KS105–Leg Flexion and Extension Trainer—Bilateral Hydraulic Knee Rehabilitation

The AE-KS105 Leg Flexion and Extension Trainer is a clinical-grade bilateral knee flexion and extension rehabilitation machine. The device strengthens the muscle chain of the active and antagonistic muscles. On the premise of ensuring the safety of patients, carry out efficient training.

The KS105 trains the quadriceps femoris — comprising rectus femoris, vastus medialis, vastus lateralis, and vastus intermedius (knee extension — the straightening phase) — and the hamstrings and gastrocnemius (knee flexion — the bending phase) through bidirectional hydraulic resistance. The training effect covers: quadriceps femoris, semitendinosus, semimembranosus, biceps femoris, sartorius, gracilis, internal gastrocnemius, and external gastrocnemius. It can improve low back pain, back pain, runner's knee and other symptoms.

Key Features —

Two-Way Hydraulic Resistance — Low Inertia from Lowest Limit The two-way hydraulic resistance can start from the lowest limit set, with small inertia, so as to avoid damage to patients during use. 

For knee rehabilitation specifically, the low-inertia, lowest-limit hydraulic resistance is not simply a convenience — it is a clinical safety prerequisite. The populations most commonly treated on the KS105 include:

1. Post-TKA patients (days–weeks post-surgery): Any inertial force spike at exercise initiation could cause pain, protective muscle guarding, or compromise the surgical repair. The hydraulic resistance's smooth-start mechanism enables exercise to begin at truly minimal loading.
2. Post-ACL reconstruction patients: Quadriceps loading must be carefully graded in the early rehabilitation phase to avoid graft stress. The lowest-limit hydraulic resistance enables the precise, minimal initial loading that early-phase ACL rehabilitation demands.
3. Elderly patients with significant quadriceps atrophy: The ability to begin at near-zero resistance allows patients who cannot generate meaningful voluntary knee extension force to begin therapeutic loading immediately.

The two-way resistance — providing hydraulic loading in both the extension (quadriceps concentric) and flexion (hamstrings concentric) directions — means every repetition delivers bilateral, balanced training stimulus to both muscle groups without requiring separate exercises.

• Bilateral Simultaneous Knee Training The KS105 trains both the left and right knee simultaneously in a coordinated bilateral movement pattern. This bilateral design:
• Maximises session efficiency — both legs trained together in the same time a single-leg machine would treat one

1. Supports symmetrical strength development — critical for the bilateral quadriceps symmetry needed for normal gait
2. Provides bilateral cortical motor engagement — particularly valuable for stroke patients where bilateral simultaneous lower limb movement activates bilateral cortical circuits
3. Enables direct side-to-side comparison of relative force — identifying asymmetries for targeted rehabilitation focus

• Ergonomic Knee Joint Contact Design Special design is adopted for the stressed parts of joints, which conforms to the principle of human morphology. The KS105's shin pad contact point, seat position, and pivot axis are designed to align the resistance vector with the natural biomechanical axis of tibiofemoral knee extension — minimising shear stress at the tibiofemoral and patellofemoral joint surfaces during exercise. This alignment is critical for: 

1. Post-TKA patients: Correct force vectors preserve implant stability and minimise wear
2. Patellofemoral pain patients: Correct knee alignment minimises lateral patellar tracking stress during knee extension
3. Post-fracture patients: Force vectors within safe anatomical planes protect healing bone and soft tissue