The best answer to the question "Any good exercise to gain strength for back knee grip?" is not a single exercise, it is a shift in how you understand the grip itself. The original article frames this as a casual Q&A, but the underlying issue is one that almost every athlete encounters when they move from static holds to dynamic sequences: the knee grip is not a clamp; it is a hinge that requires active, engaged hamstring and quadriceps control. Treating it as a passive hook is why so many dancers lose their hold during a climb or a spin.
This connects directly to the broader conversation about controlled strength progression. Our article Building Your Pole Muscle Up with Controlled Strength Progression makes the case that the most impressive pole transitions are built on deliberate, incremental loading rather than explosive effort. The same principle applies here. A strong behind-the-knee grip is not developed by hanging from the pole and hoping your tendons adapt. It is developed by isolating the posterior chain in off-pole exercises, glute bridges, single-leg Romanian deadlifts, and seated hamstring curls, so that when you bring that strength to the pole, your knee flexes with purpose rather than desperation.
We also see a parallel with the mechanics discussed in From Ground Mount to Invert: Refining Your Aerial Shoulder Press. That article emphasizes how a shoulder press fails when the athlete tries to muscle through with the upper body alone, neglecting the role of the core and the engaged shoulder blade. The knee grip fails for the same reason: athletes try to grip with the knee in isolation, forgetting that the grip is anchored by active hip flexion and a braced core. A back knee grip that slips during a Gemini or a Superman is rarely a knee problem. It is a hip stability problem.
Our take is that this article does the pole community a service by drawing attention to a specific, often-neglected strength zone, but it should go further. The athlete needs to know that the "back knee grip" is not a grip at all in the traditional sense, it is a dynamic lock that relies on the same principles as a deadlift or a leg curl. If you cannot perform a controlled single-leg bridge on the floor, you will not have the motor control to hold a knee grip under load while inverted.
The concrete takeaway is this: before you add more reps on the pole, spend four weeks strengthening your hamstring curl and your glute-hamstring connection off the pole. Test it by holding a simple knee hook on a static pole at hip height for thirty seconds with your arms off the pole. If you cannot do that without your foot drifting away from the pole, your grip is not ready for dynamic work. The article points in the right direction; the next step is to treat that strength like any other foundational skill, train it separately, test it specifically, and only then integrate it into your flow.
