Knee and hamstring osteoarthritis: Why does the back of the thigh weaken? A new study explains the causes.

Knee osteoarthritis: More than just a joint problem

Knee osteoarthritis (gonarthrosis) is one of the most common causes of pain in this joint. Many patients report not only pain but also a feeling of instability. Recent research shows that this feeling of instability is often related to a loss of strength in the hamstrings, the muscles at the back of the thigh.

Current research: The hamstrings are more affected than previously thought.

 Although it has long been known that the quadriceps lose strength in knee osteoarthritis, a new study provides crucial information about the back muscles:

The hamstring muscles of patients with osteoarthritis show significantly reduced strength values.

The ability to remain stable in the face of increasing stress is particularly limited.

The most affected leg shows up to 40% less gripping strength than healthy control subjects.

This form of gripping force – the so-called adaptive force – is crucial for many everyday movements.

Why do hamstrings lose strength in osteoarthritis?

1. Pain inhibits muscle control

Pain signals from the joint can reduce muscle activity.

As a result, the leg reacts more slowly and with less stability.

2. Avoid movement and adopt a protective posture

Many people put less pressure on the sore knee.

This automatically leads to further muscle loss, often unnoticed.

3. Protective reflexes of the nervous system

The body tries to protect the joint by reducing the force with which the muscles contract.

However, this leads to greater instability.

Why are the hamstrings so important for knee stability?

The back of the thigh performs key functions:

• Stabilization of the knee joint

• Control when climbing stairs

• Safety while descending

• Anterior cruciate ligament protection

• Braking and interception movements

If the hamstrings weaken, the following things may occur:

• increased joint stress

• a feeling of trembling or insecurity in the knee

• faster fatigue

• increased risk of falls or injuries

What implications does this have for the treatment of knee osteoarthritis?

1. Training should not consist solely of strength exercises.

Of course, strength training is important, but the study shows that gripping and braking strength are crucial.

These skills are constantly needed in everyday life.

2. Neuromuscular training is essential.

This includes:

controlled deceleration of movements

Resistance exercises against increasing load

sensorimotor training

eccentric hamstring training

3. Individualized therapy for long-term stability

A patient-tailored training plan improves:

• joint function

• stability

• pain reduction

• Daily security

• Conclusion: Strong hamstrings protect the knee

The new findings demonstrate that knee osteoarthritis affects not only the joint itself, but also neuromuscular control. The hamstrings, in particular, lose significant support strength.

The good news: this function can be significantly improved with specific physiotherapy.

Strengthening the hamstrings and rebuilding neuromuscular stability can:

Reduce pain

• Improve mobility

• slow the progression of osteoarthritis

• Gain greater confidence in your daily life.

The key is not in training harder.

The key is knowing which muscles need stabilizing and what therapy is required.

Fountain:

https://www.researchgate.net/publication/377180681_Adaptive_Force_of_hamstring_muscles_is_reduced_in_patients_with_knee_osteoarthritis_compared_to_asymptomatic_controls