Knee pain

Knee pain: understanding beyond the joint 

Knee pain is one of the most common complaints among both active and sedentary individuals. It can occur when walking, climbing stairs, running, squatting, or even at rest. Although we often think only of wear and tear, menisci, or ligaments, the clinical reality is usually broader: the knee does not function in isolation, but rather as part of a complex biomechanical chain involving the foot, ankle, hip, pelvis, and nervous system. 

From a modern perspective, knee pain does not always depend solely on a damaged structure, but also on how muscular loads are distributed, how the body moves, and how the nervous system interprets tension, threat, or overuse.

Most common symptoms of knee pain 

Symptoms can vary depending on the origin of the problem, but common symptoms include: 

• Pain in the anterior, lateral, or posterior aspect of the knee 

• Discomfort when climbing or descending stairs 

• Pain when running, jumping, or squatting 

• A sensation of stiffness or locking 

• Instability or a feeling of "giving way" 

• Swelling or overload 

• Clicking or mechanical discomfort 

• Tension around the patella, upper, lower, or posterior aspect of the knee 

In many cases, pain can persist even when there is no severe visible lesion, highlighting the importance of assessing not only tissues, but also function and neuromuscular control. 

Why does knee pain occur? 

The knee acts as an intermediate joint that receives and transmits forces between the hip and the foot. When any of these areas do not function properly, the knee can compensate and become overloaded. 

Common factors include: 

• Deficits in hip or gluteal control 

• Gait or foot strike alterations 

• Athletic or repetitive overload 

• Mobility restrictions in the ankle or hip 

• Muscle weakness 

• Inadequate rehabilitation following an injury 

• Nervous system sensitization

Biomechanics matter: the knee rarely works alone 

One of the most common mistakes is to focus solely on the painful area without analyzing how the rest of the body moves. 

For example: 

• An unstable hip can increase tension on the knee

• A stiff ankle can alter load distribution during gait 

• An inefficient gluteus can alter patellofemoral alignment 

This means that knee pain is often the visible consequence of an inefficient movement strategy. 

A frequently forgotten muscle: the popliteus 

Within the clinical approach to the knee, there is a structure that often goes unnoticed: the popliteus muscle. Located at the back of the knee, this small but vital muscle plays key roles such as: 

• Unlocking the knee when initiating flexion from an extended position 

• Contributing to internal rotation of the tibia 

• Assisting in posterolateral stability 

• Participating in dynamic control during gait and changes of direction

Important clinical fact: 

When the popliteus is overloaded, tight, or dysfunctional, it can generate localized pain behind the knee, but it can also cause referred discomfort to the anterior or lateral area. 

This can cause some individuals to perceive pain "somewhere else," when in reality part of the problem may originate in the posterior region. 

Why does this happen? 

Due to its stabilizing function and its relationship with the rotational control of the knee, the popliteus can be affected by repetitive activities, poor running mechanics, downhill running, sudden changes of direction, or muscular compensations. 

When not assessed correctly, it can become a persistent source of pain or instability. 

Neuroscience of pain: when knee pain persists beyond the tissue 

In some patients, pain persists even after the initial injury has healed. This can be related to increased sensitivity of the nervous system, sustained protective patterns, or fear of movement. 

The brain can increase the perception of threat, making normal activities feel painful. 

That is why effective rehabilitation does not only treat tissues, but also addresses confidence, motor control, and progressive exposure to movement.

Comprehensive therapeutic approach 

From a perspective based on biomechanics and neuroscience, knee pain treatment may include: 

• Manual therapy 

• Myofascial release 

• Deep dry needling 

• EPTE (Percutaneous Electrolysis Therapy) 

• Neuromodulation  

• Specific work on the popliteus and posterior chain 

• Gluteal strengthening and hip control 

• Therapeutic exercise 

• Load management and functional recovery 

In summary 

Knee pain does not always start in the knee. Often, it is the result of how different structures in the body interact and how the nervous system responds to load, tension, or movement. 

And in that comprehensive assessment, lesser-known muscles like the popliteus can make a big difference. Because understanding the knee does not just mean looking at where it hurts... it means understanding everything that influences how it moves.