You walk forward with your arms pinned behind you -- as a gym exercise? I don't doubt that you do something in the gym and that you may call it a frog march, but the only use of the term I have encountered in almost 80 years on the planet is as described in that definition, which doesn't appear to match anything anyone would do for exercise. Never heard of "frog" squats. Local vernacular, perhaps?
Frog walking, a term apparently limited to gym culture, is a different thing from frog marching, frog-marching, and frogmarching [all transitive], which in the literal sense mean carrying someone face down by all four limbs, in a semi-literal sense mean forcing someone's arms behind them and using them to propel the person forward, and in a figurative sense mean forcing at person to go somewhere they don't want to go. It's often done for show in any of those senses. But frog walking is a gym exercise precisely because it's so demanding. Long-term it's damaging to knee joints, and because of the discomfort and clumsiness it's not something you'd employ for stealth. Walking stooped (bent over at the back) with somewhat bent knees is what you'd do to move expeditiously with some degree of stealth. Someone might go a few steps in a squat, but only to gain a better vantage point behind some kind of cover, not really to proceed from point A to point B. Doing so would make more than usual noise in gravel or other noisy material. It would be safer and faster simply to go on hands and knees. It sounds like trying to describe this exactly is only going to distract from the narrative.
