts, while prizes will be given for the top three in each category for the more competitive athletes.
All participants will go in a draw for spot prizes and receive a complimentary treat when crossing the finish line, while 5-10km runners will get a race pack.
The 2014 McDonald's Mud Muster is on October 18, with early-bird entry prices at $15 for students and $20 for adults doing the "Give it a Go" course.
Entry for the 5-10km courses is $20 student, $35 adult.
Included in the ticket price is transport by Transit Coachlines to and from the venue, while limited car parks are available for a fee.
Register online at www.sportsground.co.nz/mudmuster, or visit the Sport Wanganui website (www.sportwanganui.co.nz) and Facebook page for more information and photos from last year.