The calf muscles consist of several muscles. This group of muscles is referred to as the plantarflexors. They stabilise the foot and enable a safe stance and gait. A paralysis or weakness of this muscle group is often described by the term calf muscle weakness (paralysis of the plantar flexors, weakness of the plantar flexors). It causes a very insecure stance and visible deviations when walking, which is associated with an increased energy consumption. To treat a weakness in the calf muscles, the use of crutches or walkers is still commonly recommended and prescribed. In the following, you will learn which treatment options are more suitable for this purpose.
In addition to the isolated paralysis of the plantar flexors, other muscle groups may also be affected. We explain the effects of paralysis of the dorsiflexors and plantar flexors as well as in combination with paralysis of the knee extensors and hip extensors in the corresponding videos. Part of the videos are still in progress and will be published soon.
You will find Overview of all Types of Paralysis on the home page.
We recommend that you first familiarise yourself with our online tutorial General Physical Examinaton. This is crucial for choosing the right orthosis using our Orthosis Configurator and an ideal starting point for fully understanding the following video.
Patients with an isolated weakness of the plantar flexors should be fitted with an orthosis of the following category:
The NEURO SWING-CLASSIC system ankle joint equipped with a dynamic and adjustable dorsiflexion stop. The range of motion and the spring force can be adjusted in dorsiflexion by interchangeable precompressed spring units. An AFO with a NEURO SWING-CLASSIC system ankle joint activates the forefoot lever and restores the physiological knee joint angle. The spring unit in the NEURO SWING-CLASSIC system ankle joint is sufficient to counteract the body weight, providing a secure stance and gait and to lift the heel for an energy efficient gait.
Such an AFO enables safe stance without muscle fatigue. When walking, a wider range of motion of the ankle joint restores a physiological gait and can help maintain the strength of healthy muscles. It also prevents hyperextension of the knee.
A properly designed AFO can completely replace traditional walking aids, such as crutches and walkers. Depending on the muscle strength and whether other muscle groups are affected by paralysis, a different type of orthosis with other system joints may be appropriate.
The video above provides a clear overview of the problems that paralysis of the plantar flexors can cause, the advantages of a treatment with an orthosis and the most suitable treatment option.
It is divided into different topics. Below you will find an overview and brief description of the respective chapters.
1. Compensating for Weak Plantar Flexors When Standing
1.1 Secure Stance due to Healthy Plantar Flexors
When standing, the plantar flexors help to keep the body’s centre of gravity above the feet, enabling a stable stance.
1.2 Insecure Stance due to Weak Plantar Flexors
In case of complete paralysis of the plantar flexors, the forefoot lever is not activated. As a result, the body can only be held in an unstable and unphysiological position.
1.3 Secure Stance due to the Correct Ankle-Foot Orthosis (AFO)
In case of weak plantar flexors an orthosis should be custom-made and include the three functional elements described in this chapter.
1.4 Types of Dorsiflexion Stops
This chapter explains the differences between the different dorsal stops and which one is most effective for plantar flexor weakness.
1.5 Function of an AFO with a NEURO SWING-CLASSIC System Ankle Joint
When standing with an AFO with a system ankle joint, its dynamic dorsiflexion stop activates the natural forefoot lever and fully counteracts the ground reaction force. The resistance can be adjusted through interchangeable precompressed spring units in a way that allows standing in a stable balance without additional walking aids.
2. Compensating for Weak Plantar Flexors When Walking
2.1. Physiological Gait due to Healthy Plantar Flexors
When walking the heel starts lifting up in terminal stance as the fully functioning plantar flexors are sufficient to lift the body weight.
2.2. Pathological Gait due to Weak Plantar Flexors
When standing, weak plantar flexors cannot activate the forefoot lever and stabilise the knee joint. This causes a hyperextension of the knee.
2.3. Comparison of a Physiological Gait and a Pathological Gait due to Weak Plantar Flexors
In this chapter, the two gaits are compared.
2.4. Comparison of a Pathological Gait due to Weak Plantar Flexors and a Physiological Gait due to the Correct Orthosis (AFO)
This chapter describes why a weakness of the plantar flexors causes a pathological gait and how the right orthosis can restore a physiological gait through targeted support.
Weak plantar flexors cannot lift the body weight, which results in a visibly impaired gait with high energy consumption. In the stance phases, they cannot stabilise the ankle joint. A hyperextension of the knee occurs.
An AFO with a NEURO SWING-CLASSIC system ankle joint enables a secure gait, as the integrated spring unit is sufficient to lift the body weight.
3. Problems of Traditional Treatments that Do Not Reflect the Latest State of the Art
3.1. Inadequate Types of AFOs to Use in Case of Weak Plantar Flexors
With this wrongly prescribed type of AFO the body’s centre of gravity can only be held in an unstable and non-physiological position. In this chapter, you will learn which types of orthoses are unsuitable.
3.2 Problems of Conventional Aids (e.g. Crutches, Walkers)
Unfortunately, the use of conventional medical devices is still prescribed far too often, because their disadvantages and the advantages of a modern orthosis as an option of treatment are not yet sufficiently known.