Any pain that occurs while training hard and racing well can create concern or worry. But, identifying the problem and properly managing the issue can make the difference between a successful season and an ongoing frustrating or nagging injury. I had a patient this past weekend that ran a fantastic race to open up their season. However, the day following, they could barely walk without significant pain on the top outside edge of their foot, especially when pushing off. After checking their lateral ankle/foot muscles, especially the peroneals (which were fairly tight and tender), and the relative bones/joints (the calcaneocuboid and talonavicular had restrictions, with significant pain over the cuboid bone), it was evident that the patient was experiencing Cuboid Syndrome. So what is the cuboid and why does this type of pain pattern occur? The cuboid is the outer most bone in the foot that gives the lateral portion of the arch its stability. The cuboid is fascinating in that it has articulations with 3 different joints of the foot, is secured in place by 7 different ligaments, and its position is determined by the relative position of the peroneus longus, an extrinsic foot muscle (which means it has attachments outside of the foot complex) whose tendon passes through a groove on the outer edge of the bone. Normally, this bone glides acting as a pulley to increase the mechanical advantage of the peroneus longus, which contracts to increase the stability of the forefoot from midstance to toe-off as the foot pronates. However, often times (especially when fatigued) the foot overpronates creating hypermobility in the arch. This gives an additional advantage to the overworking peroneus longus, allowing it to pull with more force, enough of which can pull the cuboid out of position. Cuboid Syndrome refers to pain over the cuboid as a result of this mechanism. Sometimes it can occur as a result of a traumatic injury, such as an inversion sprain, and sometimes it can occur following overuse, such as what my patient experienced. But, the symptom pattern is very similar. Pain is typically directly over the cuboid and can refer to the medial arch and 4th metatarsal. Pain usually occurs during toe-off that can result in weakness with propulsion. It is typically very painful when weight-bearing, but can also be painful with non-weight-bearing ankle motion. If you suspect your cuboid might be the issue, the next question is probably: what can I do for it? Cuboid Syndrome responds particularly well to cuboid manipulation. Patients typically notice a significant decrease in pain following the adjustment. But, the adjustment is only one part to the resolution. The tight soft tissue structures must also be addressed (namely, the peroneals, toe extensors, and tricep surae group). Additionally, the foot intrinsics should be strengthened and appropriate proprioceptive training to the foot and ankle should be implemented to properly re-educate the normal bio-mechanical function and response time. Cuboid syndrome can be a very painful and frustrating injury, but fortunately it is a condition that responds well to conservative treatment (chiropractic, soft tissue manipulation, and rehabilitation).