Do Trunk & Leg Position Effect Patellofemoral Joint Stress During the Forward Lunge?


The forward lunge is a common lower extremity exercise prescribed in both the fitness as well as rehab setting. While variables such as trunk and leg position affect the force (or stress) placed on the lower extremity (e.g. at the patellofemoral joint – PFJ), MOST research has been performed with respect to the lead (or forward) limb. Knowing how trunk AND leg position affects loading at the PFJ is important because overuse/overloading has been shown to be a causative factor of PFJ pain.

Study Objective

To describe patellofemoral joint (PFJ) forces on lead AND trail limbs during 3 variations of the forward lunge exercise


PFJ forces were measured for 18 persons (5 females, 13 males) who performed the forward lunge with either:

  • A vertical trunk AND vertical lead limb (VV)
  • A flexed trunk AND vertical lead limb (FV)
  • A flexed trunk AND flexed lead limb (FF)


 The following study found that PFJ forces (affecting the trail limb) are GREATEST with a vertical trunk AND vertical lead limb followed by a flexed trunk AND vertical lead limb. While PFJ forces (affecting the trail limb) were LOWEST with a flexed trunk AND flexed lead limb, it should be kept in consideration that this condition produced the GREATEST PFJ forces on the lead limb.


Take Home Message & Practical Application

One concern with the forward lunge is preventing excessive forces on the lead limb. The most common cue to prevent this is to not let the knee go past the toe when lunging on the forward limb, BUT little attention is paid to preventing those same excessive forces on the trail limb. The following study demonstrated that PFJ forces vary based on trunk AND forward leg position. Thus, when designing an exercise program that involves the forward lunge, variation as to trunk and leg position SHOULD be kept in mind to prevent overuse/overloading at the PFJ of both the lead and trail limb. To wrap things up, let’s take a look at what those variations look like as well as ways to progress the forward lunge exercise!


This article comes from the DPT Students of EvidenceBasedMvmt.



  1. Hofmann et al (2017). Trunk / Shank Position Influences Patellofemoral Joint Stress in the Lead / Trail Limbs During the Forward Lunge Exercise. Journal of Orthopedic & Sports Physical Therapy, 47, 31 – 40.

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