Foot Drop - Gait Cycle

Gait Cycle

Drop foot and foot drop are interchangeable terms that describe an abnormal neuromuscular disorder that affects the patient's ability to raise their foot at the ankle. Drop foot is further characterized by an inability to point the toes toward the body (dorsiflexion) or move the foot at the ankle inward or outward. Therefore, the normal gait cycle is affected by the drop foot syndrome.

The normal gait cycle is as follows:

• Swing phase (SW): The period of time when the foot is not in contact with the ground. In those cases where the foot never leaves the ground (foot drag), it can be defined as the phase when all portions of the foot are in forward motion.
• Initial contact (IC): The point in the gait cycle when the foot initially makes contact with the ground; this represents the beginning of the stance phase. It is suggested that heel strike not be a term used in clinical gait analysis as in many circumstances initial contact is not made with the heel. Suggestion: Should use foot strike.
• Terminal contact (TC): The point in the gait cycle when the foot leaves the ground: this represents the end of the stance phase or beginning of the swing phase. Also referred to as foot off. Toe-off should not be used in situations where the toe is not the last part of the foot to leave the ground.

The drop foot gait cycle requires more exaggerated phases.

• Drop foot SW: If the foot in motion happens to be the affected foot, there will be greater flexion at the knee to accommodate the inability to dorsiflex. This increase in knee extension will cause a stair climbing movement.
• Drop foot IC: Initial contact of the foot that is in motion will not have normal heel-toe foot strike. Instead the foot may either slap the ground or the entire foot may be planted on the ground all at once.
• Drop foot TC: Terminal contact that is observed in patients that have drop foot is quite different. Since patients tend to have weakness in the affected foot, they may not have the ability to support their body weight. Oftentimes, a walker or cane will be used to assist in this aspect.

Drop Foot is the inability to dorsiflex, evert, or invert the foot. So when looking at the Gait cycle, the part of the gait cycle that involves most dorsiflexion action would be Heel Contact of the foot at 10% of Gait Cycle, and the entire swing phase, or 60-100% of the Gait Cycle. This is also known as Gait Abnormalities.