Knee Pain When Climbing Stairs — Patellofemoral Syndrome and Chondromalacia: Causes and Home Care

According to data from the American Orthopaedic Society for Sports Medicine (AOSSM), patellofemoral pain syndrome accounts for approximately 25% of outpatient knee pain visits, with a particularly high prevalence among urban residents and middle-aged adults who frequently use stairs. The primary reason knee pain occurs on stairs is that the knee joint is subjected to pressure 3 to 7 times greater than during level walking — applied in a very short period. This article provides a systematic overview of the anatomical causes of knee pain when climbing stairs, practical everyday management strategies, and how near-infrared LED care can serve as a supportive home routine.

During level walking, the ground reaction force on the knee joint is roughly 1 to 1.5 times body weight. When climbing stairs, however, the pressure concentrated on the cartilage surface between the patella (kneecap) and femur rises to 3 to 4 times body weight going up and 4 to 7 times body weight going down. This repeated high-pressure load in a short time promotes inflammation in the soft tissues around the knee and stimulates pain receptors.

In particular, the patella glides up and down along the femoral trochlear groove as the quadriceps contract during stair movements. Even a slight deviation from this path causes a sharp increase in cartilage friction. A 'grating' sensation in the knee or a 'pressing pain deep in the front of the knee' are the hallmark symptoms.

Patellofemoral Pain Syndrome (PFPS) is functional pain that arises when excessive, repetitive pressure is applied to the cartilage surface between the patella and femur. Pain can occur even without obvious structural damage, and tends to worsen when rising after prolonged sitting or during squatting movements.

Chondromalacia Patellae is a structural change in which the cartilage on the back of the kneecap gradually softens and its surface becomes roughened. Early symptoms are similar to PFPS, but MRI or arthroscopy can distinguish the degree of cartilage damage (Outerbridge Classification Grade I–IV). Both conditions are major causes of knee pain when climbing stairs, and at an early stage, symptoms can be meaningfully improved through appropriate exercise, posture correction, and home care.

Many people report that 'going down the stairs hurts far more.' The key to this phenomenon lies in eccentric contraction. When climbing stairs, the quadriceps shorten as they contract — this is concentric contraction. When descending, however, the muscles must simultaneously contract and lengthen. This eccentric contraction places greater tension on the muscle-tendon complex and creates conditions in which the patella struggles to maintain alignment over the femur.

Additionally, going downstairs tends to require a deeper knee flexion angle to control gravitational acceleration, which narrows the patellofemoral contact area and increases pressure per unit area. This is the biomechanical reason why 'going down hurts more than going up.'

The table below summarizes the patellofemoral joint pressure generated during everyday activities, expressed as multiples of body weight. Understanding these figures helps you decide which movements to avoid and at what range to begin rehabilitative exercise.

During painful periods, minimizing stair use and taking elevators or escalators helps protect cartilage. When beginning rehabilitation exercises, it is recommended to start squats within 60° of knee flexion.

Three key risk factors worsen knee pain when climbing stairs.

1. Excess body weight — Every 1 kg of additional body weight adds approximately 4 to 7 kg of extra knee pressure during stair activities. Research shows that PFPS prevalence increases significantly at a BMI of 25 or above. Clinical data also indicate that even a 5% reduction in body weight can improve knee pain scores by an average of 18%.

2. Weakness of the quadriceps and gluteal muscles — Weak muscles around the knee reduce the ability to keep the patella on its correct path. In particular, weakness of the vastus medialis oblique (VMO) and gluteus medius causes lateral patellar deviation, intensifying pain.

3. Knee misalignment — Valgus collapse (knees caving inward), overpronation (excessive inward foot rotation), and femoral internal rotation due to hip weakness all interact. These alignment problems can often be identified in a mirror and it is important to work with a therapist or physician to develop a correction strategy tailored to the underlying cause.

Using the correct technique on stairs can reduce knee load by 20 to 30%. Try applying the following principles in your daily life.

Going up — Place your whole foot on the step and keep your knee tracking over your second toe. Consciously engage your glutes and think of pushing up through your hip rather than your knee. Lightly gripping the handrail helps distribute knee load.

Going down — Lead with your heel and slowly transfer weight without letting your knee push too far forward. When pain is severe, stepping down sideways (crab-step) one step at a time is also effective. Rushing down stairs multiplies impact forces by three times or more, so always control your speed.

Footwear — Shoes with adequate cushioning or arch-support insoles help absorb impact. High-heeled shoes distort knee flexion angles on stairs and can worsen pain.

Below are strengthening exercises that can be started safely even when knee pain is present. Perform only within a range where pain stays at 0–3 out of 10, and stop immediately if pain increases.

Phase 1: Acute / Pain Relief Stage (Weeks 1–2)

• Quad Sets — Sit with legs extended and a rolled towel under the knee. Tighten the quadriceps and hold for 5 seconds, 10 reps × 3 sets. Activates the VMO without knee flexion.
• Straight Leg Raise (SLR) — Lying down, lift one leg to 45°, hold 5 seconds, then lower slowly. 10 reps × 3 sets.
• Clamshell — Lying on your side with knees bent 45°, open and close the top knee only. Strengthens the gluteus medius. 15 reps × 3 sets.

Phase 2: Sub-Acute / Functional Strengthening Stage (Weeks 3–6)

• Mini Squat (0–45°) — Back against a wall, distribute weight evenly across both feet and slowly lower then rise. 12 reps × 3 sets.
• Hip Bridge — Lying on your back, lift the pelvis to simultaneously strengthen the glutes and hamstrings. 15 reps × 3 sets.
• Side Step (resistance band) — Band around ankles, walk sideways. Strengthens the gluteus medius and external rotators. 15 steps each direction × 3 sets.

Phase 3: Return-to-Function Stage (6 Weeks Onward)

• Lunge (narrow stance) — Start with a short stride to keep the front knee from going past the toes. 10 reps × 3 sets.
• Step-Up — Step onto a low box (10–15 cm) and lower slowly. Perform the eccentric descent phase especially slowly. 10 reps × 3 sets.

Near-infrared (NIR) LED care uses the principle of photobiomodulation (PBM) to support blood flow, relaxation, and anti-inflammatory responses at the cellular level. The 850 nm wavelength can penetrate up to approximately 5 cm beneath the skin, reaching the muscles and soft tissues surrounding the knee joint.

In particular, applying NIR LED care after stair use or exercise when warmth and stiffness linger around the knee, in the morning when the knee feels stiff, or as a warm-up before activity can support a consistent everyday care routine. The recommended usage is 10 to 15 minutes per session, focused on the area around the patella and the front of the thigh, 4 to 5 times per week.

Near-infrared LED care does not replace medical treatment. Diagnosing and treating the cause of pain must always be left to a qualified healthcare professional. Individual results may vary.

If any of the following symptoms appear, do not rely solely on self-care — consult an orthopedic surgeon or sports medicine specialist.

• Swelling — Noticeable swelling of the knee or a sensation of fluid accumulation
• Locking — The knee suddenly locks at a certain angle and cannot be straightened (possible meniscus damage)
• Persistent severe pain — Pain of 5 out of 10 or more at rest, or pain that wakes you at night
• Sudden giving way — The knee suddenly buckles while descending stairs
• Post-traumatic pain — Pain that began after a fall, collision, or other external force
• No improvement after 3 weeks — No relief despite consistent self-care and exercise

The content of this article is intended for general health information purposes only and does not replace medical diagnosis or prescription. Appropriate management varies by individual condition; professional consultation is strongly recommended.