The parallel front squat is an abbreviated front squat, used to strengthen the sticking point of the front squat and clean in particular.
 
 
Execution
 
Perform a front squat, but stop the descent of each rep with the thighs horizontal.
 
For a lot more information on the execution of the front squat, and squat in general, see the following articles:

• The Olympic Weightlifting Squat
• Proper Foot Position in the Squat
• Squat Stance & the Olympic Lifts
• Squatting, Valgus Knees, The Knees-Out Cue & Facebook Coaches

 
 
Notes
 
This variation places more strain on the knees than full-depth squats, so only use it if you have healthy knees and plan to take care of yourself.
 
 
Purpose
 
The parallel front squat forces the lifter to stop and change directions at the most mechanically disadvantaged point in the movement, where the leverage is the worst. This will build strength in this position, which can help lifters improve their ability to drive through the sticking points of their cleans and squats. It is a more direct approach for improving problems driving through the sticking point of clean recoveries than the parallel back squat.
 
 
Programming
 
There are a number of possibilities when it comes to programming the parallel front squat. Most common will be sets of 3-6 reps and using this variation as one of 2-3 or more squat sessions each week. It can also be used for back-off sets following sets of full-depth front squats.  
 
 
 
Variations
 
The parallel front squat can be performed as a pause squat or with prescribed tempos (usually slow eccentric movement).