Bulletproofbodies spent an entire year training for HYROX.

This is what we learned:

Hyrox is a HYBRID sporting challenge that interrupts 8 km of Running  every 1 km with a FUNCTIONAL MOVEMENT EXERCISE.

Ski Erg

Sled Push

Sled Pull

Burpee Broad Jumps

Rower

Farmer’s Carry

Weighted Lunges

Wall Balls

The Runs are compromised by the fact you are fatigued from the Functional Exercises.

Hyrox is predominantly a Running race, if you do not consider yourself a runner, then you have some work to do.

As consequence, you are vulnerable to the same injuries runners get.

Known predictors of lower extremity injury include running greater than 40 miles per week and previous lower extremity injury.

As Hyrox does not require you to run more than 1 km, this significantly lowers your risk of injury as you are not running continuously.

Previous injury is the biggest predictor of new injury.

While training errors lead to the majority of running injuries, biomechanical factors, such as foot insufficiency, muscle weakness, genu varum, and high Q-angle, contribute to 40% of running injuries. (Lysholm J, Wiklander J. Injuries in runners. Am J Sports Med. 1987;15:168-171) [PubMed] [Google Scholar] [Ref list]

A recent systematic review of the incidence of leg injuries among long-distance runners found that most injuries involve the knee (7.2%-50%), lower leg (9%-32.2%), foot (5.7%-39.3%), or thigh (3.4%-38.1%)

Chronic exertional compartment syndrome, tibial stress fractures, posteromedial tibial stress syndrome, popliteal artery entrapment syndrome, gastrocnemius-soleus strains/tears, and Achilles tendinopathy are common running ailments.

These are:

Knee pain

Calf pain

Achilles tendinopathy

Plantar Fascia Pain  

The most common injury associated with Hyrox is ITB related hip and knee pain. Combined with tight rectus femoris (Quad that also flexes the hip)

The other thing about Hyrox is that you are likely to lose muscle as it pays to be lighter in order to run faster. This is why it is important to maintain your strength training and not just your endurance.