Under the existing GPUK grounded-opponent definition, a fighter is grounded when any part of their body other than the soles of their feet touches the canvas. That includes a hand, knee, hip or torso. The referee applies this definition.
All submissions are permitted subject to the under-16 restriction below, except spinal locks, twisting ankle or leg locks, and leg reaping. The other listed fouls still apply, including the bans on neck cranks and small-joint manipulation. Foot locks and leg locks are not permitted in C class at any age. In A and B class, straight Achilles locks only are allowed for fighters aged 16 and over. Figure-four locks and finger locks are prohibited, as is reaping or twisting the knee or hip joint. Twisting ankle or leg locks and leg reaping are prohibited in every class. Spiking an opponent head- or neck-first into the canvas is prohibited in every class.
Foot locks and leg locks are not permitted in C class at any age. In A and B class, straight Achilles locks only are allowed for fighters aged 16 and over. Figure-four locks and finger locks are prohibited, as is reaping or twisting the knee or hip joint. No twisting ankle or leg locks: this includes figure-four ankle locks, heel hooks and toe holds. No leg reaping: this includes reaping that twists or torques the knee or hip joint. No spinal locks: this includes neck cranks and twisting the spine. A guillotine must remain a choke and must not become a neck crank.
Why these exclusions? The spinal-lock and neck-crank ban is intended to reduce the risk of neck and spinal injury. The twisting ankle-lock, twisting leg-lock and leg-reaping bans are intended to reduce the risk of injury to the ankles, knees and hips. Straight Achilles foot locks are permitted in A and B only; straight knee bars in A only. C class prohibits every foot lock, knee bar and other leg-lock submission at every age. Under-16s are C class only. The spiking ban is intended to reduce the risk of head and neck injury from being driven into the canvas. These restrictions do not remove all risk from MMA.
All submissions must be released immediately when an opponent taps or verbally submits, the referee stops the action, or the round ends. Read your class panel for ground-striking limits. Junior age-specific submission limits must be confirmed before the bout.