A grappler clamps both hands around a prone opponent's foot and twists it inward, capturing the moment of control and rotation in a foot lock
Photo: Tabercil · Wikimedia Commons · CC BY-SA 3.0

Foot Twisted to the Edge, Pain Arriving a Beat Late?
BJJ Toe Hold Rotational Lever Mechanics, IBJJF Belt Rules and Ankle-Saving Escapes

You are in 50/50 trading foot attacks when your opponent suddenly grabs your foot, one hand over the instep and one cupping the heel, and rotates the foot down and inward. There is none of the slow, dull crush you feel when a straight ankle lock bottoms out on your instep, just an odd "stuck" sensation on the outside of the ankle and around the heel, and by the time you register that something is wrong and try to pull the leg out, the foot has already been rotated past its limit. The toe hold is a rotational leg lock: you grab the foot, lock a figure-four grip, and rotate the foot toward plantarflexion plus inversion, twisting the talocrural joint (the ankle proper) and the subtalar joint at the same time and loading exactly the same lateral ligaments that get injured in an ordinary rolled-ankle sprain. Its most dangerous feature is not how sharply it hurts but that the pain often arrives a beat late, and by the time you feel something sharp the ligaments have usually already been stretched too far. This article draws on PubMed literature to break down the rotational lever mechanics of the toe hold, the loading pattern on the ATFL and CFL, why IBJJF restricts it to brown and black belts, the injury bill it runs up at the ankle, and an 8-week ankle-protection and escape program.

1. What the Toe Hold Is: A Rotational Lock That Turns the Foot Down and In

At its core, the toe hold uses rotation to force the foot into a combined position of excessive plantarflexion plus inversion, meaning the toes are driven downward while the sole turns toward the midline. One hand grips the instep near the metatarsal heads, the other reaches around under the sole to cup the heel, and the two hands lock into a figure-four on the outside of the shin. The instep hand then rotates down and inward, turning the whole foot into a lever that pivots around the heel. The quickest way to understand it is as "an ankle lock that works by rotation rather than pure compression": unlike a straight ankle lock, which bottoms out by pressing the instep in a straight line, the toe hold works by rotating the foot and winding up multiple joint surfaces of the ankle and foot.

Its entries almost all come from leg entanglements and foot-to-foot exchanges: the classic ones are 50/50, the saddle (411 / inside sankaku) and the various ashi garami positions, where you have already trapped one of the opponent's legs and simply reach up to wherever the foot happens to be; it also appears the instant an opponent extends the foot to defend a straight ankle lock and effectively hands you the sole. Because it twists a weight-bearing joint with short ligaments and works on a short lever arm, the "you are being stretched" warning it feeds back to the person being locked is much weaker than you would expect, which is exactly why so many people call it sneaky.

The word "rotation" is the key to understanding the risk. Ligaments around a weight-bearing joint are built to resist everyday pulling and twisting, but when the foot is used as a lever and rotated quickly past its limit, the load concentrates on a few short, strong lateral ligaments whose proprioceptive receptors are relatively sparse. By the time the pain signal arrives clearly, the structure is often already overloaded. Understanding how that rotational lever works is both the key to finishing the submission cleanly and the basis for judging when tapping is non-negotiable.

The Three Control Requirements of a Toe Hold

A locked figure-four (the frame): both hands lock into a figure-four on the outside of the opponent's shin, framing the foot securely. This is the structure through which force is applied; if the frame loosens and the foot can rotate back, the whole submission leaks power.
Heel as the axis, foot as the lever arm: the hand cupping the heel fixes it as an axis of rotation while the instep hand rotates the foot down and inward, so the foot sweeps an arc around the heel. That is what creates plantarflexion plus inversion.
Trapping the opponent's leg with your legs (no free leg): use both legs to wrap the opponent's thigh and knee so he cannot roll with your rotation and dump the tension, and so the torque stays locked at the ankle instead of spilling into the knee.

When all three hold at once, a small wrist rotation is enough to take the opponent to the limit of the outer ankle within a very short range of motion. Without your legs pinning his, he simply rolls with the rotation and sheds the force; without a tight figure-four, the foot rotates back. These are the two most common reasons beginners fail to finish a toe hold.

2. Rotational Lever Mechanics of the Foot: Two Joints Twisted at Once

To understand the destructive potential of the toe hold, start with what it actually twists. Unlike a straight ankle lock, which forces plantarflexion in a single direction, the toe hold acts simultaneously on the talocrural joint (the ankle proper, governing dorsiflexion and plantarflexion) and the subtalar joint (between the talus and calcaneus, governing inversion and eversion of the foot). When the foot is rotated downward and inward, both joints are pushed into the corners of their range at once, while the midfoot joints and plantar fascia also go taut. With nowhere to disperse, the force concentrates on the handful of ligaments on the lateral side of the ankle.

The structures taking that torque are precisely the ligaments injured in a rolled ankle: the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL). Multiple technical and rehabilitation analyses agree that the plantarflexion plus inversion the toe hold drives the foot into is exactly the position in which the ATFL and CFL are at maximum tension, so the injury pattern it produces overlaps heavily with a lateral ankle sprain. The only difference is that the toe hold uses a lever to push the foot past that angle quickly and deliberately. Think of the foot as a lever arm with the heel as the fulcrum and you will see how a small wrist rotation is amplified into considerable torque at the end of the lever.

The toe hold also carries one frequently overlooked but critical risk: when the opponent's leg is trapped and the foot is rotated outward, the tibia is dragged into external rotation and the torque can travel up the shin and "spill over" into the lateral side of the knee, loading the lateral collateral ligament (LCL) and surrounding structures. That is why, when applying a toe hold, you must clamp the opponent's thigh and knee with both legs to keep the torque locked at the ankle. Once the moment escapes and starts twisting the knee, the injury mechanism upgrades from a relatively local ankle sprain to a high-cost compound load involving knee rotation. The essence of finishing a toe hold is the same as with any leg lock: tight frame, stable axis, slow rotation. You take out the slack first, then rotate a small angle, rather than cranking with brute force.

3. IBJJF Belt-Level Rules: Why It Waits Until Brown and Black

Precisely because the toe hold works by rotation and twists short ligaments with sparse feedback, IBJJF places it later in the belt progression than the straight ankle lock. Under IBJJF gi rules (compiled from the IBJJF rule book and several published rule summaries): white belts may not use any leg lock; adult blue and purple belts are limited to the straight ankle lock only; and the toe hold, like the kneebar and the calf slicer, becomes legal only at adult brown and black belt.

Belt (adult, gi) Straight Ankle Lock Toe Hold Kneebar Heel Hook
White Not allowed Not allowed Not allowed Not allowed
Blue / Purple Allowed Not allowed Not allowed Not allowed
Brown / Black Allowed Allowed Allowed Not allowed (gi)

A finer point is the restriction on the direction of force: under IBJJF gi rules, brown and black belts applying a toe hold may not apply outward pressure to the foot and may only rotate inward, because outward rotation channels the torque in a more dangerous direction. In no-gi, IBJJF opened the heel hook and reaping to brown and black belts from 2021, and the same round of liberalisation also allows brown and black belts to apply outward pressure with the toe hold in no-gi. The simple version: gi is stricter and inward rotation only; no-gi is looser for brown and black belts and permits outward rotation as well. At blue and purple belt and below, the toe hold is illegal in both gi and no-gi.

This progression is not bureaucratic box-ticking; it reflects the reality that rotational leg locks require more mature control and a better shared understanding of tapping before they are safe. The straight ankle lock is pure compression with clear feedback, so it starts at blue belt. The toe hold rotates, gives delayed feedback and can drag the knee in, so it is prudently held back to brown and black. ADCC and submission-only rulesets are more permissive with leg locks, but the safety logic that lower belts get fewer options and rotational leg locks open last is consistent.

One more red line applies at every belt: knee reaping is prohibited outright. Reaping occurs when you fix the opponent's hip and ankle simultaneously while twisting the outside of his knee toward the midline. If you fail to clamp the opponent's leg while applying a toe hold and let the torque spill into the knee, you are not only disqualified, the injury mechanism also shifts from a relatively simple ankle sprain to a far more dangerous compound knee-rotation load. Keeping the torque strictly at the ankle, with the leg and knee held on their own line and not dragged into your rotation, is the baseline for both legality and safety.

4. The Attack Tree: The Toe Hold as the Rotational Branch of the Leg-Entanglement Web

The value of the toe hold lies in how it chains with the straight ankle lock and the rest of the leg-entanglement game. The underlying logic is simple: once you control one of the opponent's legs with an entanglement, you force a choice. If he extends and rotates the foot to defend the straight ankle lock, he hands you the sole and you switch to the toe hold; if he pulls the foot back to defend the toe hold, he opens the position for you to upgrade control or attack another leg lock. Here are the four most common entries and chains.

ENTRY 1
Toe hold off the 50/50 foot-lock exchange

From the symmetric 50/50 entanglement, both players can attack the other's foot. When the opponent is busy defending your straight ankle lock and gives up the sole, grab the foot, lock the figure-four and rotate inward to finish. Most common in the closing minutes of a foot-attack battle.

ENTRY 2
Upgrading from saddle / ashi garami

From the saddle (inside sankaku) or a single-leg entanglement with one of the opponent's legs firmly controlled, the foot sits right by your hands, so you lock the toe hold frame and rotate. The tighter the entanglement and the more his leg is pinned, the higher the finishing rate.

ENTRY 3
Straight ankle lock defended, switch to the toe hold

When you attack the straight ankle lock and the opponent dorsiflexes hard to slide the heel out of your forearm, his sole rotates into an angle that is easier for you to grab. Follow his defence, grab the instep, lock the figure-four and switch from compression to rotation. His defence opens a second finish.

ENTRY 4
Toe hold ↔ kneebar exchange (brown/black)

When the opponent straightens the leg and resists the rotation, brown and black belts can move the fulcrum up to the back of the knee for a kneebar, or cut back to the straight ankle lock. Foot and knee attacks answer each other, and it is the control chain rather than any single move that does the work.

Train these entries as one connected web and the toe hold stops being a gambling move and becomes the rotational branch of a stable leg-entanglement system. The practical mindset is this: once you have the foot, do not rush to crank. First close three gaps: a tight figure-four, a fixed heel axis, and both of your legs clamping the opponent's leg. Only then decide whether to rotate slowly for the finish or to follow his defence into another leg lock or sweep. Whether a leg lock finishes usually comes down to whether the control is at 80 percent or 100 percent rather than how hard you rotate, and that is especially true for a rotational submission like the toe hold, because cranking hard without full control is the fastest way to throw the torque into the opponent's knee or wrench your own lower back.

5. The Ankle Injury Bill: The Toe Hold Is the Leading Submission Cause

The toe hold directly rotates the ankle and several joints of the foot, so the injury risk sits mainly with the person being submitted. Placed back into the overall picture of lower-limb injury in BJJ, the data is clear enough that anyone who trains leg locks should remember it, and it explains why ankle injuries from submissions are not rare, with the toe hold as the main character.

The lower limb is the most commonly injured region in BJJ, and most ligamentous ankle injuries happen during submissions, with the toe hold ranking first. The large survey by Hinz et al. (2021, Orthop J Sports Med, n=1,140, across 62 countries) reported that over a three-year period, 784 of 1,140 practitioners were injured at least once, for 1,052 injuries in total; the lower limb accounted for 45.7% of all injuries, with the knee at 27.1% the single most affected joint, while 77.6% of injuries occurred during sparring and about 29.7% were caused by submissions. More directly relevant here: the study recorded 46 ligamentous ankle injuries (in 45 athletes), of which 60.9% occurred during submissions, with the most common causes in order being the toe hold (14 athletes), the straight ankle lock (8) and the heel hook (6). In other words, in this large sample the toe hold was the single technique responsible for the most ligamentous ankle injuries, ahead of both the straight ankle lock and the heel hook, which fits perfectly with its rotational, delayed-feedback mechanics.

Competition settings and "toughing it out" are what amplify the risk. Scoggin et al. (2014), analysing BJJ competition injuries, documented ATFL sprains of the ankle under footlocks and listed excessive joint loading among the common competition injury mechanisms, while the literature consistently finds that most BJJ injuries occur in sparring. The toe hold scenario, in which the person being locked resists because the pain arrives late while the attacker keeps adding rotation, is exactly the situation in which things go wrong in sparring and competition. It is worth stressing that when the toe hold only involves the lateral ankle ligaments, its overall destructiveness is usually less than a heel hook rotating the knee (which frequently causes high-cost ACL and meniscus damage), and that is also why the gi rules forbid outward pressure. But "safer than the heel hook" is emphatically not "safe to resist", given that it produced the highest count of ankle sprains in Hinz's data.

Key Data: BJJ Ankle Injuries and Toe Hold Mechanics (PubMed Literature)

・Hinz (2021, n=1,140): lower limb 45.7% of injuries, knee 27.1%; 77.6% of injuries occurred in sparring, 29.7% were caused by submissions; of 46 ligamentous ankle injuries, 60.9% occurred during submissions, with the toe hold leading at 14 athletes, the straight ankle lock at 8 and the heel hook at 6.
・Scoggin (2014): ATFL ankle sprains from footlocks documented in competition, with excessive joint loading as a common mechanism, and most injuries occurring in sparring.
・The toe hold drives the foot into plantarflexion plus inversion, twisting the talocrural and subtalar joints together and concentrating load on the ATFL and CFL, the same ligaments injured in a lateral ankle sprain.
・Those lateral ligaments have relatively sparse proprioceptors, so the pain often arrives a beat late and the structure is usually already overloaded by the time it becomes severe.

What this means for the toe hold: the person being locked should tap the moment the outside of the ankle feels wound up, stuck or simply wrong, not wait for sharp pain or hold out hoping the foot slips free; the attacker should rotate slowly, give the partner time to react, keep the torque locked at the ankle by clamping the leg, never twist the knee, and never apply outward pressure in gi competition.

6. Three Layers of Escape: Solve It Before You Are Cranked

Escaping a toe hold is easier and safer the earlier you do it. Once the figure-four is locked, the heel is fixed as an axis and the rotation begins, tapping is all you have left. The defence below is split into three layers, ordered from "not yet entangled" to "about to be cranked", and the core logic is to get the foot out of the plantarflexion-plus-inversion injury position as early as possible, or to destroy the axis of rotation.

LAYER 1 · POSITION
Do not hand over your foot; be careful entering 50/50

Most toe holds begin with the opponent controlling one of your feet. Not casually feeding your foot into his hips from open guard, clearing your leg out of the entanglement immediately after passing to side control, and not lingering in 50/50 or the saddle are the cheapest prevention available. No foot, no raw material for the toe hold.

LAYER 2 · ANTI-ROTATION
Fight with the foot, push your toes toward him

The moment you feel the figure-four coming, actively drive the foot into dorsiflexion plus eversion against the plantarflexion and inversion he wants, and push your toes hard toward him ("booting" the foot) so he cannot close the frame. If you occupy the rotational angle first, the torque never builds, and this is the key line of defence for buying time.

LAYER 3 · EXIT
Roll with the rotation, spin the heel off the axis and pull out

Once you are caught, roll in the same direction as his rotation and use your whole body to spin the heel off the axis, then follow through and come on top. You must rotate with your entire body to absorb the slack rather than yanking the foot out with leg strength alone, because yanking simply feeds the ligaments into the torque.

LAST LINE · TAP EARLY
Rotated to the end and unable to turn out: tap

When the figure-four is locked, your anti-rotation has failed, the foot is past its inversion limit and the whole leg cannot move, the only correct option is to tap immediately. Toe hold pain lags, so do not use severe pain as your signal; the lateral ligaments are already loaded before the pain peaks. Tapping is judgement, not weakness.

Stage Your situation Priority response Mechanical reason
He has just controlled your foot Foot hugged, you can still move Clear the leg, exit the entanglement, turn toward him No raw material, so the toe hold cannot be built
He is closing the figure-four Frame nearly set, foot still mobile Dorsiflex plus evert the foot, push the toes at him Occupying the opposite angle first keeps the frame from closing
He starts rotating the foot inward Caught, but your whole body can still roll Roll the same direction, spin the heel off the axis Use the body to absorb slack, come on top, break the axis of rotation
Frame locked, past the inversion limit Anti-rotation failed, whole leg immobile Tap immediately The ATFL and CFL take the torque before the pain peaks (delayed feedback)

The practical principle: the cost of escape rises exponentially with each stage. Layer one takes almost no effort, layer three is a race of speed and timing, and at the last line only tapping remains. Drilling the "clear the leg, fight with the foot, roll with the rotation" reflex is far more useful than learning ten advanced escapes. Because the toe hold's feedback lags, you especially need to set your trigger early at "it feels stuck, something is off, deal with it now" rather than waiting for the unmistakable bottoming-out sensation you get from a straight ankle lock, given that it produced the most ankle sprains in the literature precisely by letting people ride past the moment they should have tapped.

Red flags that require an immediate tap or stop: ① As the person being locked, the moment the outside of your ankle feels wound tight, the heel feels "stuck" and the foot will no longer rotate back, do not wait for sharp pain or plan to hold out until it slips: tap now (toe hold pain lags, and the ATFL and CFL take the torque before the pain peaks); ② anyone with a history of rolled ankles, lax lateral ligaments or ankle instability should tap even earlier than average; ③ as the attacker, rotate slowly, clamp the opponent's leg so the torque stays at the ankle, never let the moment spill into knee rotation (reaping), and never apply outward pressure to the foot in gi competition; fast, forceful cranking and knee twisting are the biggest single cause of lower-limb injuries in the gym and a direct rule violation; ④ if after the submission the ankle cannot bear weight, the lateral ligament area is swollen and tender, or the joint feels persistently unstable or repeatedly rolls (suspected ATFL/CFL tear), get it assessed medically. In one sentence: toe hold pain lies to you, so tapping when it feels stuck, rotating slowly and never twisting the knee are how everyone gets to keep training.

7. Training Prescription: An 8-Week Program for Peroneals, Ankle Stability and Anti-Rotation

Training the toe hold safely and finishing it cleanly runs along two lines: as the person being locked, you need peroneal (evertor) strength to protect the lateral ankle under rotational and inversion loads, plus sharper ankle proprioception to resist the rotation a step earlier; as the attacker, you need stable core and hips so your control is complete rather than reliant on brute rotation, which also protects your own lower back from being wrenched by the twist. The four-phase protocol below follows sports-science principles.

PHASE 1 · PERONEALS AND EVERSION
Lateral ankle strength (3× per week)

Banded eversion 3×15, banded four-way ankle resistance (inversion/eversion plus dorsiflexion/plantarflexion) for 3 rounds, calf raises 3×12. The peroneus longus and brevis are the active resistors of inversion and the protectors of the ATFL and CFL, mapping directly onto the toe hold's inversion risk.

PHASE 2 · PROPRIOCEPTION AND ANTI-ROTATION
Ankle stability and reactions (3× per week)

Single-leg balance with eyes closed 3×30 s, single-leg squats on a balance pad 3×8, single-leg stability against random partner perturbations 3×30 s. Faster ankle proprioception compensates for the toe hold's delayed pain and lets you resist reflexively the moment it feels stuck.

PHASE 3 · HIPS AND ANTI-ROTATION CORE
Control and back protection (3× per week)

Glute bridges / hip thrusts 3×12, Pallof press 3×10 per side, dead bugs 3×10 per side, side planks 3×30 s. A stable core is what lets the attacker rotate the foot precisely rather than forcefully, and anti-rotation core work also protects your own back from being wrenched during a rotational finish.

PHASE 4 · TECHNICAL INTEGRATION
Slow-rotation and three-layer escape drills (2× per week)

With a partner at half resistance, drill "control the foot → lock the figure-four → rotate slowly until he taps" ten times each, keeping his leg clamped and the torque at the ankle with no knee twist; on the escape side, repeat the three-layer reflex of "clear the leg → fight with the foot → roll with the rotation" and build in the early decision to tap when it feels stuck.

Focusing training on peroneal eversion, ankle proprioception and an anti-rotation core has clear literature logic behind it: since Hinz (2021) shows that ligamentous ankle injuries mostly occur during submissions and that the toe hold leads with 14 cases, and since what the toe hold injures is exactly the ATFL and CFL that resist inversion, the peroneals that buffer inversion load and the ankle proprioception that reacts before the delayed pain arrives are the most practical insurance for the person being locked. Meanwhile, an anti-rotation core and stable hips let the attacker complete the control without spilling torque into the knee (reaping) and protect his own lower back. The same literature notes that most injuries occur in sparring, so slow rotation and escapes for the toe hold must first be drilled into reflexes at low resistance before going to full-intensity rolls. Blue and purple belts and below should not be applying the toe hold under gi rules anyway, and should start from the clearing and anti-rotation escape side.

8. Wrap-Up and Decision Guidelines

Viewed through mechanics and the literature together, the toe hold is fundamentally a rotational leg lock that frames the foot with a figure-four, uses the heel as an axis to rotate the foot into plantarflexion plus inversion, and twists the talocrural and subtalar joints simultaneously. It attacks the same ATFL and CFL injured in a rolled ankle, and because those lateral ligaments give sparse feedback the pain arrives a beat late. That is exactly why IBJJF designates it brown and black belt only, with outward pressure banned in gi competition, and it matches the fact in Hinz's (2021) data that the toe hold is the single technique responsible for the most ligamentous ankle injuries (14 athletes). The most accurate way to understand it is as the rotational branch of the leg-entanglement web that requires more mature control before it is safe.

The most effective evidence-based strategy has three layers: first, complete the control before you talk about finishing, locking the figure-four, fixing the heel axis and clamping the opponent's leg with both of yours so 100 percent of the torque stays at the ankle and none of it twists the knee; second, drill the escapes into stage-appropriate reflexes, clearing the leg the instant the foot is controlled, dorsiflexing and everting to resist as the frame forms, and rolling with the rotation to come on top once it starts; third, centre your training on peroneal eversion, ankle proprioception and an anti-rotation core, so the person being locked protects the lateral ankle and the attacker protects his control and his back, which maps directly onto the injury scenarios and mechanisms described by Hinz (2021) and foot-and-ankle biomechanics.

And when you are the one being locked and feel the outside of the ankle wind up, the heel stick and the foot refuse to rotate back, tapping immediately is judgement, not weakness, especially since toe hold pain lies to you and riding past the "stuck" moment can buy you ligament rehab measured in weeks or months. The people who play a clean leg-lock game and still train healthily for decades are never the ones most willing to crank or most determined to hold out; they are the ones with the cleanest control, the strictest respect for the rules against twisting the knee, and the best instinct for protecting themselves the instant the ankle sticks.

Three Takeaways

1. The toe hold is a rotational lock that drives the foot into plantarflexion plus inversion: a figure-four frames the foot, the heel serves as the axis and both of your legs clamp his, twisting the ankle and subtalar joints together and injuring the same ATFL and CFL as a rolled ankle.

2. It waits until brown and black belt: legal from brown belt under IBJJF gi rules with outward pressure prohibited, with outward rotation allowed only in no-gi; illegal at purple belt and below, and knee reaping is a DQ at every level.

3. The pain lags, and earlier escapes cost less: switch through the three layers of "clear the leg → fight with the foot → roll with the rotation", and tap the moment the ankle sticks and will not turn rather than waiting for severe pain; the attacker must rotate slowly and never twist the knee.

References

1. Hinz M et al. (2021). Injury Patterns, Risk Factors, and Return to Sport in Brazilian Jiu Jitsu: A Cross-sectional Survey of 1140 Athletes. Orthop J Sports Med;9(12). PubMed 34988235 (60.9% of ligamentous ankle injuries occurred during submissions, with the toe hold leading at 14 athletes, the straight ankle lock 8 and the heel hook 6; lower limb 45.7%, knee 27.1%)
2. Scoggin JF et al. (2014). Assessment of Injuries During Brazilian Jiu-Jitsu Competition. Orthop J Sports Med. PubMed 26535299 (footlocks causing ATFL ankle sprains; excessive joint loading as a common competition injury mechanism)
3. Rotational foot mechanics of the toe hold: plantarflexion plus inversion of the foot, twisting the talocrural and subtalar joints together and loading the ATFL and CFL (the same ligaments as a lateral ankle sprain). Kinematics of the Toe Hold (Dr. Mike Piekarski, PT, DPT) / BJJ Rehab. mmaleech.com
4. Anatomy of the ankle (talocrural) and subtalar joints, the lateral collateral ligaments (ATFL and CFL), and inversion/eversion range of motion. TeachMeAnatomy / Physiopedia. teachmeanatomy.info
5. IBJJF leg-lock belt progression and force-direction rules (adult gi: toe hold and kneebar restricted to brown and black belt, with outward pressure banned in gi; outward pressure allowed for brown and black belts in no-gi from 2021; blue and purple belts limited to the straight ankle lock; heel hooks and knee reaping banned at all levels in gi). Evolve / FloGrappling / IBJJF Rule Book. evolve-mma.com