Buttercup is a combat-and-core circuit that runs knee strikes as the constant thread through the set, with climbers, shoulder taps, plank rotations, and punches woven through to build the posterior chain, anterior core, and rotational power that martial arts conditioning depends on. Knee strikes appear five times across the set, each time flanking a different exercise, so the hip flexors are under near-continuous demand while the core and upper body work around them. Across 3, 5, or 7 sets with up to 2 minutes of rest, the cumulative volume builds striking endurance alongside genuine functional strength.

Knee strikes drive the hip flexor and the glute of the standing leg simultaneously - the hip flexor pulls the striking knee up while the supporting glute stabilizes the pelvis and prevents the hip from dropping. Done with proper form, they also require the core to brace against the rotation that asymmetrical leg drive creates, making them a full-body movement despite looking like a leg exercise. The climbers between the first two knee strike blocks shift the work to the floor, loading the anterior chain and hip flexors through a different range. Shoulder taps ask for anti-rotation stability with the entire bodyweight on the hands, a direct contrast to the striking that frames them. Plank rotations in the middle of the set demand the obliques and shoulder girdle work together to move the body through a full side-plank transition. Punches close the final blocks with horizontal striking power, rotating the core in the opposite plane to the knee strikes and completing the full rotational picture.

Drive the knee up rather than forward on knee strikes. The power comes from hip flexion, not a forward kick.

To make it easier: Slow the knee strikes to a controlled lift rather than a driven strike, and perform climbers as deliberate step-throughs rather than driven reps. Perform plank rotations with the bottom knee on the floor for support.

To make it harder: Add a rear-leg drive at the top of each knee strike - the standing leg rises onto the ball of the foot as the striking knee peaks - to increase balance and calf demand. Sprint the climbers for all 10 reps and perform plank rotations with a 2-count hold in the full side-plank position.