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Leg weakness is usually a symptom of an underlying condition rather than a medical condition itself. It refers to a feeling of loss of strength in the lower limbs, which may or may not be accompanied by pain.
Weakness in the legs is often a result of physiological or pathological disorders, but there are cases when the loss of strength is totally perceived or psychological in nature.
The weakness may be felt in one or both legs. Diminished strength in only one leg is called monoparesis, whereas weakness in both legs is called paraparesis.
Possible Causes of Weak Legs
Several pathological and physiological conditions can result in weak legs. In some cases, these conditions might need urgent attention. In others, they are benign and taken care of without any complication.
Depending on the onset of symptoms, the etiologies can be categorized into “sudden onset” and “insidious onset.”
1. Sudden onset
- Stroke: Stroke is a result of a sudden blockage of blood supply to the brain. Depending on the involved part of the brain (cerebral cortex, brain stem, etc.), varying weakness of the legs can result. (1)
- Guillain-Barre syndrome (GBS): GBS is a flaccid paralysis that begins as leg weakness, progressing upward into the upper body. The majority of patients have a history of gastrointestinal infection, especially one caused by Campylobacter jejuni. (2)
- Ion-related paralysis (hypokalemia): Ion-related paralysis, also known as periodic paralysis, is a transient weakness in the legs due to disorders in electrolyte levels. Hypokalemia is the most common cause. It can occur in patients with renal disease. (3)
2. Insidious onset
- Disc herniation: Disc herniation is a spinal pathology in which the intervertebral disc herniates, most commonly from the posterolateral side of the vertebral column. (4) In some cases, this does not cause any symptoms. However, in severe cases, it can irritate and impinge the nerves and cause pain in the area of innervation, including the legs.
- Spinal stenosis: Spinal stenosis is a spinal condition in which the spinal canal is narrowed, compressing the nerve roots and spinal cord. This results in the perception of weakness and pain in the legs. This pain is particularly induced by walking and is called neurogenic claudication. (5)
- Prolonged immobilization after surgery: Prolonged immobilization leads to less frequent firing of the muscles. Eventually, the leg muscles start to atrophy due to disuse.
- Sedentary lifestyle: Lack of daily physical activity results in frail limb muscles, presenting as weakness and lack of strength in the legs.
- Sciatica: Sciatica is a neuropathy that occurs when the nerve roots are impinged while exiting the foramen in the spinal column. It manifests as episodic shooting pain from the hips down the back of the entire leg. (6)
- Peripheral neuropathy due to chronic diseases: In this condition, sensory nerve involvement is the most common cause. It results in paresthesia, loss of proprioception, and perception of weakness in the legs. Chronic diseases include diabetes mellitus (DM) and peripheral arterial disease (PAD). (7)
- Smoking: Smoking is associated with the slow progression of arterial diseases, chiefly thromboangiitis obliterans, which can reduce blood supply to the distal limb, triggering leg pain and weakness. (8)
- Aging: Aging is associated with generalized weakness as the muscle mass progressively decreases with increasing age.
Note: Functional limb weakness should always be ruled out. In this case, the patient manifests similar symptoms but there is no underlying neurological disease and all diagnostic tests are normal.
Measures to Regain Strength in Your Legs
The first step is to undergo a robust evaluation to find the cause of the weakness or pain in the legs, and the treatment strategy is determined based on the etiology.
When there is no severe disease:
- Active lifestyle – If the leg weakness is due to a comparatively benign cause, such as immobilization or aging, strength exercise training under a controlled environment with the right technique and protocol offers the most advantages. Proportionate weight training and cardio are recommended rather than an emphasis on one.
- Identification of the psychiatric factors
- Regular clinical follow-up
When there is a severe disease:
- Immediate medical assessment, diagnosis, and management
- Determination of the disease prognosis
- Comprehensive rehabilitation: A close follow-up with comprehensive rehabilitative measures should be implemented to help the patient walk again, which can be a long process. Unfortunately, some patients fail to return to their previous level of strength.
Muscle firing is responsible for the initiation of movement of the human body. The strength for the movement is proportionate to muscle mass.
A diet comprising more animal and plant protein is good for muscle health. Lean meats, egg whites, chickpeas, beans (kidney, black, and white), skim milk, Greek yogurt, etc., are abundant sources of protein and can help in strengthening the muscles.
Is Leg Weakness Always Accompanied by Leg Pain?
Not really. The symptoms depend on the cause of the condition. For instance, leg weakness due to sciatica is always accompanied by pain, but the one due to prolonged immobilization is not associated with any pain.
Due to the associated subjectivity, the intensity of the symptoms is highly variable.
Do Pregnant Women Suffer From Weak Legs?
Yes, some women do experience weakness in their legs. It is often of slow onset, with a feeling of heaviness in the legs. (9)
The leg weakness is primarily due to the increasing acting weight on the lower limbs due to the progressive weight gain in pregnancy and hormonal changes (estrogen).
The majority of affected women are known to regain strength a few weeks after pregnancy. If they do not, then a detailed clinical assessment is recommended.
People usually experience temporary weakness in their legs after performing a physically strenuous activity. In such cases, lost muscle strength can be recovered after resting the legs for a while.
However, if the leg weakness continues for several days despite proper self-care, it can indicate a more serious underlying problem that usually warrants medical evaluation.
The doctor will conduct the necessary tests and analysis to diagnose the root cause of the weakness and suggest the appropriate treatment to rehabilitate the legs.